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Using with Ruby LSP

Ruby LSP provides IDE features like autocomplete, go-to-definition, and inline diagnostics for Ruby code. When combined with T-Ruby, you get rich IDE support powered by type information from your .rbs files.

What is Ruby LSP?

Ruby LSP is a Language Server Protocol implementation for Ruby that provides:

Autocomplete - Intelligent code completion
Go to Definition - Navigate to method/class definitions
Hover Information - View type signatures and documentation
Diagnostics - Inline type errors and warnings
Code Actions - Quick fixes and refactorings
Document Symbols - Outline view of file structure

Installation

VS Code

Install the official Ruby LSP extension:

Open VS Code
Go to Extensions (Ctrl+Shift+X)
Search for "Ruby LSP"
Install the extension by Shopify

Or install via command line:

code --install-extension Shopify.ruby-lsp

Other Editors

Ruby LSP works with any editor supporting LSP:

Neovim: Use nvim-lspconfig
Emacs: Use lsp-mode or eglot
Sublime Text: Use LSP package
IntelliJ: Built-in Ruby support

Basic Setup for T-Ruby

Step 1: Install Ruby LSP Gem

gem install ruby-lsp

Or add to Gemfile:

group :development do
  gem "ruby-lsp"
  gem "t-ruby"
end

Step 2: Compile T-Ruby Code

Generate RBS files for type information:

trc compile src/

This creates:

build/          # Compiled Ruby files
sig/            # RBS type signatures

Step 3: Configure Ruby LSP

Create .vscode/settings.json:

{
  "rubyLsp.enabledFeatures": {
    "diagnostics": true,
    "formatting": true,
    "documentSymbols": true,
    "hover": true,
    "completion": true,
    "codeActions": true
  },
  "rubyLsp.indexing": {
    "includedPatterns": ["**/*.rb", "**/*.trb"],
    "excludedPatterns": ["**/test/**", "**/vendor/**"]
  }
}

Step 4: Configure RBS Path

Tell Ruby LSP where to find RBS signatures:

{
  "rubyLsp.rbs": {
    "enabled": true,
    "path": "sig"
  }
}

T-Ruby-Specific Configuration

Working with .trb Files

Configure VS Code to treat .trb files as Ruby:

.vscode/settings.json
{
  "files.associations": {
    "*.trb": "ruby"
  },
  "rubyLsp.indexing": {
    "includedPatterns": ["**/*.rb", "**/*.trb"]
  }
}

Syntax Highlighting

For better T-Ruby syntax highlighting, create a TextMate grammar or use Ruby highlighting with custom rules:

{
  "editor.tokenColorCustomizations": {
    "textMateRules": [
      {
        "scope": "storage.type.ruby",
        "settings": {
          "foreground": "#569CD6"
        }
      }
    ]
  }
}

Workspace Settings

For project-specific configuration:

.vscode/settings.json
{
  // Ruby LSP
  "rubyLsp.enabled": true,
  "rubyLsp.rubyVersionManager": "auto",

  // T-Ruby integration
  "rubyLsp.rbs": {
    "enabled": true,
    "path": "sig"
  },

  // File associations
  "files.associations": {
    "*.trb": "ruby"
  },

  // Formatting
  "editor.formatOnSave": true,
  "[ruby]": {
    "editor.defaultFormatter": "Shopify.ruby-lsp"
  },

  // Diagnostics
  "rubyLsp.enabledFeatures": {
    "diagnostics": true,
    "hover": true,
    "completion": true
  }
}

IDE Features with T-Ruby

Autocomplete

Ruby LSP provides intelligent autocomplete using RBS types:

user.trb
class User
  @name: String
  @email: String

  def initialize(name: String, email: String): void
    @name = name
    @email = email
  end

  def greet: String
    "Hello, #{@name}!"
  end
end

user = User.new("Alice", "alice@example.com")
user.   # <- Autocomplete shows: greet, name, email

After compiling, Ruby LSP reads sig/user.rbs and provides:

Method suggestions
Parameter types
Return types

Go to Definition

Navigate from usage to definition:

user = User.new("Alice", "alice@example.com")
#      ^^^^ Cmd+Click to jump to User class definition

result = user.greet
#            ^^^^^ Cmd+Click to jump to greet method

Hover Information

Hover over symbols to see type information:

def process_user(user: User): String
  # Hover over 'user' shows: User
  # Hover over method shows: (User) -> String
  user.greet
end

