16 files changed, 10065 insertions, 0 deletions

diff --git a/vendor/golang.org/x/text/internal/tag/tag.go b/vendor/golang.org/x/text/internal/tag/tag.go
new file mode 100644
index 000000000..b5d348891
--- /dev/null
+++ b/vendor/golang.org/x/text/internal/tag/tag.go
@@ -0,0 +1,100 @@
+// Copyright 2015 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 tag contains functionality handling tags and related data.
+package tag // import "golang.org/x/text/internal/tag"
+
+import "sort"
+
+// An Index converts tags to a compact numeric value.
+//
+// All elements are of size 4. Tags may be up to 4 bytes long. Excess bytes can
+// be used to store additional information about the tag.
+type Index string
+
+// Elem returns the element data at the given index.
+func (s Index) Elem(x int) string {
+	return string(s[x*4 : x*4+4])
+}
+
+// Index reports the index of the given key or -1 if it could not be found.
+// Only the first len(key) bytes from the start of the 4-byte entries will be
+// considered for the search and the first match in Index will be returned.
+func (s Index) Index(key []byte) int {
+	n := len(key)
+	// search the index of the first entry with an equal or higher value than
+	// key in s.
+	index := sort.Search(len(s)/4, func(i int) bool {
+		return cmp(s[i*4:i*4+n], key) != -1
+	})
+	i := index * 4
+	if cmp(s[i:i+len(key)], key) != 0 {
+		return -1
+	}
+	return index
+}
+
+// Next finds the next occurrence of key after index x, which must have been
+// obtained from a call to Index using the same key. It returns x+1 or -1.
+func (s Index) Next(key []byte, x int) int {
+	if x++; x*4 < len(s) && cmp(s[x*4:x*4+len(key)], key) == 0 {
+		return x
+	}
+	return -1
+}
+
+// cmp returns an integer comparing a and b lexicographically.
+func cmp(a Index, b []byte) int {
+	n := len(a)
+	if len(b) < n {
+		n = len(b)
+	}
+	for i, c := range b[:n] {
+		switch {
+		case a[i] > c:
+			return 1
+		case a[i] < c:
+			return -1
+		}
+	}
+	switch {
+	case len(a) < len(b):
+		return -1
+	case len(a) > len(b):
+		return 1
+	}
+	return 0
+}
+
+// Compare returns an integer comparing a and b lexicographically.
+func Compare(a string, b []byte) int {
+	return cmp(Index(a), b)
+}
+
+// FixCase reformats b to the same pattern of cases as form.
+// If returns false if string b is malformed.
+func FixCase(form string, b []byte) bool {
+	if len(form) != len(b) {
+		return false
+	}
+	for i, c := range b {
+		if form[i] <= 'Z' {
+			if c >= 'a' {
+				c -= 'z' - 'Z'
+			}
+			if c < 'A' || 'Z' < c {
+				return false
+			}
+		} else {
+			if c <= 'Z' {
+				c += 'z' - 'Z'
+			}
+			if c < 'a' || 'z' < c {
+				return false
+			}
+		}
+		b[i] = c
+	}
+	return true
+}
diff --git a/vendor/golang.org/x/text/language/common.go b/vendor/golang.org/x/text/language/common.go
new file mode 100644
index 000000000..9d86e1855
--- /dev/null
+++ b/vendor/golang.org/x/text/language/common.go
@@ -0,0 +1,16 @@
+// Code generated by running "go generate" in golang.org/x/text. DO NOT EDIT.
+
+package language
+
+// This file contains code common to the maketables.go and the package code.
+
+// langAliasType is the type of an alias in langAliasMap.
+type langAliasType int8
+
+const (
+	langDeprecated langAliasType = iota
+	langMacro
+	langLegacy
+
+	langAliasTypeUnknown langAliasType = -1
+)
diff --git a/vendor/golang.org/x/text/language/coverage.go b/vendor/golang.org/x/text/language/coverage.go
new file mode 100644
index 000000000..101fd23c1
--- /dev/null
+++ b/vendor/golang.org/x/text/language/coverage.go
@@ -0,0 +1,197 @@
+// Copyright 2014 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 language
+
+import (
+	"fmt"
+	"sort"
+)
+
+// The Coverage interface is used to define the level of coverage of an
+// internationalization service. Note that not all types are supported by all
+// services. As lists may be generated on the fly, it is recommended that users
+// of a Coverage cache the results.
