     parse_shorts : parse_shorts
     parse_args   : parse_args
     printable_usage: printable_usage
-

    result = []
    if token is '('
        tokens.shift()
        
        result = [new Required parse_expr tokens, options]
        if tokens.shift() != ')'
            raise tokens.error "Unmatched '('"

            if not matched
                return [false, left, collected]
        [true, l, c]


class Optional extends Pattern

