)

const (
	percent    rune = '%'
	underscore rune = '_'
	runeZero   rune = 0
)

func evalSQLLike(text, pattern string, escape rune) (match bool, err error) {
	s := []rune{}
	prev := runeZero
	hasLeadingPercent := false
	patLen := len([]rune(pattern))
	for i, r := range pattern {
		if i > 0 && prev == escape {
			switch r {

}

// append single byte to scratch buffer
func (s *scratch) add(c byte) {
	if s.fill+1 >= cap(s.data) {
		s.grow()
	}

	s.data[s.fill] = c
	s.fill++
}

// append encoded rune to scratch buffer
func (s *scratch) addRune(r rune) int {
	if s.fill+utf8.UTFMax >= cap(s.data) {
		s.grow()
	}

	n := utf8.EncodeRune(s.data[s.fill:], r)
	s.fill += n
	return n

	return IndexAny(b, chars) >= 0
}

// ContainsRune reports whether the rune is contained in the UTF-8-encoded byte slice b.
func ContainsRune(b []byte, r rune) bool {
	return IndexRune(b, r) >= 0
}

// ContainsFunc reports whether any of the UTF-8-encoded code points r within b satisfy f(r).
func ContainsFunc(b []byte, f func(rune) bool) bool {
	return IndexFunc(b, f) >= 0
}

		ret := csv.NewReader(r)
		ret.Comma = []rune(args.FieldDelimiter)[0]
		ret.Comment = []rune(args.CommentCharacter)[0]
		ret.Quote = []rune{}
		if len([]rune(args.QuoteCharacter)) > 0 {
			// Add the first rune of args.QuoteCharacter
			ret.Quote = append(ret.Quote, []rune(args.QuoteCharacter)[0])
		}
		ret.QuoteEscape = []rune(args.QuoteEscapeCharacter)[0]
		ret.FieldsPerRecord = -1

// converted to int they correspond to the rune size that was read.
type readOp int8

// Don't use iota for these, as the values need to correspond with the
// names and comments, which is easier to see when being explicit.
const (
	opRead      readOp = -1 // Any other read operation.
	opInvalid   readOp = 0  // Non-read operation.
	opReadRune1 readOp = 1  // Read rune of size 1.
	opReadRune2 readOp = 2  // Read rune of size 2.

	if width > 1 {
		// It's a valid encoding. Width cannot be one for a correctly encoded
		// non-ASCII rune.
		return width, data[0:width], nil
	}

	// We know it's an error: we have width==1 and implicitly r==utf8.RuneError.
	// Is the error because there wasn't a full rune to be decoded?
	// FullRune distinguishes correctly between erroneous and incomplete encodings.
	if !atEOF && !utf8.FullRune(data) {

// but without constructing a new slice containing the subslices.
func FieldsSeq(s []byte) iter.Seq[[]byte] {
	return func(yield func([]byte) bool) {
		start := -1
		for i := 0; i < len(s); {
			size := 1
			r := rune(s[i])
			isSpace := asciiSpace[s[i]] != 0
			if r >= utf8.RuneSelf {
				r, size = utf8.DecodeRune(s[i:])
				isSpace = unicode.IsSpace(r)
			}
			if isSpace {
				if start >= 0 {
					if !yield(s[start:i:i]) {

	fmt.Println(bytes.LastIndexFunc([]byte("go gopher!"), unicode.IsNumber))
	// Output:
	// 8
	// 9
	// -1
}

func ExampleMap() {
	rot13 := func(r rune) rune {
		switch {
		case r >= 'A' && r <= 'Z':
			return 'A' + (r-'A'+13)%26
		case r >= 'a' && r <= 'z':
			return 'a' + (r-'a'+13)%26
		}
		return r
	}

	//
	//	R1
	//	offset
	//	$offset
	// Every piece is optional, so we scan left to right and what
	// we discover tells us where we are.

	// Prefix: $.
	var prefix rune
	switch tok := p.peek(); tok {
	case '$', '*':
		prefix = rune(tok)
		p.next()
	}

	// Symbol: sym±offset(SB)
	tok := p.next()
	name := tok.String()
	if tok.ScanToken == scanner.Ident && !p.atStartOfRegister(name) {

		return err
	} else if match {
		return nil
	}

	// normalize the name to letters, digits, _ or $
	valid := true
	cleaned := strings.Map(func(r rune) rune {
		switch {
		case unicode.IsLetter(r):
			return 'a'
		case unicode.IsDigit(r):
			return '0'
		case r == '_', r == '$':
			return r
		default:
			valid = false
			return -1
		}