[bison.git] / tests / glr-regression.at

# 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.

# 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([[GLR Regression Tests]])

## --------------------------- ##
## Badly Collapsed GLR States. ##
## --------------------------- ##

AT_SETUP([Badly Collapsed GLR States])

AT_DATA_GRAMMAR([glr-regr1.y],
[[/* Regression Test: Improper state compression */
/* Reported by Scott McPeak */

%{
#include <stdio.h>

#define YYSTYPE int
static YYSTYPE exprMerge (YYSTYPE x0, YYSTYPE x1);
int yylex (void);
void yyerror (char const *msg);
%}


%glr-parser


/* -------- productions ------ */
%%

StartSymbol: E  { $$=0; }                   %merge <exprMerge>
           ;

E: E 'P' E { $$=1; printf("E -> E 'P' E\n"); }  %merge <exprMerge>
 | 'B'     { $$=2; printf("E -> 'B'\n"); }      %merge <exprMerge>
 ;


/* ---------- C code ----------- */
%%

static YYSTYPE exprMerge (YYSTYPE x0, YYSTYPE x1)
{
  (void) x0;
  (void) x1;
  printf ("<OR>\n");
  return 0;
}

int
main (void)
{
  return yyparse ();
}

void
yyerror (char const *msg)
{
  fprintf (stderr, "%s\n", msg);
}


int
yylex (void)
{
  for (;;)
    {
      int ch = getchar ();
      if (ch == EOF)
	return 0;
      else if (ch == 'B' || ch == 'P')
	return ch;
    }
}
]])

AT_CHECK([[bison -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,
[[E -> 'B'
E -> 'B'
E -> E 'P' E
E -> 'B'
E -> E 'P' E
E -> 'B'
E -> E 'P' E
E -> E 'P' E
<OR>
]], [])

AT_CLEANUP

## ------------------------------------------------------------ ##
## Improper handling of embedded actions and $-N in GLR parsers ##
## ------------------------------------------------------------ ##

AT_SETUP([Improper handling of embedded actions and dollar(-N) in GLR parsers])

AT_DATA_GRAMMAR([glr-regr2a.y],
[[/* Regression Test: Improper handling of embedded actions and $-N  */
/* Reported by S. Eken */

%{
  #define YYSTYPE char *

  #include <ctype.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  int yylex (void);
  void yyerror (char const *);
%}

%glr-parser

%%

command:
    's' var 't'
       { printf ("Variable: '%s'\n", $2); }
    'v' 'x' 'q'
       { free ($2); }
  | 's' var_list 't' 'e'
       { printf ("Varlist: '%s'\n", $2); free ($2); }
  | 's' var 't' var_printer 'x'
       { free ($2); }
  ;

var:
  'V'
     { $$ = $1; }
  ;

var_list:
  var
    { $$ = $1; }
  | var ',' var_list
    {
      char *s = (char *) realloc ($1, strlen ($1) + 1 + strlen ($3) + 1);
      strcat (s, ",");
      strcat (s, $3);
      free ($3);
      $$ = s;
    }
  ;

var_printer: 'v'
   { printf ("Variable: '%s'\n", $-1); }

%%

FILE *input = NULL;

int
yylex (void)
{
  char buf[50];
  char *s;
  switch (fscanf (input, " %1[a-z,]", buf)) {
  case 1:
    return buf[0];
  case EOF:
    return 0;
  default:
    break;
  }
  if (fscanf (input, "%49s", buf) != 1)
    return 0;
  if (sizeof buf - 1 <= strlen (buf))
    abort ();
  s = (char *) malloc (strlen (buf) + 1);
  strcpy (s, buf);
  yylval = s;
  return 'V';
}

void
yyerror (char const *s)
{ printf ("%s\n", s);
}

int
main (int argc, char **argv)
{
  input = stdin;
  if (argc == 2 && !(input = fopen (argv[1], "r"))) return 3;
  return yyparse ();
}
]])

AT_CHECK([[bison -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,
[[Variable: 'VARIABLE_1'
]], [])
AT_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,
[[Variable: 'VARIABLE_3'
]], [])


AT_CLEANUP

## ------------------------------------------------------------ ##
## Improper merging of GLR delayed action sets                  ##
## ------------------------------------------------------------ ##

AT_SETUP([Improper merging of GLR delayed action sets])

