]> git.saurik.com Git - bison.git/blobdiff - data/lalr1.cc
gnulib: update
[bison.git] / data / lalr1.cc
index dab5ab9b05be425e69739d52ff984fd51f13d50b..7b2aef2d85f82b6150f77dd490bd42047c4e9e36 100644 (file)
@@ -1,6 +1,6 @@
 # C++ skeleton for Bison
 
-# Copyright (C) 2002-2011 Free Software Foundation, Inc.
+# Copyright (C) 2002-2012 Free Software Foundation, Inc.
 
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -22,7 +22,7 @@ m4_include(b4_pkgdatadir/[c++.m4])
 # --------------------------------------------------------------
 # Declare "parser::yy<TABLE-NAME>_" which contents is CONTENT.
 m4_define([b4_integral_parser_table_declare],
-[m4_ifval([$3], [b4_c_comment([$3], [  ])
+[m4_ifval([$3], [b4_comment([$3], [  ])
 ])dnl
   static const b4_int_type_for([$2]) yy$1_[[]];dnl
 ])
@@ -98,84 +98,58 @@ m4_define([b4_rhs_location],
 # Same as in C, but using references instead of pointers.
 m4_define([b4_symbol_action],
 [b4_symbol_if([$1], [has_$2],
-[m4_pushdef([b4_dollar_dollar],
-    [b4_symbol_value_template([yysym.value],
-                              b4_symbol_if([$1], [has_type],
-                                           [b4_symbol([$1], [type])]))])dnl
-m4_pushdef([b4_at_dollar], [yysym.location])dnl
+[m4_pushdef([b4_symbol_value], m4_defn([b4_symbol_value_template]))[]dnl
+b4_dollar_pushdef([yysym.value],
+                   b4_symbol_if([$1], [has_type],
+                                [m4_dquote(b4_symbol([$1], [type]))]),
+                   [yysym.location])dnl
       b4_symbol_case_([$1])
 b4_syncline([b4_symbol([$1], [$2_line])], ["b4_symbol([$1], [$2_file])"])
         b4_symbol([$1], [$2])
 b4_syncline([@oline@], [@ofile@])
         break;
 
-m4_popdef([b4_at_dollar])dnl
-m4_popdef([b4_dollar_dollar])dnl
+m4_popdef([b4_symbol_value])[]dnl
+b4_dollar_popdef[]dnl
 ])])
 
 
 m4_pushdef([b4_copyright_years],
-           [2002-2011])
+           [2002-2012])
 
 m4_define([b4_parser_class_name],
           [b4_percent_define_get([[parser_class_name]])])
 
-# The header is mandatory.
-b4_defines_if([],
-              [b4_fatal([b4_skeleton[: using %%defines is mandatory]])])
-
-b4_locations_if([b4_percent_define_ifdef([[location_type]], [],
-  [# Backward compatibility.
-  m4_define([b4_location_constructors])
-  m4_include(b4_pkgdatadir/[location.cc])])])
+b4_bison_locations_if([# Backward compatibility.
+   m4_define([b4_location_constructors])
+   m4_include(b4_pkgdatadir/[location.cc])])
 m4_include(b4_pkgdatadir/[stack.hh])
 b4_variant_if([m4_include(b4_pkgdatadir/[variant.hh])])
 
-# We do want M4 expansion after # for CPP macros.
-m4_changecom()
-m4_divert_push(0)dnl
-@output(b4_spec_defines_file@)@
-b4_copyright([Skeleton interface for Bison LALR(1) parsers in C++])
-dnl FIXME: This is wrong, we want computed header guards.
-[
-/* C++ LALR(1) parser skeleton written by Akim Demaille.  */
-
-#ifndef PARSER_HEADER_H
-# define PARSER_HEADER_H
-
-]b4_percent_code_get([[requires]])[
-
-]b4_parse_assert_if([#include <cassert>])[
-#include <stdexcept>
-#include <string>
-#include <iostream>
-#include "stack.hh"
-]b4_locations_if([b4_percent_define_ifdef([[location_type]], [],
-                                          [[#include "location.hh"]])])[
-
-]b4_variant_if([b4_namespace_open
-b4_variant_define
-b4_namespace_close])[
+# b4_shared_declarations
+# ----------------------
+# Declaration that might either go into the header (if --defines)
+# or open coded in the parser body.
+m4_define([b4_shared_declarations],
+[b4_percent_code_get([[requires]])[
+]b4_parse_assert_if([# include <cassert>])[
+# include <deque>
+# include <iostream>
+# include <stdexcept>
+# include <string>]b4_defines_if([[
+# include "stack.hh"
+]b4_bison_locations_if([[# include "location.hh"]])])[
+
+]b4_YYDEBUG_define[
 
