# 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 #define YYSTYPE int static YYSTYPE exprMerge (YYSTYPE x0, YYSTYPE x1); int yylex (void); void yyerror (char const *msg); %} %glr-parser /* -------- productions ------ */ %% StartSymbol: E { $$=0; } %merge ; E: E 'P' E { $$=1; printf("E -> E 'P' E\n"); } %merge | 'B' { $$=2; printf("E -> 'B'\n"); } %merge ; /* ---------- C code ----------- */ %% static YYSTYPE exprMerge (YYSTYPE x0, YYSTYPE x1) { (void) x0; (void) x1; printf ("\n"); return 0; } int main (void) { return yyparse (); } void yyerror (char const *msg) { fprintf (stderr, "%s\n", msg); } int yylex (void) { for (;;) { int ch = getchar (); if (ch == EOF) return 0; else if (ch == 'B' || ch == 'P') return ch; } } ]]) AT_CHECK([[bison -o glr-regr1.c glr-regr1.y]], 0, [], [glr-regr1.y: conflicts: 1 shift/reduce ]) AT_COMPILE([glr-regr1]) AT_CHECK([[echo BPBPB | ./glr-regr1]], 0, [[E -> 'B' E -> 'B' E -> E 'P' E E -> 'B' E -> E 'P' E E -> 'B' E -> E 'P' E E -> E 'P' E ]], []) AT_CLEANUP ## ------------------------------------------------------------ ## ## Improper handling of embedded actions and $-N in GLR parsers ## ## ------------------------------------------------------------ ## AT_SETUP([Improper handling of embedded actions and dollar(-N) in GLR parsers]) AT_DATA_GRAMMAR([glr-regr2a.y], [[/* Regression Test: Improper handling of embedded actions and $-N */ /* Reported by S. Eken */ %{ #define YYSTYPE char * #include #include #include #include int yylex (void); void yyerror (char const *); %} %glr-parser %% command: 's' var 't' { printf ("Variable: '%s'\n", $2); } 'v' 'x' 'q' { free ($2); } | 's' var_list 't' 'e' { printf ("Varlist: '%s'\n", $2); free ($2); } | 's' var 't' var_printer 'x' { free ($2); } ; var: 'V' { $$ = $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 #include 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 { $$ = RULE(2); } %merge ; NT2 : NT1 { $$ = RULE(3); } %merge | P1 NT1 O1 T3 P2 { $$ = RULE(4); } %merge ; NT3 : T3 { $$ = RULE(5); } %merge | P1 NT1 O1 T3 P2 { $$ = RULE(6); } %merge ; NT4 : NT3 { $$ = RULE(7); } %merge | NT2 { $$ = RULE(8); } %merge | P1 NT2 O1 NT3 P2 { $$ = RULE(9); } %merge ; NT5 : NT4 { $$ = RULE(10); } %merge ; NT6 : P1 NT1 O1 T3 P2 { $$ = RULE(11) | $2; } %merge | NT5 { $$ = RULE(12) | $1; } %merge ; %% static int MergeRule (int x0, int x1) { return x0 | x1; } static void yyerror(char const * s) { fprintf(stderr,"error: %s\n",s); } FILE *input = NULL; int P[] = { P1, P2 }; int O[] = { O1, O2 }; int T[] = { T1, T2, T3, T4 }; int yylex (void) { char inp[3]; if (fscanf (input, "%2s", inp) == EOF) return 0; switch (inp[0]) { case 'p': return P[inp[1] - '1']; case 't': return T[inp[1] - '1']; case 'o': return O[inp[1] - '1']; } return BAD_CHAR; } int main(int argc, char* argv[]) { input = stdin; if (argc == 2 && !(input = fopen (argv[1], "r"))) return 3; return yyparse (); } ]]) AT_CHECK([[bison -o glr-regr3.c glr-regr3.y]], 0, [], [glr-regr3.y: conflicts: 1 shift/reduce, 1 reduce/reduce ]) AT_COMPILE([glr-regr3]) AT_CHECK([[echo p1 t4 o2 p1 p1 t1 o1 t2 p2 o1 t3 p2 p2 | ./glr-regr3]], 0, [[Result: 1c04 ]], []) AT_CLEANUP ## ------------------------------------------------------------------------- ## ## Duplicate representation of merged trees. See ## ## . ## ## ------------------------------------------------------------------------- ## AT_SETUP([Duplicate representation of merged trees]) AT_DATA_GRAMMAR([glr-regr4.y], [[ %union { char *ptr; } %type S A A1 A2 B %glr-parser %{ #include #include #include static char *merge (YYSTYPE, YYSTYPE); static char *make_value (char const *, char const *); static void yyerror (char const *); static int yylex (void); %} %% tree: S { printf ("%s\n", $1); } ; S: