version 3.6.4

* NEWS: Record release date.
glr.cc: don't leak glr.c/glr.cc scaffolding to the user
2026-08-08 18:25:13 +00:00 · 2020-06-15 20:18:50 +02:00 · 2020-06-15 20:18:47 +02:00 · 2020-06-03 07:52:30 +02:00 · 2020-06-03 07:31:43 +02:00 · 2020-06-01 08:29:53 +02:00
74 changed files with 1477 additions and 761 deletions
@@ -1 +1 @@
-3.5.90
+3.6.3
@@ -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 $<
@@ -1,27 +1,49 @@
 GNU Bison NEWS

-* Noteworthy changes in release 3.5.91 (2020-04-29) [stable]
+* Noteworthy changes in release 3.6.4 (2020-06-15) [stable]
+
+** Bug fixes
+
+  In glr.cc some internal macros leaked in the user's code, and could damage
+  access to the token kinds.
+
+* Noteworthy changes in release 3.6.3 (2020-06-03) [stable]
+
+** Bug fixes
+
+  Incorrect comments in the generated parsers.
+
+  Warnings in push parsers (yacc.c).
+
+  Incorrect display of gotos in LAC traces (lalr1.cc).
+
+* 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

-*** Returning the error token
+  In C++, yy::parser::symbol_type now has a public name() member function.

-  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.
-
-*** The bistromathic features internationalization
-
-  Its way to build the error message is more general and is easy to use in
-  other projects.
-
-* Noteworthy changes in release 3.5.90 (2020-04-18) [beta]
+* Noteworthy changes in release 3.6 (2020-05-08) [stable]

 ** Backward incompatible changes

@@ -126,6 +148,18 @@ 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
@@ -213,8 +247,8 @@ 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.
@@ -2545,7 +2579,7 @@ 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:

@@ -2900,7 +2934,7 @@ 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.
@@ -2920,7 +2954,7 @@ 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,
@@ -3014,7 +3048,7 @@ 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.
@@ -3039,7 +3073,7 @@ 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.

@@ -3054,7 +3088,7 @@ 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:
@@ -3240,7 +3274,7 @@ 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.
@@ -3354,7 +3388,7 @@ 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.
@@ -3362,7 +3396,7 @@ 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
@@ -3444,7 +3478,7 @@ 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.

@@ -3470,7 +3504,7 @@ 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

@@ -3533,7 +3567,7 @@ 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.
@@ -3653,7 +3687,7 @@ 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.

@@ -3684,7 +3718,7 @@ 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
@@ -3828,7 +3862,7 @@ 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
@@ -3843,7 +3877,7 @@ 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
@@ -3863,7 +3897,7 @@ 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
@@ -3872,7 +3906,7 @@ 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

@@ -3880,7 +3914,7 @@ 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

@@ -3967,7 +4001,7 @@ 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
@@ -3978,7 +4012,7 @@ 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
@@ -4013,7 +4047,7 @@ 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.

@@ -4023,12 +4057,12 @@ 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.

@@ -4045,7 +4079,7 @@ 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.
@@ -4070,7 +4104,7 @@ 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
@@ -4079,11 +4113,11 @@ 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++.

@@ -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]
@@ -154,11 +156,13 @@ 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]
 Raja R Harinath           [email protected]
 Ralf Wildenhues           [email protected]
+Ryan                      [email protected]
 Rich Wilson               [email protected]
 Richard Stallman          [email protected]
 Rici Lake                 [email protected]
@@ -1,4 +1,18 @@
-* Bison 3.6
+* Bison 3.7
+** glr.cc
+Get rid of global_tokens_and_yystype.
+
+** 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
@@ -25,13 +39,9 @@ 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).

-* Bison 3.7
 ** Counter example generation
 See https://github.com/akimd/bison/pull/15.

@@ -71,8 +81,79 @@ 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.

+** %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:
+
+    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");
+        }
+    }
+
+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.
+
+If we want to do that, we should think very carefully about the syntax of
+the format string.
+
+** 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
+** Rewrite glr.cc
+Get rid of scaffolding in glr.c.
+
 ** Unit rules / Injection rules (Akim Demaille)
 Maybe we could expand unit rules (or "injections", see
 https://homepages.cwi.nl/~daybuild/daily-books/syntax/2-sdf/sdf.html), i.e.,
@@ -146,10 +227,10 @@ 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
@@ -353,8 +434,12 @@ 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
@@ -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
@@ -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]), [[-_]],
@@ -137,7 +135,9 @@ if test "$enable_gcc_warnings" = yes; then
    -Wpointer-arith -Wshadow
    -Wwrite-strings
    -wr188 -wr2259 -wr3179'
-  warn_c='-Wbad-function-cast -Wstrict-prototypes'
+  warn_c='-Wbad-function-cast
+    -Wmissing-prototypes
+    -Wstrict-prototypes'
  warn_cxx='-Wextra-semi -Wnoexcept -Wold-style-cast -Wundefined-func-template
    -Wweak-vtables'
  # Warnings for the test suite only.
@@ -261,9 +261,9 @@ if ! "$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 $bison_cv_cxx_works = yes])
 AC_PROG_YACC
 AC_PROG_RANLIB
 AC_PROG_GNU_M4
@@ -332,6 +332,13 @@ AC_MSG_RESULT([$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])
@@ -34,6 +34,7 @@ dist_skeletons_DATA =                           \
  data/skeletons/lalr1.java                     \
  data/skeletons/location.cc                    \
  data/skeletons/stack.hh                       \
+  data/skeletons/traceon.m4                     \
  data/skeletons/variant.hh                     \
  data/skeletons/yacc.c

@@ -19,6 +19,27 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.


