diff --git a/src/pkg/exp/locale/collate/build/trie.go b/src/pkg/exp/locale/collate/build/trie.go
new file mode 100644
index 0000000000..894d29305e
--- /dev/null
+++ b/src/pkg/exp/locale/collate/build/trie.go
@@ -0,0 +1,265 @@
+// Copyright 2012 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.
+
+// The trie in this file is used to associate the first full character
+// in a UTF-8 string to a collation element.
+// All but the last byte in a UTF-8 byte sequence are 
+// used to look up offsets in the index table to be used for the next byte.
+// The last byte is used to index into a table of collation elements.
+// This file contains the code for the generation of the trie.
+
+package build
+
+import (
+	"fmt"
+	"hash/fnv"
+	"io"
+	"log"
+	"reflect"
+)
+
+const blockSize = 64
+
+type trie struct {
+	index  []uint16
+	values []uint32
+}
+
+// trieNode is the intermediate trie structure used for generating a trie.
+type trieNode struct {
+	table [256]*trieNode
+	value int64
+	b     byte
+	leaf  bool
+}
+
+func newNode() *trieNode {
+	return new(trieNode)
+}
+
+func (n *trieNode) isInternal() bool {
+	internal := true
+	for i := 0; i < 256; i++ {
+		if nn := n.table[i]; nn != nil {
+			if !internal && !nn.leaf {
+				log.Fatalf("trie:isInternal: node contains both leaf and non-leaf children (%v)", n)
+			}
+			internal = internal && !nn.leaf
+		}
+	}
+	return internal
+}
+
+func (n *trieNode) insert(r rune, value uint32) {
+	for _, b := range []byte(string(r)) {
+		if n.leaf {
+			log.Fatalf("trie:insert: node (%#v) should not be a leaf", n)
+		}
+		nn := n.table[b]
+		if nn == nil {
+			nn = newNode()
+			nn.b = b
+			n.table[b] = nn
+		}
+		n = nn
+	}
+	n.value = int64(value)
+	n.leaf = true
+}
+
+type nodeIndex struct {
+	lookupBlocks []*trieNode
+	valueBlocks  []*trieNode
+
+	lookupBlockIdx map[uint32]int64
+	valueBlockIdx  map[uint32]int64
+}
+
+func newIndex() *nodeIndex {
+	index := &nodeIndex{}
+	index.lookupBlocks = make([]*trieNode, 0)
+	index.valueBlocks = make([]*trieNode, 0)
+	index.lookupBlockIdx = make(map[uint32]int64)
+	index.valueBlockIdx = make(map[uint32]int64)
+	return index
+}
+
+func computeOffsets(index *nodeIndex, n *trieNode) int64 {
+	if n.leaf {
+		return n.value
+	}
+	hasher := fnv.New32()
+	// We only index continuation bytes.
+	for i := 0; i < blockSize; i++ {
+		v := int64(0)
+		if nn := n.table[0x80+i]; nn != nil {
+			v = computeOffsets(index, nn)
+		}
+		hasher.Write([]byte{byte(v >> 24), byte(v >> 16), byte(v >> 8), byte(v)})
+	}
+	h := hasher.Sum32()
+	if n.isInternal() {
+		v, ok := index.lookupBlockIdx[h]
+		if !ok {
+			v = int64(len(index.lookupBlocks))
+			index.lookupBlocks = append(index.lookupBlocks, n)
+			index.lookupBlockIdx[h] = v
+		}
+		n.value = v
+	} else {
+		v, ok := index.valueBlockIdx[h]
+		if !ok {
+			v = int64(len(index.valueBlocks))
+			index.valueBlocks = append(index.valueBlocks, n)
+			index.valueBlockIdx[h] = v
+		}
+		n.value = v
+	}
+	return n.value
+}
+
+func genValueBlock(t *trie, n *trieNode, offset int) error {
+	for i := 0; i < blockSize; i++ {
+		v := int64(0)
+		if nn := n.table[i+offset]; nn != nil {
+			v = nn.value
+		}
+		if v >= 1<<32 {
+			return fmt.Errorf("value %d at index %d does not fit in uint32", v, len(t.values))
+		}
+		t.values = append(t.values, uint32(v))
+	}
+	return nil
+}
+
+func genLookupBlock(t *trie, n *trieNode, offset int) error {
+	for i := 0; i < blockSize; i++ {
+		v := int64(0)
+		if nn := n.table[i+offset]; nn != nil {
+			v = nn.value
+		}
+		if v >= 1<<16 {
+			return fmt.Errorf("value %d at index %d does not fit in uint16", v, len(t.index))
+		}
+		t.index = append(t.index, uint16(v))
+	}
+	return nil
+}
+
+// generate generates and returns the trie for n.
