mirror of
https://git.savannah.gnu.org/git/bison.git
synced 2026-03-09 12:23:04 +00:00
622 lines
9.9 KiB
Plaintext
622 lines
9.9 KiB
Plaintext
# Exercising Bison on conflicts. -*- Autotest -*-
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# Copyright (C) 2002, 2003, 2004 Free Software 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 2, or (at your option)
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# any later version.
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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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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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# 02111-1307, USA.
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AT_BANNER([[Conflicts.]])
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## ---------------- ##
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## S/R in initial. ##
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## ---------------- ##
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# I once hacked Bison in such a way that it lost its reductions on the
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# initial state (because it was confusing it with the last state). It
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# took me a while to strip down my failures to this simple case. So
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# make sure it finds the s/r conflict below.
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AT_SETUP([S/R in initial])
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AT_DATA([[input.y]],
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[[%expect 1
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%%
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exp: e 'e';
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e: 'e' | /* Nothing. */;
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]])
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AT_CHECK([bison -o input.c input.y], 0, [],
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[[input.y:4.9: warning: rule never reduced because of conflicts: e: /* empty */
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]])
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AT_CLEANUP
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## ------------------- ##
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## %nonassoc and eof. ##
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## ------------------- ##
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AT_SETUP([%nonassoc and eof])
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AT_DATA_GRAMMAR([input.y],
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[[
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%{
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#include <stdio.h>
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#include <stdlib.h>
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#define YYERROR_VERBOSE 1
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static void
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yyerror (const char *msg)
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{
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fprintf (stderr, "%s\n", msg);
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exit (1);
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}
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/* The current argument. */
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static const char *input = NULL;
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static int
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yylex (void)
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{
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/* No token stands for end of file. */
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if (input && *input)
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return *input++;
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else
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return 0;
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}
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%}
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%nonassoc '<' '>'
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%%
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expr: expr '<' expr
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| expr '>' expr
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| '0'
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;
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%%
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int
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main (int argc, const char *argv[])
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{
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if (argc > 1)
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input = argv[1];
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return yyparse ();
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}
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]])
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# Specify the output files to avoid problems on different file systems.
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AT_CHECK([bison -o input.c input.y])
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AT_COMPILE([input])
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AT_PARSER_CHECK([./input '0<0'])
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# FIXME: This is an actual bug, but a new one, in the sense that
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# no one has ever spotted it! The messages are *wrong*: there should
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# be nothing there, it should be expected eof.
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AT_PARSER_CHECK([./input '0<0<0'], [1], [],
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[syntax error, unexpected '<', expecting '<' or '>'
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])
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AT_PARSER_CHECK([./input '0>0'])
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AT_PARSER_CHECK([./input '0>0>0'], [1], [],
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[syntax error, unexpected '>', expecting '<' or '>'
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])
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AT_PARSER_CHECK([./input '0<0>0'], [1], [],
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[syntax error, unexpected '>', expecting '<' or '>'
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])
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AT_CLEANUP
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## ------------------------- ##
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## Unresolved SR Conflicts. ##
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## ------------------------- ##
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AT_SETUP([Unresolved SR Conflicts])
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AT_KEYWORDS([report])
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AT_DATA([input.y],
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[[%token NUM OP
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%%
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exp: exp OP exp | NUM;
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]])
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AT_CHECK([bison -o input.c --report=all input.y], 0, [],
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[input.y: conflicts: 1 shift/reduce
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])
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# Check the contents of the report.
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AT_CHECK([cat input.output], [],
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[[State 5 conflicts: 1 shift/reduce
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Grammar
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0 $accept: exp $end
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1 exp: exp OP exp
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2 | NUM
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Terminals, with rules where they appear
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$end (0) 0
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error (256)
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NUM (258) 2
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OP (259) 1
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Nonterminals, with rules where they appear
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$accept (5)
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on left: 0
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exp (6)
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on left: 1 2, on right: 0 1
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state 0
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0 $accept: . exp $end
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1 exp: . exp OP exp
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2 | . NUM
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NUM shift, and go to state 1
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exp go to state 2
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state 1
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2 exp: NUM .
