# Executing Actions. -*- Autotest -*- # Copyright (C) 2001, 2002, 2003, 2004, 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([[User Actions.]]) ## ------------------ ## ## Mid-rule actions. ## ## ------------------ ## AT_SETUP([Mid-rule actions]) # Bison once forgot the mid-rule actions. It was because the action # was attached to the host rule (the one with the mid-rule action), # instead of being attached to the empty rule dedicated to this # action. AT_DATA_GRAMMAR([[input.y]], [[%error-verbose %debug %{ # include # include static void yyerror (const char *msg); static int yylex (void); %} %% exp: { putchar ('0'); } '1' { putchar ('1'); } '2' { putchar ('2'); } '3' { putchar ('3'); } '4' { putchar ('4'); } '5' { putchar ('5'); } '6' { putchar ('6'); } '7' { putchar ('7'); } '8' { putchar ('8'); } '9' { putchar ('9'); } { putchar ('\n'); } ; %% static int yylex (void) { static char const input[] = "123456789"; static size_t toknum; if (! (toknum < sizeof input)) abort (); return input[toknum++]; } static void yyerror (const char *msg) { fprintf (stderr, "%s\n", msg); } int main (void) { return yyparse (); } ]]) AT_CHECK([bison -d -v -o input.c input.y]) AT_COMPILE([input]) AT_PARSER_CHECK([./input], 0, [[0123456789 ]]) AT_CLEANUP ## ---------------- ## ## Exotic Dollars. ## ## ---------------- ## AT_SETUP([Exotic Dollars]) AT_DATA_GRAMMAR([[input.y]], [[%error-verbose %debug %{ # include # include static void yyerror (const char *msg); static int yylex (void); # define USE(Var) %} %union { int val; }; %type a_1 a_2 a_5 sum_of_the_five_previous_values %% exp: a_1 a_2 { $$ = 3; } { $$ = $3 + 1; } a_5 sum_of_the_five_previous_values { USE (($1, $2, $3, $4, $5)); printf ("%d\n", $6); } ; a_1: { $$ = 1; }; a_2: { $$ = 2; }; a_5: { $$ = 5; }; sum_of_the_five_previous_values: { $$ = $0 + $-1 + $-2 + $-3 + $-4; } ; %% static int yylex (void) { static int called; if (called++) abort (); return EOF; } static void yyerror (const char *msg) { fprintf (stderr, "%s\n", msg); } int main (void) { return yyparse (); } ]]) AT_CHECK([bison -d -v -o input.c input.y], 0) AT_COMPILE([input]) AT_PARSER_CHECK([./input], 0, [[15 ]]) AT_CLEANUP ## -------------------------- ## ## Printers and Destructors. ## ## -------------------------- ## # _AT_CHECK_PRINTER_AND_DESTRUCTOR($1, $2, $3, $4, BISON-DIRECTIVE, UNION-FLAG) # ----------------------------------------------------------------------------- m4_define([_AT_CHECK_PRINTER_AND_DESTRUCTOR], [# Make sure complex $n work. m4_if([$1$2$3], $[1]$[2]$[3], [], [m4_fatal([$0: Invalid arguments: $@])])dnl # Be sure to pass all the %directives to this macro to have correct # helping macros. So don't put any directly in the Bison file. AT_BISON_OPTION_PUSHDEFS([$5]) AT_DATA_GRAMMAR([[input.y]], [[%requires { #include #include #include #include #define YYINITDEPTH 10 #define YYMAXDEPTH 10 ]AT_LALR1_CC_IF( [#define RANGE(Location) (Location).begin.line, (Location).end.line], [#define RANGE(Location) (Location).first_line, (Location).last_line]) [} $5] m4_ifval([$6], [%union { int ival; }]) AT_LALR1_CC_IF([%define "global_tokens_and_yystype"]) m4_ifval([$6], [[%provides {]], [[%code {]]) AT_LALR1_CC_IF([typedef yy::location YYLTYPE;]) [static int yylex (]AT_LEX_FORMALS[); ]AT_LALR1_CC_IF([], [static void yyerror (const char *msg);]) [} ]m4_ifval([$6], [%type '(' 'x' 'y' ')' ';' thing line input END])[ /* FIXME: This %printer isn't actually tested. */ %printer { ]AT_LALR1_CC_IF([debug_stream () << $$;], [fprintf (yyoutput, "%d", $$)])[; } input line thing 'x' 'y' %destructor { printf ("Freeing nterm input (%d@%d-%d)\n", $$, RANGE (@$)); } input %destructor { printf ("Freeing nterm line (%d@%d-%d)\n", $$, RANGE (@$)); } line %destructor { printf ("Freeing nterm thing (%d@%d-%d)\n", $$, RANGE (@$)); } thing %destructor { printf ("Freeing token 'x' (%d@%d-%d)\n", $$, RANGE (@$)); } 'x' %destructor { printf ("Freeing token 'y' (%d@%d-%d)\n", $$, RANGE (@$)); } 'y' %token END 0 %destructor { printf ("Freeing token END (%d@%d-%d)\n", $$, RANGE (@$)); } END %% /* This grammar is made to exercise error recovery. "Lines" starting with `(' support error recovery, with ')' as synchronizing token. Lines starting with 'x' can never be recovered from if in error. */ input: /* Nothing. */ { $$ = 0; printf ("input (%d@%d-%d): /* Nothing */\n", $$, RANGE (@$)); } | line input /* Right recursive to load the stack so that popping at END can be exercised. */ { $$ = 2; printf ("input (%d@%d-%d): line (%d@%d-%d) input (%d@%d-%d)\n", $$, RANGE (@$), $1, RANGE (@1), $2, RANGE (@2)); } ; line: thing thing thing ';' { $$ = $1; printf ("line (%d@%d-%d): thing (%d@%d-%d) thing (%d@%d-%d) thing (%d@%d-%d) ';' (%d@%d-%d)\n", $$, RANGE (@$), $1, RANGE (@1), $2, RANGE (@2), $3, RANGE (@3), $4, RANGE (@4)); } | '(' thing thing ')' { $$ = $1; printf ("line (%d@%d-%d): '(' (%d@%d-%d) thing (%d@%d-%d) thing (%d@%d-%d) ')' (%d@%d-%d)\n", $$, RANGE (@$), $1, RANGE (@1), $2, RANGE (@2), $3, RANGE (@3), $4, RANGE (@4)); } | '(' thing ')' { $$ = $1; printf ("line (%d@%d-%d): '(' (%d@%d-%d) thing (%d@%d-%d) ')' (%d@%d-%d)\n", $$, RANGE (@$), $1, RANGE (@1), $2, RANGE (@2), $3, RANGE (@3)); } | '(' error ')' { $$ = -1; printf ("line (%d@%d-%d): '(' (%d@%d-%d) error (@%d-%d) ')' (%d@%d-%d)\n", $$, RANGE (@$), $1, RANGE (@1), RANGE (@2), $3, RANGE (@3)); } ; thing: 'x' { $$ = $1; printf ("thing (%d@%d-%d): 'x' (%d@%d-%d)\n", $$, RANGE (@$), $1, RANGE (@1)); } ; %% /* Alias to ARGV[1]. */ const char *source = 0; static int yylex (]AT_LEX_FORMALS[) { static unsigned int counter = 0; int c = ]AT_VAL[]m4_ifval([$6], [.ival])[ = counter++; /* As in BASIC, line numbers go from 10 to 10. */ ]AT_LALR1_CC_IF( [ AT_LOC.begin.line = AT_LOC.begin.column = 10 * c; AT_LOC.end.line = AT_LOC.end.column = AT_LOC.begin.line + 9; ], [ AT_LOC.first_line = AT_LOC.first_column = 10 * c; AT_LOC.last_line = AT_LOC.last_column = AT_LOC.first_line + 9; ])[ if (! (0 <= c && c <= strlen (source))) abort (); if (source[c]) printf ("sending: '%c'", source[c]); else printf ("sending: END"); printf (" (%d@%d-%d)\n", c, RANGE (]AT_LOC[)); return source[c]; } ]AT_LALR1_CC_IF( [/* A C++ error reporting function. */ void yy::parser::error (const location& l, const std::string& m) { printf ("%d-%d: %s\n", RANGE (l), m.c_str()); } static bool yydebug; int yyparse () { yy::parser parser; parser.set_debug_level (yydebug); return parser.parse (); } ], [static void yyerror (const char *msg) { printf ("%d-%d: %s\n", RANGE (yylloc), msg); }])[ int main (int argc, const char *argv[]) { int status; yydebug = !!getenv ("YYDEBUG"); assert (argc == 2); source = argv[1]; status = yyparse (); switch (status) { case 0: printf ("Successful parse.\n"); break; case 1: printf ("Parsing FAILED.\n"); break; default: printf ("Parsing FAILED (status %d).