version 3.5

* NEWS: Record release date.
news: prepare for 3.5
2026-08-08 10:15:14 +00:00 · 2019-12-11 07:41:51 +01:00 · 2019-12-10 07:06:04 +01:00 · 2019-12-08 16:34:53 +01:00 · 2019-12-08 16:07:50 +01:00 · 2019-12-08 16:03:36 +01:00
32 changed files with 833 additions and 634 deletions
@@ -1 +1 @@
-3.4.90
+3.4.92
@@ -1,8 +1,84 @@
 GNU Bison NEWS

-* Noteworthy changes in release 3.4.91 (2019-11-20) [beta]
+* Noteworthy changes in release 3.5 (2019-12-11) [stable]

-** New Features
+** Backward incompatible changes
+
+  Lone carriage-return characters (aka \r or ^M) in the grammar files are no
+  longer treated as end-of-lines.  This changes the diagnostics, and in
+  particular their locations.
+
+  In C++, line numbers and columns are now represented as 'int' not
+  'unsigned', so that integer overflow on positions is easily checkable via
+  'gcc -fsanitize=undefined' and the like.  This affects the API for
+  positions.  The default position and location classes now expose
+  'counter_type' (int), used to define line and column numbers.
+
+** Deprecated features
+
+  The YYPRINT macro, which works only with yacc.c and only for tokens, was
+  obsoleted long ago by %printer, introduced in Bison 1.50 (November 2002).
+  It is deprecated and its support will be removed eventually.
+
+** New features
+
+*** Lookahead correction in C++
+
+  Contributed by Adrian Vogelsgesang.
+
+  The C++ deterministic skeleton (lalr1.cc) now supports LAC, via the
+  %define variable parse.lac.
+
+*** Variable api.token.raw: Optimized token numbers (all skeletons)
+
+  In the generated parsers, tokens have two numbers: the "external" token
+  number as returned by yylex (which starts at 257), and the "internal"
+  symbol number (which starts at 3).  Each time yylex is called, a table
+  lookup maps the external token number to the internal symbol number.
+
+  When the %define variable api.token.raw is set, tokens are assigned their
+  internal number, which saves one table lookup per token, and also saves
+  the generation of the mapping table.
+
+  The gain is typically moderate, but in extreme cases (very simple user
+  actions), a 10% improvement can be observed.
+
+*** Generated parsers use better types for states
+
+  Stacks now use the best integral type for state numbers, instead of always
+  using 15 bits.  As a result "small" parsers now have a smaller memory
+  footprint (they use 8 bits), and there is support for large automata (16
+  bits), and extra large (using int, i.e., typically 31 bits).
+
+*** Generated parsers prefer signed integer types
+
+  Bison skeletons now prefer signed to unsigned integer types when either
+  will do, as the signed types are less error-prone and allow for better
+  checking with 'gcc -fsanitize=undefined'.  Also, the types chosen are now
+  portable to unusual machines where char, short and int are all the same
+  width.  On non-GNU platforms this may entail including <limits.h> and (if
+  available) <stdint.h> to define integer types and constants.
+
+*** A skeleton for the D programming language
+
+  For the last few releases, Bison has shipped a stealth experimental
+  skeleton: lalr1.d.  It was first contributed by Oliver Mangold, based on
+  Paolo Bonzini's lalr1.java, and was cleaned and improved thanks to
+  H. S. Teoh.
+
+  However, because nobody has committed to improving, testing, and
+  documenting this skeleton, it is not clear that it will be supported in
+  the future.
+
+  The lalr1.d skeleton *is functional*, and works well, as demonstrated in
+  examples/d/calc.d.  Please try it, enjoy it, and... commit to support it.
+
+*** Debug traces in Java
+
+  The Java backend no longer emits code and data for parser tracing if the
+  %define variable parse.trace is not defined.
+
+** Diagnostics

 *** New diagnostic: -Wdangling-alias

@@ -53,7 +129,7 @@ GNU Bison NEWS
    %%
    expr:

-  gives, with -Wyacc
+  gives with -Wyacc

    input.y:2.15-20: warning: POSIX yacc reserves %type to nonterminals [-Wyacc]
        2 | %type  <ival> TOKEN1 TOKEN2 't'
@@ -65,50 +141,9 @@ GNU Bison NEWS
        2 | %type  <ival> TOKEN1 TOKEN2 't'
          |                      ^~~~~~

-* Noteworthy changes in release 3.4.90 (2019-10-29) [beta]
-
-** Backward incompatible changes
-
-  Lone carriage-return characters (aka \r or ^M) in the grammar files are no
-  longer treated as end-of-lines.  This changes the diagnostics, and in
-  particular their locations.
-
-  In C++, line numbers and columns are now represented as 'int' not
-  'unsigned', so that integer overflow on positions is easily checkable via
-  'gcc -fsanitize=undefined' and the like.  This affects the API for
-  positions.  The default position and location classes now expose
-  'counter_type' (int), used to define line and column numbers.
-
-** Bug fixes
-
-  In Java, %define api.prefix was ignored.  It now behaves as expected.
-
-** New features
-
-*** Lookahead correction in C++
-
-  Contributed by Adrian Vogelsgesang.
-
-  The C++ deterministic skeleton (lalr1.cc) now supports LAC, via the
-  %define variable parse.lac.
-
-*** Variable api.token.raw: Optimized token numbers (all skeletons)
-
-  In the generated parsers, tokens have two numbers: the "external" token
-  number as returned by yylex (which starts at 257), and the "internal"
-  symbol number (which starts at 3).  Each time yylex is called, a table
-  lookup maps the external token number to the internal symbol number.
-
-  When the %define variable api.token.raw is set, tokens are assigned their
-  internal number, which saves one table lookup per token, and also saves
-  the generation of the mapping table.
-
-  The gain is typically moderate, but in extreme cases (very simple user
-  actions), a 10% improvement can be observed.
-
 *** Diagnostics with insertion

-  The diagnostics now display suggestion below the underlined source.
+  The diagnostics now display the suggestion below the underlined source.
  Replacement for undeclared symbols are now also suggested.

    $ cat /tmp/foo.y
@@ -149,26 +184,28 @@ GNU Bison NEWS
        1 | %token FOO                     …
          |        ^~~

-*** Debug traces in Java
+** Changes

-  The Java backend no longer emits code and data for parser tracing if the
-  %define variable parse.trace is not defined.
+*** Debugging glr.c and glr.cc

-*** Generated parsers prefer signed integer types
+  The glr.c skeleton always had asserts to check its own behavior (not the
+  user's).  These assertions are now under the control of the parse.assert
+  %define variable (disabled by default).

-  Bison skeletons now prefer signed to unsigned integer types when either
-  will do, as the signed types are less error-prone and allow for better
-  checking with 'gcc -fsanitize=undefined'.  Also, the types chosen are now
-  portable to unusual machines where char, short and int are all the same
-  width.  On non-GNU platforms this may entail including <limits.h> and (if
-  available) <stdint.h> to define integer types and constants.
+*** Clean up

-*** Generated parsers use better types for states
+  Several new compiler warnings in the generated output have been avoided.
+  Some unused features are no longer emitted.  Cleaner generated code in
+  general.

-  Stacks now use the best integral type for state numbers, instead of always
-  using 15 bits.  As a result "small" parsers now have a smaller memory
-  footprint (they use 8 bits), and there is support for large automata (16
-  bits), and extra large (using int, i.e., typically 31 bits).
+** Bug Fixes
+
+  Portability issues in the test suite.
+
+  In theory, parsers using %nonassoc could crash when reporting verbose
+  error messages. This unlikely bug has been fixed.
+
+  In Java, %define api.prefix was ignored.  It now behaves as expected.

 * Noteworthy changes in release 3.4.2 (2019-09-12) [stable]

@@ -3820,7 +3857,9 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 LocalWords:  Heimbigner AST src ast Makefile srcdir MinGW xxlex XXSTYPE
 LocalWords:  XXLTYPE strictfp IDEs ffixit fdiagnostics parseable fixits
 LocalWords:  Wdeprecated yytext Variadic variadic yyrhs yyphrs RCS README
- LocalWords:  noexcept constexpr ispell american deprecations backend
+ LocalWords:  noexcept constexpr ispell american deprecations backend Teoh
+ LocalWords:  YYPRINT Mangold Bonzini's Wdangling exVal baz checkable gcc
+ LocalWords:  fsanitize Vogelsgesang lis redeclared stdint automata

 Local Variables:
 ispell-dictionary: "american"
@@ -9,8 +9,7 @@ Here are basic installation instructions for a repository checkout:

 then proceed with the usual `configure && make` steps.

-The file README-hacking.md contains all the needed information about
-building, modifying and checking Bison.
+The file README-hacking.md is about building, modifying and checking Bison.

 ## Build from tarball
 See the file INSTALL for generic compilation and installation instructions.
@@ -185,29 +185,32 @@ These files don't change very often in Autoconf, so it should be relatively
 straight-forward to examine the differences in order to decide whether to
 update.

-# Test suite
+# Test Suite

 ## make check
-Use liberally.
+Consume without moderation.  It is composed of two kinds of tests: the
+examples, and the main test suite.

-## Updating the expectations
-Sometimes some changes have a large impact on the test suite (e.g., when we
-added the `[-Wother]` part to all the warnings).  Part of the update can be
-done with a crude tool: `build-aux/update-test`.
+### The Examples
+In examples/, there is a number of ready-to-use examples (see
+examples/README.md).  These examples have small test suites run by `make
+check`.  The test results are in local `*.log` files (e.g.,
+`$build/examples/c/calc/calc.log`).

-Once you ran the test suite, and therefore have many testsuite.log files,
-run, from the source tree:
+### The Main Test Suite
+The main test suite, in tests/, is written on top of GNU Autotest, which is
+part of Autoconf.  Run `info autoconf 'Using Autotest'` to read the
+documentation, not only about how to write tests, but also where are the
+logs, how to read them etc.

-    $ ./build-aux/update-test _build/tests/testsuite.dir/*/testsuite.log
+The main test suite generates a log for each test (e.g.,
+`$build/tests/testsuite.dir/004/testsuite.log` for test #4), and a main log
+file in `$build/tests/testsuite.log`.  The latter is meant for end users: it
+contains lots of details that should help diagnosing issues, including build
+issues.  The per-test logs are more convenient when working locally.

-where `_build` would be your build tree.  This will hopefully update most
-tests.  Re-run the test suite.  It might be interesting to run `update-test`
-again, since some early failures may stop latter tests from being run.  Yet
-at some point, you'll have to fix remaining issues by hand...
-
-## TESTSUITEFLAGS
-To run just the test suite (not the tests related to the examples), run `make
-check-local`.
+#### TESTSUITEFLAGS
+To run just the main test suite, run `make check-local`.

 The default is for make check-local to run all tests sequentially.  This can
 be very time consuming when checking repeatedly or on slower setups.  This
@@ -230,6 +233,10 @@ with AT_KEYWORDS([[category]]). Categories include:
 - java, for java parsers
 - report, for automaton dumps

+To get a list of all the tests (and their keywords for -k), run
+
+    $ ./tests/testsuite -l
+
 To run a specific set of tests, use -k (for "keyword"). For example:

    $ make check-local TESTSUITEFLAGS='-k c++'
@@ -242,18 +249,21 @@ To rerun the tests that failed:

    $ make recheck -j5

-## Typical errors
-If the test suite shows failures such as the following one
+#### Updating the Expectations
+Sometimes some changes have a large impact on the test suite (e.g., when we
+added the `[-Wother]` part to all the warnings).  Part of the update can be
+done with a crude tool: `build-aux/update-test`.

-    .../bison/lib/getopt.h:196:8: error: redefinition of 'struct option'
-    /usr/include/getopt.h:54:8: error: previous definition of 'struct option'
+Once you ran the test suite, and therefore have many `testsuite.log` files,
+run, from the source tree:

-it probably means that some file was compiled without
-`AT_DATA_SOURCE_PROLOGUE`.  This error is due to the fact that our -I
-options pick up gnulib's replacement headers, such as getopt.h, and this
-will go wrong if config.h was not included first.
+    $ ./build-aux/update-test $build/tests/testsuite.dir/*/testsuite.log
+
+where `$build` would be your build tree.  This will hopefully update most
+tests.  Re-run the test suite.  It might be interesting to run `update-test`
+again, since some early failures may stop latter tests from being run.  Yet
+at some point, you'll have to fix remaining issues by hand...

-See tests/local.at for details.

 ## make maintainer-check-valgrind
 This target uses valgrind both to check bison, and the generated parsers.
@@ -363,7 +373,7 @@ of every year by running `make update-copyright`.  However, before a
 release, it's good to verify that it's actually been run.  Besides the
 copyright statement for each Bison file, check the copyright statements that
 the skeletons insert into generated parsers, and check all occurrences of
-PACKAGE_COPYRIGHT_YEAR in configure.ac.
+`PACKAGE_COPYRIGHT_YEAR` in configure.ac.

 ## Update NEWS, commit and tag.
 See do-release-commit-and-tag in README-release.  For a while, we used beta
@@ -205,8 +205,9 @@ Wwp                       [email protected]
 xolodho                   [email protected]
 Yuichiro Kaneko           [email protected]
 Zack Weinberg             [email protected]
-長田偉伸                   [email protected]
 江 祖铭                    [email protected]
+長田偉伸                   [email protected]
+马俊                       [email protected]

 Many people are not named here because we lost track of them.  We
 thank them!  Please, help us keeping this list up to date.
@@ -1,4 +1,4 @@
-* Bison 3.5
+* Bison 3.6
 ** doc
 I feel its ugly to use the GNU style to declare functions in the doc.  It
 generates tons of white space in the page, and may contribute to bad page
@@ -50,12 +50,72 @@ syntax error, unexpected $end, expecting ↦ or 🎅🐃 or '\n'
 While at it, we should stop using "$end" by default, in favor of "end of
 file", or "end of input", whatever.  See how lalr1.java does that.

+** consistency
+token vs terminal, variable vs non terminal.
+
+** Stop indentation in diagnostics
+Before Bison 2.7, we printed "flatly" the dependencies in long diagnostics:
+
+    input.y:2.7-12: %type redeclaration for exp
+    input.y:1.7-12: previous declaration
+
+In Bison 2.7, we indented them
+
+    input.y:2.7-12: error: %type redeclaration for exp
+    input.y:1.7-12:     previous declaration
+
+Later we quoted the source in the diagnostics, and today we have:
+
+    /tmp/foo.y:1.12-14: warning: symbol FOO redeclared [-Wother]
+        1 | %token FOO FOO
+          |            ^~~
+    /tmp/foo.y:1.8-10:      previous declaration
+        1 | %token FOO FOO
+          |        ^~~
+
+The indentation is no longer helping.  We should probably get rid of it, or
+maybe keep it only when -fno-caret. GCC displays this as a "note":
+
+    $ g++-mp-9 -Wall /tmp/foo.c -c
+    /tmp/foo.c:1:10: error: redefinition of 'int foo'
+        1 | int foo, foo;
+          |          ^~~
+    /tmp/foo.c:1:5: note: 'int foo' previously declared here
+        1 | int foo, foo;
+          |     ^~~
+
+Likewise for Clang, contrary to what I believed (because "note:" is written
+in black, so it doesn't show in my terminal :-)
+
+    $ clang++-mp-8.0 -Wall /tmp/foo.c -c
+    clang: warning: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated [-Wdeprecated]
+    /tmp/foo.c:1:10: error: redefinition of 'foo'
+    int foo, foo;
+             ^
+    /tmp/foo.c:1:5: note: previous definition is here
+    int foo, foo;
+        ^
+    1 error generated.
+
+See also the item "Complaint submessage indentation" below.
+
 ** api.token.raw
 Maybe we should exhibit the YYUNDEFTOK token.  It could also be assigned a
 semantic value so that yyerror could be used to report invalid lexemes.
 See also the item "$undefined" below.

-* Bison 3.6
+** C++
+Move to int everywhere instead of unsigned?  stack_size, etc.  The parser
+itself uses int (for yylen for instance), yet stack is based on size_t.
+
+Maybe locations should also move to ints.
+
+Paul Eggert already covered most of this.  But before publishing these
+changes, we need to ask our C++ users if they agree with that change, or if
+we need some migration path.  Could be a %define variable, or simply
+%require "3.5".
+
+* Bison 3.7
 ** 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.,
@@ -134,51 +194,8 @@ $ ./tests/testsuite -l | grep errors | sed q
  38: input.at:1730      errors

 * Short term
-** Stop indentation in diagnostics
-Before Bison 2.7, we printed "flatly" the dependencies in long diagnostics:
-
-    input.y:2.7-12: %type redeclaration for exp
-    input.y:1.7-12: previous declaration
-
-In Bison 2.7, we indented them
-
-    input.y:2.7-12: error: %type redeclaration for exp
-    input.y:1.7-12:     previous declaration
-
-Later we quoted the source in the diagnostics, and today we have:
-
-    /tmp/foo.y:1.12-14: warning: symbol FOO redeclared [-Wother]
-        1 | %token FOO FOO
-          |            ^~~
-    /tmp/foo.y:1.8-10:      previous declaration
-        1 | %token FOO FOO
-          |        ^~~
-
-The indentation is no longer helping.  We should probably get rid of it, or
-maybe keep it only when -fno-caret. GCC displays this as a "note":
-
-    $ g++-mp-9 -Wall /tmp/foo.c -c
-    /tmp/foo.c:1:10: error: redefinition of 'int foo'
-        1 | int foo, foo;
-          |          ^~~
-    /tmp/foo.c:1:5: note: 'int foo' previously declared here
-        1 | int foo, foo;
-          |     ^~~
-
-Likewise for Clang, contrary to what I believed (because "note:" is written
-in black, so it doesn't show in my terminal :-)
-
-    $ clang++-mp-8.0 -Wall /tmp/foo.c -c
-    clang: warning: treating 'c' input as 'c++' when in C++ mode, this behavior is deprecated [-Wdeprecated]
-    /tmp/foo.c:1:10: error: redefinition of 'foo'
-    int foo, foo;
-             ^
-    /tmp/foo.c:1:5: note: previous definition is here
-    int foo, foo;
-        ^
-    1 error generated.
-
-See also the item "Complaint submessage indentation" below.
+** Get rid of YYPRINT and b4_toknum
+Besides yytoknum is wrong when api.token.raw is defined.

