} else {
			curDir = RightToLeft
		}
		if curDir != prevDir {
			if i > 0 {
				o.runes = append(o.runes, runes[prevI:i])
				o.directions = append(o.directions, prevDir)
				o.startpos = append(o.startpos, prevI)
			}
			prevI = i
			prevDir = curDir
		}
	}
	o.runes = append(o.runes, runes[prevI:])
	o.directions = append(o.directions, prevDir)
	o.startpos = append(o.startpos, prevI)
	return o

		partLen = c.Rand.Intn(63) + 1 // len is [1, 63]
	}

	runes := make([]rune, partLen)
	if partLen == 0 {
		return string(runes)
	}

	runes[0] = validStartEnd[c.Rand.Intn(len(validStartEnd))].choose(c.Rand)
	for i := range runes[1:] {
		runes[i+1] = validMiddle[c.Rand.Intn(len(validMiddle))].choose(c.Rand)
	}
	runes[len(runes)-1] = validStartEnd[c.Rand.Intn(len(validStartEnd))].choose(c.Rand)

//	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

	// 	is graphic rune
	// 	is number rune
	// 	is printable rune
	// For 'Ὂ':
	// 	is graphic rune
	// 	is letter rune
	// 	is printable rune
	// 	is upper case rune
	// For 'g':
	// 	is graphic rune
	// 	is letter rune
	// 	is lower case rune
	// 	is printable rune
	// For '̀':
	// 	is graphic rune
	// 	is mark rune
	// 	is printable rune
	// For '9':
	// 	is digit rune
	// 	is graphic rune

	buf := []byte("Hello, 世界")
	fmt.Println("bytes =", len(buf))
	fmt.Println("runes =", utf8.RuneCount(buf))
	// Output:
	// bytes = 13
	// runes = 9
}

func ExampleRuneCountInString() {
	str := "Hello, 世界"
	fmt.Println("bytes =", len(str))
	fmt.Println("runes =", utf8.RuneCountInString(str))
	// Output:
	// bytes = 13
	// runes = 9
}

func ExampleRuneLen() {
	fmt.Println(utf8.RuneLen('a'))

		[]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},

				// is odd so we take the low bit from _case.
				return rune(cr.Lo) + ((r-rune(cr.Lo))&^1 | rune(_case&1)), true
			}
			return r + delta, true
		}
		if r < rune(cr.Lo) {
			hi = m
		} else {
			lo = m + 1
		}
	}
	return r, false
}

// To maps the rune to the specified case: [UpperCase], [LowerCase], or [TitleCase].
func To(_case int, r rune) rune {
	r, _ = to(_case, r, CaseRanges)
	return r
}

		return rune(p0&mask2)<<6 | rune(b1&maskx), 2
	}
	b2 := p[2]
	if b2 < locb || hicb < b2 {
		return RuneError, 1
	}
	if sz <= 3 {
		return rune(p0&mask3)<<12 | rune(b1&maskx)<<6 | rune(b2&maskx), 3
	}
	b3 := p[3]
	if b3 < locb || hicb < b3 {
		return RuneError, 1
	}
	return rune(p0&mask4)<<18 | rune(b1&maskx)<<12 | rune(b2&maskx)<<6 | rune(b3&maskx), 4
}

		}
		// Handle multi-byte Unicode.
		r, n := utf8.DecodeRune(in[i:])
		out = utf8.AppendRune(out, foldRune(r))
		i += n
	}
	return out
}

// foldRune is returns the smallest rune for all runes in the same fold set.
func foldRune(r rune) rune {
	for {
		r2 := unicode.SimpleFold(r)
		if r2 <= r {
			return r2
		}
		r = r2
	}

		}
		t.historyIndex++
		runes := []rune(entry)
		t.setLine(runes, len(runes))
	case keyDown:
		switch t.historyIndex {
		case -1:
			return
		case 0:
			runes := []rune(t.historyPending)
			t.setLine(runes, len(runes))
			t.historyIndex--
		default:
			entry, ok := t.history.NthPreviousEntry(t.historyIndex - 1)
			if ok {
				t.historyIndex--
				runes := []rune(entry)