\n", status); break; } return status; } ]]) AT_LALR1_CC_IF( [AT_CHECK([bison -o input.cc input.y]) AT_COMPILE_CXX([input])], [AT_CHECK([bison -o input.c input.y]) AT_COMPILE([input])]) # Check the location of "empty" # ----------------------------- # I.e., epsilon-reductions, as in "(x)" which ends by reducing # an empty "line" nterm. # FIXME: This location is not satisfying. Depend on the lookahead? AT_PARSER_CHECK([./input '(x)'], 0, [[sending: '(' (0@0-9) sending: 'x' (1@10-19) thing (1@10-19): 'x' (1@10-19) sending: ')' (2@20-29) line (0@0-29): '(' (0@0-9) thing (1@10-19) ')' (2@20-29) sending: END (3@30-39) input (0@29-29): /* Nothing */ input (2@0-29): line (0@0-29) input (0@29-29) Freeing token END (3@30-39) Freeing nterm input (2@0-29) Successful parse. ]]) # Check locations in error recovery # --------------------------------- # '(y)' is an error, but can be recovered from. But what's the location # of the error itself ('y'), and of the resulting reduction ('(error)'). AT_PARSER_CHECK([./input '(y)'], 0, [[sending: '(' (0@0-9) sending: 'y' (1@10-19) 10-19: syntax error, unexpected 'y', expecting 'x' Freeing token 'y' (1@10-19) sending: ')' (2@20-29) line (-1@0-29): '(' (0@0-9) error (@10-19) ')' (2@20-29) sending: END (3@30-39) input (0@29-29): /* Nothing */ input (2@0-29): line (-1@0-29) input (0@29-29) Freeing token END (3@30-39) Freeing nterm input (2@0-29) Successful parse. ]]) # Syntax errors caught by the parser # ---------------------------------- # Exercise the discarding of stack top and input until `error' # can be reduced. # # '(', 'x', 'x', 'x', 'x', 'x', ')', # # Load the stack and provoke an error that cannot be caught by the # grammar, to check that the stack is cleared. And make sure the # lookahead is freed. # # '(', 'x', ')', # '(', 'x', ')', # 'y' AT_PARSER_CHECK([./input '(xxxxx)(x)(x)y'], 1, [[sending: '(' (0@0-9) sending: 'x' (1@10-19) thing (1@10-19): 'x' (1@10-19) sending: 'x' (2@20-29) thing (2@20-29): 'x' (2@20-29) sending: 'x' (3@30-39) 30-39: syntax error, unexpected 'x', expecting ')' Freeing nterm thing (2@20-29) Freeing nterm thing (1@10-19) Freeing token 'x' (3@30-39) sending: 'x' (4@40-49) Freeing token 'x' (4@40-49) sending: 'x' (5@50-59) Freeing token 'x' (5@50-59) sending: ')' (6@60-69) line (-1@0-69): '(' (0@0-9) error (@10-59) ')' (6@60-69) sending: '(' (7@70-79) sending: 'x' (8@80-89) thing (8@80-89): 'x' (8@80-89) sending: ')' (9@90-99) line (7@70-99): '(' (7@70-79) thing (8@80-89) ')' (9@90-99) sending: '(' (10@100-109) sending: 'x' (11@110-119) thing (11@110-119): 'x' (11@110-119) sending: ')' (12@120-129) line (10@100-129): '(' (10@100-109) thing (11@110-119) ')' (12@120-129) sending: 'y' (13@130-139) input (0@129-129): /* Nothing */ input (2@100-129): line (10@100-129) input (0@129-129) input (2@70-129): line (7@70-99) input (2@100-129) input (2@0-129): line (-1@0-69) input (2@70-129) 130-139: syntax error, unexpected 'y', expecting END Freeing nterm input (2@0-129) Freeing token 'y' (13@130-139) Parsing FAILED. ]]) # Syntax error caught by the parser where lookahead = END # -------------------------------------------------------- # Load the stack and provoke an error that cannot be caught by the # grammar, to check that the stack is cleared. And make sure the # lookahead is freed. # # '(', 'x', ')', # '(', 'x', ')', # 'x' AT_PARSER_CHECK([./input '(x)(x)x'], 1, [[sending: '(' (0@0-9) sending: 'x' (1@10-19) thing (1@10-19): 'x' (1@10-19) sending: ')' (2@20-29) line (0@0-29): '(' (0@0-9) thing (1@10-19) ')' (2@20-29) sending: '(' (3@30-39) sending: 'x' (4@40-49) thing (4@40-49): 'x' (4@40-49) sending: ')' (5@50-59) line (3@30-59): '(' (3@30-39) thing (4@40-49) ')' (5@50-59) sending: 'x' (6@60-69) thing (6@60-69): 'x' (6@60-69) sending: END (7@70-79) 70-79: syntax error, unexpected END, expecting 'x' Freeing nterm thing (6@60-69) Freeing nterm line (3@30-59) Freeing nterm line (0@0-29) Freeing token END (7@70-79) Parsing FAILED. ]]) # Check destruction upon stack overflow # ------------------------------------- # Upon stack overflow, all symbols on the stack should be destroyed. # Only check for yacc.c. AT_YACC_IF([ AT_PARSER_CHECK([./input '(x)(x)(x)(x)(x)(x)(x)'], 2, [[sending: '(' (0@0-9) sending: 'x' (1@10-19) thing (1@10-19): 'x' (1@10-19) sending: ')' (2@20-29) line (0@0-29): '(' (0@0-9) thing (1@10-19) ')' (2@20-29) sending: '(' (3@30-39) sending: 'x' (4@40-49) thing (4@40-49): 'x' (4@40-49) sending: ')' (5@50-59) line (3@30-59): '(' (3@30-39) thing (4@40-49) ')' (5@50-59) sending: '(' (6@60-69) sending: 'x' (7@70-79) thing (7@70-79): 'x' (7@70-79) sending: ')' (8@80-89) line (6@60-89): '(' (6@60-69) thing (7@70-79) ')' (8@80-89) sending: '(' (9@90-99) sending: 'x' (10@100-109) thing (10@100-109): 'x' (10@100-109) sending: ')' (11@110-119) line (9@90-119): '(' (9@90-99) thing (10@100-109) ')' (11@110-119) sending: '(' (12@120-129) sending: 'x' (13@130-139) thing (13@130-139): 'x' (13@130-139) sending: ')' (14@140-149) line (12@120-149): '(' (12@120-129) thing (13@130-139) ')' (14@140-149) sending: '(' (15@150-159) sending: 'x' (16@160-169) thing (16@160-169): 'x' (16@160-169) sending: ')' (17@170-179) line (15@150-179): '(' (15@150-159) thing (16@160-169) ')' (17@170-179) sending: '(' (18@180-189) sending: 'x' (19@190-199) thing (19@190-199): 'x' (19@190-199) sending: ')' (20@200-209) 200-209: memory exhausted Freeing nterm thing (19@190-199) Freeing nterm line (15@150-179) Freeing nterm line (12@120-149) Freeing nterm line (9@90-119) Freeing nterm line (6@60-89) Freeing nterm line (3@30-59) Freeing nterm line (0@0-29) Parsing FAILED (status 2). ]]) ]) ]) # AT_CHECK_PRINTER_AND_DESTRUCTOR([BISON-OPTIONS], [UNION-FLAG], [SKIP_FLAG]) # --------------------------------------------------------------------------- m4_define([AT_CHECK_PRINTER_AND_DESTRUCTOR], [AT_SETUP([Printers and Destructors $2: $1]) $3 _AT_CHECK_PRINTER_AND_DESTRUCTOR($[1], $[2], $[3], $[4], [%error-verbose %debug %verbose %locations $1], [$2]) AT_CLEANUP ]) AT_CHECK_PRINTER_AND_DESTRUCTOR([]) AT_CHECK_PRINTER_AND_DESTRUCTOR([], [with union]) AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "lalr1.cc"]) AT_CHECK_PRINTER_AND_DESTRUCTOR([%defines %skeleton "lalr1.cc"], [with union]) AT_CHECK_PRINTER_AND_DESTRUCTOR([%glr-parser]) AT_CHECK_PRINTER_AND_DESTRUCTOR([%glr-parser], [with union]) ## --------------------------------- ## ## Default %printer and %destructor. ## ## --------------------------------- ## # Check that the right %printer and %destructor are called, that they're not # called for $end, and that $$ and @$ work correctly. AT_SETUP([Default %printer and %destructor]) AT_DATA_GRAMMAR([[input.y]], [[%error-verbose %debug %locations %initial-action { @$.first_line = @$.last_line = 1; @$.first_column = @$.last_column = 1; } %{ # include # include static void yyerror (const char *msg); static int yylex (void); # define USE(SYM) %} %printer { fprintf (yyoutput, "Default printer for '%c' @ %d", $$, @$.first_column); } %symbol-default %destructor { fprintf (stdout, "Default destructor for '%c' @ %d.\n", $$, @$.first_column); } %symbol-default %printer { fprintf (yyoutput, "'b'/'c' printer for '%c' @ %d", $$, @$.first_column); } 'b' 'c' %destructor { fprintf (stdout, "'b'/'c' destructor for '%c' @ %d.