]> git.saurik.com Git - bison.git/blobdiff - data/lalr1.cc
Make it easier to move the definition of yytranslate_.
[bison.git] / data / lalr1.cc
index ef5aad8e2186181a0e4577a6e669aa82b1b5d29c..d6a48780fd3f7d7e543624b4555a8449830e4fcb 100644 (file)
-m4_divert(-1)
 # C++ skeleton for Bison
-# Copyright (C) 2002, 2003, 2004 Free Software Foundation, Inc.
 
-# This program is free software; you can redistribute it and/or modify
+# Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008
+# Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
-# the Free Software Foundation; either version 2 of the License, or
+# the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
-
+#
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
-
+#
 # You should have received a copy of the GNU General Public License
-# along with this program; if not, write to the Free Software
-# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
-# 02111-1307  USA
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-## ---------------- ##
-## Default values.  ##
-## ---------------- ##
+m4_include(b4_pkgdatadir/[c++.m4])
 
-# Default Parser class name.
-m4_define_default([b4_parser_class_name], [Parser])
 
-
-
-## ----------------- ##
-## Semantic Values.  ##
-## ----------------- ##
+# b4_args(ARG1, ...)
+# _b4_args(ARG1, ...)
+# -------------------
+# Join with comma, skipping empty arguments.
+# b4_args calls itself recursively until it sees the first non-empty
+# argument, then calls _b4_args which prepends each non-empty argument
+# with a comma.
+m4_define([b4_args],
+[m4_if([$#$1],
+       [1], [],
+       [m4_ifval([$1],
+                 [$1[]_$0(m4_shift($@))],
+                 [$0(m4_shift($@))])])])
+
+# _b4_args(ARGS1, ...)
+# --------------------
+m4_define([_b4_args],
+[m4_if([$#$1],
+       [1], [],
+       [m4_ifval([$1], [, $1])[]$0(m4_shift($@))])])
+
+
+# b4_table_define(TABLE-NAME, CONTENT)
+# ------------------------------------
+# Define "parser::yy<TABLE-NAME>_" which contents is CONTENT.
+m4_define([b4_table_define],
+[const b4_int_type_for([$2])
+  b4_parser_class_name::yy$1_[[]] =
+  {
+  $2
+  }dnl
+])
+
+# b4_symbol_value_template(VAL, [TYPE])
+# -------------------------------------
+# Same as b4_symbol_value, but used in a template method.
+m4_copy([b4_symbol_value], [b4_symbol_value_template])
+
+# How the semantic value is extracted when using variants.
+b4_variant_if([
+  # b4_symbol_value(VAL, [TYPE])
+  # ----------------------------
+  m4_define([b4_symbol_value],
+  [m4_ifval([$2],
+            [$1.as<$2>()],
+            [$1])])
+
+  # b4_symbol_value_template(VAL, [TYPE])
+  # -------------------------------------
+  # Same as b4_symbol_value, but used in a template method.
+  m4_define([b4_symbol_value_template],
+  [m4_ifval([$2],
+            [$1.template as<$2>()],
+            [$1])])
+]) # b4_variant_if
+
+
+# b4_lex_symbol_if([IF-YYLEX-RETURNS-A-COMPLETE-SYMBOL], [IF-NOT])
+# ----------------------------------------------------------------
+m4_define([b4_lex_symbol_if],
+[b4_percent_define_ifdef([[lex_symbol]], [$1], [$2])])
+
+
+# b4_assert_if([IF-ASSERTIONS-ARE-USED], [IF-NOT])
+# ------------------------------------------------
+m4_define([b4_assert_if],
+[b4_percent_define_ifdef([[assert]], [$1], [$2])])
 
 
 # b4_lhs_value([TYPE])
 # --------------------
 # Expansion of $<TYPE>$.
 m4_define([b4_lhs_value],
-[yyval[]m4_ifval([$1], [.$1])])
+[b4_symbol_value([yylhs.value], [$1])])
+
+
+# b4_lhs_location()
+# -----------------
+# Expansion of @$.
+m4_define([b4_lhs_location],
+[yylhs.location])
+
+
+# b4_rhs_data(RULE-LENGTH, NUM)
+# -----------------------------
+# Return the data corresponding to the symbol #NUM, where the current
+# rule has RULE-LENGTH symbols on RHS.
+m4_define([b4_rhs_data],
+          [yystack_@{($1) - ($2)@}])
+
+
+# b4_rhs_state(RULE-LENGTH, NUM)
+# -----------------------------
+# The state corresponding to the symbol #NUM, where the current
+# rule has RULE-LENGTH symbols on RHS.
+m4_define([b4_rhs_state],
+          [b4_rhs_data([$1], [$2]).state])
 
 
 # b4_rhs_value(RULE-LENGTH, NUM, [TYPE])
@@ -43,15 +123,7 @@ m4_define([b4_lhs_value],
 # Expansion of $<TYPE>NUM, where the current rule has RULE-LENGTH
 # symbols on RHS.
 m4_define([b4_rhs_value],
-[semantic_stack_@{m4_eval([$1 - $2])@}m4_ifval([$3], [.$3])])
-
-m4_define_default([b4_location_type], [Location])
-
-# b4_lhs_location()
-# -----------------
-# Expansion of @$.
-m4_define([b4_lhs_location],
-[yyloc])
+          [b4_symbol_value([b4_rhs_data([$1], [$2]).value], [$3])])
 
 
 # b4_rhs_location(RULE-LENGTH, NUM)
@@ -59,903 +131,1504 @@ m4_define([b4_lhs_location],
 # Expansion of @NUM, where the current rule has RULE-LENGTH symbols
 # on RHS.
 m4_define([b4_rhs_location],
-[location_stack_@{m4_eval([$1 - $2])@}])
+          [b4_rhs_data([$1], [$2]).location])
+
+
+# b4_symbol(NUM, FIELD)
+# ---------------------
+# Recover a FIELD about symbol #NUM.  Thanks to m4_indir, fails if
+# undefined.
+m4_define([b4_symbol],
+[m4_indir([b4_symbol($1, $2)])])
+
+
+# b4_symbol_if(NUM, FIELD, IF-TRUE, IF-FALSE)
+# -------------------------------------------
+# If FIELD about symbol #NUM is 1 expand IF-TRUE, if is 0, expand IF-FALSE.
+# Otherwise an error.
+m4_define([b4_symbol_if],
+[m4_case(b4_symbol([$1], [$2]),
+         [1], [$3],
+         [0], [$4],
+         [m4_fatal([$0: field $2 of $1 is not a Boolean:] b4_symbol([$1], [$2]))])])
+
+
+# b4_symbol_actions(FILENAME, LINENO,
+#                   SYMBOL-TAG, SYMBOL-NUM,
+#                   SYMBOL-ACTION, SYMBOL-TYPENAME)
+# -------------------------------------------------
+# Same as in C, but using references instead of pointers.
+m4_define([b4_symbol_actions],
+[m4_pushdef([b4_dollar_dollar],
+            [b4_symbol_value_template([yysym.value], [$6])])dnl
+m4_pushdef([b4_at_dollar], [yysym.location])dnl
+      case $4: // $3
+b4_syncline([$2], [$1])
+        $5;
+b4_syncline([@oline@], [@ofile@])
+        break;
+m4_popdef([b4_at_dollar])dnl
+m4_popdef([b4_dollar_dollar])dnl
+])
+
+
+# b4_symbol_case_(SYMBOL-NUM)
+# ---------------------------
+# Issue a "case NUM" for SYMBOL-NUM.
+m4_define([b4_symbol_case_],
+[      case b4_symbol([$1], [number]): // b4_symbol([$1], [tag])
+])
+
+
+# b4_type_action_(NUMS)
+# ---------------------
+# Run actions for the symbol NUMS that all have the same type-name.
+# Skip NUMS that have no type-name.
+m4_define([b4_type_action_],
+[b4_symbol_if([$1], [has_type],
+[m4_map([b4_symbol_case_], [$@])[]dnl
+        b4_dollar_dollar([b4_symbol([$1], [number])],
+                         [b4_symbol([$1], [tag])],
+                         [b4_symbol([$1], [type])]);
+       break;
+
+])])
+
+
+# b4_symbol_constructor_declaration_(SYMBOL-NUMBERS)
+# ----------------------------------------------------
+# Declare the overloaded version of make_symbol for the (common) type of
+# these SYMBOL-NUMBERS.  Use at class-level.
+m4_define([b4_symbol_constructor_declaration_],
+[    template <token_type>
+    static inline symbol_type
+    make_symbol (b4_args(b4_symbol_if([$1], [has_type],
+                                      [const b4_symbol([$1], [type])& v]),
+                         b4_locations_if([const location_type& l])));
+
+])
+
+# b4_symbol_constructor_declarations
+# ----------------------------------
+# Declare the overloaded versions of make_symbol for all the value types.
+# Use at class-level.
+m4_define([b4_symbol_constructor_declarations],
+[b4_variant_if([
+    // Declaration of make_symbol for each value type.
+m4_map([b4_symbol_constructor_declaration_], m4_defn([b4_type_names]))])])
+
+
+
+# b4_symbol_constructor_specialization_(SYMBOL-NUMBER)
+# ----------------------------------------------------
+# Declare the specialization of make_symbol for this each SYMBOL-NUMBER.
+# Specializations cannot be declared at class-level, this must be done
+# at namespace-level.
+m4_define([b4_symbol_constructor_specialization_],
+[b4_symbol_if([$1], [is_token], [b4_symbol_if([$1], [has_id],
+[  template <>
+  inline
+  b4_parser_class_name::symbol_type
+  b4_parser_class_name::make_symbol <b4_parser_class_name::token::b4_symbol([$1], [id])> (dnl
+b4_args(b4_symbol_if([$1], [has_type],
+                     [const b4_symbol([$1], [type])& v]),
+        b4_locations_if([const location_type& l])));
+])])])
+
+# b4_symbol_constructor_specializations
+# -------------------------------------
+# Declare specializations of make_symbol.
+m4_define([b4_symbol_constructor_specializations],
+[b4_variant_if([
+  // Specializations of make_symbol for each symbol type.
+m4_map([b4_symbol_constructor_specialization_],
+       m4_defn([b4_symbol_numbers]))])dnl
+])
+
+
+
+# b4_symbol_constructor_definition_(SYMBOL-NUMBER)
+# ------------------------------------------------
+# Define make_symbol for this SYMBOL-NUMBER.
+m4_define([b4_symbol_constructor_definition_],
+[b4_symbol_if([$1], [is_token], [b4_symbol_if([$1], [has_id],
+[  template <>
+  b4_parser_class_name::symbol_type
+  b4_parser_class_name::make_symbol <b4_parser_class_name::token::b4_symbol([$1], [id])> (dnl
+b4_args(b4_symbol_if([$1], [has_type],
+                     [const b4_symbol([$1], [type])& v]),
+        b4_locations_if([const location_type& l])))
+  {
+    return symbol_type (b4_args([yytranslate_ (token::b4_symbol([$1], [id]))],
+                                b4_symbol_if([$1], [has_type], [v]),
+                                b4_locations_if([l])));
+  }
 
