version 3.6.2

* NEWS: Record release date.
tests: improve update-test
2026-08-10 03:05:14 +00:00 · 2020-05-17 08:30:46 +02:00 · 2020-05-17 08:28:12 +02:00 · 2020-05-17 08:28:12 +02:00 · 2020-05-17 08:28:12 +02:00 · 2020-05-15 07:18:15 +02:00
73 changed files with 2292 additions and 1092 deletions
@@ -1 +1 @@
-3.5.4
+3.6.1
@@ -46,7 +46,7 @@ jobs:
        - ./bootstrap
        - ./configure --enable-gcc-warnings || { cat config.log && false; }
        - make -j2
-        - make -j2 dist
+        - make -j2 dist-xz
        # Can help understanding why we get "dirty" tarballs.
        - git status
        - dist=$(echo bison*.xz)
@@ -69,53 +69,53 @@ jobs:

    # Start with three completely different environments, to get errors asap.

-    - name: "GCC 9 -O3"
+    - name: "GCC 10 -O3"
      stage: check
      os: linux
      dist: bionic
-      addons: &gcc9
+      addons: &gcc10
        apt:
          sources:
            # See https://github.com/travis-ci/apt-source-safelist/issues/410.
            - sourceline: 'ppa:ubuntu-toolchain-r/test'
-          packages: g++-9
+          packages: g++-10
      env:
-        - CC=gcc-9
-        - CXX=g++-9
+        - CC=gcc-10
+        - CXX=g++-10
        - CONFIGUREFLAGS='CPPFLAGS=-DNDEBUG CFLAGS=-O3 CXXFLAGS=-O3'

    # ASAN is time consuming, and we timeout the 50min granted by
    # Travis if we run all the tests in one go.  Run in two parts.
-    - name: "Clang 9 libc++ and ASAN part 1"
+    - name: "Clang 10 libc++ and ASAN part 1"
      stage: check
      os: linux
      dist: bionic
-      addons: &clang9
+      addons: &clang10
        apt:
          sources:
            # See https://github.com/travis-ci/apt-source-safelist/issues/410.
            - sourceline: 'ppa:ubuntu-toolchain-r/test'
-            - sourceline: 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-9 main'
+            - sourceline: 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-10 main'
              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
          packages:
-            - clang-9
-            - libc++-9-dev
-            - libc++abi-9-dev
+            - clang-10
+            - libc++-10-dev
+            - libc++abi-10-dev
      env:
        # Do not use ASAN with ubuntu's libc++: https://bugs.llvm.org/show_bug.cgi?id=17379
-        - CC='clang-9 -fsanitize=address'
-        - CXX='clang++-9 -fsanitize=address -stdlib=libc++'
+        - CC='clang-10 -fsanitize=address'
+        - CXX='clang++-10 -fsanitize=address -stdlib=libc++'
        - PART=1

-    - name: "Clang 9 libc++ and ASAN part 2"
+    - name: "Clang 10 libc++ and ASAN part 2"
      stage: check
      os: linux
      dist: bionic
-      addons: *clang9
+      addons: *clang10
      env:
        # Do not use ASAN with ubuntu's libc++: https://bugs.llvm.org/show_bug.cgi?id=17379
-        - CC='clang-9 -fsanitize=address'
-        - CXX='clang++-9 -fsanitize=address -stdlib=libc++'
+        - CC='clang-10 -fsanitize=address'
+        - CXX='clang++-10 -fsanitize=address -stdlib=libc++'
        - PART=2

    - name: "ICC"
@@ -135,46 +135,41 @@ jobs:
          packages:
          - intel-oneapi-icc

-    ## ------- ##
-    ## First.  ##
-    ## ------- ##
-
-    # Start with three completely different environments, to get
-    # errors asap.
-
-    - name: "ARM64: GCC 9 -O3 part 1"
+    - name: "ARM64: GCC 10 -O3 part 1"
      stage: check
      os: linux
      arch: arm64
      dist: bionic
-      addons: *gcc9
+      addons: *gcc10
      env:
-        - CC=gcc-9
-        - CXX=g++-9
+        - CC=gcc-10
+        - CXX=g++-10
        - CONFIGUREFLAGS='CPPFLAGS=-DNDEBUG CFLAGS=-O3 CXXFLAGS=-O3'
        - PART=1

+    # GCC10 on PPC seems to be buggy.
+    # E.g., https://travis-ci.org/github/akimd/bison/jobs/687812428.
    - name: "PPC64le: GCC 9 part 1"
      stage: check
      os: linux
      arch: ppc64le
      dist: bionic
-      addons: *gcc9
+      addons: *gcc10
      env:
        - CC=gcc-9
        - CXX=g++-9
        - CONFIGUREFLAGS='CFLAGS=-O3 CXXFLAGS=-O3'
        - PART=1

-    - name: "s390x: GCC 9 part 1"
+    - name: "s390x: GCC 10 part 1"
      stage: check
      os: linux
      arch: s390x
      dist: bionic
-      addons: *gcc9
+      addons: *gcc10
      env:
-        - CC=gcc-9
-        - CXX=g++-9
+        - CC=gcc-10
+        - CXX=g++-10
        - CONFIGUREFLAGS='CFLAGS=-O3 CXXFLAGS=-O3'
        - PART=1

@@ -182,15 +177,19 @@ jobs:
    ## GCC.  ##
    ## ----- ##

-    - name: "GCC 8 with sanitizers part 1"
+    - name: "GCC 9 with sanitizers part 1"
+      stage: check
      os: linux
      dist: bionic
      addons:
        apt:
-          packages: g++-8
+          sources:
+            # See https://github.com/travis-ci/apt-source-safelist/issues/410.
+            - sourceline: 'ppa:ubuntu-toolchain-r/test'
+          packages: g++-9
      env:
-        - CC='gcc-8 -fsanitize=undefined,address -fno-omit-frame-pointer'
-        - CXX='g++-8 -fsanitize=undefined,address -fno-omit-frame-pointer'
+        - CC='gcc-9 -fsanitize=undefined,address -fno-omit-frame-pointer'
+        - CXX='g++-9 -fsanitize=undefined,address -fno-omit-frame-pointer'
        - CONFIGUREFLAGS='CFLAGS=-O1 CXXFLAGS=-O1'
        - PART=1

@@ -292,7 +291,27 @@ jobs:
    ## Clang.  ##
    ## ------- ##

-    - name: "Clang 8 -O3"
+    - name: "Clang 9 -O3"
+      stage: check
+      os: linux
+      dist: bionic
+      addons:
+        apt:
+          sources:
+            # See https://github.com/travis-ci/apt-source-safelist/issues/410.
+            - sourceline: 'ppa:ubuntu-toolchain-r/test'
+            - sourceline: 'deb http://apt.llvm.org/bionic/ llvm-toolchain-bionic-9 main'
+              key_url: 'https://apt.llvm.org/llvm-snapshot.gpg.key'
+          packages:
+            - clang-9
+            - libc++-9-dev
+            - libc++abi-9-dev
+      env:
+        - CC='clang-9'
+        - CXX='clang++-9 -stdlib=libc++'
+        - CONFIGUREFLAGS='CPPFLAGS=-DNDEBUG CFLAGS=-O3 CXXFLAGS=-O3'
+
+    - name: "Clang 8"
      stage: check
      os: linux
      dist: bionic
@@ -305,7 +324,6 @@ jobs:
      env:
        - CC=clang-8
        - CXX='clang++-8 -stdlib=libc++'
-        - CONFIGUREFLAGS='CPPFLAGS=-DNDEBUG CFLAGS=-O3 CXXFLAGS=-O3'

    - name: "Clang 7"
      stage: check
@@ -127,3 +127,7 @@ gen-ChangeLog:
 	    --since=$(gen_start_date) > $$cl.tmp &&	\
 	  mv -f $$cl.tmp $$cl;				\
 	fi
+
+# Useful to debug.
+.c.i:
+	$(CC) $(AM_CPPFLAGS) $(CPPFLAGS) $(AM_CFLAGS) $(CFLAGS) -o $@ -E $<
@@ -1,6 +1,32 @@
 GNU Bison NEWS

-* Noteworthy changes in release 3.5.90 (2020-04-18) [beta]
+* Noteworthy changes in release 3.6.2 (2020-05-17) [stable]
+
+** Bug fixes
+
+  Some tests were fixed.
+
+  When token aliases contain comment delimiters:
+
+    %token FOO "/* foo */"
+
+  bison used to emit "nested" comments, which is invalid C.
+
+* Noteworthy changes in release 3.6.1 (2020-05-10) [stable]
+
+** Bug fixes
+
+  Restored ANSI-C compliance in yacc.c.
+
+  GNU readline portability issues.
+
+  In C++, yy::parser::symbol_name is now a public member, as was intended.
+
+** New features
+
+  In C++, yy::parser::symbol_type now has a public name() member function.
+
+* Noteworthy changes in release 3.6 (2020-05-08) [stable]

 ** Backward incompatible changes

@@ -14,6 +40,12 @@ GNU Bison NEWS
  (2013-07-25), "%error-verbose" is deprecated in favor of "%define
  parse.error verbose".

+** Deprecated features
+
+  The YYPRINT macro, which works only with yacc.c and only for tokens, was
+  obsoleted long ago by %printer, introduced in Bison 1.50 (November 2002).
+  It is deprecated and its support will be removed eventually.
+
 ** New features

 *** Improved syntax error messages
@@ -80,7 +112,7 @@ GNU Bison NEWS
        PLUS   "+"
        MINUS  "-"
      <double>
-        NUM _("double precision number")
+        NUM _("number")
      <symrec*>
        FUN _("function")
        VAR _("variable")
@@ -99,6 +131,18 @@ GNU Bison NEWS
  It makes little sense to use this feature without enabling LAC (lookahead
  correction).

+*** Returning the error token
+
+  When the scanner returns an invalid token or the undefined token
+  (YYUNDEF), the parser generates an error message and enters error
+  recovery.  Because of that error message, most scanners that find lexical
+  errors generate an error message, and then ignore the invalid input
+  without entering the error-recovery.
+
+  The scanners may now return YYerror, the error token, to enter the
+  error-recovery mode without triggering an additional error message.  See
+  the bistromathic for an example.
+
 *** Deep overhaul of the symbol and token kinds

  To avoid the confusion with types in programming languages, we now refer
@@ -117,10 +161,10 @@ GNU Bison NEWS
  "yytoken_kind_t".

  This type now also includes tokens that were previously hidden: YYEOF (end
-  of input), YYUNDEF (undefined token), and YYERRCODE (error token).  They
+  of input), YYUNDEF (undefined token), and YYerror (error token).  They
  now have string aliases, internationalized when internationalization is
  enabled.  Therefore, by default, error messages now refer to "end of file"
-  (internationalized) rather than the cryptic "$end", or to "invaid token"
+  (internationalized) rather than the cryptic "$end", or to "invalid token"
  rather than "$undefined".

  Therefore in most cases it is now useless to define the end-of-line token
@@ -186,8 +230,8 @@ GNU Bison NEWS

 *** Examples

-  There are now two examples in examples/java: a very simple calculator, and
-  one that tracks locations to provide accurate error messages.
+  There are now examples/java: a very simple calculator, and a more complete
+  one (push-parser, location tracking, and debug traces).

  The lexcalc example (a simple example in C based on Flex and Bison) now
  also demonstrates location tracking.
@@ -2518,7 +2562,7 @@ GNU Bison NEWS
  Running "make install-pdf" (or -dvi, -html, -info, and -ps) no longer
  halts in the middle of its course.

-* Changes in version 2.5 (2011-05-14):
+* Noteworthy changes in release 2.5 (2011-05-14)

 ** Grammar symbol names can now contain non-initial dashes:

@@ -2873,7 +2917,7 @@ GNU Bison NEWS

  This bug has been fixed.

-* Changes in version 2.4.3 (2010-08-05):
+* Noteworthy changes in release 2.4.3 (2010-08-05)

 ** Bison now obeys -Werror and --warnings=error for warnings about
   grammar rules that are useless in the parser due to conflicts.
@@ -2893,7 +2937,7 @@ GNU Bison NEWS

 ** Minor documentation fixes.

-* Changes in version 2.4.2 (2010-03-20):
+* Noteworthy changes in release 2.4.2 (2010-03-20)

 ** Some portability problems that resulted in failures and livelocks
   in the test suite on some versions of at least Solaris, AIX, HP-UX,
@@ -2987,7 +3031,7 @@ GNU Bison NEWS
  message translations were not installed although supported by the
  host system.

-* Changes in version 2.4.1 (2008-12-11):
+* Noteworthy changes in release 2.4.1 (2008-12-11)

 ** In the GLR defines file, unexpanded M4 macros in the yylval and yylloc
   declarations have been fixed.
@@ -3012,7 +3056,7 @@ GNU Bison NEWS

 ** A few minor improvements to the Bison manual.

-* Changes in version 2.4 (2008-11-02):
+* Noteworthy changes in release 2.4 (2008-11-02)

 ** %language is an experimental feature.

@@ -3027,7 +3071,7 @@ GNU Bison NEWS
 ** Several bugs in the C++ skeleton and the experimental Java skeleton have been
  fixed.

-* Changes in version 2.3b (2008-05-27):
+* Noteworthy changes in release 2.3b (2008-05-27)

 ** The quotes around NAME that used to be required in the following directive
  are now deprecated:
@@ -3213,7 +3257,7 @@ GNU Bison NEWS
 ** The nonfunctional --no-parser, -n, and %no-parser options have been
  completely removed from Bison.

-* Changes in version 2.3a, 2006-09-13:
+* Noteworthy changes in release 2.3a (2006-09-13)

 ** Instead of %union, you can define and use your own union type
  YYSTYPE if your grammar contains at least one <type> tag.
@@ -3327,7 +3371,7 @@ GNU Bison NEWS
  The old spelling still works, but is not documented and may be removed
  in a future release.

-* Changes in version 2.3, 2006-06-05:
+* Noteworthy changes in release 2.3 (2006-06-05)

 ** GLR grammars should now use "YYRECOVERING ()" instead of "YYRECOVERING",
  for compatibility with LALR(1) grammars.
@@ -3335,7 +3379,7 @@ GNU Bison NEWS
 ** It is now documented that any definition of YYSTYPE or YYLTYPE should
  be to a type name that does not contain parentheses or brackets.

-* Changes in version 2.2, 2006-05-19:
+* Noteworthy changes in release 2.2 (2006-05-19)

 ** The distribution terms for all Bison-generated parsers now permit
  using the parsers in nonfree programs.  Previously, this permission
@@ -3417,7 +3461,7 @@ GNU Bison NEWS

 ** DJGPP support added.

-* Changes in version 2.1, 2005-09-16:
+* Noteworthy changes in release 2.1 (2005-09-16)

 ** The C++ lalr1.cc skeleton supports %lex-param.

@@ -3443,7 +3487,7 @@ GNU Bison NEWS
  print 'syntax error, unexpected number' instead of 'syntax error,
  unexpected "number"'.

-* Changes in version 2.0, 2004-12-25:
+* Noteworthy changes in release 2.0 (2004-12-25)

 ** Possibly-incompatible changes

@@ -3506,7 +3550,7 @@ GNU Bison NEWS

  - Semicolons are now allowed before "|" in grammar rules, as POSIX requires.

-* Changes in version 1.875, 2003-01-01:
+* Noteworthy changes in release 1.875 (2003-01-01)

 ** The documentation license has been upgraded to version 1.2
  of the GNU Free Documentation License.
@@ -3626,7 +3670,7 @@ GNU Bison NEWS
  ago, but nobody noticed until we recently asked someone to try
  building Bison with a K&R C compiler.

-* Changes in version 1.75, 2002-10-14:
+* Noteworthy changes in release 1.75 (2002-10-14)

 ** Bison should now work on 64-bit hosts.

@@ -3657,7 +3701,7 @@ GNU Bison NEWS
  was incorrectly rejected: $1 is defined in the second midrule
  action, and is equal to the $$ of the first midrule action.

-* Changes in version 1.50, 2002-10-04:
+* Noteworthy changes in release 1.50 (2002-10-04)

 ** GLR parsing
  The declaration
@@ -3801,7 +3845,7 @@ GNU Bison NEWS

 ** GNU M4 is now required when using Bison.

-* Changes in version 1.35, 2002-03-25:
+* Noteworthy changes in release 1.35 (2002-03-25)

 ** C Skeleton
  Some projects use Bison's C parser with C++ compilers, and define
@@ -3816,7 +3860,7 @@ GNU Bison NEWS
  This kludge also addresses some C++ problems when the stack was
  extended.

-* Changes in version 1.34, 2002-03-12:
+* Noteworthy changes in release 1.34 (2002-03-12)

 ** File name clashes are detected
  $ bison foo.y -d -o foo.x
@@ -3836,7 +3880,7 @@ GNU Bison NEWS

 ** Fix test suite portability problems.

-* Changes in version 1.33, 2002-02-07:
+* Noteworthy changes in release 1.33 (2002-02-07)

 ** Fix C++ issues
  Groff could not be compiled for the definition of size_t was lacking
@@ -3845,7 +3889,7 @@ GNU Bison NEWS
 ** Catch invalid @n
  As is done with $n.

-* Changes in version 1.32, 2002-01-23:
+* Noteworthy changes in release 1.32 (2002-01-23)

 ** Fix Yacc output file names

@@ -3853,7 +3897,7 @@ GNU Bison NEWS

 ** Italian, Dutch translations

-* Changes in version 1.31, 2002-01-14:
+* Noteworthy changes in release 1.31 (2002-01-14)

 ** Many Bug Fixes

@@ -3940,7 +3984,7 @@ GNU Bison NEWS
 ** --output
  New, aliasing "--output-file".

-* Changes in version 1.30, 2001-10-26:
+* Noteworthy changes in release 1.30 (2001-10-26)

 ** "--defines" and "--graph" have now an optional argument which is the
  output file name. "-d" and "-g" do not change; they do not take any
@@ -3951,7 +3995,7 @@ GNU Bison NEWS

 ** Portability fixes.

-* Changes in version 1.29, 2001-09-07:
+* Noteworthy changes in release 1.29 (2001-09-07)

 ** The output file does not define const, as this caused problems when used
  with common autoconfiguration schemes.  If you still use ancient compilers
@@ -3986,7 +4030,7 @@ GNU Bison NEWS
 ** @$
  Automatic location tracking.

-* Changes in version 1.28, 1999-07-06:
+* Noteworthy changes in release 1.28 (1999-07-06)

 ** Should compile better now with K&R compilers.

@@ -3996,12 +4040,12 @@ GNU Bison NEWS

 ** There is now a FAQ.

-* Changes in version 1.27:
+* Noteworthy changes in release 1.27

 ** The make rule which prevented bison.simple from being created on
  some systems has been fixed.

-* Changes in version 1.26:
+* Noteworthy changes in release 1.26

 ** Bison now uses Automake.

@@ -4018,7 +4062,7 @@ GNU Bison NEWS
 ** Generated parsers should now work even on operating systems which do
  not provide alloca().

-* Changes in version 1.25, 1995-10-16:
+* Noteworthy changes in release 1.25 (1995-10-16)

 ** Errors in the input grammar are not fatal; Bison keeps reading
 the grammar file, and reports all the errors found in it.
@@ -4043,7 +4087,7 @@ the parser engine; a project can now use its own parser engine.
 The actions go into a separate file called NAME.act, in the form of
 a switch statement body.

-* Changes in version 1.23:
+* Noteworthy changes in release 1.23

 The user can define YYPARSE_PARAM as the name of an argument to be
 passed into yyparse.  The argument should have type void *.  It should
@@ -4052,11 +4096,11 @@ by casting it to the proper pointer type.

 Line numbers in output file corrected.

-* Changes in version 1.22:
+* Noteworthy changes in release 1.22

 --help option added.

-* Changes in version 1.20:
+* Noteworthy changes in release 1.20

 Output file does not redefine const for C++.

@@ -4113,8 +4157,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 LocalWords:  fsanitize Vogelsgesang lis redeclared stdint automata yytname
 LocalWords:  yysymbol yytnamerr yyreport ctx ARGMAX yysyntax stderr LPAREN
 LocalWords:  symrec yypcontext TOKENMAX yyexpected YYEMPTY yypstate YYEOF
- LocalWords:  autocompletion bistromathic submessages Cayuela lexcalc
- LocalWords:  yytoken YYUNDEF YYERRCODE
+ LocalWords:  autocompletion bistromathic submessages Cayuela lexcalc hoc
+ LocalWords:  yytoken YYUNDEF YYerror

 Local Variables:
 ispell-dictionary: "american"
@@ -37,6 +37,14 @@ Only user visible strings are to be translated: error messages, bits of the
 assert/abort), and all the --trace output which is meant for the maintainers
 only.

+## Syntax highlighting
+It's quite nice to be in C++ mode when editing lalr1.cc for instance.
+However tools such as Emacs will be fooled by the fact that braces and
+parens do not nest, as in `[[}]]`.  As a consequence you might be misguided
+by its visual pairing to parens.  The m4-mode is safer.  Unfortunately the
+m4-mode is also fooled by `#` which is sees as a comment, stops pairing with
+parens/brackets that are inside...
+
 ## Coding Style
 Do not add horizontal tab characters to any file in Bison's repository
 except where required.  For example, do not use tabs to format C code.
@@ -57,6 +65,31 @@ Actually, Bison has legacy code that we should replace with gnulib modules
 ### Skeletons
 We try to use the "typical" coding style for each language.

+#### CPP
+We indent the CPP directives this way:
+
+```
+#if FOO
+# if BAR
+#  define BAZ
+# endif
+#endif
+```
+
+Don't indent with leading spaces in the skeletons (it's ok in the grammar
+files though, e.g., in `%code {...}` blocks).
+
+On occasions, use `cppi -c` to see where we stand.  We don't aim at full
+correctness: depending `-d`, some bits can be in the *.c file, or the *.h
+file within the double-inclusion cpp-guards.  In that case, favor the case
+of the *.h file, but don't waste time on this.
+
+Don't hesitate to leave a comment on the `#endif` (e.g., `#endif /* FOO
+*/`), especially for long blocks.
+
+There is no conistency on `! defined` vs. `!defined`.  The day gnulib
+decides, we'll follow them.
+
 #### C/C++
 Follow the GNU Coding Standards.

@@ -370,6 +403,12 @@ again, since some early failures may stop latter tests from being run.  Yet
 at some point, you'll have to fix remaining issues by hand...


+## Running Java parsers
+Use the `javaexec.sh` script.  For instance to run the parser of test case
+504:
+
+    $ sh ./_build/javaexec.sh -cp ./_build/tests/testsuite.dir/504 Calc
+
 ## make maintainer-check-valgrind
 This target uses valgrind both to check bison, and the generated parsers.

@@ -20,6 +20,7 @@ Anthony Heading           [email protected]
 Antonio Silva Correia     [email protected]
 Arnold Robbins            [email protected]
 Art Haas                  [email protected]
+Arthur Schwarz            [email protected]
 Askar Safin               [email protected]
 Balázs Scheidler          [email protected]
 Baron Schwartz            [email protected]
@@ -57,6 +58,7 @@ Derek M. Jones            [email protected]
 Di-an Jan                 [email protected]
 Dick Streefland           [email protected]
 Didier Godefroy           [email protected]
+Don Macpherson            [email protected]
 Efi Fogel                 [email protected]
 Enrico Scholz             [email protected]
 Eric Blake                [email protected]
@@ -154,6 +156,7 @@ Petr Machata              [email protected]
 Pho                       [email protected]
 Piotr Gackiewicz          [email protected]
 Piotr Marcińczyk          [email protected]
+Pramod Kumbhar            [email protected]
 Quentin Hocquet           [email protected]
 Quoc Peyrot               [email protected]
 R Blake                   [email protected]
@@ -1,4 +1,15 @@
-* Bison 3.6
+* Bison 3.7
+** Bistromathic
+- Hitting tab on a line with a syntax error is ugly
+
+- Be robust to existing ~/.inputrc
+
+- How about not evaluating incomplete lines when the text is not finished
+  (as shells do).
+
+** Doc
+*** api.header.include
+
 ** Questions
 *** Java
 - Should i18n be part of the Lexer?  Currently it's a static method of
@@ -7,6 +18,10 @@
 - is there a migration path that would allow to use TokenKinds in
  yylex?

+- define the tokens as an enum too.
+
+- promote YYEOF rather than EOF.
+
 *** D
 - is there a way to attach yysymbol_name to the enum itself?  As we did
  in Java.
@@ -14,17 +29,37 @@
 - It would be better to have TokenKind as return value.  Can we use
  reflection to support both output types?

-** Documentation
- YYERRCODE, YYUNDEF, YYEOF
- YYERRCODE and translation
+** YYerror
+https://git.savannah.gnu.org/gitweb/?p=gettext.git;a=blob;f=gettext-runtime/intl/plural.y;h=a712255af4f2f739c93336d4ff6556d932a426a5;hb=HEAD
+
+should be updated to not use YYERRCODE.  Returning an undef token is good
+enough.

 ** Java
-*** Examples
-Have an example with a push parser.  Use autocompletion in that case.
-
 *** calc.at
 Stop hard-coding "Calc".  Adjust local.at (look for FIXME).

+** Counter example generation
+See https://github.com/akimd/bison/pull/15.
+
+** Clean up
+Rename user_token_number for tokens as "code".  It's not a "user number",
+it's the token code, and the user can control it, but this code always
+exists.
+
+See also USER_NUMBER_UNDEFINED and NUMBER_UNDEFINED.
+
+Rename endtoken as eoftoken.
+
+Also do it in data/skeletons.
+
+Don't rename in Bison 3.6 (it would be logical to do so) because that
+would probably create many conflicts in Vincent's work (see previous point).
+
+** A dev warning for b4_
+Maybe we should check for m4_ and b4_ leaking out of the m4 processing, as
+Autoconf does.  It would have caught overquotation issues.
+
 ** doc
 I feel it's ugly to use the GNU style to declare functions in the doc.  It
 generates tons of white space in the page, and may contribute to bad page
@@ -35,7 +70,7 @@ token vs terminal, variable vs non terminal.

 ** api.token.raw
 The YYUNDEFTOK could be assigned a semantic value so that yyerror could be
-used to report invalid lexemes.  See also the item "$undefined" below.
+used to report invalid lexemes.

 ** push parsers
 Consider deprecating impure push parsers.  They add a lot of complexity, for
@@ -43,21 +78,74 @@ a bad feature.  On the other hand, that would make it much harder to sit
 push parsers on top of pull parser.  Which is currently not relevant, since
 push parsers are measurably slower.

-* Bison 3.7
-** Counter example generation
-See https://github.com/akimd/bison/pull/15.
+** %define parse.error formatted
+How about pushing bistromathics' yyreport_syntax_error as another standard
+way to generate the error message, and leave to the user the task of
+providing the message formats?  Currently in bistro, it reads:

-** Clean up
-Rename user_token_number for tokens as "code".  It's not a "user number",
-it's the token code, and the user can control it, but this code always
-exists.
+    const char *
+    error_format_string (int argc)
+    {
+      switch (argc)
+        {
+        default: /* Avoid compiler warnings. */
+        case 0: return _("%@: syntax error");
+        case 1: return _("%@: syntax error: unexpected %u");
+          // TRANSLATORS: '%@' is a location in a file, '%u' is an
+          // "unexpected token", and '%0e', '%1e'... are expected tokens
+          // at this point.
+          //
+          // For instance on the expression "1 + * 2", you'd get
+          //
+          // 1.5: syntax error: expected - or ( or number or function or variable before *
+        case 2: return _("%@: syntax error: expected %0e before %u");
+        case 3: return _("%@: syntax error: expected %0e or %1e before %u");
+        case 4: return _("%@: syntax error: expected %0e or %1e or %2e before %u");
+        case 5: return _("%@: syntax error: expected %0e or %1e or %2e or %3e before %u");
+        case 6: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e before %u");
+        case 7: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e or %5e before %u");
+        case 8: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e or %5e or %6e before %u");
+        }
+    }

-Rename endtoken as eoftoken.
+The message would have to be generated in a string, and pushed to yyerror.
+Which will be a pain in the neck in yacc.c.

-Also do it in data/skeletons.
+If we want to do that, we should think very carefully about the syntax of
+the format string.

-Don't rename in Bison 3.6 (it would be logical to do so) because that
-would probably create many conflicts in Vincent's work (see previous point).
+** yyclearin does not invoke the lookahead token's %destructor
+https://lists.gnu.org/r/bug-bison/2018-02/msg00000.html
+Rici:
+
+> Modifying yyclearin so that it calls yydestruct seems like the simplest
+> solution to this issue, but it is conceivable that such a change would
+> break programs which already perform some kind of workaround in order to
+> destruct the lookahead symbol. So it might be necessary to use some kind of
+> compatibility %define, or to create a new replacement macro with a
+> different name such as yydiscardin.
+>
+> At a minimum, the fact that yyclearin does not invoke the %destructor
+> should be highlighted in the documentation, since it is not at all obvious.
+
+** Issues in i18n
+
+Les catégories d'avertissements incluent :
+  conflicts-sr      conflits S/R (activé par défaut)
+  conflicts-rr      conflits R/R (activé par défaut)
+  dangling-alias    l'alias chaîne n'est pas attaché à un symbole
+  deprecated        construction obsolète
+  empty-rule        règle vide sans %empty
+  midrule-values    valeurs de règle intermédiaire non définies ou inutilisées
+  precedence        priorité et associativité inutiles
+  yacc              incompatibilités avec POSIX Yacc
+  other             tous les autres avertissements (activé par défaut)
+  all               tous les avertissements sauf « dangling-alias » et « yacc »
+  no-CATEGORY       désactiver les avertissements dans CATEGORIE
+  none              désactiver tous les avertissements
+  error[=CATEGORY]  traiter les avertissements comme des erreurs
+
+Line -1 and -3 should mention CATEGORIE, not CATEGORY.

 * Bison 3.8
 ** Unit rules / Injection rules (Akim Demaille)
@@ -133,10 +221,10 @@ define it to the same type as the C ptrdiff_t type.
 * Completion
 Several features are not available in all the backends.

- push parsers: glr.c, glr.cc, lalr1.cc
- lac: D, Java
- glr: D, Java
- token constructors: Java, C, D
+- lac: D, Java (easy)
+- push parsers: glr.c, glr.cc, lalr1.cc (not very difficult)
+- token constructors: Java, C, D (a bit difficult)
+- glr: D, Java (super difficult)

 * Bugs
 ** Autotest has quotation issues
@@ -340,8 +428,12 @@ LORIA, INRIA Nancy - Grand Est, Nancy, France
 ** More languages?
 Well, only if there is really some demand for it.

+*** PHP
 https://github.com/scfc/bison-php/blob/master/data/lalr1.php

+*** Python
+https://lists.gnu.org/r/bison-patches/2013-09/msg00000.html and following
+
 ** Multiple start symbols
 Would be very useful when parsing closely related languages.  The idea is to
 declare several start symbols, for instance
@@ -460,15 +552,6 @@ move to partial orders (sounds like series/parallel orders to me).

 This is a prerequisite for modules.

