68 lines
1.9 KiB
Go
68 lines
1.9 KiB
Go
// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package internal
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// This file contains matchers that implement CLDR inheritance.
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//
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// See https://unicode.org/reports/tr35/#Locale_Inheritance.
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//
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// Some of the inheritance described in this document is already handled by
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// the cldr package.
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import (
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"golang.org/x/text/language"
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)
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// TODO: consider if (some of the) matching algorithm needs to be public after
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// getting some feel about what is generic and what is specific.
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// NewInheritanceMatcher returns a matcher that matches based on the inheritance
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// chain.
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//
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// The matcher uses canonicalization and the parent relationship to find a
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// match. The resulting match will always be either Und or a language with the
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// same language and script as the requested language. It will not match
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// languages for which there is understood to be mutual or one-directional
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// intelligibility.
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//
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// A Match will indicate an Exact match if the language matches after
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// canonicalization and High if the matched tag is a parent.
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func NewInheritanceMatcher(t []language.Tag) *InheritanceMatcher {
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tags := &InheritanceMatcher{make(map[language.Tag]int)}
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for i, tag := range t {
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ct, err := language.All.Canonicalize(tag)
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if err != nil {
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ct = tag
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}
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tags.index[ct] = i
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}
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return tags
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}
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type InheritanceMatcher struct {
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index map[language.Tag]int
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}
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func (m InheritanceMatcher) Match(want ...language.Tag) (language.Tag, int, language.Confidence) {
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for _, t := range want {
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ct, err := language.All.Canonicalize(t)
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if err != nil {
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ct = t
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}
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conf := language.Exact
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for {
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if index, ok := m.index[ct]; ok {
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return ct, index, conf
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}
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if ct == language.Und {
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break
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}
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ct = ct.Parent()
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conf = language.High
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}
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}
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return language.Und, 0, language.No
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}
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