+type Coverage interface {
+	// Tags returns the list of supported tags.
+	Tags() []Tag
+
+	// BaseLanguages returns the list of supported base languages.
+	BaseLanguages() []Base
+
+	// Scripts returns the list of supported scripts.
+	Scripts() []Script
+
+	// Regions returns the list of supported regions.
+	Regions() []Region
+}
+
+var (
+	// Supported defines a Coverage that lists all supported subtags. Tags
+	// always returns nil.
+	Supported Coverage = allSubtags{}
+)
+
+// TODO:
+// - Support Variants, numbering systems.
+// - CLDR coverage levels.
+// - Set of common tags defined in this package.
+
+type allSubtags struct{}
+
+// Regions returns the list of supported regions. As all regions are in a
+// consecutive range, it simply returns a slice of numbers in increasing order.
+// The "undefined" region is not returned.
+func (s allSubtags) Regions() []Region {
+	reg := make([]Region, numRegions)
+	for i := range reg {
+		reg[i] = Region{regionID(i + 1)}
+	}
+	return reg
+}
+
+// Scripts returns the list of supported scripts. As all scripts are in a
+// consecutive range, it simply returns a slice of numbers in increasing order.
+// The "undefined" script is not returned.
+func (s allSubtags) Scripts() []Script {
+	scr := make([]Script, numScripts)
+	for i := range scr {
+		scr[i] = Script{scriptID(i + 1)}
+	}
+	return scr
+}
+
+// BaseLanguages returns the list of all supported base languages. It generates
+// the list by traversing the internal structures.
+func (s allSubtags) BaseLanguages() []Base {
+	base := make([]Base, 0, numLanguages)
+	for i := 0; i < langNoIndexOffset; i++ {
+		// We included "und" already for the value 0.
+		if i != nonCanonicalUnd {
+			base = append(base, Base{langID(i)})
+		}
+	}
+	i := langNoIndexOffset
+	for _, v := range langNoIndex {
+		for k := 0; k < 8; k++ {
+			if v&1 == 1 {
+				base = append(base, Base{langID(i)})
+			}
+			v >>= 1
+			i++
+		}
+	}
+	return base
+}
+
+// Tags always returns nil.
+func (s allSubtags) Tags() []Tag {
+	return nil
+}
+
+// coverage is used used by NewCoverage which is used as a convenient way for
+// creating Coverage implementations for partially defined data. Very often a
+// package will only need to define a subset of slices. coverage provides a
+// convenient way to do this. Moreover, packages using NewCoverage, instead of
+// their own implementation, will not break if later new slice types are added.
+type coverage struct {
+	tags    func() []Tag
+	bases   func() []Base
+	scripts func() []Script
+	regions func() []Region
+}
+
+func (s *coverage) Tags() []Tag {
+	if s.tags == nil {
+		return nil
+	}
+	return s.tags()
+}
+
+// bases implements sort.Interface and is used to sort base languages.
+type bases []Base
+
+func (b bases) Len() int {
+	return len(b)
+}
+
+func (b bases) Swap(i, j int) {
+	b[i], b[j] = b[j], b[i]
+}
+
+func (b bases) Less(i, j int) bool {
+	return b[i].langID < b[j].langID
+}
+
+// BaseLanguages returns the result from calling s.bases if it is specified or
+// otherwise derives the set of supported base languages from tags.
+func (s *coverage) BaseLanguages() []Base {
+	if s.bases == nil {
+		tags := s.Tags()
+		if len(tags) == 0 {
+			return nil
+		}
+		a := make([]Base, len(tags))
+		for i, t := range tags {
+			a[i] = Base{langID(t.lang)}
+		}
+		sort.Sort(bases(a))
+		k := 0
+		for i := 1; i < len(a); i++ {
+			if a[k] != a[i] {
+				k++
+				a[k] = a[i]
+			}
+		}
+		return a[:k+1]
+	}
+	return s.bases()
+}
+
+func (s *coverage) Scripts() []Script {
+	if s.scripts == nil {
+		return nil
+	}
+	return s.scripts()
+}
+
+func (s *coverage) Regions() []Region {
+	if s.regions == nil {
+		return nil
+	}
+	return s.regions()
+}
+
+// NewCoverage returns a Coverage for the given lists. It is typically used by
+// packages providing internationalization services to define their level of
+// coverage. A list may be of type []T or func() []T, where T is either Tag,
+// Base, Script or Region. The returned Coverage derives the value for Bases
+// from Tags if no func or slice for []Base is specified. For other unspecified
+// types the returned Coverage will return nil for the respective methods.