+])])])
 
-m4_define([b4_inherit],
-          [m4_ifdef([b4_root],
-                   [: public b4_root
-],
-                   [])])
 
-m4_define([b4_param],
-         [m4_ifdef([b4_root],
-                   [,
-            const Param& param],
-                   [])])
+# b4_symbol_constructor_declarations
+# ----------------------------------
+# Define the overloaded versions of make_symbol for all the value types.
+m4_define([b4_symbol_constructor_definitions],
+[b4_variant_if(
+[  // Implementation of make_symbol for each symbol type.
+m4_map([b4_symbol_constructor_definition_], m4_defn([b4_symbol_numbers]))])])
 
-m4_define([b4_constructor],
-         [m4_ifdef([b4_root],
-                   [b4_root (param),
-      ],
-                   [])])
 
+# b4_symbol_variant(YYTYPE, YYVAL, ACTION, [ARGS])
+# ------------------------------------------------
+# Run some ACTION ("build", or "destroy") on YYVAL of symbol type
+# YYTYPE.
+m4_define([b4_symbol_variant],
+[m4_pushdef([b4_dollar_dollar],
+            [$2.$3<$][3>(m4_shift3($@))])dnl
+  switch ($1)
+    {
+m4_map([b4_type_action_], m4_defn([b4_type_names]))[]dnl
+      default:
+        break;
+    }
+m4_popdef([b4_dollar_dollar])dnl
+])
+
+
+# _b4_char_sizeof_counter
+# -----------------------
+# A counter used by _b4_char_sizeof_dummy to create fresh symbols.
+m4_define([_b4_char_sizeof_counter],
+[0])
+
+# _b4_char_sizeof_dummy
+# ---------------------
+# At each call return a new C++ identifier.
+m4_define([_b4_char_sizeof_dummy],
+[m4_define([_b4_char_sizeof_counter], m4_incr(_b4_char_sizeof_counter))dnl
+dummy[]_b4_char_sizeof_counter])
+
+
+# b4_char_sizeof_(SYMBOL-NUM)
+# ---------------------------
+# A comment describing this symbol.
+m4_define([b4_char_sizeof_],
+[      // b4_symbol([$1], [tag])
+])
+
+# b4_char_sizeof(SYMBOL-NUMS)
+# --------------------------
+# To be mapped on the list of type names to produce:
+#
+#    char dummy1[sizeof(type_name_1)];
+#    char dummy2[sizeof(type_name_2)];
+#
+# for defined type names.
+m4_define([b4_char_sizeof],
+[b4_symbol_if([$1], [has_type],
+[
+m4_map([b4_char_sizeof_], [$@])dnl
+      char _b4_char_sizeof_dummy@{sizeof([b4_symbol([$1], [type])])@};
+])])
+
+
+# b4_yytranslate_definition
+# -------------------------
+# Define yytranslate_.  Sometimes we want it in the header file,
+# sometimes the cc file suffices.
+m4_define([b4_yytranslate_definition],
+[[  // YYTRANSLATE(YYLEX) -- Bison symbol number corresponding to YYLEX.
+  ]b4_parser_class_name[::token_number_type
+  ]b4_parser_class_name[::yytranslate_ (]b4_lex_symbol_if([token_type],
+                                                          [int])[ t)
+  {
+    static
+    const token_number_type
+    translate_table[] =
+    {
+]b4_translate[
+    };
+    const unsigned 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_)
+      return yyeof_;
+    else if (static_cast<unsigned int> (t) <= user_token_number_max_)
+      return translate_table[t];
+    else
+      return undef_token_;
+  }
+]])
 
-# b4_parse_param_decl
-# -------------------
-#  Constructor's extra arguments.
-m4_define([b4_parse_param_decl],
-          [m4_ifset([b4_parse_param], [, b4_c_ansi_formals(b4_parse_param)])])
 
-# b4_parse_param_cons
-# -------------------
-#  constructor's extra initialisations.
-m4_define([b4_parse_param_cons],
-          [m4_ifset([b4_parse_param],
-                   [,
-      b4_cc_constructor_calls(b4_parse_param)])])
-m4_define([b4_cc_constructor_calls],
-         [m4_map_sep([b4_cc_constructor_call], [,
-      ], [$@])])
-m4_define([b4_cc_constructor_call],
-         [$2($2)])
-
-# b4_parse_param_vars
-# -------------------
-#  Extra instance variables.
-m4_define([b4_parse_param_vars],
-          [m4_ifset([b4_parse_param],
-                   [
-    /* User arguments.  */
-b4_cc_var_decls(b4_parse_param)])])
-m4_define([b4_cc_var_decls],
-         [m4_map_sep([b4_cc_var_decl], [
-], [$@])])
-m4_define([b4_cc_var_decl],
-         [    $1;])
+m4_pushdef([b4_copyright_years],
+           [2002, 2003, 2004, 2005, 2006, 2007, 2008])
 
+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(
+[# Backward compatibility.
+m4_define([b4_location_constructors])
+m4_include(b4_pkgdatadir/[location.cc])])
 
 # We do want M4 expansion after # for CPP macros.
 m4_changecom()
-m4_divert(0)dnl
-m4_if(b4_defines_flag, 0, [],
-[@output @output_header_name@
-b4_copyright([C++ Skeleton parser for LALR(1) parsing with Bison],
-             [2002, 2003, 2004])[
-/* FIXME: This is wrong, we want computed header guards.
-   I don't know why the macros are missing now. :( */
+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
 
-#include "stack.hh"
-#include "location.hh"
+]b4_percent_code_get([[requires]])[
 
+]b4_assert_if([#include <cassert>])[
 #include <string>
 #include <iostream>
+#include "stack.hh"
+
+]b4_namespace_open[
+]b4_locations_if([  class position;
+  class location;])[
+]b4_variant_if(
+[[
+  /// A char[S] buffer to store and retrieve objects.
+  ///
+  /// Sort of a variant, but does not keep track of the nature
+  /// of the stored data, since that knowledge is available
+  /// via the current state.
+  template <size_t S>
+  struct variant
+  {]b4_assert_if([
+    /// Whether something is contained.
+    bool built;
+])[
+    /// Empty construction.
+    inline
+    variant ()]b4_assert_if([
+      : built(false)])[
+    {}
+
+    /// Instantiate a \a T in here.
+    template <typename T>
+    inline T&
+    build()
+    {]b4_assert_if([
+      assert(!built);
+      built = true;])[
+      return *new (buffer) T;
+    }
 
-/* Using locations.  */
-#define YYLSP_NEEDED ]b4_locations_flag[
+    /// Instantiate a \a T in here from \a t.
+    template <typename T>
+    inline T&
+    build(const T& t)
+    {]b4_assert_if([
+      assert(!built);
+      built = true;])[
+      return *new (buffer) T(t);
+    }
 
-]b4_token_defines(b4_tokens)[
+    /// Construct and fill.
+    template <typename T>
+    inline
+    variant (const T& t)]b4_assert_if([
+      : built(true)])[
+    {
+      new (buffer) T(t);
+    }
 
-/* Copy the first part of user declarations.  */
-]b4_pre_prologue[
+    /// Accessor to a built \a T.
+    template <typename T>
+    inline T&
+    as()
+    {]b4_assert_if([
+      assert(built);])[
+      return reinterpret_cast<T&>(buffer);
+    }
 
-]/* Line __line__ of lalr1.cc.  */
-b4_syncline([@oline@], [@ofile@])[
+    /// Const accessor to a built \a T (for %printer).
+    template <typename T>
+    inline const T&
+    as() const
+    {]b4_assert_if([
+      assert(built);])[
+      return reinterpret_cast<const T&>(buffer);
+    }
 
-/* Enabling traces.  */
-#ifndef YYDEBUG
-# define YYDEBUG ]b4_debug[
-#endif
+    /// Swap the content with \a other.
+    template <typename T>
+    inline void
+    swap(variant<S>& other)
+    {
+      std::swap(as<T>(), other.as<T>());
+    }
 
-/* Enabling verbose error message.  */
-#ifndef YYERROR_VERBOSE
-# define YYERROR_VERBOSE ]b4_error_verbose[
-#endif
+    /// Assign the content of \a other to this.
+    /// Destroys \a other.
+    template <typename T>
+    inline void
+    build(variant<S>& other)
+    {
+      build<T>();
+      swap<T>(other);
+      other.destroy<T>();
+    }
 
-#ifdef YYSTYPE
-typedef YYSTYPE yystype;
-#else
-]m4_ifdef([b4_stype],
-[b4_syncline([b4_stype_line], [b4_filename])
-typedef union b4_stype yystype;
-/* Line __line__ of lalr1.cc.  */
-b4_syncline([@oline@], [@ofile@])],
-[typedef int yystype;])[
-# define YYSTYPE yystype
-#endif
+    /// Destroy the stored \a T.
+    template <typename T>
+    inline void
+    destroy()
+    {
+      as<T>().~T();]b4_assert_if([
+      built = false;])[
+    }
 
-/* Copy the second part of user declarations.  */
-]b4_post_prologue[
+    /// A buffer large enough to store any of the semantic values.
+    char buffer[S];
+  };
+]])[
+]b4_namespace_close[
 
-]/* Line __line__ of lalr1.cc.  */
-b4_syncline([@oline@], [@ofile@])[
-/* YYLLOC_DEFAULT -- Set CURRENT to span from RHS[1] to RHS[N].  */
+]b4_locations_if([#include "location.hh"])[
 
-#ifndef YYLLOC_DEFAULT
-# define YYLLOC_DEFAULT(Current, Rhs, N)       \
-do {                                           \
-   ((Current).begin = (Rhs)[1].begin);         \
-   ((Current).end   = (Rhs)[N].end);           \
-} while (0)
+/* Enabling traces.  */
+#ifndef YYDEBUG
+# define YYDEBUG ]b4_debug_flag[
 #endif
 
-namespace yy
-{
-  class ]b4_parser_class_name[;
+/* Enabling verbose error messages.  */
+#ifdef YYERROR_VERBOSE
+# undef YYERROR_VERBOSE
+# define YYERROR_VERBOSE 1
+#else
+# define YYERROR_VERBOSE ]b4_error_verbose_flag[
+#endif
 
-  template < typename P >
-  struct Traits
-  {
-  };
+/* Enabling the token table.  */
+#ifndef YYTOKEN_TABLE
+# define YYTOKEN_TABLE ]b4_token_table[
+#endif
 
-  template < >
-  struct Traits< ]b4_parser_class_name[ >
-  {
-    typedef ]b4_int_type_for([b4_translate])[ TokenNumberType;
-    typedef ]b4_int_type_for([b4_rhs])[       RhsNumberType;
-    typedef int      StateType;
-    typedef yystype  SemanticType;
-    typedef ]b4_location_type[ LocationType;
-  };
-}
+]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).  */
 