+
+# m4_gsub(STRING, RE1, SUBST1, RE2, SUBST2, ...)
+# ----------------------------------------------
+# m4 equivalent of
+#
+#   $_ = STRING;
+#   s/RE1/SUBST1/g;
+#   s/RE2/SUBST2/g;
+#   ...
+#
+# Really similar to m4_bpatsubsts, but behaves properly with quotes.
+# See m4.at's "Generating Comments".  Super inelegant, but so far, I
+# did not find any better solution.
+m4_define([b4_gsub],
+[m4_bpatsubst(m4_bpatsubst(m4_bpatsubst([[[[$1]]]],
+                                        [$2], [$3]),
+                           [$4], [$5]),
+              [$6], [$7])])
+
+
+
 ## ---------------- ##
 ## Identification.  ##
 ## ---------------- ##
@@ -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.
@@ -357,7 +357,30 @@ m4_define([b4_symbol_type_define],
        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.
@@ -409,11 +432,17 @@ m4_define([b4_symbol_type_define],
      /// \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 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_kind>
    {]b4_variant_if([[
@@ -531,6 +560,12 @@ m4_define([b4_public_types_define],
  {
    return kind_;
  }
+
+  ]b4_inline([$1])[]b4_parser_class[::symbol_kind_type
+  ]b4_parser_class[::by_kind::type_get () const YY_NOEXCEPT
+  {
+    return this->kind ();
+  }
 ]])


@@ -17,15 +17,21 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.

+
 # _b4_comment(TEXT, OPEN, CONTINUE, END)
 # --------------------------------------
 # 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[]b4_gsub(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
@@ -230,7 +230,9 @@ b4_copyright([Skeleton implementation for Bison GLR parsers in C],

 ]b4_defines_if([[#include "@basename(]b4_spec_header_file[@)"]],
               [b4_shared_declarations])[
-]b4_declare_symbol_enum[
+
+]b4_glr_cc_if([b4_glr_cc_setup],
+              [b4_declare_symbol_enum])[

 /* Default (constant) value used for initialization for null
   right-hand sides.  Unlike the standard yacc.c template, here we set
@@ -249,6 +251,7 @@ 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
@@ -277,9 +280,6 @@ 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
@@ -507,7 +507,7 @@ 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
@@ -527,8 +527,8 @@ 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 {
@@ -568,7 +568,7 @@ struct yyGLRStack {
  YYJMP_BUF yyexception_buffer;
  yyGLRStackItem* yyitems;
  yyGLRStackItem* yynextFree;
-  ptrdiff_t yyspaceLeft;
+  YYPTRDIFF_T yyspaceLeft;
  yyGLRState* yysplitPoint;
  yyGLRState* yylastDeleted;
  yyGLRStateSet yytops;
@@ -680,7 +680,7 @@ 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;
@@ -696,7 +696,7 @@ 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(
@@ -731,12 +731,12 @@ 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 (;;)
@@ -1104,7 +1104,7 @@ 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 =
@@ -1136,14 +1136,14 @@ 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)
    {
@@ -1152,7 +1152,7 @@ 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;
 }

@@ -1165,14 +1165,14 @@ 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;
@@ -1198,9 +1198,9 @@ 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;
@@ -1208,7 +1208,7 @@ 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);
@@ -1273,7 +1273,7 @@ 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];
@@ -1297,7 +1297,7 @@ 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)
    {
@@ -1330,8 +1330,8 @@ 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;
@@ -1351,8 +1351,8 @@ 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);
@@ -1382,7 +1382,7 @@ 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([
@@ -1415,7 +1415,7 @@ 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);
@@ -1467,10 +1467,10 @@ 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)
    {
@@ -1492,7 +1492,7 @@ 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;
@@ -1534,8 +1534,8 @@ 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)
    {
@@ -1544,8 +1544,8 @@ 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;
@@ -1554,7 +1554,7 @@ 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);
@@ -1565,7 +1565,7 @@ 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);
@@ -1996,8 +1996,8 @@ 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)
    {
@@ -2040,7 +2040,7 @@ yyprocessOneStack (yyGLRStack* yystackp, ptrdiff_t yyk,
          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,
@@ -2121,6 +2121,8 @@ 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;
 }]])[

@@ -2228,7 +2230,7 @@ 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
@@ -2259,11 +2261,11 @@ 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;
@@ -2271,7 +2273,7 @@ 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)
    {
@@ -2348,7 +2350,7 @@ 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;
@@ -2423,7 +2425,7 @@ 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"));

@@ -2505,7 +2507,7 @@ b4_dollar_popdef])[]dnl
      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)[;
@@ -2612,8 +2614,8 @@ 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])
              {
@@ -2660,7 +2662,7 @@ yypstates (yyGLRState* yyst)
 }

 static void
-yypstack (yyGLRStack* yystackp, ptrdiff_t yyk)
+yypstack (yyGLRStack* yystackp, YYPTRDIFF_T yyk)
 {
  yypstates (yystackp->yytops.yystates[yyk]);
 }
@@ -2705,7 +2707,7 @@ 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])));
@@ -2731,7 +2733,7 @@ m4_if(b4_prefix, [yy], [],
 #define yynerrs ]b4_prefix[nerrs]b4_locations_if([[
 #define yylloc  ]b4_prefix[lloc]])])[

