Add Go frontend, libgo library, and Go testsuite.

gcc/:
	* gcc.c (default_compilers): Add entry for ".go".
	* common.opt: Add -static-libgo as a driver option.
	* doc/install.texi (Configuration): Mention libgo as an option for
	--enable-shared.  Mention go as an option for --enable-languages.
	* doc/invoke.texi (Overall Options): Mention .go as a file name
	suffix.  Mention go as a -x option.
	* doc/frontends.texi (G++ and GCC): Mention Go as a supported
	language.
	* doc/sourcebuild.texi (Top Level): Mention libgo.
	* doc/standards.texi (Standards): Add section on Go language.
	Move references for other languages into their own section.
	* doc/contrib.texi (Contributors): Mention that I contributed the
	Go frontend.
gcc/testsuite/:
	* lib/go.exp: New file.
	* lib/go-dg.exp: New file.
	* lib/go-torture.exp: New file.
	* lib/target-supports.exp (check_compile): Match // Go.

From-SVN: r167407

3 files changed, 2216 insertions, 0 deletions

diff --git a/libgo/go/regexp/all_test.go b/libgo/go/regexp/all_test.go
new file mode 100644
index 0000000..d5a0e7d
--- /dev/null
+++ b/libgo/go/regexp/all_test.go
@@ -0,0 +1,362 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package regexp
+
+import (
+	"os"
+	"strings"
+	"testing"
+)
+
+var good_re = []string{
+	``,
+	`.`,
+	`^.$`,
+	`a`,
+	`a*`,
+	`a+`,
+	`a?`,
+	`a|b`,
+	`a*|b*`,
+	`(a*|b)(c*|d)`,
+	`[a-z]`,
+	`[a-abc-c\-\]\[]`,
+	`[a-z]+`,
+	`[]`,
+	`[abc]`,
+	`[^1234]`,
+	`[^\n]`,
+	`\!\\`,
+}
+
+type stringError struct {
+	re  string
+	err os.Error
+}
+
+var bad_re = []stringError{
+	{`*`, ErrBareClosure},
+	{`(abc`, ErrUnmatchedLpar},
+	{`abc)`, ErrUnmatchedRpar},
+	{`x[a-z`, ErrUnmatchedLbkt},
+	{`abc]`, ErrUnmatchedRbkt},
+	{`[z-a]`, ErrBadRange},
+	{`abc\`, ErrExtraneousBackslash},
+	{`a**`, ErrBadClosure},
+	{`a*+`, ErrBadClosure},
+	{`a??`, ErrBadClosure},
+	{`*`, ErrBareClosure},
+	{`\x`, ErrBadBackslash},
+}
+
+func compileTest(t *testing.T, expr string, error os.Error) *Regexp {
+	re, err := Compile(expr)
+	if err != error {
+		t.Error("compiling `", expr, "`; unexpected error: ", err.String())
+	}
+	return re
+}
+
+func TestGoodCompile(t *testing.T) {
+	for i := 0; i < len(good_re); i++ {
+		compileTest(t, good_re[i], nil)
+	}
+}
+
+func TestBadCompile(t *testing.T) {
+	for i := 0; i < len(bad_re); i++ {
+		compileTest(t, bad_re[i].re, bad_re[i].err)
+	}
+}
+
+func matchTest(t *testing.T, test *FindTest) {
+	re := compileTest(t, test.pat, nil)
+	if re == nil {
+		return
+	}
+	m := re.MatchString(test.text)
+	if m != (len(test.matches) > 0) {
+		t.Errorf("MatchString failure on %s: %t should be %t", test, m, len(test.matches) > 0)
+	}
+	// now try bytes
+	m = re.Match([]byte(test.text))
+	if m != (len(test.matches) > 0) {
+		t.Errorf("Match failure on %s: %t should be %t", test, m, len(test.matches) > 0)
+	}
+}
+
+func TestMatch(t *testing.T) {
+	for _, test := range findTests {
+		matchTest(t, &test)
+	}
+}
+
+func matchFunctionTest(t *testing.T, test *FindTest) {
+	m, err := MatchString(test.pat, test.text)
+	if err == nil {
+		return
+	}
+	if m != (len(test.matches) > 0) {
+		t.Errorf("Match failure on %s: %t should be %t", test, m, len(test.matches) > 0)
+	}
+}
+
+func TestMatchFunction(t *testing.T) {
+	for _, test := range findTests {
+		matchFunctionTest(t, &test)
+	}
+}
+
+type ReplaceTest struct {
+	pattern, replacement, input, output string
+}
+
+var replaceTests = []ReplaceTest{
+	// Test empty input and/or replacement, with pattern that matches the empty string.
+	{"", "", "", ""},
+	{"", "x", "", "x"},
+	{"", "", "abc", "abc"},
+	{"", "x", "abc", "xaxbxcx"},
+
+	// Test empty input and/or replacement, with pattern that does not match the empty string.
+	{"b", "", "", ""},
+	{"b", "x", "", ""},
+	{"b", "", "abc", "ac"},
+	{"b", "x", "abc", "axc"},
+	{"y", "", "", ""},
+	{"y", "x", "", ""},
+	{"y", "", "abc", "abc"},
+	{"y", "x", "abc", "abc"},
+
+	// Multibyte characters -- verify that we don't try to match in the middle
+	// of a character.
+	{"[a-c]*", "x", "\u65e5", "x\u65e5x"},
+	{"[^\u65e5]", "x", "abc\u65e5def", "xxx\u65e5xxx"},
+
+	// Start and end of a string.
+	{"^[a-c]*", "x", "abcdabc", "xdabc"},
+	{"[a-c]*$", "x", "abcdabc", "abcdx"},
+	{"^[a-c]*$", "x", "abcdabc", "abcdabc"},
+	{"^[a-c]*", "x", "abc", "x"},
+	{"[a-c]*$", "x", "abc", "x"},
+	{"^[a-c]*$", "x", "abc", "x"},
+	{"^[a-c]*", "x", "dabce", "xdabce"},
+	{"[a-c]*$", "x", "dabce", "dabcex"},
+	{"^[a-c]*$", "x", "dabce", "dabce"},
+	{"^[a-c]*", "x", "", "x"},
+	{"[a-c]*$", "x", "", "x"},
+	{"^[a-c]*$", "x", "", "x"},
+
+	{"^[a-c]+", "x", "abcdabc", "xdabc"},
+	{"[a-c]+$", "x", "abcdabc", "abcdx"},
+	{"^[a-c]+$", "x", "abcdabc", "abcdabc"},
+	{"^[a-c]+", "x", "abc", "x"},
+	{"[a-c]+$", "x", "abc", "x"},
+	{"^[a-c]+$", "x", "abc", "x"},
+	{"^[a-c]+", "x", "dabce", "dabce"},
+	{"[a-c]+$", "x", "dabce", "dabce"},
+	{"^[a-c]+$", "x", "dabce", "dabce"},
+	{"^[a-c]+", "x", "", ""},
+	{"[a-c]+$", "x", "", ""},
+	{"^[a-c]+$", "x", "", ""},
+
+	// Other cases.
+	{"abc", "def", "abcdefg", "defdefg"},
+	{"bc", "BC", "abcbcdcdedef", "aBCBCdcdedef"},
+	{"abc", "", "abcdabc", "d"},
+	{"x", "xXx", "xxxXxxx", "xXxxXxxXxXxXxxXxxXx"},
+	{"abc", "d", "", ""},
+	{"abc", "d", "abc", "d"},
+	{".+", "x", "abc", "x"},
+	{"[a-c]*", "x", "def", "xdxexfx"},
+	{"[a-c]+", "x", "abcbcdcdedef", "xdxdedef"},
+	{"[a-c]*", "x", "abcbcdcdedef", "xdxdxexdxexfx"},
+}
+
+type ReplaceFuncTest struct {
+	pattern       string
+	replacement   func(string) string
+	input, output string
+}
+
+var replaceFuncTests = []ReplaceFuncTest{
+	{"[a-c]", func(s string) string { return "x" + s + "y" }, "defabcdef", "defxayxbyxcydef"},
+	{"[a-c]+", func(s string) string { return "x" + s + "y" }, "defabcdef", "defxabcydef"},
+	{"[a-c]*", func(s string) string { return "x" + s + "y" }, "defabcdef", "xydxyexyfxabcydxyexyfxy"},
+}
+
+func TestReplaceAll(t *testing.T) {
+	for _, tc := range replaceTests {
+		re, err := Compile(tc.pattern)
+		if err != nil {
+			t.Errorf("Unexpected error compiling %q: %v", tc.pattern, err)
+			continue
+		}
+		actual := re.ReplaceAllString(tc.input, tc.replacement)
+		if actual != tc.output {
+			t.Errorf("%q.Replace(%q,%q) = %q; want %q",
+				tc.pattern, tc.input, tc.replacement, actual, tc.output)
+		}
+		// now try bytes
+		actual = string(re.ReplaceAll([]byte(tc.input), []byte(tc.replacement)))
+		if actual != tc.output {
+			t.Errorf("%q.Replace(%q,%q) = %q; want %q",
+				tc.pattern, tc.input, tc.replacement, actual, tc.output)
+		}
+	}
+}
+
+func TestReplaceAllFunc(t *testing.T) {
+	for _, tc := range replaceFuncTests {
+		re, err := Compile(tc.pattern)
+		if err != nil {
+			t.Errorf("Unexpected error compiling %q: %v", tc.pattern, err)
+			continue
+		}
+		actual := re.ReplaceAllStringFunc(tc.input, tc.replacement)
+		if actual != tc.output {
+			t.Errorf("%q.ReplaceFunc(%q,%q) = %q; want %q",
+				tc.pattern, tc.input, tc.replacement, actual, tc.output)
+		}
+		// now try bytes
+		actual = string(re.ReplaceAllFunc([]byte(tc.input), func(s []byte) []byte { return []byte(tc.replacement(string(s))) }))
+		if actual != tc.output {
+			t.Errorf("%q.ReplaceFunc(%q,%q) = %q; want %q",
+				tc.pattern, tc.input, tc.replacement, actual, tc.output)
+		}
+	}
+}
+
+type QuoteMetaTest struct {
+	pattern, output string
+}
+
+var quoteMetaTests = []QuoteMetaTest{
+	{``, ``},
+	{`foo`, `foo`},
+	{`!@#$%^&*()_+-=[{]}\|,<.>/?~`, `!@#\$%\^&\*\(\)_\+-=\[{\]}\\\|,<\.>/\?~`},
+}
+
+func TestQuoteMeta(t *testing.T) {
+	for _, tc := range quoteMetaTests {
+		// Verify that QuoteMeta returns the expected string.
