+
+
+
+## ------------------------------------------------------------- ##
+## Default %printer and %destructor for user-defined end token. ##
+## ------------------------------------------------------------- ##
+
+AT_SETUP([Default %printer and %destructor for user-defined end token])
+
+# _AT_CHECK_DEFAULT_PRINTER_AND_DESTRUCTOR_FOR_END_TOKEN(TYPED)
+# -----------------------------------------------------------------------------
+m4_define([_AT_CHECK_DEFAULT_PRINTER_AND_DESTRUCTOR_FOR_END_TOKEN],
+[m4_if($1, 0,
+ [m4_pushdef([kind], []) m4_pushdef([not_kind], [*])],
+ [m4_pushdef([kind], [*]) m4_pushdef([not_kind], [])])
+
+AT_DATA_GRAMMAR([[input]]$1[[.y]],
+[[%error-verbose
+%debug
+%locations
+%initial-action {
+ @$.first_line = @$.last_line = 1;
+ @$.first_column = @$.last_column = 1;
+}
+
+%{
+# include <stdio.h>
+# include <stdlib.h>
+ static void yyerror (const char *msg);
+ static int yylex (void);
+# define USE(SYM)
+%}
+
+%destructor {
+ fprintf (yyoutput, "<]]not_kind[[> destructor should not be called.\n");
+} <]]not_kind[[>
+
+%token END 0
+%printer {
+ fprintf (yyoutput, "<]]kind[[> for '%c' @ %d", $$, @$.first_column);
+} <]]kind[[>
+%destructor {
+ fprintf (stdout, "<]]kind[[> for '%c' @ %d.\n", $$, @$.first_column);
+} <]]kind[[>
+
+%printer {
+ fprintf (yyoutput, "<]]not_kind[[> printer should not be called.\n");
+} <]]not_kind[[>
+
+]]m4_if($1, 0, [[[
+]]],
+[[[%union { char tag; }
+%type <tag> start END]]])[[
+
+%%
+
+start: { $$ = 'S'; } ;
+
+%%
+
+static int
+yylex (void)
+{
+ static int called;
+ if (called++)
+ abort ();
+ yylval]]m4_if($1, 0,, [[[.tag]]])[[ = 'E';
+ yylloc.first_line = yylloc.last_line = 1;
+ yylloc.first_column = yylloc.last_column = 1;
+ return 0;
+}
+
+static void
+yyerror (const char *msg)
+{
+ fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+ yydebug = 1;
+ return yyparse ();
+}
+]])
+
+AT_CHECK([bison -o input$1.c input$1.y])
+AT_COMPILE([input$1])
+AT_PARSER_CHECK([./input$1], 0,
+[[<]]kind[[> for 'E' @ 1.
+<]]kind[[> for 'S' @ 1.
+]],
+[[Starting parse
+Entering state 0
+Reducing stack by rule 1 (line 46):
+-> $$ = nterm start (1.1-1.1: <]]kind[[> for 'S' @ 1)
+Stack now 0
+Entering state 1
+Reading a token: Now at end of input.
+Shifting token END (1.1-1.1: <]]kind[[> for 'E' @ 1)
+Entering state 2
+Stack now 0 1 2
+Cleanup: popping token END (1.1-1.1: <]]kind[[> for 'E' @ 1)
+Cleanup: popping nterm start (1.1-1.1: <]]kind[[> for 'S' @ 1)
+]])
+
+m4_popdef([kind])
+m4_popdef([not_kind])
+])
+
+_AT_CHECK_DEFAULT_PRINTER_AND_DESTRUCTOR_FOR_END_TOKEN(0)
+_AT_CHECK_DEFAULT_PRINTER_AND_DESTRUCTOR_FOR_END_TOKEN(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 <stdio.h>
+# include <stdlib.h>
+ static void yyerror (const char *msg);
+ static int yylex (void);
+# define USE(SYM)
+%}
+
+%printer {
+ fprintf (yyoutput, "'%c'", $$);
+} <> <*>
+%destructor {
+ fprintf (stderr, "DESTROY '%c'\n", $$);
+} <> <*>
+
+%%
+
+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.
+# - $$ for $accept would always be of type YYSTYPE because it's not possible
+# to declare `%type <field> $accept'. (Also true for $undefined.)
