# i18n - translations module for Go

i18n is a set of functions to help with project translations and language detection.

## Usage

First get the module:

    go get go.deck17.com/i18n


Import the the module in the final project:

    import (
        "go.deck17.com/i18n"
        "go.deck17.com/i18n/detect"
    )


## Translate text

i18n exports a single constructor that accepts a map[string]map[string]string with language and translations maps. As
a result it returns two funcs, each accepting language code as a string, key to translate and optional arguments for
string substitution (as formatted by fmt.Sprintf). The returned functions are defined as:

    func(string, string, args ...any) string
    func(string, string, args ...any) error

### Initialize translator

This is an example how to initialize the translator:

    var translations = map[string]map[string]string{
        "en": {
            "hello": "Hello World!",
        },
        "de": {
            "hello": "Hallo, Welt!",
        },
    }

    // in this case "en" is the default language
    var T, Terr = i18n.NewTranslator(translations, "en")


### Use translator in the code

Translate text inside Go code:

    fmt.Printf("Translated text (en): %s\n", T("en", "hello"))
    fmt.Printf("Translated text (de): %s\n", T("de", "hello"))

### Translated error messages

Similarly, Terr can be used to generate localized error messages instead of strings:

    func do_stuff() error {
        return Terr("en", "hello")
    }


## Detecting language in http server applications

The i18n/detect module contains a function that can be used to detect currently selected web language. It uses query
string and cookies to do so and automatically sends / updates cookie when language is changed (with query parameter).

    // the first language in the list is used as a default language
    var detectLanguage = detect.NewHttpDetector(
        []string{"en", "de"}, // list of languages
        "/",                  // cookie path
        31536000,             // max age in seconds
    }

The result function detectLanguage accepts http.ResponseWriter and \*http.Request arguments and returns string with
language code.