+};
+
+/* Undefined user number. */
+#define USER_NUMBER_UNDEFINED -1
+
+/* `symbol->user_token_number == USER_NUMBER_ALIAS' means this symbol
+ *has* (not is) a string literal alias. For instance, `%token foo
+ "foo"' has `"foo"' numbered regularly, and `foo' numbered as
+ USER_NUMBER_ALIAS. */
+#define USER_NUMBER_ALIAS -9991
+
+/* Undefined internal token number. */
+#define NUMBER_UNDEFINED ((symbol_number_t) -1)
+
+
+/* Fetch (or create) the symbol associated to KEY. */
+symbol_t *symbol_get (const char *key, location_t location);
+
+/* Generate a dummy nonterminal, whose name cannot conflict with the
+ user's names. */
+symbol_t *dummy_symbol_get (location_t location);
+
+/* Declare the new SYMBOL. Make it an alias of SYMVAL. */
+void symbol_make_alias (symbol_t *symbol, symbol_t *symval,
+ location_t location);
+
+/* Set the TYPE_NAME associated to SYMBOL. Does nothing if passed 0 as
+ TYPE_NAME. */
+void symbol_type_set (symbol_t *symbol,
+ char *type_name, location_t location);
+
+/* Set the DESTRUCTOR associated to SYMBOL. */
+void symbol_destructor_set (symbol_t *symbol,
+ char *destructor, location_t location);
+
+/* Set the PRINTER associated to SYMBOL. */
+void symbol_printer_set (symbol_t *symbol,
+ char *printer, location_t location);
+
+/* Set the PRECEDENCE associated to SYMBOL. Ensures that SYMBOL is a
+ terminal. Does nothing if invoked with UNDEF_ASSOC as ASSOC. */
+void symbol_precedence_set (symbol_t *symbol,
+ int prec, assoc_t assoc, location_t location);
+
+/* Set the CLASS associated to SYMBOL. */
+void symbol_class_set (symbol_t *symbol,
+ symbol_class class, location_t location);
+
+/* Set the USER_TOKEN_NUMBER associated to SYMBOL. */
+void symbol_user_token_number_set (symbol_t *symbol,
+ int user_number, location_t location);
+
+
+/* Distinguished symbols. AXIOM is the real start symbol, that used
+ by the automaton. STARTSYMBOL is the one specified by the user.
+ */
+extern symbol_t *errtoken;
+extern symbol_t *undeftoken;
+extern symbol_t *endtoken;
+extern symbol_t *accept;
+extern symbol_t *startsymbol;
+extern location_t startsymbol_location;
+
+
+/*---------------.
+| Symbol table. |
+`---------------*/
+
+
+/* Create the symbol table. */
+void symbols_new (void);
+
+/* A function to apply to each symbol. */
+typedef bool (*symbol_processor) (symbol_t *);