-]m4_ifdef([b4_pre_epilogue], [b4_pre_epilogue])[]dnl This is a hack for glr.cc.  To remove when we have a better glr.cc.
-b4_percent_code_get([[epilogue]])[]dnl
+]b4_glr_cc_if([b4_glr_cc_cleanup])[
+]b4_percent_code_get([[epilogue]])[]dnl
 b4_epilogue[]dnl
 b4_output_end
@@ -105,12 +105,6 @@ yyerror (]b4_locations_if([[const ]b4_namespace_ref::b4_parser_class[::location_
         ]])[]m4_ifset([b4_parse_param], [b4_formals(b4_parse_param),
         ])[const char* msg);]])[

-]b4_percent_define_flag_if([[global_tokens_and_yystype]], [],
-[m4_define([b4_pre_epilogue],
-[[/* The user is using the C++ token kind, not the C one. */
-#undef ]b4_symbol(0, [id])
-])])[
-
 # Hijack the epilogue to define implementations (yyerror, parser member
 # functions etc.).
 ]m4_append([b4_epilogue],
@@ -222,6 +216,53 @@ b4_namespace_close[]dnl
 ])


+# b4_glr_cc_setup
+# ---------------
+# Setup redirections for glr.c: Map the names used in c.m4 to the ones used
+# in c++.m4.
+m4_define([b4_glr_cc_setup],
+[[#undef ]b4_symbol(-2, [id])[
+#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
+#endif
+#ifndef ]b4_api_PREFIX[LTYPE
+# define ]b4_api_PREFIX[LTYPE ]b4_namespace_ref[::]b4_parser_class[::location_type
+#endif
+
+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
+]])
+
+
+# b4_glr_cc_cleanup
+# -----------------
+# Remove redirections for glr.c.
+m4_define([b4_glr_cc_cleanup],
+[b4_percent_define_flag_if([[global_tokens_and_yystype]], [],
+[[#undef ]b4_symbol(-2, [id])[
+#undef ]b4_symbol(0, [id])[
+#undef ]b4_symbol(1, [id])[
+]])[
+
+#undef ]b4_api_PREFIX[STYPE
+#undef ]b4_api_PREFIX[LTYPE
+
+#undef ]b4_symbol_prefix[YYEMPTY
+#undef ]b4_symbol_prefix[YYerror
+#undef ]b4_symbol_prefix[YYEOF
+#undef ]b4_symbol_prefix[YYUNDEF
+]])
+
+
 # b4_shared_declarations(hh|cc)
 # -----------------------------
 # Declaration that might either go into the header (if --defines, $1 = hh)
@@ -339,33 +380,11 @@ b4_percent_define_flag_if([[global_tokens_and_yystype]],
 ])[
 ]b4_namespace_close[

-]dnl Map the name used in c.m4 to the one used in c++.m4.
-[#undef ]b4_symbol(-2, [id])[
-#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
-#endif
-#ifndef ]b4_api_PREFIX[LTYPE
-# define ]b4_api_PREFIX[LTYPE ]b4_namespace_ref[::]b4_parser_class[::location_type
-#endif
-
-]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
-]])[
 ]b4_percent_code_get([[provides]])[
 ]m4_popdef([b4_parse_param])dnl
-])
+])[

-b4_defines_if(
+]b4_defines_if(
 [b4_output_begin([b4_spec_header_file])
 b4_copyright([Skeleton interface for Bison GLR parsers in C++],
             [2002-2015, 2018-2020])[
@@ -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;
@@ -307,26 +334,14 @@ m4_define([b4_shared_declarations],
    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);]],
 [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);
-
    /// For a symbol, its name in clear.
    static const char* const yytname_[];
 #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);
-
-    /// Convert the symbol name \a n to a form suitable for a diagnostic.
+[[    /// 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.
@@ -464,6 +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])[
@@ -597,83 +613,6 @@ m4_if(b4_prefix, [yy], [],
 #define YYRECOVERING()  (!!yyerrstatus_)

 ]b4_namespace_open[
-]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]);
-  }
-]])[
-
  /// Build a parser object.
  ]b4_parser_class::b4_parser_class[ (]b4_parse_param_decl[)
 #if ]b4_api_PREFIX[DEBUG
@@ -805,7 +744,7 @@ m4_if(b4_prefix, [yy], [],
      {
        symbol_kind_type yykind = yysym.kind ();
        yyo << (yykind < YYNTOKENS ? "token" : "nterm")
-            << ' ' << symbol_name (yykind) << " ("]b4_locations_if([
+            << ' ' << yysym.name () << " ("]b4_locations_if([
            << yysym.location << ": "])[;
        ]b4_symbol_actions([printer])[
        yyo << ')';
@@ -1257,8 +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)
@@ -1316,6 +1333,8 @@ b4_dollar_popdef])[]dnl
            }
      }
 ]])[
+    if (yyarg && yycount == 0 && 0 < yyargn)
+      yyarg[0] = symbol_kind::]b4_symbol(-2, kind)[;
    return yycount;
  }