-* $undefined
-From Hans:
- If the Bison generated parser experiences an undefined number in the
-character range, that character is written out in diagnostic messages, an
-addition to the $undefined value.
-
-Suggest: Change the name $undefined to undefined; looks better in outputs.
-
-
 * Pre and post actions.
 From: Florian Krohm <[email protected]>
 Subject: YYACT_EPILOGUE
@@ -73,6 +73,11 @@ def diff_to_re(match):
            is_diff = True
            to.append(l)
    if is_diff:
+        # Do not run s//SOMETHING/g (with an emty pattern), that won't
+        # work well...
+        if frm == []:
+            trace("no from for", match.group(1))
+            return
        frm = "\n".join(frm)
        to = "\n".join(to)
        subst[frm] = to
@@ -112,4 +117,6 @@ def process(logfile):

 for logfile in args.logs:
    trace("FILE:", logfile)
+    if os.path.isdir(logfile):
+        logfile = os.path.join(logfile, 'testsuite.log')
    process(logfile)
@@ -51,7 +51,7 @@ gnulib_dir = $(srcdir)/gnulib
 bootstrap-tools = autoconf,automake,flex,gettext,gnulib

 announcement_Cc_ = \
-  [email protected], [email protected], bison-patches@gnu.org, \
+  [email protected], bison-announce@gnu.org, \
  [email protected]

 update-copyright: update-b4-copyright update-package-copyright-year
@@ -156,7 +156,7 @@ exclude = \
 $(call exclude,                                                                 \
  bindtextdomain=^lib/main.c$$                                                  \
  cast_of_argument_to_free=^src/muscle-tab.c$$                                  \
-  po_check=^(examples|tests)/|(^po/POTFILES.in|.md)$$                           \
+  po_check=^tests|(^po/POTFILES.in|.md)$$                                       \
  preprocessor_indentation=^data/|^lib/|^src/parse-gram.[ch]$$                  \
  program_name=^lib/main.c$$                                                    \
  prohibit_always-defined_macros=^data/skeletons/yacc.c$$                       \
@@ -36,10 +36,8 @@ AC_DEFINE_UNQUOTED([PACKAGE_COPYRIGHT_YEAR], [$PACKAGE_COPYRIGHT_YEAR],
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_MACRO_DIR([m4])

-# We use Automake 1.14's %D% and %C%.
-#
 # When we move to Automake 1.16, simplify examples/c/reccalc/local.mk.
-# Our CI runs on Xenial, which has only Automake 1.15.
+# Our CI build the packages on Bionic, which has only Automake 1.15.
 #
 # We want gnits strictness only when rolling a stable release.  For
 # release candidates, we use version strings like 2.4.3_rc1, but gnits
@@ -47,7 +45,7 @@ AC_CONFIG_MACRO_DIR([m4])
 # releases, we want to be able run make dist without being required to
 # add a bogus NEWS entry.  In that case, the version string
 # automatically contains a dash, which we also let disable gnits.
-AM_INIT_AUTOMAKE([1.14 dist-xz nostdinc
+AM_INIT_AUTOMAKE([1.15 dist-lzip dist-xz nostdinc
                 color-tests parallel-tests
                 silent-rules]
                 m4_bmatch(m4_defn([AC_PACKAGE_VERSION]), [[-_]],
@@ -261,9 +259,9 @@ if ! "$LEX_IS_FLEX" || test "X$LEX" = X:; then
  AC_MSG_WARN([bypassing lex because flex is required])
  LEX=:
 fi
-AM_CONDITIONAL([FLEX_WORKS], [$LEX_IS_FLEX])
+AM_CONDITIONAL([FLEX_WORKS], [$LEX_IS_FLEX && $FLEX_SUPPORTS_HEADER_OPT])
 AM_CONDITIONAL([FLEX_CXX_WORKS],
-  [$LEX_IS_FLEX && test $bison_cv_cxx_works = yes])
+  [$LEX_IS_FLEX && $FLEX_SUPPORTS_HEADER_OPT && test $bison_cv_cxx_works = yes])
 AC_PROG_YACC
 AC_PROG_RANLIB
 AC_PROG_GNU_M4
@@ -332,6 +330,13 @@ AC_MSG_RESULT([$suppfile])
 # Whether we cannot run the compiled bison.
 AM_CONDITIONAL([CROSS_COMPILING], [test "$cross_compiling" = yes])

+# Build bistromathic if we have the lib and both readline/readline.h
+# and readline/history.h.
+AM_CONDITIONAL([ENABLE_BISTROMATHIC],
+[test "$gl_cv_lib_readline" != no &&
+  test "$ac_cv_header_readline_readline_h" = yes &&
+  test "$ac_cv_header_readline_history_h" = yes])
+
 AM_MISSING_PROG([AUTOM4TE], [autom4te])
 # Needed by tests/atlocal.in.
 AC_SUBST([GCC])
@@ -72,8 +72,9 @@ version 2.2 of Bison.])
 # -------------
 # Issue a warning about private implementation details.
 m4_define([b4_disclaimer],
-[b4_comment([Undocumented macros, especially those whose name start with YY_,
-are private implementation details.  Do not rely on them.])
+[b4_comment([DO NOT RELY ON FEATURES THAT ARE NOT DOCUMENTED in the manual,
+especially those whose name start with YY_ or yy_.  They are
+private implementation details that can be changed or removed.])
 ])


@@ -369,6 +370,7 @@ m4_define([b4_$3_if],
 # Expand IF-TRUE, if FLAG is true, IF-FALSE otherwise.
 b4_define_flag_if([defines])            # Whether headers are requested.
 b4_define_flag_if([glr])                # Whether a GLR parser is requested.
+b4_define_flag_if([has_translations])   # Whether some tokens are internationalized.
 b4_define_flag_if([nondeterministic])   # Whether conflicts should be handled.
 b4_define_flag_if([token_table])        # Whether yytoken_table is demanded.
 b4_define_flag_if([yacc])               # Whether POSIX Yacc is emulated.
@@ -425,7 +427,7 @@ m4_define([b4_symbol_kind],
 m4_case([$1],
  [-2],                             [[YYEMPTY]],
  [0],                              [[YYEOF]],
-  [1],                              [[YYERROR]],
+  [1],                              [[YYerror]],
  [2],                              [[YYUNDEF]],
  [m4_case(b4_symbol([$1], [tag]),
      [$accept],                    [[YYACCEPT]],
@@ -259,14 +259,14 @@ m4_define([b4_public_types_declare],
    struct token
    {
      ]b4_token_enums[
-      /// Backward compatibility alias.
+      /// Backward compatibility alias (Bison 3.6).
      typedef token_kind_type yytokentype;
    };

    /// Token kind, as returned by yylex.
    typedef token::yytokentype token_kind_type;

-    /// Backward compatibility alias.
+    /// Backward compatibility alias (Bison 3.6).
    typedef token_kind_type token_type;

    /// Symbol kinds.
@@ -352,12 +352,35 @@ m4_define([b4_symbol_type_define],
          break;
        }

-        // Type destructor.
+        // Value type destructor.
 ]b4_symbol_variant([[yykind]], [[value]], [[template destroy]])])[
        Base::clear ();
      }

-      /// Backward compatibility.
+]b4_parse_error_bmatch(
+[custom\|detailed],
+[[      /// The user-facing name of this symbol.
+      const char *name () const YY_NOEXCEPT
+      {
+        return ]b4_parser_class[::symbol_name (this->kind ());
+      }]],
+[simple],
+[[#if ]b4_api_PREFIX[DEBUG || ]b4_token_table_flag[
+      /// The user-facing name of this symbol.
+      const char *name () const YY_NOEXCEPT
+      {
+        return ]b4_parser_class[::symbol_name (this->kind ());
+      }
+#endif // #if ]b4_api_PREFIX[DEBUG || ]b4_token_table_flag[
+]],
+[verbose],
+[[      /// The user-facing name of this symbol.
+      std::string name () const YY_NOEXCEPT
+      {
+        return ]b4_parser_class[::symbol_name (this->kind ());
+      }]])[
+
+      /// Backward compatibility (Bison 3.6).
      symbol_kind_type type_get () const YY_NOEXCEPT;

      /// Whether empty.
@@ -380,45 +403,51 @@ m4_define([b4_symbol_type_define],
    };

    /// Type access provider for token (enum) based symbols.
-    struct by_type
+    struct by_kind
    {
      /// Default constructor.
-      by_type ();
+      by_kind ();

 #if 201103L <= YY_CPLUSPLUS
      /// Move constructor.
-      by_type (by_type&& that);
+      by_kind (by_kind&& that);
 #endif

      /// Copy constructor.
-      by_type (const by_type& that);
+      by_kind (const by_kind& that);

      /// The symbol kind as needed by the constructor.
      typedef token_kind_type kind_type;

      /// Constructor from (external) token numbers.
-      by_type (kind_type t);
+      by_kind (kind_type t);

      /// Record that this symbol is empty.
      void clear ();

      /// Steal the symbol kind from \a that.
-      void move (by_type& that);
+      void move (by_kind& that);

      /// The (internal) type number (corresponding to \a type).
      /// \a empty when empty.
      symbol_kind_type kind () const YY_NOEXCEPT;

+      /// Backward compatibility (Bison 3.6).
+      symbol_kind_type type_get () const YY_NOEXCEPT;
+
      /// The symbol kind.
      /// \a ]b4_symbol_prefix[YYEMPTY when empty.
-      symbol_kind_type type;
+      symbol_kind_type kind_;
    };

+    /// Backward compatibility for a private implementation detail (Bison 3.6).
+    typedef by_kind by_type;
+
    /// "External" symbols: returned by the scanner.
-    struct symbol_type : basic_symbol<by_type>
+    struct symbol_type : basic_symbol<by_kind>
    {]b4_variant_if([[
      /// Superclass.
-      typedef basic_symbol<by_type> super_type;
+      typedef basic_symbol<by_kind> super_type;

      /// Empty symbol.
      symbol_type () {}
@@ -492,44 +521,50 @@ m4_define([b4_public_types_define],
    location = YY_MOVE (s.location);])[
  }

-  // by_type.
-  ]b4_inline([$1])b4_parser_class[::by_type::by_type ()
-    : type (symbol_kind::]b4_symbol_prefix[YYEMPTY)
+  // by_kind.
+  ]b4_inline([$1])b4_parser_class[::by_kind::by_kind ()
+    : kind_ (symbol_kind::]b4_symbol_prefix[YYEMPTY)
  {}

 #if 201103L <= YY_CPLUSPLUS
-  ]b4_inline([$1])b4_parser_class[::by_type::by_type (by_type&& that)
-    : type (that.type)
+  ]b4_inline([$1])b4_parser_class[::by_kind::by_kind (by_kind&& that)
+    : kind_ (that.kind_)
  {
    that.clear ();
  }
 #endif

-  ]b4_inline([$1])b4_parser_class[::by_type::by_type (const by_type& that)
-    : type (that.type)
+  ]b4_inline([$1])b4_parser_class[::by_kind::by_kind (const by_kind& that)
+    : kind_ (that.kind_)
  {}

-  ]b4_inline([$1])b4_parser_class[::by_type::by_type (token_kind_type t)
-    : type (yytranslate_ (t))
+  ]b4_inline([$1])b4_parser_class[::by_kind::by_kind (token_kind_type t)
+    : kind_ (yytranslate_ (t))
  {}

  ]b4_inline([$1])[void
-  ]b4_parser_class[::by_type::clear ()
+  ]b4_parser_class[::by_kind::clear ()
  {
-    type = symbol_kind::]b4_symbol_prefix[YYEMPTY;
+    kind_ = symbol_kind::]b4_symbol_prefix[YYEMPTY;
  }

  ]b4_inline([$1])[void
-  ]b4_parser_class[::by_type::move (by_type& that)
+  ]b4_parser_class[::by_kind::move (by_kind& that)
  {
-    type = that.type;
+    kind_ = that.kind_;
    that.clear ();
  }

  ]b4_inline([$1])[]b4_parser_class[::symbol_kind_type
-  ]b4_parser_class[::by_type::kind () const YY_NOEXCEPT
+  ]b4_parser_class[::by_kind::kind () const YY_NOEXCEPT
  {
-    return type;
+    return kind_;
+  }
+
+  ]b4_inline([$1])[]b4_parser_class[::symbol_kind_type
+  ]b4_parser_class[::by_kind::type_get () const YY_NOEXCEPT
+  {
+    return this->kind ();
  }
 ]])

@@ -22,10 +22,14 @@
 # Put TEXT in comment.  Avoid trailing spaces: don't indent empty lines.
 # Avoid adding indentation to the first line, as the indentation comes
 # from OPEN.  That's why we don't patsubst([$1], [^\(.\)], [   \1]).
+# Turn "*/" in TEXT into "* /" so that we don't unexpectedly close
+# the comments before its end.
 #
 # Prefix all the output lines with PREFIX.
 m4_define([_b4_comment],
-[$2[]m4_bpatsubst(m4_expand([[$1]]), [
+[$2[]m4_bpatsubsts(m4_expand([$1]),
+                   [[*]/], [*\\/],
+                   [/[*]], [/\\*], [
 \(.\)], [
 $3\1])$4])

@@ -205,7 +205,11 @@ m4_define([b4_c99_int_type],
 # Define private types suitable for holding small integers in C99 or later.
 m4_define([b4_c99_int_type_define],
 [m4_copy_force([b4_c99_int_type], [b4_int_type])dnl
-[/* On compilers that do not define __PTRDIFF_MAX__ etc., make sure
+[#ifdef short
+# undef short
+#endif
+
+/* On compilers that do not define __PTRDIFF_MAX__ etc., make sure
   <limits.h> and (if available) <stdint.h> are included
   so that the code can choose integer types of a good width.  */

@@ -261,6 +265,50 @@ typedef int yytype_uint16;
 #endif]])


+# b4_sizes_types_define
+# ---------------------
+# Define YYPTRDIFF_T/YYPTRDIFF_MAXIMUM, YYSIZE_T/YYSIZE_MAXIMUM,
+# and YYSIZEOF.
+m4_define([b4_sizes_types_define],
+[[#ifndef YYPTRDIFF_T
+# if defined __PTRDIFF_TYPE__ && defined __PTRDIFF_MAX__
+#  define YYPTRDIFF_T __PTRDIFF_TYPE__
+#  define YYPTRDIFF_MAXIMUM __PTRDIFF_MAX__
+# elif defined PTRDIFF_MAX
+#  ifndef ptrdiff_t
+#   include <stddef.h> /* INFRINGES ON USER NAME SPACE */
+#  endif
+#  define YYPTRDIFF_T ptrdiff_t
+#  define YYPTRDIFF_MAXIMUM PTRDIFF_MAX
+# else
+#  define YYPTRDIFF_T long
+#  define YYPTRDIFF_MAXIMUM LONG_MAX
+# endif
+#endif
+
+#ifndef YYSIZE_T
+# ifdef __SIZE_TYPE__
+#  define YYSIZE_T __SIZE_TYPE__
+# elif defined size_t
+#  define YYSIZE_T size_t
+# elif defined __STDC_VERSION__ && 199901 <= __STDC_VERSION__
+#  include <stddef.h> /* INFRINGES ON USER NAME SPACE */
+#  define YYSIZE_T size_t
+# else
+#  define YYSIZE_T unsigned
+# endif
+#endif
+
+#define YYSIZE_MAXIMUM                                  \
+  YY_CAST (YYPTRDIFF_T,                                 \
+           (YYPTRDIFF_MAXIMUM < YY_CAST (YYSIZE_T, -1)  \
+            ? YYPTRDIFF_MAXIMUM                         \
+            : YY_CAST (YYSIZE_T, -1)))
+
+#define YYSIZEOF(X) YY_CAST (YYPTRDIFF_T, sizeof (X))
+]])
+
+
 # b4_int_type_for(NAME)
 # ---------------------
 # Return a narrow int type able to handle numbers ranging from
@@ -439,7 +487,7 @@ m4_define([b4_symbol(-2, tag)], [[No symbol.]])

 m4_if(b4_symbol(0, id), [YYEOF],
     [m4_define([b4_symbol(0, id)],  [b4_api_PREFIX[][EOF]])])
-m4_define([b4_symbol(1, id)],  [b4_api_PREFIX[][ERRCODE]])
+m4_define([b4_symbol(1, id)],  [b4_api_PREFIX[][error]])
 m4_define([b4_symbol(2, id)],  [b4_api_PREFIX[][UNDEF]])


@@ -965,8 +1013,8 @@ m4_define([b4_yy_location_print_define],
   This macro was not mandated originally: define only if we know
   we won't break user code: when these are the locations we know.  */

-#ifndef YY_LOCATION_PRINT
-# if defined ]b4_api_PREFIX[LTYPE_IS_TRIVIAL && ]b4_api_PREFIX[LTYPE_IS_TRIVIAL
+# ifndef YY_LOCATION_PRINT
+#  if defined ]b4_api_PREFIX[LTYPE_IS_TRIVIAL && ]b4_api_PREFIX[LTYPE_IS_TRIVIAL

 /* Print *YYLOCP on YYO.  Private, do not rely on its existence. */

@@ -996,17 +1044,17 @@ yy_location_print_ (FILE *yyo, YYLTYPE const * const yylocp)
  return res;
 }

-#  define YY_LOCATION_PRINT(File, Loc)          \
+#   define YY_LOCATION_PRINT(File, Loc)          \
  yy_location_print_ (File, &(Loc))

-# else
-#  define YY_LOCATION_PRINT(File, Loc) ((void) 0)
-# endif
-#endif]],
+#  else
+#   define YY_LOCATION_PRINT(File, Loc) ((void) 0)
+#  endif
+# endif /* !defined YY_LOCATION_PRINT */]],
 [[/* This macro is provided for backward compatibility. */
-#ifndef YY_LOCATION_PRINT
-# define YY_LOCATION_PRINT(File, Loc) ((void) 0)
-#endif]])
+# ifndef YY_LOCATION_PRINT
+#  define YY_LOCATION_PRINT(File, Loc) ((void) 0)
+# endif]])
 ])

 # b4_yyloc_default
@@ -249,6 +249,7 @@ static YYLTYPE yyloc_default][]b4_yyloc_default;])[
 #include <string.h>

 ]b4_c99_int_type_define[
+]b4_sizes_types_define[

 #ifndef YY_
 # if defined YYENABLE_NLS && YYENABLE_NLS
@@ -261,6 +262,11 @@ static YYLTYPE yyloc_default][]b4_yyloc_default;])[
 #  define YY_(Msgid) Msgid
 # endif
 #endif
+]b4_has_translations_if([
+#ifndef N_
+# define N_(Msgid) Msgid
+#endif
+])[

 #ifndef YYFREE
 # define YYFREE free
@@ -272,9 +278,6 @@ static YYLTYPE yyloc_default][]b4_yyloc_default;])[
 # define YYREALLOC realloc
 #endif

-#define YYSIZEMAX \
-  (PTRDIFF_MAX < SIZE_MAX ? PTRDIFF_MAX : YY_CAST (ptrdiff_t, SIZE_MAX))
-
 #ifdef __cplusplus
  typedef bool yybool;
 # define yytrue true
@@ -329,10 +332,7 @@ static YYLTYPE yyloc_default][]b4_yyloc_default;])[
 #define YYMAXLEFT ]b4_max_left_semantic_context[

 /* YYMAXUTOK -- Last valid token number (for yychar).  */
-#define YYMAXUTOK   ]b4_user_token_number_max[]b4_glr_cc_if([[
-/* YYFAULTYTOK -- Token number (for yychar) that denotes a
-   syntax_error thrown from the scanner.  */
-#define YYFAULTYTOK (YYMAXUTOK + 1)]])[
+#define YYMAXUTOK   ]b4_user_token_number_max[

 /* YYTRANSLATE(TOKEN-NUM) -- Symbol number corresponding to TOKEN-NUM
   as returned by yylex, with out-of-bounds checking.  */
@@ -505,7 +505,7 @@ struct yyGLRState {
  /** Preceding state in this stack */
  yyGLRState* yypred;
  /** Source position of the last token produced by my symbol */
-  ptrdiff_t yyposn;
+  YYPTRDIFF_T yyposn;
  union {
    /** First in a chain of alternative reductions producing the
     *  nonterminal corresponding to this state, threaded through
@@ -525,8 +525,8 @@ struct yyGLRStateSet {
   *  operation, yylookaheadNeeds[0] is not maintained since it would merely
   *  duplicate yychar != ]b4_symbol(-2, id)[.  */
  yybool* yylookaheadNeeds;
-  ptrdiff_t yysize;
-  ptrdiff_t yycapacity;
+  YYPTRDIFF_T yysize;
+  YYPTRDIFF_T yycapacity;
 };

 struct yySemanticOption {
@@ -566,7 +566,7 @@ struct yyGLRStack {
  YYJMP_BUF yyexception_buffer;
  yyGLRStackItem* yyitems;
  yyGLRStackItem* yynextFree;
-  ptrdiff_t yyspaceLeft;
+  YYPTRDIFF_T yyspaceLeft;
  yyGLRState* yysplitPoint;
  yyGLRState* yylastDeleted;
  yyGLRStateSet yytops;
@@ -621,8 +621,8 @@ yysymbol_name (yysymbol_kind_t yysymbol)
  static const char *const yy_sname[] =
  {
  ]b4_symbol_names[
-  };]m4_ifdef([b4_translatable], [[
-  /* YYTRANSLATABLE[SYMBOL-NUM] -- Whether YYTNAME[SYMBOL-NUM] is
+  };]b4_has_translations_if([[
+  /* YYTRANSLATABLE[SYMBOL-NUM] -- Whether YY_SNAME[SYMBOL-NUM] is
     internationalizable.  */
  static ]b4_int_type_for([b4_translatable])[ yytranslatable[] =
  {
@@ -664,12 +664,12 @@ yysymbol_name (yysymbol_kind_t yysymbol)

 ]b4_yy_symbol_print_define[

-# define YY_SYMBOL_PRINT(Title, Type, Value, Location)                  \
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)                  \
  do {                                                                  \
    if (yydebug)                                                        \
      {                                                                 \
        YY_FPRINTF ((stderr, "%s ", Title));                            \
-        yy_symbol_print (stderr, Type, Value]b4_locuser_args([Location])[);        \
+        yy_symbol_print (stderr, Kind, Value]b4_locuser_args([Location])[);        \
        YY_FPRINTF ((stderr, "\n"));                                    \
      }                                                                 \
  } while (0)
@@ -678,7 +678,7 @@ yysymbol_name (yysymbol_kind_t yysymbol)
   multiple parsers can coexist.  */
 int yydebug;

-static void yypstack (yyGLRStack* yystackp, ptrdiff_t yyk)
+static void yypstack (yyGLRStack* yystackp, YYPTRDIFF_T yyk)
  YY_ATTRIBUTE_UNUSED;
 static void yypdumpstack (yyGLRStack* yystackp)
  YY_ATTRIBUTE_UNUSED;
@@ -686,7 +686,7 @@ static void yypdumpstack (yyGLRStack* yystackp)
 #else /* !]b4_api_PREFIX[DEBUG */

 # define YY_DPRINTF(Args) do {} while (yyfalse)
-# define YY_SYMBOL_PRINT(Title, Type, Value, Location)
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)

 #endif /* !]b4_api_PREFIX[DEBUG */

@@ -694,7 +694,7 @@ static void yypdumpstack (yyGLRStack* yystackp)
         [simple],
 [[]],
 [[#ifndef yystrlen
-# define yystrlen(S) (YY_CAST (ptrdiff_t, strlen (S)))
+# define yystrlen(S) (YY_CAST (YYPTRDIFF_T, strlen (S)))
 #endif

 ]b4_parse_error_bmatch(
@@ -729,12 +729,12 @@ yystpcpy (char *yydest, const char *yysrc)
   backslash-backslash).  YYSTR is taken from yytname.  If YYRES is
   null, do not copy; instead, return the length of what the result
   would have been.  */
-static ptrdiff_t
+static YYPTRDIFF_T
 yytnamerr (char *yyres, const char *yystr)
 {
  if (*yystr == '"')
    {
-      ptrdiff_t yyn = 0;
+      YYPTRDIFF_T yyn = 0;
      char const *yyp = yystr;

      for (;;)
@@ -825,7 +825,7 @@ yygetToken (int *yycharp][]b4_pure_if([, yyGLRStack* yystackp])[]b4_user_formals
          // Map errors caught in the scanner to the undefined token,
          // so that error handling is started.  However, record this
          // with this special value of yychar.
-          *yycharp = YYFAULTYTOK;
+          *yycharp = ]b4_symbol(1, id)[;
        }
 #endif // YY_EXCEPTIONS]], [[
      *yycharp = ]b4_lex[;]])[
@@ -1030,8 +1030,14 @@ static inline int
 yygetLRActions (yy_state_t yystate, yysymbol_kind_t yytoken, const short** yyconflicts)
 {
  int yyindex = yypact[yystate] + yytoken;
-  if (yyisDefaultedState (yystate)
-      || yyindex < 0 || YYLAST < yyindex || yycheck[yyindex] != yytoken)
+  if (yytoken == ]b4_symbol(1, kind)[)
+    {
+      // This is the error token.
+      *yyconflicts = yyconfl;
+      return 0;
+    }
+  else if (yyisDefaultedState (yystate)
+           || yyindex < 0 || YYLAST < yyindex || yycheck[yyindex] != yytoken)
    {
      *yyconflicts = yyconfl;
      return -yydefact[yystate];
@@ -1096,7 +1102,7 @@ yynewGLRStackItem (yyGLRStack* yystackp, yybool yyisState)
 *  alternative actions for YYSTATE.  Assumes that YYRHS comes from
 *  stack #YYK of *YYSTACKP. */
 static void
-yyaddDeferredAction (yyGLRStack* yystackp, ptrdiff_t yyk, yyGLRState* yystate,
+yyaddDeferredAction (yyGLRStack* yystackp, YYPTRDIFF_T yyk, yyGLRState* yystate,
                     yyGLRState* yyrhs, yyRuleNum yyrule)
 {
  yySemanticOption* yynewOption =
@@ -1128,14 +1134,14 @@ yyinitStateSet (yyGLRStateSet* yyset)
  yyset->yycapacity = 16;
  yyset->yystates
    = YY_CAST (yyGLRState**,
-               YYMALLOC (YY_CAST (size_t, yyset->yycapacity)
+               YYMALLOC (YY_CAST (YYSIZE_T, yyset->yycapacity)
                         * sizeof yyset->yystates[0]));
  if (! yyset->yystates)
    return yyfalse;
  yyset->yystates[0] = YY_NULLPTR;
  yyset->yylookaheadNeeds
    = YY_CAST (yybool*,
-               YYMALLOC (YY_CAST (size_t, yyset->yycapacity)
+               YYMALLOC (YY_CAST (YYSIZE_T, yyset->yycapacity)
                         * sizeof yyset->yylookaheadNeeds[0]));
  if (! yyset->yylookaheadNeeds)
    {
@@ -1144,7 +1150,7 @@ yyinitStateSet (yyGLRStateSet* yyset)
    }
  memset (yyset->yylookaheadNeeds,
          0,
-          YY_CAST (size_t, yyset->yycapacity) * sizeof yyset->yylookaheadNeeds[0]);
+          YY_CAST (YYSIZE_T, yyset->yycapacity) * sizeof yyset->yylookaheadNeeds[0]);
  return yytrue;
 }

@@ -1157,14 +1163,14 @@ static void yyfreeStateSet (yyGLRStateSet* yyset)
 /** Initialize *YYSTACKP to a single empty stack, with total maximum
 *  capacity for all stacks of YYSIZE.  */
 static yybool
-yyinitGLRStack (yyGLRStack* yystackp, ptrdiff_t yysize)
+yyinitGLRStack (yyGLRStack* yystackp, YYPTRDIFF_T yysize)
 {
  yystackp->yyerrState = 0;
  yynerrs = 0;
  yystackp->yyspaceLeft = yysize;
  yystackp->yyitems
    = YY_CAST (yyGLRStackItem*,
-               YYMALLOC (YY_CAST (size_t, yysize)
+               YYMALLOC (YY_CAST (YYSIZE_T, yysize)
                         * sizeof yystackp->yynextFree[0]));
  if (!yystackp->yyitems)
    return yyfalse;
@@ -1190,9 +1196,9 @@ yyexpandGLRStack (yyGLRStack* yystackp)
 {
  yyGLRStackItem* yynewItems;
  yyGLRStackItem* yyp0, *yyp1;
-  ptrdiff_t yynewSize;
-  ptrdiff_t yyn;
-  ptrdiff_t yysize = yystackp->yynextFree - yystackp->yyitems;
+  YYPTRDIFF_T yynewSize;
+  YYPTRDIFF_T yyn;
+  YYPTRDIFF_T yysize = yystackp->yynextFree - yystackp->yyitems;
  if (YYMAXDEPTH - YYHEADROOM < yysize)
    yyMemoryExhausted (yystackp);
  yynewSize = 2*yysize;
@@ -1200,7 +1206,7 @@ yyexpandGLRStack (yyGLRStack* yystackp)
    yynewSize = YYMAXDEPTH;
  yynewItems
    = YY_CAST (yyGLRStackItem*,
-               YYMALLOC (YY_CAST (size_t, yynewSize)
+               YYMALLOC (YY_CAST (YYSIZE_T, yynewSize)
                         * sizeof yynewItems[0]));
  if (! yynewItems)
    yyMemoryExhausted (yystackp);
@@ -1265,7 +1271,7 @@ yyupdateSplit (yyGLRStack* yystackp, yyGLRState* yys)

 /** Invalidate stack #YYK in *YYSTACKP.  */
 static inline void
-yymarkStackDeleted (yyGLRStack* yystackp, ptrdiff_t yyk)
+yymarkStackDeleted (yyGLRStack* yystackp, YYPTRDIFF_T yyk)
 {
  if (yystackp->yytops.yystates[yyk] != YY_NULLPTR)
    yystackp->yylastDeleted = yystackp->yytops.yystates[yyk];
@@ -1289,7 +1295,7 @@ yyundeleteLastStack (yyGLRStack* yystackp)
 static inline void
 yyremoveDeletes (yyGLRStack* yystackp)
 {
-  ptrdiff_t yyi, yyj;
+  YYPTRDIFF_T yyi, yyj;
  yyi = yyj = 0;
  while (yyj < yystackp->yytops.yysize)
    {
@@ -1322,8 +1328,8 @@ yyremoveDeletes (yyGLRStack* yystackp)
 * state YYLRSTATE, at input position YYPOSN, with (resolved) semantic
 * value *YYVALP and source location *YYLOCP.  */
 static inline void
-yyglrShift (yyGLRStack* yystackp, ptrdiff_t yyk, yy_state_t yylrState,
-            ptrdiff_t yyposn,
+yyglrShift (yyGLRStack* yystackp, YYPTRDIFF_T yyk, yy_state_t yylrState,
+            YYPTRDIFF_T yyposn,
            YYSTYPE* yyvalp]b4_locations_if([, YYLTYPE* yylocp])[)
 {
  yyGLRState* yynewState = &yynewGLRStackItem (yystackp, yytrue)->yystate;
@@ -1343,8 +1349,8 @@ yyglrShift (yyGLRStack* yystackp, ptrdiff_t yyk, yy_state_t yylrState,
 *  state YYLRSTATE, at input position YYPOSN, with the (unresolved)
 *  semantic value of YYRHS under the action for YYRULE.  */
 static inline void
-yyglrShiftDefer (yyGLRStack* yystackp, ptrdiff_t yyk, yy_state_t yylrState,
-                 ptrdiff_t yyposn, yyGLRState* yyrhs, yyRuleNum yyrule)
+yyglrShiftDefer (yyGLRStack* yystackp, YYPTRDIFF_T yyk, yy_state_t yylrState,
+                 YYPTRDIFF_T yyposn, yyGLRState* yyrhs, yyRuleNum yyrule)
 {
  yyGLRState* yynewState = &yynewGLRStackItem (yystackp, yytrue)->yystate;
  YY_ASSERT (yynewState->yyisState);
@@ -1374,7 +1380,7 @@ yyglrShiftDefer (yyGLRStack* yystackp, ptrdiff_t yyk, yy_state_t yylrState,
 `----------------------------------------------------------------------*/

 static inline void
-yy_reduce_print (yybool yynormal, yyGLRStackItem* yyvsp, ptrdiff_t yyk,
+yy_reduce_print (yybool yynormal, yyGLRStackItem* yyvsp, YYPTRDIFF_T yyk,
                 yyRuleNum yyrule]b4_user_formals[)
 {
  int yynrhs = yyrhsLength (yyrule);]b4_locations_if([
@@ -1407,7 +1413,7 @@ yy_reduce_print (yybool yynormal, yyGLRStackItem* yyvsp, ptrdiff_t yyk,
 *  and *YYLOCP to the computed location (if any).  Return value is as
 *  for userAction.  */
 static inline YYRESULTTAG
-yydoAction (yyGLRStack* yystackp, ptrdiff_t yyk, yyRuleNum yyrule,
+yydoAction (yyGLRStack* yystackp, YYPTRDIFF_T yyk, yyRuleNum yyrule,
            YYSTYPE* yyvalp]b4_locuser_formals[)
 {
  int yynrhs = yyrhsLength (yyrule);
@@ -1459,10 +1465,10 @@ yydoAction (yyGLRStack* yystackp, ptrdiff_t yyk, yyRuleNum yyrule,
 *  added to the options for the existing state's semantic value.
 */
 static inline YYRESULTTAG
-yyglrReduce (yyGLRStack* yystackp, ptrdiff_t yyk, yyRuleNum yyrule,
+yyglrReduce (yyGLRStack* yystackp, YYPTRDIFF_T yyk, yyRuleNum yyrule,
             yybool yyforceEval]b4_user_formals[)
 {
-  ptrdiff_t yyposn = yystackp->yytops.yystates[yyk]->yyposn;
+  YYPTRDIFF_T yyposn = yystackp->yytops.yystates[yyk]->yyposn;

  if (yyforceEval || yystackp->yysplitPoint == YY_NULLPTR)
    {
@@ -1484,7 +1490,7 @@ yyglrReduce (yyGLRStack* yystackp, ptrdiff_t yyk, yyRuleNum yyrule,
    }
  else
    {
-      ptrdiff_t yyi;
+      YYPTRDIFF_T yyi;
      int yyn;
      yyGLRState* yys, *yys0 = yystackp->yytops.yystates[yyk];
      yy_state_t yynewLRState;
@@ -1526,8 +1532,8 @@ yyglrReduce (yyGLRStack* yystackp, ptrdiff_t yyk, yyRuleNum yyrule,
  return yyok;
 }

-static ptrdiff_t
-yysplitStack (yyGLRStack* yystackp, ptrdiff_t yyk)
+static YYPTRDIFF_T
+yysplitStack (yyGLRStack* yystackp, YYPTRDIFF_T yyk)
 {
  if (yystackp->yysplitPoint == YY_NULLPTR)
    {
@@ -1536,8 +1542,8 @@ yysplitStack (yyGLRStack* yystackp, ptrdiff_t yyk)
    }
  if (yystackp->yytops.yycapacity <= yystackp->yytops.yysize)
    {
-      ptrdiff_t state_size = sizeof yystackp->yytops.yystates[0];
-      ptrdiff_t half_max_capacity = YYSIZEMAX / 2 / state_size;
+      YYPTRDIFF_T state_size = YYSIZEOF (yystackp->yytops.yystates[0]);
+      YYPTRDIFF_T half_max_capacity = YYSIZE_MAXIMUM / 2 / state_size;
      if (half_max_capacity < yystackp->yytops.yycapacity)
        yyMemoryExhausted (yystackp);
      yystackp->yytops.yycapacity *= 2;
@@ -1546,7 +1552,7 @@ yysplitStack (yyGLRStack* yystackp, ptrdiff_t yyk)
        yyGLRState** yynewStates
          = YY_CAST (yyGLRState**,
                     YYREALLOC (yystackp->yytops.yystates,
-                                (YY_CAST (size_t, yystackp->yytops.yycapacity)
+                                (YY_CAST (YYSIZE_T, yystackp->yytops.yycapacity)
                                 * sizeof yynewStates[0])));
        if (yynewStates == YY_NULLPTR)
          yyMemoryExhausted (yystackp);
@@ -1557,7 +1563,7 @@ yysplitStack (yyGLRStack* yystackp, ptrdiff_t yyk)
        yybool* yynewLookaheadNeeds
          = YY_CAST (yybool*,
                     YYREALLOC (yystackp->yytops.yylookaheadNeeds,
-                                (YY_CAST (size_t, yystackp->yytops.yycapacity)
+                                (YY_CAST (YYSIZE_T, yystackp->yytops.yycapacity)
                                 * sizeof yynewLookaheadNeeds[0])));
        if (yynewLookaheadNeeds == YY_NULLPTR)
          yyMemoryExhausted (yystackp);
@@ -1988,8 +1994,8 @@ yycompressStack (yyGLRStack* yystackp)
 }

 static YYRESULTTAG
-yyprocessOneStack (yyGLRStack* yystackp, ptrdiff_t yyk,
-                   ptrdiff_t yyposn]b4_pure_formals[)
+yyprocessOneStack (yyGLRStack* yystackp, YYPTRDIFF_T yyk,
+                   YYPTRDIFF_T yyposn]b4_pure_formals[)
 {
  while (yystackp->yytops.yystates[yyk] != YY_NULLPTR)
    {
@@ -2029,10 +2035,10 @@ yyprocessOneStack (yyGLRStack* yystackp, ptrdiff_t yyk,
          const int yyaction = yygetLRActions (yystate, yytoken, &yyconflicts);
          yystackp->yytops.yylookaheadNeeds[yyk] = yytrue;