+func (n *trieNode) generate() (t *trie, err error) {
+	seterr := func(e error) {
+		if err == nil {
+			err = e
+		}
+	}
+	index := newIndex()
+	// Values for 7-bit ASCII are stored in the first of two blocks, followed by a nil block.
+	index.valueBlocks = append(index.valueBlocks, nil, nil, nil)
+	// First byte of multi-byte UTF-8 codepoints are indexed in 4th block.
+	index.lookupBlocks = append(index.lookupBlocks, nil, nil, nil, nil)
+	// Index starter bytes of multi-byte UTF-8.
+	for i := 0xC0; i < 0x100; i++ {
+		if n.table[i] != nil {
+			computeOffsets(index, n.table[i])
+		}
+	}
+	t = &trie{}
+	seterr(genValueBlock(t, n, 0))
+	seterr(genValueBlock(t, n, 64))
+	seterr(genValueBlock(t, newNode(), 0))
+	for i := 3; i < len(index.valueBlocks); i++ {
+		seterr(genValueBlock(t, index.valueBlocks[i], 0x80))
+	}
+	if len(index.valueBlocks) >= 1<<16 {
+		seterr(fmt.Errorf("maximum number of value blocks exceeded (%d > %d)", len(index.valueBlocks), 1<<16))
+		return
+	}
+	seterr(genLookupBlock(t, newNode(), 0))
+	seterr(genLookupBlock(t, newNode(), 0))
+	seterr(genLookupBlock(t, newNode(), 0))
+	seterr(genLookupBlock(t, n, 0xC0))
+	for i := 4; i < len(index.lookupBlocks); i++ {
+		seterr(genLookupBlock(t, index.lookupBlocks[i], 0x80))
+	}
+	return
+}
+
+// print writes a compilable trie to w.  It returns the number of characters
+// printed and the size of the generated structure in bytes.
+func (t *trie) print(w io.Writer, name string) (n, size int, err error) {
+	update3 := func(nn, sz int, e error) {
+		n += nn
+		if err == nil {
+			err = e
+		}
+		size += sz
+	}
+	update2 := func(nn int, e error) { update3(nn, 0, e) }
+
+	update3(t.printArrays(w, name))
+	update2(fmt.Fprintf(w, "var %sTrie = ", name))
+	update3(t.printStruct(w, name))
+	update2(fmt.Fprintln(w))
+	return
+}
+
+func (t *trie) printArrays(w io.Writer, name string) (n, size int, err error) {
+	p := func(f string, a ...interface{}) {
+		nn, e := fmt.Fprintf(w, f, a...)
