LSP Integration

Fresh has native support for the Language Server Protocol (LSP), providing features like:

• Real-time diagnostics: See errors and warnings in your code as you type.
• Code completion: Get intelligent code completion suggestions.
• Go-to-definition: Quickly jump to the definition of a symbol.

Configuring LSP for a New Language

To add LSP support for a language, you need to configure two sections in your ~/.config/fresh/config.json:

1. languages: Define the file extensions for the language
2. lsp: Configure the language server command

For example, to add C# support:

{
  "languages": {
    "csharp": {
      "extensions": ["cs"],
      "grammar": "c_sharp",
      "comment_prefix": "//",
      "auto_indent": true
    }
  },
  "lsp": {
    "csharp": {
      "command": "/path/to/csharp-language-server",
      "args": [],
      "enabled": true
    }
  }
}

The language name (e.g., "csharp") must match in both sections. Fresh includes built-in language definitions for Rust, JavaScript, TypeScript, and Python, but you can add any language by configuring it in your config file.

Configuring Language Detection via Settings UI

You can also configure language detection using the Settings UI instead of editing config.json directly:

1. Open Settings: Press Ctrl+, or use the command palette (Ctrl+P) and search for "Settings"
2. Navigate to Languages: Go to the Languages section
3. Add or Edit a Language: Click on an existing language to edit it, or add a new one
4. Configure Detection: Set the following fields:
   • Extensions: File extensions that should use this language (e.g., cs for C#, rs for Rust)
   • Filenames: Specific filenames without extensions (e.g., Makefile, .bashrc, .zshrc)
   • Grammar: The syntax highlighting grammar to use (must match a grammar name from syntect)

Example: Adding Shell Script Detection for Dotfiles

To make Fresh recognize .bashrc, .zshrc, and similar files as shell scripts:

1. Open Settings (Ctrl+,)
2. Go to Languages → bash (or create a new bash entry)
3. Add filenames: .bashrc, .zshrc, .bash_profile, .profile
4. The grammar should be set to Bourne Again Shell (bash) or similar

Fresh checks filenames first, then extensions, allowing dotfiles without traditional extensions to get proper syntax highlighting.