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$default reduce using rule 2 (exp)
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state 2
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0 $accept: exp . $end
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1 exp: exp . OP exp
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$end shift, and go to state 3
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OP shift, and go to state 4
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state 3
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0 $accept: exp $end .
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$default accept
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state 4
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1 exp: . exp OP exp
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1 | exp OP . exp
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2 | . NUM
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NUM shift, and go to state 1
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exp go to state 5
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state 5
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1 exp: exp . OP exp [$end, OP]
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1 | exp OP exp . [$end, OP]
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OP shift, and go to state 4
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OP [reduce using rule 1 (exp)]
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$default reduce using rule 1 (exp)
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]])
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AT_CLEANUP
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## ----------------------- ##
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## Resolved SR Conflicts. ##
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## ----------------------- ##
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AT_SETUP([Resolved SR Conflicts])
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AT_KEYWORDS([report])
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AT_DATA([input.y],
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[[%token NUM OP
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%left OP
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%%
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exp: exp OP exp | NUM;
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]])
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AT_CHECK([bison -o input.c --report=all input.y])
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# Check the contents of the report.
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AT_CHECK([cat input.output], [],
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[[Grammar
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0 $accept: exp $end
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1 exp: exp OP exp
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2 | NUM
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Terminals, with rules where they appear
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$end (0) 0
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error (256)
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NUM (258) 2
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OP (259) 1
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Nonterminals, with rules where they appear
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$accept (5)
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on left: 0
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exp (6)
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on left: 1 2, on right: 0 1
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state 0
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0 $accept: . exp $end
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1 exp: . exp OP exp
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2 | . NUM
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NUM shift, and go to state 1
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exp go to state 2
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state 1
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2 exp: NUM .
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$default reduce using rule 2 (exp)
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state 2
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0 $accept: exp . $end
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1 exp: exp . OP exp
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$end shift, and go to state 3
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OP shift, and go to state 4
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state 3
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0 $accept: exp $end .
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$default accept
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state 4
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1 exp: . exp OP exp
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1 | exp OP . exp
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2 | . NUM
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NUM shift, and go to state 1
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exp go to state 5
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state 5
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1 exp: exp . OP exp [$end, OP]
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1 | exp OP exp . [$end, OP]
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$default reduce using rule 1 (exp)
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Conflict between rule 1 and token OP resolved as reduce (%left OP).
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]])
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AT_CLEANUP
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## -------------------------------- ##
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## Defaulted Conflicted Reduction. ##
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## -------------------------------- ##
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# When there are RR conflicts, some rules are disabled. Usually it is
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# simply displayed as:
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#
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# $end reduce using rule 3 (num)
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# $end [reduce using rule 4 (id)]
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#
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# But when `reduce 3' is the default action, we'd produce:
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#
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# $end [reduce using rule 4 (id)]
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# $default reduce using rule 3 (num)
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#
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# In this precise case (a reduction is masked by the default
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# reduction), we make the `reduce 3' explicit:
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#
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# $end reduce using rule 3 (num)
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# $end [reduce using rule 4 (id)]
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# $default reduce using rule 3 (num)
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#
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# Maybe that's not the best display, but then, please propose something
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# else.
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AT_SETUP([Defaulted Conflicted Reduction])
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AT_KEYWORDS([report])
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AT_DATA([input.y],
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[[%%
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exp: num | id;
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num: '0';
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id : '0';
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%%
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]])
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AT_CHECK([bison -o input.c --report=all input.y], 0, [],
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[[input.y: conflicts: 1 reduce/reduce
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input.y:4.6-8: warning: rule never reduced because of conflicts: id: '0'
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]])
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# Check the contents of the report.