-namespace yy
-{
-  class ]b4_parser_class_name b4_inherit[
+#ifndef YYLLOC_DEFAULT
+# define YYLLOC_DEFAULT(Current, Rhs, N)                        \
+do {                                                            \
+  if (N)                                                        \
+    {                                                           \
+      (Current).begin = (Rhs)[1].location.begin;                \
+      (Current).end   = (Rhs)[N].location.end;                 \
+    }                                                           \
+  else                                                          \
+    {                                                           \
+      (Current).begin = (Current).end = (Rhs)[0].location.end; \
+    }                                                           \
+} while (false)
+#endif]])[
+
+]b4_namespace_open[
+
+  /// A Bison parser.
+  class ]b4_parser_class_name[
   {
   public:
-
-    typedef Traits< ]b4_parser_class_name[ >::TokenNumberType TokenNumberType;
-    typedef Traits< ]b4_parser_class_name[ >::RhsNumberType   RhsNumberType;
-    typedef Traits< ]b4_parser_class_name[ >::StateType       StateType;
-    typedef Traits< ]b4_parser_class_name[ >::SemanticType    SemanticType;
-    typedef Traits< ]b4_parser_class_name[ >::LocationType    LocationType;
-
-    typedef Stack< StateType >    StateStack;
-    typedef Stack< SemanticType > SemanticStack;
-    typedef Stack< LocationType > LocationStack;
-
-#if YYLSP_NEEDED
-    ]b4_parser_class_name[ (bool debug,
-           LocationType initlocation][]b4_param[]b4_parse_param_decl[) :
-      ]b4_constructor[][debug_ (debug),
-      cdebug_ (std::cerr),
-      initlocation_ (initlocation)]b4_parse_param_cons[
+#ifndef YYSTYPE
+]b4_variant_if(
+[    /// An auxiliary type to compute the largest semantic type.
+    union union_type
+    {]m4_map([b4_char_sizeof], m4_defn([b4_type_names]))[};
+
+    /// Symbol semantic values.
+    typedef variant<sizeof(union_type)> semantic_type;],
+[    /// Symbol semantic values.
+m4_ifdef([b4_stype],
+[    union semantic_type
+    {b4_user_stype
+    };],
+[m4_if(b4_tag_seen_flag, 0,
+[[    typedef int semantic_type;]],
+[[    typedef YYSTYPE semantic_type;]])])])[
 #else
-    ]b4_parser_class_name[ (bool debug][]b4_param[]b4_parse_param_decl[) :
-      ]b4_constructor[][debug_ (debug),
-      cdebug_ (std::cerr)]b4_parse_param_cons[
-#endif
+    typedef YYSTYPE semantic_type;
+#endif]b4_locations_if([
+    /// Symbol locations.
+    typedef b4_percent_define_get([[location_type]]) location_type;])[
+    /// Tokens.
+    struct token
     {
-    }
+      ]b4_token_enums(b4_tokens)[
+    };
+    /// Token type.
+    typedef token::yytokentype token_type;
 
-    virtual ~]b4_parser_class_name[ ()
-    {
-    }
+    /// Build a parser object.
+    ]b4_parser_class_name[ (]b4_parse_param_decl[);
+    virtual ~]b4_parser_class_name[ ();
 
+    /// Parse.
+    /// \returns  0 iff parsing succeeded.
     virtual int parse ();
 
-  private:
-
-    virtual void lex_ ();
-    virtual void error_ ();
-    virtual void print_ ();
-    virtual void report_syntax_error_ ();
 #if YYDEBUG
-    virtual void symprint_ (int yytype,
-                           const SemanticType *yyvaluep,
-                           const LocationType *yylocationp);
-#endif /* ! YYDEBUG */
+    /// The current debugging stream.
+    std::ostream& debug_stream () const;
+    /// Set the current debugging stream.
+    void set_debug_stream (std::ostream &);
+
+    /// Type for debugging levels.
+    typedef int debug_level_type;
+    /// The current debugging level.
+    debug_level_type debug_level () const;
+    /// Set the current debugging level.
+    void set_debug_level (debug_level_type l);
+#endif
+
+  private:
+    /// 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);
 
+    /// Generate an error message.
+    /// \param state   the state where the error occurred.
+    /// \param tok     the lookahead token.
+    virtual std::string yysyntax_error_ (int yystate, int tok);
 
-    /* Stacks.  */
-    StateStack    state_stack_;
-    SemanticStack semantic_stack_;
-    LocationStack location_stack_;
+    /// State numbers.
+    typedef int state_type;
 
+    /// Internal symbol numbers.
+    typedef ]b4_int_type_for([b4_translate])[ token_number_type;
     /* Tables.  */
-    static const ]b4_int_type_for([b4_pact])[ pact_[];
-    static const ]b4_int_type(b4_pact_ninf, b4_pact_ninf)[ pact_ninf_;
-    static const ]b4_int_type_for([b4_defact])[ defact_[];
-    static const ]b4_int_type_for([b4_pgoto])[ pgoto_[];
-    static const ]b4_int_type_for([b4_defgoto])[ defgoto_[];
-    static const ]b4_int_type_for([b4_table])[ table_[];
-    static const ]b4_int_type(b4_table_ninf, b4_table_ninf)[ table_ninf_;
-    static const ]b4_int_type_for([b4_check])[ check_[];
-    static const ]b4_int_type_for([b4_stos])[ stos_[];
-    static const ]b4_int_type_for([b4_r1])[ r1_[];
-    static const ]b4_int_type_for([b4_r2])[ r2_[];
-
-#if YYDEBUG || YYERROR_VERBOSE
-    static const char* const name_[];
+    /// For a state, the index in \a yytable_ of its portion.
+    static const ]b4_int_type_for([b4_pact])[ yypact_[];
+    static const ]b4_int_type(b4_pact_ninf, b4_pact_ninf)[ yypact_ninf_;
+
+    /// For a state, default rule to reduce.
+    /// Unless\a  yytable_ specifies something else to do.
+    /// Zero means the default is an error.
+    static const ]b4_int_type_for([b4_defact])[ yydefact_[];
+
+    static const ]b4_int_type_for([b4_pgoto])[ yypgoto_[];
+    static const ]b4_int_type_for([b4_defgoto])[ yydefgoto_[];
+
+    /// What to do in a state.
+    /// \a yytable_[yypact_[s]]: what to do in state \a s.
+    /// - if positive, shift that token.
+    /// - if negative, reduce the rule which number is the opposite.
+    /// - if zero, do what YYDEFACT says.
+    static const ]b4_int_type_for([b4_table])[ yytable_[];
+    static const ]b4_int_type(b4_table_ninf, b4_table_ninf)[ yytable_ninf_;
+
+    static const ]b4_int_type_for([b4_check])[ yycheck_[];
+
+    /// For a state, its accessing symbol.
+    static const ]b4_int_type_for([b4_stos])[ yystos_[];
+
+    /// For a rule, its LHS.
+    static const ]b4_int_type_for([b4_r1])[ yyr1_[];
+    /// For a rule, its RHS length.
+    static const ]b4_int_type_for([b4_r2])[ yyr2_[];
+
+#if YYDEBUG || YYERROR_VERBOSE || YYTOKEN_TABLE
+    /// For a symbol, its name in clear.
+    static const char* const yytname_[];
+#endif]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
+    /// For each rule, its source line number.
+    static const ]b4_int_type_for([b4_rline])[ yyrline_[];
+    /// For each scanner token number, its symbol number.
+    static const ]b4_int_type_for([b4_toknum])[ yytoken_number_[];
+    /// Report on the debug stream that the rule \a r is going to be reduced.
+    virtual void yy_reduce_print_ (int r);
+    /// Print the state stack on the debug stream.
+    virtual void yystack_print_ ();
+
+    /* Debugging.  */
+    int yydebug_;
+    std::ostream* yycdebug_;
 #endif
 
-    /* More tables, for debugging.  */
+    /// Convert a scanner token number \a t to a symbol number.
+    static token_number_type yytranslate_ (]b4_lex_symbol_if([token_type], [int])[ t);
+
+    /// A complete symbol, with its type.
+    template <typename Exact>
+    struct symbol_base_type
+    {
+      /// Default constructor.
+      inline symbol_base_type ();
+
+      /// Constructor.]b4_locations_if([
+      inline symbol_base_type (const location_type& l)])[;
+      inline symbol_base_type (]b4_args(
+        [const semantic_type& v],
+        b4_locations_if([const location_type& l]))[);
+
+      /// Return this with its exact type.
+      const Exact& self () const;
+      Exact& self ();
+
+      /// Return the type of this symbol.
+      int type_get () const;
+
+      /// The semantic value.
+      semantic_type value;]b4_locations_if([
+
+      /// The location.
+      location_type location;])[
+    };
+
 #if YYDEBUG
-    static const RhsNumberType rhs_[];
-    static const ]b4_int_type_for([b4_prhs])[ prhs_[];
-    static const ]b4_int_type_for([b4_rline])[ rline_[];
-    static const ]b4_int_type_for([b4_toknum])[ token_number_[];
-    virtual void reduce_print_ (int yyrule);
-    virtual void stack_print_ ();
+    /// \brief Display a symbol type, value and location.
+    /// \param yyo    The output stream.
+    /// \param yysym  The symbol.
+    template <typename Exact>
+    void yy_print_ (std::ostream& yyo,
+                    const symbol_base_type<Exact>& yysym) const;
 #endif
 
-    /* Even more tables.  */
-    inline TokenNumberType translate_ (int token);
-    inline void destruct_ (const char *yymsg,
-                           int yytype,
-                           SemanticType *yyvaluep, LocationType *yylocationp);
+    /// \brief Reclaim the memory associated to a symbol.
+    /// \param yymsg     Why this token is reclaimed.
+    ///                  If null, print nothing.
+    /// \param s         The symbol.
+    template <typename Exact>
+    inline void yy_destroy_ (const char* yymsg,
+                             symbol_base_type<Exact>& yysym) const;
 
-    /// Pop \a n symbols the three stacks.
-    inline void pop (unsigned int n = 1);
+  public:
+    /// Element of the stack: a state and its attributes.
+    struct symbol_type : symbol_base_type<symbol_type>
+    {
+      /// The parent class.
+      typedef symbol_base_type<symbol_type> super_type;
 
-    /* Constants.  */
-    static const int eof_;
-    /* LAST_ -- Last index in TABLE_.  */
-    static const int last_;
-    static const int nnts_;
-    static const int empty_;
-    static const int final_;
-    static const int terror_;
-    static const int errcode_;
-    static const int ntokens_;
-    static const unsigned int user_token_number_max_;
-    static const TokenNumberType undef_token_;
+      /// Default constructor.
+      inline symbol_type ();
 
-    /* State.  */
-    int n_;
-    int len_;
-    int state_;
+      /// Constructor.
+      inline symbol_type (]b4_args([int t],
+                                   [const semantic_type& v],
+                                   b4_locations_if([const location_type& l]))[);
 
