glr2.cc: fork glr.cc to a c++ version

This is a fork of glr.cc to be c++-first instead of a wrapper around
glr.c.

* data/skeletons/glr2.cc: New.
* data/skeletons/bison.m4, data/skeletons/c++.m4: Adjust.
* data/skeletons/c.m4 (b4_user_args_no_comma): New.
* src/reader.c (grammar_rule_check_and_complete): glr2.cc is C++.
* tests/actions.at, tests/c++.at, tests/calc.at, tests/conflicts.at,
* tests/input.at, tests/local.at, tests/regression.at, tests/scanner.at,
* tests/synclines.at, tests/types.at: Also check glr2.cc.

NEWS

@@ -6,6 +6,19 @@ GNU Bison NEWS
 
   Push parsers use YYMALLOC/YYFREE instead of direct calls to malloc/free.
 
+** Changes
+
+  A new version of the generated C++ GLR parser was added as "glr2.cc". It
+  is forked from the existing glr.c/cc parser, with the objective of making
+  it a more modern, truly C++ parser (instead of a C++ wrapper around a C
+  parser).  Down the line, the goal is to support `%define api.value.type
+  variant` and maybe share code with lalr1.cc.
+
+  The current parser should be identical in terms of interface, functionality
+  and performance to "glr.cc". To try it out, simply use
+
+  %skeleton "glr2.cc"
+
 * Noteworthy changes in release 3.7.1 (2020-08-02) [stable]
 
 ** Bug fixes

data/local.mk

@@ -28,6 +28,7 @@ dist_skeletons_DATA =                           \
   data/skeletons/c.m4                           \
   data/skeletons/glr.c                          \
   data/skeletons/glr.cc                         \
+  data/skeletons/glr2.cc                        \
   data/skeletons/java-skel.m4                   \
   data/skeletons/java.m4                        \
   data/skeletons/lalr1.cc                       \

data/skeletons/bison.m4

@@ -402,7 +402,7 @@ b4_define_flag_if([yacc])               # Whether POSIX Yacc is emulated.
 # b4_glr_cc_if([IF-TRUE], [IF-FALSE])
 # -----------------------------------
 m4_define([b4_glr_cc_if],
-          [m4_if(b4_skeleton, ["glr.cc"], $@)])
+          [m4_if(m4_bregexp(b4_skeleton, [^"glr2?.cc"$]), [0], $@)])
 
 
 ## --------- ##

data/skeletons/c++.m4

@@ -109,7 +109,6 @@ b4_percent_define_default([[api.filename.type]], [[const std::string]])
 # Make it a warning for those who used betas of Bison 3.0.
 b4_percent_define_default([[api.namespace]], m4_defn([b4_prefix]))
 
-b4_percent_define_default([[global_tokens_and_yystype]], [[false]])
 b4_percent_define_default([[define_location_comparison]],
                           [m4_if(b4_percent_define_get([[filename_type]]),
                                  [std::string], [[true]], [[false]])])

data/skeletons/c.m4

@@ -127,7 +127,12 @@ m4_define([b4_lex],
 # b4_user_args
 # ------------
 m4_define([b4_user_args],
-[m4_ifset([b4_parse_param], [, b4_args(b4_parse_param)])])
+[m4_ifset([b4_parse_param], [, b4_user_args_no_comma])])
+
+# b4_user_args_no_comma
+# ------------
+m4_define([b4_user_args_no_comma],
+[m4_ifset([b4_parse_param], [b4_args(b4_parse_param)])])
 
 
 # b4_user_formals

src/reader.c

@@ -297,6 +297,7 @@ grammar_rule_check_and_complete (symbol_list *r)
               const bool is_cxx =
                 STREQ (language->language, "c++")
                 || (skeleton && (STREQ (skeleton, "glr.cc")
+                                 || STREQ (skeleton, "glr2.cc")
                                  || STREQ (skeleton, "lalr1.cc")));
               if (is_cxx)
                 {

tests/actions.at

@@ -371,6 +371,7 @@ AT_TEST([glr.c])
 AT_TEST([glr.c], [%define api.pure])
 AT_TEST([lalr1.cc])
 AT_TEST([glr.cc])
+AT_TEST([glr2.cc])
 
 ## A very different test, based on PostgreSQL's implementation of the
 ## locations.  See
@@ -474,7 +475,7 @@ AT_CLEANUP
 ])
 
 ## FIXME: test Java and D.
-m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc])
+m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc], [glr2.cc])
 
 m4_popdef([AT_TEST])
 
