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
	}

	r.i--
	return nil
}

// ReadRune implements the [io.RuneReader] interface.
func (r *Reader) ReadRune() (ch rune, size int, err error) {
	if r.i >= int64(len(r.s)) {
		r.prevRune = -1
		return 0, 0, io.EOF
	}
	r.prevRune = int(r.i)
	if c := r.s[r.i]; c < utf8.RuneSelf {
		r.i++
		return rune(c), 1, nil
	}
	ch, size = utf8.DecodeRune(r.s[r.i:])
	r.i += int64(size)
	return
}

		}
	}
}

// FieldsFuncSeq returns an iterator over subslices of s split around runs of
// Unicode code points satisfying f(c).
// The iterator yields the same subslices that would be returned by [FieldsFunc](s),
// but without constructing a new slice containing the subslices.
func FieldsFuncSeq(s []byte, f func(rune) bool) iter.Seq[[]byte] {
	return func(yield func([]byte) bool) {
		start := -1

	//
	//	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) {

		line: 1,
		file: file,
	}
}

// We want center dot (·) and division slash (∕) to work as identifier characters.
func isIdentRune(ch rune, i int) bool {
	if unicode.IsLetter(ch) {
		return true
	}
	switch ch {
	case '_': // Underscore; traditional.
		return true
	case '\u00B7': // Represents the period in runtime.exit. U+00B7 '·' middle dot

		}
	}
}

// Test that the rune splitter returns same sequence of runes (not bytes) as for range string.
func TestScanRune(t *testing.T) {
	for n, test := range scanTests {
		buf := strings.NewReader(test)
		s := NewScanner(buf)
		s.Split(ScanRunes)
		var i, runeCount int
		var expect rune
		// Use a string range loop to validate the sequence of runes.
		for i, expect = range test {
			if !s.Scan() {

		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
		}

func FileWithLineNum() string {
	frame := CallerFrame()
	if frame.PC != 0 {
		return string(strconv.AppendInt(append([]byte(frame.File), ':'), int64(frame.Line), 10))
	}

	return ""
}

func IsInvalidDBNameChar(c rune) bool {
	return !unicode.IsLetter(c) && !unicode.IsNumber(c) && c != '.' && c != '*' && c != '_' && c != '$' && c != '@'
}

// CheckTruth check string true or not
func CheckTruth(vals ...string) bool {

import (
	"testing"
)

func TestNewRequestID(t *testing.T) {
	// Ensure that it returns an alphanumeric result of length 16.
	id := mustGetRequestID(UTCNow())

	if len(id) != 16 {
		t.Fail()
	}

	var e rune
	for _, char := range id {
		e = char

		// Ensure that it is alphanumeric, in this case, between 0-9 and A-Z.
		isAlnum := ('0' <= e && e <= '9') || ('A' <= e && e <= 'Z')
		if !isAlnum {
			t.Fail()
		}
	}

			comment: "in the 世界",
			flags:   0x808,
		},
		{
			name:    "hi, こんにちわ",
			comment: "in the 世界",
			flags:   0x808,
		},
		{
			name:    "the replacement rune is �",
			comment: "the replacement rune is �",
			flags:   0x808,
		},
		{
			// Name is Japanese encoded in Shift JIS.
			name:    "\x93\xfa\x96{\x8c\xea.txt",
			comment: "in the 世界",