func (x *Lexer) peek() rune {
	if x.pos >= len(x.input) {
		return eof
	}
	r, _ := utf8.DecodeRune(x.input[x.pos:])
	return r
}
// peek returns, but does not consume, the next rune from the input.
peek returns, but does not consume, the next rune from the input.
// peek returns but does not consume the next rune from the input .
func (x *Lexer) peek() rune {
	if x.pos >= len(x.input) {
		return eof
	}
	r, _ := utf8.DecodeRune(x.input[x.pos:])
	return r
}
func ( x * Lexer ) peek ( ) rune { if x . pos >= len ( x . input ) { return eof } r , _ := utf8 . DecodeRune ( x . input [ x . pos : ] ) return r }
peek returns, but does not consume, the next rune from the input.
peek returns but does not consume the next rune from the input .