 ** Better design for diagnostics
 The current implementation of diagnostics is adhoc, it grew organically.  It
@@ -214,20 +231,6 @@ page:

 https://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Message-Formatting-Options.html

-** consistency
-token vs terminal, variable vs non terminal.
-
-** C++
-Move to int everywhere instead of unsigned?  stack_size, etc.  The parser
-itself uses int (for yylen for instance), yet stack is based on size_t.
-
-Maybe locations should also move to ints.
-
-Paul Eggert already covered most of this.  But before publishing these
-changes, we need to ask our C++ users if they agree with that change, or if
-we need some migration path.  Could be a %define variable, or simply
-%require "3.5".
-
 ** Graphviz display code thoughts
 The code for the --graph option is over two files: print_graph, and
 graphviz. This is because Bison used to also produce VCG graphs, but since
@@ -600,23 +603,6 @@ to bison. If you're interested, I'll work on a patch.
 * Better graphics
 Equip the parser with a means to create the (visual) parse tree.

-* Complaint submessage indentation.
-We already have an implementation that works fairly well for named
-reference messages, but it would be nice to use it consistently for all
-submessages from Bison.  For example, the "previous definition"
-submessage or the list of correct values for a %define variable might
-look better with indentation.
-
-However, the current implementation makes the assumption that the
-location printed on the first line is not usually much shorter than the
-locations printed on the submessage lines that follow.  That assumption
-may not hold true as often for some kinds of submessages especially if
-we ever support multiple grammar files.
-
-Here's a proposal for how a new implementation might look:
-
-  http://lists.gnu.org/archive/html/bison-patches/2009-09/msg00086.html
-

 Local Variables:
 mode: outline
@@ -151,8 +151,6 @@ if test "$enable_gcc_warnings" = yes; then

  # Warnings for the test suite, and maybe for bison if GCC is modern
  # enough.
-  gl_WARN_ADD([-Wmissing-declarations], [WARN_CFLAGS_TEST])
-  gl_WARN_ADD([-Wmissing-prototypes], [WARN_CFLAGS_TEST])
  test $lv_cv_gcc_pragma_push_works = yes &&
    AS_VAR_APPEND([WARN_CFLAGS], [" $WARN_CFLAGS_TEST"])

@@ -179,6 +177,14 @@ if test "$enable_gcc_warnings" = yes; then
              [[if (sizeof (long) < sizeof (int)) return 1;]])])
  gl_WARN_ADD([-Wzero-as-null-pointer-constant], [WARN_CXXFLAGS],
              [AC_LANG_PROGRAM([], [nullptr])])
+  # Before GCC6, the pragmas don't work well enough to neutralize
+  # this warning.
+  gl_WARN_ADD([-Wuseless-cast], [WARN_CXXFLAGS],
+              [AC_LANG_PROGRAM([], [
+              #if defined __GNUC__ && ! defined __ICC && ! defined __clang__ && __GNUC__ < 6
+              syntax error
+              #endif
+              ])])
  gl_WARN_ADD([-Werror], [WERROR_CXXFLAGS])
  # Warnings for the test suite only.
  for i in $warn_tests;
@@ -192,7 +192,7 @@ m4_define([b4_error],
 #   @warn(1@)
 #   @warn(1@,2@)
 m4_define([b4_warn],
-[b4_error([[warn]], [], [], $@)])
+[b4_warn_at([], [], $@)])

 # b4_warn_at(START, END, FORMAT, [ARG1], [ARG2], ...)
 # ---------------------------------------------------
@@ -210,7 +210,7 @@ m4_define([b4_warn_at],
 #
 # See b4_warn example.
 m4_define([b4_complain],
-[b4_error([[complain]], [], [], $@)])
+[b4_complain_at([], [], $@)])

 # b4_complain_at(START, END, FORMAT, [ARG1], [ARG2], ...)
 # -------------------------------------------------------
@@ -226,8 +226,7 @@ m4_define([b4_complain_at],
 #
 # See b4_warn example.
 m4_define([b4_fatal],
-[b4_error([[fatal]], [], [], $@)dnl
-m4_exit(1)])
+[b4_fatal_at([], [], $@)])

 # b4_fatal_at(START, END, FORMAT, [ARG1], [ARG2], ...)
 # ----------------------------------------------------
@@ -976,8 +975,8 @@ m4_define([b4_percent_code_get],
 [m4_pushdef([b4_macro_name], [[b4_percent_code(]$1[)]])dnl
 m4_ifval([$1], [m4_define([b4_percent_code_bison_qualifiers(]$1[)])])dnl
 m4_ifdef(b4_macro_name,
-[b4_comment([m4_if([$#], [0], [[Unqualified %code]],
-                   [["%code ]$1["]])[ blocks.]])
+[b4_comment(m4_if([$#], [0], [[[Unqualified %code blocks.]]],
+                  [[["%code ]$1[" blocks.]]]))
 b4_user_code([m4_indir(b4_macro_name)])])dnl
 m4_popdef([b4_macro_name])])

@@ -367,9 +367,6 @@ m4_define([b4_symbol_type_define],
      /// \a empty when empty.
      symbol_number_type type_get () const YY_NOEXCEPT;

-      /// The token.
-      token_type token () const YY_NOEXCEPT;
-
      /// The symbol type.
      /// \a empty_symbol when empty.
      /// An int, not token_number_type, to be able to store empty_symbol.
@@ -498,22 +495,7 @@ m4_define([b4_public_types_define],
  {
    return type;
  }
-]b4_token_ctor_if([[
-  ]b4_inline([$1])b4_parser_class[::token_type
-  ]b4_parser_class[::by_type::token () const YY_NOEXCEPT
-  {
-    // YYTOKNUM[NUM] -- (External) token number corresponding to the
-    // (internal) symbol number NUM (which must be that of a token).  */
-    static
-    const ]b4_int_type_for([b4_toknum])[
-    yytoken_number_[] =
-    {
-  ]b4_toknum[
-    };
-    return token_type (yytoken_number_[type]);
-  }
-]])[]dnl
-])
+]])


 # b4_token_constructor_define
@@ -529,11 +511,10 @@ m4_define([b4_token_constructor_define], [])
 # sometimes in the cc file.
 m4_define([b4_yytranslate_define],
 [  b4_inline([$1])b4_parser_class[::token_number_type
-  ]b4_parser_class[::yytranslate_ (]b4_token_ctor_if([token_type],
-                                                          [int])[ t)
+  ]b4_parser_class[::yytranslate_ (int t)
  {
 ]b4_api_token_raw_if(
-[[    return static_cast<yy::parser::token_number_type> (t);]],
+[[    return static_cast<token_number_type> (t);]],
 [[    // YYTRANSLATE[TOKEN-NUM] -- Symbol number corresponding to
    // TOKEN-NUM as returned by yylex.
    static
@@ -543,14 +524,13 @@ m4_define([b4_yytranslate_define],
  ]b4_translate[
    };
    const int user_token_number_max_ = ]b4_user_token_number_max[;
-    const token_number_type undef_token_ = ]b4_undef_token_number[;

-    if (static_cast<int> (t) <= yyeof_)
+    if (t <= 0)
      return yyeof_;
-    else if (static_cast<int> (t) <= user_token_number_max_)
+    else if (t <= user_token_number_max_)
      return translate_table[t];
    else
-      return undef_token_;]])[
+      return yy_undef_token_;]])[
  }
 ]])

@@ -327,11 +327,11 @@ m4_define([b4_attribute_define],

 #if defined __GNUC__ && ! defined __ICC && 407 <= __GNUC__ * 100 + __GNUC_MINOR__
 /* Suppress an incorrect diagnostic about yylval being uninitialized.  */
-# define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN \
-    _Pragma ("GCC diagnostic push") \
-    _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"")\
+# define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN                            \
+    _Pragma ("GCC diagnostic push")                                     \
+    _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"")              \
    _Pragma ("GCC diagnostic ignored \"-Wmaybe-uninitialized\"")
-# define YY_IGNORE_MAYBE_UNINITIALIZED_END \
+# define YY_IGNORE_MAYBE_UNINITIALIZED_END      \
    _Pragma ("GCC diagnostic pop")
 #else
 # define YY_INITIAL_VALUE(Value) Value
@@ -343,6 +343,18 @@ m4_define([b4_attribute_define],
 #ifndef YY_INITIAL_VALUE
 # define YY_INITIAL_VALUE(Value) /* Nothing. */
 #endif
+
+#if defined __cplusplus && defined __GNUC__ && ! defined __ICC && 6 <= __GNUC__
+# define YY_IGNORE_USELESS_CAST_BEGIN                          \
+    _Pragma ("GCC diagnostic push")                            \
+    _Pragma ("GCC diagnostic ignored \"-Wuseless-cast\"")
+# define YY_IGNORE_USELESS_CAST_END            \
+    _Pragma ("GCC diagnostic pop")
+#endif
+#ifndef YY_IGNORE_USELESS_CAST_BEGIN
+# define YY_IGNORE_USELESS_CAST_BEGIN
+# define YY_IGNORE_USELESS_CAST_END
+#endif
 ]])


@@ -311,15 +311,20 @@ static YYLTYPE yyloc_default][]b4_yyloc_default;])[
 # define YYLONGJMP(Env, Val)                    \
 do {                                           \
   longjmp (Env, Val);                          \
-   YYASSERT (0);                                \
+   YY_ASSERT (0);                               \
 } while (yyfalse)
 #endif

 ]b4_attribute_define([noreturn])[

-#ifndef YYASSERT
-# define YYASSERT(Condition) ((void) ((Condition) || (abort (), 0)))
+]b4_parse_assert_if([[#ifdef NDEBUG
+# define YY_ASSERT(E) ((void) (0 && (E)))
+#else
+# include <assert.h> /* INFRINGES ON USER NAME SPACE */
+# define YY_ASSERT(E) assert (E)
 #endif
+]],
+[[#define YY_ASSERT(E) ((void) (0 && (E)))]])[

 /* YYFINAL -- State number of the termination state.  */
 #define YYFINAL  ]b4_final_state_number[
@@ -470,23 +475,36 @@ typedef enum { yyok, yyaccept, yyabort, yyerr } YYRESULTTAG;
 #  define YYFPRINTF fprintf
 # endif

-]b4_yy_location_print_define[
+# define YY_FPRINTF                             \
+  YY_IGNORE_USELESS_CAST_BEGIN YY_FPRINTF_

-# define YYDPRINTF(Args)                        \
+# define YY_FPRINTF_(Args)                      \
+  do {                                          \
+    YYFPRINTF Args;                             \
+    YY_IGNORE_USELESS_CAST_END                  \
+  } while (0)
+
+# define YY_DPRINTF                             \
+  YY_IGNORE_USELESS_CAST_BEGIN YY_DPRINTF_
+
+# define YY_DPRINTF_(Args)                      \
  do {                                          \
    if (yydebug)                                \
      YYFPRINTF Args;                           \
+    YY_IGNORE_USELESS_CAST_END                  \
  } while (0)

+]b4_yy_location_print_define[
+
 ]b4_yy_symbol_print_define[

 # define YY_SYMBOL_PRINT(Title, Type, Value, Location)                  \
  do {                                                                  \
    if (yydebug)                                                        \
      {                                                                 \
-        YYFPRINTF (stderr, "%s ", Title);                               \
+        YY_FPRINTF ((stderr, "%s ", Title));                            \
        yy_symbol_print (stderr, Type, Value]b4_locuser_args([Location])[);        \
-        YYFPRINTF (stderr, "\n");                                       \
+        YY_FPRINTF ((stderr, "\n"));                                    \
      }                                                                 \
  } while (0)

@@ -502,7 +520,7 @@ static void yypdumpstack (struct yyGLRStack* yystackp)

 #else /* !]b4_api_PREFIX[DEBUG */

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

 #endif /* !]b4_api_PREFIX[DEBUG */
@@ -743,10 +761,7 @@ yyMemoryExhausted (yyGLRStack* yystackp)
 static inline const char*
 yytokenName (yySymbol yytoken)
 {
-  if (yytoken == YYEMPTY)
-    return "";
-
-  return yytname[yytoken];
+  return yytoken == YYEMPTY ? "" : yytname[yytoken];
 }
 #endif

@@ -786,7 +801,7 @@ yygetToken (int *yycharp][]b4_pure_if([, yyGLRStack* yystackp])[]b4_user_formals
 ]b4_parse_param_use()dnl
 [  if (*yycharp == YYEMPTY)
    {
-      YYDPRINTF ((stderr, "Reading a token: "));]b4_glr_cc_if([[
+      YY_DPRINTF ((stderr, "Reading a token: "));]b4_glr_cc_if([[
 #if YY_EXCEPTIONS
      try
        {
@@ -796,7 +811,7 @@ yygetToken (int *yycharp][]b4_pure_if([, yyGLRStack* yystackp])[]b4_user_formals
        }
      catch (const ]b4_namespace_ref[::]b4_parser_class[::syntax_error& yyexc)
        {
-          YYDPRINTF ((stderr, "Caught exception: %s\n", yyexc.what()));]b4_locations_if([
+          YY_DPRINTF ((stderr, "Caught exception: %s\n", yyexc.what()));]b4_locations_if([
          yylloc = yyexc.location;])[
          yyerror (]b4_lyyerror_args[yyexc.what ());
          // Map errors caught in the scanner to the undefined token
@@ -810,7 +825,7 @@ yygetToken (int *yycharp][]b4_pure_if([, yyGLRStack* yystackp])[]b4_user_formals
  if (*yycharp <= YYEOF)
    {
      *yycharp = yytoken = YYEOF;
-      YYDPRINTF ((stderr, "Now at end of input.\n"));
+      YY_DPRINTF ((stderr, "Now at end of input.\n"));
    }
  else
    {
@@ -846,8 +861,7 @@ yyuserAction (yyRuleNum yyn, int yyrhslen, yyGLRStackItem* yyvsp,
              yyGLRStack* yystackp,
              YYSTYPE* yyvalp]b4_locuser_formals[)
 {
-  yybool yynormal YY_ATTRIBUTE_UNUSED
-    = YY_CAST (yybool, yystackp->yysplitPoint == YY_NULLPTR);
+  yybool yynormal YY_ATTRIBUTE_UNUSED = yystackp->yysplitPoint == YY_NULLPTR;
  int yylow;
 ]b4_parse_param_use([yyvalp], [yylocp])dnl
 [  YYUSE (yyrhslen);
@@ -893,7 +907,7 @@ yyuserAction (yyRuleNum yyn, int yyrhslen, yyGLRStackItem* yyvsp,
  }
  catch (const syntax_error& yyexc)
    {
-      YYDPRINTF ((stderr, "Caught exception: %s\n", yyexc.what()));]b4_locations_if([
+      YY_DPRINTF ((stderr, "Caught exception: %s\n", yyexc.what()));]b4_locations_if([
      *yylocp = yyexc.location;])[
      yyerror (]b4_yyerror_args[yyexc.what ());
      YYERROR;
@@ -947,9 +961,9 @@ yydestroyGLRState (char const *yymsg, yyGLRState *yys]b4_user_formals[)
      if (yydebug)
        {
          if (yys->yysemantics.yyfirstVal)
-            YYFPRINTF (stderr, "%s unresolved", yymsg);
+            YY_FPRINTF ((stderr, "%s unresolved", yymsg));
          else
-            YYFPRINTF (stderr, "%s incomplete", yymsg);
+            YY_FPRINTF ((stderr, "%s incomplete", yymsg));
          YY_SYMBOL_PRINT ("", yystos[yys->yylrState], YY_NULLPTR, &yys->yyloc);
        }
 #endif
@@ -982,7 +996,7 @@ yylhsNonterm (yyRuleNum yyrule)
 static inline yybool
 yyisDefaultedState (yyStateNum yystate)
 {
-  return YY_CAST (yybool, yypact_value_is_default (yypact[yystate]));
+  return yypact_value_is_default (yypact[yystate]);
 }

 /** The default reduction for YYSTATE, assuming it has one.  */
@@ -1042,13 +1056,13 @@ yyLRgotoState (yyStateNum yystate, yySymbol yysym)
 static inline yybool
 yyisShiftAction (int yyaction)
 {
-  return YY_CAST (yybool, 0 < yyaction);
+  return 0 < yyaction;
 }

 static inline yybool
 yyisErrorAction (int yyaction)
 {
-  return YY_CAST (yybool, yyaction == 0);
+  return yyaction == 0;
 }

                                /* GLRStates */
@@ -1078,7 +1092,7 @@ yyaddDeferredAction (yyGLRStack* yystackp, ptrdiff_t yyk, yyGLRState* yystate,
 {
  yySemanticOption* yynewOption =
    &yynewGLRStackItem (yystackp, yyfalse)->yyoption;
-  YYASSERT (!yynewOption->yyisState);
+  YY_ASSERT (!yynewOption->yyisState);
  yynewOption->yystate = yyrhs;
  yynewOption->yyrule = yyrule;
  if (yystackp->yytops.yylookaheadNeeds[yyk])
@@ -1259,7 +1273,7 @@ yyundeleteLastStack (yyGLRStack* yystackp)
    return;
  yystackp->yytops.yystates[0] = yystackp->yylastDeleted;
  yystackp->yytops.yysize = 1;
-  YYDPRINTF ((stderr, "Restoring last deleted stack as stack #0.\n"));
+  YY_DPRINTF ((stderr, "Restoring last deleted stack as stack #0.\n"));
  yystackp->yylastDeleted = YY_NULLPTR;
 }

