+ Ensure that \a symbol is a terminal.
+ Do nothing if invoked with \c undef_assoc as \c assoc. */
+void symbol_precedence_set (symbol *sym, int prec, assoc a, location loc);
+
+/** Set the \c class associated with \c sym. */
+void symbol_class_set (symbol *sym, symbol_class class, location loc,
+ bool declaring);
+
+/** Set the \c user_token_number associated with \c sym. */
+void symbol_user_token_number_set (symbol *sym, int user_number, location loc);
+
+
+/** The error token. */
+extern symbol *errtoken;
+/** The token for unknown tokens. */
+extern symbol *undeftoken;
+/** The end of input token. */
+extern symbol *endtoken;
+/** The genuine start symbol.
+
+ $accept: start-symbol $end */
+extern symbol *accept;
+
+/** The user start symbol. */
+extern symbol *startsymbol;
+/** The location of the \c \%start declaration. */
+extern location startsymbol_location;
+
+
+/*-----------------.
+| Semantic types. |
+`-----------------*/