+		n += nn
+		if err == nil {
+			err = e
+		}
+	}
+	nv := len(t.values)
+	p("// %sValues: %d entries, %d bytes\n", name, nv, nv*4)
+	p("// Block 2 is the null block.\n")
+	p("var %sValues = [%d]uint32 {", name, nv)
+	var printnewline bool
+	for i, v := range t.values {
+		if i%blockSize == 0 {
+			p("\n\t// Block %#x, offset %#x", i/blockSize, i)
+		}
+		if i%4 == 0 {
+			printnewline = true
+		}
+		if v != 0 {
+			if printnewline {
+				p("\n\t")
+				printnewline = false
+			}
+			p("%#04x:%#08x, ", i, v)
+		}
+	}
+	p("\n}\n\n")
+	ni := len(t.index)
+	p("// %sLookup: %d entries, %d bytes\n", name, ni, ni*2)
+	p("// Block 0 is the null block.\n")
+	p("var %sLookup = [%d]uint16 {", name, ni)
+	printnewline = false
+	for i, v := range t.index {
+		if i%blockSize == 0 {
+			p("\n\t// Block %#x, offset %#x", i/blockSize, i)
+		}
+		if i%8 == 0 {
+			printnewline = true
+		}
+		if v != 0 {
+			if printnewline {
+				p("\n\t")
+				printnewline = false
+			}
+			p("%#03x:%#02x, ", i, v)
+		}
+	}
+	p("\n}\n\n")
+	return n, nv*4 + ni*2, err
+}
+
+func (t *trie) printStruct(w io.Writer, name string) (n, sz int, err error) {
+	n, err = fmt.Fprintf(w, "trie{ %sLookup[:], %sValues[:]}", name, name)
+	sz += int(reflect.TypeOf(trie{}).Size())
+	return
+}
diff --git a/src/pkg/exp/locale/collate/build/trie_test.go b/src/pkg/exp/locale/collate/build/trie_test.go
new file mode 100644
index 0000000000..c530bb92f9
--- /dev/null
+++ b/src/pkg/exp/locale/collate/build/trie_test.go
@@ -0,0 +1,103 @@
+// Copyright 2012 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 build
+
+import (
+	"bytes"
+	"testing"
+)
+
+// We take the smallest, largest and an arbitrary value for each 
+// of the UTF-8 sequence lengths.
+var testRunes = []rune{
+	0x01, 0x0C, 0x7F, // 1-byte sequences
+	0x80, 0x100, 0x7FF, // 2-byte sequences
+	0x800, 0x999, 0xFFFF, // 3-byte sequences
+	0x10000, 0x10101, 0x10FFFF, // 4-byte sequences
+	0x200, 0x201, 0x202, 0x210, 0x215, // five entries in one sparse block
+}
+
+func makeTestTrie(t *testing.T) trie {
+	n := newNode()
+	for i, r := range testRunes {
+		n.insert(r, uint32(i))
+	}
+	tr, err := n.generate()
+	if err != nil {
+		t.Errorf(err.Error())
+	}
+	return *tr
+}
+
+func TestGenerateTrie(t *testing.T) {
+	testdata := makeTestTrie(t)
+	buf := &bytes.Buffer{}
+	testdata.print(buf, "test")
+	if output != buf.String() {
+		t.Errorf("output differs")
+	}
+}
+
+var output = `// testValues: 832 entries, 3328 bytes
+// Block 2 is the null block.
+var testValues = [832]uint32 {
+	// Block 0x0, offset 0x0
+	0x000c:0x00000001, 
+	// Block 0x1, offset 0x40
+	0x007f:0x00000002, 
+	// Block 0x2, offset 0x80
+	// Block 0x3, offset 0xc0
+	0x00c0:0x00000003, 
+	// Block 0x4, offset 0x100
+	0x0100:0x00000004, 
+	// Block 0x5, offset 0x140
+	0x0140:0x0000000c, 0x0141:0x0000000d, 0x0142:0x0000000e, 
+	0x0150:0x0000000f, 
+	0x0155:0x00000010, 
+	// Block 0x6, offset 0x180
+	0x01bf:0x00000005, 
+	// Block 0x7, offset 0x1c0
+	0x01c0:0x00000006, 
+	// Block 0x8, offset 0x200
+	0x0219:0x00000007, 
+	// Block 0x9, offset 0x240
+	0x027f:0x00000008, 
+	// Block 0xa, offset 0x280
+	0x0280:0x00000009, 
+	// Block 0xb, offset 0x2c0
+	0x02c1:0x0000000a, 
+	// Block 0xc, offset 0x300
+	0x033f:0x0000000b, 
+}
+
+// testLookup: 640 entries, 1280 bytes
+// Block 0 is the null block.
