@manifesto-ai/mel-lsp

Language Server Protocol implementation for MEL (Manifesto Expression Language).

Features

Phase 1 — Basic IDE Support

• Diagnostics — Real-time error and warning reporting via @manifesto-ai/compiler
• Completion — Context-aware suggestions for 150+ builtin functions, domain symbols, keywords, and system identifiers ($system, $meta, $input, $item)
• Hover — Documentation for builtins, keywords, and domain symbols
• Signature Help — Parameter hints for function calls
• Document Symbols — Outline of state, computed, action, and type declarations

Phase 2 — Advanced Navigation

• Go to Definition — Jump to symbol declarations
• Find References — Locate all usages of a symbol
• Rename Symbol — Safe rename across all occurrences
• Semantic Tokens — AST-based syntax highlighting
• Code Actions — Quick fixes with fuzzy typo suggestions

Phase 3 — AI-Native Schema Introspection

• mel/schemaIntrospection — Returns full compiled DomainSchema (state, computed, actions, types)
• mel/actionSignatures — Lightweight action metadata for LLM agent integration

Installation

npm install @manifesto-ai/mel-lsp

Usage

As a standalone server

npx mel-lsp

The server communicates over stdio using the LSP protocol.

VS Code Extension

The vscode-mel extension is included in the vscode-mel/ directory.

1. Open the vscode-mel/ folder in VS Code
2. Press F5 to launch the Extension Development Host
3. Open any .mel file to activate the language server

Extension features:

• Syntax highlighting via TextMate grammar
• Full LSP integration (completions, hover, diagnostics, etc.)
• File watching for **/*.mel files

With other editors

Any editor that supports LSP can use mel-lsp. Configure your editor to launch mel-lsp over stdio for files with the .mel extension.

Development

pnpm install          # Install dependencies
pnpm build            # Build with tsup
pnpm dev              # Build in watch mode
pnpm test             # Run tests
pnpm test:watch       # Run tests in watch mode

Architecture

src/
├── server.ts              # Main server entry point
├── capabilities.ts        # LSP capability declarations
├── compiler-bridge.ts     # @manifesto-ai/compiler wrapper with schema caching
├── document-manager.ts    # Document tracking
├── ast-utils.ts           # AST analysis utilities (scope, symbols)
├── registry/
│   ├── builtins.ts        # 150+ builtin function definitions
│   └── keywords.ts        # Keywords, system identifiers, snippets
└── providers/
    ├── diagnostics.ts     # Error/warning publishing
    ├── completion.ts      # Autocomplete
    ├── hover.ts           # Hover information
    ├── signature.ts       # Function parameter hints
    ├── symbols.ts         # Document outline
    ├── definition.ts      # Go to definition
    ├── references.ts      # Find all references
    ├── rename.ts          # Rename symbol
    ├── semantic-tokens.ts # AST-based highlighting
    ├── code-actions.ts    # Quick fixes
    └── introspection.ts   # AI schema introspection

License

MIT