-          while (*yyconflicts != 0)
+          for (/* nothing */; *yyconflicts; yyconflicts += 1)
            {
              YYRESULTTAG yyflag;
-              ptrdiff_t yynewStack = yysplitStack (yystackp, yyk);
+              YYPTRDIFF_T yynewStack = yysplitStack (yystackp, yyk);
              YY_DPRINTF ((stderr, "Splitting off stack %ld from %ld.\n",
                           YY_CAST (long, yynewStack), YY_CAST (long, yyk)));
              yyflag = yyglrReduce (yystackp, yynewStack,
@@ -2048,7 +2054,6 @@ yyprocessOneStack (yyGLRStack* yystackp, ptrdiff_t yyk,
                }
              else
                return yyflag;
-              yyconflicts += 1;
            }

          if (yyisShiftAction (yyaction))
@@ -2103,7 +2108,7 @@ yypcontext_expected_tokens (const yyGLRStack* yystackp,
      int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
      int yyx;
      for (yyx = yyxbegin; yyx < yyxend; ++yyx)
-        if (yycheck[yyx + yyn] == yyx && yyx != ]b4_symbol_prefix[YYERROR
+        if (yycheck[yyx + yyn] == yyx && yyx != ]b4_symbol(1, kind)[
            && !yytable_value_is_error (yytable[yyx + yyn]))
          {
            if (!yyarg)
@@ -2114,6 +2119,8 @@ yypcontext_expected_tokens (const yyGLRStack* yystackp,
              yyarg[yycount++] = YY_CAST (yysymbol_kind_t, yyx);
          }
    }
+  if (yyarg && yycount == 0 && 0 < yyargn)
+    yyarg[0] = ]b4_symbol(-2, kind)[;
  return yycount;
 }]])[

@@ -2221,7 +2228,7 @@ yyreportSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
     one per "expected"). */
  yysymbol_kind_t yyarg[YYARGS_MAX];
  /* Cumulated lengths of YYARG.  */
-  ptrdiff_t yysize = 0;
+  YYPTRDIFF_T yysize = 0;

  /* Actual size of YYARG. */
  int yycount
@@ -2252,11 +2259,11 @@ yyreportSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
    int yyi;
    for (yyi = 0; yyi < yycount; ++yyi)
      {
-        ptrdiff_t yysz
+        YYPTRDIFF_T yysz
          = ]b4_parse_error_case(
                     [verbose], [[yytnamerr (YY_NULLPTR, yytname[yyarg[yyi]])]],
                     [[yystrlen (yysymbol_name (yyarg[yyi]))]]);[
-        if (YYSIZEMAX - yysize < yysz)
+        if (YYSIZE_MAXIMUM - yysize < yysz)
          yysize_overflow = yytrue;
        else
          yysize += yysz;
@@ -2264,7 +2271,7 @@ yyreportSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
  }

  if (!yysize_overflow)
-    yymsg = YY_CAST (char *, YYMALLOC (YY_CAST (size_t, yysize)));
+    yymsg = YY_CAST (char *, YYMALLOC (YY_CAST (YYSIZE_T, yysize)));

  if (yymsg)
    {
@@ -2341,7 +2348,7 @@ yyrecoverSyntaxError (yyGLRStack* yystackp]b4_user_formals[)

  /* Reduce to one stack.  */
  {
-    ptrdiff_t yyk;
+    YYPTRDIFF_T yyk;
    for (yyk = 0; yyk < yystackp->yytops.yysize; yyk += 1)
      if (yystackp->yytops.yystates[yyk] != YY_NULLPTR)
        break;
@@ -2361,8 +2368,8 @@ yyrecoverSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
      int yyj = yypact[yys->yylrState];
      if (! yypact_value_is_default (yyj))
        {
-          yyj += ]b4_symbol_prefix[YYERROR;
-          if (0 <= yyj && yyj <= YYLAST && yycheck[yyj] == ]b4_symbol_prefix[YYERROR
+          yyj += ]b4_symbol(1, kind)[;
+          if (0 <= yyj && yyj <= YYLAST && yycheck[yyj] == ]b4_symbol(1, kind)[
              && yyisShiftAction (yytable[yyj]))
            {
              /* Shift the error token.  */
@@ -2416,7 +2423,7 @@ yyparse (]m4_ifset([b4_parse_param], [b4_formals(b4_parse_param)], [void])[)
  int yyresult;
  yyGLRStack yystack;
  yyGLRStack* const yystackp = &yystack;
-  ptrdiff_t yyposn;
+  YYPTRDIFF_T yyposn;

  YY_DPRINTF ((stderr, "Starting parse\n"));

@@ -2445,7 +2452,7 @@ b4_dollar_popdef])[]dnl
      /* For efficiency, we have two loops, the first of which is
         specialized to deterministic operation (single stack, no
         potential ambiguity).  */
-      /* Standard mode */
+      /* Standard mode. */
      while (yytrue)
        {
          yy_state_t yystate = yystack.yytops.yystates[0]->yylrState;
@@ -2468,7 +2475,8 @@ b4_dollar_popdef])[]dnl
              yysymbol_kind_t yytoken = ]b4_yygetToken_call;[
              const short* yyconflicts;
              int yyaction = yygetLRActions (yystate, yytoken, &yyconflicts);
-              if (*yyconflicts != 0)
+              if (*yyconflicts)
+                /* Enter nondeterministic mode.  */
                break;
              if (yyisShiftAction (yyaction))
                {
@@ -2481,11 +2489,11 @@ b4_dollar_popdef])[]dnl
                }
              else if (yyisErrorAction (yyaction))
                {]b4_locations_if([[
-                  yystack.yyerror_range[1].yystate.yyloc = yylloc;]])[]b4_glr_cc_if([[
-                  /* Don't issue an error message again for exceptions
-                     thrown from the scanner.  */
-                  if (yychar != YYFAULTYTOK)
-  ]])[                  yyreportSyntaxError (&yystack]b4_user_args[);
+                  yystack.yyerror_range[1].yystate.yyloc = yylloc;]])[
+                  /* Issue an error message unless the scanner already
+                     did. */
+                  if (yychar != ]b4_symbol(1, id)[)
+                    yyreportSyntaxError (&yystack]b4_user_args[);
                  goto yyuser_error;
                }
              else
@@ -2493,10 +2501,11 @@ b4_dollar_popdef])[]dnl
            }
        }

+      /* Nondeterministic mode. */
      while (yytrue)
        {
          yysymbol_kind_t yytoken_to_shift;
-          ptrdiff_t yys;
+          YYPTRDIFF_T yys;

          for (yys = 0; yys < yystack.yytops.yysize; yys += 1)
            yystackp->yytops.yylookaheadNeeds[yys] = yychar != ]b4_symbol(-2, id)[;
@@ -2603,8 +2612,8 @@ b4_dollar_popdef])[]dnl
      yyGLRState** yystates = yystack.yytops.yystates;
      if (yystates)
        {
-          ptrdiff_t yysize = yystack.yytops.yysize;
-          ptrdiff_t yyk;
+          YYPTRDIFF_T yysize = yystack.yytops.yysize;
+          YYPTRDIFF_T yyk;
          for (yyk = 0; yyk < yysize; yyk += 1)
            if (yystates[yyk])
              {
@@ -2651,7 +2660,7 @@ yypstates (yyGLRState* yyst)
 }

 static void
-yypstack (yyGLRStack* yystackp, ptrdiff_t yyk)
+yypstack (yyGLRStack* yystackp, YYPTRDIFF_T yyk)
 {
  yypstates (yystackp->yytops.yystates[yyk]);
 }
@@ -2696,7 +2705,7 @@ yypdumpstack (yyGLRStack* yystackp)

  YY_FPRINTF ((stderr, "Tops:"));
  {
-    ptrdiff_t yyi;
+    YYPTRDIFF_T yyi;
    for (yyi = 0; yyi < yystackp->yytops.yysize; yyi += 1)
      YY_FPRINTF ((stderr, "%ld: %ld; ", YY_CAST (long, yyi),
                   YYINDEX (yystackp->yytops.yystates[yyi])));
@@ -167,7 +167,7 @@ m4_pushdef([b4_parse_param], m4_defn([b4_parse_param_orig]))dnl
  void
  ]b4_parser_class[::yy_symbol_value_print_ (symbol_kind_type yykind,
                           const semantic_type* yyvaluep]b4_locations_if([[,
-                           const location_type* yylocationp]])[)
+                           const location_type* yylocationp]])[) const
  {]b4_locations_if([[
    YYUSE (yylocationp);]])[
    YYUSE (yyvaluep);
@@ -181,7 +181,7 @@ m4_pushdef([b4_parse_param], m4_defn([b4_parse_param_orig]))dnl
  void
  ]b4_parser_class[::yy_symbol_print_ (symbol_kind_type yykind,
                           const semantic_type* yyvaluep]b4_locations_if([[,
-                           const location_type* yylocationp]])[)
+                           const location_type* yylocationp]])[) const
  {
    *yycdebug_ << (yykind < YYNTOKENS ? "token" : "nterm")
               << ' ' << yytname[yykind] << " ("]b4_locations_if([[
@@ -317,16 +317,16 @@ b4_percent_code_get([[requires]])[
    /// \param yylocationp  Its location.]])[
    virtual void yy_symbol_value_print_ (symbol_kind_type yykind,
                                         const semantic_type* yyvaluep]b4_locations_if([[,
-                                         const location_type* yylocationp]])[);
+                                         const location_type* yylocationp]])[) const;
    /// \brief Report a symbol on the debug stream.
    /// \param yykind       The symbol kind.
    /// \param yyvaluep     Its semantic value.]b4_locations_if([[
    /// \param yylocationp  Its location.]])[
    virtual void yy_symbol_print_ (symbol_kind_type yykind,
                                   const semantic_type* yyvaluep]b4_locations_if([[,
-                                   const location_type* yylocationp]])[);
+                                   const location_type* yylocationp]])[) const;
  private:
-    // Debugging.
+    /// Debug stream.
    std::ostream* yycdebug_;
 #endif

@@ -344,6 +344,8 @@ b4_percent_define_flag_if([[global_tokens_and_yystype]],
 #define ]b4_symbol(-2, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(-2, [id])[
 #undef ]b4_symbol(0, [id])[
 #define ]b4_symbol(0, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(0, [id])[
+#undef ]b4_symbol(1, [id])[
+#define ]b4_symbol(1, [id])[ ]b4_namespace_ref[::]b4_parser_class[::token::]b4_symbol(1, [id])[

 #ifndef ]b4_api_PREFIX[STYPE
 # define ]b4_api_PREFIX[STYPE ]b4_namespace_ref[::]b4_parser_class[::semantic_type
@@ -354,10 +356,10 @@ b4_percent_define_flag_if([[global_tokens_and_yystype]],

 ]m4_define([b4_declare_symbol_enum],
 [[typedef ]b4_namespace_ref[::]b4_parser_class[::symbol_kind_type yysymbol_kind_t;
-#define ]b4_symbol_prefix[YYEMPTY ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEMPTY
-#define ]b4_symbol_prefix[YYERROR ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYERROR
-#define ]b4_symbol_prefix[YYEOF   ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEOF
-#define ]b4_symbol_prefix[YYUNDEF ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYUNDEF
+#define ]b4_symbol_prefix[YYEMPTY  ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEMPTY
+#define ]b4_symbol_prefix[YYerror  ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYerror
+#define ]b4_symbol_prefix[YYEOF    ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYEOF
+#define ]b4_symbol_prefix[YYUNDEF  ]b4_namespace_ref[::]b4_parser_class[::symbol_kind::]b4_symbol_prefix[YYUNDEF
 ]])[
 ]b4_percent_code_get([[provides]])[
 ]m4_popdef([b4_parse_param])dnl
@@ -137,9 +137,14 @@ m4_define([b4_integral_parser_table_define],
 # ------------------------
 # Output the definition of this token as an enum.
 m4_define([b4_token_enum],
-[b4_token_format([    /** Token number, to be returned by the scanner.  */
-    static final int %s = %s;
-], [$1])])
+[b4_token_visible_if([$1],
+    [m4_format([[    /** Token %s, to be returned by the scanner.  */
+    static final int %s = %s%s;
+]],
+               b4_symbol([$1], [tag]),
+               b4_symbol([$1], [id]),
+               b4_symbol([$1], b4_api_token_raw_if([[number]], [[user_number]])))])])
+

 # b4_token_enums
 # --------------
@@ -344,7 +349,7 @@ m4_define([b4_symbol_translate],
 # ----------------
 # Translate a string if i18n is enabled.  Avoid collision with b4_translate.
 m4_define([b4_trans],
-[m4_if(b4_has_translations, 0, [$1], [i18n($1)])])
+[b4_has_translations_if([i18n($1)], [$1])])



@@ -204,6 +204,13 @@ m4_define([b4_shared_declarations],
    ]b4_parser_class[ (]b4_parse_param_decl[);
    virtual ~]b4_parser_class[ ();

+#if 201103L <= YY_CPLUSPLUS
+    /// Non copyable.
+    ]b4_parser_class[ (const ]b4_parser_class[&) = delete;
+    /// Non copyable.
+    ]b4_parser_class[& operator= (const ]b4_parser_class[&) = delete;
+#endif
+
    /// Parse.  An alias for parse ().
    /// \returns  0 iff parsing succeeded.
    int operator() ();
@@ -234,6 +241,23 @@ m4_define([b4_shared_declarations],
    /// Report a syntax error.
    void error (const syntax_error& err);

+]b4_parse_error_bmatch(
+[custom\|detailed],
+[[    /// The user-facing name of the symbol whose (internal) number is
+    /// YYSYMBOL.  No bounds checking.
+    static const char *symbol_name (symbol_kind_type yysymbol);]],
+[simple],
+[[#if ]b4_api_PREFIX[DEBUG || ]b4_token_table_flag[
+    /// The user-facing name of the symbol whose (internal) number is
+    /// YYSYMBOL.  No bounds checking.
+    static const char *symbol_name (symbol_kind_type yysymbol);
+#endif // #if ]b4_api_PREFIX[DEBUG || ]b4_token_table_flag[
+]],
+[verbose],
+[[    /// The user-facing name of the symbol whose (internal) number is
+    /// YYSYMBOL.  No bounds checking.
+    static std::string symbol_name (symbol_kind_type yysymbol);]])[
+
 ]b4_token_constructor_define[
 ]b4_parse_error_bmatch([custom\|detailed\|verbose], [[
    class context
@@ -255,10 +279,13 @@ m4_define([b4_shared_declarations],
    };
 ]])[
  private:
-    /// This class is not copyable.
+#if YY_CPLUSPLUS < 201103L
+    /// Non copyable.
    ]b4_parser_class[ (const ]b4_parser_class[&);
-    ]b4_parser_class[& operator= (const ]b4_parser_class[&);]b4_lac_if([[
-
+    /// Non copyable.
+    ]b4_parser_class[& operator= (const ]b4_parser_class[&);
+#endif
+]b4_lac_if([[
    /// Check the lookahead yytoken.
    /// \returns  true iff the token will be eventually shifted.
    bool yy_lac_check_ (symbol_kind_type yytoken) const;
@@ -305,35 +332,32 @@ m4_define([b4_shared_declarations],
    /// In theory \a t should be a token_kind_type, but character literals
    /// are valid, yet not members of the token_type enum.
    static symbol_kind_type yytranslate_ (int t);
-]b4_parse_error_bmatch([custom\|detailed], [[
-   /// The user-facing name of the symbol whose (internal) number is
-   /// YYSYMBOL.  No bounds checking.
-   static const char *symbol_name (symbol_kind_type yysymbol);
+
+]b4_parse_error_bmatch(
+[simple],
+[[#if ]b4_api_PREFIX[DEBUG || ]b4_token_table_flag[
+    /// For a symbol, its name in clear.
+    static const char* const yytname_[];
+#endif // #if ]b4_api_PREFIX[DEBUG || ]b4_token_table_flag[
+]],
+[verbose],
+[[    /// Convert the symbol name \a n to a form suitable for a diagnostic.
+    static std::string yytnamerr_ (const char *yystr);
+
+    /// For a symbol, its name in clear.
+    static const char* const yytname_[];
 ]])[

    // Tables.
 ]b4_parser_tables_declare[
-]b4_parse_error_case([verbose], [[
-    /// Convert the symbol name \a n to a form suitable for a diagnostic.
-    static std::string yytnamerr_ (const char *n);
-
-    /// For a symbol, its name in clear.
-    static const char* const yytname_[];
-]],
-[b4_token_table_if([], [[
-#if ]b4_api_PREFIX[DEBUG
-    /// For a symbol, its name in clear.
-    static const char* const yytname_[];
-#endif
-]])])[

 #if ]b4_api_PREFIX[DEBUG
 ]b4_integral_parser_table_declare([rline], [b4_rline],
     [[YYRLINE[YYN] -- Source line where rule number YYN was defined.]])[
    /// Report on the debug stream that the rule \a r is going to be reduced.
-    virtual void yy_reduce_print_ (int r);
+    virtual void yy_reduce_print_ (int r) const;
    /// Print the state stack on the debug stream.
-    virtual void yystack_print_ ();
+    virtual void yy_stack_print_ () const;

    /// Debugging level.
    int yydebug_;
@@ -455,6 +479,7 @@ m4_define([b4_shared_declarations],
    };

 ]b4_parse_param_vars[
+]b4_percent_code_get([[yy_bison_internal_hook]])[
  };

 ]b4_token_ctor_if([b4_yytranslate_define([$1])[
@@ -523,6 +548,11 @@ m4_if(b4_prefix, [yy], [],
 #  define YY_(msgid) msgid
 # endif
 #endif
+]b4_has_translations_if([
+#ifndef N_
+# define N_(Msgid) Msgid
+#endif
+])[

 // Whether we are compiled with exception support.
 #ifndef YY_EXCEPTIONS
@@ -562,7 +592,7 @@ m4_if(b4_prefix, [yy], [],
 # define YY_STACK_PRINT()               \
  do {                                  \
    if (yydebug_)                       \
-      yystack_print_ ();                \
+      yy_stack_print_ ();                \
  } while (false)

 #else // !]b4_api_PREFIX[DEBUG
@@ -582,71 +612,7 @@ m4_if(b4_prefix, [yy], [],
 #define YYERROR         goto yyerrorlab
 #define YYRECOVERING()  (!!yyerrstatus_)

-]b4_namespace_open[]b4_parse_error_bmatch([custom\|detailed], [[
-  /* The user-facing name of the symbol whose (internal) number is
-     YYSYMBOL.  No bounds checking. */
-  const char *
-  ]b4_parser_class[::symbol_name (symbol_kind_type yysymbol)
-  {
-    static const char *const yy_sname[] =
-    {
-    ]b4_symbol_names[
-    };]m4_ifdef([b4_translatable], [[
-    /* YYTRANSLATABLE[SYMBOL-NUM] -- Whether YYTNAME[SYMBOL-NUM] is
-       internationalizable.  */
-    static ]b4_int_type_for([b4_translatable])[ yytranslatable[] =
-    {
-    ]b4_translatable[
-    };
-    return (yysymbol < YYNTOKENS && yytranslatable[yysymbol]
-            ? _(yy_sname[yysymbol])
-            : yy_sname[yysymbol]);]], [[
-    return yy_sname[yysymbol];]])[
-  }
-]])
-b4_parse_error_case([verbose], [[
-
-  /* Return YYSTR after stripping away unnecessary quotes and
-     backslashes, so that it's suitable for yyerror.  The heuristic is
-     that double-quoting is unnecessary unless the string contains an
-     apostrophe, a comma, or backslash (other than backslash-backslash).
-     YYSTR is taken from yytname.  */
-  std::string
-  ]b4_parser_class[::yytnamerr_ (const char *yystr)
-  {
-    if (*yystr == '"')
-      {
-        std::string yyr;
-        char const *yyp = yystr;
-
-        for (;;)
-          switch (*++yyp)
-            {
-            case '\'':
-            case ',':
-              goto do_not_strip_quotes;
-
-            case '\\':
-              if (*++yyp != '\\')
-                goto do_not_strip_quotes;
-              else
-                goto append;
-
-            append:
-            default:
-              yyr += *yyp;
-              break;
-
-            case '"':
-              return yyr;
-            }
-      do_not_strip_quotes: ;
-      }
-
-    return yystr;
-  }
-]])[
-
+]b4_namespace_open[
  /// Build a parser object.
  ]b4_parser_class::b4_parser_class[ (]b4_parse_param_decl[)
 #if ]b4_api_PREFIX[DEBUG
@@ -725,7 +691,7 @@ b4_parse_error_case([verbose], [[
    b4_symbol_variant([that.kind ()],
                      [value], [move], [YY_MOVE (that.value)])])[
    // that is emptied.
-    that.type = symbol_kind::]b4_symbol(-2, kind)[;
+    that.kind_ = symbol_kind::]b4_symbol(-2, kind)[;
  }

 #if YY_CPLUSPLUS < 201103L
@@ -768,23 +734,21 @@ b4_parse_error_case([verbose], [[
 #if ]b4_api_PREFIX[DEBUG
  template <typename Base>
  void
-  ]b4_parser_class[::yy_print_ (std::ostream& yyo,
-                                     const basic_symbol<Base>& yysym) const
+  ]b4_parser_class[::yy_print_ (std::ostream& yyo, const basic_symbol<Base>& yysym) const
  {
    std::ostream& yyoutput = yyo;
    YYUSE (yyoutput);
-    symbol_kind_type yykind = yysym.kind ();
-#if defined __GNUC__ && ! defined __clang__ && ! defined __ICC && __GNUC__ * 100 + __GNUC_MINOR__ <= 408
-    // Avoid a (spurious) G++ 4.8 warning about "array subscript is
-    // below array bounds".
    if (yysym.empty ())
-      std::abort ();
-#endif
-    yyo << (yykind < YYNTOKENS ? "token" : "nterm")
-        << ' ' << yytname_[yykind] << " ("]b4_locations_if([
-        << yysym.location << ": "])[;
-    ]b4_symbol_actions([printer])[
-    yyo << ')';
+      yyo << "empty symbol";
+    else
+      {
+        symbol_kind_type yykind = yysym.kind ();
+        yyo << (yykind < YYNTOKENS ? "token" : "nterm")
+            << ' ' << yysym.name () << " ("]b4_locations_if([
+            << yysym.location << ": "])[;
+        ]b4_symbol_actions([printer])[
+        yyo << ')';
+      }
  }
 #endif

@@ -943,7 +907,7 @@ b4_dollar_popdef])[]dnl
          {]b4_token_ctor_if([[
            symbol_type yylookahead (]b4_lex[);
            yyla.move (yylookahead);]], [[
-            yyla.type = yytranslate_ (]b4_lex[);]])[
+            yyla.kind_ = yytranslate_ (]b4_lex[);]])[
          }
 #if YY_EXCEPTIONS
        catch (const syntax_error& yyexc)
@@ -956,6 +920,16 @@ b4_dollar_popdef])[]dnl
      }
    YY_SYMBOL_PRINT ("Next token is", yyla);

+    if (yyla.kind () == ]symbol_kind::b4_symbol(1, kind)[)
+    {
+      // The scanner already issued an error message, process directly
+      // to error recovery.  But do not keep the error token as
+      // lookahead, it is too special and may lead us to an endless
+      // loop in error recovery. */
+      yyla.kind_ = ]symbol_kind::b4_symbol(2, kind)[;
+      goto yyerrlab1;
+    }
+
    /* If the proper action on seeing token YYLA.TYPE is to reduce or
       to detect an error, take that action.  */
    yyn += yyla.kind ();
@@ -1130,9 +1104,9 @@ b4_dollar_popdef])[]dnl
        yyn = yypact_[+yystack_[0].state];
        if (!yy_pact_value_is_default_ (yyn))
          {
-            yyn += symbol_kind::]b4_symbol_prefix[YYERROR;
+            yyn += symbol_kind::]b4_symbol(1, kind)[;
            if (0 <= yyn && yyn <= yylast_
-                && yycheck_[yyn] == symbol_kind::]b4_symbol_prefix[YYERROR)
+                && yycheck_[yyn] == symbol_kind::]b4_symbol(1, kind)[)
              {
                yyn = yytable_[yyn];
                if (0 < yyn)
@@ -1222,8 +1196,86 @@ b4_dollar_popdef])[]dnl
  {
    error (]b4_join(b4_locations_if([yyexc.location]),
                    [[yyexc.what ()]])[);
-  }]b4_parse_error_bmatch([custom\|detailed\|verbose], [[
+  }

+]b4_parse_error_bmatch([custom\|detailed],
+[[  const char *
+  ]b4_parser_class[::symbol_name (symbol_kind_type yysymbol)
+  {
+    static const char *const yy_sname[] =
+    {
+    ]b4_symbol_names[
+    };]b4_has_translations_if([[
+    /* YYTRANSLATABLE[SYMBOL-NUM] -- Whether YY_SNAME[SYMBOL-NUM] is
+       internationalizable.  */
+    static ]b4_int_type_for([b4_translatable])[ yytranslatable[] =
+    {
+    ]b4_translatable[
+    };
+    return (yysymbol < YYNTOKENS && yytranslatable[yysymbol]
+            ? _(yy_sname[yysymbol])
+            : yy_sname[yysymbol]);]], [[
+    return yy_sname[yysymbol];]])[
+  }
+]],
+[simple],
+[[#if ]b4_api_PREFIX[DEBUG || ]b4_token_table_flag[
+  const char *
+  ]b4_parser_class[::symbol_name (symbol_kind_type yysymbol)
+  {
+    return yytname_[yysymbol];
+  }
+#endif // #if ]b4_api_PREFIX[DEBUG || ]b4_token_table_flag[
+]],
+[verbose],
+[[  /* Return YYSTR after stripping away unnecessary quotes and
+     backslashes, so that it's suitable for yyerror.  The heuristic is
+     that double-quoting is unnecessary unless the string contains an
+     apostrophe, a comma, or backslash (other than backslash-backslash).
+     YYSTR is taken from yytname.  */
+  std::string
+  ]b4_parser_class[::yytnamerr_ (const char *yystr)
+  {
+    if (*yystr == '"')
+      {
+        std::string yyr;
+        char const *yyp = yystr;
+
+        for (;;)
+          switch (*++yyp)
+            {
+            case '\'':
+            case ',':
+              goto do_not_strip_quotes;
+
+            case '\\':
+              if (*++yyp != '\\')
+                goto do_not_strip_quotes;
+              else
+                goto append;
+
+            append:
+            default:
+              yyr += *yyp;
+              break;
+
+            case '"':
+              return yyr;
+            }
+      do_not_strip_quotes: ;
+      }
+
+    return yystr;
+  }
+
+  std::string
+  ]b4_parser_class[::symbol_name (symbol_kind_type yysymbol)
+  {
+    return yytnamerr_ (yytname_[yysymbol]);
+  }
+]])[
+
+]b4_parse_error_bmatch([custom\|detailed\|verbose], [[
  // ]b4_parser_class[::context.
  ]b4_parser_class[::context::context (const ]b4_parser_class[& yyparser, const symbol_type& yyla)
    : yyparser_ (yyparser)
@@ -1246,7 +1298,7 @@ b4_dollar_popdef])[]dnl
    for (int yyx = 0; yyx < YYNTOKENS; ++yyx)
      {
        symbol_kind_type yysym = YY_CAST (symbol_kind_type, yyx);
-        if (yysym != symbol_kind::]b4_symbol_prefix[YYERROR
+        if (yysym != symbol_kind::]b4_symbol(1, kind)[
            && yysym != symbol_kind::]b4_symbol_prefix[YYUNDEF
            && yyparser_.yy_lac_check_ (yysym))
          {
@@ -1269,7 +1321,7 @@ b4_dollar_popdef])[]dnl
        int yychecklim = yylast_ - yyn + 1;
        int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
        for (int yyx = yyxbegin; yyx < yyxend; ++yyx)
-          if (yycheck_[yyx + yyn] == yyx && yyx != symbol_kind::]b4_symbol_prefix[YYERROR
+          if (yycheck_[yyx + yyn] == yyx && yyx != symbol_kind::]b4_symbol(1, kind)[
              && !yy_table_value_is_error_ (yytable_[yyx + yyn]))
            {
              if (!yyarg)
@@ -1281,6 +1333,8 @@ b4_dollar_popdef])[]dnl
            }
      }
 ]])[
+    if (yyarg && yycount == 0 && 0 < yyargn)
+      yyarg[0] = symbol_kind::]b4_symbol(-2, kind)[;
    return yycount;
  }

@@ -1293,7 +1347,7 @@ b4_dollar_popdef])[]dnl
    yylac_stack_.clear ();
    // Reduce until we encounter a shift and thereby accept the token.
 #if ]b4_api_PREFIX[DEBUG
-    YYCDEBUG << "LAC: checking lookahead " << yytname_[yytoken] << ':';
+    YYCDEBUG << "LAC: checking lookahead " << symbol_name (yytoken) << ':';
 #endif
    std::ptrdiff_t lac_top = 0;
    while (true)
@@ -1393,7 +1447,7 @@ b4_dollar_popdef])[]dnl
      {
 #if ]b4_api_PREFIX[DEBUG
        YYCDEBUG << "LAC: initial context established for "
-                 << yytname_[yytoken] << '\n';
+                 << symbol_name (yytoken) << '\n';
 #endif
        yy_lac_established_ = true;
        return yy_lac_check_ (yytoken);
@@ -1502,9 +1556,7 @@ b4_dollar_popdef])[]dnl
    for (char const* yyp = yyformat; *yyp; ++yyp)
      if (yyp[0] == '%' && yyp[1] == 's' && yyi < yycount)
        {
-          yyres += ]b4_parse_error_case([verbose],
-                [[yytnamerr_ (yytname_[yyarg[yyi++]])]],
-                [[symbol_name (yyarg[yyi++])]])[;
+          yyres += symbol_name (yyarg[yyi++]);
          ++yyp;
        }
      else
@@ -1519,7 +1571,8 @@ b4_dollar_popdef])[]dnl

 ]b4_parser_tables_define[

-]b4_tname_if([], [[#if ]b4_api_PREFIX[DEBUG]])[
+]b4_parse_error_bmatch([simple\|verbose],
+[[#if ]b4_api_PREFIX[DEBUG]b4_tname_if([[ || 1]])[
  // YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
  // First, the terminals, then, starting at \a YYNTOKENS, nonterminals.
  const char*
@@ -1527,13 +1580,14 @@ b4_dollar_popdef])[]dnl
  {
  ]b4_tname[
  };
-]b4_tname_if([], [[#endif]])[
+#endif
+]])[

 #if ]b4_api_PREFIX[DEBUG][
 ]b4_integral_parser_table_define([rline], [b4_rline])[

  void
-  ]b4_parser_class[::yystack_print_ ()
+  ]b4_parser_class[::yy_stack_print_ () const
  {
    *yycdebug_ << "Stack now";
    for (stack_type::const_iterator
@@ -1545,7 +1599,7 @@ b4_dollar_popdef])[]dnl
  }

  void
-  ]b4_parser_class[::yy_reduce_print_ (int yyrule)
+  ]b4_parser_class[::yy_reduce_print_ (int yyrule) const
  {
    int yylno = yyrline_[yyrule];
    int yynrhs = yyr2_[yyrule];
@@ -21,7 +21,7 @@ m4_include(b4_skeletonsdir/[d.m4])
 b4_output_begin([b4_parser_file_name])
 b4_copyright([Skeleton implementation for Bison LALR(1) parsers in D],
             [2007-2012, 2019-2020])[
-
+]b4_disclaimer[
 ]b4_percent_define_ifdef([package], [module b4_percent_define_get([package]);
 ])[
 version(D_Version2) {
@@ -509,39 +509,53 @@ m4_popdef([b4_at_dollar])])dnl
        yytoken = yytranslate_ (yychar);]b4_parse_trace_if([[
        yy_symbol_print ("Next token is", yytoken, yylval]b4_locations_if([, yylloc])[);]])[

-        /* If the proper action on seeing token YYTOKEN is to reduce or to
-           detect an error, take that action.  */
-        yyn += yytoken;
-        if (yyn < 0 || yylast_ < yyn || yycheck_[yyn] != yytoken)
-          label = YYDEFAULT;
-
-        /* <= 0 means reduce or error.  */
-        else if ((yyn = yytable_[yyn]) <= 0)
+        if (yytoken == SymbolKind.]b4_symbol(1, kind)[)
        {
-          if (yy_table_value_is_error_ (yyn))
-            label = YYERRLAB;
-          else
-          {
-            yyn = -yyn;
-            label = YYREDUCE;
-          }
+          // The scanner already issued an error message, process directly
+          // to error recovery.  But do not keep the error token as
+          // lookahead, it is too special and may lead us to an endless
+          // loop in error recovery. */
+          yychar = TokenKind.YYUNDEF;
+          yytoken = SymbolKind.]b4_symbol_prefix[YYUNDEF;]b4_locations_if([[
+          yyerrloc = yylloc;]])[
+          label = YYERRLAB1;
        }
        else
        {
-          /* Shift the lookahead token.  */]b4_parse_trace_if([[
-          yy_symbol_print ("Shifting", yytoken, yylval]b4_locations_if([, yylloc])[);]])[
+          /* If the proper action on seeing token YYTOKEN is to reduce or to
+             detect an error, take that action.  */
+          yyn += yytoken;
+          if (yyn < 0 || yylast_ < yyn || yycheck_[yyn] != yytoken)
+            label = YYDEFAULT;

-          /* Discard the token being shifted.  */
-          yychar = TokenKind.YYEMPTY;
+          /* <= 0 means reduce or error.  */
+          else if ((yyn = yytable_[yyn]) <= 0)
+          {
+            if (yy_table_value_is_error_ (yyn))
+              label = YYERRLAB;
+            else
+            {
+              yyn = -yyn;
+              label = YYREDUCE;
+            }
+          }
+          else
+          {
+            /* Shift the lookahead token.  */]b4_parse_trace_if([[
+            yy_symbol_print ("Shifting", yytoken, yylval]b4_locations_if([, yylloc])[);]])[

-          /* Count tokens shifted since error; after three, turn off error
-           * status.  */
-          if (yyerrstatus_ > 0)
-            --yyerrstatus_;
+            /* Discard the token being shifted.  */
+            yychar = TokenKind.YYEMPTY;

-          yystate = yyn;
-          yystack.push (yystate, yylval]b4_locations_if([, yylloc])[);
-          label = YYNEWSTATE;
+            /* Count tokens shifted since error; after three, turn off error
+             * status.  */
+            if (yyerrstatus_ > 0)
+              --yyerrstatus_;
+
+            yystate = yyn;
+            yystack.push (yystate, yylval]b4_locations_if([, yylloc])[);
+            label = YYNEWSTATE;
+          }
        }
        break;

