merlin VS ocaml-lsp

Merlin: Context sensitive completion for OCaml in Vim and Emacs\ (0 comments)

Instead of searching functions based on their type structure (like Hoogle), you could search for functions that "consume"/"produce" values of given types (like OCaml's Merlin). I think Rust already computes variance of type constructors, so such a tool just would have to obtain this information.

However, after posting this question I stumbled upon this Github issue where they say it isn't supposed to work out of the box and you're supposed to bind a key to it by editing your .emacs file. Turns out the default .emacs file binds auto-complete to "backtab" which means Shift+Tab but that didn't work. I did eventually discover that I can get some kind of completion by binding backtab to completion-at-point like this:

Self-advertising: I partcipated to the writing of Merlin: A Language Server for OCaml (Experience Report), which explains the overall design of Merlin, a language server for OCaml. A key idea of Merlin are that classic lexing-parsing-typing pipelines can easily be adapted to be incremental for a Language Server, especially when they are using immutable data structures.

> There is no alternative to Django, for instance.

https://aantron.github.io/dream/, which is new and used by ocaml.org

> No serious IDE, except emacs

and vim, and visual studio, and whatever else supports the LSP protocol via https://github.com/ocaml/ocaml-lsp

> The standard library was so lacking that there is at least an alternative.

While janestreet does have an publish their own stdlib, I personally try to stick to the stdlib whenever possible. Not to knock janestreet. I'm glad they're around and have contributed a bunch.

But overall I agree with you. It's been my favorite language two write in for years now. You can't just reach for off-the-shelf libraries for every little thing. Although the ones that do exist tend to be written halfway decently.

Merlin is great, but it's vim plugin leaves a bit to be desired (in particular, it doesn't seem to use any of the modern async apis from vim 8+/neovim). Personally ocaml-lsp (which is still backed by Merlin on the backend) together with neovim's built-in lsp support has been far smoother for me

Perhaps the README[1] is out of date, but it appears to note that textDocument/implementation is not done? That's a pretty big hole.

[1]: https://github.com/ocaml/ocaml-lsp/#features

Short answer: yesWith https://marketplace.visualstudio.com/items?itemName=ocamllabs.ocaml-platformand https://github.com/ocaml/ocaml-lspand https://dune.readthedocs.io/en/stable/and utop

This is the one I tried and seems well supported - https://github.com/ocaml/ocaml-lsp . I've only started very lightly playing around with ocaml. It seems to be working fine on vscode and seems to do as expected on nvim too, at least as far as I configured nvim for it.

Typically I would recommend using https://github.com/ocaml/ocaml-lsp which is now the main OCaml language server, and VSCode with the OCaml Platform extension, a combo I know works well.

You might also look into ocaml-lsp for inspiration. Not everything will carry over to SML but it might help somtimes.