X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/040984073a54b4c603172be3c3f44b908ea5deb9..4d56beff96de67083b357bffa76f110166a9b67c:/src/reader.c

diff --git a/src/reader.c b/src/reader.c
index 6b247b7f..0e0a8c21 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -20,6 +20,7 @@
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA 02110-1301, USA.  */
 
+#include <config.h>
 #include "system.h"
 
 #include <quotearg.h>
@@ -39,7 +40,7 @@ static symbol_list *grammar = NULL;
 static bool start_flag = false;
 merger_list *merge_functions;
 
-/* Has %union been seen?  */
+/* Was %union seen?  */
 bool typed = false;
 
 /* Should rules have a default precedence?  */
@@ -103,7 +104,7 @@ get_merge_function (uniqstr name, uniqstr type, location loc)
     type = uniqstr_new ("");
 
   head.next = merge_functions;
-  for (syms = &head, n = 1; syms->next != NULL; syms = syms->next, n += 1)
+  for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1)
     if (UNIQSTR_EQ (name, syms->next->name))
       break;
   if (syms->next == NULL)
@@ -127,11 +128,8 @@ get_merge_function (uniqstr name, uniqstr type, location loc)
 void
 free_merger_functions (void)
 {
-  merger_list *L0;
-  if (! glr_parser)
-    return;
-  L0 = merge_functions;
-  while (L0 != NULL)
+  merger_list *L0 = merge_functions;
+  while (L0)
     {
       merger_list *L1 = L0->next;
       free (L0);
@@ -149,20 +147,13 @@ free_merger_functions (void)
 |                                                                    |
 | All actions are copied out, labelled by the rule number they apply |
 | to.                                                                |
-|                                                                    |
-| Bison used to allow some %directives in the rules sections, but    |
-| this is no longer consider appropriate: (i) the documented grammar |
-| doesn't claim it, (ii), it would promote bad style, (iii), error   |
-| recovery for %directives consists in skipping the junk until a `%' |
-| is seen and helrp synchronizing.  This scheme is definitely wrong  |
-| in the rules section.                                              |
 `-------------------------------------------------------------------*/
 
 /* The (currently) last symbol of GRAMMAR. */
 static symbol_list *grammar_end = NULL;
 
 /* Append SYM to the grammar.  */
-void
+static void
 grammar_symbol_append (symbol *sym, location loc)
 {
   symbol_list *p = symbol_list_new (sym, loc);
@@ -173,6 +164,11 @@ grammar_symbol_append (symbol *sym, location loc)
     grammar = p;
 
   grammar_end = p;
+
+  /* A null SYM stands for an end of rule; it is not an actual
+     part of it.  */
+  if (sym)
+    ++nritems;
 }
 
 /* The rule currently being defined, and the previous rule.
@@ -187,7 +183,7 @@ static symbol_list *previous_rule_end = NULL;
 `----------------------------------------------*/
 
 void
-grammar_rule_begin (symbol *lhs, location loc)
+grammar_current_rule_begin (symbol *lhs, location loc)
 {
   if (!start_flag)
     {
@@ -198,14 +194,11 @@ grammar_rule_begin (symbol *lhs, location loc)
 
   /* Start a new rule and record its lhs.  */
   ++nrules;
-  ++nritems;
-
   previous_rule_end = grammar_end;
   grammar_symbol_append (lhs, loc);
   current_rule = grammar_end;
 
   /* Mark the rule's lhs as a nonterminal if not already so.  */
-
   if (lhs->class == unknown_sym)
     {
       lhs->class = nterm_sym;
@@ -216,39 +209,58 @@ grammar_rule_begin (symbol *lhs, location loc)
     complain_at (loc, _("rule given for %s, which is a token"), lhs->tag);
 }
 
-/* Check that the last rule (CURRENT_RULE) is properly defined.  For
-   instance, there should be no type clash on the default action.  */
+
+/*----------------------------------------------------------------.
+| Check that the rule R is properly defined.  For instance, there |
+| should be no type clash on the default action.                  |
+`----------------------------------------------------------------*/
 
 static void
-grammar_current_rule_check (void)
+grammar_rule_check (const symbol_list *r)
 {
-  symbol *lhs = current_rule->sym;
-  char const *lhs_type = lhs->type_name;
-  symbol *first_rhs = current_rule->next->sym;
+  /* Type check.
 
