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Modern C++ (i.e., C++11 and later) introduced "move only" types: types such as std::unique_ptr<T> that can never be duplicated. They must never be copied (by assignments and constructors), they must be "moved". The implementation of lalr1.cc used to copy symbols (including their semantic values). This commit ensures that values are only moved in modern C++, yet remain compatible with C++98/C++03. Suggested by Frank Heckenbach, who provided a full implementation on top of C++17's std::variant. See http://lists.gnu.org/archive/html/bug-bison/2018-03/msg00002.html, and https://lists.gnu.org/archive/html/bison-patches/2018-04/msg00002.html. Symbols (terminal/non terminal) are handled by several functions that used to take const-refs, which resulted eventually in a copy pushed on the stack. With modern C++ (C++11 and later) the callers must use std::move, and the callees must take their arguments as rvalue refs (foo&&). In order to avoid duplicating these functions to support both legacy C++ and modern C++, let's introduce macros (YY_MOVE, YY_RVREF, etc.) that rely on copy-semantics for C++98/03, and move-semantics for modern C++. That's easy for inner types, when the parser's functions pass arguments to each other. Functions facing the user (make_NUMBER, make_STRING, etc.) should support both rvalue-refs (for instance to support move-only types: make_INT (std::make_unique<int> (1))), and lvalue-refs (so that we can pass a variable: make_INT (my_int)). To avoid the multiplication of the signatures (there is also the location), let's take the argument by value. See: https://lists.gnu.org/archive/html/bison-patches/2018-09/msg00024.html. * data/c++.m4 (b4_cxx_portability): New. (basic_symbol): In C++11, replace copy-ctors with move-ctors. In C++11, replace copies with moves. * data/lalr1.cc (stack_symbol_type, yypush_): Likewise. Use YY_MOVE to avoid useless copies. * data/variant.hh (variant): Support move-semantics. (make_SYMBOL): In C++11, in order to support both read-only lvalues, and rvalues, take the argument as a copy. * data/stack.hh (yypush_): Use rvalue-refs in C++11. * tests/c++.at: Use move semantics. * tests/headers.at: Adjust to the new macros (YY_MOVE, etc.). * configure.ac (CXX98_CXXFLAGS, CXX11_CXXFLAGS, CXX14_CXXFLAGS) (CXX17_CXXFLAGS, ENABLE_CXX11): New. * tests/atlocal.in: Receive them. * examples/variant.yy: Don't define things in std. * examples/variant-11.test, examples/variant-11.yy: New. Check the support of move-only types. * examples/README, examples/local.mk: Adjust.
351 lines
7.6 KiB
Plaintext
351 lines
7.6 KiB
Plaintext
# Bison Parser Headers. -*- Autotest -*-
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# Copyright (C) 2001-2002, 2006-2007, 2009-2015, 2018 Free Software
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# Foundation, Inc.
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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AT_BANNER([[Parser Headers.]])
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## --------------------- ##
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## Invalid CPP headers. ##
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## --------------------- ##
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# AT_TEST_CPP_GUARD_H(BASE-NAME, [DIRECTIVES])
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# --------------------------------------------
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# FIXME: Much of this can be covered by calc.at.
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m4_define([AT_TEST_CPP_GUARD_H],
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[AT_SETUP([Invalid CPP guards: $2 --defines=$1.h])
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AT_BISON_OPTION_PUSHDEFS([$2])
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# Possibly create inner directories.
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dirname=`AS_DIRNAME([$1])`
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AS_MKDIR_P([$dirname])
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AT_DATA_GRAMMAR([$1.y],
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[$2
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%{
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#include <$1.h>
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]AT_YYERROR_DECLARE_EXTERN[
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]AT_YYLEX_DECLARE_EXTERN[
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%}
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%%
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dummy: /* empty */;
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%%
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#include <$1.h>
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])
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AT_BISON_CHECK([--defines=$1.h --output=$1.c $1.y])
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AT_COMPILE([$1.o], [-I. -c $1.c])
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AT_BISON_OPTION_POPDEFS
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AT_CLEANUP
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])
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AT_TEST_CPP_GUARD_H([input/input])
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AT_TEST_CPP_GUARD_H([9foo])
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AT_TEST_CPP_GUARD_H([input/input], [%glr-parser])
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AT_TEST_CPP_GUARD_H([9foo], [%glr-parser])
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## ---------------- ##
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## export YYLTYPE. ##
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## ---------------- ##
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AT_SETUP([export YYLTYPE])
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AT_BISON_OPTION_PUSHDEFS([%name-prefix "my_"])
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AT_DATA_GRAMMAR([input.y],
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[[%locations
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%name-prefix "my_"
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%{
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#include <stdio.h>
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#include <stdlib.h>
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]AT_YYERROR_DEFINE[
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]AT_YYLEX_DEFINE[
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%}
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%%
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exp: /* empty */;
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]])
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AT_BISON_CHECK([--defines -o input.c input.y])
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# YYLTYPE should be defined, and MY_LLOC declared.
