+/*---------------------------------------.
+| Default %destructor's and %printer's. |
+`---------------------------------------*/
+
+static code_props default_tagged_destructor = CODE_PROPS_NONE_INIT;
+static code_props default_tagless_destructor = CODE_PROPS_NONE_INIT;
+static code_props default_tagged_printer = CODE_PROPS_NONE_INIT;
+static code_props default_tagless_printer = CODE_PROPS_NONE_INIT;
+
+/*---------------------------------.
+| Create a new symbol, named TAG. |
+`---------------------------------*/
+
+static symbol *
+symbol_new (uniqstr tag, location loc)
+{
+ symbol *res = xmalloc (sizeof *res);
+
+ uniqstr_assert (tag);
+
+ /* If the tag is not a string (starts with a double quote), check
+ that it is valid for Yacc. */
+ if (tag[0] != '\"' && tag[0] != '\'' && strchr (tag, '-'))
+ yacc_at (loc, _("POSIX Yacc forbids dashes in symbol names: %s"),
+ tag);
+
+ res->tag = tag;
+ res->location = loc;
+
+ res->type_name = NULL;
+ code_props_none_init (&res->destructor);
+ code_props_none_init (&res->printer);
+
+ res->number = NUMBER_UNDEFINED;
+ res->prec = 0;
+ res->assoc = undef_assoc;
+ res->user_token_number = USER_NUMBER_UNDEFINED;
+
+ res->alias = NULL;
+ res->class = unknown_sym;
+ res->declared = false;
+
+ if (nsyms == SYMBOL_NUMBER_MAXIMUM)
+ fatal (_("too many symbols in input grammar (limit is %d)"),
+ SYMBOL_NUMBER_MAXIMUM);
+ nsyms++;
+ return res;
+}
+
+/*----------------------------------------.
+| Create a new semantic type, named TAG. |
+`----------------------------------------*/
+
+static semantic_type *
+semantic_type_new (uniqstr tag)
+{
+ semantic_type *res = xmalloc (sizeof *res);
+
+ uniqstr_assert (tag);
+ res->tag = tag;
+ code_props_none_init (&res->destructor);
+ code_props_none_init (&res->printer);
+
+ return res;
+}
+
+
+/*-----------------.
+| Print a symbol. |
+`-----------------*/
+
+#define SYMBOL_ATTR_PRINT(Attr) \
+ if (s->Attr) \
+ fprintf (f, " %s { %s }", #Attr, s->Attr)
+
+#define SYMBOL_CODE_PRINT(Attr) \
+ if (s->Attr.code) \
+ fprintf (f, " %s { %s }", #Attr, s->Attr.code)
+
+void
+symbol_print (symbol *s, FILE *f)
+{
+ if (s)
+ {
+ fprintf (f, "\"%s\"", s->tag);
+ SYMBOL_ATTR_PRINT (type_name);
+ SYMBOL_CODE_PRINT (destructor);
+ SYMBOL_CODE_PRINT (printer);
+ }
+ else
+ fprintf (f, "<NULL>");
+}
+
+#undef SYMBOL_ATTR_PRINT
+#undef SYMBOL_CODE_PRINT
+
+
+/*----------------------------------.
+| Whether S is a valid identifier. |
+`----------------------------------*/
+
+static bool
+is_identifier (uniqstr s)
+{
+ static char const alphanum[26 + 26 + 1 + 10] =
+ "abcdefghijklmnopqrstuvwxyz"
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+ "_"
+ "0123456789";
+ if (!s || ! memchr (alphanum, *s, sizeof alphanum - 10))
+ return false;
+ for (++s; *s; ++s)
+ if (! memchr (alphanum, *s, sizeof alphanum))
+ return false;
+ return true;
+}
+
+
+/*-----------------------------------------------.
+| Get the identifier associated to this symbol. |
+`-----------------------------------------------*/
+uniqstr
+symbol_id_get (symbol const *sym)
+{
+ aver (sym->user_token_number != USER_NUMBER_HAS_STRING_ALIAS);
+ if (sym->alias)
+ sym = sym->alias;
+ return is_identifier (sym->tag) ? sym->tag : 0;
+}
+
+
+/*------------------------------------------------------------------.
+| Complain that S's WHAT is redeclared at SECOND, and was first set |
+| at FIRST. |
+`------------------------------------------------------------------*/
+
+static void
+symbol_redeclaration (symbol *s, const char *what, location first,
+ location second)
+{
+ complain_at (second, _("%s redeclaration for %s"), what, s->tag);
+ complain_at (first, _("previous declaration"));
+}
+
+static void
+semantic_type_redeclaration (semantic_type *s, const char *what, location first,
+ location second)
+{
+ complain_at (second, _("%s redeclaration for <%s>"), what, s->tag);
+ complain_at (first, _("previous declaration"));
+}
+
+
+
+/*-----------------------------------------------------------------.
+| Set the TYPE_NAME associated with SYM. Does nothing if passed 0 |
+| as TYPE_NAME. |
+`-----------------------------------------------------------------*/
+
+void
+symbol_type_set (symbol *sym, uniqstr type_name, location loc)
+{
+ if (type_name)
+ {
+ if (sym->type_name)
+ symbol_redeclaration (sym, "%type", sym->type_location, loc);
+ uniqstr_assert (type_name);
+ sym->type_name = type_name;
+ sym->type_location = loc;
+ }
+}
+
+/*-----------------------------------------.
+| Set the DESTRUCTOR associated with SYM. |
+`-----------------------------------------*/
+
+void
+symbol_destructor_set (symbol *sym, code_props const *destructor)
+{
+ if (sym->destructor.code)
+ symbol_redeclaration (sym, "%destructor", sym->destructor.location,
+ destructor->location);
+ sym->destructor = *destructor;
+}
+
+/*------------------------------------------.
+| Set the DESTRUCTOR associated with TYPE. |
+`------------------------------------------*/
+
+void
+semantic_type_destructor_set (semantic_type *type,
+ code_props const *destructor)
+{
+ if (type->destructor.code)
+ semantic_type_redeclaration (type, "%destructor",
+ type->destructor.location,
+ destructor->location);
+ type->destructor = *destructor;
+}
+
+/*---------------------------------------.
+| Get the computed %destructor for SYM. |
+`---------------------------------------*/
+
+code_props const *
+symbol_destructor_get (symbol const *sym)
+{
+ /* Per-symbol %destructor. */
+ if (sym->destructor.code)
+ return &sym->destructor;
+
+ /* Per-type %destructor. */
+ if (sym->type_name)
+ {
+ code_props const *destructor =
+ &semantic_type_get (sym->type_name)->destructor;
+ if (destructor->code)
+ return destructor;
+ }
+
+ /* Apply default %destructor's only to user-defined symbols. */
+ if (sym->tag[0] == '$' || sym == errtoken)
+ return &code_props_none;
+
+ if (sym->type_name)
+ return &default_tagged_destructor;
+ return &default_tagless_destructor;
+}
+
+/*--------------------------------------.
+| Set the PRINTER associated with SYM. |
+`--------------------------------------*/
+
+void
+symbol_printer_set (symbol *sym, code_props const *printer)