dbml-language-server 0.1.2

# DBML Language Server

A high-performance, standalone Language Server Protocol (LSP) implementation for [DBML (Database Markup Language)](https://dbml.dbdiagram.io/home/), written in Rust.

## Features

- 🔍 **Real-time Error Diagnostics** - Instant syntax and semantic validation with detailed error messages
- 🎨 **Semantic Syntax Highlighting** - Context-aware highlighting for tables, columns, enums, and relationships
- 🔗 **Go to Definition** - Navigate to table and column definitions with a single click
- ✏️ **Rename Refactoring** - Safely rename symbols across your entire schema
- 🛡️ **Robust Error Recovery** - Continue getting language features even with syntax errors
- ⚡ **High Performance** - Asynchronous architecture built on Tokio for responsive editing
- 🔌 **Editor Agnostic** - Works with any LSP-compatible editor (VS Code, Neovim, Vim, Emacs, Sublime Text, etc.)

## Installation

### From crates.io

```bash
cargo install dbml-lsp
```

### From Source

```bash
git clone https://github.com/your-username/dbml-lsp.git
cd dbml-lsp
cargo install --path .
```

### Pre-built Binaries

Download pre-built binaries from the [releases page](https://github.com/your-username/dbml-lsp/releases).

## Quick Start

### 1. Install the Server

```bash
cargo install dbml-lsp
```

### 2. Configure Your Editor

<details>
<summary><b>Visual Studio Code</b></summary>

Install a generic LSP extension or create a minimal one:

**Using settings.json:**

```json
{
    "dbml.lsp.path": "dbml-lsp"
}
```

Or use the [VS Code extension](https://marketplace.visualstudio.com/items?itemName=your-publisher/dbml-lsp) (coming soon).

</details>

<details>
<summary><b>Neovim</b></summary>

Add to your `init.lua`:

```lua
vim.api.nvim_create_autocmd('FileType', {
  pattern = 'dbml',
  callback = function()
    vim.lsp.start({
      name = 'dbml-lsp',
      cmd = {'dbml-lsp'},
      root_dir = vim.fs.dirname(vim.fs.find({'.git'}, { upward = true })[1]),
    })
  end,
})

-- Set filetype for .dbml files
vim.filetype.add({
  extension = { dbml = 'dbml' },
})
```

</details>

<details>
<summary><b>Vim (vim-lsp)</b></summary>

Add to your `.vimrc`:

```vim
if executable('dbml-lsp')
  au User lsp_setup call lsp#register_server({
    \ 'name': 'dbml-lsp',
    \ 'cmd': {server_info->['dbml-lsp']},
    \ 'allowlist': ['dbml'],
    \ })
endif

autocmd BufNewFile,BufRead *.dbml set filetype=dbml
```

</details>

<details>
<summary><b>Emacs (lsp-mode)</b></summary>

Add to your Emacs config:

```elisp
(require 'lsp-mode)

(add-to-list 'lsp-language-id-configuration '(dbml-mode . "dbml"))

(lsp-register-client
 (make-lsp-client
  :new-connection (lsp-stdio-connection "dbml-lsp")
  :major-modes '(dbml-mode)
  :server-id 'dbml-lsp))

(add-to-list 'auto-mode-alist '("\\.dbml\\'" . dbml-mode))
(add-hook 'dbml-mode-hook #'lsp)
```

</details>

<details>
<summary><b>Sublime Text</b></summary>

Install the LSP package, then add to LSP settings:

```json
{
    "clients": {
        "dbml-lsp": {
            "enabled": true,
            "command": ["dbml-lsp"],
            "selector": "source.dbml"
        }
    }
}
```

</details>

### 3. Test It Out

Create a file `example.dbml`:

```dbml
Table users {
  id int [pk, increment]
  username varchar(255) [unique, not null]
  email varchar(255) [unique, not null]
  created_at timestamp [default: `now()`]

  Indexes {
    (email) [unique]
    (created_at)
  }
}

Table posts {
  id int [pk, increment]
  user_id int [not null, ref: > users.id]
  title varchar(500) [not null]
  content text
  status post_status [default: 'draft']
  created_at timestamp [default: `now()`]
}

Enum post_status {
  draft
  published
  archived
}

Ref: posts.user_id > users.id
```

You should now see:

- ✅ Syntax highlighting
- ✅ Error diagnostics for invalid syntax
- ✅ Go to definition (click on table/column references)
- ✅ Rename refactoring (F2 on symbols)

## Supported DBML Features

| Feature        | Supported | Notes                                   |
| -------------- | --------- | --------------------------------------- |
| Tables         | ✅        | With columns, aliases, and settings     |
| Columns        | ✅        | All data types and settings             |
| Relationships  | ✅        | All types: `->`, `<`, `>`, `<>`         |
| Inline Refs    | ✅        | `[ref: > table.column]`                 |
| Composite Keys | ✅        | Multi-column foreign keys               |
| Enums          | ✅        | With members and notes                  |
| Indexes        | ✅        | Single, composite, and expression-based |
| Projects       | ✅        | Project metadata                        |
| Comments       | ✅        | Single-line `//` and multi-line `/* */` |
| Notes          | ✅        | Table and column notes                  |

