Go Internationalization and Localization

An introduction to Go's text package, which allows developers to build localized applications and services.

Transcript

1. Hello, Verden! Go Cph 2 May 2018 Go internationalization and localization
2. Hej!Mit navn er Terin.
3. Localization is the act of adapting to meet local expectations
4. Internationalization is the design and implementation that enables localization
5. gettext(3)
6. printf(ngettext( "%s has one car.\n", "%s has %d cars.\n", num_cars ), name, num_cars );
7. Strings are extracted from the program's source into a Portable Object Template. xgettext -c main.c -o main.pot This results in main.pot. #: main.c:1 msgid "%s has one car.\n" msgid_plural "%s has %d cars.\n" msgstr[0] "" msgstr[1] ""
8. A translator can generate a Portable Object file. msginit --locale=da --input=main.pot Then translate da.po. #: main.c:1 msgid "%s has one car.\n" msgid_plural "%s has %d cars.\n" msgstr[0] "%s har en bil.\n" msgstr[1] "%s har %d biler.\n"
9. During the build step, Portable Object files are compiled into Machine Object files, and distributed with the software package. At runtime, the appropriate locale is displayed based on the setting of environment variables.
10. golang.org/x/text
11. Formatted Output import "golang.org/x/text/message" p := message.NewPrinter(language.Danish) p.Printf( "Hello, my name is %s. I have %d cars.\n", name, num_cars, ) "Hello, my name is Terin. I have 1.024 cars.\n"
12. Formatted Numerics import "golang.org/x/text/number" p.Printf("I have %v bytes.\n", number.Decimal(1024)) Formats this via the printer's locale: I have 1.024 bytes.
13. Formatted Numerics p.Printf( "The mass of the sun is %v kilograms.\n", number.Scientific(1.9891e30)) Formats this via the printer's locale: The mass of the sun is 2 × 10³⁰ kilograms.
14. Formatted Numerics p.Printf( "The maximum power output is %v watts.\n", number.Engineering(2e7)) Formats this via the printer's locale: The maximum power output is 20 × 10⁶ watts.
15. Formatted Currencies import "golang.org/x/text/currency" amount := currency.DKK.Amount(1234.56) p.Printf("Total: %v\n", currency.Symbol(amount)) Formats this via the printer's locale: Total: kr. 1234.56 ☹
16. Collations import "golang.org/x/text/collate" c := collate.New(language.Danish) strings := StringSlice{ []string{"åben", "adelig"}, } c.Sort(strings) // ["adelig", "åben"]
17. Locales • Composed of multiple parts, to define language, script, region, variants, and extensions. • Go uses BCP 47 language tags ◦ en ◦ en-DK ◦ da ◦ da-GL ◦ zh-Hans ◦ he-IL-u-ca-hebrew-tz-jeruslm
18. Locales import "golang.org/x/text/language" var l language.Tag l = language.English l = language.MustParse("he-IL-u-ca-hebrew-tz-jeruslm") p := message.NewPrinter(l)
19. HTTP Handler import "golang.org/x/text/language" matcher := language.NewMatcher([]language.Tag{ language.English, language.MustParse("en-AU"), language.Danish, language.Chinese, })
20. HTTP Handler handler(w http.ResponseWriter, r *http.Request) { lang, _ := r.Cookie("lang") accept := r.Header.Get("Accept-Language") tag, _ := language.MatchStrings( matcher, lang.String(), accept) p := message.NewPrinter(tag) p.Fprintln(w, "Hello World") }
21. CLI Application tag, err := language.Parse(os.Getenv("LANG")) if err != nil { tag = language.English } p := message.NewPrinter(tag) p.Printf(w, "Hello World")
22. Defining Translations Go defines translations in "catalogs" that are transparently used when formatting strings using the message printer.
23. Building a Catalog import "golang.org/x/text/message/catalog" l := language.Danish cat := catalog.NewBuilder() cat.SetString(l, "Hello, my name is %s.\n", "Hej, mit navn er %s.\n", ) p := message.NewPrinter(l, message.Catalog(cat))
24. Plurals import "golang.org/x/text/feature/plural" cat.Set( language.Danish, "I have %d cars.\n", plural.Selectf(1, "%d", "=0", "Jeg har ingen biler.\n", "one", "Jeg har en bil.\n", "other", "Jeg har %d biler.\n", ), )
25. Catalog Interface type Catalog interface { Languages() []language.Tag Matcher() language.Matcher Context(tag language.Tag, r catmsg.Renderer) *Context }
26. gotext go get golang.org/x/text/cmd/gotext/... • Go replacement for "gettext" ◦ Extract text from Go programs ◦ Update catalogs ◦ Code generation for loading catalogs
27. Future Work • Gender support • Date formatting • Much more!