-  /* If there is an action, then there is nothing we can do: the user
-     is allowed to shoot herself in the foot.  */
-  if (current_rule->action)
-    return;
+     If there is an action, then there is nothing we can do: the user
+     is allowed to shoot herself in the foot.
 
-  /* Don't worry about the default action if $$ is untyped, since $$'s
+     Don't worry about the default action if $$ is untyped, since $$'s
      value can't be used.  */
-  if (! lhs_type)
-    return;
-
-  /* If $$ is being set in default way, report if any type mismatch.  */
-  if (first_rhs)
+  if (!r->action && r->sym->type_name)
     {
-      const char *rhs_type = first_rhs->type_name ? first_rhs->type_name : "";
-      if (!UNIQSTR_EQ (lhs_type, rhs_type))
-	warn_at (current_rule->location,
-		 _("type clash on default action: <%s> != <%s>"),
-		 lhs_type, rhs_type);
+      symbol *first_rhs = r->next->sym;
+      /* If $$ is being set in default way, report if any type mismatch.  */
+      if (first_rhs)
+	{
+	  char const *lhs_type = r->sym->type_name;
+	  const char *rhs_type =
+	    first_rhs->type_name ? first_rhs->type_name : "";
+	  if (!UNIQSTR_EQ (lhs_type, rhs_type))
+	    warn_at (r->location,
+		     _("type clash on default action: <%s> != <%s>"),
+		     lhs_type, rhs_type);
+	}
+      /* Warn if there is no default for $$ but we need one.  */
+      else
+	warn_at (r->location,
+		 _("empty rule for typed nonterminal, and no action"));
     }
-  /* Warn if there is no default for $$ but we need one.  */
-  else
-    warn_at (current_rule->location,
-	     _("empty rule for typed nonterminal, and no action"));
+
+  /* Check that typed symbol values are used.  */
+  {
+    symbol_list const *l = r;
+    int n = 0;
+    for (; l && l->sym; l = l->next, ++n)
+      if (! (l->used
+	     || !l->sym->type_name
+	     /* The default action, $$ = $1, `uses' both.  */
+	     || (!r->action && (n == 0 || n == 1))))
+	{
+	  if (n)
+	    warn_at (r->location, _("unused value: $%d"), n);
+	  else
+	    warn_at (r->location, _("unset value: $$"));
+	}
+  }
 }
 
 
@@ -257,12 +269,12 @@ grammar_current_rule_check (void)
 `-------------------------------------*/
 
 void
-grammar_rule_end (location loc)
+grammar_current_rule_end (location loc)
 {
   /* Put an empty link in the list to mark the end of this rule  */
   grammar_symbol_append (NULL, grammar_end->location);
   current_rule->location = loc;
-  grammar_current_rule_check ();
+  grammar_rule_check (current_rule);
 }
 
 
@@ -273,7 +285,7 @@ grammar_rule_end (location loc)
 | rule.                                                              |
 `-------------------------------------------------------------------*/
 
-void
+static void
 grammar_midrule_action (void)
 {
   /* Since the action was written out with this rule's number, we must
@@ -358,7 +370,6 @@ grammar_current_rule_symbol_append (symbol *sym, location loc)
 {
   if (current_rule->action)
     grammar_midrule_action ();
-  ++nritems;
   grammar_symbol_append (sym, loc);
 }
 
@@ -474,8 +485,7 @@ reader (void)
   obstack_init (&pre_prologue_obstack);
   obstack_init (&post_prologue_obstack);
 
-  finput = xfopen (grammar_file, "r");
-  gram_in = finput;
+  gram_in = xfopen (grammar_file, "r");
 
   gram__flex_debug = trace_flag & trace_scan;
   gram_debug = trace_flag & trace_parse;
@@ -523,7 +533,7 @@ reader (void)
   if (! (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars))
     abort ();
 
-  xfclose (finput);
+  xfclose (gram_in);
 
   /* Assign the symbols their symbol numbers.  Write #defines for the
      token symbols into FDEFINES if requested.  */