A %merge { $$ = make_value ("S", $1); } | B %merge { $$ = make_value ("S", $1); } ; A: A1 %merge { $$ = make_value ("A", $1); } | A2 %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 ## ## . ## ## -------------------------------------------------------------------------- ## AT_SETUP([User destructor for unresolved GLR semantic value]) AT_DATA_GRAMMAR([glr-regr5.y], [[ %{ #include #include static void yyerror (char const *); static int yylex (void); enum { MAGIC_VALUE = -1057808125 }; /* originally chosen at random */ %} %glr-parser %union { int value; } %type start %destructor { if ($$ != MAGIC_VALUE) { fprintf (stderr, "Bad destructor call.\n"); exit (EXIT_FAILURE); } } start %% start: 'a' { $$ = MAGIC_VALUE; } | 'a' { $$ = MAGIC_VALUE; } ; %% static int yylex (void) { static char const *input = "a"; return *input++; } static void yyerror (char const *msg) { fprintf (stderr, "%s\n", msg); } int main (void) { return yyparse () != 1; } ]]) AT_CHECK([[bison -o glr-regr5.c glr-regr5.y]], 0, [], [glr-regr5.y: conflicts: 1 reduce/reduce ]) AT_COMPILE([glr-regr5]) AT_CHECK([[./glr-regr5]], 0, [], [syntax is ambiguous ]) AT_CLEANUP ## -------------------------------------------------------------------------- ## ## User destructor after an error during a split parse. See ## ## . ## ## -------------------------------------------------------------------------- ## AT_SETUP([User destructor after an error during a split parse]) AT_DATA_GRAMMAR([glr-regr6.y], [[ %{ #include #include static void yyerror (char const *); static int yylex (void); %} %glr-parser %union { int value; } %type 'a' %destructor { printf ("Destructor called.\n"); } 'a' %% start: 'a' | 'a' ; %% static int yylex (void) { static char const *input = "a"; return *input++; } static void yyerror (char const *msg) { fprintf (stderr, "%s\n", msg); } int main (void) { return yyparse () != 1; } ]]) AT_CHECK([[bison -o glr-regr6.c glr-regr6.y]], 0, [], [glr-regr6.y: conflicts: 1 reduce/reduce ]) AT_COMPILE([glr-regr6]) AT_CHECK([[./glr-regr6]], 0, [Destructor called. ], [syntax is ambiguous ]) AT_CLEANUP ## ------------------------------------------------------------------------- ## ## Duplicated user destructor for lookahead. See ## ## . ## ## ------------------------------------------------------------------------- ## AT_SETUP([Duplicated user destructor for lookahead]) AT_DATA_GRAMMAR([glr-regr7.y], [[ %{ #include #include static void yyerror (char const *); static int yylex (void); #define YYSTACKEXPANDABLE 0 %} %glr-parser %union { int *count; } %type 'a' %destructor { if ((*$$)++) 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 #include static void yyerror (char const *); static int yylex (void); static void yyerror (char const *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 (char const *msg) { fprintf (stderr, "%s\n", msg); } 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 ## ## . ## ## ------------------------------------------------------------------------- ## AT_SETUP([No users destructors if stack 0 deleted]) AT_DATA_GRAMMAR([glr-regr9.y], [[ %{ # include # include 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 '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 static void yyerror (char const *); static int yylex (void); #define GARBAGE_SIZE 50 static char garbage[GARBAGE_SIZE]; %} %glr-parser %union { char *ptr; } %type 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 i; for (i = 0; i < GARBAGE_SIZE; i+=1) garbage[i] = 108; return yyparse (); } ]]) AT_CHECK([[bison -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 static void yyerror (char const *); static int yylex (void); static int destructors = 0; # define USE(val) %} %glr-parser %union { int