+func NewCoverage(list ...interface{}) Coverage {
+	s := &coverage{}
+	for _, x := range list {
+		switch v := x.(type) {
+		case func() []Base:
+			s.bases = v
+		case func() []Script:
+			s.scripts = v
+		case func() []Region:
+			s.regions = v
+		case func() []Tag:
+			s.tags = v
+		case []Base:
+			s.bases = func() []Base { return v }
+		case []Script:
+			s.scripts = func() []Script { return v }
+		case []Region:
+			s.regions = func() []Region { return v }
+		case []Tag:
+			s.tags = func() []Tag { return v }
+		default:
+			panic(fmt.Sprintf("language: unsupported set type %T", v))
+		}
+	}
+	return s
+}
diff --git a/vendor/golang.org/x/text/language/doc.go b/vendor/golang.org/x/text/language/doc.go
new file mode 100644
index 000000000..8afecd50e
--- /dev/null
+++ b/vendor/golang.org/x/text/language/doc.go
@@ -0,0 +1,102 @@
+// Copyright 2017 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 language implements BCP 47 language tags and related functionality.
+//
+// The most important function of package language is to match a list of
+// user-preferred languages to a list of supported languages.
+// It alleviates the developer of dealing with the complexity of this process
+// and provides the user with the best experience
+// (see https://blog.golang.org/matchlang).
+//
+//
+// Matching preferred against supported languages
+//
+// A Matcher for an application that supports English, Australian English,
+// Danish, and standard Mandarin can be created as follows:
+//
+//    var matcher = language.NewMatcher([]language.Tag{
+//        language.English,   // The first language is used as fallback.
+//        language.MustParse("en-AU"),
+//        language.Danish,
+//        language.Chinese,
+//    })
+//
+// This list of supported languages is typically implied by the languages for
+// which there exists translations of the user interface.
+//
+// User-preferred languages usually come as a comma-separated list of BCP 47
+// language tags.
+// The MatchString finds best matches for such strings:
+//
+//    handler(w http.ResponseWriter, r *http.Request) {
+//        lang, _ := r.Cookie("lang")
+//        accept := r.Header.Get("Accept-Language")
+//        tag, _ := language.MatchStrings(matcher, lang.String(), accept)
+//
+//        // tag should now be used for the initialization of any
+//        // locale-specific service.
+//    }
+//
+// The Matcher's Match method can be used to match Tags directly.
+//
+// Matchers are aware of the intricacies of equivalence between languages, such
+// as deprecated subtags, legacy tags, macro languages, mutual
+// intelligibility between scripts and languages, and transparently passing
+// BCP 47 user configuration.
+// For instance, it will know that a reader of Bokmål Danish can read Norwegian
+// and will know that Cantonese ("yue") is a good match for "zh-HK".
+//
+//
+// Using match results
+//
+// To guarantee a consistent user experience to the user it is important to
+// use the same language tag for the selection of any locale-specific services.
+// For example, it is utterly confusing to substitute spelled-out numbers
+// or dates in one language in text of another language.
+// More subtly confusing is using the wrong sorting order or casing
+// algorithm for a certain language.
+//
+//    All the packages in x/text that provide locale-specific services
+//    (e.g. collate, cases) should be initialized with the tag that was
+//    obtained at the start of an interaction with the user.
+//
+// Note that Tag that is returned by Match and MatchString may differ from any
+// of the supported languages, as it may contain carried over settings from
+// the user tags.
+// This may be inconvenient when your application has some additional
+// locale-specific data for your supported languages.
+// Match and MatchString both return the index of the matched supported tag
+// to simplify associating such data with the matched tag.
+//
+//
+// Canonicalization
+//
+// If one uses the Matcher to compare languages one does not need to
+// worry about canonicalization.