@@ -1273,9 +1287,7 @@ yyremoveDeletes (yyGLRStack* yystackp)
      if (yystackp->yytops.yystates[yyi] == YY_NULLPTR)
        {
          if (yyi == yyj)
-            {
-              YYDPRINTF ((stderr, "Removing dead stacks.\n"));
-            }
+            YY_DPRINTF ((stderr, "Removing dead stacks.\n"));
          yystackp->yytops.yysize -= 1;
        }
      else
@@ -1289,10 +1301,8 @@ yyremoveDeletes (yyGLRStack* yystackp)
          yystackp->yytops.yylookaheadNeeds[yyj] =
            yystackp->yytops.yylookaheadNeeds[yyi];
          if (yyj != yyi)
-            {
-              YYDPRINTF ((stderr, "Rename stack %ld -> %ld.\n",
-                          YY_CAST (long, yyi), YY_CAST (long, yyj)));
-            }
+            YY_DPRINTF ((stderr, "Rename stack %ld -> %ld.\n",
+                        YY_CAST (long, yyi), YY_CAST (long, yyj)));
          yyj += 1;
        }
      yyi += 1;
@@ -1328,7 +1338,7 @@ yyglrShiftDefer (yyGLRStack* yystackp, ptrdiff_t yyk, yyStateNum yylrState,
                 ptrdiff_t yyposn, yyGLRState* yyrhs, yyRuleNum yyrule)
 {
  yyGLRState* yynewState = &yynewGLRStackItem (yystackp, yytrue)->yystate;
-  YYASSERT (yynewState->yyisState);
+  YY_ASSERT (yynewState->yyisState);

  yynewState->yylrState = yylrState;
  yynewState->yyposn = yyposn;
@@ -1361,22 +1371,22 @@ yy_reduce_print (yybool yynormal, yyGLRStackItem* yyvsp, ptrdiff_t yyk,
  int yynrhs = yyrhsLength (yyrule);]b4_locations_if([
  int yylow = 1;])[
  int yyi;
-  YYFPRINTF (stderr, "Reducing stack %ld by rule %d (line %d):\n",
-             YY_CAST (long, yyk), yyrule - 1, yyrline[yyrule]);
+  YY_FPRINTF ((stderr, "Reducing stack %ld by rule %d (line %d):\n",
+               YY_CAST (long, yyk), yyrule - 1, yyrline[yyrule]));
  if (! yynormal)
    yyfillin (yyvsp, 1, -yynrhs);
  /* The symbols being reduced.  */
  for (yyi = 0; yyi < yynrhs; yyi++)
    {
-      YYFPRINTF (stderr, "   $%d = ", yyi + 1);
+      YY_FPRINTF ((stderr, "   $%d = ", yyi + 1));
      yy_symbol_print (stderr,
                       yystos[yyvsp[yyi - yynrhs + 1].yystate.yylrState],
                       &yyvsp[yyi - yynrhs + 1].yystate.yysemantics.yysval]b4_locations_if([,
                       &]b4_rhs_location(yynrhs, yyi + 1))[]dnl
                       b4_user_args[);
      if (!yyvsp[yyi - yynrhs + 1].yystate.yyresolved)
-        YYFPRINTF (stderr, " (unresolved)");
-      YYFPRINTF (stderr, "\n");
+        YY_FPRINTF ((stderr, " (unresolved)"));
+      YY_FPRINTF ((stderr, "\n"));
    }
 }
 #endif
@@ -1398,7 +1408,7 @@ yydoAction (yyGLRStack* yystackp, ptrdiff_t yyk, yyRuleNum yyrule,
      /* Standard special case: single stack.  */
      yyGLRStackItem* yyrhs
        = YY_REINTERPRET_CAST (yyGLRStackItem*, yystackp->yytops.yystates[yyk]);
-      YYASSERT (yyk == 0);
+      YY_ASSERT (yyk == 0);
      yystackp->yynextFree -= yynrhs;
      yystackp->yyspaceLeft += yynrhs;
      yystackp->yytops.yystates[0] = & yystackp->yynextFree[-1].yystate;
@@ -1418,7 +1428,7 @@ yydoAction (yyGLRStack* yystackp, ptrdiff_t yyk, yyRuleNum yyrule,
      for (yyi = 0; yyi < yynrhs; yyi += 1)
        {
          yys = yys->yypred;
-          YYASSERT (yys);
+          YY_ASSERT (yys);
        }
      yyupdateSplit (yystackp, yys);
      yystackp->yytops.yystates[yyk] = yys;
@@ -1452,11 +1462,9 @@ yyglrReduce (yyGLRStack* yystackp, ptrdiff_t yyk, yyRuleNum yyrule,

      YYRESULTTAG yyflag = yydoAction (yystackp, yyk, yyrule, &yysval]b4_locuser_args([&yyloc])[);
      if (yyflag == yyerr && yystackp->yysplitPoint != YY_NULLPTR)
-        {
-          YYDPRINTF ((stderr,
-                      "Parse on stack %ld rejected by rule %d (line %d).\n",
-                      YY_CAST (long, yyk), yyrule - 1, yyrline[yyrule - 1]));
-        }
+        YY_DPRINTF ((stderr,
+                     "Parse on stack %ld rejected by rule %d (line %d).\n",
+                     YY_CAST (long, yyk), yyrule - 1, yyrline[yyrule - 1]));
      if (yyflag != yyok)
        return yyflag;
      YY_SYMBOL_PRINT ("-> $$ =", yyr1[yyrule], &yysval, &yyloc);
@@ -1476,15 +1484,15 @@ yyglrReduce (yyGLRStack* yystackp, ptrdiff_t yyk, yyRuleNum yyrule,
           0 < yyn; yyn -= 1)
        {
          yys = yys->yypred;
-          YYASSERT (yys);
+          YY_ASSERT (yys);
        }
      yyupdateSplit (yystackp, yys);
      yynewLRState = yyLRgotoState (yys->yylrState, yylhsNonterm (yyrule));
-      YYDPRINTF ((stderr,
-                  "Reduced stack %ld by rule %d (line %d); action deferred.  "
-                  "Now in state %d.\n",
-                  YY_CAST (long, yyk), yyrule - 1, yyrline[yyrule - 1],
-                  yynewLRState));
+      YY_DPRINTF ((stderr,
+                   "Reduced stack %ld by rule %d (line %d); action deferred.  "
+                   "Now in state %d.\n",
+                   YY_CAST (long, yyk), yyrule - 1, yyrline[yyrule - 1],
+                   yynewLRState));
      for (yyi = 0; yyi < yystackp->yytops.yysize; yyi += 1)
        if (yyi != yyk && yystackp->yytops.yystates[yyi] != YY_NULLPTR)
          {
@@ -1496,8 +1504,8 @@ yyglrReduce (yyGLRStack* yystackp, ptrdiff_t yyk, yyRuleNum yyrule,
                  {
                    yyaddDeferredAction (yystackp, yyk, yyp, yys0, yyrule);
                    yymarkStackDeleted (yystackp, yyk);
-                    YYDPRINTF ((stderr, "Merging stack %ld into stack %ld.\n",
-                                YY_CAST (long, yyk), YY_CAST (long, yyi)));
+                    YY_DPRINTF ((stderr, "Merging stack %ld into stack %ld.\n",
+                                 YY_CAST (long, yyk), YY_CAST (long, yyi)));
                    return yyok;
                  }
                yyp = yyp->yypred;
@@ -1514,44 +1522,45 @@ yysplitStack (yyGLRStack* yystackp, ptrdiff_t yyk)
 {
  if (yystackp->yysplitPoint == YY_NULLPTR)
    {
-      YYASSERT (yyk == 0);
+      YY_ASSERT (yyk == 0);
      yystackp->yysplitPoint = yystackp->yytops.yystates[yyk];
    }
-  if (yystackp->yytops.yysize >= yystackp->yytops.yycapacity)
+  if (yystackp->yytops.yycapacity <= yystackp->yytops.yysize)
    {
-      yyGLRState** yynewStates = YY_NULLPTR;
-      yybool* yynewLookaheadNeeds;
-      ptrdiff_t state_size = sizeof yynewStates[0];
+      ptrdiff_t state_size = sizeof yystackp->yytops.yystates[0];
      ptrdiff_t half_max_capacity = YYSIZEMAX / 2 / state_size;
-
      if (half_max_capacity < yystackp->yytops.yycapacity)
        yyMemoryExhausted (yystackp);
      yystackp->yytops.yycapacity *= 2;

-      yynewStates
-        = YY_CAST (yyGLRState**,
-                   YYREALLOC (yystackp->yytops.yystates,
-                              (YY_CAST (size_t, yystackp->yytops.yycapacity)
-                               * sizeof yynewStates[0])));
-      if (yynewStates == YY_NULLPTR)
-        yyMemoryExhausted (yystackp);
-      yystackp->yytops.yystates = yynewStates;
+      {
+        yyGLRState** yynewStates
+          = YY_CAST (yyGLRState**,
+                     YYREALLOC (yystackp->yytops.yystates,
+                                (YY_CAST (size_t, yystackp->yytops.yycapacity)
+                                 * sizeof yynewStates[0])));
+        if (yynewStates == YY_NULLPTR)
+          yyMemoryExhausted (yystackp);
+        yystackp->yytops.yystates = yynewStates;
+      }

-      yynewLookaheadNeeds
-        = YY_CAST (yybool*,
-                   YYREALLOC (yystackp->yytops.yylookaheadNeeds,
-                              (YY_CAST (size_t, yystackp->yytops.yycapacity)
-                               * sizeof yynewLookaheadNeeds[0])));
-      if (yynewLookaheadNeeds == YY_NULLPTR)
-        yyMemoryExhausted (yystackp);
-      yystackp->yytops.yylookaheadNeeds = yynewLookaheadNeeds;
+      {
+        yybool* yynewLookaheadNeeds
+          = YY_CAST (yybool*,
+                     YYREALLOC (yystackp->yytops.yylookaheadNeeds,
+                                (YY_CAST (size_t, yystackp->yytops.yycapacity)
+                                 * sizeof yynewLookaheadNeeds[0])));
+        if (yynewLookaheadNeeds == YY_NULLPTR)
+          yyMemoryExhausted (yystackp);
+        yystackp->yytops.yylookaheadNeeds = yynewLookaheadNeeds;
+      }
    }
  yystackp->yytops.yystates[yystackp->yytops.yysize]
    = yystackp->yytops.yystates[yyk];
  yystackp->yytops.yylookaheadNeeds[yystackp->yytops.yysize]
    = yystackp->yytops.yylookaheadNeeds[yyk];
  yystackp->yytops.yysize += 1;
-  return yystackp->yytops.yysize-1;
+  return yystackp->yytops.yysize - 1;
 }

 /** True iff YYY0 and YYY1 represent identical options at the top level.
@@ -1585,7 +1594,7 @@ yymergeOptionSets (yySemanticOption* yyy0, yySemanticOption* yyy1)
  int yyn;
  for (yys0 = yyy0->yystate, yys1 = yyy1->yystate,
       yyn = yyrhsLength (yyy0->yyrule);
-       yyn > 0;
+       0 < yyn;
       yys0 = yys0->yypred, yys1 = yys1->yypred, yyn -= 1)
    {
      if (yys0 == yys1)
@@ -1667,7 +1676,7 @@ yyresolveStates (yyGLRState* yys, int yyn,
 {
  if (0 < yyn)
    {
-      YYASSERT (yys->yypred);
+      YY_ASSERT (yys->yypred);
      YYCHK (yyresolveStates (yys->yypred, yyn-1, yystackp]b4_user_args[));
      if (! yys->yyresolved)
        YYCHK (yyresolveValue (yys, yystackp]b4_user_args[));
@@ -1738,26 +1747,26 @@ yyreportTree (yySemanticOption* yyx, int yyindent)
    yystates[0] = yys;

  if (yyx->yystate->yyposn < yys->yyposn + 1)
-    YYFPRINTF (stderr, "%*s%s -> <Rule %d, empty>\n",
-               yyindent, "", yytokenName (yylhsNonterm (yyx->yyrule)),
-               yyx->yyrule - 1);
+    YY_FPRINTF ((stderr, "%*s%s -> <Rule %d, empty>\n",
+                 yyindent, "", yytokenName (yylhsNonterm (yyx->yyrule)),
+                 yyx->yyrule - 1));
  else
-    YYFPRINTF (stderr, "%*s%s -> <Rule %d, tokens %ld .. %ld>\n",
-               yyindent, "", yytokenName (yylhsNonterm (yyx->yyrule)),
-               yyx->yyrule - 1, YY_CAST (long, yys->yyposn + 1),
-               YY_CAST (long, yyx->yystate->yyposn));
+    YY_FPRINTF ((stderr, "%*s%s -> <Rule %d, tokens %ld .. %ld>\n",
+                 yyindent, "", yytokenName (yylhsNonterm (yyx->yyrule)),
+                 yyx->yyrule - 1, YY_CAST (long, yys->yyposn + 1),
+                 YY_CAST (long, yyx->yystate->yyposn)));
  for (yyi = 1; yyi <= yynrhs; yyi += 1)
    {
      if (yystates[yyi]->yyresolved)
        {
          if (yystates[yyi-1]->yyposn+1 > yystates[yyi]->yyposn)
-            YYFPRINTF (stderr, "%*s%s <empty>\n", yyindent+2, "",
-                       yytokenName (yystos[yystates[yyi]->yylrState]));
+            YY_FPRINTF ((stderr, "%*s%s <empty>\n", yyindent+2, "",
+                         yytokenName (yystos[yystates[yyi]->yylrState])));
          else
-            YYFPRINTF (stderr, "%*s%s <tokens %ld .. %ld>\n", yyindent+2, "",
-                       yytokenName (yystos[yystates[yyi]->yylrState]),
-                       YY_CAST (long, yystates[yyi-1]->yyposn + 1),
-                       YY_CAST (long, yystates[yyi]->yyposn));
+            YY_FPRINTF ((stderr, "%*s%s <tokens %ld .. %ld>\n", yyindent+2, "",
+                         yytokenName (yystos[yystates[yyi]->yylrState]),
+                         YY_CAST (long, yystates[yyi-1]->yyposn + 1),
+                         YY_CAST (long, yystates[yyi]->yyposn)));
        }
      else
        yyreportTree (yystates[yyi]->yysemantics.yyfirstVal, yyindent+2);
@@ -1773,12 +1782,12 @@ yyreportAmbiguity (yySemanticOption* yyx0,
  YYUSE (yyx1);

 #if ]b4_api_PREFIX[DEBUG
-  YYFPRINTF (stderr, "Ambiguity detected.\n");
-  YYFPRINTF (stderr, "Option 1,\n");
+  YY_FPRINTF ((stderr, "Ambiguity detected.\n"));
+  YY_FPRINTF ((stderr, "Option 1,\n"));
  yyreportTree (yyx0, 2);
-  YYFPRINTF (stderr, "\nOption 2,\n");
+  YY_FPRINTF ((stderr, "\nOption 2,\n"));
  yyreportTree (yyx1, 2);
-  YYFPRINTF (stderr, "\n");
+  YY_FPRINTF ((stderr, "\n"));
 #endif

  yyerror (]b4_yyerror_args[YY_("syntax is ambiguous"));
@@ -1800,7 +1809,7 @@ yyresolveLocations (yyGLRState *yys1, int yyn1,
          yyGLRStackItem yyrhsloc[1 + YYMAXRHS];
          int yynrhs;
          yySemanticOption *yyoption = yys1->yysemantics.yyfirstVal;
-          YYASSERT (yyoption);
+          YY_ASSERT (yyoption);
          yynrhs = yyrhsLength (yyoption->yyrule);
          if (0 < yynrhs)
            {
@@ -1875,7 +1884,7 @@ yyresolveValue (yyGLRState* yys, yyGLRStack* yystackp]b4_user_formals[)
              yymerge = yyfalse;
              break;
            default:
-              /* This cannot happen so it is not worth a YYASSERT (yyfalse),
+              /* This cannot happen so it is not worth a YY_ASSERT (yyfalse),
                 but some compilers complain if the default case is
                 omitted.  */
              break;
@@ -1976,9 +1985,9 @@ yyprocessOneStack (yyGLRStack* yystackp, ptrdiff_t yyk,
  while (yystackp->yytops.yystates[yyk] != YY_NULLPTR)
    {
      yyStateNum yystate = yystackp->yytops.yystates[yyk]->yylrState;
-      YYDPRINTF ((stderr, "Stack %ld Entering state %d\n", yyk, yystate));
+      YY_DPRINTF ((stderr, "Stack %ld Entering state %d\n", yyk, yystate));