+		quoted := QuoteMeta(tc.pattern)
+		if quoted != tc.output {
+			t.Errorf("QuoteMeta(`%s`) = `%s`; want `%s`",
+				tc.pattern, quoted, tc.output)
+			continue
+		}
+
+		// Verify that the quoted string is in fact treated as expected
+		// by Compile -- i.e. that it matches the original, unquoted string.
+		if tc.pattern != "" {
+			re, err := Compile(quoted)
+			if err != nil {
+				t.Errorf("Unexpected error compiling QuoteMeta(`%s`): %v", tc.pattern, err)
+				continue
+			}
+			src := "abc" + tc.pattern + "def"
+			repl := "xyz"
+			replaced := re.ReplaceAllString(src, repl)
+			expected := "abcxyzdef"
+			if replaced != expected {
+				t.Errorf("QuoteMeta(`%s`).Replace(`%s`,`%s`) = `%s`; want `%s`",
+					tc.pattern, src, repl, replaced, expected)
+			}
+		}
+	}
+}
+
+type numSubexpCase struct {
+	input    string
+	expected int
+}
+
+var numSubexpCases = []numSubexpCase{
+	{``, 0},
+	{`.*`, 0},
+	{`abba`, 0},
+	{`ab(b)a`, 1},
+	{`ab(.*)a`, 1},
+	{`(.*)ab(.*)a`, 2},
+	{`(.*)(ab)(.*)a`, 3},
+	{`(.*)((a)b)(.*)a`, 4},
+	{`(.*)(\(ab)(.*)a`, 3},
+	{`(.*)(\(a\)b)(.*)a`, 3},
+}
+
+func TestNumSubexp(t *testing.T) {
+	for _, c := range numSubexpCases {
+		re := MustCompile(c.input)
+		n := re.NumSubexp()
+		if n != c.expected {
+			t.Errorf("NumSubexp for %q returned %d, expected %d", c.input, n, c.expected)
+		}
+	}
+}
+
+func BenchmarkLiteral(b *testing.B) {
+	x := strings.Repeat("x", 50)
+	b.StopTimer()
+	re := MustCompile(x)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		if !re.MatchString(x) {
+			println("no match!")
+			break
+		}
+	}
+}
+
+func BenchmarkNotLiteral(b *testing.B) {
+	x := strings.Repeat("x", 49)
+	b.StopTimer()
+	re := MustCompile("^" + x)
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		if !re.MatchString(x) {
+			println("no match!")
+			break
+		}
+	}
+}
+
+func BenchmarkMatchClass(b *testing.B) {
+	b.StopTimer()
+	x := strings.Repeat("xxxx", 20) + "w"
+	re := MustCompile("[abcdw]")
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		if !re.MatchString(x) {
+			println("no match!")
+			break
+		}
+	}
+}
+
+func BenchmarkMatchClass_InRange(b *testing.B) {
+	b.StopTimer()
+	// 'b' is betwen 'a' and 'c', so the charclass
+	// range checking is no help here.
+	x := strings.Repeat("bbbb", 20) + "c"
+	re := MustCompile("[ac]")
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		if !re.MatchString(x) {
+			println("no match!")
+			break
+		}
+	}
+}
+
+func BenchmarkReplaceAll(b *testing.B) {
+	x := "abcdefghijklmnopqrstuvwxyz"
+	b.StopTimer()
+	re := MustCompile("[cjrw]")
+	b.StartTimer()
+	for i := 0; i < b.N; i++ {
+		re.ReplaceAllString(x, "")
+	}
+}
diff --git a/libgo/go/regexp/find_test.go b/libgo/go/regexp/find_test.go
new file mode 100644
index 0000000..07f5586
--- /dev/null
+++ b/libgo/go/regexp/find_test.go
@@ -0,0 +1,454 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package regexp
+
+import (
+	"fmt"
+	"testing"
+)
+
+// For each pattern/text pair, what is the expected output of each function?
+// We can derive the textual results from the indexed results, the non-submatch
+// results from the submatched results, the single results from the 'all' results,
+// and the byte results from the string results. Therefore the table includes
+// only the FindAllStringSubmatchIndex result.
+type FindTest struct {
+	pat     string
+	text    string
+	matches [][]int
+}
+
+func (t FindTest) String() string {
+	return fmt.Sprintf("pat: %#q text: %#q", t.pat, t.text)
+}
+
+var findTests = []FindTest{
+	{``, ``, build(1, 0, 0)},
+	{`^abcdefg`, "abcdefg", build(1, 0, 7)},
+	{`a+`, "baaab", build(1, 1, 4)},
+	{"abcd..", "abcdef", build(1, 0, 6)},
+	{`a`, "a", build(1, 0, 1)},
+	{`x`, "y", nil},
+	{`b`, "abc", build(1, 1, 2)},
+	{`.`, "a", build(1, 0, 1)},
+	{`.*`, "abcdef", build(1, 0, 6)},
+	{`^`, "abcde", build(1, 0, 0)},
+	{`$`, "abcde", build(1, 5, 5)},
+	{`^abcd$`, "abcd", build(1, 0, 4)},
+	{`^bcd'`, "abcdef", nil},
+	{`^abcd$`, "abcde", nil},
+	{`a+`, "baaab", build(1, 1, 4)},
+	{`a*`, "baaab", build(3, 0, 0, 1, 4, 5, 5)},
+	{`[a-z]+`, "abcd", build(1, 0, 4)},
+	{`[^a-z]+`, "ab1234cd", build(1, 2, 6)},
+	{`[a\-\]z]+`, "az]-bcz", build(2, 0, 4, 6, 7)},
+	{`[^\n]+`, "abcd\n", build(1, 0, 4)},
+	{`[日本語]+`, "日本語日本語", build(1, 0, 18)},
+	{`日本語+`, "日本語", build(1, 0, 9)},
+	{`日本語+`, "日本語語語語", build(1, 0, 18)},
+	{`()`, "", build(1, 0, 0, 0, 0)},
+	{`(a)`, "a", build(1, 0, 1, 0, 1)},
+	{`(.)(.)`, "日a", build(1, 0, 4, 0, 3, 3, 4)},
+	{`(.*)`, "", build(1, 0, 0, 0, 0)},
+	{`(.*)`, "abcd", build(1, 0, 4, 0, 4)},
+	{`(..)(..)`, "abcd", build(1, 0, 4, 0, 2, 2, 4)},
+	{`(([^xyz]*)(d))`, "abcd", build(1, 0, 4, 0, 4, 0, 3, 3, 4)},
+	{`((a|b|c)*(d))`, "abcd", build(1, 0, 4, 0, 4, 2, 3, 3, 4)},
+	{`(((a|b|c)*)(d))`, "abcd", build(1, 0, 4, 0, 4, 0, 3, 2, 3, 3, 4)},
+	{`\a\b\f\n\r\t\v`, "\a\b\f\n\r\t\v", build(1, 0, 7)},
+	{`[\a\b\f\n\r\t\v]+`, "\a\b\f\n\r\t\v", build(1, 0, 7)},
+
+	{`a*(|(b))c*`, "aacc", build(1, 0, 4, 2, 2, -1, -1)},
+	{`(.*).*`, "ab", build(1, 0, 2, 0, 2)},
+	{`[.]`, ".", build(1, 0, 1)},
+	{`/$`, "/abc/", build(1, 4, 5)},
+	{`/$`, "/abc", nil},
+
+	// multiple matches
+	{`.`, "abc", build(3, 0, 1, 1, 2, 2, 3)},
+	{`(.)`, "abc", build(3, 0, 1, 0, 1, 1, 2, 1, 2, 2, 3, 2, 3)},
+	{`.(.)`, "abcd", build(2, 0, 2, 1, 2, 2, 4, 3, 4)},
+	{`ab*`, "abbaab", build(3, 0, 3, 3, 4, 4, 6)},
+	{`a(b*)`, "abbaab", build(3, 0, 3, 1, 3, 3, 4, 4, 4, 4, 6, 5, 6)},
+
+	// fixed bugs
+	{`ab$`, "cab", build(1, 1, 3)},
+	{`axxb$`, "axxcb", nil},
+	{`data`, "daXY data", build(1, 5, 9)},
+	{`da(.)a$`, "daXY data", build(1, 5, 9, 7, 8)},
+
+	// can backslash-escape any punctuation
+	{`\!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\@\[\\\]\^\_\{\|\}\~`,
+		`!"#$%&'()*+,-./:;<=>?@[\]^_{|}~`, build(1, 0, 31)},
+	{`[\!\"\#\$\%\&\'\(\)\*\+\,\-\.\/\:\;\<\=\>\?\@\[\\\]\^\_\{\|\}\~]+`,
+		`!"#$%&'()*+,-./:;<=>?@[\]^_{|}~`, build(1, 0, 31)},
+	{"\\`", "`", build(1, 0, 1)},
+	{"[\\`]+", "`", build(1, 0, 1)},
+
+	// long set of matches (longer than startSize)
+	{
+		".",
+		"qwertyuiopasdfghjklzxcvbnm1234567890",
+		build(36, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10,
+			10, 11, 11, 12, 12, 13, 13, 14, 14, 15, 15, 16, 16, 17, 17, 18, 18, 19, 19, 20,
+			20, 21, 21, 22, 22, 23, 23, 24, 24, 25, 25, 26, 26, 27, 27, 28, 28, 29, 29, 30,
+			30, 31, 31, 32, 32, 33, 33, 34, 34, 35, 35, 36),
+	},
+}
+
+// build is a helper to construct a [][]int by extracting n sequences from x.