-    /* Error handling. */
-    int nerrs_;
-    int errstatus_;
+      inline symbol_type (]b4_args([int t],
+                                   b4_locations_if([const location_type& l]))[);
 
-    /* Debugging.  */
-    int debug_;
-    std::ostream &cdebug_;
+      /// The symbol type.
+      int type;
 
-    /* Look-ahead and look-ahead in internal form.  */
-    int looka_;
-    int ilooka_;
+      /// Return the type corresponding to this state.
+      inline int type_get_ () const;
+    };
 
-    /* Message.  */
-    std::string message;
+]b4_symbol_constructor_declarations[
 
-    /* Semantic value and location of look-ahead token.  */
-    SemanticType value;
-    LocationType location;
-    /// The locations where the error started and ended.
-    Location error_range_[2];
+  private:
+    /// Element of the stack: a state and its attributes.
+    struct stack_symbol_type : symbol_base_type<stack_symbol_type>
+    {
+      /// The parent class.
+      typedef symbol_base_type<stack_symbol_type> super_type;
+
+      /// Default constructor.
+      inline stack_symbol_type ();
+
+      /// Constructor.
+      inline stack_symbol_type (]b4_args([state_type s],
+                                         [const semantic_type& v],
+                                         b4_locations_if([const location_type& l]))[);
+
+      /// The state.
+      state_type state;
 
-    /* @@$ and $$.  */
-    SemanticType yyval;
-    LocationType yyloc;
+      /// Return the type corresponding to this state.
+      inline int type_get_ () const;
+    };
+
+    /// Stack type.
+    typedef stack<stack_symbol_type> stack_type;
+
+    /// The stack.
+    stack_type yystack_;
+
+    /// Push a new state on the stack.
+    /// \param m    a debug message to display
+    ///             if null, no trace is output.
+    /// \param s    the symbol
+    /// \warning the contents of \a s.value is stolen.
+    inline void yypush_ (const char* m, stack_symbol_type& s);
+
+    /// Push a new look ahead token on the state on the stack.
+    /// \param m    a debug message to display
+    ///             if null, no trace is output.
+    /// \param s    the state
+    /// \param sym  the symbol (for its value and location).
+    /// \warning the contents of \a s.value is stolen.
+    inline void yypush_ (const char* m, state_type s, symbol_type& sym);
+
+    /// Pop \a n symbols the three stacks.
+    inline void yypop_ (unsigned int n = 1);
+
+    /* Constants.  */
+    enum
+    {
+      yyeof_ = 0,
+      yylast_ = ]b4_last[,           //< Last index in yytable_.
+      yynnts_ = ]b4_nterms_number[,  //< Number of nonterminal symbols.
+      yyempty_ = -2,
+      yyfinal_ = ]b4_final_state_number[, //< Termination state number.
+      yyterror_ = 1,
+      yyerrcode_ = 256,
+      yyntokens_ = ]b4_tokens_number[,   //< Number of tokens.
+    };
 
-    /* Initial location.  */
-    LocationType initlocation_;
 ]b4_parse_param_vars[
   };
-}
+]b4_symbol_constructor_specializations[
+]b4_namespace_close[
 
-#endif /* ! defined PARSER_HEADER_H */]
-])dnl
-@output @output_parser_name@
-b4_copyright([C++ Skeleton parser for LALR(1) parsing with Bison],
-             [2002, 2003, 2004])
+]b4_percent_define_flag_if([[global_tokens_and_yystype]],
+[b4_token_defines(b4_tokens)
 
-m4_if(b4_defines_flag, 0, [], [#include @output_header_name@])[
+#ifndef YYSTYPE
+ /* Redirection for backward compatibility.  */
+# define YYSTYPE b4_namespace_ref::b4_parser_class_name::semantic_type
+#endif
+])
+b4_percent_code_get([[provides]])[]dnl
+
+[#endif /* ! defined PARSER_HEADER_H */]
+@output(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], [],
+[
+// Take the name prefix into account.
+#define yylex   b4_prefix[]lex])[
+
+/* First part of user declarations.  */
+]b4_user_pre_prologue[
+
+#include "@basename(]b4_spec_defines_file[@)"
+
+/* User implementation prologue.  */
+]b4_user_post_prologue
+b4_percent_code_get[]dnl
+
+[#ifndef YY_
+# if YYENABLE_NLS
+#  if ENABLE_NLS
+#   include <libintl.h> /* FIXME: INFRINGES ON USER NAME SPACE */
+#   define YY_(msgid) dgettext ("bison-runtime", msgid)
+#  endif
+# endif
+# ifndef YY_
+#  define YY_(msgid) msgid
+# endif
+#endif
+
+/* Suppress unused-variable warnings by "using" E.  */
+#define YYUSE(e) ((void) (e))
 
 /* Enable debugging if requested.  */
 #if YYDEBUG
 
-# define YYCDEBUG                              \
-  if (debug_)                                  \
-    cdebug_
+/* A pseudo ostream that takes yydebug_ into account.  */
+# define YYCDEBUG if (yydebug_) (*yycdebug_)
 
-# define YY_SYMBOL_PRINT(Title, Type, Value, Location) \
-do {                                                   \
-  if (debug_)                                          \
-    {                                                  \
-      cdebug_ << (Title) << ' ';                       \
-      symprint_ ((Type), (Value), (Location));         \
-      cdebug_ << std::endl;                            \
-    }                                                  \
-} while (0)
+# define YY_SYMBOL_PRINT(Title, Symbol)         \
+  do {                                          \
+    if (yydebug_)                               \
+    {                                           \
+      *yycdebug_ << Title << ' ';               \
+      yy_print_ (*yycdebug_, Symbol);           \
+      *yycdebug_ << std::endl;                  \
+    }                                           \
+  } while (false)
 
 # define YY_REDUCE_PRINT(Rule)         \
-do {                                   \
-  if (debug_)                          \
-    reduce_print_ (Rule);              \
-} while (0)
+  do {                                 \
+    if (yydebug_)                       \
+      yy_reduce_print_ (Rule);         \
+  } while (false)
 
 # define YY_STACK_PRINT()              \
-do {                                   \
-  if (debug_)                          \
-    stack_print_ ();                   \
-} while (0)
+  do {                                 \
+    if (yydebug_)                       \
+      yystack_print_ ();                \
+  } while (false)
 
 #else /* !YYDEBUG */
 
-# define YYCDEBUG    if (0) cdebug_
-# define YY_SYMBOL_PRINT(Title, Type, Value, Location)
-# define YY_REDUCE_PRINT(Rule)
-# define YY_STACK_PRINT()
+# define YYCDEBUG if (false) std::cerr
+# define YY_SYMBOL_PRINT(Title, Symbol)  static_cast<void>(0)
+# define YY_REDUCE_PRINT(Rule)           static_cast<void>(0)
+# define YY_STACK_PRINT()                static_cast<void>(0)
 
 #endif /* !YYDEBUG */
 
-#define YYACCEPT       goto yyacceptlab
-#define YYABORT                goto yyabortlab
-#define YYERROR                goto yyerrorlab
+#define yyerrok         (yyerrstatus_ = 0)
+#define yyclearin       (yyempty = true)
+
+#define YYACCEPT        goto yyacceptlab
+#define YYABORT         goto yyabortlab
+#define YYERROR         goto yyerrorlab
+#define YYRECOVERING()  (!!yyerrstatus_)
 
+]b4_namespace_open[]b4_error_verbose_if([[
+
+  /* Return YYSTR after stripping away unnecessary quotes and
+     backslashes, so that it's suitable for yyerror.  The heuristic is
+     that double-quoting is unnecessary unless the string contains an
+     apostrophe, a comma, or backslash (other than backslash-backslash).
+     YYSTR is taken from yytname.  */
+  std::string
+  ]b4_parser_class_name[::yytnamerr_ (const char *yystr)
+  {
+    if (*yystr == '"')
+      {
+        std::string yyr = "";
+        char const *yyp = yystr;
+
+        for (;;)
+          switch (*++yyp)
+            {
+            case '\'':
+            case ',':
+              goto do_not_strip_quotes;
+
+            case '\\':
+              if (*++yyp != '\\')
+                goto do_not_strip_quotes;
+              /* Fall through.  */
+            default:
+              yyr += *yyp;
+              break;
+
+            case '"':
+              return yyr;
+            }
+      do_not_strip_quotes: ;
+      }
+
+    return yystr;
+  }
+]])[
+
+  /// Build a parser object.
+  ]b4_parser_class_name::b4_parser_class_name[ (]b4_parse_param_decl[)]m4_ifset([b4_parse_param], [
+    :])[
 #if YYDEBUG
-/*--------------------------------.
-| Print this symbol on YYOUTPUT.  |
-`--------------------------------*/
-
-void
-yy::]b4_parser_class_name[::symprint_ (int yytype,
-                         const SemanticType *yyvaluep, const LocationType *yylocationp)
-{
-  /* Pacify ``unused variable'' warnings.  */
-  (void) yyvaluep;
-  (void) yylocationp;
-
-  cdebug_ << (yytype < ntokens_ ? "token" : "nterm")
-         << ' ' << name_[yytype] << " ("
-          << *yylocationp << ": ";
-  switch (yytype)
-    {
-]m4_map([b4_symbol_actions], m4_defn([b4_symbol_printers]))dnl
-[      default:
-        break;
-    }
-  cdebug_ << ')';
-}
-#endif /* ! YYDEBUG */
+    ]m4_ifset([b4_parse_param], [  ], [ :])[yydebug_ (false),
+      yycdebug_ (&std::cerr)]m4_ifset([b4_parse_param], [,])[
+#endif]b4_parse_param_cons[
+  {
+  }
 
-void
-yy::]b4_parser_class_name[::destruct_ (const char *yymsg,
-                         int yytype, SemanticType *yyvaluep, LocationType *yylocationp)
-{
-  /* Pacify ``unused variable'' warnings.  */
-  (void) yyvaluep;
-  (void) yylocationp;
+  ]b4_parser_class_name::~b4_parser_class_name[ ()
+  {
+  }
 
-  YY_SYMBOL_PRINT (yymsg, yytype, yyvaluep, yylocationp);
 