dummy; } %type '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 -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 semantic values if user action cuts parse. ## ## ------------------------------------------------------------------------- ## AT_SETUP([Leaked semantic values if user action cuts parse]) AT_DATA_GRAMMAR([glr-regr12.y], [[ %glr-parser %union { int dummy; } %token PARENT_RHS_AFTER %type parent_rhs_before merged PARENT_RHS_AFTER %destructor { parent_rhs_before_value = 0; } parent_rhs_before %destructor { merged_value = 0; } merged %destructor { parent_rhs_after_value = 0; } PARENT_RHS_AFTER %{ # include static int merge (YYSTYPE, YYSTYPE); static void yyerror (char const *); static int yylex (void); static int parent_rhs_before_value = 0; static int merged_value = 0; static int parent_rhs_after_value = 0; # define USE(val) %} %% start: alt1 %dprec 1 | alt2 %dprec 2 ; alt1: PARENT_RHS_AFTER { USE ($1); parent_rhs_after_value = 0; } ; alt2: parent_rhs_before merged PARENT_RHS_AFTER { USE (($1, $2, $3)); parent_rhs_before_value = 0; merged_value = 0; parent_rhs_after_value = 0; } ; parent_rhs_before: { USE ($$); parent_rhs_before_value = 1; } ; merged: %merge { USE ($$); merged_value = 1; } | cut %merge { USE ($$); merged_value = 1; } ; cut: { 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) { static int const input[] = { PARENT_RHS_AFTER, 0 }; static const int *inputp = input; if (*inputp == PARENT_RHS_AFTER) parent_rhs_after_value = 1; return *inputp++; } int main (void) { int exit_status = yyparse (); if (parent_rhs_before_value) { fprintf (stderr, "`parent_rhs_before' destructor not called.\n"); exit_status = 1; } if (merged_value) { fprintf (stderr, "`merged' destructor not called.\n"); exit_status = 1; } if (parent_rhs_after_value) { fprintf (stderr, "`PARENT_RHS_AFTER' destructor not called.\n"); exit_status = 1; } return exit_status; } ]]) AT_CHECK([[bison -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_CLEANUP ## ------------------------------------------------------------------------- ## ## Incorrect lookahead during deterministic GLR. See ## ## and ## ## . ## ## ------------------------------------------------------------------------- ## 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. - User action changing the lookahead. */ %{ #include static void yyerror (char const *); static int yylex (void); static void print_look_ahead (char const *); #define USE(value) %} %union { char value; } %type 'a' 'b' %glr-parser %locations %% start: defstate_init defstate_shift 'b' change_lookahead 'a' { 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'"); } ; change_lookahead: { yychar = 'a'; } ; %% static void yyerror (char const *msg) { fprintf (stderr, "%s\n", msg); } static int yylex (void) { static char const *input = "ab"; static int i = 0; yylloc.first_line = yylloc.last_line = 1; yylloc.first_column = yylloc.last_column = i + 1; yylval.value = input[i] + 'A' - 'a'; return input[i++]; } 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 -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 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 '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 { $$ = $2; } | alt2 stack_explosion %merge { $$ = $2; } | alt3 stack_explosion %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 i = 0; yylloc.first_line = yylloc.last_line = 1; yylloc.first_column = yylloc.last_column = i + 1; yylval.value = input[i] + 'A' - 'a'; return input[i++]; } 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 -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 ## ------------------------------------------------------------------------- ## ## Leaked semantic values when reporting