+// This represents n matches with len(x)/n submatches each.
+func build(n int, x ...int) [][]int {
+	ret := make([][]int, n)
+	runLength := len(x) / n
+	j := 0
+	for i := range ret {
+		ret[i] = make([]int, runLength)
+		copy(ret[i], x[j:])
+		j += runLength
+		if j > len(x) {
+			panic("invalid build entry")
+		}
+	}
+	return ret
+}
+
+// First the simple cases.
+
+func TestFind(t *testing.T) {
+	for _, test := range findTests {
+		result := MustCompile(test.pat).Find([]byte(test.text))
+		switch {
+		case len(test.matches) == 0 && len(result) == 0:
+			// ok
+		case test.matches == nil && result != nil:
+			t.Errorf("expected no match; got one: %s", test)
+		case test.matches != nil && result == nil:
+			t.Errorf("expected match; got none: %s", test)
+		case test.matches != nil && result != nil:
+			expect := test.text[test.matches[0][0]:test.matches[0][1]]
+			if expect != string(result) {
+				t.Errorf("expected %q got %q: %s", expect, result, test)
+			}
+		}
+	}
+}
+
+func TestFindString(t *testing.T) {
+	for _, test := range findTests {
+		result := MustCompile(test.pat).FindString(test.text)
+		switch {
+		case len(test.matches) == 0 && len(result) == 0:
+			// ok
+		case test.matches == nil && result != "":
+			t.Errorf("expected no match; got one: %s", test)
+		case test.matches != nil && result == "":
+			// Tricky because an empty result has two meanings: no match or empty match.
+			if test.matches[0][0] != test.matches[0][1] {
+				t.Errorf("expected match; got none: %s", test)
+			}
+		case test.matches != nil && result != "":
+			expect := test.text[test.matches[0][0]:test.matches[0][1]]
+			if expect != result {
+				t.Errorf("expected %q got %q: %s", expect, result, test)
+			}
+		}
+	}
+}
+
+func testFindIndex(test *FindTest, result []int, t *testing.T) {
+	switch {
+	case len(test.matches) == 0 && len(result) == 0:
+		// ok
+	case test.matches == nil && result != nil:
+		t.Errorf("expected no match; got one: %s", test)
+	case test.matches != nil && result == nil:
+		t.Errorf("expected match; got none: %s", test)
+	case test.matches != nil && result != nil:
+		expect := test.matches[0]
+		if expect[0] != result[0] || expect[1] != result[1] {
+			t.Errorf("expected %v got %v: %s", expect, result, test)
+		}
+	}
+}
+
+func TestFindIndex(t *testing.T) {
+	for _, test := range findTests {
+		testFindIndex(&test, MustCompile(test.pat).FindIndex([]byte(test.text)), t)
+	}
+}
+
+func TestFindStringIndex(t *testing.T) {
+	for _, test := range findTests {
+		testFindIndex(&test, MustCompile(test.pat).FindStringIndex(test.text), t)
+	}
+}
+
+// Now come the simple All cases.
+
+func TestFindAll(t *testing.T) {
+	for _, test := range findTests {
+		result := MustCompile(test.pat).FindAll([]byte(test.text), -1)
+		switch {
+		case test.matches == nil && result == nil:
+			// ok
+		case test.matches == nil && result != nil:
+			t.Errorf("expected no match; got one: %s", test)
+		case test.matches != nil && result == nil:
+			t.Errorf("expected match; got none: %s", test)
+		case test.matches != nil && result != nil:
+			if len(test.matches) != len(result) {
+				t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+				continue
+			}
+			for k, e := range test.matches {
+				expect := test.text[e[0]:e[1]]
+				if expect != string(result[k]) {
+					t.Errorf("match %d: expected %q got %q: %s", k, expect, result[k], test)
+				}
+			}
+		}
+	}
+}
+
+func TestFindAllString(t *testing.T) {
+	for _, test := range findTests {
+		result := MustCompile(test.pat).FindAllString(test.text, -1)
+		switch {
+		case test.matches == nil && result == nil:
+			// ok
+		case test.matches == nil && result != nil:
+			t.Errorf("expected no match; got one: %s", test)
+		case test.matches != nil && result == nil:
+			t.Errorf("expected match; got none: %s", test)
+		case test.matches != nil && result != nil:
+			if len(test.matches) != len(result) {
+				t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+				continue
+			}
+			for k, e := range test.matches {
+				expect := test.text[e[0]:e[1]]
+				if expect != result[k] {
+					t.Errorf("expected %q got %q: %s", expect, result, test)
+				}
+			}
+		}
+	}
+}
+
+func testFindAllIndex(test *FindTest, result [][]int, t *testing.T) {
+	switch {
+	case test.matches == nil && result == nil:
+		// ok
+	case test.matches == nil && result != nil:
+		t.Errorf("expected no match; got one: %s", test)
+	case test.matches != nil && result == nil:
+		t.Errorf("expected match; got none: %s", test)
+	case test.matches != nil && result != nil:
+		if len(test.matches) != len(result) {
+			t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+			return
+		}
+		for k, e := range test.matches {
+			if e[0] != result[k][0] || e[1] != result[k][1] {
+				t.Errorf("match %d: expected %v got %v: %s", k, e, result[k], test)
+			}
+		}
+	}
+}
+
+func TestFindAllIndex(t *testing.T) {
+	for _, test := range findTests {
+		testFindAllIndex(&test, MustCompile(test.pat).FindAllIndex([]byte(test.text), -1), t)
+	}
+}
+
+func TestFindAllStringIndex(t *testing.T) {
+	for _, test := range findTests {
+		testFindAllIndex(&test, MustCompile(test.pat).FindAllStringIndex(test.text, -1), t)
+	}
+}
+
+// Now come the Submatch cases.
+
+func testSubmatchBytes(test *FindTest, n int, submatches []int, result [][]byte, t *testing.T) {
+	if len(submatches) != len(result)*2 {
+		t.Errorf("match %d: expected %d submatches; got %d: %s", n, len(submatches)/2, len(result), test)
+		return
+	}
+	for k := 0; k < len(submatches); k += 2 {
+		if submatches[k] == -1 {
+			if result[k/2] != nil {
+				t.Errorf("match %d: expected nil got %q: %s", n, result, test)
+			}
+			continue
+		}
+		expect := test.text[submatches[k]:submatches[k+1]]
+		if expect != string(result[k/2]) {
+			t.Errorf("match %d: expected %q got %q: %s", n, expect, result, test)
+			return
+		}
+	}
+}
+
+func TestFindSubmatch(t *testing.T) {
+	for _, test := range findTests {
+		result := MustCompile(test.pat).FindSubmatch([]byte(test.text))
+		switch {
+		case test.matches == nil && result == nil:
+			// ok
+		case test.matches == nil && result != nil:
+			t.Errorf("expected no match; got one: %s", test)
+		case test.matches != nil && result == nil:
+			t.Errorf("expected match; got none: %s", test)
+		case test.matches != nil && result != nil:
+			testSubmatchBytes(&test, 0, test.matches[0], result, t)
+		}
+	}
+}
+
+func testSubmatchString(test *FindTest, n int, submatches []int, result []string, t *testing.T) {
+	if len(submatches) != len(result)*2 {
+		t.Errorf("match %d: expected %d submatches; got %d: %s", n, len(submatches)/2, len(result), test)
+		return
+	}
+	for k := 0; k < len(submatches); k += 2 {
+		if submatches[k] == -1 {
+			if result[k/2] != "" {
+				t.Errorf("match %d: expected nil got %q: %s", n, result, test)
+			}
+			continue
+		}
+		expect := test.text[submatches[k]:submatches[k+1]]
+		if expect != result[k/2] {
+			t.Errorf("match %d: expected %q got %q: %s", n, expect, result, test)
+			return
+		}
+	}
+}
+
+func TestFindStringSubmatch(t *testing.T) {
+	for _, test := range findTests {
+		result := MustCompile(test.pat).FindStringSubmatch(test.text)
+		switch {
+		case test.matches == nil && result == nil:
+			// ok
+		case test.matches == nil && result != nil:
+			t.Errorf("expected no match; got one: %s", test)
+		case test.matches != nil && result == nil:
+			t.Errorf("expected match; got none: %s", test)
+		case test.matches != nil && result != nil:
+			testSubmatchString(&test, 0, test.matches[0], result, t)
+		}
+	}
+}
+
+func testSubmatchIndices(test *FindTest, n int, expect, result []int, t *testing.T) {
+	if len(expect) != len(result) {
+		t.Errorf("match %d: expected %d matches; got %d: %s", n, len(expect)/2, len(result)/2, test)
+		return
+	}
+	for k, e := range expect {
+		if e != result[k] {
+			t.Errorf("match %d: submatch error: expected %v got %v: %s", n, expect, result, test)
+		}
+	}
+}
+
+func testFindSubmatchIndex(test *FindTest, result []int, t *testing.T) {
+	switch {
+	case test.matches == nil && result == nil:
+		// ok
+	case test.matches == nil && result != nil:
+		t.Errorf("expected no match; got one: %s", test)
+	case test.matches != nil && result == nil:
+		t.Errorf("expected match; got none: %s", test)
+	case test.matches != nil && result != nil:
+		testSubmatchIndices(test, 0, test.matches[0], result, t)
+	}
+}
+
+func TestFindSubmatchIndex(t *testing.T) {
+	for _, test := range findTests {
+		testFindSubmatchIndex(&test, MustCompile(test.pat).FindSubmatchIndex([]byte(test.text)), t)
+	}
+}
+
+func TestFindStringSubmatchndex(t *testing.T) {
+	for _, test := range findTests {
+		testFindSubmatchIndex(&test, MustCompile(test.pat).FindStringSubmatchIndex(test.text), t)
+	}
+}
+
+// Now come the monster AllSubmatch cases.