-  switch (yytype)
-    {
+  /*---------------.
+  | Symbol types.  |
+  `---------------*/
+
+  // symbol_base_type.
+  template <typename Exact>
+  ]b4_parser_class_name[::symbol_base_type<Exact>::symbol_base_type ()
+    : value()]b4_locations_if([
+    , location()])[
+  {
+  }]b4_locations_if([[
+
+  template <typename Exact>
+  ]b4_parser_class_name[::symbol_base_type<Exact>::symbol_base_type (const location_type& l)
+    : value()
+    , location(l)
+  {
+  }]])[
+
+  template <typename Exact>
+  ]b4_parser_class_name[::symbol_base_type<Exact>::symbol_base_type (]b4_args(
+          [const semantic_type& v],
+          b4_locations_if([const location_type& l]))[)
+    : value(v)]b4_locations_if([
+    , location(l)])[
+  {
+  }
+
+  template <typename Exact>
+  const Exact&
+  ]b4_parser_class_name[::symbol_base_type<Exact>::self () const
+  {
+    return static_cast<const Exact&>(*this);
+  }
+
+  template <typename Exact>
+  Exact&
+  ]b4_parser_class_name[::symbol_base_type<Exact>::self ()
+  {
+    return static_cast<Exact&>(*this);
+  }
+
+  template <typename Exact>
+  int
+  ]b4_parser_class_name[::symbol_base_type<Exact>::type_get () const
+  {
+    return self ().type_get_ ();
+  }
+
+  // symbol_type.
+  ]b4_parser_class_name[::symbol_type::symbol_type ()
+    : super_type ()
+    , type ()
+  {
+  }
+
+  ]b4_parser_class_name[::symbol_type::symbol_type (]b4_args(
+                [int t],
+                b4_locations_if([const location_type& l]))[)
+    : super_type (]b4_locations_if([l])[)
+    , type (t)
+  {
+  }
+
+  ]b4_parser_class_name[::symbol_type::symbol_type (]b4_args(
+                 [int t],
+                 [const semantic_type& v],
+                 b4_locations_if([const location_type& l]))[)
+    : super_type (v]b4_locations_if([, l])[)
+    , type (t)
+  {
+  }
+
+  int
+  ]b4_parser_class_name[::symbol_type::type_get_ () const
+  {
+    return type;
+  }
+
+]b4_symbol_constructor_definitions[
+
+  // stack_symbol_type.
+  ]b4_parser_class_name[::stack_symbol_type::stack_symbol_type ()
+    : super_type ()
+    , state ()
+  {
+  }
+
+  ]b4_parser_class_name[::stack_symbol_type::stack_symbol_type (]b4_args(
+                 [state_type s],
+                 [const semantic_type& v],
+                 b4_locations_if([const location_type& l]))[)
+    : super_type (v]b4_locations_if([, l])[)
+    , state (s)
+  {
+  }
+
+  int
+  ]b4_parser_class_name[::stack_symbol_type::type_get_ () const
+  {
+    return yystos_[state];
+  }
+
+
+  template <typename Exact>
+  void
+  ]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.
+    switch (yytype)
+      {
 ]m4_map([b4_symbol_actions], m4_defn([b4_symbol_destructors]))[
-      default:
-        break;
-    }
-}
-
-void
-yy::]b4_parser_class_name[::pop (unsigned int n)
-{
-  state_stack_.pop (n);
-  semantic_stack_.pop (n);
-  location_stack_.pop (n);
-}
-
-int
-yy::]b4_parser_class_name[::parse ()
-{
-  nerrs_ = 0;
-  errstatus_ = 0;
-
-  /* Initialize the stacks.  The initial state will be pushed in
-     yynewstate, since the latter expects the semantical and the
-     location values to have been already stored, initialize these
-     stacks with a primary value.  */
-  state_stack_ = StateStack (0);
-  semantic_stack_ = SemanticStack (1);
-  location_stack_ = LocationStack (1);
-
-  /* Start.  */
-  state_ = 0;
-  looka_ = empty_;
-#if YYLSP_NEEDED
-  location = initlocation_;
-#endif
-  YYCDEBUG << "Starting parse" << std::endl;
+       default:
+         break;
+      }]b4_variant_if([
 
-  /* New state.  */
-yynewstate:
-  state_stack_.push (state_);
-  YYCDEBUG << "Entering state " << state_ << std::endl;
-  goto yybackup;
+    // Type destructor.
+  b4_symbol_variant([[yytype]], [[yysym.value]], [[template destroy]])])[
+  }
 
-  /* Backup.  */
-yybackup:
+#if YYDEBUG
+  template <typename Exact>
+  void
+  ]b4_parser_class_name[::yy_print_ (std::ostream& yyo,
+                                     const symbol_base_type<Exact>& yysym) const
+  {
+    int yytype = yysym.type_get ();
+    yyo << (yytype < yyntokens_ ? "token" : "nterm")
+        << ' ' << yytname_[yytype] << " ("]b4_locations_if([
+        << yysym.location << ": "])[;
+    switch (yytype)
+      {
+]m4_map([b4_symbol_actions], m4_defn([b4_symbol_printers]))[
+       default:
+         break;
+      }
+    yyo << ')';
+  }
+#endif
 
-  /* Try to take a decision without look-ahead.  */
-  n_ = pact_[state_];
-  if (n_ == pact_ninf_)
-    goto yydefault;
+  void
+  ]b4_parser_class_name[::yypush_ (const char* m, state_type s,
+                                   symbol_type& sym)
+  {
+    if (m)
+      YY_SYMBOL_PRINT (m, sym);
+]b4_variant_if(
+[[    yystack_.push (stack_symbol_type (]b4_args(
+                    [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(
+                      [s],
+                      [sym.value],
+                      b4_locations_if([sym.location]))[));]])[
+  }
 
-  /* Read a look-ahead token.  */
-  if (looka_ == empty_)
-    {
-      YYCDEBUG << "Reading a token: ";
-      lex_ ();
-    }
+  void
+  ]b4_parser_class_name[::yypush_ (const char* m, stack_symbol_type& s)
+  {
+    if (m)
+      YY_SYMBOL_PRINT (m, s);
+]b4_variant_if(
+[[    yystack_.push (stack_symbol_type (]b4_args(
+                       [s.state],
+                       [semantic_type()],
+                       b4_locations_if([s.location]))[));
+    ]b4_symbol_variant([[yystos_[s.state]]], [[yystack_[0].value]],
+                       [build], [s.value])],
+[    yystack_.push (s);])[
+  }
 
-  /* Convert token to internal form.  */
-  if (looka_ <= eof_)
-    {
-      looka_ = ilooka_ = eof_;
-      YYCDEBUG << "Now at end of input." << std::endl;
-    }
-  else
-    {
-      ilooka_ = translate_ (looka_);
-      YY_SYMBOL_PRINT ("Next token is", ilooka_, &value, &location);
-    }
+  void
+  ]b4_parser_class_name[::yypop_ (unsigned int n)
+  {
+    yystack_.pop (n);
+  }
 
-  /* If the proper action on seeing token ILOOKA_ is to reduce or to
-     detect an error, take that action.  */
-  n_ += ilooka_;
-  if (n_ < 0 || last_ < n_ || check_[n_] != ilooka_)
-    goto yydefault;
+#if YYDEBUG
+  std::ostream&
+  ]b4_parser_class_name[::debug_stream () const
+  {
+    return *yycdebug_;
+  }
 
-  /* Reduce or error.  */
-  n_ = table_[n_];
-  if (n_ < 0)
-    {
-      if (n_ == table_ninf_)
-       goto yyerrlab;
-      else
-       {
-         n_ = -n_;
-         goto yyreduce;
-       }
-    }
-  else if (n_ == 0)
-    goto yyerrlab;
-
-  /* Accept?  */
-  if (n_ == final_)
-    goto yyacceptlab;
-
-  /* Shift the look-ahead token.  */
-  YY_SYMBOL_PRINT ("Shifting", ilooka_, &value, &location);
-
-  /* Discard the token being shifted unless it is eof.  */
-  if (looka_ != eof_)
-    looka_ = empty_;
-
-  semantic_stack_.push (value);
-  location_stack_.push (location);
-
-  /* Count tokens shifted since error; after three, turn off error
-     status.  */
-  if (errstatus_)
-    --errstatus_;
-
-  state_ = n_;
-  goto yynewstate;
-
-/*-----------------------------------------------------------.
-| yydefault -- do the default action for the current state.  |
-`-----------------------------------------------------------*/
-yydefault:
-  n_ = defact_[state_];
-  if (n_ == 0)
-    goto yyerrlab;
-  goto yyreduce;
-
-/*-----------------------------.
-| yyreduce -- Do a reduction.  |
-`-----------------------------*/
-yyreduce:
-  len_ = r2_[n_];
-  /* If LEN_ is nonzero, implement the default value of the action:
-     `$$ = $1'.  Otherwise, use the top of the stack.
-
-     Otherwise, the following line sets YYVAL to garbage.
-     This behavior is undocumented and Bison
-     users should not rely upon it.  */
-  if (len_)
-    {
-      yyval = semantic_stack_[len_ - 1];
-      yyloc = location_stack_[len_ - 1];
-    }
-  else
-    {
-      yyval = semantic_stack_[0];
-      yyloc = location_stack_[0];
-    }
+  void
+  ]b4_parser_class_name[::set_debug_stream (std::ostream& o)
+  {
+    yycdebug_ = &o;
+  }
 
-  if (len_)
-    {
-      Slice< LocationType, LocationStack > slice (location_stack_, len_);
-      YYLLOC_DEFAULT (yyloc, slice, len_);
-    }
-  YY_REDUCE_PRINT (n_);
-  switch (n_)
-    {
-      ]b4_actions[
-    }
 
-]/* Line __line__ of lalr1.cc.  */
-b4_syncline([@oline@], [@ofile@])[
+  ]b4_parser_class_name[::debug_level_type
+  ]b4_parser_class_name[::debug_level () const
+  {
+    return yydebug_;
+  }
 
-  pop (len_);
+  void
+  ]b4_parser_class_name[::set_debug_level (debug_level_type l)
+  {
+    yydebug_ = l;
+  }
+#endif
 
-  YY_STACK_PRINT ();
+  int
+  ]b4_parser_class_name[::parse ()
+  {
+    /// Whether yyla contains a lookahead.
+    bool yyempty = true;
 
-  semantic_stack_.push (yyval);
-  location_stack_.push (yyloc);
+    /* State.  */
+    int yyn;
+    int yylen = 0;
+    int yystate = 0;
 
-  /* Shift the result of the reduction.  */
-  n_ = r1_[n_];
-  state_ = pgoto_[n_ - ntokens_] + state_stack_[0];
-  if (0 <= state_ && state_ <= last_ && check_[state_] == state_stack_[0])
-    state_ = table_[state_];
-  else
-    state_ = defgoto_[n_ - ntokens_];
-  goto yynewstate;
+    /* Error handling.  */
+    int yynerrs_ = 0;
+    int yyerrstatus_ = 0;
 
-/*------------------------------------.
-| yyerrlab -- here on detecting error |
-`------------------------------------*/
-yyerrlab:
-  /* If not already recovering from an error, report this error.  */
-  report_syntax_error_ ();
+    /// The lookahead symbol.
+    symbol_type yyla;]b4_locations_if([[
 
