# Checking GLR Parsing: Regression Tests -*- Autotest -*-
-# Copyright (C) 2002, 2003, 2005, 2006 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.
+# Copyright (C) 2002-2003, 2005-2007, 2009-2012 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 3 of the License, 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.
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
AT_BANNER([[GLR Regression Tests]])
%{
#include <stdio.h>
+#include <stdlib.h>
#define YYSTYPE int
static YYSTYPE exprMerge (YYSTYPE x0, YYSTYPE x1);
{
for (;;)
{
- int ch = getchar ();
+ int ch;
+ if (feof (stdin))
+ abort ();
+ ch = getchar ();
if (ch == EOF)
return 0;
else if (ch == 'B' || ch == 'P')
}
]])
-AT_CHECK([[bison -o glr-regr1.c glr-regr1.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr1.c glr-regr1.y]], 0, [],
[glr-regr1.y: conflicts: 1 shift/reduce
])
AT_COMPILE([glr-regr1])
-AT_CHECK([[echo BPBPB | ./glr-regr1]], 0,
+AT_PARSER_CHECK([[echo BPBPB | ./glr-regr1]], 0,
[[E -> 'B'
E -> 'B'
E -> E 'P' E
%%
-FILE *input = NULL;
+FILE *input;
int
yylex (void)
{
char buf[50];
char *s;
+ if (feof (stdin))
+ abort ();
switch (fscanf (input, " %1[a-z,]", buf)) {
case 1:
return buf[0];
}
]])
-AT_CHECK([[bison -o glr-regr2a.c glr-regr2a.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr2a.c glr-regr2a.y]], 0, [],
[glr-regr2a.y: conflicts: 2 shift/reduce
])
AT_COMPILE([glr-regr2a])
-AT_CHECK([[echo s VARIABLE_1 t v x q | ./glr-regr2a]], 0,
+AT_PARSER_CHECK([[echo s VARIABLE_1 t v x q | ./glr-regr2a]], 0,
[[Variable: 'VARIABLE_1'
]], [])
-AT_CHECK([[echo s VARIABLE_1 , ANOTHER_VARIABLE_2 t e | ./glr-regr2a]], 0,
+AT_PARSER_CHECK([[echo s VARIABLE_1 , ANOTHER_VARIABLE_2 t e | ./glr-regr2a]],
+0,
[[Varlist: 'VARIABLE_1,ANOTHER_VARIABLE_2'
]])
-AT_CHECK([[echo s VARIABLE_3 t v x | ./glr-regr2a]], 0,
+AT_PARSER_CHECK([[echo s VARIABLE_3 t v x | ./glr-regr2a]], 0,
[[Variable: 'VARIABLE_3'
]], [])
%{
#include <stdio.h>
+#include <stdlib.h>
#include <stdarg.h>
static int MergeRule (int x0, int x1);
fprintf(stderr,"error: %s\n",s);
}
-FILE *input = NULL;
+FILE *input = YY_NULL;
int P[] = { P1, P2 };
int O[] = { O1, O2 };
int yylex (void)
{
char inp[3];
+ if (feof (stdin))
+ abort ();
if (fscanf (input, "%2s", inp) == EOF)
return 0;
switch (inp[0])
}
]])
-AT_CHECK([[bison -o glr-regr3.c glr-regr3.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr3.c glr-regr3.y]], 0, [],
[glr-regr3.y: conflicts: 1 shift/reduce, 1 reduce/reduce
])
AT_COMPILE([glr-regr3])
-AT_CHECK([[echo p1 t4 o2 p1 p1 t1 o1 t2 p2 o1 t3 p2 p2 | ./glr-regr3]], 0,
+AT_PARSER_CHECK([[echo p1 t4 o2 p1 p1 t1 o1 t2 p2 o1 t3 p2 p2 | ./glr-regr3]],
+0,
[[Result: 1c04
]], [])
static char *make_value (char const *, char const *);
static void yyerror (char const *);
static int yylex (void);
+ static char *ptrs[100];
+ static char **ptrs_next = ptrs;
%}
%%
static int
yylex (void)
{
- static char const *input = "a";
- return *input++;
+ static char const input[] = "a";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
+ return input[toknum++];
}
int
main (void)
{
- return yyparse ();
+ int status = yyparse ();
+ while (ptrs_next != ptrs)
+ free (*--ptrs_next);
+ return status;
}
static char *
make_value (char const *parent, char const *child)
{
char const format[] = "%s <- %s";
- char *value =
+ char *value = *ptrs_next++ =
