path: root/tests/conflicts.at

# Exercising Bison on conflicts.                         -*- Autotest -*-
# Copyright (C) 2002 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., 59 Temple Place - Suite 330, Boston, MA
# 02111-1307, 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 input.y -o input.c])

AT_CLEANUP

## ------------------- ##
## %nonassoc and eof.  ##
## ------------------- ##

AT_SETUP([%nonassoc and eof])

AT_DATA([input.y],
[[
%{
#include <config.h>
/* We don't need a perfect malloc for these tests. */
#undef malloc
#include <stdio.h>

#if STDC_HEADERS
# include <stdlib.h>
#endif

#define YYERROR_VERBOSE 1
static void
yyerror (const char *msg)
{
  fprintf (stderr, "%s\n", msg);
  exit (1);
}

/* 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 input.y -o input.c])
AT_CHECK([$CC $CFLAGS $CPPFLAGS input.c -o input], 0, [], [ignore])

AT_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_CHECK([./input '0<0<0'], [1], [],
         [parse error, unexpected '<', expecting '<' or '>'
])

AT_CHECK([./input '0>0'])
AT_CHECK([./input '0>0>0'], [1], [],
         [parse error, unexpected '>', expecting '<' or '>'
])

AT_CHECK([./input '0<0>0'], [1], [],
         [parse error, unexpected '>', expecting '<' or '>'
])

AT_CLEANUP



## ------------------------- ##
## Unresolved SR Conflicts.  ##
## ------------------------- ##

AT_SETUP([Unresolved SR Conflicts])

AT_DATA([input.y],
[[%token NUM OP
%%
exp: exp OP exp | NUM;
]])

AT_CHECK([bison input.y -o input.c -v], 0, [],
[input.y contains 1 shift/reduce conflict.
])

# Check the contents of the report.
AT_CHECK([cat input.output], [],
[[State 5 contains 1 shift/reduce conflict.


Grammar

  Number, Line, Rule
    0   3 $axiom -> exp $
    1   3 exp -> exp OP exp
    2   3 exp -> NUM


Terminals, with rules where they appear

$ (0) 0
error (256)
NUM (258) 2
OP (259) 1


Nonterminals, with rules where they appear

$axiom (5)
    on left: 0
exp (6)
    on left: 1 2, on right: 0 1


state 0

    $axiom  ->  . exp $   (rule 0)

    NUM 	shift, and go to state 1

    exp 	go to state 2



state 1

    exp  ->  NUM .   (rule 2)

    $default	reduce using rule 2 (exp)



state 2

    $axiom  ->  exp . $   (rule 0)
    exp  ->  exp . OP exp   (rule 1)

    $   	shift, and go to state 3
    OP  	shift, and go to state 4



state 3

    $axiom  ->  exp $ .   (rule 0)

    $default	accept


state 4

    exp  ->  exp OP . exp   (rule 1)

    NUM 	shift, and go to state 1

    exp 	go to state 5



state 5

    exp  ->  exp . OP exp   (rule 1)
    exp  ->  exp OP exp .   (rule 1)

    OP  	shift, and go to state 4

    OP  	[reduce using rule 1 (exp)]
    $default	reduce using rule 1 (exp)



]])

AT_CLEANUP


## --------------------- ##
## Solved SR Conflicts.  ##
## --------------------- ##

AT_SETUP([Solved SR Conflicts])

AT_DATA([input.y],
[[%token NUM OP
%right OP
%%
exp: exp OP exp | NUM;
]])

AT_CHECK([bison input.y -o input.c -v], 0, [], [])

# Check the contents of the report.
AT_CHECK([cat input.output], [],
[[Conflict in state 5 between rule 2 and token OP resolved as shift.


Grammar

  Number, Line, Rule
    0   4 $axiom -> exp $
    1   4 exp -> exp OP exp
    2   4 exp -> NUM


Terminals, with rules where they appear

$ (0) 0
error (256)
NUM (258) 2
OP (259) 1


Nonterminals, with rules where they appear

$axiom (5)
    on left: 0
exp (6)
    on left: 1 2, on right: 0 1


state 0

    $axiom  ->  . exp $   (rule 0)

    NUM 	shift, and go to state 1

    exp 	go to state 2



state 1

    exp  ->  NUM .   (rule 2)

    $default	reduce using rule 2 (exp)



state 2

    $axiom  ->  exp . $   (rule 0)
    exp  ->  exp . OP exp   (rule 1)

    $   	shift, and go to state 3
    OP  	shift, and go to state 4



state 3

    $axiom  ->  exp $ .   (rule 0)

    $default	accept


state 4

    exp  ->  exp OP . exp   (rule 1)

    NUM 	shift, and go to state 1

    exp 	go to state 5



state 5

    exp  ->  exp . OP exp   (rule 1)
    exp  ->  exp OP exp .   (rule 1)

    OP  	shift, and go to state 4

    $default	reduce using rule 1 (exp)



]])

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 input.y -o input.c], 1, [],
[input.y contains 1 shift/reduce conflict.
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 input.y -o input.c], 0)
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 input.y -o input.c], 1, [],
[input.y contains 1 shift/reduce conflict.
expected 2 shift/reduce conflicts
])
AT_CLEANUP