merlin-language-server

Simple LSP protocol wrapper for merlin, written in reason

:warning: Alpha quality

Overview

merlin-language-server is a thin wrapper over the excellent merlin tooling - implementing the LSP protocol on-top of merlin's protocol.

As with ocaml-language-server, this is not intended as a replacement for any existing Reason / OCaml tooling, but to make it more accessible across editors.

Why?

There are already two excellent language server implementations - reason-language-server and ocaml-language-server - why another one?

The current language-server landspace could be summarized with this table:

NOTE (1): I believe ocaml-language-server may support Windows, but I was not able to get it working.

NOTE (2): reason-language-server mentions Windows support as a goal, but again, it did not work for me. I contributed several fixes towards this (PRs #36, #130, #199), but there is still significant investment required to get support on parity with merlin on Windows.

The primary issue for me being that there was not a language server implementation that worked well for me on Windows. It turns out that merlin works great on Windows - so having a native-reason LSP implementation that uses merlin is a natural choice.

In the future, perhaps we could integrate this more fully into merlin at some point, or incorporate merlin as a library that we call directly.

Building

Prerequisites

• You will need esy to build - npm install -g esy
• For running tests, you will need node.

Build

• git clone https://github.com/bryphe/merlin-language-server
• esy install
• esy build

Tests

• Unit tests: esy x TestRunner.exe
• E2E tests:
  • cd test-e2e
  • npm install
  • npm test

Roadmap

• Distribution
  • [ ] First-class Oni integration
  • [ ] VSCode Plugin
  • [ ] NPM package with pre-built binaries
• Features
  • Text synchronization
    • [x] textDocument/didOpen
    • [x] textDocument/didChange
    • [x] Full document sync
    • [ ] Incremental document sync
  • Language Features
    • [x] completion
    • [x] hover
    • [ ] definition
    • [ ] implementation
    • [ ] references
    • [ ] signatureHelp
    • [ ] codeAction?
    • [ ] codeLens
    • [ ] formatting
    • [ ] rangeFormatting
    • [ ] onTypeFormatting

Contributions

Contributions & PRs are welcome! Please ensure that test coverage is added for any new functionality - either in the form of unit tests or E2E tests.

License

MIT License

Copyright 2018 Bryan Phelps