Inline Diagnostics

See type errors inline as you code:

def greet(name: String): String
  name.upcase
end

# Error shown inline:
greet(123)  # Expected String, got Integer
      ^^^

Code Actions

Quick fixes and refactorings:

class User
  def initialize(name: String): void
    @name = name
  end
  # 💡 Code action: "Add type annotation for @name"
end

Document Symbols

Outline view shows structure:

User (class)
  ├─ @name: String
  ├─ @email: String
  ├─ initialize(name, email)
  ├─ greet()
  └─ update_email(email)

Integration with Steep

For enhanced type checking, use Ruby LSP with Steep:

Install Steep

gem install steep

Configure Steepfile

target :app do
  check "build"
  signature "sig"
end

Configure Ruby LSP to Use Steep

.vscode/settings.json
{
  "rubyLsp.typechecker": "steep",
  "rubyLsp.rbs": {
    "enabled": true,
    "path": "sig"
  }
}

Now Ruby LSP will use Steep for type checking, providing:

Real-time type errors
More sophisticated type inference
Better autocomplete

Workflow with Ruby LSP

Development Workflow

Edit T-Ruby file in VS Code
Save file - T-Ruby watch compiles automatically
See updates - Ruby LSP refreshes diagnostics
Get autocomplete - Based on updated RBS

Setup Watch Mode

Use T-Ruby watch to auto-compile on save:

trc watch src/ --exec "echo 'Compiled'"

Configure VS Code to run this on startup:

.vscode/tasks.json
{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "T-Ruby Watch",
      "type": "shell",
      "command": "trc watch src/ --clear",
      "isBackground": true,
      "problemMatcher": [],
      "presentation": {
        "reveal": "never",
        "panel": "dedicated"
      },
      "runOptions": {
        "runOn": "folderOpen"
      }
    }
  ]
}

Advanced Configuration

Custom RBS Paths

If you have multiple RBS directories:

{
  "rubyLsp.rbs": {
    "enabled": true,
    "paths": [
      "sig/generated",
      "sig/manual",
      "vendor/rbs"
    ]
  }
}

Formatter Settings

Configure formatting for T-Ruby files:

{
  "[ruby]": {
    "editor.defaultFormatter": "Shopify.ruby-lsp",
    "editor.formatOnSave": true,
    "editor.tabSize": 2,
    "editor.insertSpaces": true
  }
}

Diagnostics Settings

Customize diagnostic display:

{
  "rubyLsp.diagnostics": {
    "severity": {
      "type_error": "error",
      "warning": "warning",
      "hint": "information"
    }
  },
  "problems.decorations.enabled": true
}

Performance Settings

For large projects, optimize performance:

{
  "rubyLsp.indexing": {
    "includedPatterns": ["src/**/*.trb", "src/**/*.rb"],
    "excludedPatterns": [
      "**/test/**",
      "**/spec/**",
      "**/vendor/**",
      "**/node_modules/**",
      "**/tmp/**"
    ]
  },
  "rubyLsp.experimental": {
    "parallelIndexing": true
  }
}

Other Editor Configurations

Neovim

With nvim-lspconfig:

-- init.lua
local lspconfig = require('lspconfig')

lspconfig.ruby_lsp.setup({
  cmd = { "bundle", "exec", "ruby-lsp" },
  filetypes = { "ruby", "trb" },
  init_options = {
    enabledFeatures = {
      "diagnostics",
      "formatting",
      "documentSymbols",
      "hover",
      "completion",
      "codeActions"
    },
    rbs = {
      enabled = true,
      path = "sig"
    }
  }
})

-- Treat .trb as Ruby
vim.filetype.add({
  extension = {
    trb = "ruby"
  }
})

Emacs

With lsp-mode:

;; init.el
(use-package lsp-mode
  :hook ((ruby-mode . lsp))
  :config
  (setq lsp-ruby-lsp-rbs-enabled t)
  (setq lsp-ruby-lsp-rbs-path "sig")
  (add-to-list 'auto-mode-alist '("\\.trb\\'" . ruby-mode)))

Sublime Text

Ruby LSP.sublime-settings
{
  "clients": {
    "ruby-lsp": {
      "enabled": true,
      "command": ["bundle", "exec", "ruby-lsp"],
      "selector": "source.ruby",
      "initializationOptions": {
        "enabledFeatures": {
          "diagnostics": true,
          "hover": true,
          "completion": true
        },
        "rbs": {
          "enabled": true,
          "path": "sig"
        }
      }
    }
  }
}

Troubleshooting

Ruby LSP Not Working

Problem: No autocomplete or diagnostics.