@@ -577,8 +591,8 @@ m4_popdef([b4_at_dollar])])dnl
            yytoken = SymbolKind.]b4_symbol(-2, kind)[;
          yyerror (]b4_locations_if([yylloc, ])[yysyntax_error (yystate, yytoken));
        }
-
-]b4_locations_if([        yyerrloc = yylloc;])[
+]b4_locations_if([
+        yyerrloc = yylloc;])[
        if (yyerrstatus_ == 3)
        {
          /* If just tried and failed to reuse lookahead token after an
@@ -624,8 +638,8 @@ m4_popdef([b4_at_dollar])])dnl
          yyn = yypact_[yystate];
          if (!yy_pact_value_is_default_ (yyn))
          {
-            yyn += SymbolKind.]b4_symbol_prefix[YYERROR;
-            if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == SymbolKind.]b4_symbol_prefix[YYERROR)
+            yyn += SymbolKind.]b4_symbol(1, kind)[;
+            if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == SymbolKind.]b4_symbol(1, kind)[)
            {
              yyn = yytable_[yyn];
              if (0 < yyn)
@@ -731,14 +745,14 @@ m4_popdef([b4_at_dollar])])dnl
        int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
        int count = 0;
        for (int x = yyxbegin; x < yyxend; ++x)
-          if (yycheck_[x + yyn] == x && x != SymbolKind.]b4_symbol_prefix[YYERROR
+          if (yycheck_[x + yyn] == x && x != SymbolKind.]b4_symbol(1, kind)[
              && !yy_table_value_is_error_ (yytable_[x + yyn]))
             ++count;
          if (count < 5)
          {
             count = 0;
             for (int x = yyxbegin; x < yyxend; ++x)
-               if (yycheck_[x + yyn] == x && x != SymbolKind.]b4_symbol_prefix[YYERROR
+               if (yycheck_[x + yyn] == x && x != SymbolKind.]b4_symbol(1, kind)[
                   && !yy_table_value_is_error_ (yytable_[x + yyn]))
               {
                  res ~= count++ == 0 ? ", expecting " : " or ";
@@ -78,6 +78,7 @@ m4_define([b4_define_state],[[
 ]b4_output_begin([b4_parser_file_name])[
 ]b4_copyright([Skeleton implementation for Bison LALR(1) parsers in Java],
              [2007-2015, 2018-2020])[
+]b4_disclaimer[
 ]b4_percent_define_ifdef([package], [package b4_percent_define_get([package]);[
 ]])[
 ]b4_user_pre_prologue[
@@ -120,7 +121,7 @@ import java.text.MessageFormat;
   * Locations represent a part of the input through the beginning
   * and ending positions.
   */
-  public class ]b4_location_type[ {
+  public static class ]b4_location_type[ {
    /**
     * The first, inclusive, position in the range.
     */
@@ -163,12 +164,12 @@ import java.text.MessageFormat;
    }
  }

-  private ]b4_location_type[ yylloc (YYStack rhs, int n)
+  private ]b4_location_type[ yylloc(YYStack rhs, int n)
  {
    if (0 < n)
-      return new ]b4_location_type[ (rhs.locationAt (n-1).begin, rhs.locationAt (0).end);
+      return new ]b4_location_type[(rhs.locationAt(n-1).begin, rhs.locationAt(0).end);
    else
-      return new ]b4_location_type[ (rhs.locationAt (0).end);
+      return new ]b4_location_type[(rhs.locationAt(0).end);
  }]])[

 ]b4_declare_symbol_enum[
@@ -179,27 +180,26 @@ import java.text.MessageFormat;
   */
  public interface Lexer {
 ]b4_token_enums[
-    /** Deprecated, use b4_symbol(0, id) instead.  */
+    /** Deprecated, use ]b4_symbol(0, id)[ instead.  */
    public static final int EOF = ]b4_symbol(0, id)[;
-
-]b4_locations_if([[
+]b4_pull_if([b4_locations_if([[
    /**
     * Method to retrieve the beginning position of the last scanned token.
     * @@return the position at which the last scanned token starts.
     */
-    ]b4_position_type[ getStartPos ();
+    ]b4_position_type[ getStartPos();

    /**
     * Method to retrieve the ending position of the last scanned token.
     * @@return the first position beyond the last scanned token.
     */
-    ]b4_position_type[ getEndPos ();]])[
+    ]b4_position_type[ getEndPos();]])[

    /**
     * Method to retrieve the semantic value of the last scanned token.
     * @@return the semantic value of the last scanned token.
     */
-    ]b4_yystype[ getLVal ();
+    ]b4_yystype[ getLVal();

    /**
     * Entry point for the scanner.  Returns the token identifier corresponding
@@ -207,24 +207,25 @@ import java.text.MessageFormat;
     * ]b4_locations_if([and beginning/ending positions ])[of the token.
     * @@return the token identifier corresponding to the next token.
     */
-    int yylex ()]b4_maybe_throws([b4_lex_throws])[;
-
+    int yylex()]b4_maybe_throws([b4_lex_throws])[;
+]])[
    /**
-     * Entry point for error reporting.  Emits an error
-     * ]b4_locations_if([referring to the given location ])[in a user-defined way.
+     * Emit an error]b4_locations_if([ referring to the given location])[in a user-defined way.
     *
     *]b4_locations_if([[ @@param loc The location of the element to which the
-     *                error message is related]])[
+     *                error message is related.]])[
     * @@param msg The string for the error message.
     */
-     void yyerror (]b4_locations_if([b4_location_type[ loc, ]])[String msg);
+     void yyerror(]b4_locations_if([b4_location_type[ loc, ]])[String msg);

 ]b4_parse_error_bmatch(
           [custom], [[
    /**
-     * Build and emit a syntax error message.
+     * Build and emit a "syntax error" message in a user-defined way.
+     *
+     * @@param ctx  The context of the error.
     */
-     void reportSyntaxError (][Context yyctx);
+     void reportSyntaxError (][Context ctx);
 ]])[
  }

@@ -306,9 +307,8 @@ import java.text.MessageFormat;
   *]b4_locations_if([[ Use a <code>null</code> location.]])[
   * @@param msg The error message.
   */
-  public final void yyerror (String msg)
-  {
-    yylexer.yyerror (]b4_locations_if([[(]b4_location_type[)null, ]])[msg);
+  public final void yyerror(String msg) {
+      yylexer.yyerror(]b4_locations_if([[(]b4_location_type[)null, ]])[msg);
  }
 ]b4_locations_if([[
  /**
@@ -316,9 +316,8 @@ import java.text.MessageFormat;
   * @@param loc The location associated with the message.
   * @@param msg The error message.
   */
-  public final void yyerror (]b4_location_type[ loc, String msg)
-  {
-    yylexer.yyerror (loc, msg);
+  public final void yyerror(]b4_location_type[ loc, String msg) {
+      yylexer.yyerror(loc, msg);
  }

  /**
@@ -326,9 +325,8 @@ import java.text.MessageFormat;
   * @@param pos The position associated with the message.
   * @@param msg The error message.
   */
-  public final void yyerror (]b4_position_type[ pos, String msg)
-  {
-    yylexer.yyerror (new ]b4_location_type[ (pos), msg);
+  public final void yyerror(]b4_position_type[ pos, String msg) {
+      yylexer.yyerror(new ]b4_location_type[ (pos), msg);
  }]])[
 ]b4_parse_trace_if([[
  protected final void yycdebug (String s) {
@@ -468,7 +466,7 @@ import java.text.MessageFormat;
      return yydefgoto_[yysym - YYNTOKENS_];
  }

-  private int yyaction (int yyn, YYStack yystack, int yylen)]b4_maybe_throws([b4_throws])[
+  private int yyaction(int yyn, YYStack yystack, int yylen)]b4_maybe_throws([b4_throws])[
  {
    /* If YYLEN is nonzero, implement the default value of the action:
       '$$ = $1'.  Otherwise, use the top of the stack.
@@ -476,10 +474,10 @@ import java.text.MessageFormat;
       Otherwise, the following line sets YYVAL to garbage.
       This behavior is undocumented and Bison
       users should not rely upon it.  */
-    ]b4_yystype[ yyval = (0 < yylen) ? yystack.valueAt (yylen - 1) : yystack.valueAt (0);]b4_locations_if([[
-    ]b4_location_type[ yyloc = yylloc (yystack, yylen);]])[]b4_parse_trace_if([[
+    ]b4_yystype[ yyval = (0 < yylen) ? yystack.valueAt(yylen - 1) : yystack.valueAt(0);]b4_locations_if([[
+    ]b4_location_type[ yyloc = yylloc(yystack, yylen);]])[]b4_parse_trace_if([[

-    yyReducePrint (yyn, yystack);]])[
+    yyReducePrint(yyn, yystack);]])[

    switch (yyn)
      {
@@ -487,13 +485,13 @@ import java.text.MessageFormat;
        default: break;
      }]b4_parse_trace_if([[

-    yySymbolPrint ("-> $$ =", SymbolKind.get (yyr1_[yyn]), yyval]b4_locations_if([, yyloc])[);]])[
+    yySymbolPrint("-> $$ =", SymbolKind.get(yyr1_[yyn]), yyval]b4_locations_if([, yyloc])[);]])[

-    yystack.pop (yylen);
+    yystack.pop(yylen);
    yylen = 0;
    /* Shift the result of the reduction.  */
-    int yystate = yyLRGotoState (yystack.stateAt (0), yyr1_[yyn]);
-    yystack.push (yystate, yyval]b4_locations_if([, yyloc])[);
+    int yystate = yyLRGotoState(yystack.stateAt(0), yyr1_[yyn]);
+    yystack.push(yystate, yyval]b4_locations_if([, yyloc])[);
    return YYNEWSTATE;
  }

@@ -503,13 +501,14 @@ import java.text.MessageFormat;
  `--------------------------------*/

  private void yySymbolPrint(String s, SymbolKind yykind,
-                             ]b4_yystype[ yyvalue]b4_locations_if([, ]b4_location_type[ yylocation])[)
-  {
-    yycdebug (s
-              + (yykind.getCode() < YYNTOKENS_ ? " token " : " nterm ")
-              + yykind.getName() + " ("]b4_locations_if([
-              + yylocation + ": "])[
-              + (yyvalue == null ? "(null)" : yyvalue.toString()) + ")");
+                             ]b4_yystype[ yyvalue]b4_locations_if([, ]b4_location_type[ yylocation])[) {
+      if (0 < yydebug) {
+          yycdebug(s
+                   + (yykind.getCode() < YYNTOKENS_ ? " token " : " nterm ")
+                   + yykind.getName() + " ("]b4_locations_if([
+                   + yylocation + ": "])[
+                   + (yyvalue == null ? "(null)" : yyvalue.toString()) + ")");
+      }
  }]])[

 ]b4_push_if([],[[
@@ -520,7 +519,7 @@ import java.text.MessageFormat;
   * @@return <tt>true</tt> if the parsing succeeds.  Note that this does not
   *          imply that there were no syntax errors.
   */
-  public boolean parse ()]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[]])[
+  public boolean parse()]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[]])[
 ]b4_push_if([
  /**
   * Push Parse input from external lexer
@@ -531,7 +530,7 @@ import java.text.MessageFormat;
   *
   * @@return <tt>YYACCEPT, YYABORT, YYPUSH_MORE</tt>
   */
-  public int push_parse (int yylextoken, b4_yystype yylexval[]b4_locations_if([, b4_location_type yylexloc]))b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])])[
+  public int push_parse(int yylextoken, b4_yystype yylexval[]b4_locations_if([, b4_location_type yylexloc]))b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])])[
  {]b4_locations_if([[
    /* @@$.  */
    ]b4_location_type[ yyloc;]])[
@@ -611,44 +610,58 @@ b4_dollar_popdef[]dnl

        /* Convert token to internal form.  */
        yytoken = yytranslate_ (yychar);]b4_parse_trace_if([[
-        yySymbolPrint ("Next token is", yytoken,
-                       yylval]b4_locations_if([, yylloc])[);]])[
+        yySymbolPrint("Next token is", yytoken,
+                      yylval]b4_locations_if([, yylloc])[);]])[

-        /* If the proper action on seeing token YYTOKEN is to reduce or to
-           detect an error, take that action.  */
-        yyn += yytoken.getCode ();
-        if (yyn < 0 || YYLAST_ < yyn || yycheck_[yyn] != yytoken.getCode ())
-          label = YYDEFAULT;
-
-        /* <= 0 means reduce or error.  */
-        else if ((yyn = yytable_[yyn]) <= 0)
+        if (yytoken == SymbolKind.]b4_symbol_prefix[YYerror)
          {
-            if (yyTableValueIsError (yyn))
-              label = YYERRLAB;
-            else
-              {
-                yyn = -yyn;
-                label = YYREDUCE;
-              }
+            // The scanner already issued an error message, process directly
+            // to error recovery.  But do not keep the error token as
+            // lookahead, it is too special and may lead us to an endless
+            // loop in error recovery. */
+            yychar = Lexer.]b4_percent_define_get([api.token.prefix])[YYUNDEF;
+            yytoken = SymbolKind.]b4_symbol_prefix[YYUNDEF;]b4_locations_if([[
+            yyerrloc = yylloc;]])[
+            label = YYERRLAB1;
          }
-
        else
          {
-            /* Shift the lookahead token.  */]b4_parse_trace_if([[
-            yySymbolPrint ("Shifting", yytoken,
-                           yylval]b4_locations_if([, yylloc])[);
+            /* If the proper action on seeing token YYTOKEN is to reduce or to
+               detect an error, take that action.  */
+            yyn += yytoken.getCode ();
+            if (yyn < 0 || YYLAST_ < yyn || yycheck_[yyn] != yytoken.getCode ())
+              label = YYDEFAULT;
+
+            /* <= 0 means reduce or error.  */
+            else if ((yyn = yytable_[yyn]) <= 0)
+              {
+                if (yyTableValueIsError (yyn))
+                  label = YYERRLAB;
+                else
+                  {
+                    yyn = -yyn;
+                    label = YYREDUCE;
+                  }
+              }
+
+            else
+              {
+                /* Shift the lookahead token.  */]b4_parse_trace_if([[
+                yySymbolPrint("Shifting", yytoken,
+                              yylval]b4_locations_if([, yylloc])[);
 ]])[
-            /* Discard the token being shifted.  */
-            yychar = YYEMPTY_;
+                /* Discard the token being shifted.  */
+                yychar = YYEMPTY_;

-            /* Count tokens shifted since error; after three, turn off error
-               status.  */
-            if (yyerrstatus_ > 0)
-              --yyerrstatus_;
+                /* Count tokens shifted since error; after three, turn off error
+                   status.  */
+                if (yyerrstatus_ > 0)
+                  --yyerrstatus_;

-            yystate = yyn;
-            yystack.push (yystate, yylval]b4_locations_if([, yylloc])[);
-            label = YYNEWSTATE;
+                yystate = yyn;
+                yystack.push (yystate, yylval]b4_locations_if([, yylloc])[);
+                label = YYNEWSTATE;
+              }
          }
        break;

@@ -668,7 +681,7 @@ b4_dollar_popdef[]dnl
      `-----------------------------*/
      case YYREDUCE:
        yylen = yyr2_[yyn];
-        label = yyaction (yyn, yystack, yylen);
+        label = yyaction(yyn, yystack, yylen);
        yystate = yystack.stateAt (0);
        break;

@@ -684,7 +697,6 @@ b4_dollar_popdef[]dnl
              yytoken = null;
            yyreportSyntaxError (new Context (yystack, yytoken]b4_locations_if([[, yylloc]])[));
          }
-
 ]b4_locations_if([[
        yyerrloc = yylloc;]])[
        if (yyerrstatus_ == 3)
@@ -732,9 +744,9 @@ b4_dollar_popdef[]dnl
            yyn = yypact_[yystate];
            if (!yyPactValueIsDefault (yyn))
              {
-                yyn += SymbolKind.]b4_symbol_prefix[YYERROR.getCode ();
+                yyn += SymbolKind.]b4_symbol(1, kind)[.getCode ();
                if (0 <= yyn && yyn <= YYLAST_
-                    && yycheck_[yyn] == SymbolKind.]b4_symbol_prefix[YYERROR.getCode ())
+                    && yycheck_[yyn] == SymbolKind.]b4_symbol(1, kind)[.getCode ())
                  {
                    yyn = yytable_[yyn];
                    if (0 < yyn)
@@ -767,8 +779,8 @@ b4_dollar_popdef[]dnl
        yystack.pop (2);]])[

        /* Shift the error token.  */]b4_parse_trace_if([[
-        yySymbolPrint ("Shifting", SymbolKind.get (yystos_[yyn]),
-                       yylval]b4_locations_if([, yyloc])[);]])[
+        yySymbolPrint("Shifting", SymbolKind.get (yystos_[yyn]),
+                      yylval]b4_locations_if([, yyloc])[);]])[

        yystate = yyn;
        yystack.push (yyn, yylval]b4_locations_if([, yyloc])[);
@@ -819,7 +831,7 @@ b4_dollar_popdef[]dnl
    this.push_parse_initialized = true;

  }
-]b4_locations_if([
+]b4_locations_if([[
  /**
   * Push parse given input from an external lexer.
   *
@@ -829,36 +841,32 @@ b4_dollar_popdef[]dnl
   *
   * @@return <tt>YYACCEPT, YYABORT, YYPUSH_MORE</tt>
   */
-  public int push_parse (int yylextoken, b4_yystype yylexval, b4_position_type yylexpos)b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])
-  {
-    return push_parse (yylextoken, yylexval, new b4_location_type (yylexpos));
+  public int push_parse(int yylextoken, ]b4_yystype[ yylexval, ]b4_position_type[ yylexpos)]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[ {
+      return push_parse(yylextoken, yylexval, new ]b4_location_type[(yylexpos));
  }
-])[]])[
+]])])[

 ]b4_both_if([[
  /**
   * Parse input from the scanner that was specified at object construction
   * time.  Return whether the end of the input was reached successfully.
-   * This version of parse () is defined only when api.push-push=both.
+   * This version of parse() is defined only when api.push-push=both.
   *
   * @@return <tt>true</tt> if the parsing succeeds.  Note that this does not
   *          imply that there were no syntax errors.
   */
-  public boolean parse ()]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[
-  {
-    if (yylexer == null)
-      throw new NullPointerException("Null Lexer");
-    int status;
-    do {
-      int token = yylexer.yylex();
-      ]b4_yystype[ lval = yylexer.getLVal();
-]b4_locations_if([dnl
-      b4_location_type yyloc = new b4_location_type (yylexer.getStartPos (),
-                                            yylexer.getEndPos ());])[]b4_locations_if([[
-      status = push_parse(token,lval,yyloc);]], [[
-      status = push_parse(token,lval);]])[
-    } while (status == YYPUSH_MORE);
-    return (status == YYACCEPT);
+  public boolean parse()]b4_maybe_throws([b4_list2([b4_lex_throws], [b4_throws])])[ {
+      if (yylexer == null)
+          throw new NullPointerException("Null Lexer");
+      int status;
+      do {
+          int token = yylexer.yylex();
+          ]b4_yystype[ lval = yylexer.getLVal();]b4_locations_if([[
+          ]b4_location_type[ yyloc = new ]b4_location_type[(yylexer.getStartPos(), yylexer.getEndPos());
+          status = push_parse(token, lval, yyloc);]], [[
+          status = push_parse(token, lval);]])[
+      } while (status == YYPUSH_MORE);
+      return status == YYACCEPT;
  }
 ]])[

@@ -925,7 +933,7 @@ b4_dollar_popdef[]dnl
          int yychecklim = YYLAST_ - yyn + 1;
          int yyxend = yychecklim < NTOKENS ? yychecklim : NTOKENS;
          for (int yyx = yyxbegin; yyx < yyxend; ++yyx)
-            if (yycheck_[yyx + yyn] == yyx && yyx != SymbolKind.]b4_symbol_prefix[YYERROR.getCode ()
+            if (yycheck_[yyx + yyn] == yyx && yyx != SymbolKind.]b4_symbol(1, kind)[.getCode ()
                && !yyTableValueIsError (yytable_[yyx + yyn]))
              {
                if (yyarg == null)
@@ -936,6 +944,8 @@ b4_dollar_popdef[]dnl
                  yyarg[yycount++] = SymbolKind.get (yyx);
              }
        }
+      if (yyarg != null && yycount == yyoffset && yyoffset < yyargn)
+        yyarg[yycount] = null;
      return yycount - yyoffset;
    }
  }
@@ -982,39 +992,39 @@ b4_dollar_popdef[]dnl
  }
 ]])[

-/**
-   * Report a syntax error.
+  /**
+   * Build and emit a "syntax error" message in a user-defined way.
+   *
+   * @@param ctx  The context of the error.
   */
-  private void yyreportSyntaxError (Context yyctx)
-  {]b4_parse_error_bmatch(
+  private void yyreportSyntaxError(Context yyctx) {]b4_parse_error_bmatch(
 [custom], [[
-    yylexer.reportSyntaxError (yyctx);]],
+      yylexer.reportSyntaxError(yyctx);]],
 [detailed\|verbose], [[
-    if (yyErrorVerbose)
-      {
-        final int argmax = 5;
-        SymbolKind[] yyarg = new SymbolKind[argmax];
-        int yycount = yysyntaxErrorArguments (yyctx, yyarg, argmax);
-        String[] yystr = new String[yycount];
-        for (int yyi = 0; yyi < yycount; ++yyi)
-          yystr[yyi] = yyarg[yyi].getName();
-        String yyformat;
-        switch (yycount)
-          {
-            default:
-            case 0: yyformat = ]b4_trans(["syntax error"])[; break;
-            case 1: yyformat = ]b4_trans(["syntax error, unexpected {0}"])[; break;
-            case 2: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1}"])[; break;
-            case 3: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2}"])[; break;
-            case 4: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2} or {3}"])[; break;
-            case 5: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2} or {3} or {4}"])[; break;
+      if (yyErrorVerbose) {
+          final int argmax = 5;
+          SymbolKind[] yyarg = new SymbolKind[argmax];
+          int yycount = yysyntaxErrorArguments(yyctx, yyarg, argmax);
+          String[] yystr = new String[yycount];
+          for (int yyi = 0; yyi < yycount; ++yyi) {
+              yystr[yyi] = yyarg[yyi].getName();
          }
-        yyerror (]b4_locations_if([[yyctx.yylocation, ]])[new MessageFormat (yyformat).format (yystr));
-        return;
-      }
-    yyerror (]b4_locations_if([[yyctx.yylocation, ]])["syntax error");]],
+          String yyformat;
+          switch (yycount) {
+              default:
+              case 0: yyformat = ]b4_trans(["syntax error"])[; break;
+              case 1: yyformat = ]b4_trans(["syntax error, unexpected {0}"])[; break;
+              case 2: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1}"])[; break;
+              case 3: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2}"])[; break;
+              case 4: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2} or {3}"])[; break;
+              case 5: yyformat = ]b4_trans(["syntax error, unexpected {0}, expecting {1} or {2} or {3} or {4}"])[; break;
+          }
+          yyerror(]b4_locations_if([[yyctx.yylocation, ]])[new MessageFormat(yyformat).format(yystr));
+      } else {
+          yyerror(]b4_locations_if([[yyctx.yylocation, ]])[]b4_trans(["syntax error"])[);
+      }]],
 [simple], [[
-    yyerror (]b4_locations_if([[yyctx.yylocation, ]])["syntax error");]])[
+      yyerror(]b4_locations_if([[yyctx.yylocation, ]])[]b4_trans(["syntax error"])[);]])[
  }

  /**
@@ -1060,10 +1070,10 @@ b4_dollar_popdef[]dnl

    /* The symbols being reduced.  */
    for (int yyi = 0; yyi < yynrhs; yyi++)
-      yySymbolPrint ("   $" + (yyi + 1) + " =",
-                     SymbolKind.get (yystos_[yystack.stateAt (yynrhs - (yyi + 1))]),
-                     ]b4_rhs_data(yynrhs, yyi + 1)b4_locations_if([,
-                     b4_rhs_location(yynrhs, yyi + 1)])[);
+      yySymbolPrint("   $" + (yyi + 1) + " =",
+                    SymbolKind.get (yystos_[yystack.stateAt (yynrhs - (yyi + 1))]),
+                    ]b4_rhs_data(yynrhs, yyi + 1)b4_locations_if([,
+                    b4_rhs_location(yynrhs, yyi + 1)])[);
  }]])[

  /* YYTRANSLATE_(TOKEN-NUM) -- Symbol number corresponding to TOKEN-NUM
@@ -41,6 +41,13 @@ m4_define([b4_stack_define],
        : seq_ (n)
      {}

+#if 201103L <= YY_CPLUSPLUS
+      /// Non copyable.
+      stack (const stack&) = delete;
+      /// Non copyable.
+      stack& operator= (const stack&) = delete;
+#endif
+
      /// Random access.
      ///
      /// Index 0 returns the topmost element.
@@ -126,8 +133,12 @@ m4_define([b4_stack_define],
      };

    private:
+#if YY_CPLUSPLUS < 201103L
+      /// Non copyable.
      stack (const stack&);
+      /// Non copyable.
      stack& operator= (const stack&);
+#endif
      /// The wrapped container.
      S seq_;
    };
@@ -115,6 +115,13 @@ m4_define([b4_value_type_declare],
      new (yyas_<T> ()) T (YY_MOVE (t));
    }

+#if 201103L <= YY_CPLUSPLUS
+    /// Non copyable.
+    semantic_type (const self_type&) = delete;
+    /// Non copyable.
+    self_type& operator= (const self_type&) = delete;
+#endif
+
    /// Destruction, allowed only if empty.
    ~semantic_type () YY_NOEXCEPT
    {]b4_parse_assert_if([
@@ -258,9 +265,12 @@ m4_define([b4_value_type_declare],
    }

  private:
-    /// Prohibit blind copies.
-    self_type& operator= (const self_type&);
+#if YY_CPLUSPLUS < 201103L
+    /// Non copyable.
    semantic_type (const self_type&);
+    /// Non copyable.
+    self_type& operator= (const self_type&);
+#endif

    /// Accessor to raw memory as \a T.
    template <typename T>
@@ -132,6 +132,7 @@ m4_define([b4_rhs_value],
 # b4_lhs_location()
 # -----------------
 # Expansion of @$.
+# Overparenthetized to avoid obscure problems with "foo$$bar = foo$1bar".
 m4_define([b4_lhs_location],
 [(yyloc)])

@@ -140,6 +141,7 @@ m4_define([b4_lhs_location],
 # ---------------------------------
 # Expansion of @POS, where the current rule has RULE-LENGTH symbols
 # on RHS.
+# Overparenthetized to avoid obscure problems with "foo$$bar = foo$1bar".
 m4_define([b4_rhs_location],
 [(yylsp@{b4_subtract([$2], [$1])@})])

@@ -358,6 +360,7 @@ b4_output_begin([b4_parser_file_name])[
 /* C LALR(1) parser skeleton written by Richard Stallman, by
   simplifying the original so-called "semantic" parser.  */

+]b4_disclaimer[
 /* All symbols defined below should begin with yy or YY, to avoid
   infringing on user name space.  This should be done even for local
   variables, as they might otherwise be expanded by user macros.
@@ -365,7 +368,6 @@ b4_output_begin([b4_parser_file_name])[
   define necessary library symbols; they are noted "INFRINGES ON
   USER NAME SPACE" below.  */

-]b4_disclaimer[
 ]b4_identification[
 ]b4_percent_code_get([[top]])[]dnl
 m4_if(b4_api_prefix, [yy], [],
@@ -401,50 +403,10 @@ m4_if(b4_api_prefix, [yy], [],
 ]b4_declare_symbol_enum[

 ]b4_user_post_prologue[
-]b4_percent_code_get[]dnl
-
-[#ifdef short
-# undef short
-#endif
-
+]b4_percent_code_get[
 ]b4_c99_int_type_define[

-#ifndef YYPTRDIFF_T
-# if defined __PTRDIFF_TYPE__ && defined __PTRDIFF_MAX__
-#  define YYPTRDIFF_T __PTRDIFF_TYPE__
-#  define YYPTRDIFF_MAXIMUM __PTRDIFF_MAX__
-# elif defined PTRDIFF_MAX
-#  ifndef ptrdiff_t
-#   include <stddef.h> /* INFRINGES ON USER NAME SPACE */
-#  endif
-#  define YYPTRDIFF_T ptrdiff_t
-#  define YYPTRDIFF_MAXIMUM PTRDIFF_MAX
-# else
-#  define YYPTRDIFF_T long
-#  define YYPTRDIFF_MAXIMUM LONG_MAX
-# endif
-#endif
-
-#ifndef YYSIZE_T
-# ifdef __SIZE_TYPE__
-#  define YYSIZE_T __SIZE_TYPE__
-# elif defined size_t
-#  define YYSIZE_T size_t
-# elif defined __STDC_VERSION__ && 199901 <= __STDC_VERSION__
-#  include <stddef.h> /* INFRINGES ON USER NAME SPACE */
-#  define YYSIZE_T size_t
-# else
-#  define YYSIZE_T unsigned
-# endif
-#endif
-
-#define YYSIZE_MAXIMUM                                  \
-  YY_CAST (YYPTRDIFF_T,                                 \
-           (YYPTRDIFF_MAXIMUM < YY_CAST (YYSIZE_T, -1)  \
-            ? YYPTRDIFF_MAXIMUM                         \
-            : YY_CAST (YYSIZE_T, -1)))
-
-#define YYSIZEOF(X) YY_CAST (YYPTRDIFF_T, sizeof (X))
+]b4_sizes_types_define[

 /* Stored state numbers (used for stacks). */
 typedef ]b4_int_type(0, m4_eval(b4_states_number - 1))[ yy_state_t;
@@ -463,6 +425,11 @@ typedef int yy_state_fast_t;
 #  define YY_(Msgid) Msgid
 # endif
 #endif
+]b4_has_translations_if([
+#ifndef N_
+# define N_(Msgid) Msgid
+#endif
+])[

 ]b4_attribute_define[

@@ -542,7 +509,7 @@ void free (void *); /* INFRINGES ON USER NAME SPACE */
 #  endif
 # endif]b4_lac_if([[
 # define YYCOPY_NEEDED 1]])[
-#endif]b4_lac_if([], [b4_parse_error_case([simple], [[/* !defined yyoverflow */]])])[
+#endif /* ]b4_lac_if([[1]], [b4_parse_error_case([simple], [[!defined yyoverflow]], [[1]])])[ */

 #if (! defined yyoverflow \
     && (! defined __cplusplus \
@@ -676,8 +643,8 @@ yysymbol_name (yysymbol_kind_t yysymbol)
  static const char *const yy_sname[] =
  {
  ]b4_symbol_names[
-  };]m4_ifdef([b4_translatable], [[
-  /* YYTRANSLATABLE[SYMBOL-NUM] -- Whether YYTNAME[SYMBOL-NUM] is
+  };]b4_has_translations_if([[
+  /* YYTRANSLATABLE[SYMBOL-NUM] -- Whether YY_SNAME[SYMBOL-NUM] is
     internationalizable.  */
  static ]b4_int_type_for([b4_translatable])[ yytranslatable[] =
  {
@@ -690,14 +657,14 @@ yysymbol_name (yysymbol_kind_t yysymbol)
 }]])[
 #endif

-# ifdef YYPRINT
+#ifdef YYPRINT
 /* YYTOKNUM[NUM] -- (External) token number corresponding to the
   (internal) symbol number NUM (which must be that of a token).  */
 static const ]b4_int_type_for([b4_toknum])[ yytoknum[] =
 {
  ]b4_toknum[
 };
-# endif
+#endif

 #define YYPACT_NINF (]b4_pact_ninf[)

@@ -741,6 +708,9 @@ enum { YYENOMEM = -2 };
      }                                                           \
  while (0)

+/* Backward compatibility with an undocumented macro.
+   Use ]b4_symbol(1, id)[ or ]b4_symbol(2, id)[. */
+#define YYERRCODE ]b4_symbol(2, id)[
 ]b4_locations_if([[
 ]b4_yylloc_default_define[
 #define YYRHSLOC(Rhs, K) ((Rhs)[K])
@@ -762,13 +732,13 @@ do {                                            \

 ]b4_yy_location_print_define[

-# define YY_SYMBOL_PRINT(Title, Type, Value, Location)                    \
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)                    \
 do {                                                                      \
  if (yydebug)                                                            \
    {                                                                     \
      YYFPRINTF (stderr, "%s ", Title);                                   \
      yy_symbol_print (stderr,                                            \
-                  Type, Value]b4_locations_if([, Location])[]b4_user_args[); \
+                  Kind, Value]b4_locations_if([, Location])[]b4_user_args[); \
      YYFPRINTF (stderr, "\n");                                           \
    }                                                                     \
 } while (0)
@@ -818,9 +788,8 @@ yy_reduce_print (yy_state_t *yyssp, YYSTYPE *yyvsp,]b4_locations_if([[ YYLTYPE *
      YYFPRINTF (stderr, "   $%d = ", yyi + 1);
      yy_symbol_print (stderr,
                       YY_ACCESSING_SYMBOL (+yyssp[yyi + 1 - yynrhs]),
-                       &]b4_rhs_value(yynrhs, yyi + 1)[
-                       ]b4_locations_if([, &]b4_rhs_location(yynrhs, yyi + 1))[]dnl
-                       b4_user_args[);
+                       &]b4_rhs_value(yynrhs, yyi + 1)[]b4_locations_if([,
+                       &]b4_rhs_location(yynrhs, yyi + 1))[]b4_user_args[);
      YYFPRINTF (stderr, "\n");
    }
 }
@@ -836,7 +805,7 @@ do {                                    \
 int yydebug;
 #else /* !]b4_api_PREFIX[DEBUG */
 # define YYDPRINTF(Args) ((void) 0)
-# define YY_SYMBOL_PRINT(Title, Type, Value, Location)
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)
 # define YY_STACK_PRINT(Bottom, Top)
 # define YY_REDUCE_PRINT(Rule)
 #endif /* !]b4_api_PREFIX[DEBUG */
@@ -1149,7 +1118,7 @@ yypcontext_expected_tokens (const yypcontext_t *yyctx,
  for (yyx = 0; yyx < YYNTOKENS; ++yyx)
    {
      yysymbol_kind_t yysym = YY_CAST (yysymbol_kind_t, yyx);
-      if (yysym != ]b4_symbol_prefix[YYERROR && yysym != ]b4_symbol_prefix[YYUNDEF)
+      if (yysym != ]b4_symbol(1, kind)[ && yysym != ]b4_symbol_prefix[YYUNDEF)
        switch (yy_lac (]b4_push_if([[yyps->yyesa, &yyps->yyes, &yyps->yyes_capacity, yyps->yyssp, yysym]],
                                    [[yyctx->yyesa, yyctx->yyes, yyctx->yyes_capacity, yyctx->yyssp, yysym]])[))
          {
@@ -1178,7 +1147,7 @@ yypcontext_expected_tokens (const yypcontext_t *yyctx,
      int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
      int yyx;
      for (yyx = yyxbegin; yyx < yyxend; ++yyx)
-        if (yycheck[yyx + yyn] == yyx && yyx != ]b4_symbol_prefix[YYERROR
+        if (yycheck[yyx + yyn] == yyx && yyx != ]b4_symbol(1, kind)[
            && !yytable_value_is_error (yytable[yyx + yyn]))
          {
            if (!yyarg)
@@ -1189,6 +1158,8 @@ yypcontext_expected_tokens (const yypcontext_t *yyctx,
              yyarg[yycount++] = YY_CAST (yysymbol_kind_t, yyx);
          }
    }]])[
+  if (yyarg && yycount == 0 && 0 < yyargn)
+    yyarg[0] = ]b4_symbol(-2, kind)[;
  return yycount;
 }