## Architecture

### Technology Stack

- **[tower-lsp](https://github.com/ebkalderon/tower-lsp)** - Async LSP framework built on Tower and Tokio
- **[chumsky](https://github.com/zesterer/chumsky)** - Parser combinator library with excellent error recovery
- **[tokio](https://tokio.rs/)** - Async runtime for concurrent request handling
- **[dashmap](https://github.com/xacrimon/dashmap)** - Thread-safe concurrent HashMap for document caching

### Pipeline

```
DBML Source Code
       ↓
   Lexer (Tokenization)
       ↓
   Parser (AST Construction)
       ↓
   Semantic Analyzer (Symbol Resolution)
       ↓
   LSP Features (Diagnostics, Navigation, etc.)
```

The language server uses a multi-stage analysis pipeline:

1. **Lexical Analysis** - Tokenizes DBML source with comment handling
2. **Syntactic Analysis** - Builds an Abstract Syntax Tree with error recovery
3. **Semantic Analysis** - Creates symbol tables and validates relationships

This architecture ensures robust error handling and allows features to work even when the document contains syntax errors.

## Development

### Building

```bash
# Debug build
cargo build

# Release build (optimized)
cargo build --release

# The binary will be at:
# target/release/dbml-lsp
```

### Testing

```bash
# Run all tests
cargo test

# Run with output
cargo test -- --nocapture

# Run specific test
cargo test test_parse_simple_table

# Run with logging
RUST_LOG=debug cargo test
```

### Project Structure

```
dbml-lsp/
├── Cargo.toml          # Dependencies and project metadata
├── src/
│   ├── main.rs         # Entry point
│   ├── server.rs       # LSP server implementation
│   ├── state.rs        # Document state management
│   ├── ast.rs          # Abstract Syntax Tree definitions
│   └── analysis/       # Parsing and analysis pipeline
│       ├── mod.rs
│       ├── token.rs    # Token definitions
│       ├── lexer.rs    # Lexical analyzer
│       ├── parser.rs   # Parser implementation
│       └── semantic.rs # Semantic analyzer
└── tests/
    └── integration_tests.rs
```

## Troubleshooting

### Server Won't Start

```bash
# Check if the binary is executable
chmod +x $(which dbml-lsp)

# Verify it runs
dbml-lsp --version
```

### Enable Debug Logging

Set the `RUST_LOG` environment variable:

```bash
# In your editor config or terminal
RUST_LOG=debug dbml-lsp
```

**VS Code:** Check the Output panel → "DBML Language Server"

**Neovim:** `:LspLog`

### Features Not Working

1. Ensure the file has a `.dbml` extension
2. Check that the LSP client is configured correctly
3. Look for errors in your editor's LSP logs
4. Verify the server is running: check your editor's LSP status

## Performance

The server is designed for high performance:

- **Asynchronous**: Non-blocking request handling
- **Concurrent**: Multiple documents analyzed in parallel
- **Efficient**: In-memory caching with automatic cleanup
- **Scalable**: Handles large schemas (10,000+ lines)

Typical performance metrics:

- Parse time: ~5ms for 1000-line file
- Memory usage: ~50MB for 10 open documents
- Startup time: ~100ms

## Roadmap

### Planned Features

- [ ] **Code Completion** - Auto-complete for table names, columns, and keywords
- [ ] **Hover Information** - Show column types and relationship info on hover
- [ ] **Document Symbols** - Outline view of tables, enums, and relationships
- [ ] **Workspace Symbols** - Project-wide symbol search
- [ ] **Code Actions** - Quick fixes for common errors
- [ ] **Formatting** - Auto-format DBML files
- [ ] **Incremental Parsing** - Faster updates for large files
- [ ] **Signature Help** - Parameter hints for settings
- [ ] **Folding Ranges** - Collapse/expand table definitions

### Future Enhancements

- Multi-file project support
- Import/export to SQL
- Database introspection
- Diagram generation
- Schema validation rules
- Custom lint rules

## Contributing

Contributions are welcome! Here's how you can help:

1. **Report Bugs** - Open an issue with reproduction steps
2. **Suggest Features** - Describe your use case
3. **Submit PRs** - Fork, create a feature branch, and submit a PR
4. **Improve Docs** - Help make the documentation clearer
5. **Write Tests** - Increase test coverage

### Development Setup

```bash
# Clone the repository
git clone https://github.com/your-username/dbml-lsp.git
cd dbml-lsp

# Install dependencies
cargo build

# Run tests
cargo test

# Format code
cargo fmt

# Lint
cargo clippy
```

### Guidelines

- Follow Rust conventions and idioms
- Write tests for new features
- Update documentation
- Keep commits focused and descriptive
- Ensure `cargo test` passes before submitting

## License

This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.

## Acknowledgments

- Built with [tower-lsp](https://github.com/ebkalderon/tower-lsp) by Eyal Kalderon
- Parsing powered by [chumsky](https://github.com/zesterer/chumsky) by Joshua Barretto
- Inspired by the [DBML specification](https://dbml.dbdiagram.io/docs/) by Holistics
- Special thanks to the Rust LSP community for resources and examples

## Related Projects

- [dbdiagram.io](https://dbdiagram.io/) - Official DBML database designer
- [rust-analyzer](https://rust-analyzer.github.io/) - Inspiration for LSP architecture
- [tree-sitter-dbml](https://github.com/example/tree-sitter-dbml) - Tree-sitter grammar for DBML

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