@@ -1392,7 +1411,7 @@ b4_dollar_popdef])[]dnl
                     : yylac_stack_.back ());
        // Push the resulting state of the reduction.
        state_type state = yy_lr_goto_state_ (top_state, yyr1_[yyrule]);
-        YYCDEBUG << " G" << state;
+        YYCDEBUG << " G" << int (state);
        yylac_stack_.push_back (state);
      }
  }
@@ -121,7 +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.
     */
@@ -182,25 +182,24 @@ import java.text.MessageFormat;
 ]b4_token_enums[
    /** 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
@@ -208,24 +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);
 ]])[
  }

@@ -307,9 +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([[
  /**
@@ -317,9 +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);
  }

  /**
@@ -327,9 +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) {
@@ -469,7 +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.
@@ -477,10 +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)
      {
@@ -488,13 +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;
  }

@@ -504,13 +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([],[[
@@ -521,7 +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
@@ -532,7 +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;]])[
@@ -612,8 +610,8 @@ 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 (yytoken == SymbolKind.]b4_symbol_prefix[YYerror)
          {
@@ -649,8 +647,8 @@ b4_dollar_popdef[]dnl
            else
              {
                /* Shift the lookahead token.  */]b4_parse_trace_if([[
-                yySymbolPrint ("Shifting", yytoken,
-                               yylval]b4_locations_if([, yylloc])[);
+                yySymbolPrint("Shifting", yytoken,
+                              yylval]b4_locations_if([, yylloc])[);
 ]])[
                /* Discard the token being shifted.  */
                yychar = YYEMPTY_;
@@ -683,7 +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;

@@ -781,8 +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])[);
@@ -833,7 +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.
   *
@@ -843,36 +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;
  }
 ]])[

@@ -950,6 +944,8 @@ b4_dollar_popdef[]dnl
                  yyarg[yycount++] = SymbolKind.get (yyx);
              }
        }
+      if (yyarg != null && yycount == yyoffset && yyoffset < yyargn)
+        yyarg[yycount] = null;
      return yycount - yyoffset;
    }
  }
@@ -996,39 +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"])[);]])[
  }

  /**
@@ -1074,10 +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_;
    };
@@ -0,0 +1,2 @@
+dnl GNU M4 treats -dV in a position-independent manner.
+m4_debugmode(V)m4_traceon()dnl
@@ -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])@})])

@@ -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;
@@ -826,9 +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");
    }
 }
@@ -1197,6 +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;
 }

@@ -1517,7 +1480,7 @@ yypull_parse (yypstate *yyps]b4_user_formals[)
 ]b4_parse_state_variable_macros([b4_pstate_macro_define])[

 /* Initialize the parser data structure.  */
-void
+static void
 yypstate_clear (yypstate *yyps)
 {
 ]b4_initialize_parser_state_variables[
@@ -2016,7 +1979,7 @@ 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];
@@ -2052,10 +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.
@@ -1882,6 +1879,7 @@ Here is the code for the lexical analyzer:
   and tabs, and returns 0 for end-of-input. */

 #include <ctype.h>
+#include <stdlib.h>
@end group

@group
@@ -1898,7 +1896,8 @@ yylex (void)
  if (c == '.' || isdigit (c))
    @{
      ungetc (c, stdin);
-      scanf ("%lf", &yylval);
+      if (scanf ("%lf", &yylval) != 1)
+        abort ();
      return NUM;
    @}
@end group
@@ -2369,9 +2368,9 @@ 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
@@ -2731,7 +2730,8 @@ yylex (void)
  if (c == '.' || isdigit (c))
    @{
      ungetc (c, stdin);
-      scanf ("%lf", &yylval.NUM);
+      if (scanf ("%lf", &yylval.NUM) != 1)
+        abort ();
      return NUM;
    @}
@end group
@@ -2758,10 +2758,10 @@ Bison generated a definition of @code{YYSTYPE} with a member named
          if (bufsize <= i)
            @{
              bufsize = 2 * bufsize + 40;
-              symbuf = realloc (symbuf, bufsize);
+              symbuf = realloc (symbuf, (size_t) bufsize);
            @}
          /* Add this character to the buffer. */
-          symbuf[i++] = c;
+          symbuf[i++] = (char) c;
          /* Get another character. */
          c = getchar ();
        @}
@@ -4505,12 +4505,17 @@ 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
@@ -6132,7 +6137,7 @@ 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}.
@@ -6922,10 +6927,7 @@ 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.
@@ -7028,16 +7030,40 @@ 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.
@@ -7051,50 +7077,35 @@ 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}
@@ -7546,9 +7557,12 @@ Fill @var{argv} with the expected tokens, which never includes
@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
@@ -7655,11 +7669,11 @@ 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
@@ -9645,10 +9659,10 @@ 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
@@ -10604,6 +10618,26 @@ 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 (mismatch)
+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.
@@ -10997,6 +11031,7 @@ 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}}.

@@ -12111,9 +12146,10 @@ 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}.
@@ -12121,6 +12157,8 @@ 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.  This implementation is
@@ -12253,6 +12291,12 @@ 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.
@@ -13001,9 +13045,6 @@ 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.