+# - Thus, the compiler might complain that the user code assumes the wrong
+# type for $$ 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 <stdio.h>
+# include <stdlib.h>
+ static void yyerror (const char *msg);
+ static int yylex (void);
+# define USE(SYM)
+%}
+
+%printer {
+ char chr = $$;
+ fprintf (yyoutput, "'%c'", chr);
+} <> <*>
+%destructor {
+ char chr = $$;
+ fprintf (stderr, "DESTROY '%c'\n", chr);
+} <> <*>
+
+%union { char chr; }
+%type <chr> start
+
+%%
+
+start: { USE($$); } ;
+
+%%
+
+static int
+yylex (void)
+{
+ static int called;
+ if (called++)
+ abort ();
+ return 0;
+}
+
+static void
+yyerror (const char *msg)
+{
+ fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+ return yyparse ();
+}
+]])
+
+AT_CHECK([bison -o input.c input.y])
+AT_COMPILE([input])
+
+AT_CLEANUP
+
+
+
+## ------------------------------------------------------ ##
+## Default %printer and %destructor for mid-rule values. ##
+## ------------------------------------------------------ ##
+
+AT_SETUP([Default %printer and %destructor for mid-rule values])
+
+AT_DATA_GRAMMAR([[input.y]],
+[[%debug /* So that %printer is actually compiled. */
+
+%{
+# include <stdio.h>
+# include <stdlib.h>
+ static void yyerror (const char *msg);
+ static int yylex (void);
+# define USE(SYM)
+# define YYLTYPE int
+# define YYLLOC_DEFAULT(Current, Rhs, N)
+# define YY_LOCATION_PRINT(File, Loc)
+%}
+
+%printer { fprintf (yyoutput, "%d", @$); } <>
+%destructor { fprintf (stderr, "DESTROY %d\n", @$); } <>
+%printer { fprintf (yyoutput, "<*> printer should not be called"); } <*>
+%destructor { fprintf (yyoutput, "<*> destructor should not be called"); } <*>
+
+%%
+
+start:
+ { @$ = 1; } // Not set or used.
+ { USE ($$); @$ = 2; } // Both set and used.
+ { USE ($$); @$ = 3; } // Only set.
+ { @$ = 4; } // Only used.
+ 'c'
+ { USE (($$, $2, $4, $5)); @$ = 0; }
+ ;
+
+%%
+
+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)
+{
+ yydebug = 1;
+ return yyparse ();
+}
+]])
+
+AT_CHECK([bison -o input.c input.y], 0,,
+[[input.y:33.3-23: warning: unset value: $$
+input.y:30.3-35.37: warning: unused value: $3
+]])
+
+AT_COMPILE([input])
+AT_PARSER_CHECK([./input], 1,,
+[[Starting parse
+Entering state 0
+Reducing stack by rule 1 (line 30):
+-> $$ = nterm $@1 (: )
+Stack now 0
+Entering state 2
+Reducing stack by rule 2 (line 31):
+-> $$ = nterm @2 (: 2)
+Stack now 0 2
+Entering state 4
+Reducing stack by rule 3 (line 32):
+-> $$ = nterm @3 (: 3)
+Stack now 0 2 4
+Entering state 5
+Reducing stack by rule 4 (line 33):
+-> $$ = nterm @4 (: 4)
+Stack now 0 2 4 5
+Entering state 6
+Reading a token: Now at end of input.
+syntax error
+Error: popping nterm @4 (: 4)
+DESTROY 4
+Stack now 0 2 4 5
+Error: popping nterm @3 (: 3)
+DESTROY 3
+Stack now 0 2 4
+Error: popping nterm @2 (: 2)
+DESTROY 2
+Stack now 0 2
+Error: popping nterm $@1 (: )
+Stack now 0
+Cleanup: discarding lookahead token $end (: )
+Stack now 0
+]])
+
+AT_CLEANUP
+
+
+## ----------------------- ##
+## @$ implies %locations. ##
+## ----------------------- ##
+
+# Bison once forgot to check for @$ in actions other than semantic actions.
+
+# AT_CHECK_ACTION_LOCATIONS(ACTION-DIRECTIVE)
+# -------------------------------------------------------
+m4_define([AT_CHECK_ACTION_LOCATIONS],
+[AT_SETUP([[@$ in ]$1[ implies %locations]])
+
+AT_DATA_GRAMMAR([[input.y]],
+[[%code {
+ #include <stdio.h>
+ static int yylex (void);
+ static void yyerror (char const *msg);
+}
+
+%debug
+
+]$1[ {
+ printf ("%d\n", @$.first_line);
+} ]m4_if($1, [%initial-action], [], [[start]])[
+
+%%
+
+start: ;
+
+%%
+
+static int
+yylex (void)
+{
+ return 0;
+}
+
+static void
+yyerror (char const *msg)
+{
+ fprintf (stderr, "%s\n", msg);
+}
+
+int
+main (void)
+{
+ return yyparse ();
+}
+]])
+
+AT_CHECK([[bison -o input.c input.y]])
+AT_COMPILE([[input]])
+
+AT_CLEANUP])
+
+AT_CHECK_ACTION_LOCATIONS([[%initial-action]])
+AT_CHECK_ACTION_LOCATIONS([[%destructor]])
+AT_CHECK_ACTION_LOCATIONS([[%printer]])
projects / bison.git / blobdiff