-      YYASSERT (yystate != YYFINAL);
+      YY_ASSERT (yystate != YYFINAL);

      if (yyisDefaultedState (yystate))
        {
@@ -1986,17 +1995,17 @@ yyprocessOneStack (yyGLRStack* yystackp, ptrdiff_t yyk,
          yyRuleNum yyrule = yydefaultAction (yystate);
          if (yyrule == 0)
            {
-              YYDPRINTF ((stderr, "Stack %ld dies.\n", YY_CAST (long, yyk)));
+              YY_DPRINTF ((stderr, "Stack %ld dies.\n", YY_CAST (long, yyk)));
              yymarkStackDeleted (yystackp, yyk);
              return yyok;
            }
          yyflag = yyglrReduce (yystackp, yyk, yyrule, yyimmediate[yyrule]]b4_user_args[);
          if (yyflag == yyerr)
            {
-              YYDPRINTF ((stderr,
-                          "Stack %ld dies "
-                          "(predicate failure or explicit user error).\n",
-                          YY_CAST (long, yyk)));
+              YY_DPRINTF ((stderr,
+                           "Stack %ld dies "
+                           "(predicate failure or explicit user error).\n",
+                           YY_CAST (long, yyk)));
              yymarkStackDeleted (yystackp, yyk);
              return yyok;
            }
@@ -2014,8 +2023,8 @@ yyprocessOneStack (yyGLRStack* yystackp, ptrdiff_t yyk,
            {
              YYRESULTTAG yyflag;
              ptrdiff_t yynewStack = yysplitStack (yystackp, yyk);
-              YYDPRINTF ((stderr, "Splitting off stack %ld from %ld.\n",
-                          YY_CAST (long, yynewStack), YY_CAST (long, yyk)));
+              YY_DPRINTF ((stderr, "Splitting off stack %ld from %ld.\n",
+                           YY_CAST (long, yynewStack), YY_CAST (long, yyk)));
              yyflag = yyglrReduce (yystackp, yynewStack,
                                    *yyconflicts,
                                    yyimmediate[*yyconflicts]]b4_user_args[);
@@ -2024,7 +2033,7 @@ yyprocessOneStack (yyGLRStack* yystackp, ptrdiff_t yyk,
                                          yyposn]b4_pure_args[));
              else if (yyflag == yyerr)
                {
-                  YYDPRINTF ((stderr, "Stack %ld dies.\n", YY_CAST (long, yynewStack)));
+                  YY_DPRINTF ((stderr, "Stack %ld dies.\n", YY_CAST (long, yynewStack)));
                  yymarkStackDeleted (yystackp, yynewStack);
                }
              else
@@ -2036,7 +2045,7 @@ yyprocessOneStack (yyGLRStack* yystackp, ptrdiff_t yyk,
            break;
          else if (yyisErrorAction (yyaction))
            {
-              YYDPRINTF ((stderr, "Stack %ld dies.\n", YY_CAST (long, yyk)));
+              YY_DPRINTF ((stderr, "Stack %ld dies.\n", YY_CAST (long, yyk)));
              yymarkStackDeleted (yystackp, yyk);
              break;
            }
@@ -2046,10 +2055,10 @@ yyprocessOneStack (yyGLRStack* yystackp, ptrdiff_t yyk,
                                                yyimmediate[-yyaction]]b4_user_args[);
              if (yyflag == yyerr)
                {
-                  YYDPRINTF ((stderr,
-                              "Stack %ld dies "
-                              "(predicate failure or explicit user error).\n",
-                              YY_CAST (long, yyk)));
+                  YY_DPRINTF ((stderr,
+                               "Stack %ld dies "
+                               "(predicate failure or explicit user error).\n",
+                               YY_CAST (long, yyk)));
                  yymarkStackDeleted (yystackp, yyk);
                  break;
                }
@@ -2071,18 +2080,18 @@ yyreportSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
 #else
  {
  yySymbol yytoken = yychar == YYEMPTY ? YYEMPTY : YYTRANSLATE (yychar);
-  ptrdiff_t yysize0 = yytnamerr (YY_NULLPTR, yytokenName (yytoken));
-  ptrdiff_t yysize = yysize0;
  yybool yysize_overflow = yyfalse;
  char* yymsg = YY_NULLPTR;
  enum { YYERROR_VERBOSE_ARGS_MAXIMUM = 5 };
  /* Internationalized format string. */
  const char *yyformat = YY_NULLPTR;
-  /* Arguments of yyformat. */
+  /* Arguments of yyformat: reported tokens (one for the "unexpected",
+     one per "expected"). */
  char const *yyarg[YYERROR_VERBOSE_ARGS_MAXIMUM];
-  /* Number of reported tokens (one for the "unexpected", one per
-     "expected").  */
+  /* Actual size of YYARG. */
  int yycount = 0;
+  /* Cumulated lengths of YYARG.  */
+  ptrdiff_t yysize = 0;

  /* There are many possibilities here to consider:
     - If this state is a consistent state with a default action, then
@@ -2110,6 +2119,8 @@ yyreportSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
  if (yytoken != YYEMPTY)
    {
      int yyn = yypact[yystackp->yytops.yystates[0]->yylrState];
+      ptrdiff_t yysize0 = yytnamerr (YY_NULLPTR, yytokenName (yytoken));
+      yysize = yysize0;
      yyarg[yycount++] = yytokenName (yytoken);
      if (!yypact_value_is_default (yyn))
        {
@@ -2160,7 +2171,9 @@ yyreportSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
    }

  {
-    ptrdiff_t yysz = YY_CAST (ptrdiff_t, strlen (yyformat));
+    /* Don't count the "%s"s in the final size, but reserve room for
+       the terminator.  */
+    ptrdiff_t yysz = YY_CAST (ptrdiff_t, strlen (yyformat)) - 2 * yycount + 1;
    if (YYSIZEMAX - yysize < yysz)
      yysize_overflow = yytrue;
    else
@@ -2183,8 +2196,8 @@ yyreportSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
            }
          else
            {
-              yyp++;
-              yyformat++;
+              ++yyp;
+              ++yyformat;
            }
        }
      yyerror (]b4_lyyerror_args[yymsg);
@@ -2321,7 +2334,7 @@ yyrecoverSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
  yyGLRStack* const yystackp = &yystack;
  ptrdiff_t yyposn;

-  YYDPRINTF ((stderr, "Starting parse\n"));
+  YY_DPRINTF ((stderr, "Starting parse\n"));

  yychar = YYEMPTY;
  yylval = yyval_default;]b4_locations_if([
@@ -2352,7 +2365,7 @@ b4_dollar_popdef])[]dnl
      while (yytrue)
        {
          yyStateNum yystate = yystack.yytops.yystates[0]->yylrState;
-          YYDPRINTF ((stderr, "Entering state %d\n", yystate));
+          YY_DPRINTF ((stderr, "Entering state %d\n", yystate));
          if (yystate == YYFINAL)
            goto yyacceptlab;
          if (yyisDefaultedState (yystate))
@@ -2402,7 +2415,7 @@ b4_dollar_popdef])[]dnl
          ptrdiff_t yys;

          for (yys = 0; yys < yystack.yytops.yysize; yys += 1)
-            yystackp->yytops.yylookaheadNeeds[yys] = YY_CAST (yybool, yychar != YYEMPTY);
+            yystackp->yytops.yylookaheadNeeds[yys] = yychar != YYEMPTY;

          /* yyprocessOneStack returns one of three things:

@@ -2432,7 +2445,7 @@ b4_dollar_popdef])[]dnl
              if (yystack.yytops.yysize == 0)
                yyFail (&yystack][]b4_lpure_args[, YY_("syntax error"));
              YYCHK1 (yyresolveStack (&yystack]b4_user_args[));
-              YYDPRINTF ((stderr, "Returning to deterministic operation.\n"));]b4_locations_if([[
+              YY_DPRINTF ((stderr, "Returning to deterministic operation.\n"));]b4_locations_if([[
              yystack.yyerror_range[1].yystate.yyloc = yylloc;]])[
              yyreportSyntaxError (&yystack]b4_user_args[);
              goto yyuser_error;
@@ -2453,19 +2466,19 @@ b4_dollar_popdef])[]dnl
              int yyaction = yygetLRActions (yystate, yytoken_to_shift,
                              &yyconflicts);
              /* Note that yyconflicts were handled by yyprocessOneStack.  */
-              YYDPRINTF ((stderr, "On stack %ld, ", YY_CAST (long, yys)));
+              YY_DPRINTF ((stderr, "On stack %ld, ", YY_CAST (long, yys)));
              YY_SYMBOL_PRINT ("shifting", yytoken_to_shift, &yylval, &yylloc);
              yyglrShift (&yystack, yys, yyaction, yyposn,
                          &yylval]b4_locations_if([, &yylloc])[);
-              YYDPRINTF ((stderr, "Stack %ld now in state #%d\n",
-                          YY_CAST (long, yys),
-                          yystack.yytops.yystates[yys]->yylrState));
+              YY_DPRINTF ((stderr, "Stack %ld now in state #%d\n",
+                           YY_CAST (long, yys),
+                           yystack.yytops.yystates[yys]->yylrState));
            }

          if (yystack.yytops.yysize == 1)
            {
              YYCHK1 (yyresolveStack (&yystack]b4_user_args[));
-              YYDPRINTF ((stderr, "Returning to deterministic operation.\n"));
+              YY_DPRINTF ((stderr, "Returning to deterministic operation.\n"));
              yycompressStack (&yystack);
              break;
            }
@@ -2481,7 +2494,7 @@ b4_dollar_popdef])[]dnl
  goto yyreturn;

 yybuglab:
-  YYASSERT (yyfalse);
+  YY_ASSERT (yyfalse);
  goto yyabortlab;

 yyabortlab:
@@ -2538,19 +2551,19 @@ yy_yypstack (yyGLRState* yys)
  if (yys->yypred)
    {
      yy_yypstack (yys->yypred);
-      YYFPRINTF (stderr, " -> ");
+      YY_FPRINTF ((stderr, " -> "));
    }
-  YYFPRINTF (stderr, "%d@@%ld", yys->yylrState, YY_CAST (long, yys->yyposn));
+  YY_FPRINTF ((stderr, "%d@@%ld", yys->yylrState, YY_CAST (long, yys->yyposn)));
 }

 static void
 yypstates (yyGLRState* yyst)
 {
  if (yyst == YY_NULLPTR)
-    YYFPRINTF (stderr, "<null>");
+    YY_FPRINTF ((stderr, "<null>"));
  else
    yy_yypstack (yyst);
-  YYFPRINTF (stderr, "\n");
+  YY_FPRINTF ((stderr, "\n"));
 }

 static void
@@ -2571,39 +2584,39 @@ yypdumpstack (yyGLRStack* yystackp)
  yyGLRStackItem* yyp;
  for (yyp = yystackp->yyitems; yyp < yystackp->yynextFree; yyp += 1)
    {
-      YYFPRINTF (stderr, "%3ld. ",
-                 YY_CAST (long, yyp - yystackp->yyitems));
+      YY_FPRINTF ((stderr, "%3ld. ",
+                   YY_CAST (long, yyp - yystackp->yyitems)));
      if (*YY_REINTERPRET_CAST (yybool *, yyp))
        {
-          YYASSERT (yyp->yystate.yyisState);
-          YYASSERT (yyp->yyoption.yyisState);
-          YYFPRINTF (stderr, "Res: %d, LR State: %d, posn: %ld, pred: %ld",
-                     yyp->yystate.yyresolved, yyp->yystate.yylrState,
-                     YY_CAST (long, yyp->yystate.yyposn),
-                     YYINDEX (yyp->yystate.yypred));
+          YY_ASSERT (yyp->yystate.yyisState);
+          YY_ASSERT (yyp->yyoption.yyisState);
+          YY_FPRINTF ((stderr, "Res: %d, LR State: %d, posn: %ld, pred: %ld",
+                       yyp->yystate.yyresolved, yyp->yystate.yylrState,
+                       YY_CAST (long, yyp->yystate.yyposn),
+                       YYINDEX (yyp->yystate.yypred)));
          if (! yyp->yystate.yyresolved)
-            YYFPRINTF (stderr, ", firstVal: %ld",
-                       YYINDEX (yyp->yystate.yysemantics.yyfirstVal));
+            YY_FPRINTF ((stderr, ", firstVal: %ld",
+                         YYINDEX (yyp->yystate.yysemantics.yyfirstVal)));
        }
      else
        {
-          YYASSERT (!yyp->yystate.yyisState);
-          YYASSERT (!yyp->yyoption.yyisState);
-          YYFPRINTF (stderr, "Option. rule: %d, state: %ld, next: %ld",
-                     yyp->yyoption.yyrule - 1,
-                     YYINDEX (yyp->yyoption.yystate),
-                     YYINDEX (yyp->yyoption.yynext));
+          YY_ASSERT (!yyp->yystate.yyisState);
+          YY_ASSERT (!yyp->yyoption.yyisState);
+          YY_FPRINTF ((stderr, "Option. rule: %d, state: %ld, next: %ld",
+                       yyp->yyoption.yyrule - 1,
+                       YYINDEX (yyp->yyoption.yystate),
+                       YYINDEX (yyp->yyoption.yynext)));
        }
-      YYFPRINTF (stderr, "\n");
+      YY_FPRINTF ((stderr, "\n"));
    }

-  YYFPRINTF (stderr, "Tops:");
+  YY_FPRINTF ((stderr, "Tops:"));
  {
    ptrdiff_t yyi;
    for (yyi = 0; yyi < yystackp->yytops.yysize; yyi += 1)
-      YYFPRINTF (stderr, "%ld: %ld; ", YY_CAST (long, yyi),
-                 YYINDEX (yystackp->yytops.yystates[yyi]));
-    YYFPRINTF (stderr, "\n");
+      YY_FPRINTF ((stderr, "%ld: %ld; ", YY_CAST (long, yyi),
+                   YYINDEX (yystackp->yytops.yystates[yyi])));
+    YY_FPRINTF ((stderr, "\n"));
  }
 #undef YYINDEX
 }
@@ -265,6 +265,12 @@ b4_percent_code_get([[requires]])[
 # pragma GCC diagnostic ignored "-Wold-style-cast"
 #endif

+// On MacOS, PTRDIFF_MAX is defined as long long, which Clang's
+// -pedantic reports as being a C++11 extension.
+#if defined __APPLE__ && YY_CPLUSPLUS < 201103L && 4 <= __clang_major__
+# pragma clang diagnostic ignored "-Wc++11-long-long"
+#endif
+
 // Whether we are compiled with exception support.
 #ifndef YY_EXCEPTIONS
 # if defined __GNUC__ && !defined __EXCEPTIONS
@@ -268,7 +268,9 @@ m4_define([b4_shared_declarations],
    static const ]b4_int_type(b4_table_ninf, b4_table_ninf)[ yytable_ninf_;

    /// Convert a scanner token number \a t to a symbol number.
-    static token_number_type yytranslate_ (]b4_token_ctor_if([token_type], [int])[ t);
+    /// In theory \a t should be a token_type, but character literals
+    /// are valid, yet not members of the token_type enum.
+    static token_number_type yytranslate_ (int t);

    // Tables.
 ]b4_parser_tables_declare[]b4_error_verbose_if([
@@ -333,7 +335,8 @@ m4_define([b4_shared_declarations],
      symbol_number_type type_get () const YY_NOEXCEPT;

      /// The state number used to denote an empty symbol.
-      enum { empty_state = -1 };
+      /// We use the initial state, as it does not have a value.
+      enum { empty_state = 0 };

      /// The state.
      /// \a empty when empty.
@@ -397,6 +400,10 @@ m4_define([b4_shared_declarations],
    /// Pop \a n symbols from the stack.
    void yypop_ (int n = 1);

+    /// Some specific tokens.
+    static const token_number_type yy_error_token_ = 1;
+    static const token_number_type yy_undef_token_ = ]b4_undef_token_number[;
+
    /// Constants.
    enum
    {
@@ -404,8 +411,6 @@ m4_define([b4_shared_declarations],
      yylast_ = ]b4_last[,     ///< Last index in yytable_.
      yynnts_ = ]b4_nterms_number[,  ///< Number of nonterminal symbols.
      yyfinal_ = ]b4_final_state_number[, ///< Termination state number.
-      yyterror_ = 1,
-      yyerrcode_ = 256,
      yyntokens_ = ]b4_tokens_number[  ///< Number of tokens.
    };

@@ -1055,8 +1060,8 @@ b4_dollar_popdef])[]dnl
          yyn = yypact_[yystack_[0].state];
          if (!yy_pact_value_is_default_ (yyn))
            {
-              yyn += yyterror_;
-              if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == yyterror_)
+              yyn += yy_error_token_;
+              if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == yy_error_token_)
                {
                  yyn = yytable_[yyn];
                  if (0 < yyn)
@@ -1330,7 +1335,7 @@ b4_error_verbose_if([state_type yystate, const symbol_type& yyla],
    */
    if (!yyla.empty ())
      {
-        int yytoken = yyla.type_get ();
+        symbol_number_type yytoken = yyla.type_get ();
        yyarg[yycount++] = yytname_[yytoken];]b4_lac_if([[

 #if ]b4_api_PREFIX[DEBUG
@@ -1344,7 +1349,8 @@ b4_error_verbose_if([state_type yystate, const symbol_type& yyla],
        if (!yy_pact_value_is_default_ (yyn))
          {]b4_lac_if([[
            for (int yyx = 0; yyx < yyntokens_; ++yyx)
-              if (yyx != yyterror_ && yy_lac_check_(yyx))
+              if (yyx != yy_error_token_ && yyx != yy_undef_token_
+                  && yy_lac_check_ (yyx))
                {]], [[
            /* Start YYX at -YYN if negative to avoid negative indexes in
               YYCHECK.  In other words, skip the first -YYN actions for
@@ -1354,7 +1360,7 @@ b4_error_verbose_if([state_type yystate, const symbol_type& yyla],
            int yychecklim = yylast_ - yyn + 1;
            int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
            for (int yyx = yyxbegin; yyx < yyxend; ++yyx)
-              if (yycheck_[yyx + yyn] == yyx && yyx != yyterror_
+              if (yycheck_[yyx + yyn] == yyx && yyx != yy_error_token_
                  && !yy_table_value_is_error_ (yytable_[yyx + yyn]))
                {]])[
                  if (yycount == YYERROR_VERBOSE_ARGS_MAXIMUM)
@@ -187,9 +187,6 @@ b4_user_union_members
 {
  ]b4_identification[

-  /** True if verbose error messages are enabled.  */
-  public bool errorVerbose = ]b4_flag_value([error_verbose])[;
-
 ]b4_locations_if([[
  private final ]b4_location_type[ yylloc_from_stack (ref YYStack rhs, int n)
  {
@@ -400,7 +397,8 @@ b4_user_union_members
    ref ]b4_yystype[ yyvaluep]dnl
 b4_locations_if([, ref ]b4_location_type[ yylocationp])[)
  {
-    if (0 < yydebug) {
+    if (0 < yydebug)
+    {
      string message = s ~ (yytype < yyntokens_ ? " token " : " nterm ")
              ~ yytname_[yytype] ~ " ("]b4_locations_if([
              ~ yylocationp.toString() ~ ": "])[;
@@ -619,8 +617,8 @@ m4_popdef([b4_at_dollar])])dnl
          yyn = yypact_[yystate];
          if (!yy_pact_value_is_default_ (yyn))
          {
-            yyn += yyterror_;
-            if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == yyterror_)
+            yyn += yy_error_token_;
+            if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == yy_error_token_)
            {
              yyn = yytable_[yyn];
              if (0 < yyn)
@@ -667,78 +665,74 @@ m4_popdef([b4_at_dollar])])dnl

