Demo for using "x/text" package to support different plural translations

modules/translation/plural_test.go

@@ -0,0 +1,97 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package translation
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"golang.org/x/text/feature/plural"
+	"golang.org/x/text/language"
+	"golang.org/x/text/message/catalog"
+)
+
+func matchInt(l language.Tag, v any) plural.Form {
+	digits := []byte(fmt.Sprint(v))
+	for i := range digits {
+		digits[i] -= '0'
+	}
+	return plural.Cardinal.MatchDigits(l, digits, len(digits), 0)
+}
+
+var formsAll = []plural.Form{
+	plural.Zero,
+	plural.One,
+	plural.Two,
+	plural.Few,
+	plural.Many,
+	plural.Other,
+}
+
+func supportedForms(l language.Tag) (forms []plural.Form) {
+	cat := catalog.NewBuilder()
+	for _, form := range formsAll {
+		err := cat.Set(l, "%d test", plural.Selectf(1, "%d", form, "%d test"))
+		if err == nil {
+			forms = append(forms, form)
+		}
+	}
+	return forms
+}
+
+func TrPlural(langTag language.Tag, format string, args ...any) string {
+	// HINT: this is for demo purpose only, not optimized
+	form := plural.Other
+	forms := supportedForms(langTag)
+	for _, arg := range args {
+		switch arg.(type) {
+		case int, int64:
+			form = matchInt(langTag, arg)
+		}
+	}
+	p1 := strings.Index(format, "$[")
+	p2 := strings.Index(format, "]")
+	if p1 != -1 && p2 != -1 && p1 < p2 {
+		words := strings.Split(format[p1+2:p2], ",")
+		word := words[len(words)-1]
+		for i := range words {
+			if forms[i] == form {
+				word = words[i]
+			}
+		}
+		format = format[:p1] + strings.TrimSpace(word) + format[p2+1:]
+	}
+	return fmt.Sprintf(format, args...)
+}
+
+func TestPlural(t *testing.T) {
+	msg := TrPlural(language.English, "%d $[one, other]", 0)
+	assert.Equal(t, "0 other", msg)
+	msg = TrPlural(language.English, "%d $[one, other]", 1)
+	assert.Equal(t, "1 one", msg)
+	msg = TrPlural(language.English, "%d $[one, other]", 2)
+	assert.Equal(t, "2 other", msg)
+
+	msg = TrPlural(language.Latvian, "%d $[zero, one, other]", 0)
+	assert.Equal(t, "0 zero", msg)
+	msg = TrPlural(language.Latvian, "%d $[zero, one, other]", 1)
+	assert.Equal(t, "1 one", msg)
+	msg = TrPlural(language.Latvian, "%d $[zero, one, other]", 2)
+	assert.Equal(t, "2 other", msg)
+
+	msg = TrPlural(language.Arabic, "%d $[zero, one, two, few, many, other]", 0)
+	assert.Equal(t, "0 zero", msg)
+	msg = TrPlural(language.Arabic, "%d $[zero, one, two, few, many, other]", 1)
+	assert.Equal(t, "1 one", msg)
+	msg = TrPlural(language.Arabic, "%d $[zero, one, two, few, many, other]", 2)
+	assert.Equal(t, "2 two", msg)
+	msg = TrPlural(language.Arabic, "%d $[zero, one, two, few, many, other]", 3)
+	assert.Equal(t, "3 few", msg)
+	msg = TrPlural(language.Arabic, "%d $[zero, one, two, few, many, other]", 11)
+	assert.Equal(t, "11 many", msg)
+	msg = TrPlural(language.Arabic, "%d $[zero, one, two, few, many, other]", 100)
+	assert.Equal(t, "100 other", msg)
+}