maint: credit Wojciech Polak

[bison.git] / data / lalr1.cc

diff --git a/data/lalr1.cc b/data/lalr1.cc
index 2ec1d0d702f6277d8885809279472c520bd037f5..237b246f5be6490e7393028c86f425d1b57fc4c5 100644 (file)
--- a/data/lalr1.cc
+++ b/data/lalr1.cc
@@ -24,17 +24,14 @@ m4_define([b4_parser_class_name],
 b4_defines_if([],
               [b4_fatal([b4_skeleton[: using %%defines is mandatory]])])
 
-b4_percent_define_ifdef([[location_type]], [],
+b4_percent_define_ifdef([[api.location.type]], [],
   [# Backward compatibility.
   m4_define([b4_location_constructors])
   m4_include(b4_pkgdatadir/[location.cc])])
 m4_include(b4_pkgdatadir/[stack.hh])
 
-# We do want M4 expansion after # for CPP macros.
-m4_changecom()
-m4_divert_push(0)dnl
 b4_defines_if(
-[@output(b4_spec_defines_file@)@
+[b4_output_begin([b4_spec_defines_file])
 b4_copyright([Skeleton interface for Bison LALR(1) parsers in C++],
              [2002-2012])
 [
@@ -52,7 +49,7 @@ b4_copyright([Skeleton interface for Bison LALR(1) parsers in C++],
 #include <string>
 #include <iostream>
 #include "stack.hh"
-]b4_percent_define_ifdef([[location_type]], [],
+]b4_percent_define_ifdef([[api.location.type]], [],
                          [[#include "location.hh"]])[
 
 ]b4_YYDEBUG_define[
@@ -77,7 +74,7 @@ b4_user_stype
     typedef ]b4_api_PREFIX[STYPE semantic_type;
 #endif
     /// Symbol locations.
-    typedef ]b4_percent_define_get([[location_type]],
+    typedef ]b4_percent_define_get([[api.location.type]],
                                    [[location]])[ location_type;
     /// Tokens.
     struct token
@@ -227,6 +224,7 @@ b4_user_stype
 
     /// \brief Reclaim the memory associated to a symbol.
     /// \param yymsg        Why this token is reclaimed.
+    ///                     If null, do not display the symbol, just free it.
     /// \param yytype       The symbol type.
     /// \param yyvaluep     Its semantic value.
     /// \param yylocationp  Its location.
@@ -264,8 +262,11 @@ b4_user_stype
 ])[
 ]b4_percent_code_get([[provides]])[
 ]b4_cpp_guard_close([b4_spec_defines_file])
-])dnl
-@output(b4_parser_file_name@)@
+b4_output_end()
+])
+
+
+b4_output_begin([b4_parser_file_name])
 b4_copyright([Skeleton implementation for Bison LALR(1) parsers in C++],
              [2002-2012])
 b4_percent_code_get([[top]])[]dnl
@@ -446,7 +447,8 @@ do {                                        \
     YYUSE (yymsg);
     YYUSE (yyvaluep);
 
-    YY_SYMBOL_PRINT (yymsg, yytype, yyvaluep, yylocationp);
+    if (yymsg)
+      YY_SYMBOL_PRINT (yymsg, yytype, yyvaluep, yylocationp);
 
     switch (yytype)
       {
@@ -510,17 +512,18 @@ do {                                      \
     int yychar = yyempty_;
     int yytoken = 0;
 
-    /* State.  */
+    // State.
     int yyn;
     int yylen = 0;
     int yystate = 0;
 
-    /* Error handling.  */
+    // Error handling.
     int yynerrs_ = 0;
     int yyerrstatus_ = 0;
 
     /// Semantic value of the lookahead.
-    semantic_type yylval;
+    static semantic_type yyval_default;
+    semantic_type yylval = yyval_default;
     /// Location of the lookahead.
     location_type yylloc;
     /// The locations where the error started and ended.
@@ -841,20 +844,22 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
     }
     catch (...)
       {
-        YYCDEBUG << "Exception caught" << std::endl;
+        YYCDEBUG << "Exception caught: cleaning lookahead and stack"
+                 << std::endl;
+        // Do not try to display the values of the reclaimed symbols,
+        // as their printer might throw an exception.
         if (yychar != yyempty_)
           {
             /* Make sure we have latest lookahead translation.  See
                comments at user semantic actions for why this is
                necessary.  */
             yytoken = yytranslate_ (yychar);
-            yydestruct_ ("Cleanup: discarding lookahead", yytoken, &yylval,
-                         &yylloc);
+            yydestruct_ (YY_NULL, yytoken, &yylval, &yylloc);
           }
 
         while (1 < yystate_stack_.height ())
           {
-            yydestruct_ ("Cleanup: popping",
+            yydestruct_ (YY_NULL,
                          yystos_[yystate_stack_[0]],
                          &yysemantic_stack_[0],
                          &yylocation_stack_[0]);
@@ -1135,4 +1140,4 @@ b4_error_verbose_if([int yystate, int yytoken],
 
 ]b4_namespace_close[
 ]b4_epilogue[]dnl
-m4_divert_pop(0)
+b4_output_end()