| // 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 internal |
| |
| // This file contains matchers that implement CLDR inheritance. |
| // |
| // See https://unicode.org/reports/tr35/#Locale_Inheritance. |
| // |
| // Some of the inheritance described in this document is already handled by |
| // the cldr package. |
| |
| import ( |
| "golang.org/x/text/language" |
| ) |
| |
| // TODO: consider if (some of the) matching algorithm needs to be public after |
| // getting some feel about what is generic and what is specific. |
| |
| // NewInheritanceMatcher returns a matcher that matches based on the inheritance |
| // chain. |
| // |
| // The matcher uses canonicalization and the parent relationship to find a |
| // match. The resulting match will always be either Und or a language with the |
| // same language and script as the requested language. It will not match |
| // languages for which there is understood to be mutual or one-directional |
| // intelligibility. |
| // |
| // A Match will indicate an Exact match if the language matches after |
| // canonicalization and High if the matched tag is a parent. |
| func NewInheritanceMatcher(t []language.Tag) *InheritanceMatcher { |
| tags := &InheritanceMatcher{make(map[language.Tag]int)} |
| for i, tag := range t { |
| ct, err := language.All.Canonicalize(tag) |
| if err != nil { |
| ct = tag |
| } |
| tags.index[ct] = i |
| } |
| return tags |
| } |
| |
| type InheritanceMatcher struct { |
| index map[language.Tag]int |
| } |
| |
| func (m InheritanceMatcher) Match(want ...language.Tag) (language.Tag, int, language.Confidence) { |
| for _, t := range want { |
| ct, err := language.All.Canonicalize(t) |
| if err != nil { |
| ct = t |
| } |
| conf := language.Exact |
| for { |
| if index, ok := m.index[ct]; ok { |
| return ct, index, conf |
| } |
| if ct == language.Und { |
| break |
| } |
| ct = ct.Parent() |
| conf = language.High |
| } |
| } |
| return language.Und, 0, language.No |
| } |