case InstNop:
		bw(b, "nop -> ", u32(i.Out))
	case InstRune:
		if i.Rune == nil {
			// shouldn't happen
			bw(b, "rune <nil>")
		}
		bw(b, "rune ", strconv.QuoteToASCII(string(i.Rune)))
		if Flags(i.Arg)&FoldCase != 0 {
			bw(b, "/i")
		}
		bw(b, " -> ", u32(i.Out))
	case InstRune1:
		bw(b, "rune1 ", strconv.QuoteToASCII(string(i.Rune)), " -> ", u32(i.Out))
	case InstRuneAny:
		bw(b, "any -> ", u32(i.Out))

//	2..0  case mode
//
// For the non-exceptional cases, a rune must be either uncased, lowercase or
// uppercase. If the rune is cased, the XOR pattern maps either a lowercase
// rune to uppercase or an uppercase rune to lowercase (applied to the 10
// least-significant bits of the rune).
//
// See the definitions below for a more detailed description of the various
// bits.
type info uint16

		[]rune{69, 74},
		[]rune{65, 69},
		[]rune{},
		[]uint32{mergeFailed},
		1, 2,
	},
	{
		// overlap from above
		[]rune{69, 74},
		[]rune{71, 74},
		[]rune{},
		[]uint32{mergeFailed},
		1, 2,
	},
	{
		// overlap from below
		[]rune{69, 74},
		[]rune{65, 71},
		[]rune{},
		[]uint32{mergeFailed},
		1, 2,
	},
	{
		// out of order []rune
		[]rune{69, 74, 60, 65},

		fmt.Fprintf(&buf, "\t%#04x,\n", r-0x10000)
	}
	fmt.Fprintf(&buf, "}\n\n")

	// The list of graphic but not "printable" runes is short. Just make one easy table.
	fmt.Fprintf(&buf, "// isGraphic lists the graphic runes not matched by IsPrint.\n")
	fmt.Fprintf(&buf, "var isGraphic = []uint16{\n")
	for r := rune(0); r <= unicode.MaxRune; r++ {
		if unicode.IsPrint(r) != unicode.IsGraphic(r) {
			// Sanity check.

func (p Properties) CCC() uint8 {
	if p.index >= firstCCCZeroExcept {
		return 0
	}
	return ccc[p.ccc]
}

// LeadCCC returns the CCC of the first rune in the decomposition.
// If there is no decomposition, LeadCCC equals CCC.
func (p Properties) LeadCCC() uint8 {
	return ccc[p.ccc]
}

// TrailCCC returns the CCC of the last rune in the decomposition.

func Decode(s []uint16) []rune {
	// Preallocate capacity to hold up to 64 runes.
	// Decode inlines, so the allocation can live on the stack.
	buf := make([]rune, 0, 64)
	return decode(s, buf)
}

// decode appends to buf the Unicode code point sequence represented
// by the UTF-16 encoding s and return the extended buffer.
func decode(s []uint16, buf []rune) []rune {
	for i := 0; i < len(s); i++ {

// is undesirable for our purposes. ICU prevents breaks in such cases as well.

// isBreak returns whether this rune should introduce a break.
func (c info) isBreak() bool {
	return c.cccVal() == cccBreak
}

// isLetter returns whether the rune is of break type ALetter, Hebrew_Letter,
// Numeric, ExtendNumLet, or Extend.
func (c info) isLetter() bool {
	ccc := c.cccVal()
	if ccc == cccZero {

//
//	q := strconv.Quote("Hello, 世界")
//	q := strconv.QuoteToASCII("Hello, 世界")
//
// [QuoteRune] and [QuoteRuneToASCII] are similar but accept runes and
// return quoted Go rune literals.
//
// [Unquote] and [UnquoteChar] unquote Go string and rune literals.

// unbounded lookahead is needed for cased runes.
type context struct {
	dst, src []byte
	atEOF    bool

	pDst int // pDst points past the last written rune in dst.
	pSrc int // pSrc points to the start of the currently scanned rune.

	// checkpoints safe to return in Transform, where nDst <= pDst and nSrc <= pSrc.
	nDst, nSrc int
	err        error

	sz   int  // size of current rune

	}
	// The open bracket must be preceeded by a link-adjacent rune (or by nothing).
	if t := plainText(i - 1); t != "" {
		r, _ := utf8.DecodeLastRuneInString(t)
		if !isLinkAdjacentRune(r) {
			return ""
		}
	}
	// The element after the next must be a ']'.
	if plainText(i+2) != "]" {
		return ""
	}
	// The ']' must be followed by a link-adjacent rune (or by nothing).
	if t := plainText(i + 3); t != "" {