-/* Enabling traces.  */
-#ifndef YYDEBUG
-# define YYDEBUG ]b4_parse_trace_if([1], [0])[
-#endif
-
-/* Enabling verbose error messages.  */
-#ifdef YYERROR_VERBOSE
-# undef YYERROR_VERBOSE
-# define YYERROR_VERBOSE 1
-#else
-# define YYERROR_VERBOSE ]b4_error_verbose_if([1], [0])[
-#endif
+]b4_namespace_open[
 
-/* Enabling the token table.  */
-#ifndef YYTOKEN_TABLE
-# define YYTOKEN_TABLE ]b4_token_table[
-#endif
+]b4_defines_if([],
+[b4_stack_define
+b4_bison_locations_if([b4_position_define
+b4_location_define])])[
 
-]b4_namespace_open[
+]b4_variant_if([b4_variant_define])[
 
   /// A Bison parser.
   class ]b4_parser_class_name[
@@ -190,7 +164,7 @@ b4_namespace_close])[
     /// \returns  0 iff parsing succeeded.
     virtual int parse ();
 
-#if YYDEBUG
+#if ]b4_api_PREFIX[DEBUG
     /// The current debugging stream.
     std::ostream& debug_stream () const;
     /// Set the current debugging stream.
@@ -204,10 +178,13 @@ b4_namespace_close])[
     void set_debug_level (debug_level_type l);
 #endif
 
-    /// Report a syntax error.]b4_locations_if([
-    /// \param loc    where the syntax error is found.])[
+    /// Report a syntax error.]b4_locations_if([[
+    /// \param loc    where the syntax error is found.]])[
     /// \param msg    a description of the syntax error.
-    virtual void error (]b4_locations_if([const location_type& loc, ])[const std::string& msg);
+    virtual void error (]b4_locations_if([[const location_type& loc, ]])[const std::string& msg);
+
+    /// Report a syntax error.
+    void error (const syntax_error& err);
 
   private:
     /// State numbers.
@@ -236,18 +213,16 @@ b4_namespace_close])[
     static const ]b4_int_type(b4_pact_ninf, b4_pact_ninf)[ yypact_ninf_;
     static const ]b4_int_type(b4_table_ninf, b4_table_ninf)[ yytable_ninf_;
 
-    /* Tables.  */
-]b4_parser_tables_declare[
-
-#if YYDEBUG || YYERROR_VERBOSE || YYTOKEN_TABLE
-    /// For a symbol, its name in clear.
-    static const char* const yytname_[];
-#endif]b4_error_verbose_if([
+    // Tables.
+]b4_parser_tables_declare[]b4_error_verbose_if([
 
     /// Convert the symbol name \a n to a form suitable for a diagnostic.
     static std::string yytnamerr_ (const char *n);])[
 
-#if YYDEBUG
+]b4_token_table_if([], [[#if ]b4_api_PREFIX[DEBUG]])[
+    /// For a symbol, its name in clear.
+    static const char* const yytname_[];
+]b4_token_table_if([[#if ]b4_api_PREFIX[DEBUG]])[
 ]b4_integral_parser_table_declare([rline], [b4_rline],
      [YYRLINE[YYN] -- Source line where rule number YYN was defined.])[
     /// Report on the debug stream that the rule \a r is going to be reduced.
@@ -255,15 +230,15 @@ b4_namespace_close])[
     /// Print the state stack on the debug stream.
     virtual void yystack_print_ ();
 
-    /* Debugging.  */
+    // Debugging.
     int yydebug_;
     std::ostream* yycdebug_;
-#endif
+#endif // ]b4_api_PREFIX[DEBUG
 
     /// Convert a scanner token number \a t to a symbol number.
-    static inline token_number_type yytranslate_ (]b4_lex_symbol_if([token_type], [int])[ t);
+    static inline token_number_type yytranslate_ (]b4_token_ctor_if([token_type], [int])[ t);
 