Solution:

Check Ruby LSP is running:
```
ps aux | grep ruby-lsp
```
Restart Ruby LSP in VS Code:
- Cmd+Shift+P → "Ruby LSP: Restart"
Check output panel:
- View → Output → Select "Ruby LSP"

RBS Files Not Found

Problem: Ruby LSP doesn't find type information.

Solution:

Verify RBS files exist:
```
ls sig/
```

Check RBS path in settings:

{
  "rubyLsp.rbs": {
    "enabled": true,
    "path": "sig"
  }
}

Reload VS Code window:
- Cmd+Shift+P → "Developer: Reload Window"

Outdated Diagnostics

Problem: Diagnostics don't update after compilation.

Solution:

Ensure T-Ruby watch is running:
```
trc watch src/
```
Manually refresh Ruby LSP:
- Save file (Cmd+S)
- Or restart Ruby LSP

Performance Issues

Problem: Editor is slow with Ruby LSP.

Solution:

Exclude unnecessary directories:

{
  "rubyLsp.indexing": {
    "excludedPatterns": [
      "**/vendor/**",
      "**/node_modules/**",
      "**/tmp/**"
    ]
  }
}

Disable unused features:

{
  "rubyLsp.enabledFeatures": {
    "diagnostics": true,
    "hover": true,
    "completion": true,
    "formatting": false,
    "codeActions": false
  }
}

Type Information Missing

Problem: No type info shown on hover.

Solution:

Verify RBS was generated:
```
cat sig/user.rbs
```

Check hover is enabled:

{
  "rubyLsp.enabledFeatures": {
    "hover": true
  }
}

Ensure RBS is valid:
```
rbs validate sig/
```

Best Practices

1. Keep Ruby LSP Running

Start Ruby LSP automatically with VS Code workspace.

2. Use Watch Mode

Always run T-Ruby watch during development:

trc watch src/ --clear

3. Commit RBS Files

Keep RBS files in version control for team members:

git add sig/
git commit -m "Update RBS signatures"

4. Configure for Performance

Exclude unnecessary directories in large projects:

{
  "rubyLsp.indexing": {
    "excludedPatterns": ["**/vendor/**", "**/tmp/**"]
  }
}

5. Use Steep Integration

For best type checking, enable Steep:

{
  "rubyLsp.typechecker": "steep"
}

Complete VS Code Setup

Here's a complete VS Code configuration for T-Ruby development:

.vscode/settings.json
{
  // Ruby LSP configuration
  "rubyLsp.enabled": true,
  "rubyLsp.rubyVersionManager": "auto",
  "rubyLsp.typechecker": "steep",

  // RBS integration
  "rubyLsp.rbs": {
    "enabled": true,
    "path": "sig"
  },

  // Features
  "rubyLsp.enabledFeatures": {
    "diagnostics": true,
    "formatting": true,
    "documentSymbols": true,
    "hover": true,
    "completion": true,
    "codeActions": true,
    "inlayHints": true
  },

  // Indexing
  "rubyLsp.indexing": {
    "includedPatterns": ["src/**/*.rb", "src/**/*.trb"],
    "excludedPatterns": [
      "**/test/**",
      "**/spec/**",
      "**/vendor/**",
      "**/tmp/**"
    ]
  },

  // File associations
  "files.associations": {
    "*.trb": "ruby"
  },

  // Formatting
  "editor.formatOnSave": true,
  "[ruby]": {
    "editor.defaultFormatter": "Shopify.ruby-lsp",
    "editor.tabSize": 2,
    "editor.insertSpaces": true
  },

  // Editor appearance
  "editor.inlayHints.enabled": "on",
  "problems.decorations.enabled": true,