(char *) malloc (strlen (parent) + strlen (child) + sizeof format);
sprintf (value, format, parent, child);
return value;
merge (YYSTYPE s1, YYSTYPE s2)
{
char const format[] = "merge{ %s and %s }";
- char *value =
+ char *value = *ptrs_next++ =
(char *) malloc (strlen (s1.ptr) + strlen (s2.ptr) + sizeof format);
sprintf (value, format, s1.ptr, s2.ptr);
return value;
}
]])
-AT_CHECK([[bison -o glr-regr4.c glr-regr4.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr4.c glr-regr4.y]], 0, [],
[glr-regr4.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr4])
-AT_CHECK([[./glr-regr4]], 0,
+AT_PARSER_CHECK([[./glr-regr4]], 0,
[[merge{ S <- merge{ A <- A1 <- 'a' and A <- A2 <- 'a' } and S <- B <- 'a' }
]], [])
static int
yylex (void)
{
- static char const *input = "a";
- return *input++;
+ static char const input[] = "a";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
+ return input[toknum++];
}
static void
}
]])
-AT_CHECK([[bison -o glr-regr5.c glr-regr5.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr5.c glr-regr5.y]], 0, [],
[glr-regr5.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr5])
-AT_CHECK([[./glr-regr5]], 0, [],
+AT_PARSER_CHECK([[./glr-regr5]], 0, [],
[syntax is ambiguous
])
static int
yylex (void)
{
- static char const *input = "a";
- return *input++;
+ static char const input[] = "a";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
+ return input[toknum++];
}
static void
}
]])
-AT_CHECK([[bison -o glr-regr6.c glr-regr6.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr6.c glr-regr6.y]], 0, [],
[glr-regr6.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr6])
-AT_CHECK([[./glr-regr6]], 0,
+AT_PARSER_CHECK([[./glr-regr6]], 0,
[Destructor called.
],
[syntax is ambiguous
static void yyerror (char const *);
static int yylex (void);
#define YYSTACKEXPANDABLE 0
+ typedef struct count_node {
+ int count;
+ struct count_node *prev;
+ } count_node;
+ static count_node *tail;
%}
%glr-parser
-%union { int *count; }
-%type <count> 'a'
+%union { count_node *node; }
+%type <node> 'a'
%destructor {
- if ((*$$)++)
+ if ($$->count++)
fprintf (stderr, "Destructor called on same value twice.\n");
} 'a'
static int
yylex (void)
{
- yylval.count = (int *) malloc (sizeof (int));
- if (!yylval.count)
+ yylval.node = (count_node*) malloc (sizeof *yylval.node);
+ if (!yylval.node)
{
fprintf (stderr, "Test inconclusive.\n");
exit (EXIT_FAILURE);
}
- *yylval.count = 0;
+ yylval.node->count = 0;
+ yylval.node->prev = tail;
+ tail = yylval.node;
return 'a';
}
int
main (void)
{
- return yyparse ();
+ int status = yyparse ();
+ while (tail)
+ {
+ count_node *prev = tail->prev;
+ free (tail);
+ tail = prev;
+ }
+ return status;
}
]])
-AT_CHECK([[bison -o glr-regr7.c glr-regr7.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr7.c glr-regr7.y]], 0, [],
[glr-regr7.y: conflicts: 2 reduce/reduce
])
AT_COMPILE([glr-regr7])
-AT_CHECK([[./glr-regr7]], 2, [],
+AT_PARSER_CHECK([[./glr-regr7]], 2, [],
[memory exhausted
])
lexIndex += 1;
switch (lexIndex)
{
+ default:
+ abort ();
case 1:
yylloc.first_column = 1;
yylloc.last_column = 9;
yylloc.first_column = 13;
yylloc.last_column = 17;
return T_PORT;
- default:
+ case 3:
return 0;
}
}
}
]])
-AT_CHECK([[bison -o glr-regr8.c glr-regr8.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr8.c glr-regr8.y]], 0, [],
[glr-regr8.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr8])