\n", $$, @$.first_column); } 'b' 'c' %% start: 'a' 'b' 'c' 'd' 'e' { $$ = 'S'; USE(($1, $2, $3, $4, $5)); } ; %% static int yylex (void) { static char const input[] = "abcd"; static size_t toknum; if (! (toknum < sizeof input)) abort (); yylval = input[toknum++]; yylloc.first_line = yylloc.last_line = 1; yylloc.first_column = yylloc.last_column = toknum; return yylval; } static void yyerror (const char *msg) { fprintf (stderr, "%s\n", msg); } int main (void) { yydebug = 1; return yyparse (); } ]]) AT_CHECK([bison -o input.c input.y]) AT_COMPILE([input]) AT_PARSER_CHECK([./input], 1, [[Default destructor for 'd' @ 4. 'b'/'c' destructor for 'c' @ 3. 'b'/'c' destructor for 'b' @ 2. Default destructor for 'a' @ 1. ]], [[Starting parse Entering state 0 Reading a token: Next token is token 'a' (1.1-1.1: Default printer for 'a' @ 1) Shifting token 'a' (1.1-1.1: Default printer for 'a' @ 1) Entering state 1 Reading a token: Next token is token 'b' (1.2-1.2: 'b'/'c' printer for 'b' @ 2) Shifting token 'b' (1.2-1.2: 'b'/'c' printer for 'b' @ 2) Entering state 3 Reading a token: Next token is token 'c' (1.3-1.3: 'b'/'c' printer for 'c' @ 3) Shifting token 'c' (1.3-1.3: 'b'/'c' printer for 'c' @ 3) Entering state 5 Reading a token: Next token is token 'd' (1.4-1.4: Default printer for 'd' @ 4) Shifting token 'd' (1.4-1.4: Default printer for 'd' @ 4) Entering state 6 Reading a token: Now at end of input. syntax error, unexpected $end, expecting 'e' Error: popping token 'd' (1.4-1.4: Default printer for 'd' @ 4) Stack now 0 1 3 5 Error: popping token 'c' (1.3-1.3: 'b'/'c' printer for 'c' @ 3) Stack now 0 1 3 Error: popping token 'b' (1.2-1.2: 'b'/'c' printer for 'b' @ 2) Stack now 0 1 Error: popping token 'a' (1.1-1.1: Default printer for 'a' @ 1) Stack now 0 Cleanup: discarding lookahead token $end (1.5-1.5: ) Stack now 0 ]]) AT_CLEANUP ## ----------------------------------- ## ## Per-type %printer and %destructor. ## ## ----------------------------------- ## AT_SETUP([Per-type %printer and %destructor]) AT_DATA_GRAMMAR([[input.y]], [[%error-verbose %debug %{ # include # include static void yyerror (const char *msg); static int yylex (void); # define USE(SYM) %} %union { int field0; int field1; int field2; } %type start 'a' 'g' %type 'e' %type 'f' %printer { fprintf (yyoutput, "%%symbol-default//e printer"); } %symbol-default 'e' %destructor { fprintf (stdout, "%%symbol-default//e destructor.\n"); } %symbol-default 'e' %type 'b' %printer { fprintf (yyoutput, " printer"); } %destructor { fprintf (stdout, " destructor.\n"); } %type 'c' %printer { fprintf (yyoutput, "'c' printer"); } 'c' %destructor { fprintf (stdout, "'c' destructor.\n"); } 'c' %type 'd' %printer { fprintf (yyoutput, "'d' printer"); } 'd' %destructor { fprintf (stdout, "'d' destructor.\n"); } 'd' %% start: 'a' 'b' 'c' 'd' 'e' 'f' 'g' { USE(($1, $2, $3, $4, $5, $6, $7)); $$ = 'S'; } ; %% static int yylex (void) { static char const input[] = "abcdef"; static size_t toknum; if (! (toknum < sizeof input)) abort (); return input[toknum++]; } static void yyerror (const char *msg) { fprintf (stderr, "%s\n", msg); } int main (void) { yydebug = 1; return yyparse (); } ]]) AT_CHECK([bison -o input.c input.y]) AT_COMPILE([input]) AT_PARSER_CHECK([./input], 1, [[%symbol-default//e destructor. %symbol-default//e destructor. 'd' destructor. 