-  error_range_[0] = location;
-  if (errstatus_ == 3)
+    /// The locations where the error started and ended.
+    stack_symbol_type yyerror_range[2];]])[
+
+    /// $$ and @@$.
+    stack_symbol_type yylhs;
+
+    /// The return value of parse().
+    int yyresult;
+
+    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
+    /* User initialization code.  */
+    b4_user_initial_action
+m4_popdef([b4_dollar_dollar])dnl
+m4_popdef([b4_at_dollar])])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);
+
+    // A new state was pushed on the stack.
+    // Invariant: yystate == yystack_[0].state, i.e.,
+    // yystate was just pushed onto the state stack.
+  yynewstate:
+    YYCDEBUG << "Entering state " << yystate << std::endl;
+
+    /* Accept?  */
+    if (yystate == yyfinal_)
+      goto yyacceptlab;
+
+    goto yybackup;
+
+    /* Backup.  */
+  yybackup:
+
+    /* Try to take a decision without lookahead.  */
+    yyn = yypact_[yystate];
+    if (yyn == yypact_ninf_)
+      goto yydefault;
+
+    /* Read a lookahead token.  */
+    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
+b4_locations_if([, [[location*], [&yyla.location]]])dnl
+m4_ifdef([b4_lex_param], [, ]b4_lex_param)));])[
+        yyempty = false;
+      }
+    YY_SYMBOL_PRINT ("Next token is", yyla);
+
+    /* If the proper action on seeing token YYLA.TYPE is to reduce or
+       to detect an error, take that action.  */
+    yyn += yyla.type;
+    if (yyn < 0 || yylast_ < yyn || yycheck_[yyn] != yyla.type)
+      goto yydefault;
+
+    /* Reduce or error.  */
+    yyn = yytable_[yyn];
+    if (yyn <= 0)
+      {
+       if (yyn == 0 || yyn == yytable_ninf_)
+         goto yyerrlab;
+       yyn = -yyn;
+       goto yyreduce;
+      }
+
+    /* Discard the token being shifted.  */
+    yyempty = true;
+
+    /* Count tokens shifted since error; after three, turn off error
+       status.  */
+    if (yyerrstatus_)
+      --yyerrstatus_;
+
+    /* Shift the lookahead token.  */
+    yystate = yyn;
+    yypush_ ("Shifting", yystate, yyla);
+    goto yynewstate;
+
+  /*-----------------------------------------------------------.
+  | yydefault -- do the default action for the current state.  |
+  `-----------------------------------------------------------*/
+  yydefault:
+    yyn = yydefact_[yystate];
+    if (yyn == 0)
+      goto yyerrlab;
+    goto yyreduce;
+
+  /*-----------------------------.
+  | yyreduce -- Do a reduction.  |
+  `-----------------------------*/
+  yyreduce:
+    yylen = yyr2_[yyn];]b4_variant_if([
+    /* Variants are always initialized to an empty instance of the
+       correct type. The default $$=$1 rule is NOT applied when using
+       variants */
+    ]b4_symbol_variant([[yyr1_@{yyn@}]], [yylhs.value], [build])[],[
+    /* If YYLEN is nonzero, implement the default value of the action:
+       `$$ = $1'.  Otherwise, use the top of the stack.
+
+       Otherwise, the following line sets YYLHS.VALUE to garbage.
+       This behavior is undocumented and Bison
+       users should not rely upon it.  */
+    if (yylen)
+      yylhs.value = yystack_@{yylen - 1@}.value;
+    else
+      yylhs.value = yystack_@{0@}.value;])[
+]b4_locations_if([dnl
+[
+    // Compute the default @@$.
     {
-      /* If just tried and failed to reuse look-ahead token after an
-        error, discard it.  */
-
-      /* Return failure if at end of input.  */
-      if (looka_ <= eof_)
+      slice<stack_symbol_type, stack_type> slice (yystack_, yylen);
+      YYLLOC_DEFAULT (yylhs.location, slice, yylen);
+    }]])[
+
+    // Perform the reduction.
+    YY_REDUCE_PRINT (yyn);
+    switch (yyn)
+      {
+]b4_user_actions[
+       default:
+          break;
+      }
+    // Compute post-reduction state.
+    yyn = yyr1_[yyn];
+    yystate = yypgoto_[yyn - yyntokens_] + yystack_[yylen].state;
+    if (0 <= yystate && yystate <= yylast_
+       && yycheck_[yystate] == yystack_[yylen].state)
+      yystate = yytable_[yystate];
+    else
+      yystate = yydefgoto_[yyn - yyntokens_];
+    yylhs.state = yystate;
+    YY_SYMBOL_PRINT ("-> $$ =", yylhs);
+]b4_variant_if([[
+    // Destroy the lhs symbols.
+    for (int i = 0; i < yylen; ++i)
+      // Destroy a variant which value may have be swapped with
+      // yylhs.value.  The value of yylhs.value (hence maybe one of
+      // these lhs symbols) depends on what does the default
+      // contruction for this type.  In the case of pointers for
+      // instance, nothing is done, so the value is junk.  Therefore
+      // do not try to report the content in the debug trace, it's
+      // junk.  Hence yymsg = 0.  Besides, that keeps exactly the same
+      // traces as with the other Bison skeletons.
+      yy_destroy_ (0, yystack_[i]);]])[
+
+    yypop_ (yylen);
+    yylen = 0;
+    YY_STACK_PRINT ();
+
+    /* Shift the result of the reduction.  */
+    yypush_ (0, yylhs);
+    goto yynewstate;
+
+  /*------------------------------------.
+  | yyerrlab -- here on detecting error |
+  `------------------------------------*/
+  yyerrlab:
+    /* If not already recovering from an error, report this error.  */
+    if (!yyerrstatus_)
+      {
+       ++yynerrs_;
+       error (]b4_args(b4_locations_if([yyla.location]),
+                        [yysyntax_error_ (yystate, yyla.type)])[);
+      }
+
+]b4_locations_if([[
+    yyerror_range[0].location = yyla.location;]])[
+    if (yyerrstatus_ == 3)
+      {
+       /* If just tried and failed to reuse lookahead token after an
+           error, discard it.  */
+
+        /* Return failure if at end of input.  */
+        if (yyla.type == yyeof_)
+          YYABORT;
+        else
+          {
+            yy_destroy_ ("Error: discarding", yyla);
+            yyempty = true;
+         }
+      }
+
+    /* Else will try to reuse lookahead token after shifting the error
+       token.  */
+    goto yyerrlab1;
+
+
+  /*---------------------------------------------------.
+  | yyerrorlab -- error raised explicitly by YYERROR.  |
+  `---------------------------------------------------*/
+  yyerrorlab:
+
+    /* Pacify compilers like GCC when the user code never invokes
+       YYERROR and the label yyerrorlab therefore never appears in user
+       code.  */
+    if (false)
+      goto yyerrorlab;
+
+]b4_locations_if([[
+    yyerror_range[0].location = yystack_[yylen - 1].location;]])[
+    /* Do not reclaim the symbols of the rule which action triggered
+       this YYERROR.  */
+    yypop_ (yylen);
+    yylen = 0;
+    yystate = yystack_[0].state;
+    goto yyerrlab1;
+
+  /*-------------------------------------------------------------.
+  | yyerrlab1 -- common code for both syntax error and YYERROR.  |
+  `-------------------------------------------------------------*/
+  yyerrlab1:
+    yyerrstatus_ = 3;  /* Each real token shifted decrements this.  */
+    {
+      stack_symbol_type error_token;
+      for (;;)
         {
-          /* If at end of input, pop the error token,
-            then the rest of the stack, then return failure.  */
-         if (looka_ == eof_)
-            for (;;)
-              {
-                 error_range_[0] = location_stack_[0];
-                 pop ();
-                if (state_stack_.height () == 1)
-                  YYABORT;
-                 destruct_ ("Error: popping",
-                            stos_[state_stack_[0]],
-                            &semantic_stack_[0],
-                            &location_stack_[0]);
-              }
+          yyn = yypact_[yystate];
+          if (yyn != yypact_ninf_)
+            {
+              yyn += yyterror_;
+              if (0 <= yyn && yyn <= yylast_ && yycheck_[yyn] == yyterror_)
+                {
+                  yyn = yytable_[yyn];
+                  if (0 < yyn)
+                    break;
+                }
+            }
+
+          // Pop the current state because it cannot handle the error token.
+          if (yystack_.size () == 1)
+            YYABORT;
+]b4_locations_if([[
+          yyerror_range[0].location = yystack_[0].location;]])[
+          yy_destroy_ ("Error: popping", yystack_[0]);
+          yypop_ ();
+          yystate = yystack_[0].state;
+          YY_STACK_PRINT ();
         }
-      else
+]b4_locations_if([[
+      yyerror_range[1].location = yyla.location;
+      YYLLOC_DEFAULT (error_token.location, (yyerror_range - 1), 2);]])[
+
+      /* Shift the error token.  */
+      error_token.state = yystate = yyn;
+      yypush_ ("Shifting", error_token);
+    }
+    goto yynewstate;
+
+    /* Accept.  */
+  yyacceptlab:
+    yyresult = 0;
+    goto yyreturn;
+
+    /* Abort.  */
+  yyabortlab:
+    yyresult = 1;
+    goto yyreturn;
+
+  yyreturn:
+    if (!yyempty)
+      yy_destroy_ ("Cleanup: discarding lookahead", yyla);
+
+    /* Do not reclaim the symbols of the rule which action triggered
+       this YYABORT or YYACCEPT.  */
+    yypop_ (yylen);
+    while (yystack_.size () != 1)
+      {
+       yy_destroy_ ("Cleanup: popping", yystack_[0]);
+       yypop_ ();
+      }
+
+    return yyresult;
+  }
+
+  // Generate an error message.
+  std::string
+  ]b4_parser_class_name[::yysyntax_error_ (]dnl
+b4_error_verbose_if([int yystate, int yytoken],
+                    [int, int])[)
+  {
+    std::string yyres;]b4_error_verbose_if([[
+    int yyn = yypact_[yystate];
+    if (yypact_ninf_ < yyn && yyn <= yylast_)
+      {
+       /* Start YYX at -YYN if negative to avoid negative indexes in
+          YYCHECK.  */
+       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_;
+
+        // Number of "expected" tokens.
+       size_t yycount = 0;
+        // Its maximum.
+        enum { YYERROR_VERBOSE_ARGS_MAXIMUM = 5 };
+        // Arguments of yyformat.
+        char const *yyarg[YYERROR_VERBOSE_ARGS_MAXIMUM];
+        yyarg[yycount++] = yytname_[yytoken];
+       for (int yyx = yyxbegin; yyx < yyxend; ++yyx)
+         if (yycheck_[yyx + yyn] == yyx && yyx != yyterror_)
+          {
+            if (yycount == YYERROR_VERBOSE_ARGS_MAXIMUM)
+            {
+              yycount = 1;
+              break;
+            }
+            else
+              yyarg[yycount++] = yytname_[yyx];
+          }
+
+        char const* yyformat = 0;
+        switch (yycount)
         {
-          destruct_ ("Error: discarding", ilooka_, &value, &location);
-          looka_ = empty_;
+#define YYCASE_(N, S)                           \
+          case N:                               \
+            yyformat = S;                       \
+          break
+          YYCASE_(1, YY_("syntax error, unexpected %s"));
+          YYCASE_(2, YY_("syntax error, unexpected %s, expecting %s"));
+          YYCASE_(3, YY_("syntax error, unexpected %s, expecting %s or %s"));
+          YYCASE_(4, YY_("syntax error, unexpected %s, expecting %s or %s or %s"));
+          YYCASE_(5, YY_("syntax error, unexpected %s, expecting %s or %s or %s or %s"));
+#undef YYCASE_
         }
-    }
+        // Argument number.
+        size_t yyi = 0;
+        for (char const* yyp = yyformat; *yyp; ++yyp)
+          if (yyp[0] == '%' && yyp[1] == 's' && yyi < yycount)
+          {
+            yyres += yytnamerr_ (yyarg[yyi++]);
+            ++yyp;
+          }
+          else
+            yyres += *yyp;
+      }
+    else
+  ]])dnl
+[    yyres = YY_("syntax error");
+    return yyres;
+  }
 