-AT_CHECK([[./glr-regr8]], 0,
+AT_PARSER_CHECK([[./glr-regr8]], 0,
[empty: 9/9
1/9 - 9/9 - 13/17
],
}
]])
-AT_CHECK([[bison -o glr-regr9.c glr-regr9.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr9.c glr-regr9.y]], 0, [],
[glr-regr9.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr9])
-AT_CHECK([[./glr-regr9]], 0, [],
+AT_PARSER_CHECK([[./glr-regr9]], 0, [],
[memory exhausted
])
AT_DATA_GRAMMAR([glr-regr10.y],
[[
%{
+# include <stdlib.h>
# include <stdio.h>
static void yyerror (char const *);
static int yylex (void);
static int
yylex (void)
{
+ static int called;
+ if (called++)
+ abort ();
return 0;
}
}
]])
-AT_CHECK([[bison -o glr-regr10.c glr-regr10.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr10.c glr-regr10.y]], 0, [],
[glr-regr10.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr10])
-AT_CHECK([[./glr-regr10]], 0, [], [])
+AT_PARSER_CHECK([[./glr-regr10]], 0, [], [])
AT_CLEANUP
static int
yylex (void)
{
- static char const *input = "a";
- return *input++;
+ static char const input[] = "a";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
+ return input[toknum++];
}
int
}
]])
-AT_CHECK([[bison -o glr-regr11.c glr-regr11.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr11.c glr-regr11.y]], 0, [],
[glr-regr11.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr11])
-AT_CHECK([[./glr-regr11]], 0, [], [])
+AT_PARSER_CHECK([[./glr-regr11]], 0, [], [])
AT_CLEANUP
start:
alt1 %dprec 1
| alt2 %dprec 2
- ;
+ ;
alt1:
PARENT_RHS_AFTER {
yylex (void)
{
static int const input[] = { PARENT_RHS_AFTER, 0 };
- static const int *inputp = input;
- if (*inputp == PARENT_RHS_AFTER)
+ static size_t toknum;
+ if (! (toknum < sizeof input / sizeof *input))
+ abort ();
+ if (input[toknum] == PARENT_RHS_AFTER)
parent_rhs_after_value = 1;
- return *inputp++;
+ return input[toknum++];
}
int
}
]])
-AT_CHECK([[bison -o glr-regr12.c glr-regr12.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr12.c glr-regr12.y]], 0, [],
[glr-regr12.y: conflicts: 1 shift/reduce, 1 reduce/reduce
])
AT_COMPILE([glr-regr12])
-AT_CHECK([[./glr-regr12]], 0, [], [])
+AT_PARSER_CHECK([[./glr-regr12]], 0, [], [])
AT_CLEANUP
#include <stdio.h>
static void yyerror (char const *);
static int yylex (void);
- static void print_look_ahead (char const *);
+ static void print_lookahead (char const *);
#define USE(value)
%}
start:
defstate_init defstate_shift 'b' change_lookahead 'a' {
USE ($3);
- print_look_ahead ("start <- defstate_init defstate_shift 'b'");
+ print_lookahead ("start <- defstate_init defstate_shift 'b'");
}
;
defstate_init:
{
- print_look_ahead ("defstate_init <- empty string");
+ print_lookahead ("defstate_init <- empty string");
}
;
defstate_shift:
nondefstate defstate_look 'a' {
USE ($3);
- print_look_ahead ("defstate_shift <- nondefstate defstate_look 'a'");
+ print_lookahead ("defstate_shift <- nondefstate defstate_look 'a'");
}
;
defstate_look:
{
- print_look_ahead ("defstate_look <- empty string");
+ print_lookahead ("defstate_look <- empty string");
}
;
nondefstate:
{
- print_look_ahead ("nondefstate <- empty string");
+ print_lookahead ("nondefstate <- empty string");
}
| 'b' {
USE ($1);
- print_look_ahead ("nondefstate <- 'b'");
+ print_lookahead ("nondefstate <- 'b'");
}
;
change_lookahead:
static int
yylex (void)
{
- static char const *input = "ab";