'c' destructor. destructor. %symbol-default//e destructor. ]], [[Starting parse Entering state 0 Reading a token: Next token is token 'a' (%symbol-default//e printer) Shifting token 'a' (%symbol-default//e printer) Entering state 1 Reading a token: Next token is token 'b' ( printer) Shifting token 'b' ( printer) Entering state 3 Reading a token: Next token is token 'c' ('c' printer) Shifting token 'c' ('c' printer) Entering state 5 Reading a token: Next token is token 'd' ('d' printer) Shifting token 'd' ('d' printer) Entering state 6 Reading a token: Next token is token 'e' (%symbol-default//e printer) Shifting token 'e' (%symbol-default//e printer) Entering state 7 Reading a token: Next token is token 'f' (%symbol-default//e printer) Shifting token 'f' (%symbol-default//e printer) Entering state 8 Reading a token: Now at end of input. syntax error, unexpected $end, expecting 'g' Error: popping token 'f' (%symbol-default//e printer) Stack now 0 1 3 5 6 7 Error: popping token 'e' (%symbol-default//e printer) Stack now 0 1 3 5 6 Error: popping token 'd' ('d' printer) Stack now 0 1 3 5 Error: popping token 'c' ('c' printer) Stack now 0 1 3 Error: popping token 'b' ( printer) Stack now 0 1 Error: popping token 'a' (%symbol-default//e printer) Stack now 0 Cleanup: discarding lookahead token $end () Stack now 0 ]]) AT_CLEANUP ## ------------------------------------------------------------- ## ## Default %printer and %destructor for user-defined end token. ## ## ------------------------------------------------------------- ## AT_SETUP([Default %printer and %destructor for user-defined end token]) AT_DATA_GRAMMAR([[input.y]], [[%error-verbose %debug %locations %initial-action { @$.first_line = @$.last_line = 1; @$.first_column = @$.last_column = 1; } %{ # include # include static void yyerror (const char *msg); static int yylex (void); # define USE(SYM) %} %token END 0 %printer { fprintf (yyoutput, "Default printer for '%c' @ %d", $$, @$.first_column); } %symbol-default %destructor { fprintf (stdout, "Default destructor for '%c' @ %d.\n", $$, @$.first_column); } %symbol-default %% start: { $$ = 'S'; } ; %% static int yylex (void) { static int called; if (called++) abort (); yylval = 'E'; yylloc.first_line = yylloc.last_line = 1; yylloc.first_column = yylloc.last_column = 1; return 0; } static void yyerror (const char *msg) { fprintf (stderr, "%s\n", msg); } int main (void) { yydebug = 1; return yyparse (); } ]]) AT_CHECK([bison -o input.c input.y]) AT_COMPILE([input]) AT_PARSER_CHECK([./input], 0, [[Default destructor for 'E' @ 1. Default destructor for 'S' @ 1. ]], [[Starting parse Entering state 0 Reducing stack by rule 1 (line 35): -> $$ = nterm start (1.1-1.1: Default printer for 'S' @ 1) Stack now 0 Entering state 1 Reading a token: Now at end of input. Shifting token END (1.1-1.1: Default printer for 'E' @ 1) Entering state 2 Stack now 0 1 2 Cleanup: popping token END (1.1-1.1: Default printer for 'E' @ 1) Cleanup: popping nterm start (1.1-1.1: Default printer for 'S' @ 1) ]]) AT_CLEANUP ## ------------------------------------------------------------------ ## ## Default %printer and %destructor are not for error or $undefined. ## ## ------------------------------------------------------------------ ## AT_SETUP([Default %printer and %destructor are not for error or \$undefined]) # If Bison were to apply the default %printer and %destructor to the error # token or to $undefined: # - For the error token: # - It would generate warnings for unused $n. # - It would invoke the %printer and %destructor on the error token's # semantic value, which would be initialized from the