AT_DATA_GRAMMAR([glr-regr3.y],
[[/* Regression Test: Improper merging of GLR delayed action sets.  */
/* Reported by M. Rosien */

%{
#include <stdio.h>
#include <stdarg.h>

static int MergeRule (int x0, int x1);
static void yyerror(char const * s);
int yylex (void);

#define RULE(x) (1 << (x))

%}

%glr-parser

%token BAD_CHAR
%token P1 P2 T1 T2 T3 T4 O1 O2

%%

S : P1 T4 O2 NT6 P2  { printf ("Result: %x\n", $4); }
;

NT1 : P1 T1 O1 T2 P2 { $$ = RULE(2); }  %merge<MergeRule>
;

NT2 : NT1             { $$ = RULE(3); } %merge<MergeRule>
    | P1 NT1 O1 T3 P2 { $$ = RULE(4); } %merge<MergeRule>
;

NT3 : T3              { $$ = RULE(5); } %merge<MergeRule>
    | P1 NT1 O1 T3 P2 { $$ = RULE(6); } %merge<MergeRule>
;

NT4 : NT3              { $$ = RULE(7); } %merge<MergeRule>
    | NT2              { $$ = RULE(8); } %merge<MergeRule>
    | P1 NT2 O1 NT3 P2 { $$ = RULE(9); } %merge<MergeRule>
;

NT5 : NT4              { $$ = RULE(10); } %merge<MergeRule>
;

NT6 : P1 NT1 O1 T3 P2  { $$ = RULE(11) | $2; } %merge<MergeRule>
    | NT5              { $$ = RULE(12) | $1; } %merge<MergeRule>
;

%%

static int MergeRule (int x0, int x1) {
  return x0 | x1;
}

static void yyerror(char const * s) {
  fprintf(stderr,"error: %s\n",s);
}

FILE *input = NULL;

int P[] = { P1, P2 };
int O[] = { O1, O2 };
int T[] = { T1, T2, T3, T4 };

int yylex (void)
{
  char inp[3];
  if (fscanf (input, "%2s", inp) == EOF)
    return 0;
  switch (inp[0])
    {
    case 'p': return P[inp[1] - '1'];
    case 't': return T[inp[1] - '1'];
    case 'o': return O[inp[1] - '1'];
    }
  return BAD_CHAR;
}

int main(int argc, char* argv[]) {
  input = stdin;
  if (argc == 2 && !(input = fopen (argv[1], "r"))) return 3;
  return yyparse ();
}
]])

AT_CHECK([[bison -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,
[[Result: 1c04
]], [])

AT_CLEANUP


## ------------------------------------------------------------------------- ##
## Duplicate representation of merged trees.  See			     ##
## <http://lists.gnu.org/archive/html/help-bison/2005-07/msg00013.html>.     ##
## ------------------------------------------------------------------------- ##

AT_SETUP([Duplicate representation of merged trees])

AT_DATA_GRAMMAR([glr-regr4.y],
[[
%union { char *ptr; }
%type <ptr> S A A1 A2 B
%glr-parser

%{
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  static char *merge (YYSTYPE, YYSTYPE);
  static char *make_value (char const *, char const *);
  static void yyerror (char const *);
  static int yylex (void);
%}

%%

tree: S { printf ("%s\n", $1); } ;

S:
  A   %merge<merge> { $$ = make_value ("S", $1); }
  | B %merge<merge> { $$ = make_value ("S", $1); }
  ;

A:
  A1   %merge<merge> { $$ = make_value ("A", $1); }
  | A2 %merge<merge> { $$ = make_value ("A", $1); }
  ;

A1: 'a' { $$ = make_value ("A1", "'a'"); } ;
A2: 'a' { $$ = make_value ("A2", "'a'"); } ;
B:  'a' { $$ = make_value ("B", "'a'");  } ;

%%

static int
yylex (void)
{
  static char const *input = "a";
  return *input++;
}

int
main (void)
{
  return yyparse ();
}

static char *
make_value (char const *parent, char const *child)
{
  char const format[] = "%s <- %s";
  char *value =
    (char *) malloc (strlen (parent) + strlen (child) + sizeof format);
  sprintf (value, format, parent, child);
  return value;
}

static char *
merge (YYSTYPE s1, YYSTYPE s2)
{
  char const format[] = "merge{ %s and %s }";
  char *value =
    (char *) malloc (strlen (s1.ptr) + strlen (s2.ptr) + sizeof format);
  sprintf (value, format, s1.ptr, s2.ptr);
  return value;
}

static void
yyerror (char const *msg)
{
  fprintf (stderr, "%s\n", msg);
}
]])

