Construct custom query

[xvw]

At the moment, construct is a completion hook, and in some cases accessing it via a one-off query can be useful.

[coveralls]

Pull Request Test Coverage Report for Build 4485

Details

• 31 of 44 (70.45%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.08%) to 21.844%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
ocaml-lsp-server/src/custom_requests/req_construct.ml	31	44	70.45%
<!--	Total:	31	44	70.45%	-->

Totals
Change from base Build 4483:	0.08%
Covered Lines:	5556
Relevant Lines:	25435

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💛 - Coveralls

[rgrinberg]

When you say "can be useful", do you mean you have a concrete user in mind? Perhaps a client where you are planning to use this.

[xvw]

When you say "can be useful", do you mean you have a concrete user in mind? Perhaps a client where you are planning to use this.

Using Lsp through Emacs (that does not rely to much on hover and interactivy on top of mouse) can make the usage of construct cumbersome so I'll probably rely on a custom request to use it when I'll move to emacs + lsp (instead of emacs + merlin).

[rgrinberg]

I don't doubt the potential. What I'm saying is that until some client actually demonstrates real intention in using your custom request, you're just adding dead code. In the lsp standard itself, there's a requirement to demonstrate at least one client implementation for every additional protocol extension. We don't have to go that far, but how about we at least get some feedback from at least one actual client developer that is going to use this custom request before jump the gun.

[xvw]

@rgrinberg We expect different clients to use that query:

• The Jane Street internal Emacs and Vim clients (which are not open-source). At JS, they've already enhanced the contruct query by having one code action per construct value as the current design of construct in OCaml LSP is VSCode-specifiv and can't be used by Emacs and Vim. The design of one code action per construct value isn't fully satisfying either, particularly on a long list of construct values (That's why Jane Street prefers to have a custom query).
• We don't have concrete plans with a timeline yet, but we're certainly planning to have open-source Emacs and Vim extensions for the Emacs and Vim LSP plug-ins to support OCaml LSP specific functionalities. We're planning to use the new construct query in there as well.

[rgrinberg]

Okay, so what I'm getting is that the only client developer we need to consider is from JS. So let's have somebody from there have a look at this request to do a sanity check.

[rgrinberg]

cc @awilliambauer