@@ -1400,10 +1371,10 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,

  switch (yycount)
    {
-# define YYCASE_(N, S)                      \
+#define YYCASE_(N, S)                       \
      case N:                               \
        yyformat = S;                       \
-      break
+        break
    default: /* Avoid compiler warnings. */
      YYCASE_(0, YY_("syntax error"));
      YYCASE_(1, YY_("syntax error, unexpected %s"));
@@ -1411,7 +1382,7 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
      YYCASE_(3, YY_("syntax error, unexpected %s, expecting %s or %s"));
      YYCASE_(4, YY_("syntax error, unexpected %s, expecting %s or %s or %s"));
      YYCASE_(5, YY_("syntax error, unexpected %s, expecting %s or %s or %s or %s"));
-# undef YYCASE_
+#undef YYCASE_
    }

  /* Compute error message size.  Don't count the "%s"s, but reserve
@@ -1693,7 +1664,7 @@ yysetstate:
        YYSTACK_RELOCATE (yyss_alloc, yyss);
        YYSTACK_RELOCATE (yyvs_alloc, yyvs);]b4_locations_if([
        YYSTACK_RELOCATE (yyls_alloc, yyls);])[
-# undef YYSTACK_RELOCATE
+#  undef YYSTACK_RELOCATE
        if (yyss1 != yyssa)
          YYSTACK_FREE (yyss1);
      }
@@ -1765,6 +1736,17 @@ yyread_pushed_token:]])[
      yytoken = ]b4_symbol(0, [kind])[;
      YYDPRINTF ((stderr, "Now at end of input.\n"));
    }
+  else if (yychar == ]b4_symbol(1, [id])[)
+    {
+      /* The scanner already issued an error message, process directly
+         to error recovery.  But do not keep the error token as
+         lookahead, it is too special and may lead us to an endless
+         loop in error recovery. */
+      yychar = ]b4_symbol(2, [id])[;
+      yytoken = ]b4_symbol(1, [kind])[;]b4_locations_if([[
+      yyerror_range[1] = yylloc;]])[
+      goto yyerrlab1;
+    }
  else
    {
      yytoken = YYTRANSLATE (yychar);
@@ -1947,9 +1929,8 @@ yyerrlab:
          goto yyexhaustedlab;
      }]])[
    }
-
-]b4_locations_if([[  yyerror_range[1] = yylloc;]])[
-
+]b4_locations_if([[
+  yyerror_range[1] = yylloc;]])[
  if (yyerrstatus == 3)
    {
      /* If just tried and failed to reuse lookahead token after an
@@ -1998,14 +1979,14 @@ yyerrorlab:
 yyerrlab1:
  yyerrstatus = 3;      /* Each real token shifted decrements this.  */

-  // Pop stack until we find a state that shifts the error token.
+  /* Pop stack until we find a state that shifts the error token.  */
  for (;;)
    {
      yyn = yypact[yystate];
      if (!yypact_value_is_default (yyn))
        {
-          yyn += ]b4_symbol_prefix[YYERROR;
-          if (0 <= yyn && yyn <= YYLAST && yycheck[yyn] == ]b4_symbol_prefix[YYERROR)
+          yyn += ]b4_symbol(1, kind)[;
+          if (0 <= yyn && yyn <= YYLAST && yycheck[yyn] == ]b4_symbol(1, kind)[)
            {
              yyn = yytable[yyn];
              if (0 < yyn)
@@ -2034,10 +2015,8 @@ yyerrlab1:
  YY_IGNORE_MAYBE_UNINITIALIZED_END
 ]b4_locations_if([[
  yyerror_range[2] = yylloc;
-  /* Using YYLLOC is tempting, but would change the location of
-     the lookahead.  YYLOC is available though.  */
-  YYLLOC_DEFAULT (yyloc, yyerror_range, 2);
-  *++yylsp = yyloc;]])[
+  ++yylsp;
+  YYLLOC_DEFAULT (*yylsp, yyerror_range, 2);]])[

  /* Shift the error token.  */
  YY_SYMBOL_PRINT ("Shifting", YY_ACCESSING_SYMBOL (yyn), yyvsp, yylsp);
@@ -300,10 +300,7 @@ Bison Declarations
 Parser C-Language Interface

 * Parser Function::         How to call @code{yyparse} and what it returns.
-* Push Parser Function::    How to call @code{yypush_parse} and what it returns.
-* Pull Parser Function::    How to call @code{yypull_parse} and what it returns.
-* Parser Create Function::  How to call @code{yypstate_new} and what it returns.
-* Parser Delete Function::  How to call @code{yypstate_delete} and what it returns.
+* Push Parser Interface::   How to create, use, and destroy push parsers.
 * Lexical::                 You must supply a function @code{yylex}
                              which reads tokens.
 * Error Reporting::         Passing error messages to the user.
@@ -314,6 +311,7 @@ Parser C-Language Interface
 The Lexical Analyzer Function @code{yylex}

 * Calling Convention::  How @code{yyparse} calls @code{yylex}.
+* Special Tokens::      Signaling end-of-file and errors to the parser.
 * Tokens from Literals:: Finding token kinds from string aliases.
 * Token Values::        How @code{yylex} must return the semantic value
                          of the token it has read.
@@ -2368,9 +2366,9 @@ yylex (void)
@end group
@end example

-Basically, the lexical analyzer performs the same processing as before:
-it skips blanks and tabs, and reads numbers or single-character tokens.
-In addition, it updates @code{yylloc}, the global variable (of type
+Basically, the lexical analyzer performs the same processing as before: it
+skips blanks and tabs, and reads numbers or single-character tokens.  In
+addition, it updates @code{yylloc}, the global variable (of type
@code{YYLTYPE}) containing the token's location.

 Now, each time this function returns a token, the parser has its kind as
@@ -4504,12 +4502,17 @@ typedef struct YYLTYPE
@} YYLTYPE;
@end example

+While default locations represent a range in the source file(s), this is not
+a requirement.  It could be a single point or just a line number, or even
+more complex structures.
+
 When @code{YYLTYPE} is not defined, at the beginning of the parsing, Bison
 initializes all these fields to 1 for @code{yylloc}.  To initialize
@code{yylloc} with a custom location type (or to chose a different
 initialization), use the @code{%initial-action} directive.  @xref{Initial
 Action Decl}.

+
@node Actions and Locations
@subsection Actions and Locations
@cindex location actions
@@ -6131,7 +6134,7 @@ the @code{full} value was introduced in Bison 2.7
@deffn Directive {%define api.push-pull} @var{kind}

@itemize @bullet
-@item Language(s): C (deterministic parsers only)
+@item Language(s): C (deterministic parsers only), Java

@item Purpose: Request a pull parser, a push parser, or both.
@xref{Push Decl}.
@@ -6921,10 +6924,7 @@ in the grammar file, you are likely to run into trouble.

@menu
 * Parser Function::         How to call @code{yyparse} and what it returns.
-* Push Parser Function::    How to call @code{yypush_parse} and what it returns.
-* Pull Parser Function::    How to call @code{yypull_parse} and what it returns.
-* Parser Create Function::  How to call @code{yypstate_new} and what it returns.
-* Parser Delete Function::  How to call @code{yypstate_delete} and what it returns.
+* Push Parser Interface::   How to create, use, and destroy push parsers.
 * Lexical::                 You must supply a function @code{yylex}
                              which reads tokens.
 * Error Reporting::         Passing error messages to the user.
@@ -7027,16 +7027,40 @@ void yyerror (YYLTYPE *llocp, int *randomness, const char *msg);
 int  yyparse (int *randomness);
@end example

-@node Push Parser Function
-@section The Push Parser Function @code{yypush_parse}
-@findex yypush_parse
+@node Push Parser Interface
+@section Push Parser Interface

-You call the function @code{yypush_parse} to parse a single token.  This
+@findex yypstate_new
+You call the function @code{yypstate_new} to create a new parser instance.
+This function is available if either the @samp{%define api.push-pull push}
+or @samp{%define api.push-pull both} declaration is used.  @xref{Push Decl}.
+
+@deftypefun {yypstate*} yypstate_new (@code{void})
+@anchor{yypstate_new}
+Return a valid parser instance if there is memory available, 0 otherwise.
+In impure mode, it will also return 0 if a parser instance is currently
+allocated.
+@end deftypefun
+
+@findex yypstate_delete
+You call the function @code{yypstate_delete} to delete a parser instance.
 function is available if either the @samp{%define api.push-pull push} or
@samp{%define api.push-pull both} declaration is used.
@xref{Push Decl}.

+@deftypefun void yypstate_delete (@code{yypstate *}@var{yyps})
+@anchor{yypstate_delete}
+Reclaim the memory associated with a parser instance.  After this call, you
+should no longer attempt to use the parser instance.
+@end deftypefun
+
+@findex yypush_parse
+You call the function @code{yypush_parse} to parse a single token.  This
+function is available if either the @samp{%define api.push-pull push} or
+@samp{%define api.push-pull both} declaration is used.  @xref{Push Decl}.
+
@deftypefun int yypush_parse (@code{yypstate *}@var{yyps})
+@anchor{yypush_parse}
 The value returned by @code{yypush_parse} is the same as for @code{yyparse}
 with the following exception: it returns @code{YYPUSH_MORE} if more input is
 required to finish parsing the grammar.
@@ -7050,50 +7074,35 @@ reuse.  For example, a calculator application which parses each input line
 as an expression can just keep reusing the same @code{yyps} even if an input
 was invalid.

-@node Pull Parser Function
-@section The Pull Parser Function @code{yypull_parse}
-@findex yypull_parse
-
 You call the function @code{yypull_parse} to parse the rest of the input
 stream.  This function is available if the @samp{%define api.push-pull both}
-declaration is used.
-@xref{Push Decl}.
+declaration is used.  @xref{Push Decl}.

@deftypefun int yypull_parse (@code{yypstate *}@var{yyps})
+@anchor{yypull_parse}
 The value returned by @code{yypull_parse} is the same as for @code{yyparse}.

 The parser instance @code{yyps} may be reused for new parses.
@end deftypefun

-@node Parser Create Function
-@section The Parser Create Function @code{yystate_new}
-@findex yypstate_new
+@deftypefun int yypstate_expected_tokens (@code{const yypstate *}yyps, @code{yysymbol_kind_t} @var{argv}@code{[]}, @code{int} @var{argc})
+Fill @var{argv} with the expected tokens, which never includes
+@code{YYSYMBOL_YYEMPTY}, @code{YYSYMBOL_YYerror}, or
+@code{YYSYMBOL_YYUNDEF}.

-You call the function @code{yypstate_new} to create a new parser instance.
-This function is available if either the @samp{%define api.push-pull push} or
-@samp{%define api.push-pull both} declaration is used.
-@xref{Push Decl}.
+Never put more than @var{argc} elements into @var{argv}, and on success
+return the number of tokens stored in @var{argv}.  If there are more
+expected tokens than @var{argc}, fill @var{argv} up to @var{argc} and return
+0.  If there are no expected tokens, also return 0, but set @code{argv[0]}
+to @code{YYSYMBOL_YYEMPTY}.

-@deftypefun {yypstate*} yypstate_new (@code{void})
-The function will return a valid parser instance if there was memory available
-or 0 if no memory was available.
-In impure mode, it will also return 0 if a parser instance is currently
-allocated.
+When LAC is enabled, may return a negative number on errors,
+such as @code{YYENOMEM} on memory exhaustion.
+
+If @var{argv} is null, return the size needed to store all the possible
+values, which is always less than @code{YYNTOKENS}.
@end deftypefun

-@node Parser Delete Function
-@section The Parser Delete Function @code{yystate_delete}
-@findex yypstate_delete
-
-You call the function @code{yypstate_delete} to delete a parser instance.
-function is available if either the @samp{%define api.push-pull push} or
-@samp{%define api.push-pull both} declaration is used.
-@xref{Push Decl}.
-
-@deftypefun void yypstate_delete (@code{yypstate *}@var{yyps})
-This function will reclaim the memory associated with a parser instance.
-After this call, you should no longer attempt to use the parser instance.
-@end deftypefun

@node Lexical
@section The Lexical Analyzer Function @code{yylex}
@@ -7115,6 +7124,7 @@ that need it.  @xref{Invocation}.

@menu
 * Calling Convention::  How @code{yyparse} calls @code{yylex}.
+* Special Tokens::      Signaling end-of-file and errors to the parser.
 * Tokens from Literals:: Finding token kinds from string aliases.
 * Token Values::        How @code{yylex} must return the semantic value
                          of the token it has read.
@@ -7168,6 +7178,49 @@ This interface has been designed so that the output from the @code{lex}
 utility can be used without change as the definition of @code{yylex}.


+@node Special Tokens
+@subsection Special Tokens
+
+In addition to the user defined tokens, Bison generates a few special tokens
+that @code{yylex} may return.
+
+The @code{YYEOF} token denotes the end of file, and signals to the parser
+that there is nothing left afterwards.  @xref{Calling Convention}, for an
+example.
+
+Returning @code{YYUNDEF} tells the parser that some lexical error was found.
+It will emit an error message about an ``invalid token'', and enter
+error-recovery (@pxref{Error Recovery}).  Returning an unknown token kind
+results in the exact same behavior.
+
+Returning @code{YYerror} requires the parser to enter error-recovery
+@emph{without} emitting an error message.  This way the lexical analyzer can
+produce an accurate error messages about the invalid input (something the
+parser cannot do), and yet benefit from the error-recovery features of the
+parser.
+
+@example
+int
+yylex (void)
+@{
+  @dots{}
+  switch (c)
+    @{
+      @dots{}
+      case '0': case '1': case '2': case '3': case '4':
+      case '5': case '6': case '7': case '8': case '9':
+        @dots{}
+        return TOK_NUM;
+      @dots{}
+      case EOF:
+        return YYEOF;
+      default:
+        yyerror ("syntax error: invalid character: %c", c);
+        return YYerror;
+    @}
+@}
+@end example
+
@node Tokens from Literals
@subsection Finding Tokens by String Literals

@@ -7471,7 +7524,7 @@ enum yysymbol_kind_t
@{
  YYSYMBOL_YYEMPTY = -2,      /* No symbol.  */
  YYSYMBOL_YYEOF = 0,         /* "end of file"  */
-  YYSYMBOL_YYERROR = 1,       /* error  */
+  YYSYMBOL_YYerror = 1,       /* error  */
  YYSYMBOL_YYUNDEF = 2,       /* "invalid token"  */
  YYSYMBOL_PLUS = 3,          /* "+"  */
  YYSYMBOL_MINUS = 4,         /* "-"  */
@@ -7497,24 +7550,31 @@ The location of the syntax error (that of the unexpected token).

@deftypefun int yypcontext_expected_tokens (@code{const yypcontext_t *}ctx, @code{yysymbol_kind_t} @var{argv}@code{[]}, @code{int} @var{argc})
 Fill @var{argv} with the expected tokens, which never includes
-@code{YYSYMBOL_YYEMPTY}, @code{YYSYMBOL_YYERROR}, or
+@code{YYSYMBOL_YYEMPTY}, @code{YYSYMBOL_YYerror}, or
@code{YYSYMBOL_YYUNDEF}.

 Never put more than @var{argc} elements into @var{argv}, and on success
-return the effective number of tokens stored in @var{argv}.  Return 0 if
-there are more than @var{argc} expected tokens, yet fill @var{argv} up to
-@var{argc}.  When LAC is enabled, may return a negative number on errors,
+return the number of tokens stored in @var{argv}.  If there are more
+expected tokens than @var{argc}, fill @var{argv} up to @var{argc} and return
+0.  If there are no expected tokens, also return 0, but set @code{argv[0]}
+to @code{YYSYMBOL_YYEMPTY}.
+
+When LAC is enabled, may return a negative number on errors,
 such as @code{YYENOMEM} on memory exhaustion.

 If @var{argv} is null, return the size needed to store all the possible
 values, which is always less than @code{YYNTOKENS}.
@end deftypefun

-@deftypefun {const char *} yysymbol_name (@code{symbol_kind_t} @var{symbol})
+@deftypefun {@r{string type}} yysymbol_name (@code{symbol_kind_t} @var{symbol})
 The name of the symbol whose kind is @var{symbol}, possibly translated.
+Depending on the options, may return a @code{const char*} or a
+@code{std::string}.
@end deftypefun

-A custom syntax error function looks as follows.
+A custom syntax error function looks as follows.  This implementation is
+inappropriate for internationalization, see the @file{c/bistromathic}
+example for a better alternative.

@example
 int
@@ -7606,11 +7666,11 @@ recovery.
 In either case, the rest of the action is not executed.
@end deffn

-@deffn {Macro} YYEMPTY
+@deffn {Value} YYEMPTY
 Value stored in @code{yychar} when there is no lookahead token.
@end deffn

-@deffn {Macro} YYEOF
+@deffn {Value} YYEOF
 Value stored in @code{yychar} when the lookahead is the end of the input
 stream.
@end deffn
@@ -7802,7 +7862,7 @@ or @code{detailed}, token aliases can be internationalized:
 %token
    '\n'   _("end of line")
  <double>
-    NUM    _("double precision number")
+    NUM    _("number")
  <symrec*>
    FUN    _("function")
    VAR    _("variable")
@@ -8253,7 +8313,7 @@ the lookahead token has no precedence, then the default is to shift.
@subsection Using Precedence For Non Operators

 Using properly precedence and associativity directives can help fixing
-shift/reduce conflicts that do not involve arithmetics-like operators.  For
+shift/reduce conflicts that do not involve arithmetic-like operators.  For
 instance, the ``dangling @code{else}'' problem (@pxref{Shift/Reduce}) can be
 solved elegantly in two different ways.

@@ -9596,10 +9656,10 @@ and understand the parser run-time traces (@pxref{Tracing}).
@node Understanding
@section Understanding Your Parser

-As documented elsewhere (@pxref{Algorithm})
-Bison parsers are @dfn{shift/reduce automata}.  In some cases (much more
-frequent than one would hope), looking at this automaton is required to
-tune or simply fix a parser.
+As documented elsewhere (@pxref{Algorithm}) Bison parsers are
+@dfn{shift/reduce automata}.  In some cases (much more frequent than one
+would hope), looking at this automaton is required to tune or simply fix a
+parser.

 The textual file is generated when the options @option{--report} or
@option{--verbose} are specified, see @ref{Invocation}.  Its name is made by
@@ -10555,6 +10615,26 @@ For compatibility with POSIX, the standard Bison distribution also contains
 a shell script called @command{yacc} that invokes Bison with the @option{-y}
 option.

+@sp 1
+
+The exit status of @command{bison} is:
+@table @asis
+@item 0 (success)
+when there were no errors.  Warnings, which are diagnostics about dubious
+constructs, do not change the exit status, unless they are turned into
+errors (@pxref{-Werror,,@option{-Werror}}).
+
+@item 1 (failure)
+when there were errors.  No file was generated (except the reports generated
+by @option{--verbose}, etc.).  In particular, the output files that possibly
+existed were not changed.
+
+@item 63 (mistmatch)
+when @command{bison} does not meet the version requirements of the grammar
+file. @xref{Require Decl}.  No file was generated or changed.
+@end table
+
+
@menu
 * Bison Options::     All the options described in detail,
                        in alphabetical order by short options.
@@ -10601,7 +10681,7 @@ Print the version number of Bison and exit.
 Print the name of the directory containing locale-dependent data.

@item --print-datadir
-Print the name of the directory containing skeletons and XSLT.
+Print the name of the directory containing skeletons, CSS and XSLT.

@item -u
@item --update
@@ -10948,6 +11028,7 @@ instance, @option{-Wno-yacc} will hide the warnings about
 POSIX Yacc incompatibilities.

@item -Werror
+@anchor{-Werror}
 Turn enabled warnings for every @var{category} into errors, unless they are
 explicitly disabled by @option{-Wno-error=@var{category}}.

@@ -11545,7 +11626,7 @@ struct token
  @{
    YYEMPTY = -2,              // No token.
    YYEOF = 0,                 // "end of file"
-    YYERRCODE = 256,           // error
+    YYerror = 256,             // error
    YYUNDEF = 257,             // "invalid token"
    PLUS = 258,                // "+"
    MINUS = 259,               // "-"
@@ -12062,9 +12143,10 @@ Fill @var{argv} with the expected tokens, which never includes
@code{symbol_kind::S_YYUNDEF}.

 Never put more than @var{argc} elements into @var{argv}, and on success
-return the effective number of tokens stored in @var{argv}.  Return 0 if
-there are more than @var{argc} expected tokens, yet fill @var{argv} up to
-@var{argc}.
+return the number of tokens stored in @var{argv}.  If there are more
+expected tokens than @var{argc}, fill @var{argv} up to @var{argc} and return
+0.  If there are no expected tokens, also return 0, but set @code{argv[0]}
+to @code{symbol_kind::S_YYEMPTY}.

 If @var{argv} is null, return the size needed to store all the possible
 values, which is always less than @code{YYNTOKENS}.
@@ -12072,9 +12154,13 @@ values, which is always less than @code{YYNTOKENS}.

@deftypemethod {parser} {const char *} symbol_name (@code{symbol_kind_t} @var{symbol}) @code{const}
 The name of the symbol whose kind is @var{symbol}, possibly translated.
+
+Returns a @code{std::string} when @code{parse.error} is @code{verbose}.
@end deftypemethod

-A custom syntax error function looks as follows.
+A custom syntax error function looks as follows.  This implementation is
+inappropriate for internationalization, see the @file{c/bistromathic}
+example for a better alternative.

@example
 void
@@ -12202,6 +12288,12 @@ applicable) location.
 The kind of this symbol.
@end deftypemethod

+@deftypemethod {symbol_type} {const char *} name () @code{const}
+The name of the kind of this symbol.
+
+Returns a @code{std::string} when @code{parse.error} is @code{verbose}.
+@end deftypemethod
+
@sp 1

 For each token kind, Bison generates named constructors as follows.
@@ -12330,7 +12422,7 @@ interactions.  A hand-written scanner is actually easier to interface with.
@node Calc++ --- C++ Calculator
@subsubsection Calc++ --- C++ Calculator

-Of course the grammar is dedicated to arithmetics, a single expression,
+Of course the grammar is dedicated to arithmetic, a single expression,
 possibly preceded by variable assignments.  An environment containing
 possibly predefined variables such as @code{one} and @code{two}, is
 exchanged with the parser.  An example of valid input follows.
@@ -12950,9 +13042,6 @@ of the parser is always local to an instance of the parser class.
 Therefore, all Java parsers are ``pure'', and the @code{%define api.pure}
 directive does nothing when used in Java.

-Push parsers are currently unsupported in Java and @code{%define
-api.push-pull} have no effect.
-
 GLR parsers are currently unsupported in Java.  Do not use the
@code{glr-parser} directive.

@@ -13224,9 +13313,10 @@ Fill @var{argv} with the expected tokens, which never includes
@code{SymbolKind.S_YYERROR}, or @code{SymbolKind.S_YYUNDEF}.

 Never put more than @var{argc} elements into @var{argv}, and on success
-return the effective number of tokens stored in @var{argv}.  Return 0 if
-there are more than @var{argc} expected tokens, yet fill @var{argv} up to
-@var{argc}.
+return the number of tokens stored in @var{argv}.  If there are more
+expected tokens than @var{argc}, fill @var{argv} up to @var{argc} and return
+0.  If there are no expected tokens, also return 0, but set @code{argv[0]}
+to @code{null}.

 If @var{argv} is null, return the size needed to store all the possible
 values, which is always less than @code{YYNTOKENS}.
@@ -13267,9 +13357,9 @@ changed using @code{%define api.location.type @{@var{class-name}@}}.
@end deftypemethod

@deftypemethod {Lexer} {int} yylex ()
-Return the next token.  Its type is the return value, its semantic
-value and location are saved and returned by the their methods in the
-interface.
+Return the next token.  Its type is the return value, its semantic value and
+location are saved and returned by the their methods in the interface.  Not
+needed for push-only parsers.

 Use @samp{%define lex_throws} to specify any uncaught exceptions.
 Default is @code{java.io.IOException}.
@@ -13279,7 +13369,7 @@ Default is @code{java.io.IOException}.
@deftypemethodx {Lexer} {Position} getEndPos ()
 Return respectively the first position of the last token that @code{yylex}
 returned, and the first position beyond it.  These methods are not needed
-unless location tracking is active.
+unless location tracking and pull parsing are active.

 They should return new objects for each call, to avoid that all the symbol
 share the same Position boundaries.
@@ -13289,7 +13379,8 @@ The return type can be changed using @code{%define api.position.type
@end deftypemethod

@deftypemethod {Lexer} {Object} getLVal ()
-Return the semantic value of the last token that yylex returned.
+Return the semantic value of the last token that yylex returned.  Not needed
+for push-only parsers.

 The return type can be changed using @samp{%define api.value.type
@{@var{class-name}@}}.
@@ -13327,6 +13418,10 @@ public void reportSyntaxError(YYParser.Context ctx) @{
  System.err.println("");
@}
@end example
+
+@noindent
+This implementation is inappropriate for internationalization, see the
+@file{c/bistromathic} example for a better alternative.
@end deftypemethod

@node Java Action Features
@@ -14613,6 +14708,14 @@ is given a nonzero value, the parser will output information on input
 symbols and parser action.  @xref{Tracing}.
@end deffn

+@deffn {Value} YYEMPTY
+The pseudo token kind when there is no lookahead token.
+@end deffn
+
+@deffn {Value} YYEOF
+The token kind denoting is the end of the input stream.
+@end deffn
+
@deffn {Macro} yyerrok
 Macro to cause parser to recover immediately to its normal mode
 after a syntax error.  @xref{Error Recovery}.
@@ -14662,8 +14765,8 @@ In semantic actions, it stores the location of the lookahead token.
@end deffn

@deffn {Type} YYLTYPE
-Data type of @code{yylloc}; by default, a structure with four
-members.  @xref{Location Type}.
+Data type of @code{yylloc}.  By default in C, a structure with four members
+(start/end line/column).  @xref{Location Type}.
@end deffn

@deffn {Variable} yylval
@@ -14702,24 +14805,26 @@ Deprecated, use @code{%printer} instead (@pxref{Printer Decl}).
@deffn {Function} yypstate_delete
 The function to delete a parser instance, produced by Bison in push mode;
 call this function to delete the memory associated with a parser.
-@xref{Parser Delete Function}.  Does nothing when called with a null pointer.
+@xref{yypstate_delete,,@code{yypstate_delete}}.  Does nothing when called
+with a null pointer.
@end deffn

@deffn {Function} yypstate_new
 The function to create a parser instance, produced by Bison in push mode;
 call this function to create a new parser.
-@xref{Parser Create Function}.
+@xref{yypstate_new,,@code{yypstate_new}}.
@end deffn

@deffn {Function} yypull_parse
 The parser function produced by Bison in push mode; call this function to
 parse the rest of the input stream.
-@xref{Pull Parser Function}.
+@xref{yypull_parse,,@code{yypull_parse}}.
@end deffn

@deffn {Function} yypush_parse
 The parser function produced by Bison in push mode; call this function to
-parse a single token.  @xref{Push Parser Function}.
+parse a single token.
+@xref{yypush_parse,,@code{yypush_parse}}.
@end deffn

@deffn {Macro} YYRECOVERING
@@ -14767,6 +14872,10 @@ should not be confused with the @emph{symbol kinds}, used internally by the
 parser.
@end deffn

+@deffn {Value} YYUNDEF
+The token kind denoting an unknown token.
+@end deffn
+

@node Glossary
@appendix Glossary
@@ -14853,12 +14962,21 @@ A continuous flow of data between devices or programs.
@item Kind
 ``Token'' and ``symbol'' are each overloaded to mean either a grammar symbol
 (kind) or all parse info (kind, value, location) associated with occurrences
-of that grammar symbol from the input.  To disambiguate, we use ``token
-kind'' and ``symbol kind'' to mean both grammar symbols and the types that
-represent them in a base programming language (C, C++, etc.). However, we
-use ``token'' and ``symbol'' without the word ``kind'' to mean parsed
+of that grammar symbol from the input.  To disambiguate,
+
+@itemize
+@item
+we use ``token kind'' and ``symbol kind'' to mean both grammar symbols and
+the values that represent them in a base programming language (C, C++,
+etc.).  The names of the types of these values are typically
+@code{token_kind_t}, or @code{token_kind_type}, or @code{TokenKind},
+depending on the programming language.
+
+@item
+we use ``token'' and ``symbol'' without the word ``kind'' to mean parsed
 occurrences, and we append the word ``type'' to refer to the types that
 represent them in a base programming language.
+@end itemize

 In summary: When you see ``kind'', interpret ``symbol'' or ``token'' to mean
 a @emph{grammar symbol}.  When you don't see ``kind'' (including when you
@@ -15116,7 +15234,7 @@ London, Department of Computer Science, TR-00-12 (December 2000).
@c LocalWords: redeclare automata Dparse localedir datadir XSLT midrule Wno
@c LocalWords: multitable headitem hh basename Doxygen fno filename gdef de
@c LocalWords: doxygen ival sval deftypemethod deallocate pos deftypemethodx
-@c LocalWords: Ctor defcv defcvx arg accessors arithmetics CPP ifndef CALCXX
+@c LocalWords: Ctor defcv defcvx arg accessors CPP ifndef CALCXX YYerror
@c LocalWords: lexer's calcxx bool LPAREN RPAREN deallocation cerrno climits
@c LocalWords: cstdlib Debian undef yywrap unput noyywrap nounput zA yyleng
@c LocalWords: errno strtol ERANGE str strerror iostream argc argv Javadoc PSLR
@@ -15150,7 +15268,7 @@ London, Department of Computer Science, TR-00-12 (December 2000).
@c LocalWords: Wdangling yytoken erreur syntaxe inattendu attendait nombre
@c LocalWords: YYUNDEF SymbolKind yypcontext YYENOMEM TOKENMAX getBundle
@c LocalWords: ResourceBundle myResources getString getName getToken
-@c LocalWords: getLocation getExpectedTokens reportSyntaxError
+@c LocalWords: getLocation getExpectedTokens reportSyntaxError bistromathic

@c Local Variables:
@c ispell-dictionary: "american"
@@ -131,7 +131,7 @@ dist_man_MANS = $(top_srcdir)/%D%/bison.1
 EXTRA_DIST += $(dist_man_MANS:.1=.x)
 MAINTAINERCLEANFILES += $(dist_man_MANS)

-# Differences to ignore when comparing the man page (the date).
+# Differences to ignore when comparing man pages (the date).
 remove_time_stamp = \
  sed 's/^\(\.TH[^"]*"[^"]*"[^"]*\)"[^"]*"/\1/'

@@ -140,17 +140,31 @@ if ! CROSS_COMPILING
 MAN_DEPS = %D%/bison.help %D%/bison.x $(top_srcdir)/configure
 endif

+# If we don't have help2man, just touch the target.  Maintainers must
+# have the real thing, so if there's a .git directory, fail hard.
+#
+# We shouldn't need this, but on some OS the timestamps in the tarball
+# leave us no choice.  See
+# https://lists.gnu.org/r/bug-bison/2020-05/msg00055.html.
 $(top_srcdir)/%D%/bison.1: $(MAN_DEPS)
-	$(AM_V_GEN)$(HELP2MAN)			\
-	    --include=$(top_srcdir)/%D%/bison.x	\
-	    --output=$@.tmp tests/bison
-	$(AM_V_at)if $(remove_time_stamp) $@ >$@a.tmp 2>/dev/null &&		\
-	   $(remove_time_stamp) $@.tmp | cmp $@a.tmp - >/dev/null 2>&1; then	\
-	  touch $@;								\
-	else									\
-	  mv $@.tmp $@;								\
+	$(AM_V_GEN)if $(HELP2MAN) --version >/dev/null 2>&1; then	\
+	  $(HELP2MAN)							\
+	    --include=$(top_srcdir)/%D%/bison.x				\
+	    --output=$@.tmp tests/bison &&				\
+	  { $(remove_time_stamp) $@     >$@a.tmp || true; } &&		\
+	    $(remove_time_stamp) $@.tmp >$@b.tmp &&			\
+	  if diff $@a.tmp $@b.tmp >/dev/null 2>&1; then			\
+	    touch $@;							\
+	  else								\
+	    mv $@.tmp $@;						\
+	  fi &&								\
+	  rm -f $@*.tmp;						\
+	elif test -d $(srcdir)/.git; then				\
+	  echo >&2 "ERROR: $@: help2man is needed";			\
+	  exit 1;							\
+	else								\
+	  touch $@;							\
 	fi
-	$(AM_V_at)rm -f $@*.tmp

 if ENABLE_YACC
 nodist_man_MANS = %D%/yacc.1
@@ -252,7 +252,6 @@ sub generate_grammar_triangular ($$@)
  my $out = new IO::File ">$base.y"
    or die;
  print $out <<EOF;
-%define parse.error detailed
 %{
 #include <stdio.h>
 #include <stdlib.h>
@@ -388,7 +387,6 @@ sub generate_grammar_calc ($$@)
 %}

 %define api.value.type union
-%define parse.error detailed
 $directives

 %{
@@ -812,7 +810,8 @@ sub compile ($)
  my ($base) = @_;
  my $compiler = compiler ($base);

-  my $my_bison = `sed -ne '/%bison "\\(.*\\)"/{s//\\1/;p;q;}' $base.y`;
+  my $my_bison = `sed -ne '/[/][/] %bison "\\(.*\\)"/{s//\\1/;p;q;}' $base.y`;
+  chop $my_bison;
  run ((length $my_bison ? $my_bison : $bison) . " $base.y -o $base.c");
  if ($gbench)
    {
@@ -902,8 +901,13 @@ directive list.
 sub bench_with_gbenchmark ($@)
 {
  my ($grammar, @directive) = @_;
+  my $compiler = compiler ("y0");

  my $readme = new IO::File ">README.md";
+  print $readme <<EOF;
+compiler: $compiler $cflags
+EOF
+
  my @obj = ();
  for my $i (0 .. $#directive)
    {
@@ -923,7 +927,6 @@ sub bench_with_gbenchmark ($@)
 BENCHMARK_MAIN();
 EOF

-  my $compiler = compiler ("y0");
  run "$compiler -o main $cflags main.c @obj -lbenchmark";
  run "./main | tee -a README.md";
 }
@@ -1121,7 +1124,7 @@ sub parse_dir ()
  elsif ($token[0] eq '%b')
    {
      shift @token;
-      @res = ("/*\n%bison \"$token[0]\"\\\n*/");
+      @res = ("// %bison \"$token[0]\"");
    }
  else
    {
@@ -1160,19 +1163,26 @@ sub getopt ()

 getopt;

+my $basedir = 'benches';
+
 # Create the directory we work in.
-mkdir "benches" or die "cannot create benches"
-  unless -d "benches";
-my $count = 1;
-++$count
-  while -d "benches/$count";
-my $dir = "benches/$count";
+mkdir $basedir or die "cannot create directory $basedir"
+  unless -d $basedir;
+
+my $count = 0;
+my $dir;
+while (!$dir || -d $dir)
+{
+  ++$count;
+  $dir = sprintf "%s/%03d", $basedir, $count;
+}
 mkdir $dir
-  or die "cannot create $dir";
-unlink "benches/latest"
-  or die "cannot unlink benches/latest"
-  if -l "benches/latest";
-symlink $count, "benches/latest"
+  or die "cannot create directory $dir";
+
+unlink "$basedir/latest"
+  or die "cannot unlink $basedir/latest"
+  if -l "$basedir/latest";
+symlink sprintf("%03d", $count), "$basedir/latest"
  or die "cannot create symlink";
 chdir $dir
  or die "cannot chdir $dir";
@@ -13,8 +13,8 @@ semantic value.

