racket-langserver

racket-langserver is a Language Server Protocol implementation for Racket. This project seeks to use DrRacket's public APIs to provide functionality that mimics DrRacket's code tools as closely as possible.

Installation and usage

A Racket runtime is a prerequisite, so before using racket-langserver, ensure that a Racket runtime is installed. You can install an from the official download page or install one from your package manager.

Atom

You can use the atom-ide-racket package. The language server will be automatically installed when atom-ide-racket installs.

VSCode

Use the Magic Racket extension.

Other editors and IDEs

First, install an LSP runtime for your editor.

Next, install the package via raco:

raco pkg install racket-langserver

Once it is installed, you can configure your editor to use a custom LSP client for Racket files (.rkt), and set the command for the custom client to

racket -l racket-langserver

You may need to restart your LSP runtime or your editor for racket-langserver to start.

Capabilities

Currently Supported:

• Hover (textDocument/hover)
• Jump to Definition (textDocument/definition)
• Find References (textDocument/references)
  • Note: Currently only considers references within the current file.
• Document Highlight (textDocument/documentHighlight)
• Diagnostics (textDocument/publishDiagnostics)
• Code Formatting (textDocument/formatting & textDocument/rangeFormatting & textDocument/onTypeFormatting)
• Code Action (textDocument/codeAction)
• Signature Help (textDocument/signatureHelp)
• Rename (textDocument/rename & textDocument/prepareRename)
  • Note: Currently only allows renaming symbols defined within the current file.
• Code completion (textDocument/completion)

Work in Progress:

• Document Outline (textDocument/documentSymbol)

Notes for Contributers

It is useful to think of this project as a "headless mode" for DrRacket. Contributions to this project should seek to avoid re-implementing functionality that is already exposed through DrRacket's public API.

Currently, we do not support workspace-wide (or project-wide) methods because the underlying DrRacket code tools only operate on one file at a time. If multi-file code tools are a desirable feature, then they should be considered for inclusion into DrRacket proper before being implemented in this project.

jeapostrophe commented on Apr 29, 2020

I think that the right way to implement most features in Racket-LSP is to find the corresponding feature in DrRacket and then disentangle from DrR's GUI and then expose the feature through the LSP. In many cases, DrR has already been internally organized to do that, but we just haven't done enough spelunking yet.