# Exercising Bison on conflicts. -*- Autotest -*-
# Copyright (C) 2002, 2003, 2004, 2005 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, 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., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
AT_BANNER([[Conflicts.]])
## ---------------- ##
## S/R in initial. ##
## ---------------- ##
# I once hacked Bison in such a way that it lost its reductions on the
# initial state (because it was confusing it with the last state). It
# took me a while to strip down my failures to this simple case. So
# make sure it finds the s/r conflict below.
AT_SETUP([S/R in initial])
AT_DATA([[input.y]],
[[%expect 1
%%
exp: e 'e';
e: 'e' | /* Nothing. */;
]])
AT_CHECK([bison -o input.c input.y], 0, [],
[[input.y:4.9: warning: rule never reduced because of conflicts: e: /* empty */
]])
AT_CLEANUP
## ------------------- ##
## %nonassoc and eof. ##
## ------------------- ##
AT_SETUP([%nonassoc and eof])
AT_DATA_GRAMMAR([input.y],
[[
%{
#include <stdio.h>
#include <stdlib.h>
#define YYERROR_VERBOSE 1
static void
yyerror (const char *msg)
{
fprintf (stderr, "%s\n", msg);
}
/* The current argument. */
static const char *input = NULL;
static int
yylex (void)
{
/* No token stands for end of file. */
if (input && *input)
return *input++;
else
return 0;
}
%}
%nonassoc '<' '>'
%%
expr: expr '<' expr
| expr '>' expr
| '0'
;
%%
int
main (int argc, const char *argv[])
{
if (argc > 1)
input = argv[1];
return yyparse ();
}
]])
# Specify the output files to avoid problems on different file systems.
AT_CHECK([bison -o input.c input.y])
AT_COMPILE([input])
AT_PARSER_CHECK([./input '0<0'])
# FIXME: This is an actual bug, but a new one, in the sense that
# no one has ever spotted it! The messages are *wrong*: there should
# be nothing there, it should be expected eof.
AT_PARSER_CHECK([./input '0<0<0'], [1], [],
[syntax error, unexpected '<', expecting '<' or '>'
])
AT_PARSER_CHECK([./input '0>0'])
AT_PARSER_CHECK([./input '0>0>0'], [1], [],
[syntax error, unexpected '>', expecting '<' or '>'
])
AT_PARSER_CHECK([./input '0<0>0'], [1], [],
[syntax error, unexpected '>', expecting '<' or '>'
])
AT_CLEANUP
## ------------------------- ##
## Unresolved SR Conflicts. ##
## ------------------------- ##
AT_SETUP([Unresolved SR Conflicts])
AT_KEYWORDS([report])
AT_DATA([input.y],
[[%token NUM OP
%%
exp: exp OP exp | NUM;
]])
AT_CHECK([bison -o input.c --report=all input.y], 0, [],
[input.y: conflicts: 1 shift/reduce
])
# Check the contents of the report.
AT_CHECK([cat input.output], [],
[[State 5 conflicts: 1 shift/reduce
Grammar
0 $accept: exp $end
1 exp: exp OP exp
2 | NUM
Terminals, with rules where they appear
$end (0) 0
error (256)
NUM (258) 2
OP (259) 1
Nonterminals, with rules where they appear
$accept (5)
on left: 0
exp (6)
on left: 1 2, on right: 0 1
state 0
0 $accept: . exp $end
1 exp: . exp OP exp
2 | . NUM
NUM shift, and go to state 1
exp go to state 2
state 1
2 exp: NUM .
$default reduce using rule 2 (exp)
state 2
0 $accept: exp . $end
1 exp: exp . OP exp
$end shift, and go to state 3
OP shift, and go to state 4
state 3
0 $accept: exp $end .
$default accept
state 4
1 exp: . exp OP exp
1 | exp OP . exp
2 | . NUM
NUM shift, and go to state 1
exp go to state 5
state 5
1 exp: exp . OP exp [$end, OP]
1 | exp OP exp . [$end, OP]
OP shift, and go to state 4
OP [reduce using rule 1 (exp)]
$default reduce using rule 1 (exp)
]])
AT_CLEANUP
## ----------------------- ##
## Resolved SR Conflicts. ##
## ----------------------- ##
AT_SETUP([Resolved SR Conflicts])
AT_KEYWORDS([report])
AT_DATA([input.y],
[[%token NUM OP
%left OP
%%
exp: exp OP exp | NUM;
]])
AT_CHECK([bison -o input.c --report=all input.y])
# Check the contents of the report.
AT_CHECK([cat input.output], [],
[[Grammar
0 $accept: exp $end
1 exp: exp OP exp
2 | NUM
Terminals, with rules where they appear
$end (0) 0
error (256)
NUM (258) 2
OP (259) 1
Nonterminals, with rules where they appear
$accept (5)
on left: 0
exp (6)
on left: 1 2, on right: 0 1
state 0
0 $accept: . exp $end
1 exp: . exp OP exp
2 | . NUM
NUM shift, and go to state 1
exp go to state 2
state 1
2 exp: NUM .
$default reduce using rule 2 (exp)
state 2
0 $accept: exp . $end
1 exp: exp . OP exp
$end shift, and go to state 3
OP shift, and go to state 4
state 3
0 $accept: exp $end .
