func (l *Lexer) peek() byte {
	r := l.next()
	l.backup()
	return r
}
// peek returns but does not consume
// the next byte in the input.
peek returns but does not consume
the next byte in the input.
// peek returns but does not consume // the next byte in the input .
func (l *Lexer) peek() byte {
	r := l.next()
	l.backup()
	return r
}
func ( l * Lexer ) peek ( ) byte { r := l . next ( ) l . backup ( ) return r }
peek returns but does not consume
the next byte in the input.
peek returns but does not consume the next byte in the input .