  // Generate an error message.
  private final string yysyntax_error (int yystate, int tok)
-  {
-    if (errorVerbose)
+  {]b4_error_verbose_if([[
+    /* There are many possibilities here to consider:
+       - Assume YYFAIL is not used.  It's too flawed to consider.
+         See
+         <http://lists.gnu.org/archive/html/bison-patches/2009-12/msg00024.html>
+         for details.  YYERROR is fine as it does not invoke this
+         function.
+       - If this state is a consistent state with a default action,
+         then the only way this function was invoked is if the
+         default action is an error action.  In that case, don't
+         check for expected tokens because there are none.
+       - The only way there can be no lookahead present (in tok) is
+         if this state is a consistent state with a default action.
+         Thus, detecting the absence of a lookahead is sufficient to
+         determine that there is no unexpected or expected token to
+         report.  In that case, just report a simple "syntax error".
+       - Don't assume there isn't a lookahead just because this
+         state is a consistent state with a default action.  There
+         might have been a previous inconsistent state, consistent
+         state with a non-default action, or user semantic action
+         that manipulated yychar.  (However, yychar is currently out
+         of scope during semantic actions.)
+       - Of course, the expected token list depends on states to
+         have correct lookahead information, and it depends on the
+         parser not to perform extra reductions after fetching a
+         lookahead from the scanner and before detecting a syntax
+         error.  Thus, state merging (from LALR or IELR) and default
+         reductions corrupt the expected token list.  However, the
+         list is correct for canonical LR with one exception: it
+         will still contain any token that will not be accepted due
+         to an error action in a later state.
+      */
+    if (tok != yyempty_)
    {
-      /* There are many possibilities here to consider:
-         - Assume YYFAIL is not used.  It's too flawed to consider.
-           See
-           <http://lists.gnu.org/archive/html/bison-patches/2009-12/msg00024.html>
-           for details.  YYERROR is fine as it does not invoke this
-           function.
-         - If this state is a consistent state with a default action,
-           then the only way this function was invoked is if the
-           default action is an error action.  In that case, don't
-           check for expected tokens because there are none.
-         - The only way there can be no lookahead present (in tok) is
-           if this state is a consistent state with a default action.
-           Thus, detecting the absence of a lookahead is sufficient to
-           determine that there is no unexpected or expected token to
-           report.  In that case, just report a simple "syntax error".
-         - Don't assume there isn't a lookahead just because this
-           state is a consistent state with a default action.  There
-           might have been a previous inconsistent state, consistent
-           state with a non-default action, or user semantic action
-           that manipulated yychar.  (However, yychar is currently out
-           of scope during semantic actions.)
-         - Of course, the expected token list depends on states to
-           have correct lookahead information, and it depends on the
-           parser not to perform extra reductions after fetching a
-           lookahead from the scanner and before detecting a syntax
-           error.  Thus, state merging (from LALR or IELR) and default
-           reductions corrupt the expected token list.  However, the
-           list is correct for canonical LR with one exception: it
-           will still contain any token that will not be accepted due
-           to an error action in a later state.
-        */
-      if (tok != yyempty_)
+      // FIXME: This method of building the message is not compatible
+      // with internationalization.
+      string res = "syntax error, unexpected ";
+      res ~= yytnamerr_ (yytname_[tok]);
+      int yyn = yypact_[yystate];
+      if (!yy_pact_value_is_default_ (yyn))
      {
-        // FIXME: This method of building the message is not compatible
-        // with internationalization.
-        string res = "syntax error, unexpected ";
-        res ~= yytnamerr_ (yytname_[tok]);
-        int yyn = yypact_[yystate];
-        if (!yy_pact_value_is_default_ (yyn))
-        {
-          /* Start YYX at -YYN if negative to avoid negative
-             indexes in YYCHECK.  In other words, skip the first
-             -YYN actions for this state because they are default
-             actions.  */
-          int yyxbegin = yyn < 0 ? -yyn : 0;
-          /* Stay within bounds of both yycheck and yytname.  */
-          int yychecklim = yylast_ - yyn + 1;
-          int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
-          int count = 0;
-          for (int x = yyxbegin; x < yyxend; ++x)
-            if (yycheck_[x + yyn] == x && x != yyterror_
-                && !yy_table_value_is_error_ (yytable_[x + yyn]))
-               ++count;
-            if (count < 5)
-            {
-               count = 0;
-               for (int x = yyxbegin; x < yyxend; ++x)
-                 if (yycheck_[x + yyn] == x && x != yyterror_
-                     && !yy_table_value_is_error_ (yytable_[x + yyn]))
-                 {
-                    res ~= count++ == 0 ? ", expecting " : " or ";
-                    res ~= yytnamerr_ (yytname_[x]);
-                 }
-            }
-        }
-        return res;
+        /* Start YYX at -YYN if negative to avoid negative
+           indexes in YYCHECK.  In other words, skip the first
+           -YYN actions for this state because they are default
+           actions.  */
+        int yyxbegin = yyn < 0 ? -yyn : 0;
+        /* Stay within bounds of both yycheck and yytname.  */
+        int yychecklim = yylast_ - yyn + 1;
+        int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
+        int count = 0;
+        for (int x = yyxbegin; x < yyxend; ++x)
+          if (yycheck_[x + yyn] == x && x != yy_error_token_
+              && !yy_table_value_is_error_ (yytable_[x + yyn]))
+             ++count;
+          if (count < 5)
+          {
+             count = 0;
+             for (int x = yyxbegin; x < yyxend; ++x)
+               if (yycheck_[x + yyn] == x && x != yy_error_token_
+                   && !yy_table_value_is_error_ (yytable_[x + yyn]))
+               {
+                  res ~= count++ == 0 ? ", expecting " : " or ";
+                  res ~= yytnamerr_ (yytname_[x]);
+               }
+          }
      }
-    }
-
+      return res;
+    }]])[
    return "syntax error";
  }

@@ -771,14 +765,6 @@ m4_popdef([b4_at_dollar])])dnl

  ]b4_parser_tables_define[

-  /* TOKEN_NUMBER_[YYLEX-NUM] -- Internal symbol number corresponding
-     to YYLEX-NUM.  */
-  private static immutable ]b4_int_type_for([b4_toknum])[[]
-  yytoken_number_ =
-  @{
-  ]b4_toknum[
-  @};
-
  /* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
     First, the terminals, then, starting at \a yyntokens_, nonterminals.  */
  private static immutable string[] yytname_ =
@@ -814,36 +800,38 @@ m4_popdef([b4_at_dollar])])dnl
  }
 ]])[

-  private static ]b4_int_type_for([b4_translate])[ yytranslate_ (int t)
+  private static token_number_type yytranslate_ (int t)
  {
 ]b4_api_token_raw_if(
 [[    import std.conv : to;
    return to!byte (t);]],
 [[    /* YYTRANSLATE(YYLEX) -- Bison symbol number corresponding to YYLEX.  */
-    immutable ]b4_int_type_for([b4_translate])[[] translate_table =
+    immutable token_number_type[] translate_table =
    @{
  ]b4_translate[
    @};

+    immutable int user_token_number_max_ = ]b4_user_token_number_max[;
+    immutable token_number_type undef_token_ = ]b4_undef_token_number[;
+
    if (t <= 0)
      return YYTokenType.EOF;
-    else if (t <= yyuser_token_number_max_)
+    else if (t <= user_token_number_max_)
      return translate_table[t];
    else
-      return yyundef_token_;]])[
+      return undef_token_;]])[
  }

+  alias ]b4_int_type_for([b4_translate])[ token_number_type;
+
+  private static immutable token_number_type yy_error_token_ = 1;
+
  private static immutable int yylast_ = ]b4_last[;
  private static immutable int yynnts_ = ]b4_nterms_number[;
  private static immutable int yyempty_ = -2;
  private static immutable int yyfinal_ = ]b4_final_state_number[;
-  private static immutable int yyterror_ = 1;
-  private static immutable int yyerrcode_ = 256;
  private static immutable int yyntokens_ = ]b4_tokens_number[;

-  private static immutable int yyuser_token_number_max_ = ]b4_user_token_number_max[;
-  private static immutable int yyundef_token_ = ]b4_undef_token_number[;
-
  private final struct YYStackElement {
    int state;
    ]b4_yystype[ value;]b4_locations_if(
@@ -751,8 +751,8 @@ b4_dollar_popdef[]dnl
            yyn = yypact_[yystate];
            if (!yyPactValueIsDefault (yyn))
              {
-                yyn += yyterror_;
-                if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == yyterror_)
+                yyn += yy_error_token_;
+                if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == yy_error_token_)
                  {
                    yyn = yytable_[yyn];
                    if (0 < yyn)
@@ -931,14 +931,14 @@ b4_dollar_popdef[]dnl
                int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
                int count = 0;
                for (int x = yyxbegin; x < yyxend; ++x)
-                  if (yycheck_[x + yyn] == x && x != yyterror_
+                  if (yycheck_[x + yyn] == x && x != yy_error_token_
                      && !yyTableValueIsError (yytable_[x + yyn]))
                    ++count;
                if (count < 5)
                  {
                    count = 0;
                    for (int x = yyxbegin; x < yyxend; ++x)
-                      if (yycheck_[x + yyn] == x && x != yyterror_
+                      if (yycheck_[x + yyn] == x && x != yy_error_token_
                          && !yyTableValueIsError (yytable_[x + yyn]))
                        {
                          res.append (count++ == 0 ? ", expecting " : " or ");
@@ -976,9 +976,6 @@ b4_dollar_popdef[]dnl
  private static final ]b4_int_type_for([b4_table])[ yytable_ninf_ = ]b4_table_ninf[;

  ]b4_parser_tables_define[
-  ]b4_integral_parser_table_define([token_number], [b4_toknum],
-     [[YYTOKEN_NUMBER[YYLEX-NUM] -- Internal symbol number corresponding
-   to YYLEX-NUM.]])[

  /* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
     First, the terminals, then, starting at \a yyntokens_, nonterminals.  */
@@ -1018,27 +1015,27 @@ b4_dollar_popdef[]dnl
  }
 ]],
 [[  {
+    int user_token_number_max_ = ]b4_user_token_number_max[;
+    ]b4_int_type_for([b4_translate])[ undef_token_ = ]b4_undef_token_number[;
+
    if (t <= 0)
      return Lexer.EOF;
-    else if (t <= yyuser_token_number_max_)
+    else if (t <= user_token_number_max_)
      return yytranslate_table_[t];
    else
-      return yyundef_token_;
+      return undef_token_;
  }
  ]b4_integral_parser_table_define([translate_table], [b4_translate])[
 ]])[

+  private static final ]b4_int_type_for([b4_translate])[ yy_error_token_ = 1;
+
  private static final int yylast_ = ]b4_last[;
  private static final int yynnts_ = ]b4_nterms_number[;
  private static final int yyempty_ = -2;
  private static final int yyfinal_ = ]b4_final_state_number[;
-  private static final int yyterror_ = 1;
-  private static final int yyerrcode_ = 256;
  private static final int yyntokens_ = ]b4_tokens_number[;

-  private static final int yyuser_token_number_max_ = ]b4_user_token_number_max[;
-  private static final int yyundef_token_ = ]b4_undef_token_number[;
-
 /* User implementation code.  */
 ]b4_percent_code_get[]dnl

@@ -72,9 +72,9 @@ m4_map([      b4_symbol_tag_comment], [$@])dnl
 # The needed includes for variants support.
 m4_define([b4_variant_includes],
 [b4_parse_assert_if([[#include <typeinfo>]])[
-#ifndef YYASSERT
+#ifndef YY_ASSERT
 # include <cassert>
-# define YYASSERT assert
+# define YY_ASSERT assert
 #endif
 ]])

@@ -111,14 +111,14 @@ m4_define([b4_value_type_declare],
    semantic_type (YY_RVREF (T) t)]b4_parse_assert_if([
      : yytypeid_ (&typeid (T))])[
    {
-      YYASSERT (sizeof (T) <= size);
+      YY_ASSERT (sizeof (T) <= size);
      new (yyas_<T> ()) T (YY_MOVE (t));
    }

    /// Destruction, allowed only if empty.
    ~semantic_type () YY_NOEXCEPT
    {]b4_parse_assert_if([
-      YYASSERT (!yytypeid_);
+      YY_ASSERT (!yytypeid_);
    ])[}

 # if 201103L <= YY_CPLUSPLUS
@@ -127,8 +127,8 @@ m4_define([b4_value_type_declare],
    T&
    emplace (U&&... u)
    {]b4_parse_assert_if([
-      YYASSERT (!yytypeid_);
-      YYASSERT (sizeof (T) <= size);
+      YY_ASSERT (!yytypeid_);
+      YY_ASSERT (sizeof (T) <= size);
      yytypeid_ = & typeid (T);])[
      return *new (yyas_<T> ()) T (std::forward <U>(u)...);
    }
@@ -138,8 +138,8 @@ m4_define([b4_value_type_declare],
    T&
    emplace ()
    {]b4_parse_assert_if([
-      YYASSERT (!yytypeid_);
-      YYASSERT (sizeof (T) <= size);
+      YY_ASSERT (!yytypeid_);
+      YY_ASSERT (sizeof (T) <= size);
      yytypeid_ = & typeid (T);])[
      return *new (yyas_<T> ()) T ();
    }
@@ -149,8 +149,8 @@ m4_define([b4_value_type_declare],
    T&
    emplace (const T& t)
    {]b4_parse_assert_if([
-      YYASSERT (!yytypeid_);
-      YYASSERT (sizeof (T) <= size);
+      YY_ASSERT (!yytypeid_);
+      YY_ASSERT (sizeof (T) <= size);
      yytypeid_ = & typeid (T);])[
      return *new (yyas_<T> ()) T (t);
    }
@@ -179,9 +179,9 @@ m4_define([b4_value_type_declare],
    T&
    as () YY_NOEXCEPT
    {]b4_parse_assert_if([
-      YYASSERT (yytypeid_);
-      YYASSERT (*yytypeid_ == typeid (T));
-      YYASSERT (sizeof (T) <= size);])[
+      YY_ASSERT (yytypeid_);
+      YY_ASSERT (*yytypeid_ == typeid (T));
+      YY_ASSERT (sizeof (T) <= size);])[
      return *yyas_<T> ();
    }

@@ -190,9 +190,9 @@ m4_define([b4_value_type_declare],
    const T&
    as () const YY_NOEXCEPT
    {]b4_parse_assert_if([
-      YYASSERT (yytypeid_);
-      YYASSERT (*yytypeid_ == typeid (T));
-      YYASSERT (sizeof (T) <= size);])[
+      YY_ASSERT (yytypeid_);
+      YY_ASSERT (*yytypeid_ == typeid (T));
+      YY_ASSERT (sizeof (T) <= size);])[
      return *yyas_<T> ();
    }

@@ -208,8 +208,8 @@ m4_define([b4_value_type_declare],
    void
    swap (self_type& that) YY_NOEXCEPT
    {]b4_parse_assert_if([
-      YYASSERT (yytypeid_);
-      YYASSERT (*yytypeid_ == *that.yytypeid_);])[
+      YY_ASSERT (yytypeid_);
+      YY_ASSERT (*yytypeid_ == *that.yytypeid_);])[
      std::swap (as<T> (), that.as<T> ());
    }

@@ -401,7 +401,7 @@ m4_define([_b4_token_constructor_define],
                              b4_symbol_if([$1], [has_type], [std::move (v)]),
                              b4_locations_if([std::move (l)]))[)
      {
-        YYASSERT (]m4_join([ || ], m4_map_sep([_b4_type_clause], [, ], [$@]))[);
+        YY_ASSERT (]m4_join([ || ], m4_map_sep([_b4_type_clause], [, ], [$@]))[);
      }
 #else
      symbol_type (]b4_join(
@@ -413,7 +413,7 @@ m4_define([_b4_token_constructor_define],
                              b4_symbol_if([$1], [has_type], [v]),
                              b4_locations_if([l]))[)
      {
-        YYASSERT (]m4_join([ || ], m4_map_sep([_b4_type_clause], [, ], [$@]))[);
+        YY_ASSERT (]m4_join([ || ], m4_map_sep([_b4_type_clause], [, ], [$@]))[);
      }
 #endif
 ]])])
@@ -854,8 +854,10 @@ yy_lac_stack_realloc (YYPTRDIFF_T *yycapacity, YYPTRDIFF_T yyadd,
      *yybottom = yybottom_new;
      *yycapacity = yyalloc;]m4_if(b4_percent_define_get([[parse.lac.memory-trace]]),
                                   [full], [[
+      YY_IGNORE_USELESS_CAST_BEGIN
      YYDPRINTF ((stderr, "%srealloc to %ld%s", yydebug_prefix,
-                  YY_CAST (long, yyalloc), yydebug_suffix));]])[
+                  YY_CAST (long, yyalloc), yydebug_suffix));
+      YY_IGNORE_USELESS_CAST_END]])[
    }
  return 0;
 }
@@ -1012,7 +1014,9 @@ yy_lac (yy_state_t *yyesa, yy_state_t **yyes,
        if (yyesp == yyes_prev)
          {
            yyesp = *yyes;
+            YY_IGNORE_USELESS_CAST_BEGIN
            *yyesp = YY_CAST (yy_state_t, yystate);
+            YY_IGNORE_USELESS_CAST_END
          }
        else
          {
@@ -1025,7 +1029,9 @@ yy_lac (yy_state_t *yyesa, yy_state_t **yyes,
                YYDPRINTF ((stderr, "\n"));
                return 2;
              }
+            YY_IGNORE_USELESS_CAST_BEGIN
            *++yyesp = YY_CAST (yy_state_t, yystate);
+            YY_IGNORE_USELESS_CAST_END
          }
        YYDPRINTF ((stderr, " G%d", yystate));
      }
@@ -1137,16 +1143,16 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
                ]b4_lac_if([[yy_state_t *yyesa, yy_state_t **yyes,
                YYPTRDIFF_T *yyes_capacity, ]])[yy_state_t *yyssp, int yytoken)
 {
-  YYPTRDIFF_T yysize0 = yytnamerr (YY_NULLPTR, yytname[yytoken]);
-  YYPTRDIFF_T yysize = yysize0;
  enum { YYERROR_VERBOSE_ARGS_MAXIMUM = 5 };
  /* Internationalized format string. */
  const char *yyformat = YY_NULLPTR;
-  /* Arguments of yyformat. */
+  /* Arguments of yyformat: reported tokens (one for the "unexpected",
+     one per "expected"). */
  char const *yyarg[YYERROR_VERBOSE_ARGS_MAXIMUM];
-  /* Number of reported tokens (one for the "unexpected", one per
-     "expected"). */
+  /* Actual size of YYARG. */
  int yycount = 0;
+  /* Cumulated lengths of YYARG.  */
+  YYPTRDIFF_T yysize = 0;

