package coq-lsp

Coq LSP

The coq-lsp project aims to provide a lightweight, pure Language Server Protocol server implementation for the Coq proof assistant, as well as to serve as a framework for interface experimentation.

Warning: This project is at a early stage, and it has known bugs, see the issue tracker for more information. Use at your own risk. See install information for install instructions.

Moreover, we expect the code to evolve significantly, contributions are very welcome, but please first coordinate with the dev team before writing any code.

Development Channel

Our development channel can be found at Coq's Zulip, don't hesitate to stop by.

Features

Incremental compilation and continuous document checking:

Edit your file, and coq-lsp will try to re-check only what is necessary, continuously. No more dreaded Ctrl-C Ctrl-N! Rechecking tries to be smart, and will ignore whitespace changes.

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In a future release, coq-lsp will save its document cache to disk so you can restart your proof session where you left it at the last time.

Incremental support is undergoing refinement, if coq-lsp rechecks when it should not, please file a bug!

Smart, Cache-aware Error recovery

coq-lsp won't stop checking on errors, but support (and encourages) working with proof documents that are only partially working. Moreover, error recovery integrates with the incremental cache, and will recognize proof structure.

You can edit without fear inside a Proof. ... Qed., the rest of the document won't be rechecked, unless the proof is completed.

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Whole-Document Goal Display

Press Alt+Enter (or Cmd+Enter in Mac) to show goals at point in a side panel.

Markdown support

Open a markdown file with a .mv extension, coq-lsp will check the code parts! coq-lsp places human friendly documents at the core of its design ideas.

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Document outline:

coq-lsp supports document outline, allowing you to jump directly to definitions in the document.

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Detailed timing and memory stats

Hover over any Coq sentence, coq-lsp will display detailed memory and timing statistics.

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Client-side configuration options

coq-lsp is configurable, and tries to adapt to your own workflow. What to do when a proof doesn't check, admit or ignore? You decide!

See the coq-lsp extension configuration in VSCode for options available.

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Reusability, standards, modularity

The incremental document checking library of coq-lsp has been designed to be reusable by other projects written in OCaml and with needs for document validation UI, as well as by other Coq projects such as jsCoq.

Moreover, we are strongly based on standards, aiming for the least possible extensions.

A Platform for Research !

A key coq-lsp goal is to serve as central platform for researchers in Human-Computer-Interaction, Machine Learning, and Software Engineering willing to interact with Coq.

Ẁith this goal, coq-lsp extends and will eventually replace coq-serapi, which has been used by many to that purpose.

Planned features

Jump to definition

In progress, pending on https://github.com/coq/coq/pull/16261

Proof skipping

Configure which proofs to skip or delay, to make your document workflow more reactive.

Contextual continuous checking

Check only what is visible, à la Isabelle.

Server-side Completion Help

"Semantic" goal and document printing

LaTeX document support

Workspace Integration

Don't worry about ever having to build your project again, coq-lsp will detect your workspace and build setup, and will keep everything up to date automatically.

Responsible elaboration and refinement

Supporting inlays and Lean-style infoview.

"Computational", Jupyter-style Documents

Suggestions / Search panel

Installation

Requirements

Server: opam

TODO

Server: Building from sources

To build the server, you'll need and environment with the dependencies stated in coq-lsp.opam. Opam users can do opam install --deps-only ..

Once you have done that, do make, and the server will be build under _build/install/default/bin/

Server: Nix development support

There is a Nix flake available which will setup the necessery environment and can be used via nix develop. You can then run make as usual.

Editor support and Client

Visual Studio Code: Marketplace

TODO

Visual Studio Code: Building from Sources

Assuming the server is built, install the extension as follows:

1. Symlink the editor/code directory into ~/.vscode/extensions/.

   ln -s ~/path/to/coq-lsp/editor/code ~/.vscode

   (link source should be absolute or else it won't work!)

2. Run npm install && npm run compile in editor/code.

   (cd editor/code && npm i && npm run compile)

Now you can launch VS Code through dune: dune exec -- code -n , this will setup the right environment variables such as PATH and OCAMLPATH.

Alternatively, you can just install the server and run code.

Emacs

You can use this mode with eglot with $path_to_server --std. Note that --std is needed otherwise eglot will choke due to extra messages.

Roadmap

For now the main focus of the project to write clean and maintainable code, and to provide a smooth user experience.

A core goal at this stage is to provide feedback upstream so the Coq API can be tailored to provide a good interactive experience.

For the planned first release, we hope to provide a reasonable implementation of core LSP features, editor support in VS Code.

Code organization

coq-lsp consists of several components:

• coq-serapi: [vendored] improved utility functions to handle Coq AST
• coq: Utility library / abstracted Coq API. This is the main entry point for communication with Coq.
• fleche: incremental document processing backend. Exposes a generic API, but closely modelled to match LSP methods
• lsp: small generic LSP utilities, at some point to be replaced by a generic lib
• controller: LSP controller, a thin layer translating LSP transport layer to flèche surface API.

Licensing information

The license for this project is LGPL 2.1 (or GPL 3+ as stated in the LGPL 2.1).

• This server forked from our previous LSP implementation in for the Lambdapi by Emilio J. Gallego Arias, Frédéric Blanqui, Rodolphe Lepigre, and others.
• Syntax files in editor/code are partially derived from VSCoq by Christian J. Bell, distributed under the terms of the MIT license (see ./vsc-galinas/License-vscoq.text).

Team

• Ali Caglayan (co-coordinator)
• Emilio J. Gallego Arias (Inria Paris, co-coordinator)
• Shachar Itzhaky (Technion)
• Ramkumar Ramachandra

Acknowledgments

Work on this server has been made possible thanks to many discussions, inspirations, and sharing of ideas from colleagues. In particular we'd like to thank Rudi Grinberg, Andrey Mokhov, Clément Pit-Claudel, and Makarius Wenzel for their help and advice.