 Run as `./simple`.

-Extracted from the documentation: "A Simple C++ Example".
-https://www.gnu.org/software/bison/manual/html_node/A-Simple-C_002b_002b-Example.html
+Extracted from the documentation: [A Simple C++
+Example](https://www.gnu.org/software/bison/manual/html_node/A-Simple-C_002b_002b-Example.html).

 ## variant.yy - Self-contained example in C++98
 A variation of simple.yy, in C++98.
@@ -36,8 +36,8 @@ starting point for a clean parser in C++.  The previous examples are better
 introductory examples, and the C examples are also useful introductory
 examples.

-Extracted from the documentation: "A Complete C++ Example".
-https://www.gnu.org/software/bison/manual/html_node/A-Complete-C_002b_002b-Example.html
+Extracted from the documentation: [A Complete C++
+Example](https://www.gnu.org/software/bison/manual/html_node/A-Complete-C_002b_002b-Example.html).

 <!---

@@ -5,9 +5,9 @@ saw the traditional implementation in C, please first read
 examples/c/lexcalc, which can be seen as a C precursor of this example.

 Read the corresponding chapter in the documentation: "A Complete C++
-Example".  It is also available on line (maybe with a different version of
-Bison):
-https://www.gnu.org/software/bison/manual/html_node/A-Complete-C_002b_002b-Example.html
+Example".  It is also available [on
+line](https://www.gnu.org/software/bison/manual/html_node/A-Complete-C_002b_002b-Example.html)
+(maybe with a different version of Bison).

 To use it, copy this directory into some work directory, and run `make` to
 compile the executable, and try it.  It is a simple calculator which accepts
@@ -139,7 +139,7 @@ namespace yy
 int
 main (int argc, const char *argv[])
 {
-  if (2 <= argc && isdigit (*argv[1]))
+  if (2 <= argc && isdigit (static_cast<unsigned char> (*argv[1])))
    {
      auto maxl = strtol (argv[1], nullptr, 10);
      max = INT_MIN <= maxl && maxl <= INT_MAX ? int(maxl) : 4;
@@ -10,8 +10,8 @@ The first example is that of a simple double-precision Reverse Polish
 Notation calculator (a calculator using postfix operators). This example
 provides a good starting point, since operator precedence is not an issue.

-Extracted from the documentation: "Reverse Polish Notation Calculator"
-https://www.gnu.org/software/bison/manual/html_node/RPN-Calc.html
+Extracted from the documentation: [Reverse Polish Notation
+Calculator](https://www.gnu.org/software/bison/manual/html_node/RPN-Calc.html).

 ## calc - Simple Calculator
 This example is slightly more complex than rpcalc: it features infix
@@ -24,18 +24,18 @@ A more complete C example: a multi-function calculator.  More complex than
 the previous example.  Using precedence directives to support infix
 operators.

-Extracted from the documentation: "Multi-Function Calculator: mfcalc".
-https://www.gnu.org/software/bison/manual/html_node/Multi_002dfunction-Calc.html
+Extracted from the documentation: [Multi-Function Calculator:
+mfcalc](https://www.gnu.org/software/bison/manual/html_node/Multi_002dfunction-Calc.html).

 ## lexcalc - calculator with Flex and Bison
 The calculator with precedence directives and location tracking.  It uses
 Flex to generate the scanner.

 ## reccalc - recursive calculator with Flex and Bison
-The example builds on top of the previous one to provide a reentrant parser.
-Such parsers can be called concurrently in different threads, or even
-recursively.  To demonstrate this feature, expressions in parentheses are
-tokenized as strings, and then recursively parsed from the parser.  So
+This example builds on top of the previous one to provide a reentrant
+parser.  Such parsers can be called concurrently in different threads, or
+even recursively.  To demonstrate this feature, expressions in parentheses
+are tokenized as strings, and then recursively parsed from the parser.  So
 `(((1)+(2))*((3)+(4)))` uses eight parsers, with a depth of four.

 ## pushcalc - calculator implemented with a push parser
@@ -53,10 +53,13 @@ push-parser model.
 This example demonstrates best practices when using Bison.
 - Its hand-written scanner tracks locations.
 - Its interface is pure.
+- It uses the `error` token to get error recovery.
 - Its interface is "incremental", well suited for interaction: it uses the
  push-parser API to feed the parser with the incoming tokens.
 - It features an interactive command line with completion based on the
  parser state, based on `yyexpected_tokens`.
+- It uses Bison's standard catalogue for internationalization of generated
+  messages.
 - It uses a custom syntax error with location, lookahead correction and
  token internationalization.
 - It supports debug traces with semantic values.
@@ -3,20 +3,26 @@

 BASE = bistromathic
 BISON = bison
-FLEX = flex
 XSLTPROC = xsltproc

+# We need to find the headers and libs for readline (and possibly intl).
+# You probably need to customize this for your own environment.
+CPPFLAGS = -I/opt/local/include
+LDFLAGS = -L/opt/local/lib
+
+# Find the translation catalogue for Bison's generated messagess.
+BISON_LOCALEDIR = $(shell $(BISON) $(BISON_FLAGS) --print-localedir)
+CPPFLAGS += -DENABLE_NLS -DBISON_LOCALEDIR='"$(BISON_LOCALEDIR)"'
+
+LIBS = -lreadline -lm # In some environments, -lintl is needed.
+
 all: $(BASE)

 %.c %.h %.xml %.gv: %.y
 	$(BISON) $(BISONFLAGS) --defines --xml --graph=$*.gv -o $*.c $<

-%.c: %.l
-	$(FLEX) $(FLEXFLAGS) -o$*.c $<
-
-scan.o: parse.h
-$(BASE): parse.o scan.o
-	$(CC) $(CFLAGS) -o $@ $^
+$(BASE): parse.o
+	$(CC) $(CPPFLAGS) $(CFLAGS) -o $@ $^ $(LDFLAGS) $(LIBS)

 run: $(BASE)
 	@echo "Type bistromathic expressions.  Quit with ctrl-d."
@@ -28,8 +34,7 @@ html: $(BASE).html

 CLEANFILES =						\
  $(BASE) *.o						\
-  parse.[ch] parse.output parse.xml parse.html parse.gv	\
-  scan.c
+  parse.[ch] parse.output parse.xml parse.html parse.gv

 clean:
 	rm -f $(CLEANFILES)
@@ -2,15 +2,21 @@
 This example demonstrates best practices when using Bison.
 - Its hand-written scanner tracks locations.
 - Its interface is pure.
+- It uses the `error` token to get error recovery.
 - Its interface is "incremental", well suited for interaction: it uses the
  push-parser API to feed the parser with the incoming tokens.
 - It features an interactive command line with completion based on the
  parser state, based on `yyexpected_tokens`.
+- It uses Bison's standard catalogue for internationalization of generated
+  messages.
 - It uses a custom syntax error with location, lookahead correction and
  token internationalization.
 - It supports debug traces with semantic values.
 - It uses named references instead of the traditional $1, $2, etc.

+To customize the interaction with bistromathic, see the GNU Readline user
+manual (see `info rluserman`).
+
 <!---
 Local Variables:
 fill-column: 76
@@ -15,12 +15,47 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.

-# macOS' version of readline does not repeat stdin on stdout in
-# non-interactive mode.
-if ! echo '1-1' | prog | grep '1-1'; then
-   strip_prompt=true
+# Users may customize the behavior of readline, which might break our
+# expected results.
+INPUTRC=/dev/null
+export INPUTRC
+
+# Beware of portability issues of readline when not feeding it from a
+# terminal.
+#
+# With recent versions of GNU Readline, input "1+2*3\n" gives
+# "> 1+2*3\n7\n> \n"
+#
+# macOS' version does not display the prompt and does not repeat stdin
+# on stdout, so input "1+2*3\n" gives "7\n" as output.  Let's try to
+# cope with this.
+#
+# On OpenBSD 6.5 the prompt is displayed, but the input is not
+# repeated (!).  So input "1+2*3\n" gives "> 7\n> \n" as output.
+#
+# On AIX, you get some escaping sequence before the prompt:
+# "<ESC>[?1034h> 1+2*3".  It appears to pass the terminfo capability
+# "smm", to put the terminal in "meta mode": as if the user had hit
+# META.
+
+echo >perfect '> 0
+0
+> '
+
+echo >ok '0'
+echo '0' | prog >effective
+
+echo "checking for readline output"
+if diff perfect effective; then
+    # Alles ist gut.
+    strip_prompt=false
+elif diff ok effective; then
+    strip_prompt=true
+else
+    skip "this is not the GNU Readline we expect"
 fi

+
 cat >input <<EOF
 1+2*3
 EOF
@@ -65,26 +100,159 @@ cat >input <<EOF
 *
 EOF
 run 0 '> *
-> err: 1.1: syntax error: expected end of file or - or ( or exit or double precision number or function or variable before *'
+> ''
+err: 1.1: syntax error: expected end of file or - or ( or exit or number or function etc., before *'

 cat >input <<EOF
 1 + 2 * * 3
 EOF
 run 0 '> 1 + 2 * * 3
-> err: 1.9: syntax error: expected - or ( or double precision number or function or variable before *'
-
-cat >input <<EOF
-100%
-EOF
-run 0 '> 100%
-100
-> err: 1.4: error: invalid character'
+> ''
+err: 1.9: syntax error: expected - or ( or number or function or variable before *'

 cat >input <<EOF
 1 / 0
 EOF
 run 0 '> 1 / 0
-> err: 1.1-5: error: division by zero'
+> ''
+err: 1.1-5: error: division by zero'
+
+
+## ---------------- ##
+## Error recovery.  ##
+## ---------------- ##
+
+cat >input <<EOF
+((1 ++ 2) ** 3)
+(1 ++ 2) + (3 ** 4)
+EOF
+run 0 '> ((1 ++ 2) ** 3)
+666
+> (1 ++ 2) + (3 ** 4)
+1332
+> ''
+err: 1.6: syntax error: expected - or ( or number or function or variable before +
+err: 2.5: syntax error: expected - or ( or number or function or variable before +
+err: 2.16: syntax error: expected - or ( or number or function or variable before *'
+
+# The rule "( error )" should work even if there are no tokens between "(" and ")".
+cat >input <<EOF
+()
+EOF
+run 0 '> ()
+666
+> ''
+err: 1.2: syntax error: expected - or ( or number or function or variable before )'
+
+
+cat >input <<EOF
+100% + 10
+EOF
+run 0 '> 100% + 10
+> ''
+err: 1.4: syntax error: invalid character: %'
+
+# Traces.  This allows to check the location of the error.  If we
+# forget to map YYerror to YYUNDEF, error recovery enters an endless
+# loop with this input.
+cat >input <<EOF
+(+_)
+EOF
+run 0 '> (+_)
+666
+> ''
+err: Starting parse
+err: Entering state 0
+err: Stack now 0
+err: Reading a token
+err: Next token is token ( (1.1: )
+err: Shifting token ( (1.1: )
+err: Entering state 2
+err: Stack now 0 2
+err: Return for a new token:
+err: Reading a token
+err: Next token is token + (1.2: )
+err: LAC: initial context established for +
+err: LAC: checking lookahead +: Err
+err: LAC: checking lookahead end of file: Err
+err: LAC: checking lookahead +: Err
+err: LAC: checking lookahead -: S1
+err: LAC: checking lookahead *: Err
+err: LAC: checking lookahead /: Err
+err: LAC: checking lookahead ^: Err
+err: LAC: checking lookahead (: S2
+err: LAC: checking lookahead ): Err
+err: LAC: checking lookahead =: Err
+err: LAC: checking lookahead exit: Err
+err: LAC: checking lookahead number: S4
+err: LAC: checking lookahead function: S5
+err: LAC: checking lookahead variable: S6
+err: LAC: checking lookahead NEG: Err
+err: 1.2: syntax error: expected - or ( or number or function or variable before +
+err: LAC: initial context discarded due to error recovery
+err: Shifting token error (1.2: )
+err: Entering state 10
+err: Stack now 0 2 10
+err: Next token is token + (1.2: )
+err: LAC: initial context established for +
+err: LAC: checking lookahead +: Err
+err: Error: discarding token + (1.2: )
+err: Error: popping token error (1.2: )
+err: Stack now 0 2
+err: LAC: initial context discarded due to error recovery
+err: Shifting token error (1.2: )
+err: Entering state 10
+err: Stack now 0 2 10
+err: Return for a new token:
+err: 1.3: syntax error: invalid character: _
+err: Reading a token
+err: Error: popping token error (1.2: )
+err: Stack now 0 2
+err: Shifting token error (1.2-3: )
+err: Entering state 10
+err: Stack now 0 2 10
+err: Next token is token invalid token (1.3: )
+err: LAC: initial context established for invalid token
+err: LAC: checking lookahead invalid token: Always Err
+err: Error: discarding token invalid token (1.3: )
+err: Error: popping token error (1.2-3: )
+err: Stack now 0 2
+err: LAC: initial context discarded due to error recovery
+err: Shifting token error (1.2-3: )
+err: Entering state 10
+err: Stack now 0 2 10
+err: Return for a new token:
+err: Reading a token
+err: Next token is token ) (1.4: )
+err: Shifting token ) (1.4: )
+err: Entering state 20
+err: Stack now 0 2 10 20
+err: Reducing stack by rule 15 (line 151):
+err:    $1 = token ( (1.1: )
+err:    $2 = token error (1.2-3: )
+err:    $3 = token ) (1.4: )
+err: -> $$ = nterm exp (1.1-4: 666)
+err: Entering state 7
+err: Stack now 0 7
+err: Return for a new token:
+err: Reading a token
+err: Now at end of input.
+err: LAC: initial context established for end of file
+err: LAC: checking lookahead end of file: R2 G8 S19
+err: Reducing stack by rule 2 (line 126):
+err:    $1 = nterm exp (1.1-4: 666)
+err: -> $$ = nterm input (1.1-4: )
+err: Entering state 8
+err: Stack now 0 8
+err: Now at end of input.
+err: Shifting token end of file (1.5: )
+err: LAC: initial context discarded due to shift
+err: Entering state 19
+err: Stack now 0 8 19
+err: Stack now 0 8 19
+err: Cleanup: popping token end of file (1.5: )
+err: Cleanup: popping nterm input (1.1-4: )' -p
+


 ## ------------ ##
@@ -94,38 +262,47 @@ run 0 '> 1 / 0
 # From now on, the differences between versions of GNU Readline are
 # too painful to try to cope with.
 if $strip_prompt; then
-    echo "SKIP: this is not the GNU Readline we expect"
-    if $exit; then
-        exit 0
-    else
-        exit 1
-    fi
+  echo "SKIP: this is not the GNU Readline we expect"
+  exit $status
 fi

+# On Windows10/MSYS2 the ^G coming from <tab> completion is not
+# emitted the same way
+# (https://lists.gnu.org/r/bug-bison/2020-05/msg00076.html).
+echo "checking for kernel name"
+case `uname -s` in
+  (MSYS*)
+    echo "SKIP: this is Windows/MSYS"
+    exit $status
+    ;;
+esac
+
+
 # Check completion after an operator.
 sed -e 's/\\t/	/g' >input <<EOF
 (1+\t\t
 EOF
 run 0 '> (1+
-(                        cos                      ln
-                        double precision number  sin
-atan                     exp                      sqrt
+(       -       atan    cos     exp     ln      number  sin     sqrt
 > (1+
-> err: 1.4: syntax error: expected - or ( or double precision number or function or variable before end of file'
+> ''
+err: 1.4: syntax error: expected - or ( or number or function or variable before end of file'

 # Check the completion of a word.
 sed -e 's/\\t/	/g' >input <<EOF
 (at\t\t
 EOF
 run 0 '> (atan ( ''
-> err: 1.9: syntax error: expected - or ( or double precision number or function or variable before end of file'
+> ''
+err: 1.9: syntax error: expected - or ( or number or function or variable before end of file'

 # Check the completion at the very beginning.
 sed -e 's/\\t/	/g' >input <<EOF
 e\t\t
 EOF
-run 0 '> e
+run -n 0 '> e
 end of file  exit         exp          ''
 > e
 0
-> err: '
+> ''
+err: '
@@ -19,16 +19,22 @@ bistromathicdir = $(docdir)/%D%
 ## Bistromathics.  ##
 ## --------------- ##

-check_PROGRAMS += %D%/bistromathic
-TESTS += %D%/bistromathic.test
-EXTRA_DIST += %D%/bistromathic.test
-nodist_%C%_bistromathic_SOURCES = %D%/parse.y %D%/parse.h
 %D%/parse.c: $(dependencies)

-# Don't use gnulib's system headers.
-%C%_bistromathic_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
-%C%_bistromathic_LDADD = -lm -lreadline
+if ENABLE_BISTROMATHIC
+  check_PROGRAMS += %D%/bistromathic
+  TESTS += %D%/bistromathic.test
+  nodist_%C%_bistromathic_SOURCES = %D%/parse.y

+  # Don't use gnulib's system headers.
+  %C%_bistromathic_CPPFLAGS =			\
+    -DBISON_LOCALEDIR='"$(localdir)"'		\
+    -DLOCALEDIR='"$(localdir)"'			\
+    -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+  %C%_bistromathic_LDADD = -lm $(LIBREADLINE) $(LIBINTL)
+endif
+
+EXTRA_DIST += %D%/bistromathic.test
 dist_bistromathic_DATA = %D%/parse.y %D%/Makefile %D%/README.md
 CLEANFILES += %D%/parse.[ch] %D%/parse.output
 CLEANDIRS += %D%/*.dSYM
@@ -1,15 +1,28 @@
 %require "3.6"

 %code top {
+  #include <assert.h>
  #include <ctype.h>  // isdigit
+  #include <locale.h> // LC_ALL
  #include <math.h>   // cos, sin, etc.
-  #include <stddef.h> // ptrdiff_t
+  #include <stdarg.h> // va_start
  #include <stdio.h>  // printf
-  #include <stdlib.h> // calloc.
+  #include <stdlib.h> // calloc
  #include <string.h> // strcmp

  #include <readline/readline.h>
  #include <readline/history.h>
+
+  #if defined ENABLE_NLS && ENABLE_NLS
+  // Unable the translation of Bison's generated messages.
+  # define YYENABLE_NLS 1
+  # include <libintl.h>
+  // Unless specified otherwise, we expect bistromathic's own
+  // catalogue to be installed in the same tree as Bison's catalogue.
+  # ifndef LOCALEDIR
+  #  define LOCALEDIR BISON_LOCALEDIR
+  # endif
+  #endif
 }

 %code requires {
@@ -35,13 +48,22 @@
 }

 %code provides {
+# ifndef __attribute__
+#  ifndef __GNUC__
+#   define __attribute__(Spec) /* empty */
+#  endif
+# endif
  int yylex (const char **line, YYSTYPE *yylval, YYLTYPE *yylloc);
-  void yyerror (YYLTYPE *yylloc, char const *msg);
+  void yyerror (YYLTYPE *loc, char const *format, ...)
+    __attribute__ ((__format__ (__printf__, 2, 3)));
 }

 %code {
-#define N_
-#define _
+  #if defined ENABLE_NLS && ENABLE_NLS
+  # define _(Msgid)  gettext (Msgid)
+  #else
+  # define _(Msgid)  (Msgid)
+  #endif

  // Whether to quit.
  int done = 0;
@@ -82,7 +104,7 @@
    EQUAL  "="
    EXIT   "exit"
  <double>
-    NUM _("double precision number")
+    NUM _("number")
  <symrec*>
    FUN _("function")
    VAR _("variable")
@@ -133,6 +155,7 @@ exp:
 | "-" exp  %prec NEG { $$ = -$2; }
 | exp[l] "^" exp[r]  { $$ = pow ($l, $r); }
 | "(" exp ")"        { $$ = $2; }
+| "(" error ")"      { $$ = 666; }
 ;

 // End of grammar.
@@ -235,6 +258,8 @@ yylex (const char **line, YYSTYPE *yylval, YYLTYPE *yylloc)
    case '(': return TOK_LPAREN;
    case ')': return TOK_RPAREN;

+    case '!': return TOK_YYUNDEF;
+
    case '\0': return TOK_YYEOF;

      // Numbers.
@@ -244,9 +269,9 @@ yylex (const char **line, YYSTYPE *yylval, YYLTYPE *yylloc)
      {
        int nchars = 0;
        sscanf (*line - 1, "%lf%n", &yylval->TOK_NUM, &nchars);
-          *line += nchars - 1;
-          yylloc->last_column += nchars - 1;
-          return TOK_NUM;
+        *line += nchars - 1;
+        yylloc->last_column += nchars - 1;
+        return TOK_NUM;
      }

      // Identifiers.
@@ -276,8 +301,8 @@ yylex (const char **line, YYSTYPE *yylval, YYLTYPE *yylloc)

      // Stray characters.
    default:
-      yyerror (yylloc, "error: invalid character");
-      return yylex (line, yylval, yylloc);
+      yyerror (yylloc, "syntax error: invalid character: %c", c);
+      return TOK_YYerror;
    }
 }

@@ -286,40 +311,105 @@ yylex (const char **line, YYSTYPE *yylval, YYLTYPE *yylloc)
 | Parser.  |
 `---------*/

+
+const char *
+error_format_string (int argc)
+{
+  switch (argc)
+    {
+    default: // Avoid compiler warnings.
+    case 0: return _("%@: syntax error");
+    case 1: return _("%@: syntax error: unexpected %u");
+      // TRANSLATORS: '%@' is a location in a file, '%u' is an
+      // "unexpected token", and '%0e', '%1e'... are expected tokens
+      // at this point.
+      //
+      // For instance on the expression "1 + * 2", you'd get
+      //
+      // 1.5: syntax error: expected - or ( or number or function or variable before *
+    case 2: return _("%@: syntax error: expected %0e before %u");
+    case 3: return _("%@: syntax error: expected %0e or %1e before %u");
+    case 4: return _("%@: syntax error: expected %0e or %1e or %2e before %u");
+    case 5: return _("%@: syntax error: expected %0e or %1e or %2e or %3e before %u");
+    case 6: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e before %u");
+    case 7: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e or %5e before %u");
+    case 8: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e or %5e etc., before %u");
+    }
+}
+
+
 int
 yyreport_syntax_error (const yypcontext_t *ctx)
 {
-  int res = 0;
-  YY_LOCATION_PRINT (stderr, *yypcontext_location (ctx));
-  fprintf (stderr, ": syntax error");
-  // Report the tokens expected at this point.
-  {
-    enum { TOKENMAX = 10 };
-    yysymbol_kind_t expected[TOKENMAX];
-    int n = yypcontext_expected_tokens (ctx, expected, TOKENMAX);
-    if (n < 0)
-      // Forward errors to yyparse.
-      res = n;
+  enum { ARGS_MAX = 6 };
+  yysymbol_kind_t arg[ARGS_MAX];
+  int argsize = yypcontext_expected_tokens (ctx, arg, ARGS_MAX);
+  if (argsize < 0)
+    return argsize;
+  const int too_many_expected_tokens = argsize == 0 && arg[0] != YYSYMBOL_YYEMPTY;
+  if (too_many_expected_tokens)
+    argsize = ARGS_MAX;
+  const char *format = error_format_string (1 + argsize + too_many_expected_tokens);
+
+  while (*format)
+    // %@: location.
+    if (format[0] == '%' && format[1] == '@')
+      {
+        YY_LOCATION_PRINT (stderr, *yypcontext_location (ctx));
+        format += 2;
+      }
+    // %u: unexpected token.
+    else if (format[0] == '%' && format[1] == 'u')
+      {
+        fputs (yysymbol_name (yypcontext_token (ctx)), stderr);
+        format += 2;
+      }
+    // %0e, %1e...: expected token.
+    else if (format[0] == '%'
+             && isdigit ((unsigned char) format[1])
+             && format[2] == 'e'
+             && (format[1] - '0') < argsize)
+      {
+        int i = format[1] - '0';
+        fputs (yysymbol_name (arg[i]), stderr);
+        format += 3;
+      }
    else
-      for (int i = 0; i < n; ++i)
-        fprintf (stderr, "%s %s",
-                 i == 0 ? ": expected" : " or", yysymbol_name (expected[i]));
-  }
-  // Report the unexpected token.
-  {
-    yysymbol_kind_t lookahead = yypcontext_token (ctx);
-    if (lookahead != YYSYMBOL_YYEMPTY)
-      fprintf (stderr, " before %s", yysymbol_name (lookahead));
-  }
-  fprintf (stderr, "\n");
-  return res;
+      {
+        fputc (*format, stderr);
+        ++format;
+      }
+  fputc ('\n', stderr);
+  return 0;
 }

+
 // Called by yyparse on error.
-void yyerror (YYLTYPE *loc, char const *msg)
+void yyerror (YYLTYPE *loc, char const *format, ...)
 {
  YY_LOCATION_PRINT (stderr, *loc);
-  fprintf (stderr, ": %s\n", msg);
+  fputs (": ", stderr);
+  va_list args;
+  va_start (args, format);
+  vfprintf (stderr, format, args);
+  va_end (args);
+  putc ('\n', stderr);
+}
+
+
+// Return a newly allocated copy of at most N bytes of STRING.  In
+// other words, return a copy of the initial segment of length N of
+// STRING.
+static char *
+xstrndup (const char *string, size_t n)
+{
+  // len = strnlen (string, n), portably.
+  const char *end = memchr (string, '\0', n);
+  size_t len = end ? (size_t) (end - string) : n;
+  char *new = malloc (len + 1);
+  assert (new);
+  new[len] = '\0';
+  return memcpy (new, string, len);
 }


@@ -368,11 +458,11 @@ expected_tokens (const char *input,
  return res;
 }

-/* Attempt to complete on the contents of TEXT.  START and END bound the
-   region of rl_line_buffer that contains the word to complete.  TEXT is
-   the word to complete.  We can use the entire contents of rl_line_buffer
-   in case we want to do some simple parsing.  Return the array of matches,
-   or NULL if there aren't any. */
+// Attempt to complete on the contents of TEXT.  START and END bound
+// the region of rl_line_buffer that contains the word to complete.
+// TEXT is the word to complete.  We can use the entire contents of
+// rl_line_buffer in case we want to do some simple parsing.  Return
+// the array of matches, or NULL if there aren't any.
 char **
 completion (const char *text, int start, int end)
 {
@@ -383,7 +473,7 @@ completion (const char *text, int start, int end)

  // Get list of token numbers.
  int tokens[YYNTOKENS];
-  char *line = strndup (rl_line_buffer, start);
+  char *line = xstrndup (rl_line_buffer, start);
  int ntokens = expected_tokens (line, tokens, YYNTOKENS);
  free (line);

@@ -425,7 +515,7 @@ completion (const char *text, int start, int end)
        for (int j = 0; j < lcplen; ++j)
          if (matches[1][j] != matches[i][j])
            lcplen = j;
-      matches[0] = strndup (matches[1], lcplen);
+      matches[0] = xstrndup (matches[1], lcplen);
    }

  if (yydebug)
@@ -467,8 +557,20 @@ void init_readline (void)

 int main (int argc, char const* argv[])
 {
+#if defined ENABLE_NLS && ENABLE_NLS
+  // Set up internationalization.
+  setlocale (LC_ALL, "");
+  // Use Bison's standard translation catalogue for error messages
+  // (the generated messages).
+  bindtextdomain ("bison-runtime", BISON_LOCALEDIR);
+  // The translation catalogue of bistromathic is actually included in
+  // Bison's.  In your own project, use the name of your project.
+  bindtextdomain ("bison", LOCALEDIR);
+  textdomain ("bison");
+#endif
+
  // Enable parse traces on option -p.
-  if (argc == 2 && strcmp (argv[1], "-p") == 0)
+  if (1 < argc && strcmp (argv[1], "-p") == 0)
    yydebug = 1;
  init_table ();
  init_readline ();
@@ -477,7 +579,11 @@ int main (int argc, char const* argv[])
    {
      char *line = readline ("> ");
      if (!line)
-        return 0;
+        {
+          // Finish the line started by the prompt.
+          putchar ('\n');
+          break;
+        }
      if (*line)
        add_history (line);
      process_line (&lloc, line);
@@ -12,7 +12,7 @@ all: $(BASE)
 	$(BISON) $(BISONFLAGS) --defines --xml --graph=$*.gv -o $*.c $<

 %.c %.h: %.l
-	$(FLEX) $(FLEXFLAGS) -o$*.c --header-file=$*.h $<
+	$(FLEX) $(FLEXFLAGS) -o$*.c --header=$*.h $<

 scan.o: parse.h
 parse.o: scan.h
@@ -69,7 +69,9 @@ DASH = -
 	$(AM_V_LEX)rm -f $@ $@.tmp
 	$(AM_V_at)$(MKDIR_P) %D%
 	$(AM_V_at)touch $@.tmp
-	$(AM_V_at)$(LEX) $(AM_LFLAGS) $(LFLAGS) -o%D%/scan.c --header-file=%D%/scan.h $(srcdir)/%D%/scan.l
+## --header introduced in 2.5.6, renamed as --header-file in 2.6.4.
+## Backward compatibility ensured since --header is an unambiguous prefix.
+	$(AM_V_at)$(LEX) $(AM_LFLAGS) $(LFLAGS) -o%D%/scan.c --header=%D%/scan.h $(srcdir)/%D%/scan.l
 	$(AM_V_at)mv $@.tmp $@


@@ -15,7 +15,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.

-seq 0 >/dev/null || exit 77
+(seq 0) >/dev/null 2>&1 || skip "gimme one seq"

 cat >input <<EOF
 1+2*3
@@ -9,7 +9,7 @@ afterwards.
 The usual calculator, a very simple version.

 ## calc/Calc.y
-The calculator, but with location tracking and debug traces.
+The calculator, but with location tracking, debug traces, and a push parser.