- static int i = 0;
+ static char const input[] = "ab";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
yylloc.first_line = yylloc.last_line = 1;
- yylloc.first_column = yylloc.last_column = i + 1;
- yylval.value = input[i] + 'A' - 'a';
- return input[i++];
+ yylloc.first_column = yylloc.last_column = toknum + 1;
+ yylval.value = input[toknum] + 'A' - 'a';
+ return input[toknum++];
}
static void
-print_look_ahead (char const *reduction)
+print_lookahead (char const *reduction)
{
printf ("%s:\n yychar=", reduction);
if (yychar == YYEMPTY)
}
]])
-AT_CHECK([[bison -o glr-regr13.c glr-regr13.y]], 0, [], [])
+AT_BISON_CHECK([[-o glr-regr13.c glr-regr13.y]], 0, [], [])
AT_COMPILE([glr-regr13])
-AT_CHECK([[./glr-regr13]], 0,
+AT_PARSER_CHECK([[./glr-regr13]], 0,
[defstate_init <- empty string:
yychar=YYEMPTY
nondefstate <- empty string:
%union { char value; }
%{
+ #include <stdlib.h>
#include <stdio.h>
static void yyerror (char const *);
static int yylex (void);
- static void print_look_ahead (char const *);
+ static void print_lookahead (char const *);
static char merge (union YYSTYPE, union YYSTYPE);
#define USE(value)
%}
start:
merge 'c' stack_explosion {
USE ($2); USE ($3);
- print_look_ahead ("start <- merge 'c' stack_explosion");
+ print_lookahead ("start <- merge 'c' stack_explosion");
}
;
merge:
nonconflict1 'a' 'b' nonconflict2 %dprec 1 {
USE ($2); USE ($3);
- print_look_ahead ("merge <- nonconflict1 'a' 'b' nonconflict2");
+ print_lookahead ("merge <- nonconflict1 'a' 'b' nonconflict2");
}
| conflict defstate_look 'a' nonconflict2 'b' defstate_shift %dprec 2 {
USE ($3); USE ($5);
- print_look_ahead ("merge <- conflict defstate_look 'a' nonconflict2 'b'"
+ print_lookahead ("merge <- conflict defstate_look 'a' nonconflict2 'b'"
" defstate_shift");
}
;
nonconflict1:
{
- print_look_ahead ("nonconflict1 <- empty string");
+ print_lookahead ("nonconflict1 <- empty string");
}
;
nonconflict2:
{
- print_look_ahead ("nonconflict2 <- empty string");
+ print_lookahead ("nonconflict2 <- empty string");
}
| 'a' {
USE ($1);
- print_look_ahead ("nonconflict2 <- 'a'");
+ print_lookahead ("nonconflict2 <- 'a'");
}
;
conflict:
{
- print_look_ahead ("conflict <- empty string");
+ print_lookahead ("conflict <- empty string");
}
;
defstate_look:
{
- print_look_ahead ("defstate_look <- empty string");
+ print_lookahead ("defstate_look <- empty string");
}
;
/* yychar != YYEMPTY but lookahead need is yyfalse. */
defstate_shift:
{
- print_look_ahead ("defstate_shift <- empty string");
+ print_lookahead ("defstate_shift <- empty string");
}
;
static int
yylex (void)
{
- static char const *input = "abcdddd";
- static int i = 0;
+ static char const input[] = "abcdddd";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
yylloc.first_line = yylloc.last_line = 1;
- yylloc.first_column = yylloc.last_column = i + 1;
- yylval.value = input[i] + 'A' - 'a';
- return input[i++];
+ yylloc.first_column = yylloc.last_column = toknum + 1;
+ yylval.value = input[toknum] + 'A' - 'a';
+ return input[toknum++];
}
static void
-print_look_ahead (char const *reduction)
+print_lookahead (char const *reduction)
{
printf ("%s:\n yychar=", reduction);
if (yychar == YYEMPTY)
}
]])
-AT_CHECK([[bison -o glr-regr14.c glr-regr14.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr14.c glr-regr14.y]], 0, [],