+var testLookup = [640]uint16 {
+	// Block 0x0, offset 0x0
+	// Block 0x1, offset 0x40
+	// Block 0x2, offset 0x80
+	// Block 0x3, offset 0xc0
+	0x0c2:0x03, 0x0c4:0x04, 
+	0x0c8:0x05, 
+	0x0df:0x06, 
+	0x0e0:0x04, 
+	0x0ef:0x05, 
+	0x0f0:0x07, 0x0f4:0x09, 
+	// Block 0x4, offset 0x100
+	0x120:0x07, 0x126:0x08, 
+	// Block 0x5, offset 0x140
+	0x17f:0x09, 
+	// Block 0x6, offset 0x180
+	0x180:0x0a, 0x184:0x0b, 
+	// Block 0x7, offset 0x1c0
+	0x1d0:0x06, 
+	// Block 0x8, offset 0x200
+	0x23f:0x0c, 
+	// Block 0x9, offset 0x240
+	0x24f:0x08, 
+}
+
+var testTrie = trie{ testLookup[:], testValues[:]}
+`
diff --git a/src/pkg/exp/locale/collate/trie.go b/src/pkg/exp/locale/collate/trie.go
new file mode 100644
index 0000000000..ea0396085d
--- /dev/null
+++ b/src/pkg/exp/locale/collate/trie.go
@@ -0,0 +1,102 @@
+// Copyright 2012 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.
+
+// The trie in this file is used to associate the first full character
+// in an UTF-8 string to a collation element.
+// All but the last byte in a UTF-8 byte sequence are 
+// used to lookup offsets in the index table to be used for the next byte.
+// The last byte is used to index into a table of collation elements.
+// For a full description, see exp/locale/collate/build/trie.go.
+
+package collate
+
+const blockSize = 64
+
+type trie struct {
+	index  []uint16
+	values []uint32
+}
+
+const (
+	t1 = 0x00 // 0000 0000
+	tx = 0x80 // 1000 0000
+	t2 = 0xC0 // 1100 0000
+	t3 = 0xE0 // 1110 0000
+	t4 = 0xF0 // 1111 0000
+	t5 = 0xF8 // 1111 1000
+	t6 = 0xFC // 1111 1100
+	te = 0xFE // 1111 1110
+
+	maskx = 0x3F // 0011 1111
+	mask2 = 0x1F // 0001 1111
+	mask3 = 0x0F // 0000 1111
+	mask4 = 0x07 // 0000 0111
+)
+
+func (t *trie) lookupValue(n uint16, b byte) colElem {
+	return colElem(t.values[int(n)<<6+int(b&maskx)])
+}
+
+// lookup returns the trie value for the first UTF-8 encoding in s and
+// the width in bytes of this encoding. The size will be 0 if s does not
+// hold enough bytes to complete the encoding. len(s) must be greater than 0.
+func (t *trie) lookup(s []byte) (v colElem, sz int) {
+	c0 := s[0]
+	switch {
+	case c0 < tx:
+		return colElem(t.values[c0]), 1
+	case c0 < t2:
+		return 0, 1
+	case c0 < t3:
+		if len(s) < 2 {
+			return 0, 0
+		}
+		i := t.index[c0]
+		c1 := s[1]
+		if c1 < tx || t2 <= c1 {
+			return 0, 1
+		}
+		return t.lookupValue(i, c1), 2
+	case c0 < t4:
+		if len(s) < 3 {
+			return 0, 0
+		}
+		i := t.index[c0]
+		c1 := s[1]
+		if c1 < tx || t2 <= c1 {
+			return 0, 1
+		}
+		o := int(i)<<6 + int(c1)&maskx
+		i = t.index[o]
+		c2 := s[2]
+		if c2 < tx || t2 <= c2 {
+			return 0, 2
+		}
+		return t.lookupValue(i, c2), 3
+	case c0 < t5:
+		if len(s) < 4 {
+			return 0, 0
+		}
+		i := t.index[c0]
+		c1 := s[1]
+		if c1 < tx || t2 <= c1 {
+			return 0, 1
+		}
+		o := int(i)<<6 + int(c1)&maskx
+		i = t.index[o]
+		c2 := s[2]
+		if c2 < tx || t2 <= c2 {
+			return 0, 2
+		}
+		o = int(i)<<6 + int(c2)&maskx
+		i = t.index[o]
+		c3 := s[3]
+		if c3 < tx || t2 <= c3 {
+			return 0, 3
+		}
+		return t.lookupValue(i, c3), 4
+	}
+	// Illegal rune
+	return 0, 1
+}
diff --git a/src/pkg/exp/locale/collate/trie_test.go b/src/pkg/exp/locale/collate/trie_test.go
new file mode 100644
index 0000000000..b5868cad14
--- /dev/null
+++ b/src/pkg/exp/locale/collate/trie_test.go
@@ -0,0 +1,106 @@
+// Copyright 2012 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 collate
+
+import (
+	"testing"
+)
+
+// We take the smallest, largest and an arbitrary value for each 
+// of the UTF-8 sequence lengths.
