// written, not just their values. Particularly useful for runes.
func f8(r rune) {
	const x = 10
	switch r {
	case 33, 33: // ERROR "duplicate case (33 in switch)?"
	case 34, '"': // ERROR "duplicate case '"' .value 34. in switch"
	case 35, rune('#'): // ERROR "duplicate case (rune.'#'. .value 35. in switch)?"
	case 36, rune(36): // ERROR "duplicate case (rune.36. .value 36. in switch)?"

package mime

import (
	"strings"
)

// isTSpecial reports whether rune is in 'tspecials' as defined by RFC
// 1521 and RFC 2045.
func isTSpecial(r rune) bool {
	return strings.ContainsRune(`()<>@,;:\"/[]?=`, r)
}

// isTokenChar reports whether rune is in 'token' as defined by RFC
// 1521 and RFC 2045.
func isTokenChar(r rune) bool {
	// token := 1*<any (US-ASCII) CHAR except SPACE, CTLs,
	//             or tspecials>

				first = false
			} else {
				ranges[i].last = r - 1
				i++
				first = true
			}
		}
	}

	return len(ranges)
}

type singleRange struct {
	first rune
	last  rune

	"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.

The [RuneLen] function returns the number of 16-bit words in
the UTF-16 encoding of the rune. It returns -1 if the rune

		}
		// 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
	}

}

// hexDecode decodes a short hex digit sequence: "10" -> 16.
func hexDecode(s []byte) rune {
	n := '\x00'
	for _, c := range s {
		n <<= 4
		switch {
		case '0' <= c && c <= '9':
			n |= rune(c - '0')
		case 'a' <= c && c <= 'f':
			n |= rune(c-'a') + 10
		case 'A' <= c && c <= 'F':
			n |= rune(c-'A') + 10
		default:
			panic(fmt.Sprintf("Bad hex digit in %q", s))
		}
	}
	return n

		sep := ""
		for i := 0; i < len(re.Rune); i += 2 {
			b.WriteString(sep)
			sep = " "
			lo, hi := re.Rune[i], re.Rune[i+1]
			if lo == hi {
				fmt.Fprintf(b, "%#x", lo)
			} else {
				fmt.Fprintf(b, "%#x-%#x", lo, hi)
			}
		}
	}
	b.WriteByte('}')
}

func mkCharClass(f func(rune) bool) string {
	re := &Regexp{Op: OpCharClass}
	lo := rune(-1)
	for i := rune(0); i <= unicode.MaxRune; i++ {

package syntax

import "testing"

var compileTests = []struct {
	Regexp string
	Prog   string
}{
	{"a", `  0	fail
  1*	rune1 "a" -> 2
  2	match
`},
	{"[A-M][n-z]", `  0	fail
  1*	rune "AM" -> 2
  2	rune "nz" -> 3
  3	match
`},
	{"", `  0	fail
  1*	nop -> 2
  2	match
`},
	{"a?", `  0	fail
  1	rune1 "a" -> 3
  2*	alt -> 1, 3
  3	match
`},
	{"a??", `  0	fail
  1	rune1 "a" -> 3

var notletterTest = []rune{
	0x20,
	0x35,
	0x375,
	0x619,
	0x700,
	0x1885,
	0xfffe,
	0x1ffff,
	0x10ffff,
}

// Contains all the special cased Latin-1 chars.
var spaceTest = []rune{
	0x09,
	0x0a,
	0x0b,
	0x0c,
	0x0d,
	0x20,
	0x85,
	0xA0,
	0x2000,
	0x3000,
}

type caseT struct {
	cas     int
	in, out rune
}

var caseTest = []caseT{
	// errors