+
+func TestFindAllSubmatch(t *testing.T) {
+	for _, test := range findTests {
+		result := MustCompile(test.pat).FindAllSubmatch([]byte(test.text), -1)
+		switch {
+		case test.matches == nil && result == nil:
+			// ok
+		case test.matches == nil && result != nil:
+			t.Errorf("expected no match; got one: %s", test)
+		case test.matches != nil && result == nil:
+			t.Errorf("expected match; got none: %s", test)
+		case len(test.matches) != len(result):
+			t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+		case test.matches != nil && result != nil:
+			for k, match := range test.matches {
+				testSubmatchBytes(&test, k, match, result[k], t)
+			}
+		}
+	}
+}
+
+func TestFindAllStringSubmatch(t *testing.T) {
+	for _, test := range findTests {
+		result := MustCompile(test.pat).FindAllStringSubmatch(test.text, -1)
+		switch {
+		case test.matches == nil && result == nil:
+			// ok
+		case test.matches == nil && result != nil:
+			t.Errorf("expected no match; got one: %s", test)
+		case test.matches != nil && result == nil:
+			t.Errorf("expected match; got none: %s", test)
+		case len(test.matches) != len(result):
+			t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+		case test.matches != nil && result != nil:
+			for k, match := range test.matches {
+				testSubmatchString(&test, k, match, result[k], t)
+			}
+		}
+	}
+}
+
+func testFindAllSubmatchIndex(test *FindTest, result [][]int, t *testing.T) {
+	switch {
+	case test.matches == nil && result == nil:
+		// ok
+	case test.matches == nil && result != nil:
+		t.Errorf("expected no match; got one: %s", test)
+	case test.matches != nil && result == nil:
+		t.Errorf("expected match; got none: %s", test)
+	case len(test.matches) != len(result):
+		t.Errorf("expected %d matches; got %d: %s", len(test.matches), len(result), test)
+	case test.matches != nil && result != nil:
+		for k, match := range test.matches {
+			testSubmatchIndices(test, k, match, result[k], t)
+		}
+	}
+}
+
+func TestFindAllSubmatchIndex(t *testing.T) {
+	for _, test := range findTests {
+		testFindAllSubmatchIndex(&test, MustCompile(test.pat).FindAllSubmatchIndex([]byte(test.text), -1), t)
+	}
+}
+
+func TestFindAllStringSubmatchndex(t *testing.T) {
+	for _, test := range findTests {
+		testFindAllSubmatchIndex(&test, MustCompile(test.pat).FindAllStringSubmatchIndex(test.text, -1), t)
+	}
+}
diff --git a/libgo/go/regexp/regexp.go b/libgo/go/regexp/regexp.go
new file mode 100644
index 0000000..d3f03ad
--- /dev/null
+++ b/libgo/go/regexp/regexp.go
@@ -0,0 +1,1400 @@
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package regexp implements a simple regular expression library.
+//
+// The syntax of the regular expressions accepted is:
+//
+//	regexp:
+//		concatenation { '|' concatenation }
+//	concatenation:
+//		{ closure }
+//	closure:
+//		term [ '*' | '+' | '?' ]
+//	term:
+//		'^'
+//		'$'
+//		'.'
+//		character
+//		'[' [ '^' ] { character-range } ']'
+//		'(' regexp ')'
+//	character-range:
+//		character [ '-' character ]
+//
+// All characters are UTF-8-encoded code points.  Backslashes escape special
+// characters, including inside character classes.  The standard Go character
+// escapes are also recognized: \a \b \f \n \r \t \v.
+//
+// There are 16 methods of Regexp that match a regular expression and identify
+// the matched text.  Their names are matched by this regular expression:
+//
+//	Find(All)?(String)?(Submatch)?(Index)?
+//
+// If 'All' is present, the routine matches successive non-overlapping
+// matches of the entire expression.  Empty matches abutting a preceding
+// match are ignored.  The return value is a slice containing the successive
+// return values of the corresponding non-'All' routine.  These routines take
+// an extra integer argument, n; if n >= 0, the function returns at most n
+// matches/submatches.
+//
+// If 'String' is present, the argument is a string; otherwise it is a slice
+// of bytes; return values are adjusted as appropriate.
+//
+// If 'Submatch' is present, the return value is a slice identifying the
+// successive submatches of the expression.  Submatches are matches of
+// parenthesized subexpressions within the regular expression, numbered from
+// left to right in order of opening parenthesis.  Submatch 0 is the match of
+// the entire expression, submatch 1 the match of the first parenthesized
+// subexpression, and so on.
+//
+// If 'Index' is present, matches and submatches are identified by byte index
+// pairs within the input string: result[2*n:2*n+1] identifies the indexes of
+// the nth submatch.  The pair for n==0 identifies the match of the entire
+// expression.  If 'Index' is not present, the match is identified by the
+// text of the match/submatch.  If an index is negative, it means that
+// subexpression did not match any string in the input.
+//
+// (There are a few other methods that do not match this pattern.)
+//
+package regexp
+
+import (
+	"bytes"
+	"io"
+	"os"
+	"strings"
+	"utf8"
+)
+
+var debug = false
+
+// Error is the local type for a parsing error.
+type Error string
+
+func (e Error) String() string {
+	return string(e)
+}
+
+// Error codes returned by failures to parse an expression.
+var (
+	ErrInternal            = Error("internal error")
+	ErrUnmatchedLpar       = Error("unmatched '('")
+	ErrUnmatchedRpar       = Error("unmatched ')'")
+	ErrUnmatchedLbkt       = Error("unmatched '['")
+	ErrUnmatchedRbkt       = Error("unmatched ']'")
+	ErrBadRange            = Error("bad range in character class")
+	ErrExtraneousBackslash = Error("extraneous backslash")
+	ErrBadClosure          = Error("repeated closure (**, ++, etc.)")
+	ErrBareClosure         = Error("closure applies to nothing")
+	ErrBadBackslash        = Error("illegal backslash escape")
+)
+
+// An instruction executed by the NFA
+type instr interface {
+	kind() int   // the type of this instruction: _CHAR, _ANY, etc.
+	next() instr // the instruction to execute after this one
+	setNext(i instr)
+	index() int
+	setIndex(i int)
+	print()
+}
+
+// Fields and methods common to all instructions
+type common struct {
+	_next  instr
+	_index int
+}
+
+func (c *common) next() instr     { return c._next }
+func (c *common) setNext(i instr) { c._next = i }
+func (c *common) index() int      { return c._index }
+func (c *common) setIndex(i int)  { c._index = i }
+
+// Regexp is the representation of a compiled regular expression.
+// The public interface is entirely through methods.
