Reported by Florian Krohm at
<http://lists.gnu.org/archive/html/bug-bison/2009-12/msg00005.html>.
* NEWS (2.4.2): Document.
* src/reader.c (grammar_rule_check): Implement.
(grammar_current_rule_prec_set): Add comments explaining that we
here assume a %prec identifier is a token, but we still manage
to support POSIX.
* tests/input.at (%prec's token must be defined): New test
group.
(cherry picked from commit
f1ceed07743630aa2aef7c77d8bde23c3794ee1b)
+2009-12-30 Joel E. Denny <jdenny@clemson.edu>
+
+ POSIX: warn if %prec's token was not defined.
+ Reported by Florian Krohm at
+ <http://lists.gnu.org/archive/html/bug-bison/2009-12/msg00005.html>.
+ * NEWS (2.4.2): Document.
+ * src/reader.c (grammar_rule_check): Implement.
+ (grammar_current_rule_prec_set): Add comments explaining that we
+ here assume a %prec identifier is a token, but we still manage
+ to support POSIX.
+ * tests/input.at (%prec's token must be defined): New test
+ group.
+
2009-12-31 Joel E. Denny <jdenny@clemson.edu>
* HACKING (Release Procedure): Recommend a secure automake.
2009-12-31 Joel E. Denny <jdenny@clemson.edu>
* HACKING (Release Procedure): Recommend a secure automake.
* Changes in version 2.4.2 (????-??-??):
* Changes in version 2.4.2 (????-??-??):
+** `%prec IDENTIFIER' requires IDENTIFIER to be defined separately.
+
+ POSIX specifies that an error be reported for any identifier that does
+ not appear on the LHS of a grammar rule and that is not defined by
+ %token, %left, %right, or %nonassoc. Bison 2.3b and later lost this
+ error report for the case when an identifier appears only after a
+ %prec directive. It is now restored. However, for backward
+ compatibility with recent Bison releases, it is only a warning for
+ now. In Bison 2.5 and later, it will return to being an error.
+
** Detection of GNU M4 1.4.6 or newer during configure is improved.
** Warnings from gcc's -Wundef option about undefined YYENABLE_NLS,
** Detection of GNU M4 1.4.6 or newer during configure is improved.
** Warnings from gcc's -Wundef option about undefined YYENABLE_NLS,
warn_at (r->location, _("unset value: $$"));
}
}
warn_at (r->location, _("unset value: $$"));
}
}
+
+ /* See comments in grammar_current_rule_prec_set for how POSIX
+ mandates this complaint. It's only for identifiers, so skip
+ it for char literals and strings, which are always tokens. */
+ if (r->ruleprec
+ && r->ruleprec->tag[0] != '\'' && r->ruleprec->tag[0] != '"'
+ && !r->ruleprec->declared && !r->ruleprec->prec)
+ warn_at (r->location, _("token for %%prec is not defined: %s"),
+ r->ruleprec->tag);
void
grammar_current_rule_prec_set (symbol *precsym, location loc)
{
void
grammar_current_rule_prec_set (symbol *precsym, location loc)
{
+ /* POSIX says that any identifier is a nonterminal if it does not
+ appear on the LHS of a grammar rule and is not defined by %token
+ or by one of the directives that assigns precedence to a token. We
+ ignore this here because the only kind of identifier that POSIX
+ allows to follow a %prec is a token and because assuming it's a
+ token now can produce more logical error messages. Nevertheless,
+ grammar_rule_check does obey what we believe is the real intent of
+ POSIX here: that an error be reported for any identifier that
+ appears after %prec but that is not defined separately as a
+ token. */
symbol_class_set (precsym, token_sym, loc, false);
if (current_rule->ruleprec)
complain_at (loc, _("only one %s allowed per rule"), "%prec");
symbol_class_set (precsym, token_sym, loc, false);
if (current_rule->ruleprec)
complain_at (loc, _("only one %s allowed per rule"), "%prec");
+## ------------------------------- ##
+## %prec's token must be defined. ##
+## ------------------------------- ##
+
+AT_SETUP([[%prec's token must be defined]])
+
+# According to POSIX, a %prec token must be defined separately.
+
+AT_DATA([[input.y]],
+[[%%
+start: %prec PREC ;
+]])
+
+AT_BISON_CHECK([[input.y]], [[0]], [],
+[[input.y:2.8-17: warning: token for %prec is not defined: PREC
+]])
+
+AT_CLEANUP
+
+
## -------------------------------- ##
## Reject unused %code qualifiers. ##
## -------------------------------- ##
## -------------------------------- ##
## Reject unused %code qualifiers. ##
## -------------------------------- ##