lookahead, which # would be destroyed separately. # - For $undefined, who knows what the semantic value would be. AT_DATA_GRAMMAR([[input.y]], [[%debug %{ # include # include static void yyerror (const char *msg); static int yylex (void); # define USE(SYM) %} %printer { fprintf (yyoutput, "'%c'", $$); } %symbol-default %destructor { fprintf (stderr, "DESTROY '%c'\n", $$); } %symbol-default %% start: { $$ = 'S'; } /* In order to reveal the problems that this bug caused during parsing, add * $2 to USE. */ | 'a' error 'b' 'c' { USE(($1, $3, $4)); $$ = 'S'; } ; %% static int yylex (void) { static char const input[] = "abd"; static size_t toknum; if (! (toknum < sizeof input)) abort (); yylval = input[toknum++]; return yylval; } static void yyerror (const char *msg) { fprintf (stderr, "%s\n", msg); } int main (void) { yydebug = 1; return yyparse (); } ]]) AT_CHECK([bison -o input.c input.y]) AT_COMPILE([input]) AT_PARSER_CHECK([./input], [1], [], [[Starting parse Entering state 0 Reading a token: Next token is token 'a' ('a') Shifting token 'a' ('a') Entering state 1 Reading a token: Next token is token 'b' ('b') syntax error Shifting token error () Entering state 3 Next token is token 'b' ('b') Shifting token 'b' ('b') Entering state 5 Reading a token: Next token is token $undefined () Error: popping token 'b' ('b') DESTROY 'b' Stack now 0 1 3 Error: popping token error () Stack now 0 1 Shifting token error () Entering state 3 Next token is token $undefined () Error: discarding token $undefined () Error: popping token error () Stack now 0 1 Shifting token error () Entering state 3 Reading a token: Now at end of input. Cleanup: discarding lookahead token $end () Stack now 0 1 3 Cleanup: popping token error () Cleanup: popping token 'a' ('a') DESTROY 'a' ]]) AT_CLEANUP ## ------------------------------------------------------ ## ## Default %printer and %destructor are not for $accept. ## ## ------------------------------------------------------ ## AT_SETUP([Default %printer and %destructor are not for \$accept]) # If YYSTYPE is a union and Bison were to apply the default %printer and # %destructor to $accept: # - The %printer and %destructor code generated for $accept would always be # dead code because $accept is currently never shifted onto the stack. # - $$ for $accept would always be of type YYSTYPE because it's not possible # to declare `%type $accept'. (Also true for $undefined.) # - Thus, the compiler might complain that the user code assumes the wrong # type for $$ since the code might assume the type associated with a # specific union field, which is especially reasonable in C++ since that # type may be a base type. This test case checks for this problem. (Also # true for $undefined and the error token, so there are three warnings for # %printer and three for %destructor.) AT_DATA_GRAMMAR([[input.y]], [[%debug /* So that %printer is actually compiled. */ %{ # include # include static void yyerror (const char *msg); static int yylex (void); # define USE(SYM) %} %printer { char chr = $$; fprintf (yyoutput, "'%c'", chr); } %symbol-default %destructor { char chr = $$; fprintf (stderr, "DESTROY '%c'\n", chr); } %symbol-default %union { char chr; } %type start %% start: { USE($$); } ; %% static int yylex (void) { static int called; if (called++) abort (); return 0; } static void yyerror (const char *msg) { fprintf (stderr, "%s\n", msg); } int main (void) { return yyparse (); } ]]) AT_CHECK([bison -o input.c input.y]) AT_COMPILE([input]) AT_CLEANUP