[glr-regr14.y: conflicts: 3 reduce/reduce
])
AT_COMPILE([glr-regr14])
-AT_CHECK([[./glr-regr14]], 0,
+AT_PARSER_CHECK([[./glr-regr14]], 0,
[conflict <- empty string:
yychar='a', yylval='A', yylloc=(1,1),(1,1)
defstate_look <- empty string:
static int
yylex (void)
{
+ static int called;
+ if (called++)
+ abort ();
return 0;
}
}
]])
-AT_CHECK([[bison -o glr-regr15.c glr-regr15.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr15.c glr-regr15.y]], 0, [],
[glr-regr15.y: conflicts: 2 reduce/reduce
])
AT_COMPILE([glr-regr15])
-AT_CHECK([[./glr-regr15]], 0, [],
+AT_PARSER_CHECK([[./glr-regr15]], 0, [],
[syntax is ambiguous
])
static int
yylex (void)
{
- static const char *input = "ab";
- if (*input == 'b')
+ static char const input[] = "ab";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
+ if (input[toknum] == 'b')
lookahead_value = 1;
- return *input++;
+ return input[toknum++];
}
int
}
]])
-AT_CHECK([[bison -o glr-regr16.c glr-regr16.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr16.c glr-regr16.y]], 0, [],
[glr-regr16.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr16])
-AT_CHECK([[./glr-regr16]], 0, [],
+AT_PARSER_CHECK([[./glr-regr16]], 0, [],
[syntax error
])
[[
%glr-parser
%locations
-%pure-parser
+%define api.pure
%error-verbose
%union { int dummy; }
%%
+/* Tests the case of an empty RHS that has inherited the location of the
+ previous nonterminal, which is unresolved. That location is reported as the
+ last position of the ambiguity. */
+start: ambig1 empty1 | ambig2 empty2 ;
+
/* Tests multiple levels of yyresolveLocations recursion. */
-start: ambig1 | ambig2 ;
ambig1: sub_ambig1 | sub_ambig2 ;
ambig2: sub_ambig1 | sub_ambig2 ;
-/* Tests non-empty RHS as well as empty RHS with either initial location or
- location of previous token. Both empty RHS locations are printed in the
- error message. */
-sub_ambig1: empty 'a' 'b' empty ;
-sub_ambig2: empty 'a' 'b' empty ;
-empty: ;
+/* Tests the case of a non-empty RHS as well as the case of an empty RHS that
+ has inherited the initial location. The empty RHS's location is reported as
+ the first position in the ambiguity. */
+sub_ambig1: empty1 'a' 'b' ;
+sub_ambig2: empty2 'a' 'b' ;
+empty1: ;
+empty2: ;
%%
static void
yyerror (YYLTYPE *locp, char const *msg)
{
- fprintf (stderr, "Error at %d.%d-%d.%d: %s.\n", locp->first_line,
- locp->first_column, locp->last_line, locp->last_column, msg);
+ fprintf (stderr, "%d.%d-%d.%d: %s.\n", locp->first_line,
+ locp->first_column, locp->last_line, locp->last_column, msg);
}
-/*ARGSUSED*/ static int
+static int
yylex (YYSTYPE *lvalp, YYLTYPE *llocp)
{
- static const char input[] = "ab";
- static const char *inputp = input;
+ static char const input[] = "ab";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
+ lvalp->dummy = 0;
llocp->first_line = llocp->last_line = 2;
- llocp->first_column = inputp - input + 1;
+ llocp->first_column = toknum + 1;
llocp->last_column = llocp->first_column + 1;
- return *inputp++;
+ return input[toknum++];
}
int
}
]])
-AT_CHECK([[bison -o glr-regr17.c glr-regr17.y]], 0, [],
+AT_BISON_CHECK([[-o glr-regr17.c glr-regr17.y]], 0, [],
[glr-regr17.y: conflicts: 3 reduce/reduce
])
AT_COMPILE([glr-regr17])
-AT_CHECK([[./glr-regr17]], 0, [],
-[Error at 1.1-2.3: syntax is ambiguous.
+AT_PARSER_CHECK([[./glr-regr17]], 0, [],
+[1.1-2.3: syntax is ambiguous.