-  /* Else will try to reuse look-ahead token after shifting the error
-     token.  */
-  goto yyerrlab1;
 
+  /* YYPACT[STATE-NUM] -- Index in YYTABLE of the portion describing
+     STATE-NUM.  */
+  const ]b4_int_type(b4_pact_ninf, b4_pact_ninf) b4_parser_class_name::yypact_ninf_ = b4_pact_ninf[;
+  ]b4_table_define([pact], [b4_pact])[;
 
-/*---------------------------------------------------.
-| yyerrorlab -- error raised explicitly by YYERROR.  |
-`---------------------------------------------------*/
-yyerrorlab:
+  /* YYDEFACT[S] -- default rule to reduce with in state S when YYTABLE
+     doesn't specify something else to do.  Zero means the default is an
+     error.  */
+  ]b4_table_define([defact], [b4_defact])[;
 
-#ifdef __GNUC__
-  /* Pacify GCC when the user code never invokes YYERROR and the label
-     yyerrorlab therefore never appears in user code.  */
-  if (0)
-     goto yyerrorlab;
-#endif
+  /* YYPGOTO[NTERM-NUM].  */
+  ]b4_table_define([pgoto], [b4_pgoto])[;
 
-  error_range_[0] = location_stack_[len_ - 1];
-  pop (len_);
-  state_ = state_stack_[0];
-  goto yyerrlab1;
+  /* YYDEFGOTO[NTERM-NUM].  */
+  ]b4_table_define([defgoto], [b4_defgoto])[;
 
-/*-------------------------------------------------------------.
-| yyerrlab1 -- common code for both syntax error and YYERROR.  |
-`-------------------------------------------------------------*/
-yyerrlab1:
-  errstatus_ = 3;      /* Each real token shifted decrements this.  */
+  /* YYTABLE[YYPACT[STATE-NUM]].  What to do in state STATE-NUM.  If
+     positive, shift that token.  If negative, reduce the rule which
+     number is the opposite.  If zero, do what YYDEFACT says.  */
+  const ]b4_int_type(b4_table_ninf, b4_table_ninf) b4_parser_class_name::yytable_ninf_ = b4_table_ninf[;
+  ]b4_table_define([table], [b4_table])[;
 
-  for (;;)
-    {
-      n_ = pact_[state_];
-      if (n_ != pact_ninf_)
-       {
-         n_ += terror_;
-         if (0 <= n_ && n_ <= last_ && check_[n_] == terror_)
-           {
-             n_ = table_[n_];
-             if (0 < n_)
-               break;
-           }
-       }
-
-      /* Pop the current state because it cannot handle the error token.  */
-      if (state_stack_.height () == 1)
-       YYABORT;
-
-      error_range_[0] = location_stack_[0];
-      destruct_ ("Error: popping",
-                 stos_[state_], &semantic_stack_[0], &location_stack_[0]);
-      pop ();
-      state_ = state_stack_[0];
-      YY_STACK_PRINT ();
-    }
+  /* YYCHECK.  */
+  ]b4_table_define([check], [b4_check])[;
 
-  if (n_ == final_)
-    goto yyacceptlab;
-
-  error_range_[1] = location;
-  // Using LOCATION is tempting, but would change the location of
-  // the look-ahead.  YYLOC is available though.
-  YYLLOC_DEFAULT (yyloc, error_range_ - 1, 2);
-  semantic_stack_.push (value);
-  location_stack_.push (yyloc);
-
-  /* Shift the error token. */
-  YY_SYMBOL_PRINT ("Shifting", stos_[n_],
-                  &semantic_stack_[0], &location_stack_[0]);
-
-  state_ = n_;
-  goto yynewstate;
-
-  /* Accept.  */
-yyacceptlab:
-  return 0;
-
-  /* Abort.  */
-yyabortlab:
-  /* Free the lookahead. */
-  destruct_ ("Error: discarding lookahead", ilooka_, &value, &location);
-  looka_ = empty_;
-  return 1;
-}
-
-void
-yy::]b4_parser_class_name[::lex_ ()
-{
-#if YYLSP_NEEDED
-  looka_ = yylex (&value, &location);
-#else
-  looka_ = yylex (&value);
-#endif
-}
-
-/** Generate an error message, and invoke yyerror. */
-void
-yy::]b4_parser_class_name[::report_syntax_error_ ()
-{
-  /* If not already recovering from an error, report this error.  */
-  if (!errstatus_)
-    {
-      ++nerrs_;
-
-#if YYERROR_VERBOSE
-      n_ = pact_[state_];
-      if (pact_ninf_ < n_ && n_ < last_)
-       {
-         message = "syntax error, unexpected ";
-         message += name_[ilooka_];
-         {
-           int count = 0;
-           for (int x = (n_ < 0 ? -n_ : 0); x < ntokens_ + nnts_; ++x)
-             if (check_[x + n_] == x && x != terror_)
-               ++count;
-           if (count < 5)
-             {
-               count = 0;
-               for (int x = (n_ < 0 ? -n_ : 0); x < ntokens_ + nnts_; ++x)
-                 if (check_[x + n_] == x && x != terror_)
-                   {
-                     message += (!count++) ? ", expecting " : " or ";
-                     message += name_[x];
-                   }
-             }
-         }
-       }
-      else
-#endif
-       message = "syntax error";
-      error_ ();
-    }
-}
-
-
-/* YYPACT[STATE-NUM] -- Index in YYTABLE of the portion describing
-   STATE-NUM.  */
-const ]b4_int_type(b4_pact_ninf, b4_pact_ninf) yy::b4_parser_class_name::pact_ninf_ = b4_pact_ninf[;
-const ]b4_int_type_for([b4_pact])[
-yy::]b4_parser_class_name[::pact_[] =
-{
-  ]b4_pact[
-};
-
-/* YYDEFACT[S] -- default rule to reduce with in state S when YYTABLE
-   doesn't specify something else to do.  Zero means the default is an
-   error.  */
-const ]b4_int_type_for([b4_defact])[
-yy::]b4_parser_class_name[::defact_[] =
-{
-  ]b4_defact[
-};
-
-/* YYPGOTO[NTERM-NUM].  */
-const ]b4_int_type_for([b4_pgoto])[
-yy::]b4_parser_class_name[::pgoto_[] =
-{
-  ]b4_pgoto[
-};
-
-/* YYDEFGOTO[NTERM-NUM].  */
-const ]b4_int_type_for([b4_defgoto])[
-yy::]b4_parser_class_name[::defgoto_[] =
-{
-  ]b4_defgoto[
-};
-
-/* YYTABLE[YYPACT[STATE-NUM]].  What to do in state STATE-NUM.  If
-   positive, shift that token.  If negative, reduce the rule which
-   number is the opposite.  If zero, do what YYDEFACT says.  */
-const ]b4_int_type(b4_table_ninf, b4_table_ninf) yy::b4_parser_class_name::table_ninf_ = b4_table_ninf[;
-const ]b4_int_type_for([b4_table])[
-yy::]b4_parser_class_name[::table_[] =
-{
-  ]b4_table[
-};
-
-/* YYCHECK.  */
-const ]b4_int_type_for([b4_check])[
-yy::]b4_parser_class_name[::check_[] =
-{
-  ]b4_check[
-};
-
-/* STOS_[STATE-NUM] -- The (internal number of the) accessing
-   symbol of state STATE-NUM.  */
-const ]b4_int_type_for([b4_stos])[
-yy::]b4_parser_class_name[::stos_[] =
-{
-  ]b4_stos[
-};
+  /* STOS_[STATE-NUM] -- The (internal number of the) accessing
+     symbol of state STATE-NUM.  */
+  ]b4_table_define([stos], [b4_stos])[;
 
 #if YYDEBUG
-/* TOKEN_NUMBER_[YYLEX-NUM] -- Internal token number corresponding
-   to YYLEX-NUM.  */
-const ]b4_int_type_for([b4_toknum])[
-yy::]b4_parser_class_name[::token_number_[] =
-{
-  ]b4_toknum[
-};
+  /* TOKEN_NUMBER_[YYLEX-NUM] -- Internal symbol number corresponding
+     to YYLEX-NUM.  */
+  ]b4_table_define([token_number], [b4_toknum])[;
 #endif
 
-/* YYR1[YYN] -- Symbol number of symbol that rule YYN derives.  */
-const ]b4_int_type_for([b4_r1])[
-yy::]b4_parser_class_name[::r1_[] =
-{
-  ]b4_r1[
-};
-
-/* YYR2[YYN] -- Number of symbols composing right hand side of rule YYN.  */
-const ]b4_int_type_for([b4_r2])[
-yy::]b4_parser_class_name[::r2_[] =
-{
-  ]b4_r2[
-};
-
-#if YYDEBUG || YYERROR_VERBOSE
-/* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
-   First, the terminals, then, starting at NTOKENS_, nonterminals. */
-const char*
-const yy::]b4_parser_class_name[::name_[] =
-{
+  /* YYR1[YYN] -- Symbol number of symbol that rule YYN derives.  */
+  ]b4_table_define([r1], [b4_r1])[;
+
+  /* YYR2[YYN] -- Number of symbols composing right hand side of rule YYN.  */
+  ]b4_table_define([r2], [b4_r2])[;
+
+#if YYDEBUG || YYERROR_VERBOSE || YYTOKEN_TABLE
+  /* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
+     First, the terminals, then, starting at \a yyntokens_, nonterminals.  */
+  const char*
+  const ]b4_parser_class_name[::yytname_[] =
+  {
   ]b4_tname[
-};
+  };
 #endif
 
