FRG Language Support

Visual Studio Code language support for FRG files - a custom language for defining API handlers, types, and services with Go code generation.

Features

🎨 Syntax Highlighting

• Comprehensive syntax highlighting for all FRG language constructs
• Support for keywords: syntax, info, import, type, enum, struct, service, returns
• Built-in types: string, bool, int, int32, int64, float, float32, float64, double, map, array, any, interface{}
• Decorators: @handler, @attr, @externDefs
• HTTP methods: get, post, put, delete, patch
• Enhanced comment highlighting with keyword support (// summary:, // tags:, etc.)
• Go struct tags highlighting

🔍 Navigation & Search

• Go to Definition (F12)
  • Jump from @handler names to Go function implementations
  • Navigate between type/enum definitions and their usages
• Find All References (Shift+F12)
  • Quickly find where types and enums are used
• Document Symbol Provider
  • Outline view with breadcrumbs
  • Navigate to services, handlers, types, enums

📝 Code Editing

• Document Formatting (Shift+Alt+F / Shift+Opt+F)
  • Auto-align fields in type and struct blocks
  • 4-space indentation
  • Preserves comments and structure
• Range Formatting - Format selected text only
• Import File Links - Clickable import paths
• Reference Code Lens - Shows reference count above type/enum definitions

Example

syntax = "v1"

info(
    title: "Demo API"
    desc: "A comprehensive FRG language example"
    version: "v1.0.0"
)

type User {
    ID       string  `json:"id"`
    Email    string  `json:"email" validate:"email"`
    Status   UserStatus `json:"status"`
}

enum UserStatus {
    Active   = 1; // Active user
    Inactive = 2; // Inactive user
}

@attr(
    group: "users"
    desc: "User management operations"
)
service {
    // summary: Get user by ID
    // tags: Users
    @handler getUser
    get /api/v1/users/:id() returns(User)

    // summary: Create new user
    // tags: Users
    @handler createUser
    post /api/v1/users(User) returns(User)
}

Requirements

• Visual Studio Code version 1.75.0 or higher

Installation

This extension is available on the Visual Studio Marketplace. To install:

1. Open VS Code
2. Press Ctrl+P / Cmd+P to open the Quick Open dialog
3. Enter ext install frg-language-support
4. Reload VS Code when prompted

Development

# Install dependencies
npm install

# Compile TypeScript
npm run compile

# Watch mode for development
npm run watch

# Prepare for publishing
npm run vscode:prepublish

File Structure

src/
├── extension.ts              # Main entry point
├── providers/                # Language feature providers
│   ├── definitionProvider.ts      # Go to Definition
│   ├── documentLinkProvider.ts    # Import file links
│   ├── referenceProvider.ts       # Find References
│   ├── codeLensProvider.ts        # Reference count
│   ├── documentSymbolProvider.ts  # Outline view
│   └── formattingProvider.ts      # Document formatting
└── utils/                    # Utilities
    ├── helpers.ts               # Shared functions
    └── formatter.ts             # Formatting logic

License

MIT

Support

For issues, questions, or contributions, please visit GitHub Repository.