  /* There are many possibilities here to consider:
     - If this state is a consistent state with a default action, then
@@ -1178,7 +1184,9 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
  */
  if (yytoken != YYEMPTY)
    {
-      int yyn = yypact[*yyssp];]b4_lac_if([[
+      int yyn = yypact[*yyssp];
+      YYPTRDIFF_T yysize0 = yytnamerr (YY_NULLPTR, yytname[yytoken]);
+      yysize = yysize0;]b4_lac_if([[
      YYDPRINTF ((stderr, "Constructing syntax error message\n"));]])[
      yyarg[yycount++] = yytname[yytoken];
      if (!yypact_value_is_default (yyn))
@@ -1217,8 +1225,8 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
                  }
                yyarg[yycount++] = yytname[yyx];
                {
-                  YYPTRDIFF_T yysize1 = yysize + yytnamerr (YY_NULLPTR,
-                                                            yytname[yyx]);
+                  YYPTRDIFF_T yysize1
+                    = yysize + yytnamerr (YY_NULLPTR, yytname[yyx]);
                  if (yysize <= yysize1 && yysize1 <= YYSTACK_ALLOC_MAXIMUM)
                    yysize = yysize1;
                  else
@@ -1249,7 +1257,9 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
    }

  {
-    YYPTRDIFF_T yysize1 = yysize + yystrlen (yyformat);
+    /* Don't count the "%s"s in the final size, but reserve room for
+       the terminator.  */
+    YYPTRDIFF_T yysize1 = yysize + (yystrlen (yyformat) - 2 * yycount) + 1;
    if (yysize <= yysize1 && yysize1 <= YYSTACK_ALLOC_MAXIMUM)
      yysize = yysize1;
    else
@@ -1279,8 +1289,8 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
        }
      else
        {
-          yyp++;
-          yyformat++;
+          ++yyp;
+          ++yyformat;
        }
  }
  return 0;
@@ -1488,7 +1498,9 @@ yynewstate:
 yysetstate:
  YYDPRINTF ((stderr, "Entering state %d\n", yystate));
  YY_ASSERT (0 <= yystate && yystate < YYNSTATES);
-   *yyssp = YY_CAST (yy_state_t, yystate);
+  YY_IGNORE_USELESS_CAST_BEGIN
+  *yyssp = YY_CAST (yy_state_t, yystate);
+  YY_IGNORE_USELESS_CAST_END

  if (yyss + yystacksize - 1 <= yyssp)
 #if !defined yyoverflow && !defined YYSTACK_RELOCATE
@@ -1548,8 +1560,10 @@ yysetstate:
      yyvsp = yyvs + yysize - 1;]b4_locations_if([
      yylsp = yyls + yysize - 1;])[

+      YY_IGNORE_USELESS_CAST_BEGIN
      YYDPRINTF ((stderr, "Stack size increased to %ld\n",
                  YY_CAST (long, yystacksize)));
+      YY_IGNORE_USELESS_CAST_END

      if (yyss + yystacksize - 1 <= yyssp)
        YYABORT;
@@ -367,9 +367,9 @@ Debugging Your Parser

 Tracing Your Parser

-* Enabling Traces::             Activating run-time trace support
-* Mfcalc Traces::               Extending @code{mfcalc} to support traces
-* The YYPRINT Macro::           Obsolete interface for semantic value reports
+* Enabling Traces::    Activating run-time trace support
+* Mfcalc Traces::      Extending @code{mfcalc} to support traces
+* The YYPRINT Macro::  Obsolete interface for semantic value reports

 Invoking Bison

@@ -2897,25 +2897,25 @@ of line.
@cindex Prologue
@cindex declarations

-The @var{Prologue} section contains macro definitions and declarations
-of functions and variables that are used in the actions in the grammar
-rules.  These are copied to the beginning of the parser implementation
-file so that they precede the definition of @code{yyparse}.  You can
-use @samp{#include} to get the declarations from a header file.  If
-you don't need any C declarations, you may omit the @samp{%@{} and
-@samp{%@}} delimiters that bracket this section.
+The @var{Prologue} section contains macro definitions and declarations of
+functions and variables that are used in the actions in the grammar rules.
+These are copied to the beginning of the parser implementation file so that
+they precede the definition of @code{yyparse}.  You can use @samp{#include}
+to get the declarations from a header file.  If you don't need any C
+declarations, you may omit the @samp{%@{} and @samp{%@}} delimiters that
+bracket this section.

-The @var{Prologue} section is terminated by the first occurrence
-of @samp{%@}} that is outside a comment, a string literal, or a
-character constant.
+The @var{Prologue} section is terminated by the first occurrence of
+@samp{%@}} that is outside a comment, a string literal, or a character
+constant.

 You may have more than one @var{Prologue} section, intermixed with the
-@var{Bison declarations}.  This allows you to have C and Bison
-declarations that refer to each other.  For example, the @code{%union}
-declaration may use types defined in a header file, and you may wish to
-prototype functions that take arguments of type @code{YYSTYPE}.  This
-can be done with two @var{Prologue} blocks, one before and one after the
-@code{%union} declaration.
+@var{Bison declarations}.  This allows you to have C and Bison declarations
+that refer to each other.  For example, the @code{%union} declaration may
+use types defined in a header file, and you may wish to prototype functions
+that take arguments of type @code{YYSTYPE}.  This can be done with two
+@var{Prologue} blocks, one before and one after the @code{%union}
+declaration.

@example
@group
@@ -2935,20 +2935,18 @@ can be done with two @var{Prologue} blocks, one before and one after the

@group
 %@{
-  static void print_token_value (FILE *, int, YYSTYPE);
-  #define YYPRINT(F, N, L) print_token_value (F, N, L)
+  static void print_token (enum yytokentype token, YYSTYPE val);
 %@}
@end group

@dots{}
@end example

-When in doubt, it is usually safer to put prologue code before all
-Bison declarations, rather than after.  For example, any definitions
-of feature test macros like @code{_GNU_SOURCE} or
-@code{_POSIX_C_SOURCE} should appear before all Bison declarations, as
-feature test macros can affect the behavior of Bison-generated
-@code{#include} directives.
+When in doubt, it is usually safer to put prologue code before all Bison
+declarations, rather than after.  For example, any definitions of feature
+test macros like @code{_GNU_SOURCE} or @code{_POSIX_C_SOURCE} should appear
+before all Bison declarations, as feature test macros can affect the
+behavior of Bison-generated @code{#include} directives.

@node Prologue Alternatives
@subsection Prologue Alternatives
@@ -2960,12 +2958,11 @@ feature test macros can affect the behavior of Bison-generated
@findex %code top

 The functionality of @var{Prologue} sections can often be subtle and
-inflexible.  As an alternative, Bison provides a @code{%code}
-directive with an explicit qualifier field, which identifies the
-purpose of the code and thus the location(s) where Bison should
-generate it.  For C/C++, the qualifier can be omitted for the default
-location, or it can be one of @code{requires}, @code{provides},
-@code{top}.  @xref{%code Summary}.
+inflexible.  As an alternative, Bison provides a @code{%code} directive with
+an explicit qualifier field, which identifies the purpose of the code and
+thus the location(s) where Bison should generate it.  For C/C++, the
+qualifier can be omitted for the default location, or it can be one of
+@code{requires}, @code{provides}, @code{top}.  @xref{%code Summary}.

 Look again at the example of the previous section:

@@ -2987,8 +2984,7 @@ Look again at the example of the previous section:

@group
 %@{
-  static void print_token_value (FILE *, int, YYSTYPE);
-  #define YYPRINT(F, N, L) print_token_value (F, N, L)
+  static void print_token (enum yytokentype token, YYSTYPE val);
 %@}
@end group

@@ -3050,8 +3046,7 @@ the same time:

@group
 %code @{
-  static void print_token_value (FILE *, int, YYSTYPE);
-  #define YYPRINT(F, N, L) print_token_value (F, N, L)
+  static void print_token (enum yytokentype token, YYSTYPE val);
  static void trace_token (enum yytokentype token, YYLTYPE loc);
@}
@end group
@@ -3060,21 +3055,20 @@ the same time:
@end example

@noindent
-In this way, @code{%code top} and the unqualified @code{%code} achieve the same
-functionality as the two kinds of @var{Prologue} sections, but it's always
-explicit which kind you intend.
-Moreover, both kinds are always available even in the absence of @code{%union}.
+In this way, @code{%code top} and the unqualified @code{%code} achieve the
+same functionality as the two kinds of @var{Prologue} sections, but it's
+always explicit which kind you intend.  Moreover, both kinds are always
+available even in the absence of @code{%union}.

-The @code{%code top} block above logically contains two parts.  The
-first two lines before the warning need to appear near the top of the
-parser implementation file.  The first line after the warning is
-required by @code{YYSTYPE} and thus also needs to appear in the parser
-implementation file.  However, if you've instructed Bison to generate
-a parser header file (@pxref{Decl Summary, ,%defines}), you probably
-want that line to appear before the @code{YYSTYPE} definition in that
-header file as well.  The @code{YYLTYPE} definition should also appear
-in the parser header file to override the default @code{YYLTYPE}
-definition there.
+The @code{%code top} block above logically contains two parts.  The first
+two lines before the warning need to appear near the top of the parser
+implementation file.  The first line after the warning is required by
+@code{YYSTYPE} and thus also needs to appear in the parser implementation
+file.  However, if you've instructed Bison to generate a parser header file
+(@pxref{Decl Summary, ,%defines}), you probably want that line to appear
+before the @code{YYSTYPE} definition in that header file as well.  The
+@code{YYLTYPE} definition should also appear in the parser header file to
+override the default @code{YYLTYPE} definition there.

 In other words, in the @code{%code top} block above, all but the first two
 lines are dependency code required by the @code{YYSTYPE} and @code{YYLTYPE}
@@ -3117,8 +3111,7 @@ Thus, they belong in one or more @code{%code requires}:

@group
 %code @{
-  static void print_token_value (FILE *, int, YYSTYPE);
-  #define YYPRINT(F, N, L) print_token_value (F, N, L)
+  static void print_token (enum yytokentype token, YYSTYPE val);
  static void trace_token (enum yytokentype token, YYLTYPE loc);
@}
@end group
@@ -3197,8 +3190,7 @@ unqualified @code{%code} to a @code{%code provides}:

@group
 %code @{
-  static void print_token_value (FILE *, int, YYSTYPE);
-  #define YYPRINT(F, N, L) print_token_value (F, N, L)
+  static void print_token (FILE *file, int token, YYSTYPE val);
@}
@end group

@@ -6494,9 +6486,12 @@ Obsoleted by @code{api.namespace}
@deffn Directive {%define parse.assert}

@itemize
-@item Languages(s): C++
+@item Languages(s): C, C++

@item Purpose: Issue runtime assertions to catch invalid uses.
+In C, some important invariants in the implementation of the parser are
+checked when this option is enabled.
+
 In C++, when variants are used (@pxref{C++ Variants}), symbols must be
 constructed and destroyed properly.  This option checks these constraints.

@@ -10069,9 +10064,7 @@ of variables show where in the grammar it is working.
 The debugging information normally gives the token type of each token read,
 but not its semantic value.  The @code{%printer} directive allows specify
 how semantic values are reported, see @ref{Printer Decl, , Printing
-Semantic Values}.  For backward compatibility, Yacc like C parsers may also
-use the @code{YYPRINT} (@pxref{The YYPRINT Macro, , The @code{YYPRINT}
-Macro}), but its use is discouraged.
+Semantic Values}.

 As a demonstration of @code{%printer}, consider the multi-function
 calculator, @code{mfcalc} (@pxref{Multi-function Calc}).  To enable run-time
@@ -10234,14 +10227,16 @@ Cleanup: popping nterm input ()

@node The YYPRINT Macro
@subsection The @code{YYPRINT} Macro
-
@findex YYPRINT
-Before @code{%printer} support, semantic values could be displayed using the
-@code{YYPRINT} macro, which works only for terminal symbols and only with
-the @file{yacc.c} skeleton.
+
+The @code{%printer} directive was introduced in Bison 1.50 (Novembre 2002).
+Before then, @code{YYPRINT} provided a similar feature, but only for
+terminal symbols and only with the @file{yacc.c} skeleton.

@deffn {Macro} YYPRINT (@var{stream}, @var{token}, @var{value});
@findex YYPRINT
+Deprecated, will be removed eventually.
+
 If you define @code{YYPRINT}, it should take three arguments.  The parser
 will pass a standard I/O stream, the numeric code for the token type, and
 the token value (from @code{yylval}).
@@ -10254,7 +10249,7 @@ calculator (@pxref{Mfcalc Declarations, ,Declarations for @code{mfcalc}}):

@example
 %@{
-  static void print_token_value (FILE *, int, YYSTYPE);
+  static void print_token_value (FILE *file, int type, YYSTYPE value);
  #define YYPRINT(File, Type, Value)            \
    print_token_value (File, Type, Value)
 %@}
@@ -10271,6 +10266,9 @@ print_token_value (FILE *file, int type, YYSTYPE value)
@}
@end example

+@xref{Mfcalc Traces, ,Enabling Debug Traces for @code{mfcalc}}, for the
+proper use of @code{%printer}.
+
@c ================================================= Invoking Bison

@node Invocation
@@ -14232,7 +14230,8 @@ parsing.  @xref{Parser Function, ,The Parser Function @code{yyparse}}.

@deffn {Macro} YYPRINT
 Macro used to output token semantic values.  For @file{yacc.c} only.
-Obsoleted by @code{%printer}.
+Deprecated, use @code{%printer} instead (@pxref{Printer Decl, , Printing
+Semantic Values}).
@xref{The YYPRINT Macro, , The @code{YYPRINT} Macro}.
@end deffn

@@ -225,6 +225,7 @@ warnings_argmatch (char *args)
        }
 }

+/* Color style for this type of message.  */
 static const char*
 severity_style (severity s)
 {
@@ -242,6 +243,7 @@ severity_style (severity s)
  abort ();
 }

+/* Prefix for this type of message.  */
 static const char*
 severity_prefix (severity s)
 {
@@ -61,6 +61,7 @@ typedef enum
 /** Whether -Werror was set. */
 extern bool warnings_are_errors;

+/** Document --warning arguments.  */
 void warning_usage (FILE *out);

 /** Decode a single argument from -W.
@@ -99,6 +100,7 @@ void complain_free (void);
 /** Initialize support for colored messages.  */
 void complain_init_color (void);

+/** Flags passed to diagnostics functions.  */
 typedef enum
  {
    Wnone             = 0,       /**< Issue no warnings.  */
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.4.90.26-44cd.  */
+/* A Bison parser, made by GNU Bison 3.4.92.  */

 /* Bison implementation for Yacc-like parsers in C

@@ -48,7 +48,7 @@
 #define YYBISON 1

 /* Bison version.  */
-#define YYBISON_VERSION "3.4.90.26-44cd"
+#define YYBISON_VERSION "3.4.92"

 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -348,11 +348,11 @@ typedef int yy_state_fast_t;

 #if defined __GNUC__ && ! defined __ICC && 407 <= __GNUC__ * 100 + __GNUC_MINOR__
 /* Suppress an incorrect diagnostic about yylval being uninitialized.  */
-# define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN \
-    _Pragma ("GCC diagnostic push") \
-    _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"")\
+# define YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN                            \
+    _Pragma ("GCC diagnostic push")                                     \
+    _Pragma ("GCC diagnostic ignored \"-Wuninitialized\"")              \
    _Pragma ("GCC diagnostic ignored \"-Wmaybe-uninitialized\"")
-# define YY_IGNORE_MAYBE_UNINITIALIZED_END \
+# define YY_IGNORE_MAYBE_UNINITIALIZED_END      \
    _Pragma ("GCC diagnostic pop")
 #else
 # define YY_INITIAL_VALUE(Value) Value
@@ -365,6 +365,18 @@ typedef int yy_state_fast_t;
 # define YY_INITIAL_VALUE(Value) /* Nothing. */
 #endif

+#if defined __cplusplus && defined __GNUC__ && ! defined __ICC && 6 <= __GNUC__
+# define YY_IGNORE_USELESS_CAST_BEGIN                          \
+    _Pragma ("GCC diagnostic push")                            \
+    _Pragma ("GCC diagnostic ignored \"-Wuseless-cast\"")
+# define YY_IGNORE_USELESS_CAST_END            \
+    _Pragma ("GCC diagnostic pop")
+#endif
+#ifndef YY_IGNORE_USELESS_CAST_BEGIN
+# define YY_IGNORE_USELESS_CAST_BEGIN
+# define YY_IGNORE_USELESS_CAST_END
+#endif
+

 #define YY_ASSERT(E) ((void) (0 && (E)))