$default accept
state 4
1 exp: . exp OP exp
1 | exp OP . exp
2 | . NUM
NUM shift, and go to state 1
exp go to state 5
state 5
1 exp: exp . OP exp [$end, OP]
1 | exp OP exp . [$end, OP]
$default reduce using rule 1 (exp)
Conflict between rule 1 and token OP resolved as reduce (%left OP).
]])
AT_CLEANUP
## -------------------------------- ##
## Defaulted Conflicted Reduction. ##
## -------------------------------- ##
# When there are RR conflicts, some rules are disabled. Usually it is
# simply displayed as:
#
# $end reduce using rule 3 (num)
# $end [reduce using rule 4 (id)]
#
# But when `reduce 3' is the default action, we'd produce:
#
# $end [reduce using rule 4 (id)]
# $default reduce using rule 3 (num)
#
# In this precise case (a reduction is masked by the default
# reduction), we make the `reduce 3' explicit:
#
# $end reduce using rule 3 (num)
# $end [reduce using rule 4 (id)]
# $default reduce using rule 3 (num)
#
# Maybe that's not the best display, but then, please propose something
# else.
AT_SETUP([Defaulted Conflicted Reduction])
AT_KEYWORDS([report])
AT_DATA([input.y],
[[%%
exp: num | id;
num: '0';
id : '0';
%%
]])
AT_CHECK([bison -o input.c --report=all input.y], 0, [],
[[input.y: conflicts: 1 reduce/reduce
input.y:4.6-8: warning: rule never reduced because of conflicts: id: '0'
]])
# Check the contents of the report.
AT_CHECK([cat input.output], [],
[[Rules never reduced
4 id: '0'
State 1 conflicts: 1 reduce/reduce
Grammar
0 $accept: exp $end
1 exp: num
2 | id
3 num: '0'
4 id: '0'
Terminals, with rules where they appear
$end (0) 0
'0' (48) 3 4
error (256)
Nonterminals, with rules where they appear
$accept (4)
on left: 0
exp (5)
on left: 1 2, on right: 0
num (6)
on left: 3, on right: 1
id (7)
on left: 4, on right: 2
state 0
0 $accept: . exp $end
1 exp: . num
2 | . id
3 num: . '0'
4 id: . '0'
'0' shift, and go to state 1
exp go to state 2
num go to state 3
id go to state 4
state 1
3 num: '0' . [$end]
4 id: '0' . [$end]
$end reduce using rule 3 (num)
$end [reduce using rule 4 (id)]
$default reduce using rule 3 (num)
state 2
0 $accept: exp . $end
$end shift, and go to state 5
state 3
1 exp: num .
$default reduce using rule 1 (exp)
state 4
2 exp: id .
$default reduce using rule 2 (exp)
state 5
0 $accept: exp $end .
$default accept
]])
AT_CLEANUP
## -------------------- ##
## %expect not enough. ##
## -------------------- ##
AT_SETUP([%expect not enough])
AT_DATA([input.y],
[[%token NUM OP
%expect 0
%%
exp: exp OP exp | NUM;
]])
AT_CHECK([bison -o input.c input.y], 1, [],
[input.y: conflicts: 1 shift/reduce
input.y: expected 0 shift/reduce conflicts
])
AT_CLEANUP
## --------------- ##
## %expect right. ##
## --------------- ##
AT_SETUP([%expect right])
AT_DATA([input.y],
[[%token NUM OP
%expect 1
%%
exp: exp OP exp | NUM;
]])
AT_CHECK([bison -o input.c input.y])
AT_CLEANUP
## ------------------ ##
## %expect too much. ##
## ------------------ ##
AT_SETUP([%expect too much])
AT_DATA([input.y],
[[%token NUM OP
%expect 2
%%
exp: exp OP exp | NUM;
]])
AT_CHECK([bison -o input.c input.y], 1, [],
[input.y: conflicts: 1 shift/reduce
input.y: expected 2 shift/reduce conflicts
])
AT_CLEANUP
## ------------------------------ ##
## %expect with reduce conflicts ##
## ------------------------------ ##
AT_SETUP([%expect with reduce conflicts])
AT_DATA([input.y],
[[%expect 0
%%
program: a 'a' | a a;
a: 'a';
]])
AT_CHECK([bison -o input.c input.y], 1, [],
[input.y: conflicts: 1 reduce/reduce
input.y: expected 0 reduce/reduce conflicts
])
AT_CLEANUP
## ------------------------------- ##
## %no-default-prec without %prec ##
## ------------------------------- ##
AT_SETUP([%no-default-prec without %prec])
AT_DATA([[input.y]],
[[%left '+'
%left '*'
%%
%no-default-prec;
e: e '+' e
| e '*' e
| '0'
;
]])
AT_CHECK([bison -o input.c input.y], 0, [],
[[input.y: conflicts: 4 shift/reduce
]])
AT_CLEANUP
## ---------------------------- ##
## %no-default-prec with %prec ##
## ---------------------------- ##
AT_SETUP([%no-default-prec with %prec])
AT_DATA([[input.y]],
[[%left '+'
%left '*'
%%
%no-default-prec;
e: e '+' e %prec '+'
| e '*' e %prec '*'
| '0'
;
]])
AT_CHECK([bison -o input.c input.y])
AT_CLEANUP
## ---------------- ##
## %default-prec ##
## ---------------- ##
AT_SETUP([%default-prec])
AT_DATA([[input.y]],
[[%left '+'
%left '*'
%%
%default-prec;
e: e '+' e
| e '*' e
| '0'
;
]])
AT_CHECK([bison -o input.c input.y])
AT_CLEANUP