Feature Proposal: Integrate ocamlformat and ocaml-lsp-server into Opam Environments

[TheRealOwenRees]

To improve the developer experience and streamline the code review process, I propose adding ocamlformat and ocaml-lsp-server to the default opam installation for both the student switch and the Exercism development switch environments.

Standardizing the toolchain at the environment level ensures that students have a modern IDE experience out of the box and reduces friction during the submission process.

Proposed Changes

1. Toolchain Expansion

Include the following packages in the environment setup scripts/documentation:

• ocaml-lsp-server: Provides advanced IDE features like autocompletion, type-checking on hover, and real-time error highlighting. This works in conjunction with the Official OCaml VS Code Extension.
• ocamlformat: Automates code formatting based on a defined configuration.

2. Configuration & Automation

• .ocamlformat file: Add a default configuration file to the repository root. This allows the OCaml platform to automatically format code on save.

• Makefile Integration: Add a convenience command to the Makefile to support CLI-based formatting for users who prefer the terminal or use different editors:

  fmt: opam exec -- dune fmt
  

3. Why?

• Streamlined Code Reviews: Standardizing code style removes the need for mentors to comment on formatting, allowing them to focus on logic and idiomatic OCaml.

• Reduced CI/CD Overhead: Automated formatting prevents "style-only" build failures, reducing the number of resubmissions and saving CI/CD runner resources.

• Improved Onboarding: New students benefit immediately from functional linting and highlighting, which significantly lowers the barrier to entry for the language.

References

OCaml Documentation: Formatting Your Code
Dune Documentation: Formatting

[kahgoh]

Hey @TheRealOwenRees, sorry its taken me a while to get to this one. It seems that there are two audiences being considered here - students doing the OCaml track and contributors looking to work on the OCaml track.

I agree adding mention of ocaml-lsp-server would be useful for both students and contributors since it adds useful IDE features. Actually, this is already mentioned at the bottom of INSTALLATION.md, which appears on the OCaml Installation page on Exercism.

For ocamlformat, I agree it is useful for contributors so that contributions can have consistent formatting. Happy for it to be added to the root Makefile!

But I'm not so sure for students - the formatter won't be available if they use the online editor and students still could miss the formatter. I suppose we could still make them available, so students downloading to work on the exercise at least have the option, but I think mentors may still need to comment about formatting from time to time.

[TheRealOwenRees]

You have a good point regarding the students. In fact, perhaps it is best that the question of formatting comes up?

Perhaps I can integrate it into the development environment for now then? I expect some huge diffs to come your way with some of the indentation of files such as special_cases.ml. If that does happen I will will not commit those.