+#define NUMBER_UNDEFINED (-1)
+
+
+/* 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
+ user's names. */
+symbol *dummy_symbol_get (location loc);
+
+/* Declare the new symbol SYM. Make it an alias of SYMVAL. */
+void symbol_make_alias (symbol *sym, symbol *symval, location loc);
+
+/* Set the TYPE_NAME associated with SYM. Do nothing if passed 0 as
+ TYPE_NAME. */
+void symbol_type_set (symbol *sym, uniqstr type_name, location loc);
+
+/* Set the DESTRUCTOR associated with SYM. */
+void symbol_destructor_set (symbol *sym, char *destructor, location loc);
+
+/* Set the PRINTER associated with SYM. */
+void symbol_printer_set (symbol *sym, char *printer, location loc);
+
+/* Set the PRECEDENCE associated with SYM. Ensure that SYMBOL is a
+ terminal. Do nothing if invoked with UNDEF_ASSOC as ASSOC. */
+void symbol_precedence_set (symbol *sym, int prec, assoc a, location loc);
+
+/* Set the CLASS associated with SYM. */
+void symbol_class_set (symbol *sym, symbol_class class, location loc);
+
+/* Set the USER_TOKEN_NUMBER associated with SYM. */
+void symbol_user_token_number_set (symbol *sym, int user_number, location loc);
+
+
+/* Distinguished symbols. AXIOM is the real start symbol, that used
+ by the automaton. STARTSYMBOL is the one specified by the user.
+ */
+extern symbol *errtoken;
+extern symbol *undeftoken;
+extern symbol *endtoken;
+extern symbol *accept;
+extern symbol *startsymbol;
+extern location startsymbol_location;
+
+
+/*---------------.
+| Symbol table. |
+`---------------*/
+