ambiguity. ## ## ------------------------------------------------------------------------- ## AT_SETUP([Leaked semantic values when reporting ambiguity]) AT_DATA_GRAMMAR([glr-regr15.y], [[ %glr-parser %destructor { parent_rhs_before_value = 0; } parent_rhs_before %{ # include static void yyerror (char const *); static int yylex (void); static int parent_rhs_before_value = 0; # define USE(val) %} %% start: alt1 %dprec 1 | alt2 %dprec 2 ; /* This stack must be merged into the other stacks *last* (added at the beginning of the semantic options list) so that yyparse will choose to clean it up rather than the tree for which some semantic actions have been performed. Thus, if yyreportAmbiguity longjmp's to yyparse, the values from those other trees are not cleaned up. */ alt1: ; alt2: parent_rhs_before ambiguity { USE ($1); parent_rhs_before_value = 0; } ; parent_rhs_before: { USE ($$); parent_rhs_before_value = 1; } ; ambiguity: ambiguity1 | ambiguity2 ; ambiguity1: ; ambiguity2: ; %% static void yyerror (char const *msg) { fprintf (stderr, "%s\n", msg); } static int yylex (void) { return 0; } int main (void) { int exit_status = yyparse () != 1; if (parent_rhs_before_value) { fprintf (stderr, "`parent_rhs_before' destructor not called.\n"); exit_status = 1; } return exit_status; } ]]) AT_CHECK([[bison -o glr-regr15.c glr-regr15.y]], 0, [], [glr-regr15.y: conflicts: 2 reduce/reduce ]) AT_COMPILE([glr-regr15]) AT_CHECK([[./glr-regr15]], 0, [], [syntax is ambiguous ]) AT_CLEANUP ## ------------------------------------------------------------------------- ## ## Leaked lookahead after nondeterministic parse syntax error. ## ## ------------------------------------------------------------------------- ## AT_SETUP([Leaked lookahead after nondeterministic parse syntax error]) AT_DATA_GRAMMAR([glr-regr16.y], [[ %glr-parser %destructor { lookahead_value = 0; } 'b' %{ # include static void yyerror (char const *); static int yylex (void); static int lookahead_value = 0; # define USE(val) %} %% start: alt1 'a' | alt2 'a' ; alt1: ; alt2: ; %% static void yyerror (char const *msg) { fprintf (stderr, "%s\n", msg); } static int yylex (void) { static char const *input = "ab"; if (*input == 'b') lookahead_value = 1; return *input++; } int main (void) { int exit_status = yyparse () != 1; if (lookahead_value) { fprintf (stderr, "Lookahead destructor not called.\n"); exit_status = 1; } return exit_status; } ]]) AT_CHECK([[bison -o glr-regr16.c glr-regr16.y]], 0, [], [glr-regr16.y: conflicts: 1 reduce/reduce ]) AT_COMPILE([glr-regr16]) AT_CHECK([[./glr-regr16]], 0, [], [syntax error ]) AT_CLEANUP ## ------------------------------------------------------------------------- ## ## Uninitialized location when reporting ambiguity. ## ## ------------------------------------------------------------------------- ## AT_SETUP([Uninitialized location when reporting ambiguity]) AT_DATA_GRAMMAR([glr-regr17.y], [[ %glr-parser %locations %pure-parser %error-verbose %union { int dummy; } %{ static void yyerror (YYLTYPE *, char const *); static int yylex (YYSTYPE *, YYLTYPE *); %} %initial-action { @$.first_line = 1; @$.first_column = 1; @$.last_line = 1; @$.last_column = 1; } %% /* 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: ; %% 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); } static int yylex (YYSTYPE *lvalp, YYLTYPE *llocp) { static char const input[] = "ab"; static char const *inputp = input; lvalp->dummy = 0; llocp->first_line = llocp->last_line = 2; llocp->first_column = inputp - input + 1; llocp->last_column = llocp->first_column + 1; return *inputp++; } int main (void) { return yyparse () != 1; } ]]) AT_CHECK([[bison -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_CLEANUP