ZeroI18n 1.0.0

ZeroI18n

ZeroI18n is a high-performance, zero-overhead compile-time internationalization (i18n) source generator for modern .NET.

It transforms Project Fluent (.ftl), ICU MessageFormat, and i18next files into strongly typed pure C# methods and switch pattern matches directly at compile time. Zero reflection, zero runtime allocations, zero external runtime dependencies, and 100% NativeAOT ready.

✨ Key Features

• ⚡ Zero Runtime Overhead: All localized templates are compiled into static C# switch expressions. No runtime file I/O, no JSON deserialization, and no AST interpretation.
• 🛡️ 100% NativeAOT & Trimming Friendly: Emits pure, static C# code with string literals. Completely safe for full trimming and Ahead-Of-Time compilation.
• 📦 Zero External Runtime Dependencies: Installs cleanly as an analyzer dependency (DevelopmentDependency). Shuts down dependency conflicts by embedding its own lightweight parser.
• 🌐 Modern Project Fluent Syntax: Full support for variables, plural categories ([one], [other]), selectors, attributes (.tooltip), and reusable terms (-brand).
• 🔄 Multi-Format Support:
  • Project Fluent (.ftl)
  • ICU MessageFormat (.json)
  • i18next (.json)
• 🎨 Type-Safe & Reactive UI Ready:
  • Strongly Typed APIs: Auto-infers method parameters (e.g. Messages.Welcome(userName: "Alice")).
  • Reactive UI Support: Emits a built-in LocalizationManager : INotifyPropertyChanged for seamless, live language switching in WPF, Avalonia, and .NET MAUI without app restarts.

⚡ 30-Second Quick Start

1. Install NuGet Package

dotnet add package ZeroI18n

2. Add Localization Files

Create a messages/ folder in your project root and add your .ftl files. ZeroI18n automatically detects and includes them:

messages/en.ftl:

-brand = ZeroI18n
app-name = { -brand } Demo

welcome = Welcome, { $userName }!

matched-records =
    { $count ->
        [one] Found { $count } record
       *[other] Found { $count } records
    }

login-button = Sign In
    .tooltip = Click to sign in with your account

messages/zh-CN.ftl:

-brand = ZeroI18n
app-name = { -brand } 示例

welcome = 欢迎，{ $userName }！

matched-records =
    { $count ->
       *[other] 找到 { $count } 条记录
    }

login-button = 登录
    .tooltip = 点击以登录您的账号

3. Use in C#

Upon build, ZeroI18n automatically generates the strongly typed Messages class:

using YourProject.I18n;

// 1. Strongly typed calls with parameter inference
string app = Messages.AppName();                         // "ZeroI18n Demo"
string greeting = Messages.Welcome("Alice");             // "Welcome, Alice!"
string countInfo = Messages.MatchedRecords(count: 3);    // "Found 3 records"

// Fluent attributes automatically generate composite methods
string tooltip = Messages.LoginButtonTooltip();          // "Click to sign in with your account"

// 2. Switch languages dynamically at runtime
Messages.CurrentLocale = "zh-CN";

Console.WriteLine(Messages.Welcome("Alice"));           // "欢迎，Alice！"
Console.WriteLine(Messages.LoginButton());              // "登录"
Console.WriteLine(Messages.LoginButtonTooltip());       // "点击以登录您的账号"

🖥️ Live UI Data Binding (WPF / Avalonia / .NET MAUI)

ZeroI18n generates an INotifyPropertyChanged-compliant LocalizationManager singleton. Changing CurrentLocale automatically triggers property change notifications, updating bound XAML elements instantly without restarting the application:

XAML Binding

<TextBlock Text="{Binding [app-name], Source={x:Static i18n:LocalizationManager.Instance}}" />
<Button Content="{Binding [login-button], Source={x:Static i18n:LocalizationManager.Instance}}"
        ToolTip.Tip="{Binding [login-button.tooltip], Source={x:Static i18n:LocalizationManager.Instance}}" />

Switching Language in Code / ViewModel

// Updates CurrentLocale and refreshes all bound XAML elements automatically
LocalizationManager.Instance.CurrentLocale = "zh-CN";

// Or directly via static class:
Messages.CurrentLocale = "zh-CN";

📁 File Conventions & Format Detection

ZeroI18n infers the target locale from the file name (without extension). For instance, en.ftl maps to en, and zh-CN.json maps to zh-CN:

⚙️ MSBuild Configuration

You can customize the generated class name, namespace, accessibility, and fallback locale directly in your .csproj:

<PropertyGroup>
  
  <ZeroI18nClassName>AppStrings</ZeroI18nClassName>

  
  <ZeroI18nNamespace>MyCompany.MyApp.Localization</ZeroI18nNamespace>

  
  <ZeroI18nAccessModifier>public</ZeroI18nAccessModifier>

  
  <ZeroI18nDefaultLocale>zh-CN</ZeroI18nDefaultLocale>

  
  <EnableZeroI18n>true</EnableZeroI18n>
</PropertyGroup>

🔍 Compile-Time Diagnostics

ZeroI18n performs strict syntactic validation at compile time, catching errors early during the build:

📄 License

This project is licensed under the MIT License.