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AT_DATA([caller.c],
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[[#include "input.h"
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YYLTYPE *my_llocp = &my_lloc;
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int my_parse (void);
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]AT_MAIN_DEFINE[
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]])
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# Link and execute, just to make sure everything is fine (and in
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# particular, that MY_LLOC is indeed defined somewhere).
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AT_COMPILE([caller.o])
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AT_COMPILE([input.o])
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AT_COMPILE([caller], [caller.o input.o])
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AT_PARSER_CHECK([./caller])
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AT_BISON_OPTION_POPDEFS
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AT_CLEANUP
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## -------------- ##
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## Sane headers. ##
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## -------------- ##
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# AT_TEST([DIRECTIVES], [COMPILER-FLAGS])
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# ---------------------------------------
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# Check that headers are self-contained and protected againt multiple
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# inclusions.
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m4_pushdef([AT_TEST],
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[AT_SETUP([Sane headers: $1])
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AT_BISON_OPTION_PUSHDEFS([$1])
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AT_DATA_GRAMMAR([input.y],
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[[$1
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%error-verbose
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]AT_VARIANT_IF([], [%union {int integer;}])[
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%code {
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]AT_PUSH_IF([[
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#if defined __GNUC__ && 7 == __GNUC__
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# pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
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#endif
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]])[
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]AT_YYERROR_DECLARE[
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]AT_YYLEX_DECLARE[
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}
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%%
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exp:
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'x' { printf ("x\n"); }
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;
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%%
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]AT_YYERROR_DEFINE[
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]AT_YYLEX_DEFINE(["x"])[
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]])
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AT_BISON_CHECK([-d -o input.AT_SKEL_CC_IF([cc], [c]) input.y])
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AT_LANG_COMPILE([input.o])
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AT_DATA([main.cc],
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[AT_DATA_SOURCE_PROLOGUE
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AT_MAIN_DEFINE
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])
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# Check that the headers are self-contained, and protected against
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# multiple inclusions. While at it, check they are sane for C++.
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for h in *.AT_SKEL_CC_IF([hh], [h])
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do
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# No shell expansion with AT_DATA.
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cat >$h.AT_SKEL_CC_IF([cc], [c]) <<EOF
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AT_DATA_SOURCE_PROLOGUE
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#include "$h"
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#include "$h"
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EOF
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AT_LANG_COMPILE([$h.o])
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done
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AT_BISON_OPTION_POPDEFS
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AT_CLEANUP
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])# AT_TEST
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AT_TEST([])
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AT_TEST([%locations %debug])
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AT_TEST([%glr-parser])
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AT_TEST([%locations %debug %glr-parser])
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AT_TEST([%define api.pure])
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AT_TEST([%define api.push-pull both])
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AT_TEST([%define api.pure %define api.push-pull both])
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AT_TEST([%language "c++"])
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AT_TEST([%locations %debug %language "c++"])
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AT_TEST([%language "c++" %define api.value.type variant %define parse.assert])
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AT_TEST([%locations %language "c++" %glr-parser])
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## ----------------- ##
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## Several parsers. ##
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## ----------------- ##
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AT_SETUP([Several parsers])
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# AT_TEST([PREFIX], [DIRECTIVES])
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# -------------------------------
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# Generate and compile to *.o. Make sure there is no (allowed) YY*
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# nor yy* identifiers in the header after applying api.prefix. Check
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# that headers can be compiled by a C++ compiler.