AT_CHECK([[bison -o glr-regr4.c glr-regr4.y]], 0, [],
[glr-regr4.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr4])

AT_CHECK([[./glr-regr4]], 0,
[[merge{ S <- merge{ A <- A1 <- 'a' and A <- A2 <- 'a' } and S <- B <- 'a' }
]], [])

AT_CLEANUP


## -------------------------------------------------------------------------- ##
## User destructor for unresolved GLR semantic value.  See		      ##
## <http://lists.gnu.org/archive/html/bison-patches/2005-08/msg00016.html>.   ##
## -------------------------------------------------------------------------- ##

AT_SETUP([User destructor for unresolved GLR semantic value])

AT_DATA_GRAMMAR([glr-regr5.y],
[[
%{
  #include <stdio.h>
  #include <stdlib.h>
  static void yyerror (char const *);
  static int yylex (void);
  enum { MAGIC_VALUE = -1057808125 }; /* originally chosen at random */
%}

%glr-parser
%union { int value; }
%type <value> start

%destructor {
  if ($$ != MAGIC_VALUE)
    {
      fprintf (stderr, "Bad destructor call.\n");
      exit (EXIT_FAILURE);
    }
} start

%%

start:
   'a' { $$ = MAGIC_VALUE; }
   | 'a' { $$ = MAGIC_VALUE; }
   ;

%%

static int
yylex (void)
{
  static char const *input = "a";
  return *input++;
}

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

int
main (void)
{
  return yyparse () != 1;
}
]])

AT_CHECK([[bison -o glr-regr5.c glr-regr5.y]], 0, [],
[glr-regr5.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr5])

AT_CHECK([[./glr-regr5]], 0, [],
[syntax is ambiguous
])

AT_CLEANUP


## -------------------------------------------------------------------------- ##
## User destructor after an error during a split parse.  See		      ##
## <http://lists.gnu.org/archive/html/bison-patches/2005-08/msg00029.html>.   ##
## -------------------------------------------------------------------------- ##

AT_SETUP([User destructor after an error during a split parse])

AT_DATA_GRAMMAR([glr-regr6.y],
[[
%{
  #include <stdio.h>
  #include <stdlib.h>
  static void yyerror (char const *);
  static int yylex (void);
%}

%glr-parser
%union { int value; }
%type <value> 'a'

%destructor {
  printf ("Destructor called.\n");
} 'a'

%%

start: 'a' | 'a' ;

%%

static int
yylex (void)
{
  static char const *input = "a";
  return *input++;
}

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

int
main (void)
{
  return yyparse () != 1;
}
]])

AT_CHECK([[bison -o glr-regr6.c glr-regr6.y]], 0, [],
[glr-regr6.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr6])

AT_CHECK([[./glr-regr6]], 0,
[Destructor called.
],
[syntax is ambiguous
])

AT_CLEANUP


## ------------------------------------------------------------------------- ##
## Duplicated user destructor for lookahead.  See			     ##
## <http://lists.gnu.org/archive/html/bison-patches/2005-08/msg00035.html>.  ##
## ------------------------------------------------------------------------- ##

AT_SETUP([Duplicated user destructor for lookahead])

AT_DATA_GRAMMAR([glr-regr7.y],
[[
%{
  #include <stdio.h>
  #include <stdlib.h>
  static void yyerror (char const *);
  static int yylex (void);
  #define YYSTACKEXPANDABLE 0
%}

%glr-parser
%union { int *count; }
%type <count> 'a'

%destructor {
  if ((*$$)++)
    fprintf (stderr, "Destructor called on same value twice.\n");
} 'a'

%%

start:
    stack1 start
  | stack2 start
  | /* empty */
  ;
stack1: 'a' ;
stack2: 'a' ;

%%

static int
yylex (void)
{
  yylval.count = (int *) malloc (sizeof (int));
  if (!yylval.count)
    {
      fprintf (stderr, "Test inconclusive.\n");
      exit (EXIT_FAILURE);
    }
  *yylval.count = 0;
  return 'a';
}

