// delimiters; it returns false otherwise.
func (tok Token) IsOperator() bool {
	return (operator_beg < tok && tok < operator_end) || tok == TILDE
}

// IsKeyword returns true for tokens corresponding to keywords;
// it returns false otherwise.
func (tok Token) IsKeyword() bool { return keyword_beg < tok && tok < keyword_end }

// IsExported reports whether name starts with an upper-case letter.
func IsExported(name string) bool {