POSIX: complain if %prec's token was not defined.

[bison.git] / src / reader.c

diff --git a/src/reader.c b/src/reader.c
index 14624df880b56ecd9d0d80425520e801e6cf5406..3f00754131c1fe6e5e92f64ab919781aa094c61d 100644 (file)
--- a/src/reader.c
+++ b/src/reader.c
@@ -320,6 +320,15 @@ grammar_rule_check (const symbol_list *r)
            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)
+    complain_at (r->location, _("token for %%prec is not defined: %s"),
+                 r->ruleprec->tag);
 }
 
 
@@ -396,6 +405,16 @@ grammar_midrule_action (void)
 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");
@@ -608,9 +627,9 @@ prepare_percent_define_front_end_variables (void)
     char *lr_type;
     /* IELR would be a better default, but LALR is historically the
        default.  */
-    muscle_percent_define_default ("lr.type", "LALR");
+    muscle_percent_define_default ("lr.type", "lalr");
     lr_type = muscle_percent_define_get ("lr.type");
-    if (0 != strcmp (lr_type, "canonical LR"))
+    if (0 != strcmp (lr_type, "canonical-lr"))
       muscle_percent_define_default ("lr.default-reductions", "all");
     else
       muscle_percent_define_default ("lr.default-reductions", "accepting");
@@ -620,7 +639,7 @@ prepare_percent_define_front_end_variables (void)
   /* Check %define front-end variables.  */
   {
     static char const * const values[] = {
-      "lr.type", "LALR", "IELR", "canonical LR", NULL,
+      "lr.type", "lalr", "ielr", "canonical-lr", NULL,
       "lr.default-reductions", "all", "consistent", "accepting", NULL,
       NULL
     };
@@ -641,9 +660,6 @@ check_and_convert_grammar (void)
   if (nrules == 0)
     fatal (_("no rules in the input grammar"));
 
-  /* Report any undefined symbols and consider them nonterminals.  */
-  symbols_check_defined ();
-
   /* If the user did not define her ENDTOKEN, do it now. */
   if (!endtoken)
     {
@@ -654,6 +670,9 @@ check_and_convert_grammar (void)
       endtoken->user_token_number = 0;
     }
 
+  /* Report any undefined symbols and consider them nonterminals.  */
+  symbols_check_defined ();
+
   /* Find the start symbol if no %start.  */
   if (!start_flag)
     {