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

int
main (void)
{
  return yyparse ();
}
]])

AT_CHECK([[bison -o glr-regr7.c glr-regr7.y]], 0, [],
[glr-regr7.y: conflicts: 2 reduce/reduce
])
AT_COMPILE([glr-regr7])

AT_CHECK([[./glr-regr7]], 2, [],
[memory exhausted
])

AT_CLEANUP


## ------------------------------------------------------------------------- ##
## Incorrect default location for empty right-hand sides.  Adapted from bug  ##
## report by Claudia Hermann.						     ##
## See http://lists.gnu.org/archive/html/bug-bison/2005-10/msg00069.html and ##
## http://lists.gnu.org/archive/html/bug-bison/2005-10/msg00072.html         ##
## ------------------------------------------------------------------------- ##

AT_SETUP([Incorrectly initialized location for empty right-hand side in GLR])

AT_DATA_GRAMMAR([glr-regr8.y],
[[
%{
  #include <stdio.h>
  #include <stdlib.h>
  static void yyerror (char const *);
  static int yylex (void);
  static void yyerror(const char *msg);
%}

%token T_CONSTANT
%token T_PORT
%token T_SIGNAL

%glr-parser

%%


PortClause	: T_PORT InterfaceDeclaration T_PORT
		{ printf("%d/%d - %d/%d - %d/%d\n",
			 @1.first_column, @1.last_column,
			 @2.first_column, @2.last_column,
			 @3.first_column, @3.last_column); }
	;

InterfaceDeclaration	: OptConstantWord	%dprec 1
	| OptSignalWord	%dprec 2
	;

OptConstantWord	: /* empty */
	| T_CONSTANT
	;

OptSignalWord	: /* empty */
		{ printf("empty: %d/%d\n", @$.first_column, @$.last_column); }
	| T_SIGNAL
	;

%%

void yyerror(const char *msg)
{
  fprintf (stderr, "error\n");
}

static int lexIndex;

int yylex (void)
{
  lexIndex += 1;
  switch (lexIndex)
    {
    case 1:
      yylloc.first_column = 1;
      yylloc.last_column = 9;
      return T_PORT;
    case 2:
      yylloc.first_column = 13;
      yylloc.last_column = 17;
      return T_PORT;
    default:
      return 0;
    }
}

int
main (void)
{
  yyparse();
  return 0;
}
]])

AT_CHECK([[bison -o glr-regr8.c glr-regr8.y]], 0, [],
[glr-regr8.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr8])

AT_CHECK([[./glr-regr8]], 0,
[empty: 9/9
1/9 - 9/9 - 13/17
],
[])

AT_CLEANUP


## ------------------------------------------------------------------------- ##
## No users destructors if stack 0 deleted.  See			     ##
## <http://lists.gnu.org/archive/html/bison-patches/2005-09/msg00109.html>.  ##
## ------------------------------------------------------------------------- ##

AT_SETUP([No users destructors if stack 0 deleted])

AT_DATA_GRAMMAR([glr-regr9.y],
[[
%{
# include <stdio.h>
# include <stdlib.h>
  static void yyerror (char const *);
  static int yylex (void);
# define YYSTACKEXPANDABLE 0
  static int tokens = 0;
  static int destructors = 0;
# define USE(Var)
%}

%glr-parser
%union { int dummy; }
%type <dummy> 'a'

%destructor {
  destructors += 1;
} 'a'

%%

start:
    ambig0 'a'   { destructors += 2; USE ($2); }
  | ambig1 start { destructors += 1; }
  | ambig2 start { destructors += 1; }
  ;

ambig0: 'a' ;
ambig1: 'a' ;
ambig2: 'a' ;

%%

static int
yylex (void)
{
  tokens += 1;
  return 'a';
}

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

int
main (void)
{
  int exit_status;
  exit_status = yyparse ();
  if (tokens != destructors)
    {
      fprintf (stderr, "Tokens = %d, Destructors = %d\n", tokens, destructors);
      return 1;
    }
  return !exit_status;
}
]])

AT_CHECK([[bison -o glr-regr9.c glr-regr9.y]], 0, [],
[glr-regr9.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr9])

