coq-lsp is a Language Server and Visual Studio Code extension for the Coq Proof Assistant. Experimental support for Vim and Neovim is also available in their own projects.
Install for Visual Studio is as easy as:
$ opam install coq-lsp && code --install-extension ejgallego.coq-lspKey features of coq-lsp are continuous and incremental document checking, advanced error recovery, markdown support, positional goals and information panel, performance data, and more.
coq-lsp aims to provide a seamless, modern interactive theorem proving experience, as well as to serve as a maintainable platform for research and UI integration with other projects.
coq-lsp is built on top of Flèche, a new document checking engine for formal documents, designed from our experience in previous, projects. Flèche is specifically optimized for interactive use, SerAPI-like tooling integration, and web native usage, providing quite a few extra features from vanilla Coq.
coq-lsp supports π§ Linux, π macOS, πͺ Windows , and β JavaScript (Node/Browser)
.vo file savingEdit 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.

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!
coq-lsp won't stop checking on errors, but supports (and encourages) working with proof documents that are only partially working. Error recovery integrates with the incremental cache, and does recognize proof structure.
You can edit without fear inside a Proof. ... Qed., the rest of the document won't be rechecked; you can leave bullets and focused goals unfinished, and coq-lsp will automatically admit them for you.
If a lemma is not completed, coq-lsp will admit it automatically. No more Admitted / Qed churn!

coq-lsp will follow the cursor movement and show underlying goals and messages; as well as information about what goals you have given up, shelves, pending obligations, open bullets and their goals.

Goal display behavior is configurable in case you'd like to trigger goal display more conservatively.
Open a markdown file with a .mv extension, coq-lsp will check the code parts that are enclosed into coq language blocks! coq-lsp places human-friendly documents at the core of its design ideas.

Moreover, you can use Visual Studio Code Markdown preview to render your markdown documents nicely!
coq-lsp supports document outline and code folding, allowing you to jump directly to definitions in the document. Many of the Coq vernacular commands like Definition, Theorem, Lemma, etc. will be recognized as document symbols which you can navigate to or see the outline of.

Hovering over a Coq identifier will show its type.

Hover is also used to get debug information, which can be enabled in the preferences panel.
coq-lsp supports projects with multiple _CoqProject files, use the "Add folder to Workspace" feature of Visual Studio code or the LSP Workspace Folders extension to use this in your project.
.vo file savingcoq-lsp can save a .vo file of the current document as soon as it the checking has been completed, using the command Coq LSP: Save file to .vo.
You can configure coq-lsp in settings to do this every time you save your .vo file, but this can be costly so we ship it disabled by default.
Hover over any Coq sentence, coq-lsp will display detailed memory and timing statistics.

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.

coq-lsp includes the fcc "Flèche Coq Compiler" which allows the access to almost all the features of Flèche / coq-lsp without the need to spawn a fully-fledged LSP client.
fcc has been designed to be machine-friendly and extensible, so you can easily add your pre/post processing passes, for example to analyze or serialize parts of Coq files.
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.
coq-lsp has been designed from the ground up to fully run inside your web browser seamlessly; our sister project, jsCoq has been already been experimentally ported to coq-lsp, and future releases will use it by default.
coq-lsp provides an exciting new array of opportunities for jsCoq, lifting some limitations we inherited from Coq's lack of web native support.
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.
Towards this goal, coq-lsp extends and is in the process of replacing Coq SerAPI, which has been used by many to that purpose.
If you are a SerAPI user, please see our preliminary migrating from SerAPI document.
In order to use coq-lsp you'll need to install both coq-lsp and a suitable client. We recommend the Visual Studio Code Extension as client.
coq-lsp supports Coq 8.15, 8.16, Coq 8.17, and Coq's master branch. Code for each Coq version can be found in the corresponding branch.
We recommended a minimum of Coq 8.17, due to better test coverage for that version. For 8.16, we recommend users to install the custom Coq tree as detailed in Working With Multiple Files
Support for older Coq versions is possible; it is possible to make coq-lsp work with Coq back to Coq 8.10/8.9. If you are interested in making that happen don't hesitate to get in touch with us.
opam:
opam install coq-lspNix:
inputs.coq-lsp = { type = "git"; url = "https://github.com/ejgallego/coq-lsp.git"; submodules = true; };
...
coq-lsp.packages.${system}.defaultWindows: To install coq-lsp on windows, we recommend you use a cygwin build, such as the one described here, tho any OCaml env where Coq can be built should work.
coq-lsp from source (branch v8.16, which will become 0.1.7)coq-lsp.exe binary in VS Code settings--ocamlpath=c:\$path_to_opam\lib argument in VS Code settings if you get a findlib error. The Coq Platform ships with an un-configured binary. Note, the path should be unquoted.dll error you'll need to copy that dll (often libgmp-10.dll) to the C:\Windows folder for coq-lsp to work.Coq Platform (coming soon)
inputs.coq-lsp = { type = "git"; url = "https://github.com/ejgallego/coq-lsp.git"; submodules = true; };
...
programs.vscode = {
enable = true;
extensions = with pkgs.vscode-extensions; [
...
inputs.coq-lsp.packages.${pkgs.system}.vscode-extension
...
];
};lsp-mode has been provided by Arthur Azevedo de Amorim, supporting goal display, see the Zulip thread for more information.Experimental CoqTail support by Wolf Honore: https://github.com/whonore/Coqtail/pull/323
See it in action https://asciinema.org/a/mvzqHOHfmWB2rvwEIKFjuaRIu
coq-lsp discussion channel it at Coq's Zulip, don't hesitate to stop by; both users and developers are welcome.
We hold (almost) weekly video conference calls, see the Call Schedule Page for more information. Everyone is most welcome!
See our list of frequently-asked questions.
Coq LSP > Method to Print Coq Terms to 0 as a workaround.coq-lsp can fail to interrupt Coq in some cases, such as Qed or type class search. If that's the case, please open an issue, we have a experimental branch that solves this problem that you can try.coq-lsp/VSCode simultaneously with the VSCoq Visual Studio Code extension, Visual Studio Code gets confused and neither of them may work. coq-lsp will warn about that. You can disable the VSCoq extension as a workaround.coq-lsp, in Visual Studio Code, Ctrl+Shift+P will give you access to the coq-lsp.restart command. You can also start / stop the server from the status bar.Coq LSP > Trace: Server option.coq-lsp can't work with more than one file at the same time, due to problems with parsing state management upstream. This was fixed in Coq 8.17.
As this is very inconvenient for users in older Coq versions, we do provide a fixed Coq branch that you can install using opam pin:
For Coq 8.16:
opam pin add coq https://github.com/ejgallego/coq.git#v8.16+lspSee planned features and contribution ideas for a list of things we'd like to happen.
coq-lsp mostly implements the LSP Standard, plus some extensions specific to Coq.
Check the coq-lsp protocol documentation for more details.
Contributions are very welcome! Feel free to chat with the dev team in Zulip for any question, or just go ahead and hack.
We have a contributing guide, which includes a description of the organization of the codebase, developer workflow, and more.
Here is a list of project ideas that could be of help in case you are looking for contribution ideas, tho we are convinced that the best ideas will arise from using coq-lsp in your own Coq projects.
The license for this project is LGPL 2.1 (or GPL 3+ as stated in the LGPL 2.1).
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, ClΓ©ment Pit-Claudel, and Makarius Wenzel for their help and advice.
As noted above, the original implementation was based on the Lambdapi LSP server, thanks to all the collaborators in that project!