@@ -1410,7 +1422,9 @@ yy_lac (yy_state_t *yyesa, yy_state_t **yyes,
        if (yyesp == yyes_prev)
          {
            yyesp = *yyes;
+            YY_IGNORE_USELESS_CAST_BEGIN
            *yyesp = YY_CAST (yy_state_t, yystate);
+            YY_IGNORE_USELESS_CAST_END
          }
        else
          {
@@ -1423,7 +1437,9 @@ yy_lac (yy_state_t *yyesa, yy_state_t **yyes,
                YYDPRINTF ((stderr, "\n"));
                return 2;
              }
+            YY_IGNORE_USELESS_CAST_BEGIN
            *++yyesp = YY_CAST (yy_state_t, yystate);
+            YY_IGNORE_USELESS_CAST_END
          }
        YYDPRINTF ((stderr, " G%d", yystate));
      }
@@ -1535,16 +1551,16 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
                yy_state_t *yyesa, yy_state_t **yyes,
                YYPTRDIFF_T *yyes_capacity, yy_state_t *yyssp, int yytoken)
 {
-  YYPTRDIFF_T yysize0 = yytnamerr (YY_NULLPTR, yytname[yytoken]);
-  YYPTRDIFF_T yysize = yysize0;
  enum { YYERROR_VERBOSE_ARGS_MAXIMUM = 5 };
  /* Internationalized format string. */
  const char *yyformat = YY_NULLPTR;
-  /* Arguments of yyformat. */
+  /* Arguments of yyformat: reported tokens (one for the "unexpected",
+     one per "expected"). */
  char const *yyarg[YYERROR_VERBOSE_ARGS_MAXIMUM];
-  /* Number of reported tokens (one for the "unexpected", one per
-     "expected"). */
+  /* Actual size of YYARG. */
  int yycount = 0;
+  /* Cumulated lengths of YYARG.  */
+  YYPTRDIFF_T yysize = 0;

  /* There are many possibilities here to consider:
     - If this state is a consistent state with a default action, then
@@ -1569,6 +1585,8 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
  if (yytoken != YYEMPTY)
    {
      int yyn = yypact[*yyssp];
+      YYPTRDIFF_T yysize0 = yytnamerr (YY_NULLPTR, yytname[yytoken]);
+      yysize = yysize0;
      YYDPRINTF ((stderr, "Constructing syntax error message\n"));
      yyarg[yycount++] = yytname[yytoken];
      if (!yypact_value_is_default (yyn))
@@ -1594,8 +1612,8 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
                  }
                yyarg[yycount++] = yytname[yyx];
                {
-                  YYPTRDIFF_T yysize1 = yysize + yytnamerr (YY_NULLPTR,
-                                                            yytname[yyx]);
+                  YYPTRDIFF_T yysize1
+                    = yysize + yytnamerr (YY_NULLPTR, yytname[yyx]);
                  if (yysize <= yysize1 && yysize1 <= YYSTACK_ALLOC_MAXIMUM)
                    yysize = yysize1;
                  else
@@ -1626,7 +1644,9 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
    }

  {
-    YYPTRDIFF_T yysize1 = yysize + yystrlen (yyformat);
+    /* Don't count the "%s"s in the final size, but reserve room for
+       the terminator.  */
+    YYPTRDIFF_T yysize1 = yysize + (yystrlen (yyformat) - 2 * yycount) + 1;
    if (yysize <= yysize1 && yysize1 <= YYSTACK_ALLOC_MAXIMUM)
      yysize = yysize1;
    else
@@ -1656,8 +1676,8 @@ yysyntax_error (YYPTRDIFF_T *yymsg_alloc, char **yymsg,
        }
      else
        {
-          yyp++;
-          yyformat++;
+          ++yyp;
+          ++yyformat;
        }
  }
  return 0;
@@ -1857,7 +1877,9 @@ yynewstate:
 yysetstate:
  YYDPRINTF ((stderr, "Entering state %d\n", yystate));
  YY_ASSERT (0 <= yystate && yystate < YYNSTATES);
-   *yyssp = YY_CAST (yy_state_t, yystate);
+  YY_IGNORE_USELESS_CAST_BEGIN
+  *yyssp = YY_CAST (yy_state_t, yystate);
+  YY_IGNORE_USELESS_CAST_END

  if (yyss + yystacksize - 1 <= yyssp)
 #if !defined yyoverflow && !defined YYSTACK_RELOCATE
@@ -1917,8 +1939,10 @@ yysetstate:
      yyvsp = yyvs + yysize - 1;
      yylsp = yyls + yysize - 1;

+      YY_IGNORE_USELESS_CAST_BEGIN
      YYDPRINTF ((stderr, "Stack size increased to %ld\n",
                  YY_CAST (long, yystacksize)));
+      YY_IGNORE_USELESS_CAST_END

      if (yyss + yystacksize - 1 <= yyssp)
        YYABORT;
@@ -3040,9 +3064,9 @@ handle_require (location const *loc, char const *version)
      return;
    }

-  /* Pretend to be at least 3.4, to check features published in 3.4
-     while developping it.  */
-  const char* api_version = "3.4";
+  /* Pretend to be at least 3.5, to check features published in that
+     version while developping it.  */
+  const char* api_version = "3.5";
  const char* package_version =
    0 < strverscmp (api_version, PACKAGE_VERSION)
    ? api_version : PACKAGE_VERSION;
@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.4.90.26-44cd.  */
+/* A Bison parser, made by GNU Bison 3.4.92.  */

 /* Bison interface for Yacc-like parsers in C

@@ -1021,9 +1021,9 @@ handle_require (location const *loc, char const *version)
      return;
    }

-  /* Pretend to be at least 3.4, to check features published in 3.4
-     while developping it.  */
-  const char* api_version = "3.4";
+  /* Pretend to be at least 3.5, to check features published in that
+     version while developping it.  */
+  const char* api_version = "3.5";
  const char* package_version =
    0 < strverscmp (api_version, PACKAGE_VERSION)
    ? api_version : PACKAGE_VERSION;
@@ -209,22 +209,23 @@ at_basename (int argc, char *argv[], char **out_namep, int *out_linenop)
 static void
 at_complain (int argc, char *argv[], char **out_namep, int *out_linenop)
 {
-  static int indent;
-  warnings w = flag (argv[1]);
-  location loc;
-  location *locp = NULL;
+  if (argc < 4)
+    fail_for_at_directive_too_few_args (argv[0]);

  (void) out_namep;
  (void) out_linenop;

-  if (argc < 4)
-    fail_for_at_directive_too_few_args (argv[0]);
+  warnings w = flag (argv[1]);
+
+  location loc;
+  location *locp = NULL;
  if (argv[2] && argv[2][0])
    {
      boundary_set_from_string (&loc.start, argv[2]);
      boundary_set_from_string (&loc.end, argv[3]);
      locp = &loc;
    }
+  static int indent;
  if (w & silent)
    indent += SUB_INDENT;
  else
@@ -473,7 +473,7 @@ AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 ])

-## FIXME: test Java.
+## FIXME: test Java and D.
 m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc])

 m4_popdef([AT_TEST])
@@ -1780,7 +1780,7 @@ float: UNTYPED INT
                                 yy::parser::token::INT,
                                  EOF}]],
                               [[{UNTYPED, INT, EOF}]]),
-                 [AT_VAL.ival = YY_CAST (int, toknum) * 10;
+                 [AT_VAL.ival = toknum * 10;
                  AT_VAL.fval = YY_CAST (float, toknum) / 10.0f;])[
 ]AT_MAIN_DEFINE[
 ]])
@@ -1897,7 +1897,7 @@ exp:

 %%
 ]AT_YYERROR_DEFINE[
-]AT_YYLEX_DEFINE(["bcd"], [*lvalp = YY_CAST (int, (toknum + 1) * 10)])[
+]AT_YYLEX_DEFINE(["bcd"], [*lvalp = (toknum + 1) * 10])[
 ]AT_MAIN_DEFINE[
 ]])
 AT_BISON_OPTION_POPDEFS
@@ -117,9 +117,9 @@ fi
 : ${DC='@DC@'}
 : ${DCFLAGS='@DCFLAGS@'}
 if test x"$DC" = x; then
-    BISON_DC_WORKS=false
+  BISON_DC_WORKS=false
 else
-    BISON_DC_WORKS=true
+  BISON_DC_WORKS=true
 fi

 # Empty if no javac was found
@@ -1019,6 +1019,66 @@ input.y:12.3-18: warning: rule useless in parser due to conflicts [-Wother]
 AT_CLEANUP


+## ---------------------------------------- ##
+## Syntax error in consistent error state.  ##
+## ---------------------------------------- ##
+
+# AT_TEST(SKELETON-NAME)
+# ----------------------
+# Make sure yysyntax_error does nothing silly when called on yytoken
+# == YYEMPTY.
+
+m4_pushdef([AT_TEST],
+[AT_SETUP([Syntax error in consistent error state: $1])
+
+AT_BISON_OPTION_PUSHDEFS([%skeleton "$1"])
+
+AT_DATA_GRAMMAR([input.y],
+[[%define parse.error verbose
+%skeleton "$1"
+%%
+%nonassoc 'a';
+
+start: 'a' consistent-error-on-a-a 'a';
+
+consistent-error-on-a-a:
+    'a' default-reduction
+  | 'a' default-reduction 'a'
+  ;
+
+default-reduction: %empty;
+
+%code {
+  #include <stdio.h>
+  ]AT_YYERROR_DECLARE[
+  ]AT_YYLEX_DECLARE[
+};
+%%
+]AT_YYERROR_DEFINE[
+]AT_YYLEX_DEFINE("aa")[
+]AT_MAIN_DEFINE[
+]])
+
+AT_BISON_CHECK([-o input.AT_LANG_EXT input.y], 0, [],
+[[input.y:17.5-25: warning: rule useless in parser due to conflicts [-Wother]
+input.y:18.5-29: warning: rule useless in parser due to conflicts [-Wother]
+]])
+AT_LANG_COMPILE([input])
+AT_PARSER_CHECK([[input]], 1, [],
+[[syntax error
+]])
+
+AT_BISON_OPTION_POPDEFS
+AT_CLEANUP
+])
+
+## FIXME: test Java and D.
+m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc])
+
+m4_popdef([AT_TEST])
+
+
+
 ## -------------------------------- ##
 ## Defaulted Conflicted Reduction.  ##
 ## -------------------------------- ##
@@ -41,9 +41,9 @@ static YYSTYPE exprMerge (YYSTYPE x0, YYSTYPE x1);
 %}


+%define parse.assert
 %glr-parser

-
 /* -------- productions ------ */
 %%

@@ -128,6 +128,7 @@ AT_DATA_GRAMMAR([glr-regr2a.y],
  ]AT_YYLEX_DECLARE[
 %}

+%define parse.assert
 %glr-parser

 %%
@@ -265,6 +266,7 @@ static int MergeRule (int x0, int x1);

 %}

+%define parse.assert
 %glr-parser

 %token BAD_CHAR
@@ -370,6 +372,7 @@ AT_SETUP([Duplicate representation of merged trees])
 AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr4.y],
 [[
+%define parse.assert
 %union { char *ptr; }
 %type <ptr> S A A1 A2 B
 %glr-parser
@@ -469,6 +472,7 @@ AT_DATA_GRAMMAR([glr-regr5.y],
  enum { MAGIC_VALUE = -1057808125 }; /* originally chosen at random */
 %}

+%define parse.assert
 %glr-parser
 %union { int value; }
 %type <value> start
@@ -524,6 +528,7 @@ AT_DATA_GRAMMAR([glr-regr6.y],
  ]AT_YYLEX_DECLARE[
 %}

+%define parse.assert
 %glr-parser
 %union { int value; }
 %type <value> 'a'
@@ -580,6 +585,7 @@ AT_DATA_GRAMMAR([glr-regr7.y],
  static count_node *tail;
 %}

+%define parse.assert
 %glr-parser
 %union { count_node *node; }
 %type <node> 'a'
@@ -667,6 +673,7 @@ AT_DATA_GRAMMAR([glr-regr8.y],
 %token T_PORT
 %token T_SIGNAL

+%define parse.assert
 %glr-parser

 %%
@@ -756,6 +763,7 @@ AT_DATA_GRAMMAR([glr-regr9.y],
 # define USE(Var)
 %}

+%define parse.assert
 %glr-parser
 %union { int dummy; }
 %type <dummy> 'a'
@@ -831,6 +839,7 @@ AT_DATA_GRAMMAR([glr-regr10.y],
  static char garbage[GARBAGE_SIZE];
 %}

+%define parse.assert
 %glr-parser
 %union { char *ptr; }
 %type <ptr> start
@@ -884,6 +893,7 @@ AT_DATA_GRAMMAR([glr-regr11.y],
 # define USE(val)
 %}

+%define parse.assert
 %glr-parser
 %union { int dummy; }
 %type <int> 'a'
@@ -934,6 +944,7 @@ AT_SETUP([Leaked semantic values if user action cuts parse])
 AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr12.y],
 [[
+%define parse.assert
 %glr-parser
 %union { int dummy; }
 %token PARENT_RHS_AFTER
@@ -1073,6 +1084,7 @@ AT_DATA_GRAMMAR([glr-regr13.y],
  #define USE(value)
 %}

+%define parse.assert
 %union { char value; }
 %type <value> 'a' 'b'
 %glr-parser
@@ -1213,6 +1225,7 @@ AT_DATA_GRAMMAR([glr-regr14.y],
  #define USE(value)
 %}

+%define parse.assert
 %type <value> 'a' 'b' 'c' 'd' stack_explosion
 %glr-parser
 %locations
@@ -1397,6 +1410,7 @@ AT_SETUP([Leaked semantic values when reporting ambiguity])
 AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr15.y],
 [[
+%define parse.assert
 %glr-parser
 %destructor { parent_rhs_before_value = 0; } parent_rhs_before

@@ -1479,6 +1493,7 @@ AT_SETUP([Leaked lookahead after nondeterministic parse syntax error])
 AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr16.y],
 [[
+%define parse.assert
 %glr-parser
 %destructor { lookahead_value = 0; } 'b'

@@ -1540,6 +1555,7 @@ AT_BISON_OPTION_PUSHDEFS([%glr-parser %locations %define api.pure])

 AT_DATA_GRAMMAR([glr-regr17.y],
 [[
+%define parse.assert
 %glr-parser
 %locations
 %define api.pure
@@ -1612,7 +1628,8 @@ AT_SETUP([Missed %merge type warnings when LHS type is declared later])

 AT_BISON_OPTION_PUSHDEFS
 AT_DATA_GRAMMAR([glr-regr18.y],
-[[%glr-parser
+[[%define parse.assert
+%glr-parser

 %{
  #include <stdlib.h>
@@ -1625,7 +1642,6 @@ AT_DATA_GRAMMAR([glr-regr18.y],
  int type2;
  int type3;
 }
-
 %%

 sym1: sym2 %merge<merge> { $$ = $1; } ;
@@ -1661,14 +1677,14 @@ AT_SETUP([Ambiguity reports])

 AT_BISON_OPTION_PUSHDEFS([%debug])
 AT_DATA_GRAMMAR([input.y],
-[[
-%{
+[[%{
  #include <stdio.h>
  #include <stdlib.h>
  ]AT_YYERROR_DECLARE[
  ]AT_YYLEX_DECLARE[
 %}

+%define parse.assert
 %debug
 %glr-parser

@@ -1762,7 +1778,8 @@ AT_CLEANUP
 AT_SETUP([Predicates])

 AT_DATA_GRAMMAR([input.y],
-[[%glr-parser
+[[%define parse.assert
+%glr-parser
 %define parse.error verbose
 %expect-rr 1
 %code requires
@@ -326,7 +326,7 @@ AT_PERL_CHECK([[-n -0777 -e '
      |YY_CONSTEXPR
      |YY_COPY
      |YY_CPLUSPLUS
-      |YY_IGNORE_MAYBE_UNINITIALIZED_(?:BEGIN|END)
+      |YY_IGNORE_(?:MAYBE_UNINITIALIZED|USELESS_CAST)_(?:BEGIN|END)
      |YY_INITIAL_VALUE
      |YY_MOVE
      |YY_MOVE_OR_COPY
@@ -1199,7 +1199,7 @@ m4_ifval([$2],
 # Check that we can expect exceptions to be handled properly.
 # GCC 4.3 and 4.4 fail https://trac.macports.org/ticket/40853.
 m4_define([AT_SKIP_IF_EXCEPTION_SUPPORT_IS_POOR],
-[AT_DATA_SOURCE([exception.cc],
+[AT_DATA_SOURCE([exceptions.cc],
 [[#include <iostream>
 #include <stdexcept>

@@ -1230,10 +1230,9 @@ int main ()
  return 1;
 }
 ]])
-AT_COMPILE_CXX([exception])
-# The "empty" quadrigraph is to protect from cfg.mk's
-# sc_at_parser_check.
-AT_CHECK([@&t@./exception || exit 77], [0], [], [ignore])
+AT_COMPILE_CXX([exceptions])
+# The "empty" quadrigraph is to protect from cfg.mk's sc_at_parser_check.
+AT_CHECK([@&t@./exceptions || exit 77], [0], [], [ignore])
 ])


@@ -43,20 +43,51 @@ AT_YYLEX_PROTOTYPE[
    case '8':
    case '9':
      ]AT_VAL[.val = c - '0';
-      return ]AT_CXX_IF([yy::parser::token::])[NUM;
-    case '+': return ]AT_CXX_IF([yy::parser::token::])[PLUS;
-    case '-': return ]AT_CXX_IF([yy::parser::token::])[MINUS;
-    case '*': return ]AT_CXX_IF([yy::parser::token::])[STAR;
-    case '/': return ]AT_CXX_IF([yy::parser::token::])[SLASH;
-    case '(': return ]AT_CXX_IF([yy::parser::token::])[LPAR;
-    case ')': return ]AT_CXX_IF([yy::parser::token::])[RPAR;
-    case 0: return 0;
+      return NUM;
+    case '+': return PLUS;
+    case '-': return MINUS;
+    case '*': return STAR;
+    case '/': return SLASH;
+    case '(': return LPAR;
+    case ')': return RPAR;
+    case 0:   return 0;
    }
  abort ();
 }
 ]])