 #if YYDEBUG
-/* YYRHS -- A `-1'-separated list of the rules' RHS. */
-const yy::]b4_parser_class_name[::RhsNumberType
-yy::]b4_parser_class_name[::rhs_[] =
-{
-  ]b4_rhs[
-};
-
-/* YYPRHS[YYN] -- Index of the first RHS symbol of rule number YYN in
-   YYRHS.  */
-const ]b4_int_type_for([b4_prhs])[
-yy::]b4_parser_class_name[::prhs_[] =
-{
-  ]b4_prhs[
-};
-
-/* YYRLINE[YYN] -- source line where rule number YYN was defined.  */
-const ]b4_int_type_for([b4_rline])[
-yy::]b4_parser_class_name[::rline_[] =
-{
-  ]b4_rline[
-};
-
-/** Print the state stack from its BOTTOM up to its TOP (included).  */
-
-void
-yy::]b4_parser_class_name[::stack_print_ ()
-{
-  cdebug_ << "Stack now";
-  for (StateStack::const_iterator i = state_stack_.begin ();
-       i != state_stack_.end (); ++i)
-    cdebug_ << ' ' << *i;
-  cdebug_ << std::endl;
-}
-
-/** Report that the YYRULE is going to be reduced.  */
-
-void
-yy::]b4_parser_class_name[::reduce_print_ (int yyrule)
-{
-  unsigned int yylno = rline_[yyrule];
-  /* Print the symbols being reduced, and their result.  */
-  cdebug_ << "Reducing stack by rule " << n_ - 1 << " (line " << yylno << "), ";
-  for (]b4_int_type_for([b4_prhs])[ i = prhs_[n_];
-       0 <= rhs_[i]; ++i)
-    cdebug_ << name_[rhs_[i]] << ' ';
-  cdebug_ << "-> " << name_[r1_[n_]] << std::endl;
-}
-#endif // YYDEBUG
+  /* YYRLINE[YYN] -- Source line where rule number YYN was defined.  */
+  ]b4_table_define([rline], [b4_rline])[;
 
-/* YYTRANSLATE(YYLEX) -- Bison symbol number corresponding to YYLEX.  */
-yy::]b4_parser_class_name[::TokenNumberType
-yy::]b4_parser_class_name[::translate_ (int token)
-{
-  static
-  const TokenNumberType
-  translate_table[] =
+  // Print the state stack on the debug stream.
+  void
+  ]b4_parser_class_name[::yystack_print_ ()
   {
-    ]b4_translate[
-  };
-  if ((unsigned int) token <= user_token_number_max_)
-    return translate_table[token];
-  else
-    return undef_token_;
-}
-
-const int yy::]b4_parser_class_name[::eof_ = 0;
-const int yy::]b4_parser_class_name[::last_ = ]b4_last[;
-const int yy::]b4_parser_class_name[::nnts_ = ]b4_nterms_number[;
-const int yy::]b4_parser_class_name[::empty_ = -2;
-const int yy::]b4_parser_class_name[::final_ = ]b4_final_state_number[;
-const int yy::]b4_parser_class_name[::terror_ = 1;
-const int yy::]b4_parser_class_name[::errcode_ = 256;
-const int yy::]b4_parser_class_name[::ntokens_ = ]b4_tokens_number[;
-
-const unsigned int yy::]b4_parser_class_name[::user_token_number_max_ = ]b4_user_token_number_max[;
-const yy::]b4_parser_class_name[::TokenNumberType yy::]b4_parser_class_name[::undef_token_ = ]b4_undef_token_number[;
-
-]b4_epilogue
-dnl
-@output stack.hh
-b4_copyright([Stack handling for Bison C++ parsers], [2002, 2003, 2004])[
+    *yycdebug_ << "Stack now";
+    for (stack_type::const_iterator
+           i = yystack_.begin (),
+           i_end = yystack_.end ();
+        i != i_end; ++i)
+      *yycdebug_ << ' ' << i->state;
+    *yycdebug_ << std::endl;
+  }
+
+  // Report on the debug stream that the rule \a yyrule is going to be reduced.
+  void
+  ]b4_parser_class_name[::yy_reduce_print_ (int yyrule)
+  {
+    unsigned int yylno = yyrline_[yyrule];
+    int yynrhs = yyr2_[yyrule];
+    /* Print the symbols being reduced, and their result.  */
+    *yycdebug_ << "Reducing stack by rule " << yyrule - 1
+              << " (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
+
+]b4_yytranslate_definition[
+]b4_namespace_close[
+
+]b4_epilogue[]dnl
+@output(b4_dir_prefix[]stack.hh@)@
+b4_copyright([Stack handling for Bison parsers in C++])[
 
 #ifndef BISON_STACK_HH
 # define BISON_STACK_HH
 
 #include <deque>
 
-namespace yy
-{
-  template < class T, class S = std::deque< T > >
-  class Stack
+]b4_namespace_open[
+  template <class T, class S = std::deque<T> >
+  class stack
   {
   public:
 
@@ -963,11 +1636,11 @@ namespace yy
     typedef typename S::reverse_iterator iterator;
     typedef typename S::const_reverse_iterator const_iterator;
 
-    Stack () : seq_ ()
+    stack () : seq_ ()
     {
     }
 
-    Stack (unsigned int n) : seq_ (n)
+    stack (unsigned int n) : seq_ (n)
     {
     }
 
@@ -1001,26 +1674,27 @@ namespace yy
     }
 
     inline
-    unsigned int
-    height () const
+    typename S::size_type
+    size () const
     {
       return seq_.size ();
     }
 
     inline const_iterator begin () const { return seq_.rbegin (); }
-    inline const_iterator end () const { return seq_.rend (); }
+    inline const_iterator end ()   const { return seq_.rend ();   }
 
   private:
-
+    /// The wrapped container.
     S seq_;
   };
 
-  template < class T, class S = Stack< T > >
-  class Slice
+  /// Present a slice of the top of a stack.
+  template <class T, class S = stack<T> >
+  class slice
   {
   public:
 
-    Slice (const S& stack,
+    slice (const S& stack,
           unsigned int range) : stack_ (stack),
                                 range_ (range)
     {
@@ -1038,228 +1712,9 @@ namespace yy
     const S& stack_;
     unsigned int range_;
   };
-}
-
-#endif // not BISON_STACK_HH]
-dnl
-@output position.hh
-b4_copyright([Position class for Bison C++ parsers], [2002, 2003, 2004])[
-
-/**
- ** \file position.hh
- ** Define the Location class.
- */
-
-#ifndef BISON_POSITION_HH
-# define BISON_POSITION_HH
-
-# include <iostream>
-# include <string>
-
-namespace yy
-{
-  /** \brief Abstract a Position. */
-  class Position
-  {
-  public:
-    /** \brief Initial column number. */
-    static const unsigned int initial_column = 0;
-    /** \brief Initial line number. */
-    static const unsigned int initial_line = 1;
-
-    /** \name Ctor & dtor.
-     ** \{ */
-  public:
-    /** \brief Construct a Position. */
-    Position () :
-      filename (),
-      line (initial_line),
-      column (initial_column)
-    {
-    }
-    /** \} */
-
-
-    /** \name Line and Column related manipulators
-     ** \{ */
-  public:
-    /** \brief (line related) Advance to the COUNT next lines. */
-    inline void lines (int count = 1)
-    {
-      column = initial_column;
-      line += count;
-    }
-
-    /** \brief (column related) Advance to the COUNT next columns. */
-    inline void columns (int count = 1)
-    {
-      int leftmost = initial_column;
-      int current  = column;
-      if (leftmost <= current + count)
-       column += count;
-      else
-       column = initial_column;
-    }
-    /** \} */
-
-  public:
-    /** \brief File name to which this position refers. */
-    std::string filename;
-    /** \brief Current line number. */
-    unsigned int line;
-    /** \brief Current column number. */
-    unsigned int column;
-  };
-
-  /** \brief Add and assign a Position. */
-  inline const Position&
-  operator+= (Position& res, const int width)
-  {
-    res.columns (width);
-    return res;
-  }
-
-  /** \brief Add two Position objects. */
-  inline const Position
-  operator+ (const Position& begin, const int width)
-  {
-    Position res = begin;
-    return res += width;
-  }
-
-  /** \brief Add and assign a Position. */
-  inline const Position&
-  operator-= (Position& res, const int width)
-  {
-    return res += -width;
-  }
-
-  /** \brief Add two Position objects. */
-  inline const Position
-  operator- (const Position& begin, const int width)
-  {
-    return begin + -width;
-  }
-
-  /** \brief Intercept output stream redirection.
-   ** \param ostr the destination output stream
-   ** \param pos a reference to the Position to redirect
-   */
-  inline std::ostream&
-  operator<< (std::ostream& ostr, const Position& pos)
-  {
-    if (!pos.filename.empty ())
-      ostr << pos.filename << ':';
-    return ostr << pos.line << '.' << pos.column;
-  }
-
-}
-#endif // not BISON_POSITION_HH]
-@output location.hh
-b4_copyright([Location class for Bison C++ parsers], [2002, 2003, 2004])[
-
-/**
- ** \file location.hh
- ** Define the Location class.
- */
-
-#ifndef BISON_LOCATION_HH
-# define BISON_LOCATION_HH
-
-# include <iostream>
-# include <string>
-# include "position.hh"
-
-namespace yy
-{
-
-  /** \brief Abstract a Location. */
-  class Location
-  {
-    /** \name Ctor & dtor.
-     ** \{ */
-  public:
-    /** \brief Construct a Location. */
-    Location (void) :
-      begin (),
-      end ()
-    {
-    }
-    /** \} */
-
-
-    /** \name Line and Column related manipulators
-     ** \{ */
-  public:
-    /** \brief Reset initial location to final location. */
-    inline void step (void)
-    {
-      begin = end;
-    }
-
-    /** \brief Extend the current location to the COUNT next columns. */
-    inline void columns (unsigned int count = 1)
-    {
-      end += count;
-    }
-
-    /** \brief Extend the current location to the COUNT next lines. */
-    inline void lines (unsigned int count = 1)
-    {
-      end.lines (count);
-    }
-    /** \} */
-
-
-  public:
-    /** \brief Beginning of the located region. */
-    Position begin;
-    /** \brief End of the located region. */
-    Position end;
-  };
-
-  /** \brief Join two Location objects to create a Location. */
-  inline const Location operator+ (const Location& begin, const Location& end)
-  {
-    Location res = begin;
-    res.end = end.end;
-    return res;
-  }
-
-  /** \brief Add two Location objects */
-  inline const Location operator+ (const Location& begin, unsigned int width)
-  {
-    Location res = begin;
-    res.columns (width);
-    return res;
-  }
-
-  /** \brief Add and assign a Location */
-  inline Location &operator+= (Location& res, unsigned int width)
-  {
-    res.columns (width);
-    return res;
-  }
-
-  /** \brief Intercept output stream redirection.
-   ** \param ostr the destination output stream
-   ** \param loc a reference to the Location to redirect
-   **
-   ** Avoid duplicate information.
-   */
-  inline std::ostream& operator<< (std::ostream& ostr, const Location& loc)
-  {
-    Position last = loc.end - 1;
-    ostr << loc.begin;
-    if (loc.begin.filename != last.filename)
-      ostr << '-' << last;
-    else if (loc.begin.line != last.line)
-      ostr << '-' << last.line  << '.' << last.column;
-    else if (loc.begin.column != last.column)
-      ostr << '-' << last.column;
-    return ostr;
-  }
-
-}
+]b4_namespace_close[
 
-#endif // not BISON_LOCATION_HH]
+#endif // not BISON_STACK_HH[]dnl
+]
+m4_divert_pop(0)
+m4_popdef([b4_copyright_years])dnl