+//
+// The meaning of a Tag varies per application. The language package
+// therefore delays canonicalization and preserves information as much
+// as possible. The Matcher, however, will always take into account that
+// two different tags may represent the same language.
+//
+// By default, only legacy and deprecated tags are converted into their
+// canonical equivalent. All other information is preserved. This approach makes
+// the confidence scores more accurate and allows matchers to distinguish
+// between variants that are otherwise lost.
+//
+// As a consequence, two tags that should be treated as identical according to
+// BCP 47 or CLDR, like "en-Latn" and "en", will be represented differently. The
+// Matcher handles such distinctions, though, and is aware of the
+// equivalence relations. The CanonType type can be used to alter the
+// canonicalization form.
+//
+// References
+//
+// BCP 47 - Tags for Identifying Languages http://tools.ietf.org/html/bcp47
+//
+package language // import "golang.org/x/text/language"
+
+// TODO: explanation on how to match languages for your own locale-specific
+// service.
diff --git a/vendor/golang.org/x/text/language/gen.go b/vendor/golang.org/x/text/language/gen.go
new file mode 100644
index 000000000..302f1940a
--- /dev/null
+++ b/vendor/golang.org/x/text/language/gen.go
@@ -0,0 +1,1712 @@
+// Copyright 2013 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.
+
+// +build ignore
+
+// Language tag table generator.
+// Data read from the web.
+
+package main
+
+import (
+	"bufio"
+	"flag"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"math"
+	"reflect"
+	"regexp"
+	"sort"
+	"strconv"
+	"strings"
+
+	"golang.org/x/text/internal/gen"
+	"golang.org/x/text/internal/tag"
+	"golang.org/x/text/unicode/cldr"
+)
+
+var (
+	test = flag.Bool("test",
+		false,
+		"test existing tables; can be used to compare web data with package data.")
+	outputFile = flag.String("output",
+		"tables.go",
+		"output file for generated tables")
+)
+
+var comment = []string{
+	`
+lang holds an alphabetically sorted list of ISO-639 language identifiers.
+All entries are 4 bytes. The index of the identifier (divided by 4) is the language tag.
+For 2-byte language identifiers, the two successive bytes have the following meaning:
+    - if the first letter of the 2- and 3-letter ISO codes are the same:
+      the second and third letter of the 3-letter ISO code.
+    - otherwise: a 0 and a by 2 bits right-shifted index into altLangISO3.
+For 3-byte language identifiers the 4th byte is 0.`,
+	`
+langNoIndex is a bit vector of all 3-letter language codes that are not used as an index
+in lookup tables. The language ids for these language codes are derived directly
+from the letters and are not consecutive.`,
+	`
+altLangISO3 holds an alphabetically sorted list of 3-letter language code alternatives
+to 2-letter language codes that cannot be derived using the method described above.
+Each 3-letter code is followed by its 1-byte langID.`,
+	`
+altLangIndex is used to convert indexes in altLangISO3 to langIDs.`,
+	`
+langAliasMap maps langIDs to their suggested replacements.`,
+	`
+script is an alphabetically sorted list of ISO 15924 codes. The index
+of the script in the string, divided by 4, is the internal scriptID.`,
+	`
+isoRegionOffset needs to be added to the index of regionISO to obtain the regionID
+for 2-letter ISO codes. (The first isoRegionOffset regionIDs are reserved for
+the UN.M49 codes used for groups.)`,
+	`
+regionISO holds a list of alphabetically sorted 2-letter ISO region codes.
+Each 2-letter codes is followed by two bytes with the following meaning:
+    - [A-Z}{2}: the first letter of the 2-letter code plus these two 
+                letters form the 3-letter ISO code.
+    - 0, n:     index into altRegionISO3.`,
+	`
+regionTypes defines the status of a region for various standards.`,
+	`
+m49 maps regionIDs to UN.M49 codes. The first isoRegionOffset entries are
+codes indicating collections of regions.`,
+	`
+m49Index gives indexes into fromM49 based on the three most significant bits
+of a 10-bit UN.M49 code. To search an UN.M49 code in fromM49, search in
+   fromM49[m49Index[msb39(code)]:m49Index[msb3(code)+1]]
+for an entry where the first 7 bits match the 7 lsb of the UN.M49 code.