-#if YYDEBUG
+#if ]b4_api_PREFIX[DEBUG
     /// \brief Display a symbol type, value and location.
     /// \param yyo    The output stream.
     /// \param yysym  The symbol.
@@ -291,7 +266,7 @@ b4_namespace_close])[
       inline stack_symbol_type ();
 
       /// Constructor.
-      inline stack_symbol_type (]b4_args([state_type s],
+      inline stack_symbol_type (]b4_join([state_type s],
                                          [const semantic_type& v],
                                          b4_locations_if([const location_type& l]))[);
 
@@ -336,28 +311,46 @@ b4_namespace_close])[
       yyfinal_ = ]b4_final_state_number[, //< Termination state number.
       yyterror_ = 1,
       yyerrcode_ = 256,
-      yyntokens_ = ]b4_tokens_number[,   //< Number of tokens.
+      yyntokens_ = ]b4_tokens_number[    //< Number of tokens.
     };
 
 ]b4_parse_param_vars[
   };
 
-]b4_lex_symbol_if([b4_yytranslate_define
+]b4_token_ctor_if([b4_yytranslate_define
 b4_public_types_define])[
 ]b4_namespace_close[
 
 ]b4_percent_define_flag_if([[global_tokens_and_yystype]],
-[b4_token_defines(b4_tokens)
+[b4_token_defines
 
-#ifndef YYSTYPE
+#ifndef ]b4_api_PREFIX[STYPE
  /* Redirection for backward compatibility.  */
-# define YYSTYPE b4_namespace_ref::b4_parser_class_name::semantic_type
+# define ]b4_api_PREFIX[STYPE b4_namespace_ref::b4_parser_class_name::semantic_type
 #endif
+])[
+]b4_percent_code_get([[provides]])[
+]])
+
+b4_defines_if(
+[b4_output_begin([b4_spec_defines_file])
+b4_copyright([Skeleton interface for Bison LALR(1) parsers in C++])
+[
+/**
+ ** \file ]b4_spec_defines_file[
+ ** Define the ]b4_namespace_ref[::parser class.
+ */
+
+/* C++ LALR(1) parser skeleton written by Akim Demaille.  */
+
+]b4_cpp_guard_open([b4_spec_defines_file])[
+]b4_shared_declarations[
+]b4_cpp_guard_close([b4_spec_defines_file])
+b4_output_end()
 ])
-b4_percent_code_get([[provides]])[]dnl
 
-[#endif /* ! defined PARSER_HEADER_H */]
-@output(b4_parser_file_name@)@
+
+b4_output_begin([b4_parser_file_name])
 b4_copyright([Skeleton implementation for Bison LALR(1) parsers in C++])
 b4_percent_code_get([[top]])[]dnl
 m4_if(b4_prefix, [yy], [],
@@ -365,16 +358,19 @@ m4_if(b4_prefix, [yy], [],
 // Take the name prefix into account.
 #define yylex   b4_prefix[]lex])[
 
-/* First part of user declarations.  */
+// First part of user declarations.
 ]b4_user_pre_prologue[
 
-#include "@basename(]b4_spec_defines_file[@)"
+]b4_null_define[
+
+]b4_defines_if([[#include "@basename(]b4_spec_defines_file[@)"]],
+               [b4_shared_declarations])[
 
 /* User implementation prologue.  */
-]b4_user_post_prologue
-b4_percent_code_get[]dnl
+]b4_user_post_prologue[
+]b4_percent_code_get[
 
-[#ifndef YY_
+#ifndef YY_
 # if defined YYENABLE_NLS && YYENABLE_NLS
 #  if ENABLE_NLS
 #   include <libintl.h> /* FIXME: INFRINGES ON USER NAME SPACE */
@@ -387,31 +383,14 @@ b4_percent_code_get[]dnl
 #endif
 
 ]b4_locations_if([dnl
-[/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].
-   If N is 0, then set CURRENT to the empty location which ends
-   the previous symbol: RHS[0] (always defined).  */
-
-#define YYRHSLOC(Rhs, K) ((Rhs)[K].location)
-#ifndef YYLLOC_DEFAULT
-# define YYLLOC_DEFAULT(Current, Rhs, N)                               \
- do                                                                    \
-   if (N)                                                              \
-     {                                                                 \
-       (Current).begin = YYRHSLOC (Rhs, 1).begin;                      \
-       (Current).end   = YYRHSLOC (Rhs, N).end;                        \
-     }                                                                 \
-   else                                                                \
-     {                                                                 \
-       (Current).begin = (Current).end = YYRHSLOC (Rhs, 0).end;        \
-     }                                                                 \
- while (false)
-#endif]])[
+[#define YYRHSLOC(Rhs, K) ((Rhs)[K].location)
+]b4_yylloc_default_define])[
 
