translation (i18) / localisation (l10n) support

[amitu]

• basic lang global
• <package-name>/lang so any package can use any other package's lang stuff
• <package-name>/lang/<foo> imports should also work

Changes

• AmitU, 12th Dec 2023: changed i18n to lang, as lang is auto import alias, and also lang handles both i18n and l10n concerns.

All Translations In Single Package

-- import: fastn
-- fastn.package: slides.fifthtry.com
default-lang: en
lang: slides.fifthtry.com/my-lang-files

We are introducing one key lang, which must be the folder in which translation files are present, eg in this case we have my-lang-files folder, which should contain files like en.ftd (or en-us.ftd, en-in.ftd), hi.ftd and so on.

Each Translation In Individual Package

-- import: fastn
-- fastn.package: slides.fifthtry.com
lang-en: slides.fifthtry.com/my-en-strings
lang-hi: slides-hi.fifthtry.com

-- fastn.dependency: slides-hi.fifthtry.com

You can mix and match also:

-- import: fastn
-- fastn.package: slides.fifthtry.com
lang: slides.fifthtry.com/my-i18n-files
lang-hi: slides-hi.fifthtry.com

-- fastn.dependency: slides-hi.fifthtry.com

In this setup, hi translation will be found in lang-hi module, and all other languages will be looked in my-lang-files folder (if hi.ftd is present in my-lang-files, then this would be a compilation error).

All modules must match

Basically it is a compilation error if some key is present in one language file but not in another.

Localisation Helpers

ftd.lang.hi.number_to_string() etc will localise a number to string.

Language Detection / Activation

fastn will honour a cookie fastn_lang, with the language that user has currently selected. If cookie is missing we will look at request header and figure out the best language match.

lang "system"

Any package that has language configured using lang keys, will have access to lang auto imported module, which will point to the language module for the current request.

Language Files Do Not Just Contain Strings

They can contain functions, ftd.image-src or even components.

This Is Not Content Translation

This feature can be used for content translation, but it is largely meant for translating fastn powered user interfaces.

Content translation imposes additional requirements, like each language must have a searchable permanent URL. This scheme uses same URL for content, and uses cookie/accept-lang header to switch language. If you are writing a blog or a book and want it translated in multiple language, wait for the content translation feature.

[Arpita-Jaiswal]

The default language should be decided by top-level package, if that language is not available then fallback to default of dependency package.