i18nd — internalization library

The i18nd library is an internationalization (i18n) tool specifically designed for the D programming language. This library provides a suite of standard i18n functionalities to facilitate the development of globally accessible applications.

Key features of i18nd include:

• Interpolation: Allows dynamic insertion of values into strings, making it easier to adapt text for different languages and regions without changing the program logic.
• Formatting: Supports various data formats, including dates, numbers, and currencies, simplifying that these elements conform to the locale-specific conventions.
• Pluralization: Handles the complex rules of plural forms in different languages, enabling representation of quantity-related text.
• Nested Values: Supports nesting of translation strings, allowing for more organized and readable code, especially in the context of complex language constructs.
• Arrays: Efficiently manages arrays within translation strings, ensuring correct presentation of grouped data.
• References to Other Values: Facilitates the reuse of translation strings, enhancing consistency and reducing redundancy in the localization process.

Data for internationalization in the i18nd library is stored in JSON format, providing a familiar and flexible structure for managing translation strings and locale-specific data. This choice of format enhances the library's usability and integration with various data sources and systems.

Usage

First you need to connect the library to your project and add its import:

import i18nd;

Setting up Localization Data

First, load your JSON localization data using the set method:

import std.json;

auto json = parseJSON(`{
    "simpleKey": "Simple text",
    "nested": {
        "key": "Nested text"
    },
    "keyWithReference": "Reference: $t(nested.key)",
    "keyWithReplacements": "Name: {{name}}",
    "keyWithPlural": "{{count}} apple{{count.plural(_, s)}}",
    "formattedKey": "Number: {{number.format(%.2f)}}",
    "arrayKey": ["value1", "value2", "value{{number}}"]
}`);
i18n.set(json);

Basic Translation

Use the t method to translate a key:

string translated = i18n.t("simpleKey");
writeln(translated); // Outputs: Simple text

Interpolation

To replace placeholders with dynamic values:

string nameTranslation = i18n.t("keyWithReplacements", ["name": Value("Alice")]);
writeln(nameTranslation); // Outputs: Name: Alice

Pluralization

Handle different plural forms based on count:

string oneApple = i18n.t("keyWithPlural", ["count": Value(1)]);
string twoApples = i18n.t("keyWithPlural", ["count": Value(2)]);
writeln(oneApple); // Outputs: 1 apple
writeln(twoApples); // Outputs: 2 apples

The word form is selected based on the number of plural elements in the array and follows the following logic: [one, many] or [one, more, many], or [one, more, many, other]. If you need to use an empty insert (as in the example), use an underscore "_".

We are not sure if this is correct for all languages, if you know the best algorithm, then correct us.

Formatting

Format numbers, dates, etc., using the .format specifier:

string formattedNumber = i18n.t("formattedKey", ["number": Value(3.14159)]);
writeln(formattedNumber); // Outputs: Number: 3.14

Theoretically supports any formatting std.format.

Nested Values

Access nested keys in the JSON structure:

string nestedText = i18n.t("nested.key");
writeln(nestedText); // Outputs: Nested text

Arrays

Work with arrays in localization data:

string arrayValues = i18n.t("arrayKey", ["number": Value(3)]);
writeln(arrayValues); // Outputs: value1, value2, value3

References to Other Values

Utilize references to other localization values within a translation:

string refTranslation = i18n.t("keyWithReference");
writeln(refTranslation); // Outputs: Reference: Nested text

Contribution

Contributions to the i18nd library are welcome. Please ensure that your changes pass all existing unittests and add new tests for new features.