 /* Suppress unused-variable warnings by "using" E.  */
 #define YYUSE(e) ((void) (e))
 
 /* Enable debugging if requested.  */
-#if YYDEBUG
+#if ]b4_api_PREFIX[DEBUG
 
 /* A pseudo ostream that takes yydebug_ into account.  */
 # define YYCDEBUG if (yydebug_) (*yycdebug_)
@@ -426,26 +405,26 @@ b4_percent_code_get[]dnl
     }                                           \
   } while (false)
 
-# define YY_REDUCE_PRINT(Rule)         \
-  do {                                 \
+# define YY_REDUCE_PRINT(Rule)          \
+  do {                                  \
     if (yydebug_)                       \
-      yy_reduce_print_ (Rule);         \
+      yy_reduce_print_ (Rule);          \
   } while (false)
 
-# define YY_STACK_PRINT()              \
-  do {                                 \
+# define YY_STACK_PRINT()               \
+  do {                                  \
     if (yydebug_)                       \
       yystack_print_ ();                \
   } while (false)
 
-#else /* !YYDEBUG */
+#else /* !]b4_api_PREFIX[DEBUG */
 
 # define YYCDEBUG if (false) std::cerr
-# define YY_SYMBOL_PRINT(Title, Symbol)  static_cast<void>(0)
+# define YY_SYMBOL_PRINT(Title, Symbol)  YYUSE(Symbol)
 # define YY_REDUCE_PRINT(Rule)           static_cast<void>(0)
 # define YY_STACK_PRINT()                static_cast<void>(0)
 
-#endif /* !YYDEBUG */
+#endif /* !]b4_api_PREFIX[DEBUG */
 
 #define yyerrok         (yyerrstatus_ = 0)
 #define yyclearin       (yyempty = true)
@@ -498,7 +477,7 @@ b4_percent_code_get[]dnl
   /// Build a parser object.
   ]b4_parser_class_name::b4_parser_class_name[ (]b4_parse_param_decl[)]m4_ifset([b4_parse_param], [
     :])[
-#if YYDEBUG
+#if ]b4_api_PREFIX[DEBUG
     ]m4_ifset([b4_parse_param], [  ], [ :])[yydebug_ (false),
       yycdebug_ (&std::cerr)]m4_ifset([b4_parse_param], [,])[
 #endif]b4_parse_param_cons[
@@ -514,7 +493,7 @@ b4_percent_code_get[]dnl
   | Symbol types.  |
   `---------------*/
 
-]b4_lex_symbol_if([], [b4_public_types_define])[
+]b4_token_ctor_if([], [b4_public_types_define])[
 
   // stack_symbol_type.
   ]b4_parser_class_name[::stack_symbol_type::stack_symbol_type ()
@@ -523,7 +502,7 @@ b4_percent_code_get[]dnl
   {
   }
 
-  ]b4_parser_class_name[::stack_symbol_type::stack_symbol_type (]b4_args(
+  ]b4_parser_class_name[::stack_symbol_type::stack_symbol_type (]b4_join(
                  [state_type s],
                  [const semantic_type& v],
                  b4_locations_if([const location_type& l]))[)
@@ -544,12 +523,11 @@ b4_percent_code_get[]dnl
   ]b4_parser_class_name[::yy_destroy_ (const char* yymsg,
                                        symbol_base_type<Exact>& yysym) const
   {
-    int yytype = yysym.type_get ();
-    YYUSE (yymsg);
     if (yymsg)
       YY_SYMBOL_PRINT (yymsg, yysym);
 
     // User destructor.
+    int yytype = yysym.type_get ();
     switch (yytype)
       {
 ]b4_symbol_foreach([b4_symbol_destructor])dnl
@@ -561,12 +539,14 @@ b4_percent_code_get[]dnl
   b4_symbol_variant([[yytype]], [[yysym.value]], [[template destroy]])])[
   }
 
