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Diffstat (limited to 'vendor/golang.org/x/text/language/language.go')
| -rw-r--r-- | vendor/golang.org/x/text/language/language.go | 605 |
1 files changed, 605 insertions, 0 deletions
diff --git a/vendor/golang.org/x/text/language/language.go b/vendor/golang.org/x/text/language/language.go new file mode 100644 index 0000000..4d9c661 --- /dev/null +++ b/vendor/golang.org/x/text/language/language.go @@ -0,0 +1,605 @@ +// 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. + +//go:generate go run gen.go -output tables.go + +package language + +// TODO: Remove above NOTE after: +// - verifying that tables are dropped correctly (most notably matcher tables). + +import ( + "strings" + + "golang.org/x/text/internal/language" + "golang.org/x/text/internal/language/compact" +) + +// Tag represents a BCP 47 language tag. It is used to specify an instance of a +// specific language or locale. All language tag values are guaranteed to be +// well-formed. +type Tag compact.Tag + +func makeTag(t language.Tag) (tag Tag) { + return Tag(compact.Make(t)) +} + +func (t *Tag) tag() language.Tag { + return (*compact.Tag)(t).Tag() +} + +func (t *Tag) isCompact() bool { + return (*compact.Tag)(t).IsCompact() +} + +// TODO: improve performance. +func (t *Tag) lang() language.Language { return t.tag().LangID } +func (t *Tag) region() language.Region { return t.tag().RegionID } +func (t *Tag) script() language.Script { return t.tag().ScriptID } + +// Make is a convenience wrapper for Parse that omits the error. +// In case of an error, a sensible default is returned. +func Make(s string) Tag { + return Default.Make(s) +} + +// Make is a convenience wrapper for c.Parse that omits the error. +// In case of an error, a sensible default is returned. +func (c CanonType) Make(s string) Tag { + t, _ := c.Parse(s) + return t +} + +// Raw returns the raw base language, script and region, without making an +// attempt to infer their values. +func (t Tag) Raw() (b Base, s Script, r Region) { + tt := t.tag() + return Base{tt.LangID}, Script{tt.ScriptID}, Region{tt.RegionID} +} + +// IsRoot returns true if t is equal to language "und". +func (t Tag) IsRoot() bool { + return compact.Tag(t).IsRoot() +} + +// CanonType can be used to enable or disable various types of canonicalization. +type CanonType int + +const ( + // Replace deprecated base languages with their preferred replacements. + DeprecatedBase CanonType = 1 << iota + // Replace deprecated scripts with their preferred replacements. + DeprecatedScript + // Replace deprecated regions with their preferred replacements. + DeprecatedRegion + // Remove redundant scripts. + SuppressScript + // Normalize legacy encodings. This includes legacy languages defined in + // CLDR as well as bibliographic codes defined in ISO-639. + Legacy + // Map the dominant language of a macro language group to the macro language + // subtag. For example cmn -> zh. + Macro + // The CLDR flag should be used if full compatibility with CLDR is required. + // There are a few cases where language.Tag may differ from CLDR. To follow all + // of CLDR's suggestions, use All|CLDR. + CLDR + + // Raw can be used to Compose or Parse without Canonicalization. + Raw CanonType = 0 + + // Replace all deprecated tags with their preferred replacements. + Deprecated = DeprecatedBase | DeprecatedScript | DeprecatedRegion + + // All canonicalizations recommended by BCP 47. + BCP47 = Deprecated | SuppressScript + + // All canonicalizations. + All = BCP47 | Legacy | Macro + + // Default is the canonicalization used by Parse, Make and Compose. To + // preserve as much information as possible, canonicalizations that remove + // potentially valuable information are not included. The Matcher is + // designed to recognize similar tags that would be the same if + // they were canonicalized using All. + Default = Deprecated | Legacy + + canonLang = DeprecatedBase | Legacy | Macro + + // TODO: LikelyScript, LikelyRegion: suppress similar to ICU. +) + +// canonicalize returns the canonicalized equivalent of the tag and +// whether there was any change. +func canonicalize(c CanonType, t language.Tag) (language.Tag, bool) { + if c == Raw { + return t, false + } + changed := false + if c&SuppressScript != 0 { + if t.LangID.SuppressScript() == t.ScriptID { + t.ScriptID = 0 + changed = true + } + } + if c&canonLang != 0 { + for { + if l, aliasType := t.LangID.Canonicalize(); l != t.LangID { + switch aliasType { + case language.Legacy: + if c&Legacy != 0 { + if t.LangID == _sh && t.ScriptID == 0 { + t.ScriptID = _Latn + } + t.LangID = l + changed = true + } + case language.Macro: + if c&Macro != 0 { + // We deviate here from CLDR. The mapping "nb" -> "no" + // qualifies as a typical Macro language mapping. However, + // for legacy reasons, CLDR maps "no", the macro language + // code for Norwegian, to the dominant variant "nb". This + // change is currently under consideration for CLDR as well. + // See https://unicode.org/cldr/trac/ticket/2698 and also + // https://unicode.org/cldr/trac/ticket/1790 for some of the + // practical implications. TODO: this check could be removed + // if CLDR adopts this change. + if c&CLDR == 0 || t.LangID != _nb { + changed = true + t.LangID = l + } + } + case language.Deprecated: + if c&DeprecatedBase != 0 { + if t.LangID == _mo && t.RegionID == 0 { + t.RegionID = _MD + } + t.LangID = l + changed = true + // Other canonicalization types may still apply. + continue + } + } + } else if c&Legacy != 0 && t.LangID == _no && c&CLDR != 0 { + t.LangID = _nb + changed = true + } + break + } + } + if c&DeprecatedScript != 0 { + if t.ScriptID == _Qaai { + changed = true + t.ScriptID = _Zinh + } + } + if c&DeprecatedRegion != 0 { + if r := t.RegionID.Canonicalize(); r != t.RegionID { + changed = true + t.RegionID = r + } + } + return t, changed +} + +// Canonicalize returns the canonicalized equivalent of the tag. +func (c CanonType) Canonicalize(t Tag) (Tag, error) { + // First try fast path. + if t.isCompact() { + if _, changed := canonicalize(c, compact.Tag(t).Tag()); !changed { + return t, nil + } + } + // It is unlikely that one will canonicalize a tag after matching. So do + // a slow but simple approach here. + if tag, changed := canonicalize(c, t.tag()); changed { + tag.RemakeString() + return makeTag(tag), nil + } + return t, nil + +} + +// Confidence indicates the level of certainty for a given return value. +// For example, Serbian may be written in Cyrillic or Latin script. +// The confidence level indicates whether a value was explicitly specified, +// whether it is typically the only possible value, or whether there is +// an ambiguity. +type Confidence int + +const ( + No Confidence = iota // full confidence that there was no match + Low // most likely value picked out of a set of alternatives + High // value is generally assumed to be the correct match + Exact // exact match or explicitly specified value +) + +var confName = []string{"No", "Low", "High", "Exact"} + +func (c Confidence) String() string { + return confName[c] +} + +// String returns the canonical string representation of the language tag. +func (t Tag) String() string { + return t.tag().String() +} + +// MarshalText implements encoding.TextMarshaler. +func (t Tag) MarshalText() (text []byte, err error) { + return t.tag().MarshalText() +} + +// UnmarshalText implements encoding.TextUnmarshaler. +func (t *Tag) UnmarshalText(text []byte) error { + var tag language.Tag + err := tag.UnmarshalText(text) + *t = makeTag(tag) + return err +} + +// Base returns the base language of the language tag. If the base language is +// unspecified, an attempt will be made to infer it from the context. +// It uses a variant of CLDR's Add Likely Subtags algorithm. This is subject to change. +func (t Tag) Base() (Base, Confidence) { + if b := t.lang(); b != 0 { + return Base{b}, Exact + } + tt := t.tag() + c := High + if tt.ScriptID == 0 && !tt.RegionID.IsCountry() { + c = Low + } + if tag, err := tt.Maximize(); err == nil && tag.LangID != 0 { + return Base{tag.LangID}, c + } + return Base{0}, No +} + +// Script infers the script for the language tag. If it was not explicitly given, it will infer +// a most likely candidate. +// If more than one script is commonly used for a language, the most likely one +// is returned with a low confidence indication. For example, it returns (Cyrl, Low) +// for Serbian. +// If a script cannot be inferred (Zzzz, No) is returned. We do not use Zyyy (undetermined) +// as one would suspect from the IANA registry for BCP 47. In a Unicode context Zyyy marks +// common characters (like 1, 2, 3, '.', etc.) and is therefore more like multiple scripts. +// See https://www.unicode.org/reports/tr24/#Values for more details. Zzzz is also used for +// unknown value in CLDR. (Zzzz, Exact) is returned if Zzzz was explicitly specified. +// Note that an inferred script is never guaranteed to be the correct one. Latin is +// almost exclusively used for Afrikaans, but Arabic has been used for some texts +// in the past. Also, the script that is commonly used may change over time. +// It uses a variant of CLDR's Add Likely Subtags algorithm. This is subject to change. +func (t Tag) Script() (Script, Confidence) { + if scr := t.script(); scr != 0 { + return Script{scr}, Exact + } + tt := t.tag() + sc, c := language.Script(_Zzzz), No + if scr := tt.LangID.SuppressScript(); scr != 0 { + // Note: it is not always the case that a language with a suppress + // script value is only written in one script (e.g. kk, ms, pa). + if tt.RegionID == 0 { + return Script{scr}, High + } + sc, c = scr, High + } + if tag, err := tt.Maximize(); err == nil { + if tag.ScriptID != sc { + sc, c = tag.ScriptID, Low + } + } else { + tt, _ = canonicalize(Deprecated|Macro, tt) + if tag, err := tt.Maximize(); err == nil && tag.ScriptID != sc { + sc, c = tag.ScriptID, Low + } + } + return Script{sc}, c +} + +// Region returns the region for the language tag. If it was not explicitly given, it will +// infer a most likely candidate from the context. +// It uses a variant of CLDR's Add Likely Subtags algorithm. This is subject to change. +func (t Tag) Region() (Region, Confidence) { + if r := t.region(); r != 0 { + return Region{r}, Exact + } + tt := t.tag() + if tt, err := tt.Maximize(); err == nil { + return Region{tt.RegionID}, Low // TODO: differentiate between high and low. + } + tt, _ = canonicalize(Deprecated|Macro, tt) + if tag, err := tt.Maximize(); err == nil { + return Region{tag.RegionID}, Low + } + return Region{_ZZ}, No // TODO: return world instead of undetermined? +} + +// Variants returns the variants specified explicitly for this language tag. +// or nil if no variant was specified. +func (t Tag) Variants() []Variant { + if !compact.Tag(t).MayHaveVariants() { + return nil + } + v := []Variant{} + x, str := "", t.tag().Variants() + for str != "" { + x, str = nextToken(str) + v = append(v, Variant{x}) + } + return v +} + +// Parent returns the CLDR parent of t. In CLDR, missing fields in data for a +// specific language are substituted with fields from the parent language. +// The parent for a language may change for newer versions of CLDR. +// +// Parent returns a tag for a less specific language that is mutually +// intelligible or Und if there is no such language. This may not be the same as +// simply stripping the last BCP 47 subtag. For instance, the parent of "zh-TW" +// is "zh-Hant", and the parent of "zh-Hant" is "und". +func (t Tag) Parent() Tag { + return Tag(compact.Tag(t).Parent()) +} + +// nextToken returns token t and the rest of the string. +func nextToken(s string) (t, tail string) { + p := strings.Index(s[1:], "-") + if p == -1 { + return s[1:], "" + } + p++ + return s[1:p], s[p:] +} + +// Extension is a single BCP 47 extension. +type Extension struct { + s string +} + +// String returns the string representation of the extension, including the +// type tag. +func (e Extension) String() string { + return e.s +} + +// ParseExtension parses s as an extension and returns it on success. +func ParseExtension(s string) (e Extension, err error) { + ext, err := language.ParseExtension(s) + return Extension{ext}, err +} + +// Type returns the one-byte extension type of e. It returns 0 for the zero +// exception. +func (e Extension) Type() byte { + if e.s == "" { + return 0 + } + return e.s[0] +} + +// Tokens returns the list of tokens of e. +func (e Extension) Tokens() []string { + return strings.Split(e.s, "-") +} + +// Extension returns the extension of type x for tag t. It will return +// false for ok if t does not have the requested extension. The returned +// extension will be invalid in this case. +func (t Tag) Extension(x byte) (ext Extension, ok bool) { + if !compact.Tag(t).MayHaveExtensions() { + return Extension{}, false + } + e, ok := t.tag().Extension(x) + return Extension{e}, ok +} + +// Extensions returns all extensions of t. +func (t Tag) Extensions() []Extension { + if !compact.Tag(t).MayHaveExtensions() { + return nil + } + e := []Extension{} + for _, ext := range t.tag().Extensions() { + e = append(e, Extension{ext}) + } + return e +} + +// TypeForKey returns the type associated with the given key, where key and type +// are of the allowed values defined for the Unicode locale extension ('u') in +// https://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers. +// TypeForKey will traverse the inheritance chain to get the correct value. +// +// If there are multiple types associated with a key, only the first will be +// returned. If there is no type associated with a key, it returns the empty +// string. +func (t Tag) TypeForKey(key string) string { + if !compact.Tag(t).MayHaveExtensions() { + if key != "rg" && key != "va" { + return "" + } + } + return t.tag().TypeForKey(key) +} + +// SetTypeForKey returns a new Tag with the key set to type, where key and type +// are of the allowed values defined for the Unicode locale extension ('u') in +// https://www.unicode.org/reports/tr35/#Unicode_Language_and_Locale_Identifiers. +// An empty value removes an existing pair with the same key. +func (t Tag) SetTypeForKey(key, value string) (Tag, error) { + tt, err := t.tag().SetTypeForKey(key, value) + return makeTag(tt), err +} + +// NumCompactTags is the number of compact tags. The maximum tag is +// NumCompactTags-1. +const NumCompactTags = compact.NumCompactTags + +// CompactIndex returns an index, where 0 <= index < NumCompactTags, for tags +// for which data exists in the text repository.The index will change over time +// and should not be stored in persistent storage. If t does not match a compact +// index, exact will be false and the compact index will be returned for the +// first match after repeatedly taking the Parent of t. +func CompactIndex(t Tag) (index int, exact bool) { + id, exact := compact.LanguageID(compact.Tag(t)) + return int(id), exact +} + +var root = language.Tag{} + +// Base is an ISO 639 language code, used for encoding the base language +// of a language tag. +type Base struct { + langID language.Language +} + +// ParseBase parses a 2- or 3-letter ISO 639 code. +// It returns a ValueError if s is a well-formed but unknown language identifier +// or another error if another error occurred. +func ParseBase(s string) (Base, error) { + l, err := language.ParseBase(s) + return Base{l}, err +} + +// String returns the BCP 47 representation of the base language. +func (b Base) String() string { + return b.langID.String() +} + +// ISO3 returns the ISO 639-3 language code. +func (b Base) ISO3() string { + return b.langID.ISO3() +} + +// IsPrivateUse reports whether this language code is reserved for private use. +func (b Base) IsPrivateUse() bool { + return b.langID.IsPrivateUse() +} + +// Script is a 4-letter ISO 15924 code for representing scripts. +// It is idiomatically represented in title case. +type Script struct { + scriptID language.Script +} + +// ParseScript parses a 4-letter ISO 15924 code. +// It returns a ValueError if s is a well-formed but unknown script identifier +// or another error if another error occurred. +func ParseScript(s string) (Script, error) { + sc, err := language.ParseScript(s) + return Script{sc}, err +} + +// String returns the script code in title case. +// It returns "Zzzz" for an unspecified script. +func (s Script) String() string { + return s.scriptID.String() +} + +// IsPrivateUse reports whether this script code is reserved for private use. +func (s Script) IsPrivateUse() bool { + return s.scriptID.IsPrivateUse() +} + +// Region is an ISO 3166-1 or UN M.49 code for representing countries and regions. +type Region struct { + regionID language.Region +} + +// EncodeM49 returns the Region for the given UN M.49 code. +// It returns an error if r is not a valid code. +func EncodeM49(r int) (Region, error) { + rid, err := language.EncodeM49(r) + return Region{rid}, err +} + +// ParseRegion parses a 2- or 3-letter ISO 3166-1 or a UN M.49 code. +// It returns a ValueError if s is a well-formed but unknown region identifier +// or another error if another error occurred. +func ParseRegion(s string) (Region, error) { + r, err := language.ParseRegion(s) + return Region{r}, err +} + +// String returns the BCP 47 representation for the region. +// It returns "ZZ" for an unspecified region. +func (r Region) String() string { + return r.regionID.String() +} + +// ISO3 returns the 3-letter ISO code of r. +// Note that not all regions have a 3-letter ISO code. +// In such cases this method returns "ZZZ". +func (r Region) ISO3() string { + return r.regionID.ISO3() +} + +// M49 returns the UN M.49 encoding of r, or 0 if this encoding +// is not defined for r. +func (r Region) M49() int { + return r.regionID.M49() +} + +// IsPrivateUse reports whether r has the ISO 3166 User-assigned status. This +// may include private-use tags that are assigned by CLDR and used in this +// implementation. So IsPrivateUse and IsCountry can be simultaneously true. +func (r Region) IsPrivateUse() bool { + return r.regionID.IsPrivateUse() +} + +// IsCountry returns whether this region is a country or autonomous area. This +// includes non-standard definitions from CLDR. +func (r Region) IsCountry() bool { + return r.regionID.IsCountry() +} + +// IsGroup returns whether this region defines a collection of regions. This +// includes non-standard definitions from CLDR. +func (r Region) IsGroup() bool { + return r.regionID.IsGroup() +} + +// Contains returns whether Region c is contained by Region r. It returns true +// if c == r. +func (r Region) Contains(c Region) bool { + return r.regionID.Contains(c.regionID) +} + +// TLD returns the country code top-level domain (ccTLD). UK is returned for GB. +// In all other cases it returns either the region itself or an error. +// +// This method may return an error for a region for which there exists a +// canonical form with a ccTLD. To get that ccTLD canonicalize r first. The +// region will already be canonicalized it was obtained from a Tag that was +// obtained using any of the default methods. +func (r Region) TLD() (Region, error) { + tld, err := r.regionID.TLD() + return Region{tld}, err +} + +// Canonicalize returns the region or a possible replacement if the region is +// deprecated. It will not return a replacement for deprecated regions that +// are split into multiple regions. +func (r Region) Canonicalize() Region { + return Region{r.regionID.Canonicalize()} +} + +// Variant represents a registered variant of a language as defined by BCP 47. +type Variant struct { + variant string +} + +// ParseVariant parses and returns a Variant. An error is returned if s is not +// a valid variant. +func ParseVariant(s string) (Variant, error) { + v, err := language.ParseVariant(s) + return Variant{v.String()}, err +} + +// String returns the string representation of the variant. +func (v Variant) String() string { + return v.variant +} |