Re: %union ... {

[Akim Demaille]

>>> "Paul" == Paul Eggert <address@hidden> writes:

 > Doesn't this invoke uniqstr_new on the same symbol twice?  Once by the
 > scanner, and once by the parser.  Admittedly hashing is not the
 > biggest overhead in Bison, but still it's a bit weird that we
 > immediately look up the same symbol twice in the same table.

Sure.  I refrained from this because there is no overloading in C, so
it widens the interface, but not by much.

Index: ChangeLog
from  Akim Demaille  <address@hidden>

        * src/symtab.h, src/symtab.c (symbol_from_uniqstr): New.
        (symbol_get): Use it.
        * src/parse-gram.y: Use it.

Index: src/parse-gram.y
===================================================================
RCS file: /cvsroot/bison/bison/src/parse-gram.y,v
retrieving revision 1.77
diff -u -u -r1.77 parse-gram.y
--- src/parse-gram.y 19 Jun 2006 21:32:40 -0000 1.77
+++ src/parse-gram.y 20 Jun 2006 11:32:45 -0000
@@ -463,7 +463,7 @@

 id:
   ID
-    { $$ = symbol_get ($1, @1); }
+    { $$ = symbol_from_uniqstr ($1, @1); }
 | CHAR
     {
       $$ = symbol_get (char_name ($1), @1);
@@ -473,7 +473,7 @@
 ;

 id_colon:
-  ID_COLON { $$ = symbol_get ($1, @1); }
+  ID_COLON { $$ = symbol_from_uniqstr ($1, @1); }
 ;


Index: src/symtab.c
===================================================================
RCS file: /cvsroot/bison/bison/src/symtab.c,v
retrieving revision 1.70
diff -u -u -r1.70 symtab.c
--- src/symtab.c 21 Jan 2006 04:35:09 -0000 1.70
+++ src/symtab.c 20 Jun 2006 11:32:45 -0000
@@ -499,12 +499,11 @@
 `----------------------------------------------------------------*/

 symbol *
-symbol_get (const char *key, location loc)
+symbol_from_uniqstr (const uniqstr key, location loc)
 {
   symbol probe;
   symbol *entry;

-  key = uniqstr_new (key);
   probe.tag = key;
   entry = hash_lookup (symbol_table, &probe);

@@ -518,6 +517,18 @@
 }


+/*----------------------------------------------------------------.
+| Find the symbol named KEY, and return it.  If it does not exist |
+| yet, create it.                                                 |
+`----------------------------------------------------------------*/
+
+symbol *
+symbol_get (const char *key, location loc)
+{
+  return symbol_from_uniqstr (uniqstr_new (key), loc);
+}
+
+
 /*------------------------------------------------------------------.
 | Generate a dummy nonterminal, whose name cannot conflict with the |
 | user's names.                                                     |
Index: src/symtab.h
===================================================================
RCS file: /cvsroot/bison/bison/src/symtab.h,v
retrieving revision 1.59
diff -u -u -r1.59 symtab.h
--- src/symtab.h 3 Jan 2006 21:31:57 -0000 1.59
+++ src/symtab.h 20 Jun 2006 11:32:45 -0000
@@ -98,6 +98,9 @@
 void symbol_print (symbol *s, FILE *f);

 /* Fetch (or create) the symbol associated to KEY.  */
+symbol *symbol_from_uniqstr (const uniqstr key, location loc);
+
+/* Fetch (or create) the symbol associated to KEY.  */
 symbol *symbol_get (const char *key, location loc);

 /* Generate a dummy nonterminal, whose name cannot conflict with the