-#if YYDEBUG
+#if ]b4_api_PREFIX[DEBUG
   template <typename Exact>
   void
   ]b4_parser_class_name[::yy_print_ (std::ostream& yyo,
                                      const symbol_base_type<Exact>& yysym) const
   {
+    std::ostream& yyoutput = yyo;
+    YYUSE (yyoutput);
     int yytype = yysym.type_get ();
     yyo << (yytype < yyntokens_ ? "token" : "nterm")
         << ' ' << yytname_[yytype] << " ("]b4_locations_if([
@@ -575,7 +555,7 @@ b4_percent_code_get[]dnl
       {
 ]b4_symbol_foreach([b4_symbol_printer])dnl
 [       default:
-         break;
+          break;
       }
     yyo << ')';
   }
@@ -588,13 +568,13 @@ b4_percent_code_get[]dnl
     if (m)
       YY_SYMBOL_PRINT (m, sym);
 ]b4_variant_if(
-[[    yystack_.push (stack_symbol_type (]b4_args(
+[[    yystack_.push (stack_symbol_type (]b4_join(
                     [s],
                     [semantic_type()],
                     b4_locations_if([sym.location]))[));
     ]b4_symbol_variant([[yystos_[s]]], [[yystack_[0].value]],
                        [build], [sym.value])],
-[[    yystack_.push (stack_symbol_type (]b4_args(
+[[    yystack_.push (stack_symbol_type (]b4_join(
                       [s],
                       [sym.value],
                       b4_locations_if([sym.location]))[));]])[
@@ -606,7 +586,7 @@ b4_percent_code_get[]dnl
     if (m)
       YY_SYMBOL_PRINT (m, s);
 ]b4_variant_if(
-[[    yystack_.push (stack_symbol_type (]b4_args(
+[[    yystack_.push (stack_symbol_type (]b4_join(
                        [s.state],
                        [semantic_type()],
                        b4_locations_if([s.location]))[));
@@ -621,7 +601,7 @@ b4_percent_code_get[]dnl
     yystack_.pop (n);
   }
 
-#if YYDEBUG
+#if ]b4_api_PREFIX[DEBUG
   std::ostream&
   ]b4_parser_class_name[::debug_stream () const
   {
@@ -646,7 +626,7 @@ b4_percent_code_get[]dnl
   {
     yydebug_ = l;
   }
-#endif
+#endif // ]b4_api_PREFIX[DEBUG
 
   inline ]b4_parser_class_name[::state_type
   ]b4_parser_class_name[::yy_lr_goto_state_ (state_type yystate, int yylhs)
@@ -676,11 +656,11 @@ b4_percent_code_get[]dnl
     /// Whether yyla contains a lookahead.
     bool yyempty = true;
 
-    /* State.  */
+    // State.
     int yyn;
     int yylen = 0;
 
-    /* Error handling.  */
+    // Error handling.
     int yynerrs_ = 0;
     int yyerrstatus_ = 0;
 
@@ -693,25 +673,27 @@ b4_percent_code_get[]dnl
     /// $$ and @@$.
     stack_symbol_type yylhs;
 
-    /// The return value of parse().
+    /// The return value of parse ().
     int yyresult;
 
+    // FIXME: This shoud be completely indented.  It is not yet to
+    // avoid gratuitous conflicts when merging into the master branch.
+    try
+      {
     YYCDEBUG << "Starting parse" << std::endl;
 
 ]m4_ifdef([b4_initial_action], [
-m4_pushdef([b4_at_dollar],     [yyla.location])dnl
-m4_pushdef([b4_dollar_dollar], [yyla.value])dnl
+b4_dollar_pushdef([yyla.value], [], [yyla.location])dnl
     /* User initialization code.  */
     b4_user_initial_action
-m4_popdef([b4_dollar_dollar])dnl
-m4_popdef([b4_at_dollar])])dnl
+b4_dollar_popdef])[]dnl
 
   [  /* Initialize the stack.  The initial state will be set in
        yynewstate, since the latter expects the semantical and the
        location values to have been already stored, initialize these
        stacks with a primary value.  */
     yystack_ = stack_type (0);
-    yypush_ (0, 0, yyla);
+    yypush_ (YY_NULL, 0, yyla);
 