+type Regexp struct {
+	expr        string // the original expression
+	prefix      string // initial plain text string
+	prefixBytes []byte // initial plain text bytes
+	inst        []instr
+	start       instr // first instruction of machine
+	prefixStart instr // where to start if there is a prefix
+	nbra        int   // number of brackets in expression, for subexpressions
+}
+
+const (
+	_START     = iota // beginning of program
+	_END              // end of program: success
+	_BOT              // '^' beginning of text
+	_EOT              // '$' end of text
+	_CHAR             // 'a' regular character
+	_CHARCLASS        // [a-z] character class
+	_ANY              // '.' any character including newline
+	_NOTNL            // [^\n] special case: any character but newline
+	_BRA              // '(' parenthesized expression
+	_EBRA             // ')'; end of '(' parenthesized expression
+	_ALT              // '|' alternation
+	_NOP              // do nothing; makes it easy to link without patching
+)
+
+// --- START start of program
+type _Start struct {
+	common
+}
+
+func (start *_Start) kind() int { return _START }
+func (start *_Start) print()    { print("start") }
+
+// --- END end of program
+type _End struct {
+	common
+}
+
+func (end *_End) kind() int { return _END }
+func (end *_End) print()    { print("end") }
+
+// --- BOT beginning of text
+type _Bot struct {
+	common
+}
+
+func (bot *_Bot) kind() int { return _BOT }
+func (bot *_Bot) print()    { print("bot") }
+
+// --- EOT end of text
+type _Eot struct {
+	common
+}
+
+func (eot *_Eot) kind() int { return _EOT }
+func (eot *_Eot) print()    { print("eot") }
+
+// --- CHAR a regular character
+type _Char struct {
+	common
+	char int
+}
+
+func (char *_Char) kind() int { return _CHAR }
+func (char *_Char) print()    { print("char ", string(char.char)) }
+
+func newChar(char int) *_Char {
+	c := new(_Char)
+	c.char = char
+	return c
+}
+
+// --- CHARCLASS [a-z]
+
+type _CharClass struct {
+	common
+	negate bool // is character class negated? ([^a-z])
+	// slice of int, stored pairwise: [a-z] is (a,z); x is (x,x):
+	ranges     []int
+	cmin, cmax int
+}
+
+func (cclass *_CharClass) kind() int { return _CHARCLASS }
+
+func (cclass *_CharClass) print() {
+	print("charclass")
+	if cclass.negate {
+		print(" (negated)")
+	}
+	for i := 0; i < len(cclass.ranges); i += 2 {
+		l := cclass.ranges[i]
+		r := cclass.ranges[i+1]
+		if l == r {
+			print(" [", string(l), "]")
+		} else {
+			print(" [", string(l), "-", string(r), "]")
+		}
+	}
+}
+
+func (cclass *_CharClass) addRange(a, b int) {
+	// range is a through b inclusive
+	cclass.ranges = append(cclass.ranges, a, b)
+	if a < cclass.cmin {
+		cclass.cmin = a
+	}
+	if b > cclass.cmax {
+		cclass.cmax = b
+	}
+}
+
+func (cclass *_CharClass) matches(c int) bool {
+	if c < cclass.cmin || c > cclass.cmax {
+		return cclass.negate
+	}
+	ranges := cclass.ranges
+	for i := 0; i < len(ranges); i = i + 2 {
+		if ranges[i] <= c && c <= ranges[i+1] {
+			return !cclass.negate
+		}
+	}
+	return cclass.negate
+}
+
+func newCharClass() *_CharClass {
+	c := new(_CharClass)
+	c.ranges = make([]int, 0, 4)
+	c.cmin = 0x10FFFF + 1 // MaxRune + 1
+	c.cmax = -1
+	return c
+}
+
+// --- ANY any character
+type _Any struct {
+	common
+}
+
+func (any *_Any) kind() int { return _ANY }
+func (any *_Any) print()    { print("any") }
+
+// --- NOTNL any character but newline
+type _NotNl struct {
+	common
+}
+
+func (notnl *_NotNl) kind() int { return _NOTNL }
+func (notnl *_NotNl) print()    { print("notnl") }
+
+// --- BRA parenthesized expression
+type _Bra struct {
+	common
+	n int // subexpression number
+}
+
+func (bra *_Bra) kind() int { return _BRA }
+func (bra *_Bra) print()    { print("bra", bra.n) }
+
+// --- EBRA end of parenthesized expression
+type _Ebra struct {
+	common
+	n int // subexpression number
+}
+
+func (ebra *_Ebra) kind() int { return _EBRA }
+func (ebra *_Ebra) print()    { print("ebra ", ebra.n) }
+
+// --- ALT alternation
+type _Alt struct {
+	common
+	left instr // other branch
+}
+
+func (alt *_Alt) kind() int { return _ALT }
+func (alt *_Alt) print()    { print("alt(", alt.left.index(), ")") }
+
+// --- NOP no operation
+type _Nop struct {
+	common
+}
+
+func (nop *_Nop) kind() int { return _NOP }
+func (nop *_Nop) print()    { print("nop") }
+
+func (re *Regexp) add(i instr) instr {
+	i.setIndex(len(re.inst))
+	re.inst = append(re.inst, i)
+	return i
+}
+
+type parser struct {
+	re    *Regexp
+	nlpar int // number of unclosed lpars
+	pos   int
+	ch    int
+}
+
+func (p *parser) error(err Error) {
+	panic(err)
+}
+
+const endOfFile = -1
+
+func (p *parser) c() int { return p.ch }
+
+func (p *parser) nextc() int {
+	if p.pos >= len(p.re.expr) {
+		p.ch = endOfFile
+	} else {
+		c, w := utf8.DecodeRuneInString(p.re.expr[p.pos:])
+		p.ch = c
+		p.pos += w
+	}
+	return p.ch
+}
+
+func newParser(re *Regexp) *parser {
+	p := new(parser)
+	p.re = re
+	p.nextc() // load p.ch
+	return p
+}
+
+func special(c int) bool {
+	for _, r := range `\.+*?()|[]^$` {
+		if c == r {
+			return true
+		}
+	}
+	return false
+}
+
+func ispunct(c int) bool {
+	for _, r := range "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~" {
+		if c == r {
+			return true
+		}
+	}
+	return false
+}
+
+var escapes = []byte("abfnrtv")
+var escaped = []byte("\a\b\f\n\r\t\v")
+
+func escape(c int) int {
+	for i, b := range escapes {
+		if int(b) == c {
+			return i
+		}
+	}
+	return -1
+}
+
+func (p *parser) charClass() instr {
+	cc := newCharClass()
+	if p.c() == '^' {
+		cc.negate = true
+		p.nextc()
+	}
+	left := -1
+	for {
+		switch c := p.c(); c {
+		case ']', endOfFile:
+			if left >= 0 {
+				p.error(ErrBadRange)
+			}
+			// Is it [^\n]?
+			if cc.negate && len(cc.ranges) == 2 &&
+				cc.ranges[0] == '\n' && cc.ranges[1] == '\n' {
+				nl := new(_NotNl)
+				p.re.add(nl)
+				return nl
+			}
+			// Special common case: "[a]" -> "a"
+			if !cc.negate && len(cc.ranges) == 2 && cc.ranges[0] == cc.ranges[1] {
+				c := newChar(cc.ranges[0])
+				p.re.add(c)
+				return c
+			}
+			p.re.add(cc)
+			return cc
+		case '-': // do this before backslash processing
+			p.error(ErrBadRange)
+		case '\\':
+			c = p.nextc()
+			switch {
+			case c == endOfFile:
+				p.error(ErrExtraneousBackslash)
+			case ispunct(c):
+				// c is as delivered
+			case escape(c) >= 0:
+				c = int(escaped[escape(c)])
+			default:
+				p.error(ErrBadBackslash)
+			}
+			fallthrough
+		default:
+			p.nextc()
+			switch {
+			case left < 0: // first of pair
+				if p.c() == '-' { // range
+					p.nextc()
+					left = c
+				} else { // single char
+					cc.addRange(c, c)
+				}
+			case left <= c: // second of pair
+				cc.addRange(left, c)
+				left = -1
+			default:
+				p.error(ErrBadRange)
+			}
+		}
+	}
+	return nil
+}
+
+func (p *parser) term() (start, end instr) {
+	switch c := p.c(); c {
+	case '|', endOfFile:
+		return nil, nil
+	case '*', '+':
+		p.error(ErrBareClosure)
+	case ')':
+		if p.nlpar == 0 {
+			p.error(ErrUnmatchedRpar)
+		}
+		return nil, nil
+	case ']':
+		p.error(ErrUnmatchedRbkt)
+	case '^':
+		p.nextc()
+		start = p.re.add(new(_Bot))
+		return start, start
+	case '$':
+		p.nextc()
+		start = p.re.add(new(_Eot))
+		return start, start
+	case '.':
+		p.nextc()
+		start = p.re.add(new(_Any))
+		return start, start
+	case '[':
+		p.nextc()
+		start = p.charClass()
+		if p.c() != ']' {
+			p.error(ErrUnmatchedLbkt)
+		}
+		p.nextc()
+		return start, start
+	case '(':
+		p.nextc()
+		p.nlpar++
+		p.re.nbra++ // increment first so first subexpr is \1
+		nbra := p.re.nbra
+		start, end = p.regexp()
+		if p.c() != ')' {
+			p.error(ErrUnmatchedLpar)
+		}
+		p.nlpar--
+		p.nextc()
+		bra := new(_Bra)
+		p.re.add(bra)
+		ebra := new(_Ebra)
+		p.re.add(ebra)
+		bra.n = nbra
+		ebra.n = nbra
+		if start == nil {
+			if end == nil {
+				p.error(ErrInternal)
+				return
+			}
+			start = ebra
+		} else {
+			end.setNext(ebra)
