void expr_list(void)
{
	/* <expr_list>		-> <expression> #write_expr
	 * 				{, <expression> #write_expr}
	 */
	expr_rec out_expr;

	expression(&out_expr);
	write_expr(out_expr);

	while (next_token() == COMMA) {
		match(COMMA);
		expression(&out_expr);
		write_expr(out_expr);
	}
}