-m4_copy([AT_RAW_YYLEX(c)], [AT_RAW_YYLEX(c++)])
+m4_define([AT_RAW_YYLEX(c++)],
+[#include <stdlib.h> /* abort */
+AT_YYLEX_PROTOTYPE[
+{
+  static const char* input = "0-(1+2)*3/9";
+  int c = *input++;
+  switch (c)
+    {
+    case '0':
+    case '1':
+    case '2':
+    case '3':
+    case '4':
+    case '5':
+    case '6':
+    case '7':
+    case '8':
+    case '9':]AT_TOKEN_CTOR_IF([[
+      return yy::parser::make_NUM (c - '0');]], [[
+      ]AT_VAL[.val = c - '0';
+      return yy::parser::token::NUM;]])[
+    case '+': return yy::parser::]AT_TOKEN_CTOR_IF([make_PLUS ()],  [token::PLUS])[;
+    case '-': return yy::parser::]AT_TOKEN_CTOR_IF([make_MINUS ()], [token::MINUS])[;
+    case '*': return yy::parser::]AT_TOKEN_CTOR_IF([make_STAR ()],  [token::STAR])[;
+    case '/': return yy::parser::]AT_TOKEN_CTOR_IF([make_SLASH ()], [token::SLASH])[;
+    case '(': return yy::parser::]AT_TOKEN_CTOR_IF([make_LPAR ()],  [token::LPAR])[;
+    case ')': return yy::parser::]AT_TOKEN_CTOR_IF([make_RPAR ()],  [token::RPAR])[;
+    case 0:   return yy::parser::]AT_TOKEN_CTOR_IF([make_END ()],   [token::END])[;
+    }
+  abort ();
+}
+]])

 m4_define([AT_RAW_YYLEX(d)],
 [[import std.range.primitives;
@@ -147,10 +178,17 @@ AT_DATA_GRAMMAR([[input.y]],
 ]AT_YYLEX_DECLARE[
 }]])[

+]AT_VARIANT_IF([[
+%token <int> NUM "number"
+%nterm <int> exp
+]], [[
 %union {
  int val;
 }
 %token <val> NUM "number"
+%nterm <val> exp
+]])[
+
 %token
  PLUS  "+"
  MINUS "-"
@@ -158,7 +196,7 @@ AT_DATA_GRAMMAR([[input.y]],
  SLASH "/"
  LPAR  "("
  RPAR  ")"
-%nterm <val> exp
+  END   0

 %left "+" "-"
 %left "*" "/"
@@ -206,6 +244,7 @@ m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], [glr.cc], [lalr1.d]],
 [AT_TEST([%skeleton "]b4_skel["])
 AT_TEST([%skeleton "]b4_skel[" %define api.token.raw])])

+AT_TEST([%skeleton "lalr1.cc" %define api.token.raw %define api.value.type variant %define api.token.constructor])])

 m4_popdef([AT_MAIN_DEFINE(d)])
 m4_popdef([AT_TEST])
Author	SHA1	Message	Date
Akim Demaille	cb3bf6493d	version 3.5 * NEWS: Record release date.	2019-12-11 07:41:51 +01:00
Akim Demaille	57503e2165	news: prepare for 3.5	2019-12-10 07:06:04 +01:00
Akim Demaille	b3abe014f2	glr.cc: disable warnings from Clang on macOS $ cat test.cc #include <stddef.h> #include <stdint.h> ptrdiff_t half_max_capacity = PTRDIFF_MAX; $ clang++-mp-9.0 -pedantic -std=c++98 /tmp/test.cc -c /tmp/test.cc:4:31: warning: 'long long' is a C++11 extension [-Wc++11-long-long] ptrdiff_t half_max_capacity = PTRDIFF_MAX; ^ /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/stdint.h:149:23: note: expanded from macro 'PTRDIFF_MAX' #define PTRDIFF_MAX INT64_MAX ^ /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/stdint.h:75:26: note: expanded from macro 'INT64_MAX' #define INT64_MAX 9223372036854775807LL ^ 1 warning generated. * data/skeletons/glr.cc: here.	2019-12-08 16:34:53 +01:00
Akim Demaille	80f3220fea	api.token.raw: fix it in C++ Another breakage revealed by vcsn. * data/skeletons/c++.m4 (yytranslate_): Do not hard code "yy" and "parser", both can be changed by the user. Actually, since we are in the parser itself, there's really no need to qualify the type.	2019-12-08 16:07:50 +01:00
Akim Demaille	fc2040a750	c++: fix comments for %code blocks In a project of mine, vcsn, this commit fixes the following comments. --- /tmp/parse.hh 2019-12-08 15:51:24.792934703 +0100 +++ lib/vcsn/rat/parse.hh 2019-12-08 16:00:59.137107503 +0100 @@ -43,7 +43,7 @@ #ifndef YY_YY_USERS_AKIM_SRC_LRDE_2_LIB_VCSN_RAT_PARSE_HH_INCLUDED # define YY_YY_USERS_AKIM_SRC_LRDE_2_LIB_VCSN_RAT_PARSE_HH_INCLUDED -// // "%code requires" blocks. +// "%code requires" blocks. #line 20 "/Users/akim/src/lrde/2/lib/vcsn/rat/parse.yy" #include <iostream> @@ -1851,7 +1851,7 @@ -// // "%code provides" blocks. +// "%code provides" blocks. #line 60 "/Users/akim/src/lrde/2/lib/vcsn/rat/parse.yy" #define YY_DECL_(Class) \ * data/skeletons/bison.m4 (b4_percent_code_get): Pass an expanded string to b4_comment.	2019-12-08 16:03:36 +01:00
Akim Demaille	d55f240991	parser: pretend we are Bison 3.5 * src/parse-gram.y: Accept we're Bison 3.5.	2019-12-08 16:03:36 +01:00
Akim Demaille	4f961a706d	c++: fix spello * data/skeletons/lalr1.cc: here.	2019-12-08 15:42:41 +01:00
Akim Demaille	ac203e6c3c	todo: update * TODO: Schedule some features for 3.6. Remove obsolete stuff.	2019-12-08 10:12:02 +01:00
Akim Demaille	9141f0b79f	maint: post-release administrivia * NEWS: Add header line for next release. * .prev-version: Record previous version. * cfg.mk (old_NEWS_hash): Auto-update.	2019-12-08 09:29:24 +01:00
Akim Demaille	d57eab87e8	version 3.4.92 * NEWS: Record release date.	2019-12-08 09:12:30 +01:00
Akim Demaille	bb901beb68	news: fixes Reported by Paul Eggert. https://lists.gnu.org/archive/html/bison-patches/2019-12/msg00014.html * NEWS: here.	2019-12-08 09:12:07 +01:00
Akim Demaille	fa00c56c17	doc: minor changes * README-hacking.md: here.	2019-12-07 18:23:08 +01:00
Akim Demaille	5359c479bc	gnulib: update	2019-12-07 15:29:43 +01:00
Akim Demaille	20107b77c0	doc: clearly deprecate YYPRINT * doc/bison.texi (Prologue): Stop using YYPRINT as an example. (The YYPRINT Macro): Clearly show this macro is deprecated.	2019-12-07 15:29:43 +01:00
Akim Demaille	5e71eef267	doc: formatting changes * doc/bison.texi: here. No change in content.	2019-12-07 15:29:43 +01:00
Akim Demaille	472531dc72	news: update	2019-12-07 15:29:43 +01:00
Akim Demaille	046f238826	d: obey parse.error * data/skeletons/lalr1.d (yysyntax_error): Let the dispatch be bison-time, not runtime.	2019-12-07 13:23:45 +01:00
Akim Demaille	9bf06f6963	c++: also prefer YY_ASSERT to YYASSERT Like the other skeletons. * data/skeletons/variant.hh: here.	2019-12-07 13:23:45 +01:00
Akim Demaille	357336d254	glr.c: obey the parse.assert %define variable * data/skeletons/glr.c (YYASSERT): Rename as... (YY_ASSERT): this, for consistency with yacc.c, and also to emphasize the fact that this is not for the end user (YY_ prefix). * tests/glr-regression.at: Define parse.assert.	2019-12-07 13:23:45 +01:00
Akim Demaille	d4a6c3c58a	c++: beware of short ranges for state numbers Now that we use small integral types, possibly unsigned (e.g., unsigned char), to store state numbers, using -1 to denote an empty state (i.e., a state that stores no semantical value) is very dangerous: it will be confused with state 255, which might be non-empty. Rather than allocating a larger range of state numbers to keep the empty-state apart, let's use the number of a state known to store no value. The initial state, numbered 0, seems to fit perfectly the job. Reported by Frank Heckenbach. https://lists.gnu.org/archive/html/bug-bison/2019-11/msg00016.html * data/skeletons/lalr1.cc (empty_state): Be 0.	2019-12-07 09:22:55 +01:00
Akim Demaille	8976e0f567	api.token.raw: check it against api.token.constructor * tests/scanner.at: here.	2019-12-07 08:57:14 +01:00
Akim Demaille	6dca1eb950	regen	2019-12-06 08:27:55 +01:00
Akim Demaille	f8d82ff039	warnings: enable -Wuseless-cast, and eliminate warnings Prompted by Frank Heckenbach. https://lists.gnu.org/archive/html/bug-bison/2019-11/msg00016.html. * configure.ac (warn_cxx): Add -Wuseless-cast. * data/skeletons/c.m4 (b4_attribute_define): Define YY_IGNORE_USELESS_CAST_BEGIN and YY_IGNORE_USELESS_CAST_END. * data/skeletons/glr.c (YY_FPRINTF): New, replaces YYFPRINTF, wrapped with YY_IGNORE_USELESS_CAST_BEGIN and YY_IGNORE_USELESS_CAST_END. (YY_DPRINTF): Likewise. * tests/actions.at: Remove useless cast. * tests/headers.at: Adjust.	2019-12-06 08:27:55 +01:00
Akim Demaille	9e9e49224f	diagnostics: style changes * src/complain.h, src/complain.c: Comment changes. * src/scan-skel.l: Reduce scopes. * data/skeletons/bison.m4: Factor diagnostic functions.	2019-12-02 19:35:01 +01:00
Akim Demaille	8b53f4e022	glr.c: style changes * data/skeletons/glr.c (yysplitStack): Reduce scopes. * tests/atlocal.in: Formatting changes.	2019-12-02 19:34:48 +01:00
Akim Demaille	8c87a62308	c++: get rid of symbol_type::token () It is not used. And its implementation was wrong when api.token.raw was defined, as it was still mapping to the external token numbers, instead of the internal ones. Besides it was provided only when api.token.constructor is defined, yet always declared. * data/skeletons/c++.m4 (by_type::token): Remove, useless.	2019-12-01 10:05:48 +01:00
Akim Demaille	478cb5cf12	c++: remove useless cast about user_token_number_max_ Reported by Frank Heckenbach. https://lists.gnu.org/archive/html/bug-bison/2019-11/msg00016.html The cast is needed when yytranslate_'s argument type is token_type, i.e., when api.token.constructor is defined. 373. types.at:138: testing lalr1.cc api.value.type=variant api.token.constructor ... ======== Testing with C++ standard flags: '' ../../tests/types.at:138: bison --color=no -fno-caret -o test.cc test.y ../../tests/types.at:138: $CXX $CXXFLAGS $CPPFLAGS $LDFLAGS -o test test.cc $LIBS stderr: test.cc:966:16: error: result of comparison of constant 257 with expression of type 'yy::parser::token_type' (aka 'yy::parser::token::yytokentype') is always true [-Werror,-Wtautological-constant-out-of-range-compare] else if (t <= user_token_number_max_) ~ ^ ~~~~~~~~~~~~~~~~~~~~~~ 1 error generated. It is because it is expected that when api.token.constructor is defined, only symbol constructors will be used, that yytranslate_ then takes a token_type. But it is wrong: we still allow literal characters in this case, as demonstrated by test 373 for instance. %define api.value.type variant %define api.token.constructor %token <std::pair<int, int>> '1' '2'; [...] static yy::parser::symbol_type yylex () { static char const input[] = "12"; int res = input[toknum++]; typedef yy::parser::symbol_type symbol; if (res) return symbol (res, std::make_pair (res - '0', res - '0' + 1)); else return symbol (res); } So let yytranslate_ always take an int, which makes the cast truly useless. * data/skeletons/c++.m4, data/skeletons/lalr1.cc (yytranslate_): here.	2019-12-01 08:53:58 +01:00
Akim Demaille	94f70bd861	c++: clean a few issues wrt special tokens The C++ implementation of LAC did not skip the $undefined token, probably because it was not exposed. Expose it, and use clearer names. * data/skeletons/c++.m4: Don't define undef_token_ in yytranslate_, but... * data/skeletons/lalr1.cc (yy_undef_token_): here. Use a more precise type to define yy_undef_token_ and yy_error_token_. Unfortunately we move from a compile-time value defined via an enum to a static const member. Eventually we should make it constexpr. Make LAC implementation more alike yacc.c's one.	2019-12-01 08:08:19 +01:00
Akim Demaille	9b4f0970fe	d, java: improve yytranslate and neighbors * data/skeletons/lalr1.d, data/skeletons/lalr1.java: Don't expose yyuser_token_number_max_ and yyundef_token_. Do as in C++: scope them into yytranslate_, and only when api.token.raw is not defined. (yyterror_): Rename as... (yy_error_token_): this. * data/skeletons/lalr1.d (token_number_type): New. Use it. Can't be done in the Java backend, as Java does not have type aliases.	2019-12-01 07:59:23 +01:00
Akim Demaille	869028a66d	d, java: get rid of a useless table * data/skeletons/lalr1.d, data/skeletons/lalr1.java (yytoken_number_): Remove, useless. Was used in ancient C skeletons to support YYPRINT, long obsoleted by %printer.	2019-12-01 07:38:31 +01:00
Akim Demaille	6f92a7f664	c++, d, java: remove yyerrcode It is not used at all. We will remove it also from yacc.c, but later (see TODO). * data/skeletons/lalr1.cc, data/skeletons/lalr1.d, * data/skeletons/lalr1.java (yyerrcode_): Remove.	2019-11-30 17:30:48 +01:00
Akim Demaille	6a61b6b17e	c++: improve typing * data/skeletons/lalr1.cc (yysyntax_error_): symbol_type::type_get returns a symbol_number_type (which is indeed an int).	2019-11-30 17:30:48 +01:00
Akim Demaille	a4bf7cdf9e	c++: remove useless cast about yyeof_ Reported by Frank Heckenbach. https://lists.gnu.org/archive/html/bug-bison/2019-11/msg00016.html * data/skeletons/c++.m4 (b4_yytranslate_define): Don't use yyeof_ as if it had two different types. It is used once against the input argument, which is the value returned by yylex, which is an "external token number", typically an int. It is also used as output type, an "internal symbol number". It turns out that in both cases we mean "0", but let's keep yyeof_ only for the case "internal symbol number", i.e., _after_ conversion by yytranslate. This frees us from one cast.	2019-11-30 17:30:48 +01:00
Akim Demaille	9471a5ffe9	glr: style change * data/skeletons/glr.c (YYDPRINTF): Expand into an empty statement, instead of nothing. Simplify callers.	2019-11-30 14:41:16 +01:00
Akim Demaille	24c5214ae8	glr: remove useless casts Reported by GCC's -Wuseless-cast. * data/skeletons/glr.c: Don't cast to yybool, it's useless.	2019-11-30 14:41:16 +01:00
Akim Demaille	2f7097d1b1	yacc.c, glr.c: fix crash when reporting errors in consistent states The current code for yysyntax_error for %define parse.error verbose is fishy (given that YYEMPTY is -2, invalid argument for yytname[]): static int yysyntax_error ([...]) { YYPTRDIFF_T yysize0 = yytnamerr (YY_NULLPTR, yytname[yytoken]); [...] if (yytoken != YYEMPTY) A nearby comment reports The only way there can be no lookahead present (in yychar) is if this state is a consistent state with a default action. Thus, detecting the absence of a lookahead is sufficient to determine that there is no unexpected or expected token to report. In that case, just report a simple "syntax error". So it _is_ possible to call yysyntax_error with yytoken == YYEMPTY, albeit quite difficult when meaning to, so virtually impossible by accident (after all, there was never a bug report about this). I failed to produce a test case, but Joel E. Denny provided me with one (added to the test suite below). The yacc.c skeleton fails on this, and once fixed dies on a second problem. The glr.c skeleton was also dying, but immediately of this second problem. Indeed we were not allocating space for the error message's final \0. This was hidden by the fact that we only had error messages with at least an unexpected token displayed, so with at least one "%s" in the format string, whose size (2) was included (incorrectly) in the final size of the message (where the %s have been replaced by the actual content). * data/skeletons/glr.c, data/skeletons/yacc.c (yysyntax_error): Do not invoke yytnamerr on YYEMPTY. Clarify the computation of the length of the _final_ error message, with the NUL terminator but without the '%s's. * tests/conflicts.at (Syntax error in consistent error state): New, contributed by Joel E. Denny.	2019-11-29 18:21:43 +01:00
Akim Demaille	28369ecb5d	tests: avoid creating files whose name collide with standard headers Having a file named "exception" is risky: the compiler might use that file in #include. Reported by 马俊 <[email protected]>. * tests/local.at (AT_SKIP_IF_EXCEPTION_SUPPORT_IS_POOR): Generate 'exceptions', not 'exception'.	2019-11-26 08:05:32 +01:00
Akim Demaille	b92f064e9b	doc: more details about the test suite * README-hacking.md: here.	2019-11-22 09:02:06 +01:00
Akim Demaille	98f19578aa	maint: post-release administrivia * NEWS: Add header line for next release. * .prev-version: Record previous version. * cfg.mk (old_NEWS_hash): Auto-update.	2019-11-20 07:49:44 +01:00
@@ -1 +1 @@
 .4.90
 .4.92