@@ -13275,9 +13316,10 @@ 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}.
@@ -13318,9 +13360,9 @@ 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}.
@@ -13330,7 +13372,7 @@ 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.
@@ -13340,7 +13382,8 @@ 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}@}}.
@@ -14668,6 +14711,14 @@ 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}.
@@ -14717,8 +14768,8 @@ 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
@@ -14757,24 +14808,26 @@ 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
@@ -14822,6 +14875,10 @@ 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
@@ -14908,12 +14965,21 @@ 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
@@ -15206,6 +15272,7 @@ London, Department of Computer Science, TR-00-12 (December 2000).
@c LocalWords: YYUNDEF SymbolKind yypcontext YYENOMEM TOKENMAX getBundle
@c LocalWords: ResourceBundle myResources getString getName getToken
@c LocalWords: getLocation getExpectedTokens reportSyntaxError bistromathic
+@c LocalWords: TokenKind

@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
@@ -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
@@ -5,7 +5,7 @@ BASE = bistromathic
 BISON = bison
 XSLTPROC = xsltproc

-# We need to find the headers and libs for readline and intl.
+# 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
@@ -14,7 +14,7 @@ LDFLAGS = -L/opt/local/lib
 BISON_LOCALEDIR = $(shell $(BISON) $(BISON_FLAGS) --print-localedir)
 CPPFLAGS += -DENABLE_NLS -DBISON_LOCALEDIR='"$(BISON_LOCALEDIR)"'

-LIBS = -lreadline -lintl
+LIBS = -lreadline -lm # In some environments, -lintl is needed.

 all: $(BASE)

@@ -14,6 +14,9 @@ This example demonstrates best practices when using Bison.
 - 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' >/dev/null; 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
@@ -66,7 +101,7 @@ cat >input <<EOF
 EOF
 run 0 '> *
 > ''
-err: 1.1: syntax error: expected end of file or - or ( or exit or 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
@@ -227,14 +262,22 @@ err: Cleanup: popping nterm input (1.1-4: )' -p
 # 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... $(uname -s)"
+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
@@ -19,19 +19,23 @@ 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 =			\
-  -DBISON_LOCALEDIR='"$(localdir)"'		\
-  -DLOCALEDIR='"$(localdir)"'			\
-  -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
-%C%_bistromathic_LDADD = -lm -lreadline $(LIBINTL)
+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_CFLAGS = $(TEST_CFLAGS)
+  %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
@@ -2,6 +2,7 @@

 %code top {
  #include <ctype.h>  // isdigit
+  #include <locale.h> // LC_ALL
  #include <math.h>   // cos, sin, etc.
  #include <stdarg.h> // va_start
  #include <stdio.h>  // printf
@@ -216,7 +217,7 @@ getsym (char const *name)
 }

 // How many symbols are registered.
-int
+static int
 symbol_count (void)
 {
  int res = 0;
@@ -310,12 +311,12 @@ yylex (const char **line, YYSTYPE *yylval, YYLTYPE *yylloc)
 `---------*/


-const char *
+static const char *
 error_format_string (int argc)
 {
  switch (argc)
    {
-    default: /* Avoid compiler warnings. */
+    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
@@ -331,7 +332,7 @@ error_format_string (int argc)
    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");
+    case 8: return _("%@: syntax error: expected %0e or %1e or %2e or %3e or %4e or %5e etc., before %u");
    }
 }

@@ -339,12 +340,15 @@ error_format_string (int argc)
 int
 yyreport_syntax_error (const yypcontext_t *ctx)
 {
-  enum { ARGS_MAX = 7 };
+  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 char *format = error_format_string (1 + 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.
@@ -361,7 +365,7 @@ yyreport_syntax_error (const yypcontext_t *ctx)
      }
    // %0e, %1e...: expected token.
    else if (format[0] == '%'
-             && isdigit (format[1])
+             && isdigit ((unsigned char) format[1])
             && format[2] == 'e'
             && (format[1] - '0') < argsize)
      {
@@ -392,12 +396,30 @@ void yyerror (YYLTYPE *loc, char const *format, ...)
 }


+// 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);
+  if (!new)
+    abort ();
+  new[len] = '\0';
+  return memcpy (new, string, len);
+}
+
+
 /*-----------.
 | Readline.  |
 `-----------*/

 // Parse (and execute) this line.
-int process_line (YYLTYPE *lloc, const char *line)
+static int
+process_line (YYLTYPE *lloc, const char *line)
 {
  yypstate *ps = yypstate_new ();
  int status = 0;
@@ -412,7 +434,8 @@ int process_line (YYLTYPE *lloc, const char *line)
 }

 // Get the list of possible tokens after INPUT was read.
-int
+// Returns a nonnegative.
+static int
 expected_tokens (const char *input,
                 int *tokens, int ntokens)
 {
@@ -433,16 +456,18 @@ expected_tokens (const char *input,

  // Then query for the accepted tokens at this point.
  int res = yypstate_expected_tokens (ps, tokens, ntokens);
+  if (res < 0)
+    abort ();
  yypstate_delete (ps);
  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. */
-char **
+// 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.
+static char **
 completion (const char *text, int start, int end)
 {
  YYDPRINTF ((stderr, "completion (\"%.*s[%.*s]%s\")\n",
@@ -452,14 +477,17 @@ 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, (size_t) start);
  int ntokens = expected_tokens (line, tokens, YYNTOKENS);
  free (line);