     // A new symbol was pushed on the stack.
   yynewstate:
@@ -735,13 +717,21 @@ m4_popdef([b4_at_dollar])])dnl
     if (yyempty)
       {
         YYCDEBUG << "Reading a token: ";
-]b4_lex_symbol_if(
-[        yyla = b4_c_function_call([yylex], [symbol_type],
-                                   m4_ifdef([b4_lex_param], b4_lex_param));],
-[        yyla.type = yytranslate_ (b4_c_function_call([yylex], [int],
-                                    [[YYSTYPE*], [&yyla.value]][]dnl
+        try
+          {
+]b4_token_ctor_if(
+[            yyla = b4_function_call([yylex], [symbol_type],
+                                     m4_ifdef([b4_lex_param], b4_lex_param));],
+[            yyla.type = yytranslate_ (b4_function_call([yylex], [int],
+                                     [b4_api_PREFIX[STYPE*], [&yyla.value]][]dnl
 b4_locations_if([, [[location*], [&yyla.location]]])dnl
 m4_ifdef([b4_lex_param], [, ]b4_lex_param)));])[
+          }
+        catch (const syntax_error& yyexc)
+          {
+            error (yyexc);
+            goto yyerrlab1;
+          }
         yyempty = false;
       }
     YY_SYMBOL_PRINT ("Next token is", yyla);
@@ -756,10 +746,10 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param)));])[
     yyn = yytable_[yyn];
     if (yyn <= 0)
       {
-       if (yy_table_value_is_error_ (yyn))
-         goto yyerrlab;
-       yyn = -yyn;
-       goto yyreduce;
+        if (yy_table_value_is_error_ (yyn))
+          goto yyerrlab;
+        yyn = -yyn;
+        goto yyreduce;
       }
 
     /* Discard the token being shifted.  */
@@ -814,20 +804,19 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param)));])[
     // Perform the reduction.
     YY_REDUCE_PRINT (yyn);
     try
-    {
-      switch (yyn)
       {
+        switch (yyn)
+          {
 ]b4_user_actions[
-       default:
-          break;
+          default:
+            break;
+          }
       }
-    }
     catch (const syntax_error& yyexc)
-    {
-      error (]b4_args(b4_locations_if([yyexc.location]),
-                      [[yyexc.what()]])[);
-      YYERROR;
-    }
+      {
+        error (yyexc);
+        YYERROR;
+      }
     YY_SYMBOL_PRINT ("-> $$ =", yylhs);
 ]b4_variant_if([[
     // Destroy the rhs symbols.
@@ -835,21 +824,21 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param)));])[
       // Destroy a variant which value may have been swapped with
       // yylhs.value (for instance if the action was "std::swap($$,
       // $1)").  The value of yylhs.value (hence possibly one of these
-      // rhs symbols) depends on the default contruction for this
+      // rhs symbols) depends on the default construction for this
       // type.  In the case of pointers for instance, no
       // initialization is done, so the value is junk.  Therefore do
       // not try to report the value of symbols about to be destroyed
       // in the debug trace, it's possibly junk.  Hence yymsg = 0.
       // Besides, that keeps exactly the same traces as with the other
       // Bison skeletons.
-      yy_destroy_ (0, yystack_[i]);]])[
+      yy_destroy_ (YY_NULL, yystack_[i]);]])[
 
     yypop_ (yylen);
     yylen = 0;
     YY_STACK_PRINT ();
 
     /* Shift the result of the reduction.  */
-    yypush_ (0, yylhs);
+    yypush_ (YY_NULL, yylhs);
     goto yynewstate;
 
   /*--------------------------------------.
@@ -859,8 +848,8 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param)));])[
     /* If not already recovering from an error, report this error.  */
     if (!yyerrstatus_)
       {
-       ++yynerrs_;
-       error (]b4_args(b4_locations_if([yyla.location]),
+        ++yynerrs_;
+        error (]b4_join(b4_locations_if([yyla.location]),
                         [[yysyntax_error_ (yystack_[0].state,
                                            yyempty ? yyempty_ : yyla.type)]])[);
       }
@@ -869,7 +858,7 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param)));])[
     yyerror_range[1].location = yyla.location;]])[
     if (yyerrstatus_ == 3)
       {
-       /* If just tried and failed to reuse lookahead token after an
+        /* If just tried and failed to reuse lookahead token after an
            error, discard it.  */
 