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m4_pushdef([AT_TEST],
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[AT_BISON_OPTION_PUSHDEFS([%define api.prefix {$1_} $2])
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AT_DATA_GRAMMAR([$1.y],
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[[%define api.prefix {$1_}
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$2
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%error-verbose
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%union
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{
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int integer;
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}
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%{
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]AT_PUSH_IF([[
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#if defined __GNUC__ && 7 == __GNUC__
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# pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
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#endif
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]])[
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]AT_YYERROR_DECLARE[
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]AT_YYLEX_DECLARE[
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%}
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%%
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exp:
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'x' '1' { printf ("x1\n"); }
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| 'x' '2' { printf ("x2\n"); }
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| 'x' '3' { printf ("x3\n"); }
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| 'x' '4' { printf ("x4\n"); }
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| 'x' '5' { printf ("x5\n"); }
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| 'x' '6' { printf ("x6\n"); }
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| 'x' '7' { printf ("x7\n"); }
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| 'x' '8' { printf ("x8\n"); }
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;
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%%
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]AT_YYERROR_DEFINE[
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]AT_YYLEX_DEFINE(["$1"])[
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]])
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AT_BISON_CHECK([-d -o $1.AT_SKEL_CC_IF([cc], [c]) $1.y])
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AT_LANG_COMPILE([$1.o])
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AT_CHECK([[echo "$1" >>expout]])
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AT_BISON_OPTION_POPDEFS
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])# AT_TEST
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AT_DATA([main.cc],
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[AT_DATA_SOURCE_PROLOGUE
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[// If we are compiling with CC=$CXX, then do not load the C headers
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// inside extern "C", since they were _not_ compiled this way.
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#if ! CC_IS_CXX
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extern "C"
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{
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#endif
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#include "x1.h"
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#include "x2.h"
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#include "x3.h"
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#include "x4.h"
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#include "x6.h"
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#include "x7.h"
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#include "x8.h"
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#if ! CC_IS_CXX
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}
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#endif
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#include "x5.hh"
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//#include "x6.hh"
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#define RUN(S) \
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do { \
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int res = S; \
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if (res) \
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std::cerr << #S": " << res << '\n'; \
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} while (false)
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int
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main (void)
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{
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RUN(x1_parse());
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RUN(x2_parse());
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RUN(x3_parse());
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RUN(x4_parse());
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x5_::parser p5;
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RUN(p5.parse());
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RUN(x6_parse());
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RUN(x7_parse());
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RUN(x8_parse());
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// x6_::parser p6;
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// RUN(p6.parse());
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return 0;
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}
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]])# main.cc
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AT_TEST([x1], [])
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AT_TEST([x2], [%locations %debug])
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AT_TEST([x3], [%glr-parser])
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AT_TEST([x4], [%locations %debug %glr-parser])
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AT_TEST([x5], [%locations %debug %language "c++"])
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AT_TEST([x6], [%define api.pure])
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AT_TEST([x7], [%define api.push-pull both])
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AT_TEST([x8], [%define api.pure %define api.push-pull both])
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#AT_TEST([x5], [%locations %language "c++" %glr-parser])
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# Check that api.prefix works properly:
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#
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# - no 'yy' left.
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# C++ output relies on namespaces and still uses yy a lot.
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#
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# - no 'YY' left.
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# Ignore comments, YYChar (template parameter), YYPUSH_MORE(_DEFINED)?
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# (constant definition), YY_\w+_INCLUDED (header guards).
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# YYDEBUG (not renamed) can be read, but not changed.
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AT_CHECK([[$PERL -n -0777 -e '
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s{/\*.*?\*/}{}gs;
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s{//.*}{}g;
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s{\b((defined|if)\ YYDEBUG
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|YYChar
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|YYPUSH_MORE(?:_DEFINED)?
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|YYUSE
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|YY_ATTRIBUTE(?:_PURE|_UNUSED)?
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|YY_COPY
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|YY_IGNORE_MAYBE_UNINITIALIZED_(?:BEGIN|END)
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|YY_INITIAL_VALUE
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|YY_MOVE
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|YY_MOVE_OR_COPY
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|YY_MOVE_REF
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|YY_NULLPTR
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|YY_RVREF
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|YY_\w+_INCLUDED
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)\b}{}gx;
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while (/^(.*YY.*)$/gm)
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{
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print "$ARGV: invalid exported YY: $1\n";
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}
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if ($ARGV =~ /\.h$/)
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{
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while (/^(.*yy.*)$/gm)
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{
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print "$ARGV: invalid exported yy: $1\n";
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}
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}
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' -- *.hh *.h]])
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# Do this late, so that other checks have been performed.
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AT_SKIP_IF_CANNOT_LINK_C_AND_CXX
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AT_COMPILE_CXX([parser], [[x[1-8].o -DCC_IS_CXX=$CC_IS_CXX main.cc]])
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AT_PARSER_CHECK([./parser], [0], [[expout]])
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m4_popdef([AT_TEST])
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AT_CLEANUP
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