  // Build MATCHES, the list of possible completions.
-  const int len = strlen (text);
+  const size_t len = strlen (text);
  // Need initial prefix and final NULL.
-  char **matches = calloc (ntokens + symbol_count () + 2, sizeof *matches);
+  char **matches
+    = calloc ((size_t) ntokens + (size_t) symbol_count () + 2, sizeof *matches);
+  if (!matches)
+    abort ();
  int match = 1;
  for (int i = 0; i < ntokens; ++i)
    switch (tokens[i])
@@ -489,12 +517,12 @@ completion (const char *text, int start, int end)
    matches[0] = strdup (text);
  else
    {
-      int lcplen = strlen (matches[1]);
+      size_t lcplen = strlen (matches[1]);
      for (int i = 2; i < match && lcplen; ++i)
-        for (int j = 0; j < lcplen; ++j)
+        for (size_t 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)
@@ -515,7 +543,8 @@ completion (const char *text, int start, int end)
  return matches;
 }

-void init_readline (void)
+static void
+init_readline (void)
 {
  // Allow conditional parsing of the ~/.inputrc file.
  rl_readline_name = "bistromathic";
@@ -534,7 +563,8 @@ void init_readline (void)
 | Main.  |
 `-------*/

-int main (int argc, char const* argv[])
+int
+main (int argc, char const* argv[])
 {
 #if defined ENABLE_NLS && ENABLE_NLS
  // Set up internationalization.
@@ -1,6 +1,7 @@
 %code top {
  #include <ctype.h>  /* isdigit. */
-  #include <stdio.h>  /* For printf, etc. */
+  #include <stdio.h>  /* printf. */
+  #include <stdlib.h> /* abort. */
  #include <string.h> /* strcmp. */

  int yylex (void);
@@ -73,7 +74,8 @@ yylex (void)
  if (c == '.' || isdigit (c))
    {
      ungetc (c, stdin);
-      scanf ("%lf", &yylval.NUM);
+      if (scanf ("%lf", &yylval.NUM) != 1)
+        abort ();
      return NUM;
    }

@@ -27,6 +27,7 @@ nodist_%C%_calc_SOURCES = %D%/calc.y

 # Don't use gnulib's system headers.
 %C%_calc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+%C%_calc_CFLAGS = $(TEST_CFLAGS)

 dist_calc_DATA = %D%/calc.y %D%/Makefile %D%/README.md
 CLEANFILES += %D%/calc.[ch] %D%/calc.output %D%/scan.c
@@ -25,6 +25,8 @@ if FLEX_WORKS
  nodist_%C%_lexcalc_SOURCES = %D%/parse.y %D%/parse.h %D%/scan.l
  # Don't use gnulib's system headers.
  %C%_lexcalc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+  # Fighting warnings triggered by Flex is just too painful.
+  # %C%_lexcalc_CFLAGS = $(TEST_CFLAGS)
 endif FLEX_WORKS

 %D%/parse.c: $(dependencies)
@@ -4,7 +4,7 @@
 %option nodefault noinput nounput noyywrap

 %{
-#include <errno.h> /* errno, ERANGE */
+#include <errno.h>  /* errno, ERANGE */
 #include <limits.h> /* INT_MIN */
 #include <stdlib.h> /* strtol */

@@ -12,7 +12,7 @@

  // Each time a rule is matched, advance the end cursor/position.
 #define YY_USER_ACTION                          \
-  yylloc->last_column += yyleng;
+  yylloc->last_column += (int) yyleng;

  // Move the first position onto the last.
 #define LOCATION_STEP()                         \
@@ -31,6 +31,7 @@ nodist_%C%_mfcalc_SOURCES = $(mfcalc_sources)
 %D%/mfcalc.c: $(dependencies)
 # Don't use gnulib's system headers.
 %C%_mfcalc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+%C%_mfcalc_CFLAGS = $(TEST_CFLAGS)
 %C%_mfcalc_LDADD = -lm

 dist_TESTS += %D%/mfcalc.test
@@ -1,7 +1,7 @@
 %code top {
  #include <ctype.h>  /* isdigit. */
-  #include <stdbool.h>
-  #include <stdio.h>  /* For printf, etc. */
+  #include <stdio.h>  /* printf. */
+  #include <stdlib.h> /* abort. */
  #include <string.h> /* strcmp. */
 }

@@ -81,7 +81,8 @@ yylex (YYSTYPE *yylval)
  if (c == '.' || isdigit (c))
    {
      ungetc (c, stdin);
-      scanf ("%lf", &yylval->NUM);
+      if (scanf ("%lf", &yylval->NUM) != 1)
+        abort ();
      return NUM;
    }

@@ -27,6 +27,7 @@ nodist_%C%_calc_SOURCES = %D%/calc.y

 # Don't use gnulib's system headers.
 %C%_calc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+%C%_calc_CFLAGS = $(TEST_CFLAGS)

 dist_pushcalc_DATA = %D%/calc.y %D%/Makefile %D%/README.md
 CLEANFILES += %D%/calc.[ch] %D%/calc.output
@@ -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
@@ -26,6 +26,8 @@ if FLEX_WORKS
  BUILT_SOURCES += $(nodist_%C%_reccalc_SOURCES)
  # Don't use gnulib's system headers.
  %C%_reccalc_CPPFLAGS = -I$(top_srcdir)/%D% -I$(top_builddir)/%D%
+  # Fighting warnings triggered by Flex is just too painful.
+  # %C%_reccalc_CFLAGS = $(TEST_CFLAGS)
 endif FLEX_WORKS