+The region code is stored in the 9 lsb of the indexed value.`,
+	`
+fromM49 contains entries to map UN.M49 codes to regions. See m49Index for details.`,
+	`
+altRegionISO3 holds a list of 3-letter region codes that cannot be
+mapped to 2-letter codes using the default algorithm. This is a short list.`,
+	`
+altRegionIDs holds a list of regionIDs the positions of which match those
+of the 3-letter ISO codes in altRegionISO3.`,
+	`
+variantNumSpecialized is the number of specialized variants in variants.`,
+	`
+suppressScript is an index from langID to the dominant script for that language,
+if it exists.  If a script is given, it should be suppressed from the language tag.`,
+	`
+likelyLang is a lookup table, indexed by langID, for the most likely
+scripts and regions given incomplete information. If more entries exist for a
+given language, region and script are the index and size respectively
+of the list in likelyLangList.`,
+	`
+likelyLangList holds lists info associated with likelyLang.`,
+	`
+likelyRegion is a lookup table, indexed by regionID, for the most likely
+languages and scripts given incomplete information. If more entries exist
+for a given regionID, lang and script are the index and size respectively
+of the list in likelyRegionList.
+TODO: exclude containers and user-definable regions from the list.`,
+	`
+likelyRegionList holds lists info associated with likelyRegion.`,
+	`
+likelyScript is a lookup table, indexed by scriptID, for the most likely
+languages and regions given a script.`,
+	`
+matchLang holds pairs of langIDs of base languages that are typically
+mutually intelligible. Each pair is associated with a confidence and
+whether the intelligibility goes one or both ways.`,
+	`
+matchScript holds pairs of scriptIDs where readers of one script
+can typically also read the other. Each is associated with a confidence.`,
+	`
+nRegionGroups is the number of region groups.`,
+	`
+regionInclusion maps region identifiers to sets of regions in regionInclusionBits,
+where each set holds all groupings that are directly connected in a region
+containment graph.`,
+	`
+regionInclusionBits is an array of bit vectors where every vector represents
+a set of region groupings.  These sets are used to compute the distance
+between two regions for the purpose of language matching.`,
+	`
+regionInclusionNext marks, for each entry in regionInclusionBits, the set of
+all groups that are reachable from the groups set in the respective entry.`,
+}
+
+// TODO: consider changing some of these structures to tries. This can reduce
+// memory, but may increase the need for memory allocations. This could be
+// mitigated if we can piggyback on language tags for common cases.
+
+func failOnError(e error) {
+	if e != nil {
+		log.Panic(e)
+	}
+}
+
+type setType int
+
+const (
+	Indexed setType = 1 + iota // all elements must be of same size
+	Linear
+)
+
+type stringSet struct {
+	s              []string
+	sorted, frozen bool
+
+	// We often need to update values after the creation of an index is completed.
+	// We include a convenience map for keeping track of this.
+	update map[string]string
+	typ    setType // used for checking.
+}
+
+func (ss *stringSet) clone() stringSet {
+	c := *ss
+	c.s = append([]string(nil), c.s...)
+	return c
+}
+
+func (ss *stringSet) setType(t setType) {
+	if ss.typ != t && ss.typ != 0 {
+		log.Panicf("type %d cannot be assigned as it was already %d", t, ss.typ)
+	}
+}
+
+// parse parses a whitespace-separated string and initializes ss with its
+// components.