AT_CHECK([[./glr-regr9]], 0, [],
[memory exhausted
])

AT_CLEANUP


## ------------------------------------------------------------------------- ##
## Corrupted semantic options if user action cuts parse.	             ##
## ------------------------------------------------------------------------- ##

AT_SETUP([Corrupted semantic options if user action cuts parse])

AT_DATA_GRAMMAR([glr-regr10.y],
[[
%{
# include <stdio.h>
  static void yyerror (char const *);
  static int yylex (void);
  #define GARBAGE_SIZE 50
  static char garbage[GARBAGE_SIZE];
%}

%glr-parser
%union { char *ptr; }
%type <ptr> start

%%

start:
    %dprec 2 { $$ = garbage; YYACCEPT; }
  | %dprec 1 { $$ = garbage; YYACCEPT; }
  ;

%%

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

static int
yylex (void)
{
  return 0;
}

int
main (void)
{
  int index;
  for (index = 0; index < GARBAGE_SIZE; index+=1)
    garbage[index] = 108;
  return yyparse ();
}
]])

AT_CHECK([[bison -t -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_CLEANUP


## ------------------------------------------------------------------------- ##
## Undesirable destructors if user action cuts parse.			     ##
## ------------------------------------------------------------------------- ##

AT_SETUP([Undesirable destructors if user action cuts parse])

AT_DATA_GRAMMAR([glr-regr11.y],
[[
%{
# include <stdlib.h>
  static void yyerror (char const *);
  static int yylex (void);
  static int destructors = 0;
# define USE(val)
%}

%glr-parser
%union { int dummy; }
%type <int> 'a'
%destructor { destructors += 1; } 'a'

%%

start:
    'a' %dprec 2 { USE ($1); destructors += 1; YYACCEPT; }
  | 'a' %dprec 1 { USE ($1); destructors += 1; YYACCEPT; }
  ;

%%

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

static int
yylex (void)
{
  static char const *input = "a";
  return *input++;
}

int
main (void)
{
  int exit_status = yyparse ();
  if (destructors != 1)
    {
      fprintf (stderr, "Destructor calls: %d\n", destructors);
      return 1;
    }
  return exit_status;
}
]])

AT_CHECK([[bison -t -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_CLEANUP


## ------------------------------------------------------------------------- ##
## Leaked merged semantic value if user action cuts parse.		     ##
## ------------------------------------------------------------------------- ##

AT_SETUP([Leaked merged semantic value if user action cuts parse])

AT_DATA_GRAMMAR([glr-regr12.y],
[[
%glr-parser
%union { int dummy; }
%type <dummy> start
%destructor { has_value = 0; } start

%{
# include <stdlib.h>
  static int merge (YYSTYPE, YYSTYPE);
  static void yyerror (char const *);
  static int yylex (void);
  static int has_value = 0;
# define USE(val)
%}

%%

start:
    %merge<merge> { has_value = 1; USE ($$); }
  | %merge<merge> { USE ($$); YYACCEPT; }
  ;

%%

static int
merge (YYSTYPE s1, YYSTYPE s2)
{
  /* Not invoked. */
  char dummy = s1.dummy + s2.dummy;
  return dummy;
}

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

static int
yylex (void)
{
  return 0;
}

int
main (void)
{
  int exit_status = yyparse ();
  if (has_value)
    {
      fprintf (stderr, "Destructor not called.\n");
      return 1;
    }
  return exit_status;
}
]])

AT_CHECK([[bison -t -o glr-regr12.c glr-regr12.y]], 0, [],
[glr-regr12.y: conflicts: 1 reduce/reduce
])
AT_COMPILE([glr-regr12])

AT_CHECK([[./glr-regr12]], 0, [], [])

AT_CLEANUP


## ------------------------------------------------------------------------- ##
## Incorrect lookahead during deterministic GLR.  See			     ##
## <http://lists.gnu.org/archive/html/help-bison/2005-07/msg00017.html>.     ##
## ------------------------------------------------------------------------- ##

AT_SETUP([Incorrect lookahead during deterministic GLR])

AT_DATA_GRAMMAR([glr-regr13.y],
[[
/* Tests:
     - Defaulted state with initial yychar: yychar == YYEMPTY.
     - Nondefaulted state: yychar != YYEMPTY.
     - Defaulted state after lookahead: yychar != YYEMPTY.
     - Defaulted state after shift: yychar == YYEMPTY.  */

