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/symtab.h

@@ -30,6 +30,7 @@
 
 # include "assoc.h"
 # include "location.h"
+# include "scan-code.h"
 # include "uniqstr.h"
 
 /*----------.
@@ -72,25 +73,13 @@ struct symbol
      example, if <tt>symbol::destructor = NULL</tt>, a default \c \%destructor
      or a per-type \c \%destructor might be appropriate, and
      \c symbol_destructor_get will compute the correct one.  */
-  const char *destructor;
-
-  /** The location of \c symbol::destructor.
-
-     Access this field only through <tt>symbol</tt>'s interface functions.
-     \sa symbol::destructor  */
-  location destructor_location;
+  code_props destructor;
 
   /** Any \c \%printer declared specifically for this symbol.
 
      Access this field only through <tt>symbol</tt>'s interface functions.
      \sa symbol::destructor  */
-  const char *printer;
-
-  /** The location of \c symbol::printer.
-
-     Access this field only through <tt>symbol</tt>'s interface functions.
-     \sa symbol::destructor  */
-  location printer_location;
+  code_props printer;
 
   symbol_number number;
   location prec_location;
@@ -144,26 +133,18 @@ void symbol_make_alias (symbol *sym, symbol *symval, location loc);
 void symbol_type_set (symbol *sym, uniqstr type_name, location loc);
 
 /** Set the \c destructor associated with \c sym.  */
-void symbol_destructor_set (symbol *sym, const char *destructor, location loc);
+void symbol_destructor_set (symbol *sym, code_props destructor);
 
-/** Get the computed \c \%destructor for \c sym, or \c NULL if none.   */
-const char *symbol_destructor_get (symbol *sym);
-
-/** Get the grammar location of the computed \c \%destructor for \c sym.
- 
-  \pre <tt>symbol_destructor_get (sym) != NULL</tt> */
-location symbol_destructor_location_get (symbol *sym);
+/** Get the computed \c \%destructor for \c sym, which was initialized with
+    \c code_props_none_init if there's no \c \%destructor.  */
+code_props symbol_destructor_get (symbol *sym);
 
 /** Set the \c printer associated with \c sym.  */
-void symbol_printer_set (symbol *sym, const char *printer, location loc);
+void symbol_printer_set (symbol *sym, code_props printer);
 
-/** Get the computed \c \%printer for \c sym, or \c NULL if none.  */
-const char *symbol_printer_get (symbol *sym);
-
-/** Get the grammar location of the computed \c \%printer for \c sym.
-
-  \pre <tt>symbol_printer_get (sym) != NULL</tt> */
-location symbol_printer_location_get (symbol *sym);
+/** Get the computed \c \%printer for \c sym, which was initialized with
+    \c code_props_none_init if there's no \c \%printer.  */
+code_props symbol_printer_get (symbol *sym);
 
 /* Set the \c precedence associated with \c sym.
 
@@ -209,14 +190,9 @@ typedef struct semantic_type {
   uniqstr tag;
 
   /** Any \c %destructor declared for this semantic type.  */
-  const char *destructor;
-  /** The location of \c semantic_type::destructor.  */
-  location destructor_location;
-
+  code_props destructor;
   /** Any \c %printer declared for this semantic type.  */
-  const char *printer;
-  /** The location of \c semantic_type::printer.  */
-  location printer_location;
+  code_props printer;
 } semantic_type;
 
 /** Fetch (or create) the semantic type associated to KEY.  */
@@ -226,12 +202,10 @@ semantic_type *semantic_type_from_uniqstr (const uniqstr key);
 semantic_type *semantic_type_get (const char *key);
 
 /** Set the \c destructor associated with \c type.  */
-void semantic_type_destructor_set (semantic_type *type, const char *destructor,
-                                   location loc);
+void semantic_type_destructor_set (semantic_type *type, code_props destructor);
 
 /** Set the \c printer associated with \c type.  */
-void semantic_type_printer_set (semantic_type *type, const char *printer,
-                                location loc);
+void semantic_type_printer_set (semantic_type *type, code_props printer);
 
 /*----------------------------------.
 | Symbol and semantic type tables.  |
@@ -260,13 +234,13 @@ void symbols_pack (void);
 `---------------------------------------*/
 
 /** Set the default \c \%destructor for tagged values.  */
-void default_tagged_destructor_set (const char *destructor, location loc);
+void default_tagged_destructor_set (code_props destructor);
 /** Set the default \c \%destructor for tagless values.  */
-void default_tagless_destructor_set (const char *destructor, location loc);
+void default_tagless_destructor_set (code_props destructor);
 
 /** Set the default \c \%printer for tagged values.  */
-void default_tagged_printer_set (const char *printer, location loc);
+void default_tagged_printer_set (code_props printer);
 /** Set the default \c \%printer for tagless values.  */
-void default_tagless_printer_set (const char *printer, location loc);
+void default_tagless_printer_set (code_props printer);
 
 #endif /* !SYMTAB_H_ */