# C++ skeleton for Bison
-# Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007 Free Software Foundation,
-# Inc.
+# 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
m4_include(b4_pkgdatadir/[c++.m4])
+# 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_variant_if
+
+
+# b4_symbol_action_(SYMBOL-TAG, SYMBOL-NUM, SYMBOL-TYPENAME)
+# ----------------------------------------------------------
+# Invoke b4_dollar_dollar(SYMBOL_TYPENAME) for each symbol.
+m4_define([b4_symbol_action_],
+[m4_ifval($3,
+[ case $2: // $1
+ b4_dollar_dollar($@);
+ break;
+])])
+
+
+# b4_symbol_variant(YYTYPE, YYVAL, ACTION)
+# ----------------------------------------
+# 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>()])dnl
+ switch ($1)
+ {
+m4_map([b4_symbol_action_], m4_defn([b4_type_names]))
+ 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-TAG, SYMBOL-NUM, SYMBOL-TYPENAME)
+# -------------------------------------------------------
+# 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.
+# $3 is doubly-quoted, do not quote it again.
+m4_define([b4_char_sizeof],
+[m4_ifval($3,
+[
+ char _b4_char_sizeof_dummy@{sizeof($3)@}; // $1])dnl
+])
+
+
m4_define([b4_parser_class_name],
[b4_percent_define_get([[parser_class_name]])])
b4_defines_if(
[@output(b4_spec_defines_file@)
b4_copyright([Skeleton interface for Bison LALR(1) parsers in C++],
- [2002, 2003, 2004, 2005, 2006])
+ [2002, 2003, 2004, 2005, 2006, 2007, 2008])
dnl FIXME: This is wrong, we want computed header guards.
[
/* C++ LALR(1) parser skeleton written by Akim Demaille. */
]b4_namespace_open[
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
+ {
+ /// Instantiate a \a T in here.
+ template <typename T>
+ inline void
+ build()
+ {
+ new (buffer) T;
+ }
+
+ /// Destroy the stored \a T.
+ template <typename T>
+ inline void
+ destroy()
+ {
+ reinterpret_cast<T&>(buffer).~T();
+ }
+
+ /// Accessor to a built \a T.
+ template <typename T>
+ inline T&
+ as()
+ {
+ return reinterpret_cast<T&>(buffer);
+ }
+
+ /// Const accessor to a built \a T (for %printer).
+ template <typename T>
+ inline const T&
+ as() const
+ {
+ return reinterpret_cast<const T&>(buffer);
+ }
+
+ /// A buffer large enough to store any of the semantic values.
+ char buffer[S];
+ };
+]])[
]b4_namespace_close[
#include "location.hh"
class ]b4_parser_class_name[
{
public:
- /// Symbol semantic values.
#ifndef YYSTYPE
-]m4_ifdef([b4_stype],
+]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
+ {b4_user_stype
};],
[m4_if(b4_tag_seen_flag, 0,
[[ typedef int semantic_type;]],
-[[ typedef YYSTYPE semantic_type;]])])[
+[[ typedef YYSTYPE semantic_type;]])])])[
#else
typedef YYSTYPE semantic_type;
#endif
/// \returns 0 iff parsing succeeded.
virtual int parse ();
+#if YYDEBUG
/// The current debugging stream.
std::ostream& debug_stream () const;
/// Set the current debugging stream.
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.
])dnl
@output(b4_parser_file_name@)
b4_copyright([Skeleton implementation for Bison LALR(1) parsers in C++],
- [2002, 2003, 2004, 2005, 2006])
+ [2002, 2003, 2004, 2005, 2006, 2007, 2008])
b4_percent_code_get([[top]])[]dnl
m4_if(b4_prefix, [yy], [],
[
/* Discard the token being shifted. */
yychar = yyempty_;
-
yysemantic_stack_.push (yylval);
yylocation_stack_.push (yylloc);
| yyreduce -- Do a reduction. |
`-----------------------------*/
yyreduce:
- yylen = yyr2_[yyn];
+ yylen = yyr2_[yyn];]b4_variant_if([
+ /* Variants are always initialized to an empty instance of the
+ correct type. The default $$=$1 rule is NOT applied when using
+ variants */
+ ]b4_symbol_variant([[yyr1_@{yyn@}]], [yyval], [build])[],[
/* If YYLEN is nonzero, implement the default value of the action:
`$$ = $1'. Otherwise, use the top of the stack.
This behavior is undocumented and Bison
users should not rely upon it. */
if (yylen)
- yyval = yysemantic_stack_[yylen - 1];
+ yyval = yysemantic_stack_@{yylen - 1@};
else
- yyval = yysemantic_stack_[0];
+ yyval = yysemantic_stack_@{0@};])[
{
slice<location_type, location_stack_type> slice (yylocation_stack_, yylen);
switch (yyn)
{
]b4_user_actions[
- default: break;
+ default:
+ break;
}
YY_SYMBOL_PRINT ("-> $$ =", yyr1_[yyn], &yyval, &yyloc);
yypop_ (yylen);
yylen = 0;
YY_STACK_PRINT ();
-
yysemantic_stack_.push (yyval);
yylocation_stack_.push (yyloc);
/* Shift the error token. */
YY_SYMBOL_PRINT ("Shifting", yystos_[yyn],
- &yysemantic_stack_[0], &yylocation_stack_[0]);
+ &yysemantic_stack_[0], &yylocation_stack_[0]);
yystate = yyn;
goto yynewstate;
dnl
@output(b4_dir_prefix[]stack.hh@)
b4_copyright([Stack handling for Bison parsers in C++],
- [2002, 2003, 2004, 2005, 2006])[
+ [2002, 2003, 2004, 2005, 2006, 2007, 2008])[
#ifndef BISON_STACK_HH
# define BISON_STACK_HH
};
]b4_namespace_close[
-#endif // not BISON_STACK_HH]
+#endif // not BISON_STACK_HH[]dnl
+]
m4_divert_pop(0)
projects / bison.git / blobdiff