 <!---

@@ -2,6 +2,7 @@

 %define api.parser.class {Calc}
 %define api.parser.public
+%define api.push-pull push

 %define parse.error custom
 %define parse.trace
@@ -20,12 +21,19 @@

 %code {
  public static void main(String[] args) throws IOException {
-    CalcLexer l = new CalcLexer(System.in);
-    Calc p = new Calc(l);
+    CalcLexer scanner = new CalcLexer(System.in);
+    Calc parser = new Calc(scanner);
    for (String arg : args)
      if (arg.equals("-p"))
-        p.setDebugLevel(1);
-    if (!p.parse())
+        parser.setDebugLevel(1);
+    int status;
+    do {
+      int token = scanner.getToken();
+      Object lval = scanner.getValue();
+      Calc.Location yyloc = scanner.getLocation();
+      status = parser.push_parse(token, lval, yyloc);
+    } while (status == Calc.YYPUSH_MORE);
+    if (status != Calc.YYACCEPT)
      System.exit(1);
  }

@@ -105,14 +113,17 @@ class CalcLexer implements Calc.Lexer {
  Position start = new Position(1, 0);
  Position end = new Position(1, 0);

-  public Position getStartPos() {
-    return new Position(start);
-  }
-
-  public Position getEndPos() {
-    return new Position(end);
+  /**
+   * The location of the last token read.
+   * Implemented with getStartPos and getEndPos in pull parsers.
+   */
+  public Calc.Location getLocation() {
+    return new Calc.Location(new Position(start), new Position(end));
  }

+  /**
+   * Build and emit a syntax error message.
+   */
  public void reportSyntaxError(Calc.Context ctx) {
    System.err.print(ctx.getLocation() + ": syntax error");
    {
@@ -131,26 +142,39 @@ class CalcLexer implements Calc.Lexer {
    System.err.println("");
  }

-  public void yyerror(Calc.Location l, String s) {
-    if (l == null)
-      System.err.println(s);
+  /**
+   * Emit an error referring to the given location in a user-defined way.
+   *
+   * @@param loc The location of the element to which the
+   *                error message is related.
+   * @@param msg The string for the error message.
+   */
+  public void yyerror(Calc.Location loc, String msg) {
+    if (loc == null)
+      System.err.println(msg);
    else
-      System.err.println(l + ": " + s);
+      System.err.println(loc + ": " + msg);
  }

  Integer yylval;

-  public Object getLVal() {
+  /**
+   * The value of the last token read.  Called getLVal in pull parsers.
+   */
+  public Object getValue() {
    return yylval;
  }

-  public int yylex() throws IOException {
+  /**
+   * Fetch the next token.  Called yylex in pull parsers.
+   */
+  public int getToken() throws IOException {
    start.set(reader.getPosition());
    int ttype = st.nextToken();
    end.set(reader.getPosition());
    switch (ttype) {
    case StreamTokenizer.TT_EOF:
-      return EOF;
+      return YYEOF;
    case StreamTokenizer.TT_EOL:
      end.line += 1;
      end.column = 0;
@@ -160,7 +184,7 @@ class CalcLexer implements Calc.Lexer {
      end.set(reader.getPreviousPosition());
      return NUM;
    case ' ': case '\t':
-      return yylex();
+      return getToken();
    case '!':
      return BANG;
    case '+':
@@ -185,7 +209,9 @@ class CalcLexer implements Calc.Lexer {
  }
 }

-
+/**
+ * A class defining a point in the input.
+ */
 class Position {
  public int line = 1;
  public int column = 1;
@@ -227,6 +253,9 @@ class Position {
  }
 }

+/**
+ * A Stream reader that keeps track of the current Position.
+ */
 class PositionReader extends BufferedReader {

  private Position position = new Position();
@@ -93,7 +93,7 @@ class CalcLexer implements Calc.Lexer {
    int ttype = st.nextToken();
    switch (ttype) {
    case StreamTokenizer.TT_EOF:
-      return EOF;
+      return YYEOF;
    case StreamTokenizer.TT_EOL:
      return (int) '\n';
    case StreamTokenizer.TT_WORD:
@@ -25,7 +25,7 @@ medir=$(dirname "$1" | sed -e 's,.*examples/,,')
 number=1

 # Exit status of this script.
-exit=true
+status=0

 # top_builddir.
 cwd=$(pwd)
@@ -34,6 +34,13 @@ cwd=$(pwd)
 # See bistromathic.test.
 strip_prompt=false

+# If diff supports --strip-trailing-cr, use it, to avoid EOL issues
+# when testing Java programs on Windows.
+echo "checking for diff --strip-trailing-cr"
+if diff --strip-trailing-cr "$1" "$1"; then
+  diff_opts=--strip-trailing-cr
+fi
+
 # The exercised program.
 abs_medir=$cwd/examples/$medir
 if test -x "$abs_medir/$me"; then
@@ -68,26 +75,49 @@ trap cleanup 0 1 2 13 15
 mkdir $$.dir
 cd $$.dir

-# run [-noerr] EXPECTED-EXIT-STATUS EXPECTED-OUTPUT [PARSER-OPTIONS]
-# ------------------------------------------------------------------
+
+# skip [MSG]
+# ----------
+# Skip this test.
+skip ()
+{
+  if test x"$1" != x; then
+    echo "SKIP: $1"
+  fi
+  # See Autoconf's doc on 'trap'.
+  (exit 77); exit 77
+}
+
+
+# run [-noerr, -n] EXPECTED-EXIT-STATUS EXPECTED-OUTPUT [PARSER-OPTIONS]
+# ----------------------------------------------------------------------
 # -noerr: ignore stderr, otherwise merge it into effective output.
+# -n: not final end-of-line in expected-output
 run ()
 {
  noerr=false
-  case $1 in
-    (-noerr) noerr=true; shift;;
-  esac
+  echo=echo
+  while true; do
+    case $1 in
+      (-noerr) noerr=true; shift;;
+      (-n)     echo=printf; shift;;
+      (*)      break;;
+    esac
+  done

  # Expected exit status.
  sta_exp=$1
  shift

  # Expected output.
-  if $strip_prompt; then
-      out_exp=$(echo "$1" | sed -e 's/^> err:/err:/;/^> /d')
-  else
-      out_exp=$1
-  fi
+  $echo "$1" |
+    sed -e 's/Reducing stack by rule .* (line .*):/Reducing stack by rule XX (line XXX):/g' |
+    if $strip_prompt; then
+      # An extra EOL added in bistromathic's main.  Keep that empty line.
+      sed -e '/^> ./d;s/^> $//g'
+    else
+      cat
+    fi >exp
  shift

  # Effective exit status.
@@ -96,33 +126,42 @@ run ()
  prog "$@" - <input >out_eff 2>err_eff || sta_eff=$?

  # Combine effective output and error streams.
-  out_eff=$(cat out_eff && $noerr || sed -e 's/^/err: /g' err_eff)
+  {
+    cat out_eff
+    if ! $noerr; then
+       sed -e 's/^/err: /g' \
+           -e 's/Reducing stack by rule .* (line .*):/Reducing stack by rule XX (line XXX):/g' \
+           err_eff
+    fi
+  } >eff

  if test $sta_eff -eq $sta_exp; then
-    if test "$out_eff" = "$out_exp"; then
+    if diff $diff_opts eff exp >/dev/null 2>&1; then
      echo "$me: PASS: $number"
    else
      echo "$me: FAIL: $number"
      echo "$me: input:"
      sed -e 's/^/  /' input
      echo "$me: expected output:"
-      echo "$out_exp" | sed -e 's/^/  /'
+      sed -e 's/^/  /' exp
      echo "$me: effective output:"
-      echo "$out_eff" | sed -e 's/^/  /'
-      exit=false
+      sed -e 's/^/  /' eff
+      echo "$me: diff:"
+      diff $diff_opts -u exp eff | sed -e 's/^/  /'
+      status=1
    fi
  else
    echo "$me: FAIL: $number (expected status: $sta_exp, effective: $sta_eff)"
    cat err_eff
-    exit=false
+    status=1
  fi
  number=$(expr $number + 1)
 }

 # We have cd'd one level deeper.
 case $1 in
-  /*) . "$1";;
-  *)  . "../$1";;
+  /*) . "$1" || status=2;;
+  *)  . "../$1" || status=2;;
 esac

-$exit
+exit $status
@@ -1,3 +1,4 @@
+/remove-potcdate.sin~
 /*.gmo
 /*.po
 /LINGUAS
@@ -1,3 +1,4 @@
+/extern-inline.m4~
 /*~
 /00gnulib.m4
 /__inline.m4
@@ -41,6 +41,22 @@ else
 fi
 ])

+
+AC_CACHE_CHECK([whether flex supports --header=FILE],
+                [ac_cv_prog_lex_supports_header_opt],
+[if _AC_DO_VAR([LEX --header=conftest.h conftest.l]); then
+  ac_cv_prog_lex_supports_header_opt=yes
+else
+  ac_cv_prog_lex_supports_header_opt=no
+fi
+])
+if test "$ac_cv_prog_lex_supports_header_opt" = yes; then
+  FLEX_SUPPORTS_HEADER_OPT=true
+else
+  FLEX_SUPPORTS_HEADER_OPT=false
+fi
+
+
 cat >conftest.l <<_ACEOF[
 %%
 a { ECHO; }
@@ -1,3 +1,5 @@
+examples/c/bistromathic/parse.y
+examples/java/calc/Calc.y
 src/complain.c
 src/conflicts.c
 src/files.c
@@ -5,6 +7,7 @@ src/fixits.c
 src/getargs.c
 src/gram.c
 src/graphviz.c
+src/i18n-strings.c
 src/location.c
 src/main.c
 src/muscle-tab.c
@@ -23,7 +23,7 @@
 #include "system.h"

 #include <argmatch.h>
-#include <ctype.h>
+#include <c-ctype.h>
 #include <progname.h>
 #include <stdarg.h>
 #include <sys/stat.h>
@@ -600,7 +600,7 @@ syntax_error (location loc,
      CASE (2, _("expected %1$s before %0$s"));
      CASE (3, _("expected %1$s or %2$s before %0$s"));
      CASE (4, _("expected %1$s or %2$s or %3$s before %0$s"));
-      CASE (5, _("expected %1$s or %2$s or %4$s or %5$s before %0$s"));
+      CASE (5, _("expected %1$s or %2$s or %3$s or %4$s before %0$s"));
 #undef CASE
    }
  location_print (loc, stderr);
@@ -609,7 +609,7 @@ syntax_error (location loc,

  while (*format)
    if (format[0] == '%'
-        && isdigit (format[1])
+        && c_isdigit (format[1])
        && format[2] == '$'
        && format[3] == 's'
        && (format[1] - '0') < argc)
@@ -124,10 +124,11 @@ fixits_run (void)
  FILE *out = xfopen (input, "w");
  size_t line = 1;
  size_t offset = 1;
-  fixit const *f = NULL;
+  void const *p = NULL;
  gl_list_iterator_t iter = gl_list_iterator (fixits);
-  while (gl_list_iterator_next (&iter, (const void**) &f, NULL))
+  while (gl_list_iterator_next (&iter, &p, NULL))
    {
+      fixit const *f = p;
      /* Look for the correct line. */
      while (line < f->location.start.line)
        {
@@ -0,0 +1,37 @@
+/* This file is not compiled in, it is used only to expose more
+   strings to gettextize.
+
+   Why is this needed?
+
+   Bison emits strings to translate in the generated code, for builtin
+   tokens.  So they appear only in generated parsers, which are not
+   shipped, so they are not in the src tree, so we cannot use them in
+   our POTFILE.
+
+   Except src/parse-gram.c, which is in the source tree.  And even in
+   the git repo.  But to avoid useless diffs in the repo, we do not
+   keep the #line directives in the src tree.  Yet, for the user, we
+   ship a src/parse-gram.c _with_ the #lines.  This is done in a
+   dist-hook which regenerates src/parse-gram.c when we run "make
+   dist".
+
+   Unfortunately, then, update-po traverses the whole tree and sees
+   that the location of the strings to translate in src/parse-gram.c
+   have changed, so the bison.pot is to be updated.  And that is not
+   possible in the "make dist" which is run within "make distcheck"
+   (not the one preparing the dist for distcheck, the one run by
+   distcheck to check that a distributed tarball can build a tarball)
+   because then the src tree is read-only.
+
+   So let's not put src/parse-gram.c in the POTFILE, and expose these
+   strings to gettextize by hand.
+  */
+
+// Please syntax-check.
+#include <config.h>
+
+static const char *const msgid[] =
+  {
+    N_("end of file"),
+    N_("invalid token")
+  }
@@ -92,7 +92,7 @@ goto_print (goto_number i, FILE *out)
  const state_number dst = to_state[i];
  symbol_number var = states[dst]->accessing_symbol;
  fprintf (out,
-           "goto[%ld] = (%d, %s, %d)", i, src, symbols[var]->tag, dst);
+           "goto[%zu] = (%d, %s, %d)", i, src, symbols[var]->tag, dst);
 }

 void
@@ -117,6 +117,7 @@ BUILT_SOURCES +=                                \
 # definition of libbison, beware that they might expand as flags such as
 # `-lm`.  Keep them here.  Or use a Libtool convenience library.
 src_bison_LDADD =                               \
+  lib/libbison.a                                \
  $(ISNAND_LIBM)                                \
  $(ISNANF_LIBM)                                \
  $(ISNANL_LIBM)                                \
@@ -126,10 +127,10 @@ src_bison_LDADD =                               \
  $(LIBTHREAD)                                  \
  $(LIB_CLOCK_GETTIME)                          \
  $(LIB_GETHRXTIME)                             \
-  $(LIBTEXTSTYLE)                               \
-  lib/libbison.a
+  $(LIBTEXTSTYLE)


+EXTRA_DIST += %D%/i18n-strings.c


 ## ------ ##
@@ -186,16 +186,6 @@ xescape_trigraphs (const char *src)
  return buf;
 }

-/* Whether some symbol requires internationalization.  */
-static bool
-has_translations (void)
-{
-  for (int i = 0; i < nsyms; i++)
-    if (symbols[i]->translatable)
-      return true;
-  return false;
-}
-
 /* The tag to show in the generated parsers.  Use "end of file" rather
   than "$end".  But keep "$end" in the reports, it's shorter and more
   consistent.  Support i18n if the user already uses it.  */
@@ -219,11 +209,9 @@ symbol_tag (const symbol *sym)
 static void
 prepare_symbol_names (char const *muscle_name)
 {
-  const bool eof_is_user_defined
-    = !endtoken->alias || STRNEQ (endtoken->alias->tag, "$end");
-
+  // Whether to add a pair of quotes around the name.
  const bool quote = STREQ (muscle_name, "tname");
-  const bool with_translations = !quote && has_translations ();
+  bool has_translations = false;

  /* We assume that the table will be output starting at column 2. */
  int col = 2;
@@ -233,11 +221,9 @@ prepare_symbol_names (char const *muscle_name)
  for (int i = 0; i < nsyms; i++)
    {
      const char *tag = symbol_tag (symbols[i]);
-      bool translatable =
-        with_translations
-        && (symbols[i]->translatable
-            || (!eof_is_user_defined && symbols[i]->content == endtoken->content)
-            || symbols[i]->content == undeftoken->content);
+      bool translatable = !quote && symbols[i]->translatable;
+      if (translatable)
+        has_translations = true;

      char *cp
        = tag[0] == '"' && !quote
@@ -273,8 +259,7 @@ prepare_symbol_names (char const *muscle_name)
  muscle_insert (muscle_name, obstack_finish0 (&format_obstack));

  /* Announce whether translation support is needed.  */
-  if (!quote)
-    MUSCLE_INSERT_BOOL ("has_translations", with_translations);
+  MUSCLE_INSERT_BOOL ("has_translations_flag", has_translations);
 }


@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.5.4.236-8d75.  */
+/* A Bison parser, made by GNU Bison 3.6.  */

 /* Bison implementation for Yacc-like parsers in C

@@ -34,6 +34,10 @@
 /* C LALR(1) parser skeleton written by Richard Stallman, by
   simplifying the original so-called "semantic" parser.  */

+/* DO NOT RELY ON FEATURES THAT ARE NOT DOCUMENTED in the manual,
+   especially those whose name start with YY_ or yy_.  They are
+   private implementation details that can be changed or removed.  */
+
 /* All symbols defined below should begin with yy or YY, to avoid
   infringing on user name space.  This should be done even for local
   variables, as they might otherwise be expanded by user macros.
@@ -41,14 +45,11 @@
   define necessary library symbols; they are noted "INFRINGES ON
   USER NAME SPACE" below.  */

-/* Undocumented macros, especially those whose name start with YY_,
-   are private implementation details.  Do not rely on them.  */
-
 /* Identify Bison output.  */
 #define YYBISON 1

 /* Bison version.  */
-#define YYBISON_VERSION "3.5.4.236-8d75"
+#define YYBISON_VERSION "3.6"

 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -105,7 +106,7 @@ enum yysymbol_kind_t
 {
  YYSYMBOL_YYEMPTY = -2,
  YYSYMBOL_YYEOF = 0,                      /* "end of file"  */
-  YYSYMBOL_YYERROR = 1,                    /* error  */
+  YYSYMBOL_YYerror = 1,                    /* error  */
  YYSYMBOL_YYUNDEF = 2,                    /* "invalid token"  */
  YYSYMBOL_STRING = 3,                     /* "string"  */
  YYSYMBOL_TSTRING = 4,                    /* "translatable string"  */
@@ -407,6 +408,7 @@ typedef int yytype_uint16;

 #define YYSIZEOF(X) YY_CAST (YYPTRDIFF_T, sizeof (X))

+
 /* Stored state numbers (used for stacks). */
 typedef yytype_uint8 yy_state_t;

@@ -425,6 +427,11 @@ typedef int yy_state_fast_t;
 # endif
 #endif

+#ifndef N_
+# define N_(Msgid) Msgid
+#endif
+
+
 #ifndef YY_ATTRIBUTE_PURE
 # if defined __GNUC__ && 2 < __GNUC__ + (96 <= __GNUC_MINOR__)
 #  define YY_ATTRIBUTE_PURE __attribute__ ((__pure__))
@@ -524,7 +531,7 @@ void free (void *); /* INFRINGES ON USER NAME SPACE */
 #  endif
 # endif
 # define YYCOPY_NEEDED 1
-#endif
+#endif /* 1 */

 #if (! defined yyoverflow \
     && (! defined __cplusplus \
@@ -643,7 +650,7 @@ yysymbol_name (yysymbol_kind_t yysymbol)
 {
  static const char *const yy_sname[] =
  {
-  N_("end of file"), "error", N_("invalid token"), N_("string"),
+  N_("end of file"), N_("error"), N_("invalid token"), N_("string"),
  N_("translatable string"), "%token", "%nterm", "%type", "%destructor",
  "%printer", "%left", "%right", "%nonassoc", "%precedence", "%prec",
  "%dprec", "%merge", "%code", "%default-prec", "%define", "%defines",
@@ -666,11 +673,11 @@ yysymbol_name (yysymbol_kind_t yysymbol)
  "named_ref.opt", "variable", "value", "id", "id_colon", "symbol",
  "string_as_id", "epilogue.opt", YY_NULLPTR
  };
-  /* YYTRANSLATABLE[SYMBOL-NUM] -- Whether YYTNAME[SYMBOL-NUM] is
+  /* YYTRANSLATABLE[SYMBOL-NUM] -- Whether YY_SNAME[SYMBOL-NUM] is
     internationalizable.  */
  static yytype_int8 yytranslatable[] =
  {
-       0,     0,     0,     1,     1,     0,     0,     0,     0,     0,
+       1,     1,     1,     1,     1,     0,     0,     0,     0,     0,
       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
       0,     0,     0,     0,     0,     0,     0,     0,     0,     0,
@@ -684,7 +691,7 @@ yysymbol_name (yysymbol_kind_t yysymbol)
 }
 #endif

-# ifdef YYPRINT
+#ifdef YYPRINT
 /* YYTOKNUM[NUM] -- (External) token number corresponding to the
   (internal) symbol number NUM (which must be that of a token).  */
 static const yytype_int16 yytoknum[] =
@@ -697,7 +704,7 @@ static const yytype_int16 yytoknum[] =
     305,   306,   307,   308,   309,   310,   311,   312,   313,   314,
     315
 };
-# endif
+#endif

 #define YYPACT_NINF (-80)

@@ -925,6 +932,9 @@ enum { YYENOMEM = -2 };
      }                                                           \
  while (0)

+/* Backward compatibility with an undocumented macro.
+   Use GRAM_error or GRAM_UNDEF. */
+#define YYERRCODE GRAM_UNDEF

 /* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].
   If N is 0, then set CURRENT to the empty location which ends
@@ -972,8 +982,8 @@ do {                                            \
   This macro was not mandated originally: define only if we know
   we won't break user code: when these are the locations we know.  */

-#ifndef YY_LOCATION_PRINT
-# if defined GRAM_LTYPE_IS_TRIVIAL && GRAM_LTYPE_IS_TRIVIAL
+# ifndef YY_LOCATION_PRINT
+#  if defined GRAM_LTYPE_IS_TRIVIAL && GRAM_LTYPE_IS_TRIVIAL

 /* Print *YYLOCP on YYO.  Private, do not rely on its existence. */

@@ -1003,22 +1013,22 @@ yy_location_print_ (FILE *yyo, YYLTYPE const * const yylocp)
  return res;
 }

-#  define YY_LOCATION_PRINT(File, Loc)          \
+#   define YY_LOCATION_PRINT(File, Loc)          \
  yy_location_print_ (File, &(Loc))

-# else
-#  define YY_LOCATION_PRINT(File, Loc) ((void) 0)
-# endif
-#endif
+#  else
+#   define YY_LOCATION_PRINT(File, Loc) ((void) 0)
+#  endif
+# endif /* !defined YY_LOCATION_PRINT */


-# define YY_SYMBOL_PRINT(Title, Type, Value, Location)                    \
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)                    \
 do {                                                                      \
  if (yydebug)                                                            \
    {                                                                     \
      YYFPRINTF (stderr, "%s ", Title);                                   \
      yy_symbol_print (stderr,                                            \
-                  Type, Value, Location); \
+                  Kind, Value, Location); \
      YYFPRINTF (stderr, "\n");                                           \
    }                                                                     \
 } while (0)
@@ -1295,8 +1305,8 @@ yy_reduce_print (yy_state_t *yyssp, YYSTYPE *yyvsp, YYLTYPE *yylsp,
      YYFPRINTF (stderr, "   $%d = ", yyi + 1);
      yy_symbol_print (stderr,
                       YY_ACCESSING_SYMBOL (+yyssp[yyi + 1 - yynrhs]),
-                       &yyvsp[(yyi + 1) - (yynrhs)]
-                       , &(yylsp[(yyi + 1) - (yynrhs)])                       );
+                       &yyvsp[(yyi + 1) - (yynrhs)],
+                       &(yylsp[(yyi + 1) - (yynrhs)]));
      YYFPRINTF (stderr, "\n");
    }
 }
@@ -1312,7 +1322,7 @@ do {                                    \
 int yydebug;
 #else /* !GRAM_DEBUG */
 # define YYDPRINTF(Args) ((void) 0)
-# define YY_SYMBOL_PRINT(Title, Type, Value, Location)
+# define YY_SYMBOL_PRINT(Title, Kind, Value, Location)
 # define YY_STACK_PRINT(Bottom, Top)
 # define YY_REDUCE_PRINT(Rule)
 #endif /* !GRAM_DEBUG */
@@ -1606,7 +1616,7 @@ yypcontext_expected_tokens (const yypcontext_t *yyctx,
  for (yyx = 0; yyx < YYNTOKENS; ++yyx)
    {
      yysymbol_kind_t yysym = YY_CAST (yysymbol_kind_t, yyx);
-      if (yysym != YYSYMBOL_YYERROR && yysym != YYSYMBOL_YYUNDEF)
+      if (yysym != YYSYMBOL_YYerror && yysym != YYSYMBOL_YYUNDEF)
        switch (yy_lac (yyctx->yyesa, yyctx->yyes, yyctx->yyes_capacity, yyctx->yyssp, yysym))
          {
          case YYENOMEM:
@@ -1622,6 +1632,8 @@ yypcontext_expected_tokens (const yypcontext_t *yyctx,
              yyarg[yycount++] = yysym;
          }
    }
+  if (yyarg && yycount == 0 && 0 < yyargn)
+    yyarg[0] = YYSYMBOL_YYEMPTY;
  return yycount;
 }

@@ -1901,7 +1913,7 @@ yysetstate:
        YYSTACK_RELOCATE (yyss_alloc, yyss);
        YYSTACK_RELOCATE (yyvs_alloc, yyvs);
        YYSTACK_RELOCATE (yyls_alloc, yyls);
-# undef YYSTACK_RELOCATE
+#  undef YYSTACK_RELOCATE
        if (yyss1 != yyssa)
          YYSTACK_FREE (yyss1);
      }
@@ -1954,6 +1966,17 @@ yybackup:
      yytoken = YYSYMBOL_YYEOF;
      YYDPRINTF ((stderr, "Now at end of input.\n"));
    }
+  else if (yychar == GRAM_error)
+    {
+      /* The scanner already issued an error message, process directly
+         to error recovery.  But do not keep the error token as
+         lookahead, it is too special and may lead us to an endless
+         loop in error recovery. */
+      yychar = GRAM_UNDEF;
+      yytoken = YYSYMBOL_YYerror;
+      yyerror_range[1] = yylloc;
+      goto yyerrlab1;
+    }
  else
    {
      yytoken = YYTRANSLATE (yychar);
@@ -2619,7 +2642,6 @@ yyerrlab:
  /* Make sure we have latest lookahead translation.  See comments at
     user semantic actions for why this is necessary.  */
  yytoken = yychar == GRAM_EMPTY ? YYSYMBOL_YYEMPTY : YYTRANSLATE (yychar);
-
  /* If not already recovering from an error, report this error.  */
  if (!yyerrstatus)
    {
@@ -2635,7 +2657,6 @@ yyerrlab:
    }

  yyerror_range[1] = yylloc;
-
  if (yyerrstatus == 3)
    {
      /* If just tried and failed to reuse lookahead token after an
@@ -2684,13 +2705,14 @@ yyerrorlab:
 yyerrlab1:
  yyerrstatus = 3;      /* Each real token shifted decrements this.  */

+  /* Pop stack until we find a state that shifts the error token.  */
  for (;;)
    {
      yyn = yypact[yystate];
      if (!yypact_value_is_default (yyn))
        {
-          yyn += YYSYMBOL_YYERROR;
-          if (0 <= yyn && yyn <= YYLAST && yycheck[yyn] == YYSYMBOL_YYERROR)
+          yyn += YYSYMBOL_YYerror;
+          if (0 <= yyn && yyn <= YYLAST && yycheck[yyn] == YYSYMBOL_YYerror)
            {
              yyn = yytable[yyn];
              if (0 < yyn)
@@ -2719,10 +2741,8 @@ yyerrlab1:
  YY_IGNORE_MAYBE_UNINITIALIZED_END

  yyerror_range[2] = yylloc;
-  /* Using YYLLOC is tempting, but would change the location of
-     the lookahead.  YYLOC is available though.  */
-  YYLLOC_DEFAULT (yyloc, yyerror_range, 2);
-  *++yylsp = yyloc;
+  ++yylsp;
+  YYLLOC_DEFAULT (*yylsp, yyerror_range, 2);

  /* Shift the error token.  */
  YY_SYMBOL_PRINT ("Shifting", YY_ACCESSING_SYMBOL (yyn), yyvsp, yylsp);
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.5.4.236-8d75.  */
+/* A Bison parser, made by GNU Bison 3.6.  */

 /* Bison interface for Yacc-like parsers in C

@@ -31,8 +31,9 @@
   This special exception was added by the Free Software Foundation in
   version 2.2 of Bison.  */

-/* Undocumented macros, especially those whose name start with YY_,
-   are private implementation details.  Do not rely on them.  */
+/* DO NOT RELY ON FEATURES THAT ARE NOT DOCUMENTED in the manual,
+   especially those whose name start with YY_ or yy_.  They are
+   private implementation details that can be changed or removed.  */

 #ifndef YY_GRAM_SRC_PARSE_GRAM_H_INCLUDED
 # define YY_GRAM_SRC_PARSE_GRAM_H_INCLUDED
@@ -79,7 +80,7 @@ extern int gram_debug;
  {
    GRAM_EMPTY = -2,
    GRAM_EOF = 0,                  /* "end of file"  */
-    GRAM_ERRCODE = 1,              /* error  */
+    GRAM_error = 1,                /* error  */
    GRAM_UNDEF = 2,                /* "invalid token"  */
    STRING = 3,                    /* "string"  */
    TSTRING = 4,                   /* "translatable string"  */
@@ -83,6 +83,23 @@ static boundary scanner_cursor;
      unput (Msg[i - 1]);                                       \
  } while (0)

+
+#define STRING_GROW_ESCAPE(Char)                                \
+  do {                                                          \
+    long c = Char;                                              \
+    if (0 < c && c <= UCHAR_MAX)                                \
+      obstack_1grow (&obstack_for_string, c);                   \
+    else                                                        \
+      {                                                         \
+        complain (loc, complaint,                               \
+                  _("invalid number after \\-escape: %s"),      \
+                  yytext + 1);                                  \
+        /* Avoid additional errors about empty char literal. */ \
+        obstack_1grow (&obstack_for_string, '?');               \
+      }                                                         \
+  } while (0)
+
+
 /* The current file name.  Might change with #line.  */
 static uniqstr current_file = NULL;

@@ -290,6 +307,7 @@ eqopt    ({sp}=)?

  "%"{id} {
    complain (loc, complaint, _("invalid directive: %s"), quote (yytext));
+    return GRAM_error;
  }

  ":"                     return COLON;
@@ -311,6 +329,7 @@ eqopt    ({sp}=)?
     accept "1FOO" as "1 FOO".  */
  {int}{id} {
    complain (loc, complaint, _("invalid identifier: %s"), quote (yytext));
+    return GRAM_error;
  }

  /* Characters.  */
@@ -361,10 +380,11 @@ eqopt    ({sp}=)?
    BEGIN SC_BRACKETED_ID;
  }

-  [^\[%A-Za-z0-9_<>{}\"\'*;|=/, \f\r\n\t\v]+|. {
+  [^\[%A-Za-z0-9_<>{}""''*;|=/, \f\r\n\t\v]+|. {
    complain (loc, complaint, "%s: %s",
              ngettext ("invalid character", "invalid characters", yyleng),
              quote_mem (yytext, yyleng));
+    return GRAM_error;
  }

  <<EOF>> {
@@ -381,7 +401,11 @@ eqopt    ({sp}=)?

 <SC_ESCAPED_CHARACTER,SC_ESCAPED_STRING,SC_ESCAPED_TSTRING,SC_TAG>
 {
-  \0        complain (loc, complaint, _("invalid null character"));
+  \0         {
+    complain (loc, complaint, _("invalid null character"));
+    STRING_FREE;
+    return GRAM_error;
+  }
 }


@@ -437,6 +461,7 @@ eqopt    ({sp}=)?
        complain (loc, complaint,
                  _("unexpected identifier in bracketed name: %s"),
                  quote (yytext));
+        return GRAM_error;
      }
    else
      {
@@ -457,7 +482,10 @@ eqopt    ({sp}=)?
          }
      }
    else
-      complain (loc, complaint, _("an identifier expected"));
+      {
+        complain (loc, complaint, _("an identifier expected"));
+        return GRAM_error;
+      }
  }

  [^\].A-Za-z0-9_/ \f\r\n\t\v]+|. {
@@ -465,6 +493,7 @@ eqopt    ({sp}=)?
              ngettext ("invalid character in bracketed name",
                        "invalid characters in bracketed name", yyleng),
              quote_mem (yytext, yyleng));
+    return GRAM_error;
  }

  <<EOF>> {
@@ -563,22 +592,27 @@ eqopt    ({sp}=)?
 {
  "'" {
    STRING_FINISH;
+    BEGIN INITIAL;
    loc->start = token_start;
    val->CHAR = last_string[0];

-    /* FIXME: Eventually, make these errors.  */
    if (last_string[0] == '\0')
-    {
-      complain (loc, Wother, _("empty character literal"));
-      /* '\0' seems dangerous even if we are about to complain.  */
-      val->CHAR = '\'';
-    }
+      {
+        complain (loc, complaint, _("empty character literal"));
+        STRING_FREE;
+        return GRAM_error;
+      }
    else if (last_string[1] != '\0')
-      complain (loc, Wother,
-                _("extra characters in character literal"));
-    STRING_FREE;
-    BEGIN INITIAL;
-    return CHAR;
+      {
+        complain (loc, complaint, _("extra characters in character literal"));
+        STRING_FREE;
+        return GRAM_error;
+      }
+    else
+      {
+        STRING_FREE;
+        return CHAR;
+      }
  }
  {eol}     unexpected_newline (token_start, "'");
  <<EOF>>   unexpected_eof (token_start, "'");
@@ -620,22 +654,12 @@ eqopt    ({sp}=)?
 {
  \\[0-7]{1,3} {
    verify (UCHAR_MAX < ULONG_MAX);
-    long c = strtol (yytext + 1, NULL, 8);
-    if (0 < c && c <= UCHAR_MAX)
-      obstack_1grow (&obstack_for_string, c);
-    else
-      complain (loc, complaint, _("invalid number after \\-escape: %s"),
-                yytext+1);
+    STRING_GROW_ESCAPE (strtol (yytext + 1, NULL, 8));
  }

  \\x[0-9abcdefABCDEF]+ {
    verify (UCHAR_MAX < ULONG_MAX);
-    long c = strtol (yytext + 2, NULL, 16);
-    if (0 < c && c <= UCHAR_MAX)
-      obstack_1grow (&obstack_for_string, c);
-    else
-      complain (loc, complaint, _("invalid number after \\-escape: %s"),
-                yytext+1);
+    STRING_GROW_ESCAPE (strtol (yytext + 2, NULL, 16));
  }

  \\a   obstack_1grow (&obstack_for_string, '\a');
@@ -650,13 +674,9 @@ eqopt    ({sp}=)?
  \\("\""|"'"|"?"|"\\")  obstack_1grow (&obstack_for_string, yytext[1]);

  \\(u|U[0-9abcdefABCDEF]{4})[0-9abcdefABCDEF]{4} {
-    int c = convert_ucn_to_byte (yytext);
-    if (c <= 0)
-      complain (loc, complaint, _("invalid number after \\-escape: %s"),
-                yytext+1);
-    else
-      obstack_1grow (&obstack_for_string, c);
+    STRING_GROW_ESCAPE (convert_ucn_to_byte (yytext));
  }
+
  \\(.|{eol})      {
    char const *p = yytext + 1;
    /* Quote only if escaping won't make the character visible.  */
@@ -666,6 +686,7 @@ eqopt    ({sp}=)?
      p = quotearg_style_mem (escape_quoting_style, p, 1);
    complain (loc, complaint, _("invalid character after \\-escape: %s"),
              p);
+    obstack_1grow (&obstack_for_string, '?');
  }
 }

@@ -84,7 +84,7 @@ static void fail_for_invalid_at (char const *at);
 "@output("      at_init (&argc, argv, &at_ptr, &at_output);

  /* This pattern must not match more than the previous @ patterns. */
-@[^@{}\'(\n]*   fail_for_invalid_at (yytext);
+@[^@{}''(\n]*   fail_for_invalid_at (yytext);
 \n              out_lineno++; ECHO;
 [^@\n]+         ECHO;

@@ -67,7 +67,10 @@
   Conflict resolution can decide that certain tokens in certain
   states should explicitly be errors (for implementing %nonassoc).
   For each state, the tokens that are errors for this reason are
-   recorded in an errs structure, which holds the token numbers.
+   recorded in an errs structure.  The generated parser does not
+   depend on this errs structure, it is used only in the reports
+   (*.output, etc.) to describe conflicted actions that have been
+   discarded.