  // Terminal
  "terminal.integrated.env.osx": {
    "RUBYOPT": "-W0"
  }
}

.vscode/tasks.json
{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "T-Ruby Watch",
      "type": "shell",
      "command": "trc watch src/ --clear",
      "isBackground": true,
      "problemMatcher": [],
      "presentation": {
        "reveal": "never",
        "panel": "dedicated"
      },
      "runOptions": {
        "runOn": "folderOpen"
      }
    },
    {
      "label": "Steep Watch",
      "type": "shell",
      "command": "steep watch --code=build --signature=sig",
      "isBackground": true,
      "problemMatcher": [],
      "presentation": {
        "reveal": "never",
        "panel": "dedicated"
      }
    }
  ]
}

.vscode/extensions.json
{
  "recommendations": [
    "shopify.ruby-lsp",
    "rebornix.ruby",
    "castwide.solargraph"
  ]
}

Keyboard Shortcuts

Useful VS Code shortcuts when using Ruby LSP:

Action	Shortcut (Mac)	Shortcut (Windows/Linux)
Go to Definition	Cmd+Click	Ctrl+Click
Go to Definition	F12	F12
Peek Definition	Alt+F12	Alt+F12
Find References	Shift+F12	Shift+F12
Rename Symbol	F2	F2
Format Document	Shift+Alt+F	Shift+Alt+F
Show Hover	Cmd+K Cmd+I	Ctrl+K Ctrl+I
Trigger Suggest	Ctrl+Space	Ctrl+Space
Quick Fix	Cmd+.	Ctrl+.
Restart LSP	Cmd+Shift+P → "Ruby LSP: Restart"	Ctrl+Shift+P → "Ruby LSP: Restart"

Next Steps

Using Steep - Enhanced type checking
RBS Integration - Learn about RBS files
Ruby LSP Documentation - Official docs

What is Ruby LSP?​

Installation​

VS Code​

Other Editors​

Basic Setup for T-Ruby​

Step 1: Install Ruby LSP Gem​

Step 2: Compile T-Ruby Code​

Step 3: Configure Ruby LSP​

Step 4: Configure RBS Path​

T-Ruby-Specific Configuration​

Working with .trb Files​

Syntax Highlighting​

Workspace Settings​

IDE Features with T-Ruby​

Autocomplete​

Go to Definition​

Hover Information​

Inline Diagnostics​

Code Actions​

Document Symbols​

Integration with Steep​

Install Steep​

Configure Steepfile​

Configure Ruby LSP to Use Steep​

Workflow with Ruby LSP​

Development Workflow​

Setup Watch Mode​

Advanced Configuration​

Custom RBS Paths​

Formatter Settings​

Diagnostics Settings​

Performance Settings​

Other Editor Configurations​

Neovim​

Emacs​

Sublime Text​

Troubleshooting​

Ruby LSP Not Working​

RBS Files Not Found​

Outdated Diagnostics​

Performance Issues​

Type Information Missing​

Best Practices​

1. Keep Ruby LSP Running​

2. Use Watch Mode​

3. Commit RBS Files​

4. Configure for Performance​

5. Use Steep Integration​

Complete VS Code Setup​

Keyboard Shortcuts​

Next Steps​

What is Ruby LSP?

Installation

VS Code

Other Editors

Basic Setup for T-Ruby

Step 1: Install Ruby LSP Gem

Step 2: Compile T-Ruby Code

Step 3: Configure Ruby LSP

Step 4: Configure RBS Path

T-Ruby-Specific Configuration

Working with .trb Files

Syntax Highlighting

Workspace Settings

IDE Features with T-Ruby

Autocomplete

Go to Definition

Hover Information

Inline Diagnostics

Code Actions

Document Symbols

Integration with Steep

Install Steep

Configure Steepfile

Configure Ruby LSP to Use Steep

Workflow with Ruby LSP

Development Workflow

Setup Watch Mode

Advanced Configuration

Custom RBS Paths

Formatter Settings

Diagnostics Settings

Performance Settings

Other Editor Configurations

Neovim

Emacs

Sublime Text

Troubleshooting

Ruby LSP Not Working

RBS Files Not Found

Outdated Diagnostics

Performance Issues

Type Information Missing

Best Practices

1. Keep Ruby LSP Running

2. Use Watch Mode

3. Commit RBS Files

4. Configure for Performance

5. Use Steep Integration

Complete VS Code Setup

Keyboard Shortcuts

Next Steps