Encapsulate code properties and related functionality for the various

destructors, printers, and actions into a code_props structure and
interface.
* src/location.h (EMPTY_LOCATION_INIT): Define so that it's easier to
consistently initialize const structs that have an empty location field.
* src/location.c (empty_location): Initialize with EMPTY_LOCATION_INIT
to ensure consistency.
* src/output.c (symbol_destructors_output, symbol_printers_output):
Replace with...
(symbol_code_props_output): ... this to eliminate duplicate code.
(output_skeleton): Update to use symbol_code_props_output.
* src/parse-gram.y (prologue_declaration, braceless, epilogue.opt):
Update all uses of translate_* functions to use the new code_props
interface and to use gram_scanner_last_string_free and
code_scanner_last_string_free where possible.
(grammar_declaration): symbol_list_destructor_set and
symbol_list_printer_set now perform the translation, so don't do it
here.  Use gram_scanner_last_string_free where possible.
* src/reader.c: Update to use code_props interface for destructors and
rule actions.
* src/scan-code.h (code_props): New structure.
(code_props_none_init, CODE_PROPS_NONE_INIT, code_props_none): New
function, macro, and const global variable for initializing a
code_props with no code.
(code_props_plain_init, code_props_symbol_action_init,
code_props_rule_action_init, code_props_translate_code,
code_props_code_get, code_props_location_get,
code_props_is_value_used): The rest of the new code_props interface.
(translate_rule_action, translate_symbol_action, translate_code):
Remove as these are now just special cases within
code_props_translate_code, which is switched on the code_props kind.
(code_scanner_last_string_free): New function similar to
gram_scanner_last_string_free.
* src/scan-code.l: Implement the new interface.
(last_string): New static global similar to the one in scan-gram.l.
(SC_SYMBOL_ACTION): For $$, set the is_value_used member of the
code_props since Bison will one day use this information for
destructors and printers.
(<*><<EOF>>): Use STRING_FINISH so that last_string is set.
(handle_action_dollar): Update to use the code_props interface of rule
actions.  Use symbol_list_n_get and set is_value_used directly since
symbol_list_n_used_set is removed.
* src/symlist.h, src/symlist.c (symbol_list): Replace action,
action_location, and used members with a code_props member, and update
all uses.
(symbol_list_n_used_set): Remove since it would need to break the
encapsulation of code_props.
(symbol_list_destructor_set, symbol_list_printer_set): Perform code
translation here rather than depending on the caller to do so.
* src/symtab.h (symbol, semantic_type): Remove destructor_location and
printer_location members and change the type of the destructor and
printer members to code_props.
(symbol_destructor_location_get, symbol_printer_location_get): Remove
unneeded.
(symbol_destructor_set, symbol_destructor_get, symbol_printer_set,
symbol_printer_get, semantic_type_destructor_set,
semantic_type_printer_set, default_tagged_destructor_set,
default_tagless_destructor_set, default_tagged_printer_set,
default_tagless_printer_set): Use code_props in arguments and return
types in place of const char * and location.
* src/symtab.c: Update implementation for interface and struct changes.
(default_tagged_destructor_location,
default_tagless_destructor_location, default_tagged_printer_location,
default_tagless_printer_location): Remove since we...
(default_tagged_destructor, default_tagless_destructor,
default_tagged_printer, default_tagless_printer): ... change the type
of these to code_props.
(SYMBOL_CODE_PRINT): New similar to SYMBOL_ATTR_PRINT but for
code_props members.
(symbol_print): Use SYMBOL_CODE_PRINT.

* src/scan-gram.h (gram_last_string): Remove declaration.
* src/scan-gram.l (last_string): Declare it static.

src/symlist.c

@@ -23,6 +23,7 @@
 #include "system.h"
 
 #include "complain.h"
+#include "scan-code.h"
 #include "symlist.h"
 
 
@@ -43,8 +44,7 @@ symbol_list_sym_new (symbol *sym, location loc)
   res->midrule_parent_rule = NULL;
   res->midrule_parent_rhs_index = 0;
 
-  res->action = NULL;
-  res->used = false;
+  code_props_none_init (&res->action_props);
 
   res->ruleprec = NULL;
   res->dprec = 0;
@@ -118,7 +118,9 @@ symbol_list_syms_print (const symbol_list *l, FILE *f)
   for (/* Nothing. */; l && l->content.sym; l = l->next)
     {
       symbol_print (l->content.sym, f);
-      fprintf (stderr, l->used ? " used" : " unused");
+      fprintf (stderr,
+               code_props_is_value_used (l->action_props)
+               ? " used" : " unused");
       if (l && l->content.sym)
 	fprintf (f, ", ");
     }
@@ -207,57 +209,50 @@ symbol_list_n_type_name_get (symbol_list *l, location loc, int n)
 }
 
 
-/*--------------------------------------.
-| The item N in symbol list L is USED.  |
-`--------------------------------------*/
-
 void
-symbol_list_n_used_set (symbol_list *l, int n, bool used)
-{
-  l = symbol_list_n_get (l, n);
-  if (l)
-    l->used = used;
-}
-
-void
-symbol_list_destructor_set (symbol_list *node, const char *destructor,
-                            location loc)
+symbol_list_destructor_set (symbol_list *node, const char *code, location loc)
 {
+  code_props destructor;
+  code_props_symbol_action_init (&destructor, code, loc);
+  code_props_translate_code (&destructor);
   switch (node->content_type)
     {
       case SYMLIST_SYMBOL:
-        symbol_destructor_set (node->content.sym, destructor, loc);
+        symbol_destructor_set (node->content.sym, destructor);
         break;
       case SYMLIST_TYPE:
         semantic_type_destructor_set (
-          semantic_type_get (node->content.type_name), destructor, loc);
+          semantic_type_get (node->content.type_name), destructor);
         break;
       case SYMLIST_DEFAULT_TAGGED:
-        default_tagged_destructor_set (destructor, loc);
+        default_tagged_destructor_set (destructor);
         break;
       case SYMLIST_DEFAULT_TAGLESS:
-        default_tagless_destructor_set (destructor, loc);
+        default_tagless_destructor_set (destructor);
         break;
     }
 }
 
 void
-symbol_list_printer_set (symbol_list *node, const char *printer, location loc)
+symbol_list_printer_set (symbol_list *node, const char *code, location loc)
 {
+  code_props printer;
+  code_props_symbol_action_init (&printer, code, loc);
+  code_props_translate_code (&printer);
   switch (node->content_type)
     {
       case SYMLIST_SYMBOL:
-        symbol_printer_set (node->content.sym, printer, loc);
+        symbol_printer_set (node->content.sym, printer);
         break;
       case SYMLIST_TYPE:
         semantic_type_printer_set (
-          semantic_type_get (node->content.type_name), printer, loc);
+          semantic_type_get (node->content.type_name), printer);
         break;
       case SYMLIST_DEFAULT_TAGGED:
-        default_tagged_printer_set (printer, loc);
+        default_tagged_printer_set (printer);
         break;
       case SYMLIST_DEFAULT_TAGLESS:
-        default_tagless_printer_set (printer, loc);
+        default_tagless_printer_set (printer);
         break;
     }
 }