"strings"
	"text/scanner"

	"cmd/internal/src"
)

// A ScanToken represents an input item. It is a simple wrapping of rune, as
// returned by text/scanner.Scanner, plus a couple of extra values.
type ScanToken rune

const (
	// Asm defines some two-character lexemes. We make up
	// a rune/ScanToken value for them - ugly but simple.
	LSH          ScanToken = -1000 - iota // << Left shift.

	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
}

	}
}

func bmIndexRuneUnicode(rt *unicode.RangeTable, needle rune) func(b *testing.B, n int) {
	var rs []rune
	for _, r16 := range rt.R16 {
		for r := rune(r16.Lo); r <= rune(r16.Hi); r += rune(r16.Stride) {
			if r != needle {
				rs = append(rs, r)
			}
		}
	}
	for _, r32 := range rt.R32 {
		for r := rune(r32.Lo); r <= rune(r32.Hi); r += rune(r32.Stride) {
			if r != needle {
				rs = append(rs, r)
			}

var m map[string]int

var chanVar chan int

var ifaceVar any = 5

var assertVar = ifaceVar.(int)

var indexVar = m["foo"]

var Byte byte
var ByteFunc func(byte) rune

type ByteStruct struct {
	B byte
	R rune

// 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]) {

// 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) {

	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
}

	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) {