+func (ss *stringSet) parse(s string) {
+	scan := bufio.NewScanner(strings.NewReader(s))
+	scan.Split(bufio.ScanWords)
+	for scan.Scan() {
+		ss.add(scan.Text())
+	}
+}
+
+func (ss *stringSet) assertChangeable() {
+	if ss.frozen {
+		log.Panic("attempt to modify a frozen stringSet")
+	}
+}
+
+func (ss *stringSet) add(s string) {
+	ss.assertChangeable()
+	ss.s = append(ss.s, s)
+	ss.sorted = ss.frozen
+}
+
+func (ss *stringSet) freeze() {
+	ss.compact()
+	ss.frozen = true
+}
+
+func (ss *stringSet) compact() {
+	if ss.sorted {
+		return
+	}
+	a := ss.s
+	sort.Strings(a)
+	k := 0
+	for i := 1; i < len(a); i++ {
+		if a[k] != a[i] {
+			a[k+1] = a[i]
+			k++
+		}
+	}
+	ss.s = a[:k+1]
+	ss.sorted = ss.frozen
+}
+
+type funcSorter struct {
+	fn func(a, b string) bool
+	sort.StringSlice
+}
+
+func (s funcSorter) Less(i, j int) bool {
+	return s.fn(s.StringSlice[i], s.StringSlice[j])
+}
+
+func (ss *stringSet) sortFunc(f func(a, b string) bool) {
+	ss.compact()
+	sort.Sort(funcSorter{f, sort.StringSlice(ss.s)})
+}
+
+func (ss *stringSet) remove(s string) {
+	ss.assertChangeable()
+	if i, ok := ss.find(s); ok {
+		copy(ss.s[i:], ss.s[i+1:])
+		ss.s = ss.s[:len(ss.s)-1]
+	}
+}
+
+func (ss *stringSet) replace(ol, nu string) {
+	ss.s[ss.index(ol)] = nu
+	ss.sorted = ss.frozen
+}
+
+func (ss *stringSet) index(s string) int {
+	ss.setType(Indexed)
+	i, ok := ss.find(s)
+	if !ok {
+		if i < len(ss.s) {
+			log.Panicf("find: item %q is not in list. Closest match is %q.", s, ss.s[i])
+		}
+		log.Panicf("find: item %q is not in list", s)
+
+	}
+	return i
+}
+
+func (ss *stringSet) find(s string) (int, bool) {
+	ss.compact()
+	i := sort.SearchStrings(ss.s, s)
+	return i, i != len(ss.s) && ss.s[i] == s
+}
+
+func (ss *stringSet) slice() []string {
+	ss.compact()
+	return ss.s
+}
+
+func (ss *stringSet) updateLater(v, key string) {
+	if ss.update == nil {
+		ss.update = map[string]string{}
+	}
+	ss.update[v] = key
+}
+
+// join joins the string and ensures that all entries are of the same length.
+func (ss *stringSet) join() string {
+	ss.setType(Indexed)
+	n := len(ss.s[0])
+	for _, s := range ss.s {
+		if len(s) != n {
+			log.Panicf("join: not all entries are of the same length: %q", s)
+		}
+	}
+	ss.s = append(ss.s, strings.Repeat("\xff", n))
+	return strings.Join(ss.s, "")
+}
+
+// ianaEntry holds information for an entry in the IANA Language Subtag Repository.
+// All types use the same entry.
+// See http://tools.ietf.org/html/bcp47#section-5.1 for a description of the various
+// fields.
+type ianaEntry struct {
+	typ            string
+	description    []string
+	scope          string
+	added          string
+	preferred      string
+	deprecated     string
+	suppressScript string
+	macro          string
+	prefix         []string
+}
+
+type builder struct {
+	w    *gen.CodeWriter
+	hw   io.Writer // MultiWriter for w and w.Hash
+	data *cldr.CLDR
+	supp *cldr.SupplementalData
+
+	// indices
+	locale      stringSet // common locales
+	lang        stringSet // canonical language ids (2 or 3 letter ISO codes) with data
+	langNoIndex stringSet // 3-letter ISO codes with no associated data
+	script      stringSet // 4-letter ISO codes
+	region      stringSet // 2-letter ISO or 3-digit UN M49 codes
+	variant     stringSet // 4-8-alphanumeric variant code.
+
+	// Region codes that are groups with their corresponding group IDs.