%{
  #include <stdio.h>
  static void yyerror (char const *);
  static int yylex (void);
  static void print_look_ahead (char const *);
  #define USE(value)
%}

%union { char value; }
%type <value> 'a' 'b'
%glr-parser
%locations

%%

start:
  defstate_init defstate_shift 'b' {
    USE ($3);
    print_look_ahead ("start <- defstate_init defstate_shift 'b'");
  }
  ;
defstate_init:
  {
    print_look_ahead ("defstate_init <- empty string");
  }
  ;
defstate_shift:
  nondefstate defstate_look 'a' {
    USE ($3);
    print_look_ahead ("defstate_shift <- nondefstate defstate_look 'a'");
  }
  ;
defstate_look:
  {
    print_look_ahead ("defstate_look <- empty string");
  }
  ;
nondefstate:
  {
    print_look_ahead ("nondefstate <- empty string");
  }
  | 'b' {
    USE ($1);
    print_look_ahead ("nondefstate <- 'b'");
  }
  ;

%%

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

static int
yylex (void)
{
  static char const *input = "ab";
  static int index = 0;
  yylloc.first_line = yylloc.last_line = 1;
  yylloc.first_column = yylloc.last_column = index+1;
  yylval.value = input[index] + 'A' - 'a';
  return input[index++];
}

static void
print_look_ahead (char const *reduction)
{
  printf ("%s:\n  yychar=", reduction);
  if (yychar == YYEMPTY)
    printf ("YYEMPTY");
  else if (yychar == YYEOF)
    printf ("YYEOF");
  else
    {
      printf ("'%c', yylval='", yychar);
      if (yylval.value > ' ')
	printf ("%c", yylval.value);
      printf ("', yylloc=(%d,%d),(%d,%d)",
	      yylloc.first_line, yylloc.first_column,
	      yylloc.last_line, yylloc.last_column);
    }
  printf ("\n");
}

int
main (void)
{
  yychar = '#'; /* Not a token in the grammar.  */
  yylval.value = '!';
  return yyparse ();
}
]])

AT_CHECK([[bison -t -o glr-regr13.c glr-regr13.y]], 0, [], [])
AT_COMPILE([glr-regr13])

AT_CHECK([[./glr-regr13]], 0,
[defstate_init <- empty string:
  yychar=YYEMPTY
nondefstate <- empty string:
  yychar='a', yylval='A', yylloc=(1,1),(1,1)
defstate_look <- empty string:
  yychar='a', yylval='A', yylloc=(1,1),(1,1)
defstate_shift <- nondefstate defstate_look 'a':
  yychar=YYEMPTY
start <- defstate_init defstate_shift 'b':
  yychar=YYEMPTY
], [])

AT_CLEANUP


## ------------------------------------------------------------------------- ##
## Incorrect lookahead during nondeterministic GLR.			     ##
## ------------------------------------------------------------------------- ##

AT_SETUP([Incorrect lookahead during nondeterministic GLR])

AT_DATA_GRAMMAR([glr-regr14.y],
[[
/* Tests:
     - Conflicting actions (split-off parse, which copies lookahead need,
       which is necessarily yytrue) and nonconflicting actions (non-split-off
       parse) for nondefaulted state: yychar != YYEMPTY.
     - Merged deferred actions (lookahead need and RHS from different stack
       than the target state) and nonmerged deferred actions (same stack).
     - Defaulted state after lookahead: yychar != YYEMPTY.
     - Defaulted state after shift: yychar == YYEMPTY.
     - yychar != YYEMPTY but lookahead need is yyfalse (a previous stack has
       seen the lookahead but current stack has not).
     - Exceeding stack capacity (stack explosion), and thus reallocating
       lookahead need array.
   Note that it does not seem possible to see the initial yychar value during
   nondeterministic operation since:
     - In order to preserve the initial yychar, only defaulted states may be
       entered.
     - If only defaulted states are entered, there are no conflicts, so
       nondeterministic operation does not start.  */

%union { char value; }

%{
  #include <stdio.h>
  static void yyerror (char const *);
  static int yylex (void);
  static void print_look_ahead (char const *);
  static char merge (union YYSTYPE, union YYSTYPE);
  #define USE(value)
%}

