matterbridge/vendor/github.com/nicksnyder/go-i18n/i18n/language/language.go

100 lines
2.7 KiB
Go

// Package language defines languages that implement CLDR pluralization.
package language
import (
"fmt"
"strings"
)
// Language is a written human language.
type Language struct {
// Tag uniquely identifies the language as defined by RFC 5646.
//
// Most language tags are a two character language code (ISO 639-1)
// optionally followed by a dash and a two character country code (ISO 3166-1).
// (e.g. en, pt-br)
Tag string
*PluralSpec
}
func (l *Language) String() string {
return l.Tag
}
// MatchingTags returns the set of language tags that map to this Language.
// e.g. "zh-hans-cn" yields {"zh", "zh-hans", "zh-hans-cn"}
// BUG: This should be computed once and stored as a field on Language for efficiency,
// but this would require changing how Languages are constructed.
func (l *Language) MatchingTags() []string {
parts := strings.Split(l.Tag, "-")
var prefix, matches []string
for _, part := range parts {
prefix = append(prefix, part)
match := strings.Join(prefix, "-")
matches = append(matches, match)
}
return matches
}
// Parse returns a slice of supported languages found in src or nil if none are found.
// It can parse language tags and Accept-Language headers.
func Parse(src string) []*Language {
var langs []*Language
start := 0
for end, chr := range src {
switch chr {
case ',', ';', '.':
tag := strings.TrimSpace(src[start:end])
if spec := getPluralSpec(tag); spec != nil {
langs = append(langs, &Language{NormalizeTag(tag), spec})
}
start = end + 1
}
}
if start > 0 {
tag := strings.TrimSpace(src[start:])
if spec := getPluralSpec(tag); spec != nil {
langs = append(langs, &Language{NormalizeTag(tag), spec})
}
return dedupe(langs)
}
if spec := getPluralSpec(src); spec != nil {
langs = append(langs, &Language{NormalizeTag(src), spec})
}
return langs
}
func dedupe(langs []*Language) []*Language {
found := make(map[string]struct{}, len(langs))
deduped := make([]*Language, 0, len(langs))
for _, lang := range langs {
if _, ok := found[lang.Tag]; !ok {
found[lang.Tag] = struct{}{}
deduped = append(deduped, lang)
}
}
return deduped
}
// MustParse is similar to Parse except it panics instead of retuning a nil Language.
func MustParse(src string) []*Language {
langs := Parse(src)
if len(langs) == 0 {
panic(fmt.Errorf("unable to parse language from %q", src))
}
return langs
}
// Add adds support for a new language.
func Add(l *Language) {
tag := NormalizeTag(l.Tag)
pluralSpecs[tag] = l.PluralSpec
}
// NormalizeTag returns a language tag with all lower-case characters
// and dashes "-" instead of underscores "_"
func NormalizeTag(tag string) string {
tag = strings.ToLower(tag)
return strings.Replace(tag, "_", "-", -1)
}