+	groups map[int]index
+
+	// langInfo
+	registry map[string]*ianaEntry
+}
+
+type index uint
+
+func newBuilder(w *gen.CodeWriter) *builder {
+	r := gen.OpenCLDRCoreZip()
+	defer r.Close()
+	d := &cldr.Decoder{}
+	data, err := d.DecodeZip(r)
+	failOnError(err)
+	b := builder{
+		w:    w,
+		hw:   io.MultiWriter(w, w.Hash),
+		data: data,
+		supp: data.Supplemental(),
+	}
+	b.parseRegistry()
+	return &b
+}
+
+func (b *builder) parseRegistry() {
+	r := gen.OpenIANAFile("assignments/language-subtag-registry")
+	defer r.Close()
+	b.registry = make(map[string]*ianaEntry)
+
+	scan := bufio.NewScanner(r)
+	scan.Split(bufio.ScanWords)
+	var record *ianaEntry
+	for more := scan.Scan(); more; {
+		key := scan.Text()
+		more = scan.Scan()
+		value := scan.Text()
+		switch key {
+		case "Type:":
+			record = &ianaEntry{typ: value}
+		case "Subtag:", "Tag:":
+			if s := strings.SplitN(value, "..", 2); len(s) > 1 {
+				for a := s[0]; a <= s[1]; a = inc(a) {
+					b.addToRegistry(a, record)
+				}
+			} else {
+				b.addToRegistry(value, record)
+			}
+		case "Suppress-Script:":
+			record.suppressScript = value
+		case "Added:":
+			record.added = value
+		case "Deprecated:":
+			record.deprecated = value
+		case "Macrolanguage:":
+			record.macro = value
+		case "Preferred-Value:":
+			record.preferred = value
+		case "Prefix:":
+			record.prefix = append(record.prefix, value)
+		case "Scope:":
+			record.scope = value
+		case "Description:":
+			buf := []byte(value)
+			for more = scan.Scan(); more; more = scan.Scan() {
+				b := scan.Bytes()
+				if b[0] == '%' || b[len(b)-1] == ':' {
+					break
+				}
+				buf = append(buf, ' ')
+				buf = append(buf, b...)
+			}
+			record.description = append(record.description, string(buf))
+			continue
+		default:
+			continue
+		}
+		more = scan.Scan()
+	}
+	if scan.Err() != nil {
+		log.Panic(scan.Err())
+	}
+}
+
+func (b *builder) addToRegistry(key string, entry *ianaEntry) {
+	if info, ok := b.registry[key]; ok {
+		if info.typ != "language" || entry.typ != "extlang" {
+			log.Fatalf("parseRegistry: tag %q already exists", key)
+		}
+	} else {
+		b.registry[key] = entry
+	}
+}
+
+var commentIndex = make(map[string]string)
+
+func init() {
+	for _, s := range comment {
+		key := strings.TrimSpace(strings.SplitN(s, " ", 2)[0])
+		commentIndex[key] = s
+	}
+}
+
+func (b *builder) comment(name string) {
+	if s := commentIndex[name]; len(s) > 0 {
+		b.w.WriteComment(s)
+	} else {
+		fmt.Fprintln(b.w)
+	}
+}
+
+func (b *builder) pf(f string, x ...interface{}) {
+	fmt.Fprintf(b.hw, f, x...)
+	fmt.Fprint(b.hw, "\n")
+}
+
+func (b *builder) p(x ...interface{}) {
+	fmt.Fprintln(b.hw, x...)
+}
+
+func (b *builder) addSize(s int) {
+	b.w.Size += s
+	b.pf("// Size: %d bytes", s)
+}
+
+func (b *builder) writeConst(name string, x interface{}) {
+	b.comment(name)
+	b.w.WriteConst(name, x)
+}
+
+// writeConsts computes f(v) for all v in values and writes the results
+// as constants named _v to a single constant block.
+func (b *builder) writeConsts(f func(string) int, values ...string) {
+	b.pf("const (")
+	for _, v := range values {
+		b.pf("\t_%s = %v", v, f(v))
+	}
+	b.pf(")")
+}
+
+// writeType writes the type of the given value, which must be a struct.
+func (b *builder) writeType(value interface{}) {
+	b.comment(reflect.TypeOf(value).Name())
+	b.w.WriteType(value)
+}
+
+func (b *builder) writeSlice(name string, ss interface{}) {
+	b.writeSliceAddSize(name, 0, ss)
+}
+
+func (b *builder) writeSliceAddSize(name string, extraSize int, ss interface{}) {
+	b.comment(name)
+	b.w.Size += extraSize
+	v := reflect.ValueOf(ss)
+	t := v.Type().Elem()
+	b.pf("// Size: %d bytes, %d elements", v.Len()*int(t.Size())+extraSize, v.Len())
+
+	fmt.Fprintf(b.w, "var %s = ", name)
+	b.w.WriteArray(ss)
+	b.p()
+}
+
+type fromTo s