+		}
+		bra.setNext(start)
+		return bra, ebra
+	case '\\':
+		c = p.nextc()
+		switch {
+		case c == endOfFile:
+			p.error(ErrExtraneousBackslash)
+		case ispunct(c):
+			// c is as delivered
+		case escape(c) >= 0:
+			c = int(escaped[escape(c)])
+		default:
+			p.error(ErrBadBackslash)
+		}
+		fallthrough
+	default:
+		p.nextc()
+		start = newChar(c)
+		p.re.add(start)
+		return start, start
+	}
+	panic("unreachable")
+}
+
+func (p *parser) closure() (start, end instr) {
+	start, end = p.term()
+	if start == nil {
+		return
+	}
+	switch p.c() {
+	case '*':
+		// (start,end)*:
+		alt := new(_Alt)
+		p.re.add(alt)
+		end.setNext(alt) // after end, do alt
+		alt.left = start // alternate brach: return to start
+		start = alt      // alt becomes new (start, end)
+		end = alt
+	case '+':
+		// (start,end)+:
+		alt := new(_Alt)
+		p.re.add(alt)
+		end.setNext(alt) // after end, do alt
+		alt.left = start // alternate brach: return to start
+		end = alt        // start is unchanged; end is alt
+	case '?':
+		// (start,end)?:
+		alt := new(_Alt)
+		p.re.add(alt)
+		nop := new(_Nop)
+		p.re.add(nop)
+		alt.left = start // alternate branch is start
+		alt.setNext(nop) // follow on to nop
+		end.setNext(nop) // after end, go to nop
+		start = alt      // start is now alt
+		end = nop        // end is nop pointed to by both branches
+	default:
+		return
+	}
+	switch p.nextc() {
+	case '*', '+', '?':
+		p.error(ErrBadClosure)
+	}
+	return
+}
+
+func (p *parser) concatenation() (start, end instr) {
+	for {
+		nstart, nend := p.closure()
+		switch {
+		case nstart == nil: // end of this concatenation
+			if start == nil { // this is the empty string
+				nop := p.re.add(new(_Nop))
+				return nop, nop
+			}
+			return
+		case start == nil: // this is first element of concatenation
+			start, end = nstart, nend
+		default:
+			end.setNext(nstart)
+			end = nend
+		}
+	}
+	panic("unreachable")
+}
+
+func (p *parser) regexp() (start, end instr) {
+	start, end = p.concatenation()
+	for {
+		switch p.c() {
+		default:
+			return
+		case '|':
+			p.nextc()
+			nstart, nend := p.concatenation()
+			alt := new(_Alt)
+			p.re.add(alt)
+			alt.left = start
+			alt.setNext(nstart)
+			nop := new(_Nop)
+			p.re.add(nop)
+			end.setNext(nop)
+			nend.setNext(nop)
+			start, end = alt, nop
+		}
+	}
+	panic("unreachable")
+}
+
+func unNop(i instr) instr {
+	for i.kind() == _NOP {
+		i = i.next()
+	}
+	return i
+}
+
+func (re *Regexp) eliminateNops() {
+	for _, inst := range re.inst {
+		if inst.kind() == _END {
+			continue
+		}
+		inst.setNext(unNop(inst.next()))
+		if inst.kind() == _ALT {
+			alt := inst.(*_Alt)
+			alt.left = unNop(alt.left)
+		}
+	}
+}
+
+func (re *Regexp) dump() {
+	print("prefix <", re.prefix, ">\n")
+	for _, inst := range re.inst {
+		print(inst.index(), ": ")
+		inst.print()
+		if inst.kind() != _END {
+			print(" -> ", inst.next().index())
+		}
+		print("\n")
+	}
+}
+
+func (re *Regexp) doParse() {
+	p := newParser(re)
+	start := new(_Start)
+	re.add(start)
+	s, e := p.regexp()
+	start.setNext(s)
+	re.start = start
+	e.setNext(re.add(new(_End)))
+
+	if debug {
+		re.dump()
+		println()
+	}
+
+	re.eliminateNops()
+	if debug {
+		re.dump()
+		println()
+	}
+	re.setPrefix()
+	if debug {
+		re.dump()
+		println()
+	}
+}
+
+// Extract regular text from the beginning of the pattern.
+// That text can be used by doExecute to speed up matching.
+func (re *Regexp) setPrefix() {
+	var b []byte
+	var utf = make([]byte, utf8.UTFMax)
+	// First instruction is start; skip that.
+	i := re.inst[0].next().index()
+Loop:
+	for i < len(re.inst) {
+		inst := re.inst[i]
+		// stop if this is not a char
+		if inst.kind() != _CHAR {
+			break
+		}
+		// stop if this char can be followed by a match for an empty string,
+		// which includes closures, ^, and $.
+		switch re.inst[inst.next().index()].kind() {
+		case _BOT, _EOT, _ALT:
+			break Loop
+		}
+		n := utf8.EncodeRune(inst.(*_Char).char, utf)
+		b = bytes.Add(b, utf[0:n])
+		i = inst.next().index()
+	}
+	// point prefixStart instruction to first non-CHAR after prefix
+	re.prefixStart = re.inst[i]
+	re.prefixBytes = b
+	re.prefix = string(b)
+}
+
+// Compile parses a regular expression and returns, if successful, a Regexp
+// object that can be used to match against text.
+func Compile(str string) (regexp *Regexp, error os.Error) {
+	regexp = new(Regexp)
+	// doParse will panic if there is a parse error.
+	defer func() {
+		if e := recover(); e != nil {
+			regexp = nil
+			error = e.(Error) // Will re-panic if error was not an Error, e.g. nil-pointer exception
+		}
+	}()
+	regexp.expr = str
+	regexp.inst = make([]instr, 0, 10)
+	regexp.doParse()
+	return
+}
+
+// MustCompile is like Compile but panics if the expression cannot be parsed.
+// It simplifies safe initialization of global variables holding compiled regular
+// expressions.
+func MustCompile(str string) *Regexp {
+	regexp, error := Compile(str)
+	if error != nil {
+		panic(`regexp: compiling "` + str + `": ` + error.String())
+	}
+	return regexp
+}
+
+// NumSubexp returns the number of parenthesized subexpressions in this Regexp.
+func (re *Regexp) NumSubexp() int { return re.nbra }
+
+// The match arena allows us to reduce the garbage generated by tossing
+// match vectors away as we execute.  Matches are ref counted and returned
+// to a free list when no longer active.  Increases a simple benchmark by 22X.
+type matchArena struct {
+	head *matchVec
+	len  int // length of match vector
+}
+
+type matchVec struct {
+	m    []int // pairs of bracketing submatches. 0th is start,end
+	ref  int
+	next *matchVec
+}
+
+func (a *matchArena) new() *matchVec {
+	if a.head == nil {
+		const N = 10
+		block := make([]matchVec, N)
+		for i := 0; i < N; i++ {
+			b := &block[i]
+			b.next = a.head
+			a.head = b
+		}
+	}
+	m := a.head
+	a.head = m.next
+	m.ref = 0
+	if m.m == nil {
+		m.m = make([]int, a.len)
+	}
+	return m
+}
+
+func (a *matchArena) free(m *matchVec) {
+	m.ref--
+	if m.ref == 0 {
+		m.next = a.head
+		a.head = m
+	}
+}
+
+func (a *matchArena) copy(m *matchVec) *matchVec {
+	m1 := a.new()
+	copy(m1.m, m.m)
+	return m1
+}
+
+func (a *matchArena) noMatch() *matchVec {
+	m := a.new()
+	for i := range m.m {
+		m.m[i] = -1 // no match seen; catches cases like "a(b)?c" on "ac"
+	}
+	m.ref = 1
+	return m
+}
+
+type state struct {
+	inst     instr // next instruction to execute
+	prefixed bool  // this match began with a fixed prefix
+	match    *matchVec
+}
+
+// Append new state to to-do list.  Leftmost-longest wins so avoid
+// adding a state that's already active.  The matchVec will be inc-ref'ed
+// if it is assigned to a state.
+func (a *matchArena) addState(s []state, inst instr, prefixed bool, match *matchVec, pos, end int) []state {
+	switch inst.kind() {
+	case _BOT:
+		if pos == 0 {
+			s = a.addState(s, inst.next(), prefixed, match, pos, end)
+		}
+		return s
+	case _EOT:
+		if pos == end {
+			s = a.addState(s, inst.next(), prefixed, match, pos, end)
+		}
+		return s
+	case _BRA:
+		n := inst.(*_Bra).n
+		match.m[2*n] = pos
+		s = a.addState(s, inst.next(), prefixed, match, pos, end)
+		return s
+	case _EBRA:
+		n := inst.(*_Ebra).n
+		match.m[2*n+1] = pos
+		s = a.addState(s, inst.next(), prefixed, match, pos, end)
+		return s
+	}
+	index := inst.index()
+	l := len(s)
+	// States are inserted in order so it's sufficient to see if we have the same
+	// instruction; no need to see if existing match is earlier (it is).
+	for i := 0; i < l; i++ {
+		if s[i].inst.index() == index {
+			return s
+		}
+	}
+	s = append(s, state{inst, prefixed, match})
+	match.ref++
+	if inst.kind() == _ALT {
+		s = a.addState(s, inst.(*_Alt).left, prefixed, a.copy(match), pos, end)
+		// give other branch a copy of this match vector
+		s = a.addState(s, inst.next(), prefixed, a.copy(match), pos, end)
+	}
+	return s
+}
+
+// Accepts either string or bytes - the logic is identical either way.