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AT_CHECK([cat input.output], [],
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[[Rules never reduced
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4 id: '0'
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State 1 conflicts: 1 reduce/reduce
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Grammar
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0 $accept: exp $end
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1 exp: num
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2 | id
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3 num: '0'
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4 id: '0'
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Terminals, with rules where they appear
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$end (0) 0
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'0' (48) 3 4
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error (256)
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Nonterminals, with rules where they appear
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$accept (4)
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on left: 0
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exp (5)
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on left: 1 2, on right: 0
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num (6)
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on left: 3, on right: 1
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id (7)
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on left: 4, on right: 2
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state 0
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0 $accept: . exp $end
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1 exp: . num
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2 | . id
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3 num: . '0'
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4 id: . '0'
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'0' shift, and go to state 1
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exp go to state 2
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num go to state 3
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id go to state 4
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state 1
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3 num: '0' . [$end]
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4 id: '0' . [$end]
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$end reduce using rule 3 (num)
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$end [reduce using rule 4 (id)]
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$default reduce using rule 3 (num)
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state 2
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0 $accept: exp . $end
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$end shift, and go to state 5
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state 3
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1 exp: num .
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$default reduce using rule 1 (exp)
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state 4
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2 exp: id .
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$default reduce using rule 2 (exp)
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state 5
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0 $accept: exp $end .
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$default accept
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]])
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AT_CLEANUP
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## -------------------- ##
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## %expect not enough. ##
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## -------------------- ##
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AT_SETUP([%expect not enough])
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AT_DATA([input.y],
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[[%token NUM OP
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%expect 0
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%%
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exp: exp OP exp | NUM;
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]])
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AT_CHECK([bison -o input.c input.y], 0, [],
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[input.y: conflicts: 1 shift/reduce
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input.y: warning: expected 0 shift/reduce conflicts
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])
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AT_CLEANUP
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## --------------- ##
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## %expect right. ##
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## --------------- ##
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AT_SETUP([%expect right])
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AT_DATA([input.y],
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[[%token NUM OP
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%expect 1
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%%
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exp: exp OP exp | NUM;
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]])
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AT_CHECK([bison -o input.c input.y])
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AT_CLEANUP
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## ------------------ ##
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## %expect too much. ##
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## ------------------ ##
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AT_SETUP([%expect too much])
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AT_DATA([input.y],
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[[%token NUM OP
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%expect 2
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%%
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exp: exp OP exp | NUM;
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]])
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AT_CHECK([bison -o input.c input.y], 0, [],
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[input.y: conflicts: 1 shift/reduce
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input.y: warning: expected 2 shift/reduce conflicts
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])
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AT_CLEANUP
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## ------------------------------ ##
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## %expect with reduce conflicts ##
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## ------------------------------ ##
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AT_SETUP([%expect with reduce conflicts])
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AT_DATA([input.y],
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[[%expect 0
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%%
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program: a 'a' | a a;
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a: 'a';
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]])
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AT_CHECK([bison -o input.c input.y], 0, [],
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[input.y: conflicts: 1 reduce/reduce
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input.y: warning: expected 0 reduce/reduce conflicts
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])
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AT_CLEANUP
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## ------------------------------- ##
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## %no-default-prec without %prec ##
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## ------------------------------- ##
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AT_SETUP([%no-default-prec without %prec])
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AT_DATA([[input.y]],
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[[%left '+'
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%left '*'
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%%
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%no-default-prec;
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e: e '+' e
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| e '*' e
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| '0'
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;
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]])
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AT_CHECK([bison -o input.c input.y], 0, [],
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[[input.y: conflicts: 4 shift/reduce
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]])
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AT_CLEANUP
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## ---------------------------- ##
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## %no-default-prec with %prec ##
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## ---------------------------- ##
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AT_SETUP([%no-default-prec with %prec])
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AT_DATA([[input.y]],
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[[%left '+'
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%left '*'
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%%
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%no-default-prec;
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e: e '+' e %prec '+'
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| e '*' e %prec '*'
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| '0'
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;
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]])
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AT_CHECK([bison -o input.c input.y])
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AT_CLEANUP
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## ---------------- ##
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## %default-prec ##
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## ---------------- ##
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AT_SETUP([%default-prec])
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AT_DATA([[input.y]],
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[[%left '+'
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%left '*'
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%%
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%default-prec;
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e: e '+' e
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| e '*' e
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| '0'
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;
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]])
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AT_CHECK([bison -o input.c input.y])
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AT_CLEANUP
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