   There is at least one goto transition present in state zero.  It
   leads to a next-to-final state whose accessing_symbol is the
@@ -847,8 +847,8 @@ symbols_new (void)
  accept->content->class = nterm_sym;
  accept->content->number = nvars++;

-  /* Construct the YYERRCODE/"error" token */
-  errtoken = symbol_get ("YYERRCODE", empty_loc);
+  /* Construct the YYerror/"error" token */
+  errtoken = symbol_get ("YYerror", empty_loc);
  errtoken->content->class = token_sym;
  errtoken->content->number = ntokens++;
  {
@@ -1095,6 +1095,21 @@ symbols_token_translations_init (void)
 }


+/* Whether some symbol requires internationalization.  */
+static bool
+has_translations (void)
+{
+  for (const void *entry = hash_get_first (symbol_table);
+       entry;
+       entry = hash_get_next (symbol_table, entry))
+    {
+      const symbol *sym = (const symbol *) entry;
+      if (sym->translatable)
+        return true;
+    }
+  return false;
+}
+
 /*----------------------------------------------------------------.
 | Assign symbol numbers, and write definition of token names into |
 | FDEFINES.  Set up vectors SYMBOL_TABLE, TAGS of symbols.        |
@@ -1137,6 +1152,18 @@ symbols_pack (void)
    complain (&startsymbol_loc, fatal,
              _("the start symbol %s is a token"),
              startsymbol->tag);
+
+  // If some user tokens are internationalized, the internal ones
+  // should be too.
+  if (has_translations ())
+    {
+      const bool eof_is_user_defined
+        = !endtoken->alias || STRNEQ (endtoken->alias->tag, "$end");
+      if (!eof_is_user_defined)
+        endtoken->alias->translatable = true;
+      undeftoken->alias->translatable = true;
+      errtoken->alias->translatable = true;
+    }
 }

 /*---------------------------------.
@@ -144,3 +144,44 @@ export LC_CTYPE

 # Empty if no xsltproc was found
 : ${XSLTPROC='@XSLTPROC@'}
+
+
+# Some tests expect a precise diff format.  See AT_DIFF_U_CHECK.
+# See https://lists.gnu.org/r/bug-bison/2020-05/msg00049.html.
+cat >conftest.1 <<EOF
+1
+2
+3
+4
+5
+6
+EOF
+
+cat >conftest.2 <<EOF
+1
+22
+3
+4
+55
+6
+EOF
+
+cat >conftest.expected <<EOF
+@@ -1,6 +1,6 @@
+ 1
+-2
+22
+ 3
+ 4
+-5
+55
+ 6
+EOF
+
+diff -u conftest.1 conftest.2 2>/dev/null | sed -n '/^@@/,$p' | sed 's/^ $//' >conftest.diff
+if diff conftest.expected conftest.diff >/dev/null; then
+    DIFF_U_WORKS=true
+else
+    DIFF_U_WORKS=false
+fi
+rm conftest.*
@@ -109,11 +109,6 @@ AT_DATA_GRAMMAR([list.yy],
 %define parse.assert
 %debug

-%code top
-{
-  // Get access to stack_symbol_type for the tests.
-# define private public
-}
 %code provides
 {
  ]AT_YYLEX_DECLARE[
@@ -136,6 +131,14 @@ AT_DATA_GRAMMAR([list.yy],
 %code requires { #include <vector> }
 %code { int yylex (yy::parser::semantic_type* lvalp); }

+// A hack which relies on internal hooks to check stack_symbol_type,
+// which is private.
+%code yy_bison_internal_hook {
+  public:
+    typedef stack_symbol_type yy_stack_symbol_type;
+    typedef stack_type yy_stack_type;
+}
+
 %%
 exp: "int" { $$.push_back ($1); }
 %%
@@ -157,6 +160,9 @@ int main()
  // symbol_type: construction, accessor.
  {
    parser::symbol_type s = parser::make_INT (12);
+    assert_eq (s.kind (), parser::symbol_kind::S_INT);
+    assert_eq (parser::symbol_name (s.kind ()), std::string ("\"int\""));
+    assert_eq (s.name (), std::string ("\"int\""));
    assert_eq (s.value.as<int> (), 12);
  }

@@ -180,12 +186,13 @@ int main()
  }

  // stack_symbol_type: construction, accessor.
+  typedef parser::yy_stack_symbol_type stack_symbol_type;
  {
 #if 201103L <= YY_CPLUSPLUS
-    auto ss = parser::stack_symbol_type(1, parser::make_INT(123));
+    auto ss = stack_symbol_type (1, parser::make_INT(123));
 #else
    parser::symbol_type s = parser::make_INT (123);
-    parser::stack_symbol_type ss(1, s);
+    stack_symbol_type ss(1, s);
 #endif
    assert_eq (ss.value.as<int> (), 123);
  }
@@ -194,17 +201,17 @@ int main()
  // Sufficiently many so that it will be resized.
  // Probably 3 times (starting at 200).
  {
-    parser::stack_type st;
+    parser::yy_stack_type st;
    const int mucho = 1700;
    const int int_reduction_state = 1; // Read list.output to find it.
    for (int i = 0; i < mucho; ++i)
      {
 #if 201103L <= YY_CPLUSPLUS
-        st.push(parser::stack_symbol_type{int_reduction_state,
-                                          parser::make_INT (i)});
+        st.push(stack_symbol_type{int_reduction_state,
+                                  parser::make_INT (i)});
 #else
        parser::symbol_type s = parser::make_INT (i);
-        parser::stack_symbol_type ss (int_reduction_state, s);
+        stack_symbol_type ss (int_reduction_state, s);
        st.push (ss);
 #endif
      }
@@ -201,8 +201,8 @@ read_integer (]AT_YYLEX_FORMALS[)
  /* Skip white spaces.  */
  do
    {
-]AT_LOCATION_IF(
-[     AT_LOC_FIRST_COLUMN = AT_LOC_LAST_COLUMN;
+]AT_LOCATION_IF([
+      AT_LOC_FIRST_COLUMN = AT_LOC_LAST_COLUMN;
      AT_LOC_FIRST_LINE   = AT_LOC_LAST_LINE;
 ])[
    }
@@ -220,6 +220,15 @@ read_integer (]AT_YYLEX_FORMALS[)
  if (c == EOF)
    return ]AT_TOKEN_PREFIX[CALC_EOF;

+  /* An explicit error raised by the scanner. */
+  if (c == '#')
+    {]AT_LOCATION_IF([
+      fprintf (stderr, "%d.%d: ",
+               AT_LOC_FIRST_LINE, AT_LOC_FIRST_COLUMN);])[
+      fputs ("syntax error: invalid character: '#'\n", stderr);
+      return ]AT_TOKEN_PREFIX[]AT_API_PREFIX[error;
+    }
+
  /* Return single chars. */
  return c;
 }
@@ -304,7 +313,7 @@ class CalcLexer(R) : Lexer
        location.end.column += 1;]])[
      }

-    // Handle EOF.
+    // EOF.
    if (input.empty)
      return TokenKind.CALC_EOF;

@@ -325,6 +334,14 @@ class CalcLexer(R) : Lexer
    else
      location.end.column += 1;]])[
    input.popFront;
+
+    // An explicit error raised by the scanner. */
+    if (c == '#')
+      {
+        stderr.writeln (]AT_LOCATION_IF([location, ": ", ])["syntax error: invalid character: '#'");
+        return TokenKind.YYerror;
+      }
+
    return c;
  }
 }
@@ -370,12 +387,12 @@ m4_define([AT_CALC_YYLEX(java)],

  public int yylex () throws IOException {;]AT_LOCATION_IF([[
    start.set (reader.getPosition ());]])[
-    int ttype = st.nextToken ();]AT_LOCATION_IF([[
+    int tkind = st.nextToken ();]AT_LOCATION_IF([[
    end.set (reader.getPosition ());]])[
-    switch (ttype)
+    switch (tkind)
      {
      case StreamTokenizer.TT_EOF:
-        return EOF;
+        return CALC_EOF;
      case StreamTokenizer.TT_EOL:;]AT_LOCATION_IF([[
        end.line += 1;
        end.column = 0;]])[
@@ -386,8 +403,11 @@ m4_define([AT_CALC_YYLEX(java)],
        return NUM;
      case ' ': case '\t':
        return yylex ();
+      case '#':
+        System.err.println(]AT_LOCATION_IF([[start + ": " + ]])["syntax error: invalid character: '#'");
+        return YYerror;
      default:
-        return ttype;
+        return tkind;
      }
  }
 ]AT_LEXPARAM_IF([], [[}]])[
@@ -763,8 +783,8 @@ AT_JAVA_IF(
  [AT_PARSER_CHECK([calc input],        0, [AT_PARAM_IF([m4_n([$3])])], [stderr])])
 AT_LANG_MATCH([c\|c++\|java],
  [AT_GLR_IF([],
-    [AT_CHECK([grep -v 'Return for a new token:' stderr | wc -l],
-              [0],
+    [AT_CHECK([grep -c -v 'Return for a new token:' stderr],
+              [ignore],
              [m4_n([AT_DEBUG_IF([$4], [0])])])])])
 ])

@@ -1004,6 +1024,35 @@ _AT_CHECK_CALC_ERROR([$1], [0], [(* *) + (*) + (*)],
 ]AT_JAVA_IF([1.10-1.11], [1.10])[: syntax error on token ['*'] (expected: [number] ['-'] ['('] ['!'])
 ]AT_JAVA_IF([1.16-1.17], [1.16])[: syntax error on token ['*'] (expected: [number] ['-'] ['('] ['!'])]])

+
+# YYerror.
+# --------
+# Check that returning YYerror from the scanner properly enters
+# error-recovery without issuing a second error message.
+
+_AT_CHECK_CALC_ERROR([$1], [0], [(#) + (#) = 2222],
+                     [[final: 2222 0 0]],
+                     [102],
+[[1.2: syntax error: invalid character: '#'
+1.8: syntax error: invalid character: '#']])
+
+_AT_CHECK_CALC_ERROR([$1], [0], [(1 + #) = 1111],
+                     [[final: 1111 0 0]],
+                     [102],
+[[1.6: syntax error: invalid character: '#']])
+
+_AT_CHECK_CALC_ERROR([$1], [0], [(# + 1) = 1111],
+                     [[final: 1111 0 0]],
+                     [102],
+[[1.2: syntax error: invalid character: '#']])
+
+_AT_CHECK_CALC_ERROR([$1], [0], [(1 + # + 1) = 1111],
+                     [[final: 1111 0 0]],
+                     [102],
+[[1.6: syntax error: invalid character: '#']])
+
+
+
 AT_BISON_OPTION_POPDEFS

 AT_CLEANUP
@@ -19,7 +19,7 @@ AT_BANNER([[Diagnostics.]])


 # AT_TEST($1: TITLE, $2: GRAMMAR, $3: EXIT-STATUS, $4: OUTPUT-WITH-STYLE,
-#         $5: EXTRA_ENV
+#         $5: EXTRA_ENV, $6: SKIP-IF)
 # -----------------------------------------------------------------------
 # Run Bison on GRAMMAR with debugging style enabled, and expect
 # OUTPUT-WITH-STYLE as diagnostics.
@@ -33,6 +33,9 @@ AT_KEYWORDS([diagnostics])
 locale=`locale -a | $EGREP '^en_US\.(UTF-8|utf8)$' | sed 1q`
 AT_SKIP_IF([test x == x"$locale"])

+m4_ifval([$6],
+[AT_SKIP_IF([$6])])
+
 AT_BISON_OPTION_PUSHDEFS

 AT_DATA_GRAMMAR([[input.y]], [$2])
@@ -220,15 +223,14 @@ exp: an\005error.

 AT_TEST([[Tabulations and multibyte characters]],
 [[%%
-exp: a b c d e f g h
+exp: a b c d e f g
 a: {		}
 b: {            }
 c: {------------}
 d: {éééééééééééé}
-e: {∇⃗×𝐸⃗ = -∂𝐵⃗/∂t}
-f: {	42	}
-g: {	"฿¥$€₦"	}
-h: {	🐃	}
+e: {	42	}
+f: {	"฿¥$€₦"	}
+g: {	🐃	}
 ]],
 [0],
 [[input.y:11.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
@@ -248,25 +250,37 @@ input.y:14.4-17: <warning>warning:</warning> empty rule without %empty [<warning
      |    <warning>^~~~~~~~~~~~~~</warning>
      |    <fixit-insert>%empty</fixit-insert>
 input.y:15.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
-   15 | e: <warning>{∇⃗×𝐸⃗ = -∂𝐵⃗/∂t}</warning>
+   15 | e: <warning>{	42	}</warning>
      |    <warning>^~~~~~~~~~~~~~</warning>
      |    <fixit-insert>%empty</fixit-insert>
 input.y:16.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
-   16 | f: <warning>{	42	}</warning>
+   16 | f: <warning>{	"฿¥$€₦"	}</warning>
      |    <warning>^~~~~~~~~~~~~~</warning>
      |    <fixit-insert>%empty</fixit-insert>
 input.y:17.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
-   17 | g: <warning>{	"฿¥$€₦"	}</warning>
-      |    <warning>^~~~~~~~~~~~~~</warning>
-      |    <fixit-insert>%empty</fixit-insert>
-input.y:18.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
-   18 | h: <warning>{	🐃	}</warning>
+   17 | g: <warning>{	🐃	}</warning>
      |    <warning>^~~~~~~~~~~~~~</warning>
      |    <fixit-insert>%empty</fixit-insert>
 input.y: <warning>warning:</warning> fix-its can be applied.  Rerun with option '--update'. [<warning>-Wother</warning>]
 ]])


+# Likewise, but currently not portable to AIX and Cygwin.
+# https://lists.gnu.org/r/bug-bison/2020-05/msg00050.html
+# https://lists.gnu.org/r/bug-bison/2020-05/msg00003.html.
+AT_TEST([[Tabulations and multibyte characters]],
+[[%%
+e: {∇⃗×𝐸⃗ = -∂𝐵⃗/∂t}
+]],
+[0],
+[[input.y:10.4-17: <warning>warning:</warning> empty rule without %empty [<warning>-Wempty-rule</warning>]
+   10 | e: <warning>{∇⃗×𝐸⃗ = -∂𝐵⃗/∂t}</warning>
+      |    <warning>^~~~~~~~~~~~~~</warning>
+      |    <fixit-insert>%empty</fixit-insert>
+input.y: <warning>warning:</warning> fix-its can be applied.  Rerun with option '--update'. [<warning>-Wother</warning>]
+]], [], [uname -a | $EGREP -i 'aix|cygwin'])
+
+
 ## --------------- ##
 ## Special files.  ##
 ## --------------- ##
@@ -35,14 +35,9 @@ dnl time comes, just use sed to drop the line numbers.  For now, as LR(1)
 dnl support is rapidly evolving, let's keep that information to be careful.
 dnl However, we don't do diffs for canonical LR(1) because the diff is huge.
 m4_pushdef([AT_LALR1_DIFF_CHECK],
-[dnl We need diff -u, which is not portable.
-AT_CHECK([diff -u /dev/null /dev/null || exit 77], [0], [ignore])
-
-AT_CHECK([[sed 's/^%define lr.type .*$//' input.y > input-lalr.y]])
+[AT_CHECK([[sed 's/^%define lr.type .*$//' input.y > input-lalr.y]])
 AT_BISON_CHECK([[--report=all input-lalr.y]], [[0]], [ignore], [ignore])
-AT_CHECK([[diff -u input-lalr.output input.output \
-           | sed -n '/^@@/,$p' | sed 's/^ $//']],
-         [[0]], [$1])])
+AT_DIFF_U_CHECK([[input-lalr.output input.output]], [$1])])

 AT_TEST_TABLES_AND_PARSE([$2[: LALR(1)]], [[LALR]], [[last-state]],
                         [[%define lr.type lalr
@@ -323,7 +323,7 @@ AT_PERL_CHECK([[-n -0777 -e '
      |YYChar
      |YYNTOKENS  # This is actual scoped in a C++ class.
      |YYPUSH_MORE(?:_DEFINED)?
-      |S_(YY(ACCEPT|EMPTY|EOF|ERROR|UNDEF))  # These guys are scoped.
+      |S_(YY(ACCEPT|EMPTY|EOF|error|UNDEF))  # These guys are scoped.
      |YYUSE
      |YY_ATTRIBUTE(?:_PURE|_UNUSED)
      |YY(?:_REINTERPRET)?_CAST
@@ -102,7 +102,6 @@ input.y:6.1-17: error: invalid directive: '%a-does-not-exist'
 input.y:7.1: error: invalid character: '%'
 input.y:7.2: error: invalid character: '-'
 input.y:8.1-9.0: error: missing '%}' at end of file
-input.y:8.1-9.0: error: unexpected %{...%}
 ]])

 AT_CLEANUP
@@ -343,9 +342,9 @@ exp:
 %%
 int main (void)
 {
-  assert (YYERRCODE == 123);
+  assert (YYerror == 123);
  assert (YYTRANSLATE (YYEOF) == YYSYMBOL_YYEOF);
-  assert (YYTRANSLATE (YYERRCODE) == YYSYMBOL_YYERROR);
+  assert (YYTRANSLATE (YYerror) == YYSYMBOL_YYerror);
  assert (YYTRANSLATE (YYUNDEF) == YYSYMBOL_YYUNDEF);
  return 0;
 }
@@ -432,7 +431,7 @@ AT_BISON_CHECK([-Wno-other -S./dump-symbols.m4 input.y])
 AT_CHECK([cat symbols.csv], [],
 [[number, class, tag, id, user_number, type,
 0, Token, "end of file", YYEOF, 0, ,
-1, Token, error, YYERRCODE, 256, ,
+1, Token, error, YYerror, 256, ,
 2, Token, "invalid token", YYUNDEF, 257, ,
 3, Token, 'a', , 97, ,
 4, Token, "A1", A1, 1, ,
@@ -1353,8 +1352,20 @@ AT_BISON_CHECK([-fcaret  input.y], [1], [],
 ]])


+# Clang chokes on some of our comments, because it tries to "parse"
+# some documentation directives in the comments:
+#
+# input.c:166:50: error: '\a' command does not have a valid word argument [-Werror,-Wdocumentation]
+#     FAKE = 258                     /* "fake [] \a\b\f\n\r\t\v\"'?\\[\\ ??!??'??(??)??-??/??<??=??> \001\001"  */
+#                                                ~~^
 AT_DATA_GRAMMAR([input.y],
-[[%{
+[[%code requires {
+#if defined __clang__ && 10 <= __clang_major__
+# pragma clang diagnostic ignored "-Wdocumentation"
+#endif
+}
+
+%{
 /* This is seen in GCC: a %{ and %} in middle of a comment. */
 const char *foo = "So %{ and %} can be here too.";

@@ -1425,6 +1436,11 @@ char quote[] = "@:>@@:>@,";
 /* Exercise quotes in strings.  */
 %token FAKE "fake @<:@@:>@ \a\b\f\n\r\t\v\"\'\?\\\u005B\U0000005c ??!??'??(??)??-??/??<??=??> \x1\1"

+/* Beware of the generated comments that embed string aliases that
+   might close the comment.  */
+%token COMMENT_CLOSE "*/"
+%token COMMENT       "/* comment */"
+
 %%
 /* Exercise M4 quoting: '@:>@@:>@', @<:@, 1.  */
 exp: '@<:@' '\1' two '$' '@' '{' oline output.or.oline.opt
@@ -2339,19 +2355,19 @@ start: '
 start: ']])

 AT_BISON_CHECK([-fcaret empty.y], [1], [],
-[[empty.y:2.8-9: warning: empty character literal [-Wother]
+[[empty.y:2.8-9: error: empty character literal
    2 | start: '';
      |        ^~
 empty.y:3.8-4.0: error: missing "'" at end of line
    3 | start: '
      |        ^
-empty.y:3.8-4.0: warning: empty character literal [-Wother]
+empty.y:3.8-4.0: error: empty character literal
    3 | start: '
      |        ^
 empty.y:4.8: error: missing "'" at end of file
    4 | start: '
      |        ^
-empty.y:4.8: warning: empty character literal [-Wother]
+empty.y:4.8: error: empty character literal
    4 | start: '
      |        ^
 ]])
@@ -2363,11 +2379,11 @@ start: 'ab
 start: 'ab]])

 AT_BISON_CHECK([two.y], [1], [],
-[[two.y:2.8-11: warning: extra characters in character literal [-Wother]
+[[two.y:2.8-11: error: extra characters in character literal
 two.y:3.8-4.0: error: missing "'" at end of line
-two.y:3.8-4.0: warning: extra characters in character literal [-Wother]
+two.y:3.8-4.0: error: extra characters in character literal
 two.y:4.8-10: error: missing "'" at end of file
-two.y:4.8-10: warning: extra characters in character literal [-Wother]
+two.y:4.8-10: error: extra characters in character literal
 ]])

 AT_DATA_NO_FINAL_EOL([three.y],
@@ -2377,11 +2393,11 @@ start: 'abc
 start: 'abc]])

 AT_BISON_CHECK([three.y], [1], [],
-[[three.y:2.8-12: warning: extra characters in character literal [-Wother]
+[[three.y:2.8-12: error: extra characters in character literal
 three.y:3.8-4.0: error: missing "'" at end of line
-three.y:3.8-4.0: warning: extra characters in character literal [-Wother]
+three.y:3.8-4.0: error: extra characters in character literal
 three.y:4.8-11: error: missing "'" at end of file
-three.y:4.8-11: warning: extra characters in character literal [-Wother]
+three.y:4.8-11: error: extra characters in character literal
 ]])

 AT_CLEANUP
@@ -2408,25 +2424,15 @@ AT_PERL_REQUIRE([[-e 'print "start: \"\\\t\\\f\\\0\\\1\" ;";' >> input.y]])

 AT_BISON_CHECK([input.y], [1], [],
 [[input.y:2.9-12: error: invalid number after \-escape: 777
-input.y:2.8-13: warning: empty character literal [-Wother]
 input.y:2.16-17: error: invalid number after \-escape: 0
-input.y:2.15-18: warning: empty character literal [-Wother]
 input.y:2.21-25: error: invalid number after \-escape: xfff
-input.y:2.20-26: warning: empty character literal [-Wother]
 input.y:2.29-31: error: invalid number after \-escape: x0
-input.y:2.28-32: warning: empty character literal [-Wother]
 input.y:3.9-14: error: invalid number after \-escape: uffff
-input.y:3.8-15: warning: empty character literal [-Wother]
 input.y:3.18-23: error: invalid number after \-escape: u0000
-input.y:3.17-24: warning: empty character literal [-Wother]
 input.y:3.27-36: error: invalid number after \-escape: Uffffffff
-input.y:3.26-37: warning: empty character literal [-Wother]
 input.y:3.40-49: error: invalid number after \-escape: U00000000
-input.y:3.39-50: warning: empty character literal [-Wother]
 input.y:4.9-10: error: invalid character after \-escape: ' '
-input.y:4.8-11: warning: empty character literal [-Wother]
 input.y:4.14-15: error: invalid character after \-escape: A
-input.y:4.13-16: warning: empty character literal [-Wother]
 input.y:5.9-16: error: invalid character after \-escape: \t
 input.y:5.17: error: invalid character after \-escape: \f
 input.y:5.18: error: invalid character after \-escape: \0
@@ -18,9 +18,9 @@
 AT_BANNER([[Java Calculator.]])


-# ------------------------- #
-# Java invalid directives.  #
-# ------------------------- #
+## ------------------------- ##
+## Java invalid directives.  ##
+## ------------------------- ##

 AT_SETUP([Java invalid directives])

@@ -42,9 +42,9 @@ YYParser.y:4.13-30: error: %destructor does not make sense in Java
 AT_CLEANUP


-# ------------------------- #
-# Helping Autotest macros.  #
-# ------------------------- #
+## ------------------------- ##
+## Helping Autotest macros.  ##
+## ------------------------- ##


 # AT_JAVA_POSITION_DEFINE_OLD
@@ -91,9 +91,9 @@ m4_define([AT_JAVA_POSITION_DEFINE_OLD],



-# -----------------#
-# Java Parameters. #
-# -----------------#
+## ----------------- ##
+## Java Parameters.  ##
+## ----------------- ##

 AT_BANNER([Java Parameters.])

@@ -146,7 +146,7 @@ m4_define([AT_CHECK_JAVA_MINIMAL_W_LEXER],
    System.err.println (loc + ": " + s);
  }

-  public int yylex ()$2
+  public int yylex()$2
  {
    $3
  }
@@ -164,9 +164,9 @@ m4_define([AT_CHECK_JAVA_GREP],
 ])])


-# ------------------------------------- #
-# Java parser class and package names.  #
-# ------------------------------------- #
+## ------------------------------------- ##
+## Java parser class and package names.  ##
+## ------------------------------------- ##

 AT_SETUP([Java parser class and package names])

@@ -191,9 +191,9 @@ AT_CHECK_JAVA_GREP([[package user_java_package;]])
 AT_CLEANUP


-# ----------------------------- #
-# Java parser class modifiers.  #
-# ----------------------------- #
+## ----------------------------- ##
+## Java parser class modifiers.  ##
+## ----------------------------- ##

 AT_SETUP([Java parser class modifiers])

@@ -255,9 +255,9 @@ AT_CHECK_JAVA_GREP([[/\*@Deprecated @SuppressWarnings("unchecked") @SuppressWarn
 AT_CLEANUP


-# ---------------------------------------- #
-# Java parser class extends and implements #
-# ---------------------------------------- #
+## ---------------------------------------- ##
+## Java parser class extends and implements ##
+## ---------------------------------------- ##

 AT_SETUP([Java parser class extends and implements])

@@ -275,9 +275,9 @@ AT_CHECK_JAVA_GREP([[class YYParser extends Thread implements Cloneable]])
 AT_CLEANUP


-# -------------------------------- #
-# Java %parse-param and %lex-param #
-# -------------------------------- #
+## -------------------------------- ##
+## Java %parse-param and %lex-param ##
+## -------------------------------- ##

 AT_SETUP([Java %parse-param and %lex-param])

@@ -349,9 +349,9 @@ AT_CHECK_JAVA_GREP([[ *this.parse_param2 = parse_param2;]], [2])
 AT_CLEANUP


-# ------------------------- #
-# Java throw specifications #
-# ------------------------- #
+## --------------------------- ##
+## Java throw specifications.  ##
+## --------------------------- ##

 AT_SETUP([Java throws specifications])

@@ -430,17 +430,17 @@ AT_JT_initial_action],
 [AT_JT_yylex_action],
 [],
 [AT_JT_parse_action])])
-AT_CHECK_JAVA_GREP([[ *int yylex ()]AT_JT_yylex_throws *[;]])
-AT_CHECK_JAVA_GREP([[ *private int yyaction ([^)]*)]AT_JT_yyaction_throws[ *]])
-AT_CHECK_JAVA_GREP([[ *public boolean parse ()]AT_JT_parse_throws[ *]])
+AT_CHECK_JAVA_GREP([[ *int yylex()]AT_JT_yylex_throws *[;]])
+AT_CHECK_JAVA_GREP([[ *private int yyaction([^)]*)]AT_JT_yyaction_throws[ *]])
+AT_CHECK_JAVA_GREP([[ *public boolean parse()]AT_JT_parse_throws[ *]])
 ])])])

 AT_CLEANUP


-# ------------------------------------- #
-# Java constructor init and init_throws #
-# ------------------------------------- #
+## --------------------------------------- ##
+## Java constructor init and init_throws.  ##
+## --------------------------------------- ##

 AT_SETUP([Java constructor init and init_throws])

@@ -465,9 +465,9 @@ m4_popdef([AT_Witness])
 AT_CLEANUP


-# ------------------------------------------ #
-# Java value, position, and location types.  #
-# ------------------------------------------ #
+## ------------------------------------------ ##
+## Java value, position, and location types.  ##
+## ------------------------------------------ ##

 AT_SETUP([Java value, position, and location types])

@@ -496,9 +496,9 @@ AT_CHECK([[$EGREP -v ' */?\*' YYParser.java | grep -w 'Location']], [1], [ignore
 AT_CLEANUP


-# ----------------------------------------------- #
-# Java syntax error handling without error token. #
-# ----------------------------------------------- #
+## ------------------------------------------------ ##
+## Java syntax error handling without error token.  ##
+## ------------------------------------------------ ##

 AT_SETUP([Java syntax error handling without error token])

@@ -180,28 +180,28 @@ AT_DATA([[input.y]],
 # Verify that the proper procedure(s) are generated for each case.
 AT_BISON_CHECK([[-Dapi.push-pull=pull -o Main.java input.y]])
 AT_CHECK_JAVA_GREP([[Main.java]],
-                   [[.*public boolean parse ().*]],
+                   [[.*public boolean parse().*]],
                   [1])
 # If BISON_USE_PUSH_FOR_PULL is set, then we have one occurrence of
 # this function, otherwise it should not be there.
 AT_CHECK_JAVA_GREP([[Main.java]],
-        [[.*public int push_parse (int yylextoken, Object yylexval).*]],
+        [[.*public int push_parse(int yylextoken, Object yylexval).*]],
        [${BISON_USE_PUSH_FOR_PULL-0}])

 AT_BISON_CHECK([[-Dapi.push-pull=both -o Main.java input.y]])
 AT_CHECK_JAVA_GREP([[Main.java]],
-                   [[.*public boolean parse ().*]],
+                   [[.*public boolean parse().*]],
                   [1])
 AT_CHECK_JAVA_GREP([[Main.java]],
-        [[.*public int push_parse (int yylextoken, Object yylexval).*]],
+        [[.*public int push_parse(int yylextoken, Object yylexval).*]],
        [1])

 AT_BISON_CHECK([[-Dapi.push-pull=push -o Main.java input.y]])
 AT_CHECK_JAVA_GREP([[Main.java]],
-                   [[.*public boolean parse ().*]],
+                   [[.*public boolean parse().*]],
                   [0])
 AT_CHECK_JAVA_GREP([[Main.java]],
-        [[.*public int push_parse (int yylextoken, Object yylexval).*]],
+        [[.*public int push_parse(int yylextoken, Object yylexval).*]],
        [1])

 AT_JAVA_COMPILE([[Main.java]])
@@ -83,6 +83,16 @@ set x `LC_ALL=C ls -l '$1'` &&
 ## ------------- ##


+# AT_DIFF_U_CHECK(DIFF-ARGS, EXPECTED-DIFF)
+# -----------------------------------------
+# If diff -u works as we expect, use it, with headers stripped.
+m4_define([AT_DIFF_U_CHECK],
+[if $DIFF_U_WORKS; then
+  AT_CHECK([diff -u $1 | sed -n '/^@@/,$p' | sed 's/^ $//'], [0], [$2])
+fi
+])
+
+
 # AT_PERL_CHECK(PERL-ARGS, ...)
 # -----------------------------
 # If Perl is available, run this test.
@@ -490,7 +500,7 @@ m4_define([AT_DATA_SOURCE_PROLOGUE],
 # The prologue that should be included in any grammar whose parser is
 # meant to be compiled.
 m4_define([AT_DATA_GRAMMAR_PROLOGUE],
-[[%code top {
+[[%code top { /* -*- ]AT_LANG[ -*- */
 ]AT_DATA_SOURCE_PROLOGUE[]dnl
 [}
 ]])
@@ -1601,7 +1611,7 @@ $9
 # (C90 and C++98) guarantee: 32767.  In that case, GCC's -pedantic
 # will issue an error.
 #
-# There is no "" around `wc` since some indent the result.
+# There is no "" around `wc` since some wc indent the result.
 m4_bmatch([$4], [%define lr.type canonical-lr],
 [if test 32767 -lt `wc -l < input.c`; then
  CFLAGS=`echo " $CFLAGS " | sed -e 's/ -pedantic / /'`
@@ -56,6 +56,7 @@ TESTSUITE_AT =                                \
  %D%/java.at                                 \
  %D%/javapush.at                             \
  %D%/local.at                                \
+  %D%/m4.at                                   \
  %D%/named-refs.at                           \
  %D%/output.at                               \
  %D%/package.m4                              \
@@ -0,0 +1,46 @@
+# Basic m4 macros.                               -*- Autotest -*-
+
+# Copyright (C) 2020 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+AT_BANNER([[M4 Macros.]])
+
+
+AT_SETUP([Generating Comments])
+
+AT_DATA([input.y],
+[%%
+exp:
+])
+
+AT_DATA([input.m4],
+[[m4@&t@_include(b4_skeletonsdir/[c.m4])
+
+b4_output_begin([output.txt])
+b4_comment([["/* () */"]])
+b4_comment([["/* (  */"]])
+b4_comment([["/*  ) */"]])
+b4_output_end([output.txt])
+]])
+
+AT_BISON_CHECK([-S ./input.m4 input.y])
+
+AT_CHECK([cat output.txt], [],
+[/* "/\* () *\/"  */
+/* "/\* (  *\/"  */
+/* "/\*  ) *\/"  */
+])
+
+AT_CLEANUP
@@ -372,8 +372,19 @@ m4_pushdef([AT_TEST],

 AT_BISON_OPTION_PUSHDEFS([$1])

+
+# Clang chokes on some of our comments, because it tries to "parse"
+# some documentation directives in the comments:
+#
+# input.c:131:48: error: '\a' command does not have a valid word argument [-Werror,-Wdocumentation]
+#     SPECIAL = 261                  /* "\\'?\"\a\b\f\n\r\t\v\001\201\001\201??!"  */
+#                                              ~~^
 AT_DATA_GRAMMAR([input.y],
 [%{
+#if defined __clang__ && 10 <= __clang_major__
+# pragma clang diagnostic ignored "-Wdocumentation"
+#endif
+
 ]AT_YYERROR_DECLARE[
 ]AT_YYLEX_DECLARE[
 %}
@@ -398,14 +409,14 @@ exp: ]AT_ERROR_VERBOSE_IF(["\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"], ["
 # C-string literal.  Also notice that unnecessary escaping, such as "\?", from
 # the user specification is eliminated.
 AT_BISON_CHECK([-fcaret -o input.c input.y], [[0]], [[]],
-[[input.y:22.8-14: warning: symbol SPECIAL redeclared [-Wother]
-   22 | %token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
+[[input.y:26.8-14: warning: symbol SPECIAL redeclared [-Wother]
+   26 | %token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
      |        ^~~~~~~
-input.y:21.8-14: note: previous declaration
-   21 | %token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
+input.y:25.8-14: note: previous declaration
+   25 | %token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
      |        ^~~~~~~
-input.y:22.16-63: warning: symbol "\\'?\"\a\b\f\n\r\t\v\001\201\001\201??!" used more than once as a literal string [-Wother]
-   22 | %token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
+input.y:26.16-63: warning: symbol "\\'?\"\a\b\f\n\r\t\v\001\201\001\201??!" used more than once as a literal string [-Wother]
+   26 | %token SPECIAL "\\\'\?\"\a\b\f\n\r\t\v\001\201\x001\x000081??!"
      |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 ]])

@@ -16,6 +16,8 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.

+# Basic M4 macros.
+m4_include([m4.at])

 # Resistance to user bugs.
 m4_include([input.at])
@@ -1 +1 @@
 .5.4
 .6.1