@@ -1055,6 +1056,9 @@ AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "lalr1.cc"], [ with union])
 AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "glr.cc"])
 AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "glr.cc"], [ with union])
 
+AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "glr2.cc"])
+AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "glr2.cc"], [ with union])
+
 
 
 ## ----------------------------------------- ##
@@ -1852,7 +1856,7 @@ AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 ])
 
-m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc])
+m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc], [glr2.cc])
 m4_popdef([AT_TEST])
 
 ## -------------------------------------------------- ##

tests/c++.at

@@ -1062,6 +1062,7 @@ AT_CLEANUP
 
 AT_TEST([%skeleton "lalr1.cc"])
 AT_TEST([%skeleton "glr.cc"])
+AT_TEST([%skeleton "glr2.cc"])
 
 m4_popdef([AT_TEST])
 

tests/calc.at

@@ -1204,6 +1204,7 @@ AT_BANNER([[GLR C++ Calculator.]])
 
 # Again, we try also using %skeleton.
 AT_CHECK_CALC([%skeleton "glr.cc"])
+AT_CHECK_CALC([%skeleton "glr2.cc"])
 
 m4_define([AT_CHECK_CALC_GLR_CC],
 [AT_CHECK_CALC([%language "C++" %glr-parser] $@)])

tests/conflicts.at

@@ -1093,7 +1093,7 @@ AT_CLEANUP
 ])
 
 ## FIXME: test Java and D.
-m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc])
+m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc], [glr2.cc])
 
 m4_popdef([AT_TEST])
 

tests/input.at

@@ -2865,6 +2865,7 @@ AT_BISON_CHECK([[-d               input.y]])
 AT_BISON_CHECK([[-d -S glr.c      input.y]])
 AT_BISON_CHECK([[-d -S lalr1.cc   input.y]])
 AT_BISON_CHECK([[-d -S glr.cc     input.y]])
+AT_BISON_CHECK([[-d -S glr2.cc    input.y]])
 AT_BISON_CHECK([[   -S lalr1.java input.y]])
 ])
 

tests/local.at

@@ -237,7 +237,7 @@ m4_pushdef([AT_LANG],
 m4_pushdef([AT_C_IF],
 [m4_if(AT_LANG, [c], [$1], [$2])])
 m4_pushdef([AT_GLR_IF],
-[m4_bmatch([$3], [%glr-parser\|%skeleton "glr\..*"], [$1], [$2])])
+[m4_bmatch([$3], [%glr-parser\|%skeleton "glr.*"], [$1], [$2])])
 m4_pushdef([AT_LALR1_CC_IF],
 [AT_CXX_IF([AT_GLR_IF([$2], [$1])], [$2])])
 m4_pushdef([AT_GLR_CC_IF],

tests/regression.at

@@ -1557,6 +1557,7 @@ AT_TEST([yacc.c])
 AT_TEST([glr.c])
 AT_TEST([lalr1.cc])
 AT_TEST([glr.cc])
+AT_TEST([glr2.cc])
 
 m4_popdef([AT_TEST])
 

tests/scanner.at

@@ -333,7 +333,7 @@ AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 ])
 
-m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], [glr.cc], [lalr1.java], [lalr1.d]],
+m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], [glr.cc], [glr2.cc], [lalr1.java], [lalr1.d]],
 [AT_TEST([%skeleton "]b4_skel["])
  AT_TEST([%skeleton "]b4_skel[" %define api.token.raw])])
 

tests/synclines.at

@@ -437,7 +437,7 @@ AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 ])
 
-m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc])
+m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc], [glr2.cc])
 
 m4_popdef([AT_TEST])
 
@@ -494,7 +494,7 @@ AT_BISON_OPTION_POPDEFS
 AT_CLEANUP
 ])
 
-m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc])
+m4_map_args([AT_TEST], [yacc.c], [glr.c], [lalr1.cc], [glr.cc], [glr2.cc])
 
 m4_popdef([AT_TEST])
 

tests/types.at

@@ -135,7 +135,7 @@ m4_pushdef([AT_TEST],
  _AT_TEST([$1 %defines], [$2], [$3], [$4], [$5], [$6], [$7])
 ])
 
-m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], [glr.cc]],
+m4_foreach([b4_skel], [[yacc.c], [glr.c], [lalr1.cc], [glr.cc], [glr2.cc]],
  [# A built-in type.
   AT_TEST([%skeleton "]b4_skel["
            %define api.value.type {double}],