%type <value> 'a' 'b' 'c' 'd' stack_explosion
%glr-parser
%locations

%%

start:
  merge 'c' stack_explosion {
    USE ($2); USE ($3);
    print_look_ahead ("start <- merge 'c' stack_explosion");
  }
  ;

/* When merging the 2 deferred actions, the lookahead needs are different.  */
merge:
  nonconflict1 'a' 'b' nonconflict2 %dprec 1 {
    USE ($2); USE ($3);
    print_look_ahead ("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'"
		      " defstate_shift");
  }
  ;

nonconflict1:
  {
    print_look_ahead ("nonconflict1 <- empty string");
  }
  ;
nonconflict2:
  {
    print_look_ahead ("nonconflict2 <- empty string");
  }
  | 'a' {
    USE ($1);
    print_look_ahead ("nonconflict2 <- 'a'");
  }
  ;
conflict:
  {
    print_look_ahead ("conflict <- empty string");
  }
  ;
defstate_look:
  {
    print_look_ahead ("defstate_look <- empty string");
  }
  ;

/* yychar != YYEMPTY but lookahead need is yyfalse.  */
defstate_shift:
  {
    print_look_ahead ("defstate_shift <- empty string");
  }
  ;

stack_explosion:
  { $$ = '\0'; }
  | alt1 stack_explosion %merge<merge> { $$ = $2; }
  | alt2 stack_explosion %merge<merge> { $$ = $2; }
  | alt3 stack_explosion %merge<merge> { $$ = $2; }
  ;
alt1:
  'd' no_look {
    USE ($1);
    if (yychar != 'd' && yychar != YYEOF)
      {
	fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
      }
  }
  ;
alt2:
  'd' no_look {
    USE ($1);
    if (yychar != 'd' && yychar != YYEOF)
      {
	fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
      }
  }
  ;
alt3:
  'd' no_look {
    USE ($1);
    if (yychar != 'd' && yychar != YYEOF)
      {
	fprintf (stderr, "Incorrect lookahead during stack explosion.\n");
      }
  }
  ;
no_look:
  {
    if (yychar != YYEMPTY)
      {
	fprintf (stderr,
		 "Found lookahead where shouldn't during stack explosion.\n");
      }
  }
  ;

%%

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

static int
yylex (void)
{
  static char const *input = "abcdddd";
  static int index = 0;
  yylloc.first_line = yylloc.last_line = 1;
  yylloc.first_column = yylloc.last_column = index+1;
  yylval.value = input[index] + 'A' - 'a';
  return input[index++];
}

static void
print_look_ahead (char const *reduction)
{
  printf ("%s:\n  yychar=", reduction);
  if (yychar == YYEMPTY)
    printf ("YYEMPTY");
  else if (yychar == YYEOF)
    printf ("YYEOF");
  else
    {
      printf ("'%c', yylval='", yychar);
      if (yylval.value > ' ')
	printf ("%c", yylval.value);
      printf ("', yylloc=(%d,%d),(%d,%d)",
	      yylloc.first_line, yylloc.first_column,
	      yylloc.last_line, yylloc.last_column);
    }
  printf ("\n");
}

static char
merge (union YYSTYPE s1, union YYSTYPE s2)
{
  char dummy = s1.value + s2.value;
  return dummy;
}

int
main (void)
{
  yychar = '#'; /* Not a token in the grammar.  */
  yylval.value = '!';
  return yyparse ();
}
]])

AT_CHECK([[bison -t -o glr-regr14.c glr-regr14.y]], 0, [],
[glr-regr14.y: conflicts: 3 reduce/reduce
])
AT_COMPILE([glr-regr14])

AT_CHECK([[./glr-regr14]], 0,
[conflict <- empty string:
  yychar='a', yylval='A', yylloc=(1,1),(1,1)
defstate_look <- empty string:
  yychar='a', yylval='A', yylloc=(1,1),(1,1)
nonconflict2 <- empty string:
  yychar='b', yylval='B', yylloc=(1,2),(1,2)
defstate_shift <- empty string:
  yychar=YYEMPTY
merge <- conflict defstate_look 'a' nonconflict2 'b' defstate_shift:
  yychar=YYEMPTY
start <- merge 'c' stack_explosion:
  yychar=YYEOF
], [])

AT_CLEANUP