 %D%/parse.c: $(dependencies)
@@ -69,7 +71,9 @@ 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
@@ -32,9 +32,9 @@
        do                                              \
          capacity = capacity ? 2 * capacity : 128;     \
        while (capacity < size + yyleng + 1);           \
-        str = realloc (str, capacity);                  \
+        str = realloc (str, (size_t) capacity);         \
      }                                                 \
-    memcpy (str + size, yytext, yyleng);                \
+    memcpy (str + size, yytext, (size_t) yyleng);       \
    size += yyleng;                                     \
    assert (size < capacity);                           \
  } while (0)
@@ -31,6 +31,7 @@ nodist_%C%_rpcalc_SOURCES = $(rpcalc_sources)
 %D%/rpcalc.c: $(dependencies)
 # Don't use gnulib's system headers.
 %C%_rpcalc_CPPFLAGS = -I$(top_builddir)/%D%
+%C%_rpcalc_CFLAGS = $(TEST_CFLAGS)
 %C%_rpcalc_LDADD = -lm

 dist_TESTS += %D%/rpcalc.test
@@ -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");
    {
@@ -131,20 +142,33 @@ 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());
@@ -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();
@@ -35,6 +35,9 @@
 dist_noinst_SCRIPTS = %D%/extexi %D%/test
 TEST_LOG_COMPILER = $(SHELL) $(top_srcdir)/%D%/test

+TEST_CFLAGS =						\
+  $(WARN_CFLAGS) $(WARN_CFLAGS_TEST) $(WERROR_CFLAGS)
+
 AM_CXXFLAGS =							\
  $(WARN_CXXFLAGS) $(WARN_CXXFLAGS_TEST) $(WERROR_CXXFLAGS)

@@ -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=$(pwd)
@@ -34,6 +34,14 @@ cwd=$(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
+echo "checking for diff --strip-trailing-cr... $diff_opts"
+
 # The exercised program.
 abs_medir=$cwd/examples/$medir
 if test -x "$abs_medir/$me"; then
@@ -68,6 +76,20 @@ trap cleanup 0 1 2 13 15
 mkdir $$.dir
 cd $$.dir

+
+# 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.
@@ -115,7 +137,7 @@ run ()
  } >eff

  if test $sta_eff -eq $sta_exp; then
-    if cmp eff exp 2>/dev/null; then
+    if diff $diff_opts eff exp >/dev/null 2>&1; then
      echo "$me: PASS: $number"
    else
      echo "$me: FAIL: $number"
@@ -126,21 +148,21 @@ run ()
      echo "$me: effective output:"
      sed -e 's/^/  /' eff
      echo "$me: diff:"
-      diff -u exp eff | sed -e 's/^/  /'
-      exit=false
+      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
@@ -56,7 +56,6 @@
 /gnulib-comp.m4
 /gnulib-tool.m4
 /host-cpu-c-abi.m4
-/iconv.m4
 /include_next.m4
 /intdiv0.m4
 /intl.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; }
@@ -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>
@@ -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)
        {
@@ -257,7 +257,8 @@ static const argmatch_trace_doc argmatch_trace_docs[] =
  { "sets",       "grammar sets: firsts, nullable etc." },
  { "muscles",    "m4 definitions passed to the skeleton" },
  { "tools",      "m4 invocation" },
-  { "m4",         "m4 traces" },
+  { "m4-early",   "m4 traces starting from the start" },
+  { "m4",         "m4 traces starting from the skeleton evaluation" },
  { "skeleton",   "skeleton postprocessing" },
  { "time",       "time consumption" },
  { "ielr",       "IELR conversion" },
@@ -279,6 +280,7 @@ static const argmatch_trace_arg argmatch_trace_args[] =
  { "sets",      trace_sets },
  { "muscles",   trace_muscles },
  { "tools",     trace_tools },
+  { "m4-early",  trace_m4_early },
  { "m4",        trace_m4 },
  { "skeleton",  trace_skeleton },
  { "time",      trace_time },
@@ -100,11 +100,12 @@ enum trace
    trace_grammar   = 1 << 7,  /**< Reading, reducing the grammar. */
    trace_time      = 1 << 8,  /**< Time consumption. */
    trace_skeleton  = 1 << 9,  /**< Skeleton postprocessing. */
-    trace_m4        = 1 << 10, /**< M4 traces. */
-    trace_muscles   = 1 << 11, /**< M4 definitions of the muscles. */
-    trace_ielr      = 1 << 12, /**< IELR conversion. */
-    trace_closure   = 1 << 13, /**< Input/output of closure(). */
-    trace_locations = 1 << 14, /**< Full display of locations. */
+    trace_m4_early  = 1 << 10, /**< M4 early traces. */
+    trace_m4        = 1 << 11, /**< M4 traces. */
+    trace_muscles   = 1 << 12, /**< M4 definitions of the muscles. */
+    trace_ielr      = 1 << 13, /**< IELR conversion. */
+    trace_closure   = 1 << 14, /**< Input/output of closure(). */
+    trace_locations = 1 << 15, /**< Full display of locations. */
    trace_all       = ~0       /**< All of the above.  */
  };
 /** What debug items bison displays during its run.  */
@@ -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)                                \
@@ -126,8 +127,7 @@ src_bison_LDADD =                               \
  $(LIBTHREAD)                                  \
  $(LIB_CLOCK_GETTIME)                          \
  $(LIB_GETHRXTIME)                             \
-  $(LIBTEXTSTYLE)                               \
-  lib/libbison.a
+  $(LIBTEXTSTYLE)