         /* Return failure if at end of input.  */
@@ -879,7 +868,7 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param)));])[
           {
             yy_destroy_ ("Error: discarding", yyla);
             yyempty = true;
-         }
+          }
       }
 
     /* Else will try to reuse lookahead token after shifting the error
@@ -910,7 +899,7 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param)));])[
   | yyerrlab1 -- common code for both syntax error and YYERROR.  |
   `-------------------------------------------------------------*/
   yyerrlab1:
-    yyerrstatus_ = 3;  /* Each real token shifted decrements this.  */
+    yyerrstatus_ = 3;   /* Each real token shifted decrements this.  */
     {
       stack_symbol_type error_token;
       for (;;)
@@ -963,14 +952,38 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param)));])[
     /* Do not reclaim the symbols of the rule which action triggered
        this YYABORT or YYACCEPT.  */
     yypop_ (yylen);
-    while (yystack_.size () != 1)
+    while (1 < yystack_.size ())
       {
-       yy_destroy_ ("Cleanup: popping", yystack_[0]);
-       yypop_ ();
+        yy_destroy_ ("Cleanup: popping", yystack_[0]);
+        yypop_ ();
       }
 
     return yyresult;
   }
+    catch (...)
+      {
+        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 (!yyempty)
+          yy_destroy_ (YY_NULL, yyla);
+
+        while (1 < yystack_.size ())
+          {
+            yy_destroy_ (YY_NULL, yystack_[0]);
+            yypop_ ();
+          }
+        throw;
+      }
+  }
+
+  void
+  ]b4_parser_class_name[::error (const syntax_error& yyexc)
+  {
+    error (]b4_join(b4_locations_if([yyexc.location]),
+                    [[yyexc.what()]])[);
+  }
 
   // Generate an error message.
   std::string
@@ -1040,7 +1053,7 @@ b4_error_verbose_if([state_type yystate, int yytoken],
           }
       }
 
-    char const* yyformat = 0;
+    char const* yyformat = YY_NULL;
     switch (yycount)
       {
 #define YYCASE_(N, S)                         \
@@ -1077,7 +1090,7 @@ b4_error_verbose_if([state_type yystate, int yytoken],
 
 ]b4_parser_tables_define[
 
-#if YYDEBUG || YYERROR_VERBOSE || YYTOKEN_TABLE
+]b4_token_table_if([], [[#if ]b4_api_PREFIX[DEBUG]])[
   /* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
      First, the terminals, then, starting at \a yyntokens_, nonterminals.  */
   const char*
@@ -1085,9 +1098,8 @@ b4_error_verbose_if([state_type yystate, int yytoken],
   {
   ]b4_tname[
   };
-#endif
 
-#if YYDEBUG
+]b4_token_table_if([[#if ]b4_api_PREFIX[DEBUG]])[
 ]b4_integral_parser_table_define([rline], [b4_rline])[
 
   // Print the state stack on the debug stream.
@@ -1098,7 +1110,7 @@ b4_error_verbose_if([state_type yystate, int yytoken],
     for (stack_type::const_iterator
            i = yystack_.begin (),
            i_end = yystack_.end ();
-        i != i_end; ++i)
+         i != i_end; ++i)
       *yycdebug_ << ' ' << i->state;
     *yycdebug_ << std::endl;
   }
@@ -1111,16 +1123,18 @@ b4_error_verbose_if([state_type yystate, int yytoken],
     int yynrhs = yyr2_[yyrule];
     /* Print the symbols being reduced, and their result.  */
     *yycdebug_ << "Reducing stack by rule " << yyrule - 1
-              << " (line " << yylno << "):" << std::endl;
+               << " (line " << yylno << "):" << std::endl;
     /* The symbols being reduced.  */
     for (int yyi = 0; yyi < yynrhs; yyi++)
       YY_SYMBOL_PRINT ("   $" << yyi + 1 << " =",
                        ]b4_rhs_data(yynrhs, yyi + 1)[);
   }
-#endif // YYDEBUG
+#endif // ]b4_api_PREFIX[DEBUG
 
-]b4_lex_symbol_if([], [b4_yytranslate_define])[
+]b4_token_ctor_if([], [b4_yytranslate_define])[
 ]b4_namespace_close[
 ]b4_epilogue[]dnl
-m4_divert_pop(0)
+b4_output_end()
+
+
 m4_popdef([b4_copyright_years])dnl