+// If bytes == nil, scan str.
+func (re *Regexp) doExecute(str string, bytestr []byte, pos int) []int {
+	var s [2][]state
+	s[0] = make([]state, 0, 10)
+	s[1] = make([]state, 0, 10)
+	in, out := 0, 1
+	var final state
+	found := false
+	end := len(str)
+	if bytestr != nil {
+		end = len(bytestr)
+	}
+	// fast check for initial plain substring
+	prefixed := false // has this iteration begun by skipping a prefix?
+	if re.prefix != "" {
+		var advance int
+		if bytestr == nil {
+			advance = strings.Index(str[pos:], re.prefix)
+		} else {
+			advance = bytes.Index(bytestr[pos:], re.prefixBytes)
+		}
+		if advance == -1 {
+			return nil
+		}
+		pos += advance + len(re.prefix)
+		prefixed = true
+	}
+	arena := &matchArena{nil, 2 * (re.nbra + 1)}
+	for pos <= end {
+		if !found {
+			// prime the pump if we haven't seen a match yet
+			match := arena.noMatch()
+			match.m[0] = pos
+			if prefixed {
+				s[out] = arena.addState(s[out], re.prefixStart, true, match, pos, end)
+				prefixed = false // next iteration should start at beginning of machine.
+			} else {
+				s[out] = arena.addState(s[out], re.start.next(), false, match, pos, end)
+			}
+			arena.free(match) // if addState saved it, ref was incremented
+		}
+		in, out = out, in // old out state is new in state
+		// clear out old state
+		old := s[out]
+		for _, state := range old {
+			arena.free(state.match)
+		}
+		s[out] = old[0:0] // truncate state vector
+		if found && len(s[in]) == 0 {
+			// machine has completed
+			break
+		}
+		charwidth := 1
+		c := endOfFile
+		if pos < end {
+			if bytestr == nil {
+				c, charwidth = utf8.DecodeRuneInString(str[pos:end])
+			} else {
+				c, charwidth = utf8.DecodeRune(bytestr[pos:end])
+			}
+		}
+		pos += charwidth
+		for _, st := range s[in] {
+			switch st.inst.kind() {
+			case _BOT:
+			case _EOT:
+			case _CHAR:
+				if c == st.inst.(*_Char).char {
+					s[out] = arena.addState(s[out], st.inst.next(), st.prefixed, st.match, pos, end)
+				}
+			case _CHARCLASS:
+				if st.inst.(*_CharClass).matches(c) {
+					s[out] = arena.addState(s[out], st.inst.next(), st.prefixed, st.match, pos, end)
+				}
+			case _ANY:
+				if c != endOfFile {
+					s[out] = arena.addState(s[out], st.inst.next(), st.prefixed, st.match, pos, end)
+				}
+			case _NOTNL:
+				if c != endOfFile && c != '\n' {
+					s[out] = arena.addState(s[out], st.inst.next(), st.prefixed, st.match, pos, end)
+				}
+			case _BRA:
+			case _EBRA:
+			case _ALT:
+			case _END:
+				// choose leftmost longest
+				if !found || // first
+					st.match.m[0] < final.match.m[0] || // leftmost
+					(st.match.m[0] == final.match.m[0] && pos-charwidth > final.match.m[1]) { // longest
+					if final.match != nil {
+						arena.free(final.match)
+					}
+					final = st
+					final.match.ref++
+					final.match.m[1] = pos - charwidth
+				}
+				found = true
+			default:
+				st.inst.print()
+				panic("unknown instruction in execute")
+			}
+		}
+	}
+	if final.match == nil {
+		return nil
+	}
+	// if match found, back up start of match by width of prefix.
+	if final.prefixed && len(final.match.m) > 0 {
+		final.match.m[0] -= len(re.prefix)
+	}
+	return final.match.m
+}
+
+// MatchString returns whether the Regexp matches the string s.
+// The return value is a boolean: true for match, false for no match.
+func (re *Regexp) MatchString(s string) bool { return len(re.doExecute(s, nil, 0)) > 0 }
+
+// Match returns whether the Regexp matches the byte slice b.
+// The return value is a boolean: true for match, false for no match.
+func (re *Regexp) Match(b []byte) bool { return len(re.doExecute("", b, 0)) > 0 }
+
+
+// MatchString checks whether a textual regular expression
+// matches a string.  More complicated queries need
+// to use Compile and the full Regexp interface.
+func MatchString(pattern string, s string) (matched bool, error os.Error) {
+	re, err := Compile(pattern)
+	if err != nil {
+		return false, err
+	}
+	return re.MatchString(s), nil
+}
+
+// Match checks whether a textual regular expression
+// matches a byte slice.  More complicated queries need
+// to use Compile and the full Regexp interface.
+func Match(pattern string, b []byte) (matched bool, error os.Error) {
+	re, err := Compile(pattern)
+	if err != nil {
+		return false, err
+	}
+	return re.Match(b), nil
+}
+
+// ReplaceAllString returns a copy of src in which all matches for the Regexp
+// have been replaced by repl.  No support is provided for expressions
+// (e.g. \1 or $1) in the replacement string.
+func (re *Regexp) ReplaceAllString(src, repl string) string {
+	return re.ReplaceAllStringFunc(src, func(string) string { return repl })
+}
+
+// ReplaceAllStringFunc returns a copy of src in which all matches for the
+// Regexp have been replaced by the return value of of function repl (whose
+// first argument is the matched string).  No support is provided for
+// expressions (e.g. \1 or $1) in the replacement string.
+func (re *Regexp) ReplaceAllStringFunc(src string, repl func(string) string) string {
+	lastMatchEnd := 0 // end position of the most recent match
+	searchPos := 0    // position where we next look for a match
+	buf := new(bytes.Buffer)
+	for searchPos <= len(src) {
+		a := re.doExecute(src, nil, searchPos)
+		if len(a) == 0 {
+			break // no more matches
+		}
+
+		// Copy the unmatched characters before this match.
+		io.WriteString(buf, src[lastMatchEnd:a[0]])
+
+		// Now insert a copy of the replacement string, but not for a
+		// match of the empty string immediately after another match.
+		// (Otherwise, we get double replacement for patterns that
+		// match both empty and nonempty strings.)
+		if a[1] > lastMatchEnd || a[0] == 0 {
+			io.WriteString(buf, repl(src[a[0]:a[1]]))
+		}
+		lastMatchEnd = a[1]
+
+		// Advance past this match; always advance at least one character.
+		_, width := utf8.DecodeRuneInString(src[searchPos:])
+		if searchPos+width > a[1] {
+			searchPos += width
+		} else if searchPos+1 > a[1] {
+			// This clause is only needed at the end of the input
+			// string.  In that case, DecodeRuneInString returns width=0.
+			searchPos++
+		} else {
+			searchPos = a[1]
+		}
+	}
+
+	// Copy the unmatched characters after the last match.
+	io.WriteString(buf, src[lastMatchEnd:])
+
+	return buf.String()
+}
+
+// ReplaceAll returns a copy of src in which all matches for the Regexp
+// have been replaced by repl.  No support is provided for expressions
+// (e.g. \1 or $1) in the replacement text.
+func (re *Regexp) ReplaceAll(src, repl []byte) []byte {
+	return re.ReplaceAllFunc(src, func([]byte) []byte { return repl })
+}
+
+// ReplaceAllFunc returns a copy of src in which all matches for the
+// Regexp have been replaced by the return value of of function repl (whose
+// first argument is the matched []byte).  No support is provided for
+// expressions (e.g. \1 or $1) in the replacement string.
+func (re *Regexp) ReplaceAllFunc(src []byte, repl func([]byte) []byte) []byte {
+	lastMatchEnd := 0 // end position of the most recent match
+	searchPos := 0    // position where we next look for a match
+	buf := new(bytes.Buffer)
+	for searchPos <= len(src) {
+		a := re.doExecute("", src, searchPos)
+		if len(a) == 0 {
+			break // no more matches
+		}
+
+		// Copy the unmatched characters before this match.
+		buf.Write(src[lastMatchEnd:a[0]])
+
+		// Now insert a copy of the replacement string, but not for a
+		// match of the empty string immediately after another match.
+		// (Otherwise, we get double replacement for patterns that
+		// match both empty and nonempty strings.)
+		if a[1] > lastMatchEnd || a[0] == 0 {
+			buf.Write(repl(src[a[0]:a[1]]))
+		}
+		lastMatchEnd = a[1]
+
+		// Advance past this match; always advance at least one character.
+		_, width := utf8.DecodeRune(src[searchPos:])
+		if searchPos+width > a[1] {
+			searchPos += width
+		} else if searchPos+1 > a[1] {
+			// This clause is only needed at the end of the input
+			// string.  In that case, DecodeRuneInString returns width=0.
+			searchPos++
+		} else {
+			searchPos = a[1]
+		}
+	}
+
+	// Copy the unmatched characters after the last match.
+	buf.Write(src[lastMatchEnd:])
+
+	return buf.Bytes()
+}
+
+// QuoteMeta returns a string that quotes all regular expression metacharacters
+// inside the argument text; the returned string is a regular expression matching
+// the literal text.  For example, QuoteMeta(`[foo]`) returns `\[foo\]`.
+func QuoteMeta(s string) string {
+	b := make([]byte, 2*len(s))
+
+	// A byte loop is correct because all metacharacters are ASCII.