 EXTRA_DIST += %D%/i18n-strings.c
@@ -687,6 +687,7 @@ output_skeleton (void)
  char *skeldir = xpath_join (datadir, "skeletons");
  char *m4sugar = xpath_join (datadir, "m4sugar/m4sugar.m4");
  char *m4bison = xpath_join (skeldir, "bison.m4");
+  char *traceon = xpath_join (skeldir, "traceon.m4");
  char *skel = (IS_PATH_WITH_DIR (skeleton)
                ? xstrdup (skeleton)
                : xpath_join (skeldir, skeleton));
@@ -698,21 +699,10 @@ output_skeleton (void)

  /* Create an m4 subprocess connected to us via two pipes.  */

-  if (trace_flag & trace_tools)
-    fprintf (stderr, "running: %s %s - %s %s\n",
-             m4, m4sugar, m4bison, skel);
-
-  /* Some future version of GNU M4 (most likely 1.6) may treat the -dV in a
-     position-dependent manner.  Keep it as the first argument so that all
-     files are traced.
-
-     See the thread starting at
-     <http://lists.gnu.org/archive/html/bug-bison/2008-07/msg00000.html>
-     for details.  */
  int filter_fd[2];
  pid_t pid;
  {
-    char const *argv[10];
+    char const *argv[11];
    int i = 0;
    argv[i++] = m4;

@@ -730,15 +720,29 @@ output_skeleton (void)

    argv[i++] = "-I";
    argv[i++] = datadir;
-    if (trace_flag & trace_m4)
+    /* Some future version of GNU M4 (most likely 1.6) may treat the
+       -dV in a position-dependent manner.  See the thread starting at
+       <http://lists.gnu.org/archive/html/bug-bison/2008-07/msg00000.html>
+       for details.  */
+    if (trace_flag & trace_m4_early)
      argv[i++] = "-dV";
    argv[i++] = m4sugar;
    argv[i++] = "-";
    argv[i++] = m4bison;
+    if (trace_flag & trace_m4)
+      argv[i++] = traceon;
    argv[i++] = skel;
    argv[i++] = NULL;
    aver (i <= ARRAY_CARDINALITY (argv));

+    if (trace_flag & trace_tools)
+      {
+        fputs ("running:", stderr);
+        for (int j = 0; argv[j]; ++j)
+          fprintf (stderr, " %s", argv[j]);
+        fputc ('\n', stderr);
+      }
+
    /* The ugly cast is because gnulib gets the const-ness wrong.  */
    pid = create_pipe_bidi ("m4", m4, (char **)(void*)argv, false, true,
                            true, filter_fd);
@@ -747,6 +751,7 @@ output_skeleton (void)
  free (skeldir);
  free (m4sugar);
  free (m4bison);
+  free (traceon);
  free (skel);

  if (trace_flag & trace_muscles)
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.5.90.  */
+/* A Bison parser, made by GNU Bison 3.6.  */

 /* Bison implementation for Yacc-like parsers in C

@@ -49,7 +49,7 @@
 #define YYBISON 1

 /* Bison version.  */
-#define YYBISON_VERSION "3.5.90"
+#define YYBISON_VERSION "3.6"

 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -408,6 +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;

@@ -1304,8 +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");
    }
 }
@@ -1631,6 +1632,8 @@ yypcontext_expected_tokens (const yypcontext_t *yyctx,
              yyarg[yycount++] = yysym;
          }
    }
+  if (yyarg && yycount == 0 && 0 < yyargn)
+    yyarg[0] = YYSYMBOL_YYEMPTY;
  return yycount;
 }

@@ -2702,7 +2705,7 @@ 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];
@@ -2738,10 +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 3.5.90.  */
+/* A Bison parser, made by GNU Bison 3.6.  */

 /* Bison interface for Yacc-like parsers in C

@@ -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
@@ -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
      }
@@ -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
@@ -1352,8 +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.";

@@ -1424,6 +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
@@ -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
 [}
 ]])
@@ -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 +1,72 @@
+# 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_gsub([[abcd]],
+  [a], [b])
+b4_gsub([[abcd]],
+  [a], [b],
+  [b], [c],
+  [c], [d])
+
+_b4_comment([["/* () */"]])
+_b4_comment([["/* (  */"]])
+_b4_comment([["/*  ) */"]])
+_b4_comment([["/* [] */"]])
+
+b4_comment([["/* () */"]])
+b4_comment([["/* (  */"]])
+b4_comment([["/*  ) */"]])
+b4_comment([["/* [] */"]])
+
+b4_output_end([output.txt])
+]])
+
+AT_BISON_CHECK([-S ./input.m4 input.y])
+
+AT_CHECK([cat output.txt], [],
+[[
+[bbcd]
+[dddd]
+
+"/\* () *\/"
+"/\* (  *\/"
+"/\*  ) *\/"
+"/\* [] *\/"
+
+/* "/\* () *\/"  */
+/* "/\* (  *\/"  */
+/* "/\*  ) *\/"  */
+/* "/\* [] *\/"  */
+
+]])
+
+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 @@
 .5.90
 .6.3