+var testRunes = []rune{
+	0x01, 0x0C, 0x7F, // 1-byte sequences
+	0x80, 0x100, 0x7FF, // 2-byte sequences
+	0x800, 0x999, 0xFFFF, // 3-byte sequences
+	0x10000, 0x10101, 0x10FFFF, // 4-byte sequences
+	0x200, 0x201, 0x202, 0x210, 0x215, // five entries in one sparse block
+}
+
+// Test cases for illegal runes.
+type trietest struct {
+	size  int
+	bytes []byte
+}
+
+var tests = []trietest{
+	// illegal runes
+	{1, []byte{0x80}},
+	{1, []byte{0xFF}},
+	{1, []byte{t2, tx - 1}},
+	{1, []byte{t2, t2}},
+	{2, []byte{t3, tx, tx - 1}},
+	{2, []byte{t3, tx, t2}},
+	{1, []byte{t3, tx - 1, tx}},
+	{3, []byte{t4, tx, tx, tx - 1}},
+	{3, []byte{t4, tx, tx, t2}},
+	{1, []byte{t4, t2, tx, tx - 1}},
+	{2, []byte{t4, tx, t2, tx - 1}},
+
+	// short runes
+	{0, []byte{t2}},
+	{0, []byte{t3, tx}},
+	{0, []byte{t4, tx, tx}},
+
+	// we only support UTF-8 up to utf8.UTFMax bytes (4 bytes)
+	{1, []byte{t5, tx, tx, tx, tx}},
+	{1, []byte{t6, tx, tx, tx, tx, tx}},
+}
+
+func TestLookupTrie(t *testing.T) {
+	for i, r := range testRunes {
+		b := []byte(string(r))
+		v, sz := testTrie.lookup(b)
+		if int(v) != i {
+			t.Errorf("lookup(%U): found value %#x, expected %#x", r, v, i)
+		}
+		if sz != len(b) {
+			t.Errorf("lookup(%U): found size %d, expected %d", r, sz, len(b))
+		}
+	}
+	for i, tt := range tests {
+		v, sz := testTrie.lookup(tt.bytes)
+		if int(v) != 0 {
+			t.Errorf("lookup of illegal rune, case %d: found value %#x, expected 0", i, v)
+		}
+		if sz != tt.size {
+			t.Errorf("lookup of illegal rune, case %d: found size %d, expected %d", i, sz, tt.size)
+		}
+	}
+}
+
+// test data is taken from exp/collate/locale/build/trie_test.go
+var testValues = [832]uint32{
+	0x000c: 0x00000001,
+	0x007f: 0x00000002,
+	0x00c0: 0x00000003,
+	0x0100: 0x00000004,
+	0x0140: 0x0000000c, 0x0141: 0x0000000d, 0x0142: 0x0000000e,
+	0x0150: 0x0000000f,
+	0x0155: 0x00000010,
+	0x01bf: 0x00000005,
+	0x01c0: 0x00000006,
+	0x0219: 0x00000007,
+	0x027f: 0x00000008,
+	0x0280: 0x00000009,
+	0x02c1: 0x0000000a,
+	0x033f: 0x0000000b,
+}
+
+var testLookup = [640]uint16{
+	0x0c2: 0x03, 0x0c4: 0x04,
+	0x0c8: 0x05,
+	0x0df: 0x06,
+	0x0e0: 0x04,
+	0x0ef: 0x05,
+	0x0f0: 0x07, 0x0f4: 0x09,
+	0x120: 0x07, 0x126: 0x08,
+	0x17f: 0x09,
+	0x180: 0x0a, 0x184: 0x0b,
+	0x1d0: 0x06,
+	0x23f: 0x0c,
+	0x24f: 0x08,
+}
+
+var testTrie = trie{testLookup[:], testValues[:]}