+])
+
+AT_CLEANUP
+
+
+## -------------------------------------------------------------##
+## Missed %merge type warnings when LHS type is declared later. ##
+## -------------------------------------------------------------##
+
+AT_SETUP([Missed %merge type warnings when LHS type is declared later])
+AT_DATA_GRAMMAR([glr-regr18.y],
+[[%glr-parser
+
+%{
+ #include <stdlib.h>
+ static void yyerror (char const *);
+ static int yylex ();
+%}
+
+%union {
+ int type1;
+ int type2;
+ int type3;
+}
+
+%%
+
+sym1: sym2 %merge<merge> { $$ = $1; } ;
+sym2: sym3 %merge<merge> { $$ = $1; } ;
+sym3: %merge<merge> { $$ = 0; } ;
+
+%type <type1> sym1;
+%type <type2> sym2;
+%type <type3> sym3;
+
+%%
+
+static void
+yyerror (char const *msg)
+{
+ fprintf (stderr, "%s\n", msg);
+}
+
+static int
+yylex ()
+{
+ static int called;
+ if (called++)
+ abort ();
+ return 0;
+}
+
+int
+main (void)
+{
+ return yyparse ();
+}
+]])
+
+AT_BISON_CHECK([[-o glr-regr18.c glr-regr18.y]], 1, [],
+[glr-regr18.y:26.18-24: result type clash on merge function 'merge': <type2> != <type1>
+glr-regr18.y:25.18-24: previous declaration
+glr-regr18.y:27.13-19: result type clash on merge function 'merge': <type3> != <type2>
+glr-regr18.y:26.18-24: previous declaration
+])
+
+AT_CLEANUP
+
+
+## ------------------- ##
+## Ambiguity reports. ##
+## ------------------- ##
+
+AT_SETUP([Ambiguity reports])
+
+AT_DATA_GRAMMAR([input.y],
+[[
+%{
+ #include <stdio.h>
+ #include <stdlib.h>
+ static void yyerror (char const *);
+ static int yylex (void);
+%}
+
+%debug
+%glr-parser
+
+%%
+start:
+ 'a' b 'c' d
+| 'a' b 'c' d
+;
+b: 'b';
+d: /* nada. */;
+%%
+
+static int
+yylex (void)
+{
+ static char const input[] = "abc";
+ static size_t toknum;
+ if (! (toknum < sizeof input))
+ abort ();
+ return input[toknum++];
+}
+
+static void
+yyerror (char const *msg)
+{
+ fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+ yydebug = 1;
+ return !!yyparse ();
+}
+]])
+
+AT_BISON_CHECK([[-o input.c input.y]], 0, [],
+[input.y: conflicts: 1 reduce/reduce
+])
+AT_COMPILE([input])
+
+AT_PARSER_CHECK([[./input]], 1, [],
+[Starting parse
+Entering state 0
+Reading a token: Next token is token 'a' ()
+Shifting token 'a' ()
+Entering state 1
+Reading a token: Next token is token 'b' ()
+Shifting token 'b' ()
+Entering state 3
+Reducing stack 0 by rule 3 (line 25):
+ $1 = token 'b' ()
+-> $$ = nterm b ()
+Entering state 4
+Reading a token: Next token is token 'c' ()
+Shifting token 'c' ()
+Entering state 6
+Reducing stack 0 by rule 4 (line 26):
+-> $$ = nterm d ()
+Entering state 7
+Reading a token: Now at end of input.
+Stack 0 Entering state 7
+Now at end of input.
+Splitting off stack 1 from 0.
+Reduced stack 1 by rule #2; action deferred. Now in state 2.
+Stack 1 Entering state 2
+Now at end of input.
+Reduced stack 0 by rule #1; action deferred. Now in state 2.
+Merging stack 0 into stack 1.
+Stack 1 Entering state 2
+Now at end of input.
+Removing dead stacks.
+Rename stack 1 -> 0.
+On stack 0, shifting token $end ()
+Stack 0 now in state #5
+Ambiguity detected.
+Option 1,
+ start -> <Rule 1, tokens 1 .. 3>
+ 'a' <tokens 1 .. 1>
+ b <tokens 2 .. 2>
+ 'c' <tokens 3 .. 3>
+ d <empty>
+
+Option 2,
+ start -> <Rule 2, tokens 1 .. 3>
+ 'a' <tokens 1 .. 1>
+ b <tokens 2 .. 2>
+ 'c' <tokens 3 .. 3>
+ d <empty>
+
+syntax is ambiguous
+Cleanup: popping token $end ()
+Cleanup: popping unresolved nterm start ()
+Cleanup: popping nterm d ()
+Cleanup: popping token 'c' ()
+Cleanup: popping nterm b ()
+Cleanup: popping token 'a' ()
])
AT_CLEANUP