+	j := 0
+	for i := 0; i < len(s); i++ {
+		if special(int(s[i])) {
+			b[j] = '\\'
+			j++
+		}
+		b[j] = s[i]
+		j++
+	}
+	return string(b[0:j])
+}
+
+// Find matches in slice b if b is non-nil, otherwise find matches in string s.
+func (re *Regexp) allMatches(s string, b []byte, n int, deliver func([]int)) {
+	var end int
+	if b == nil {
+		end = len(s)
+	} else {
+		end = len(b)
+	}
+
+	for pos, i, prevMatchEnd := 0, 0, -1; i < n && pos <= end; {
+		matches := re.doExecute(s, b, pos)
+		if len(matches) == 0 {
+			break
+		}
+
+		accept := true
+		if matches[1] == pos {
+			// We've found an empty match.
+			if matches[0] == prevMatchEnd {
+				// We don't allow an empty match right
+				// after a previous match, so ignore it.
+				accept = false
+			}
+			var width int
+			if b == nil {
+				_, width = utf8.DecodeRuneInString(s[pos:end])
+			} else {
+				_, width = utf8.DecodeRune(b[pos:end])
+			}
+			if width > 0 {
+				pos += width
+			} else {
+				pos = end + 1
+			}
+		} else {
+			pos = matches[1]
+		}
+		prevMatchEnd = matches[1]
+
+		if accept {
+			deliver(matches)
+			i++
+		}
+	}
+}
+
+// Find returns a slice holding the text of the leftmost match in b of the regular expression.
+// A return value of nil indicates no match.
+func (re *Regexp) Find(b []byte) []byte {
+	a := re.doExecute("", b, 0)
+	if a == nil {
+		return nil
+	}
+	return b[a[0]:a[1]]
+}
+
+// FindIndex returns a two-element slice of integers defining the location of
+// the leftmost match in b of the regular expression.  The match itself is at
+// b[loc[0]:loc[1]].
+// A return value of nil indicates no match.
+func (re *Regexp) FindIndex(b []byte) (loc []int) {
+	a := re.doExecute("", b, 0)
+	if a == nil {
+		return nil
+	}
+	return a[0:2]
+}
+
+// FindString returns a string holding the text of the leftmost match in s of the regular
+// expression.  If there is no match, the return value is an empty string,
+// but it will also be empty if the regular expression successfully matches
+// an empty string.  Use FindStringIndex or FindStringSubmatch if it is
+// necessary to distinguish these cases.
+func (re *Regexp) FindString(s string) string {
+	a := re.doExecute(s, nil, 0)
+	if a == nil {
+		return ""
+	}
+	return s[a[0]:a[1]]
+}
+
+// FindStringIndex returns a two-element slice of integers defining the
+// location of the leftmost match in s of the regular expression.  The match
+// itself is at s[loc[0]:loc[1]].
+// A return value of nil indicates no match.
+func (re *Regexp) FindStringIndex(s string) []int {
+	a := re.doExecute(s, nil, 0)
+	if a == nil {
+		return nil
+	}
+	return a[0:2]
+}
+
+// FindSubmatch returns a slice of slices holding the text of the leftmost
+// match of the regular expression in b and the matches, if any, of its
+// subexpressions, as defined by the 'Submatch' descriptions in the package
+// comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindSubmatch(b []byte) [][]byte {
+	a := re.doExecute("", b, 0)
+	if a == nil {
+		return nil
+	}
+	ret := make([][]byte, len(a)/2)
+	for i := range ret {
+		if a[2*i] >= 0 {
+			ret[i] = b[a[2*i]:a[2*i+1]]
+		}
+	}
+	return ret
+}
+
+// FindSubmatchIndex returns a slice holding the index pairs identifying the
+// leftmost match of the regular expression in b and the matches, if any, of
+// its subexpressions, as defined by the 'Submatch' and 'Index' descriptions
+// in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindSubmatchIndex(b []byte) []int {
+	return re.doExecute("", b, 0)
+}
+
+// FindStringSubmatch returns a slice of strings holding the text of the
+// leftmost match of the regular expression in s and the matches, if any, of
+// its subexpressions, as defined by the 'Submatch' description in the
+// package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindStringSubmatch(s string) []string {
+	a := re.doExecute(s, nil, 0)
+	if a == nil {
+		return nil
+	}
+	ret := make([]string, len(a)/2)
+	for i := range ret {
+		if a[2*i] >= 0 {
+			ret[i] = s[a[2*i]:a[2*i+1]]
+		}
+	}
+	return ret
+}
+
+// FindStringSubmatchIndex returns a slice holding the index pairs
+// identifying the leftmost match of the regular expression in s and the
+// matches, if any, of its subexpressions, as defined by the 'Submatch' and
+// 'Index' descriptions in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindStringSubmatchIndex(s string) []int {
+	return re.doExecute(s, nil, 0)
+}
+
+const startSize = 10 // The size at which to start a slice in the 'All' routines.
+
+// FindAll is the 'All' version of Find; it returns a slice of all successive
+// matches of the expression, as defined by the 'All' description in the
+// package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAll(b []byte, n int) [][]byte {
+	if n < 0 {
+		n = len(b) + 1
+	}
+	result := make([][]byte, 0, startSize)
+	re.allMatches("", b, n, func(match []int) {
+		result = append(result, b[match[0]:match[1]])
+	})
+	if len(result) == 0 {
+		return nil
+	}
+	return result
+}
+
+// FindAllIndex is the 'All' version of FindIndex; it returns a slice of all
+// successive matches of the expression, as defined by the 'All' description
+// in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllIndex(b []byte, n int) [][]int {
+	if n < 0 {
+		n = len(b) + 1
+	}
+	result := make([][]int, 0, startSize)
+	re.allMatches("", b, n, func(match []int) {
+		result = append(result, match[0:2])
+	})
+	if len(result) == 0 {
+		return nil
+	}
+	return result
+}
+
+// FindAllString is the 'All' version of FindString; it returns a slice of all
+// successive matches of the expression, as defined by the 'All' description
+// in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllString(s string, n int) []string {
+	if n < 0 {
+		n = len(s) + 1
+	}
+	result := make([]string, 0, startSize)
+	re.allMatches(s, nil, n, func(match []int) {
+		result = append(result, s[match[0]:match[1]])
+	})
+	if len(result) == 0 {
+		return nil
+	}
+	return result
+}
+
+// FindAllStringIndex is the 'All' version of FindStringIndex; it returns a
+// slice of all successive matches of the expression, as defined by the 'All'
+// description in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllStringIndex(s string, n int) [][]int {
+	if n < 0 {
+		n = len(s) + 1
+	}
+	result := make([][]int, 0, startSize)
+	re.allMatches(s, nil, n, func(match []int) {
+		result = append(result, match[0:2])
+	})
+	if len(result) == 0 {
+		return nil
+	}
+	return result
+}
+
+// FindAllSubmatch is the 'All' version of FindSubmatch; it returns a slice
+// of all successive matches of the expression, as defined by the 'All'
+// description in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllSubmatch(b []byte, n int) [][][]byte {
+	if n < 0 {
+		n = len(b) + 1
+	}
+	result := make([][][]byte, 0, startSize)
+	re.allMatches("", b, n, func(match []int) {
+		slice := make([][]byte, len(match)/2)
+		for j := range slice {
+			if match[2*j] >= 0 {
+				slice[j] = b[match[2*j]:match[2*j+1]]
+			}
+		}
+		result = append(result, slice)
+	})
+	if len(result) == 0 {
+		return nil
+	}
+	return result
+}
+
+// FindAllSubmatchIndex is the 'All' version of FindSubmatchIndex; it returns
+// a slice of all successive matches of the expression, as defined by the
+// 'All' description in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllSubmatchIndex(b []byte, n int) [][]int {
+	if n < 0 {
+		n = len(b) + 1
+	}
+	result := make([][]int, 0, startSize)
+	re.allMatches("", b, n, func(match []int) {
+		result = append(result, match)
+	})
+	if len(result) == 0 {
+		return nil
+	}
+	return result
+}
+
+// FindAllStringSubmatch is the 'All' version of FindStringSubmatch; it
+// returns a slice of all successive matches of the expression, as defined by
+// the 'All' description in the package comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllStringSubmatch(s string, n int) [][]string {
+	if n < 0 {
+		n = len(s) + 1
+	}
+	result := make([][]string, 0, startSize)
+	re.allMatches(s, nil, n, func(match []int) {
+		slice := make([]string, len(match)/2)
+		for j := range slice {
+			if match[2*j] >= 0 {
+				slice[j] = s[match[2*j]:match[2*j+1]]
+			}
+		}
+		result = append(result, slice)
+	})
+	if len(result) == 0 {
+		return nil
+	}
+	return result
+}
+
+// FindAllStringSubmatchIndex is the 'All' version of
+// FindStringSubmatchIndex; it returns a slice of all successive matches of
+// the expression, as defined by the 'All' description in the package
+// comment.
+// A return value of nil indicates no match.
+func (re *Regexp) FindAllStringSubmatchIndex(s string, n int) [][]int {
+	if n < 0 {
+		n = len(s) + 1
+	}
+	result := make([][]int, 0, startSize)
+	re.allMatches(s, nil, n, func(match []int) {
+		result = append(result, match)
+	})
+	if len(result) == 0 {
+		return nil
+	}
+	return result
+}