ocaml-lsp 1.5.0 does not suggest keywords

[Tchou]

While working on a code base with OCaml 4.12.0 in VS Code, it occurred to me that the OCaml Platform extension was not giving keywords such as in as possible completions (which quickly gets annoying because, you don't use in_channel_length all that often ;)).

When I switched back to OCaml 4.11.2 (with opam), the same extension works as expected, and has since ocaml-lsp-server 1.2.0 (which fixed #173).

I also tried the current master with 4.12.0 and it does not work either. I wiped clean both switches (no pins) and created a simple directory with a simple .ml file to ensure that this was not caused by a local switch, forgotten pin or other.

Screenshot with OCaml 4.12.0/ocaml-lsp-server 1.5.0:

Screenshot with OCaml 4.11.2/ocaml-lsp-server 1.4.1:

[rgrinberg]

Unfortunately we had to remove this feature. It wasn't going to be upstreamed by the merlin devs in a useful form and it is kind of a pain to maintain. In addition, the merlin devs are working on a smarter alternative to keyword completion. I don't have more information about an ETA but perhaps @voodoos does.

[Tchou]

I see. That's unfortunate indeed. For reference and as a workaround in vscode, "editor.acceptSuggestionOnEnter": "off" makes for a reasonable experience (I haven't found a way to set a length threshold so that completion only kicks in after 3 chars).
The keyword in has a really bad combination of features here, which is why it would maybe warrant a special treatment :

• it's a prefix of types (int, in_channel, …) and identifiers (incr, input_*, …) from Stdlib.
• its use is pervasive in idiomatic OCaml code
• it's often at the end of a line, thus followed by an [enter] keypress (which accepts the first completion in vscode default config)

The only other keyword with these characteristics that I found is do with do_at_exit, and is used far less often. for is not problematic as it is rarely followed by a new line.

It also seems (at least from the bug tracker) that both issues are mutually dependent, since ocaml/merlin#1229 seems to mention that this is handled by a work-around in ocaml-lsp (which has now been disabled waiting for a solution in merlin).

But I have no problem with the issue being closed or marked as feature/enhancement as long as it's monitored somewhere.

[voodoos]

Looking at Merlin's PR history there was that one: ocaml/merlin#1243 by @trefis
Is it not in a "useful form" for Ocaml-LSP because of the lack of "completion by context" ?

[rgrinberg]

Yes. Suggesting all keywords in every context adds a lot of noise.

[bluddy]

This is a very annoying issue that hits me in neovim as well. I think it needs to be dealt with as it greatly hampers the experience of writing ocaml compared to other languages.

[daytoncf]

This is a very annoying issue that hits me in neovim as well. I think it needs to be dealt with as it greatly hampers the experience of writing ocaml compared to other languages.

100% agree with @bluddy here. I use VSCode and the amount of timed I get irrelevant autocomplete when using language keywords is infuriating. Never had this problem w any other language

[rgrinberg]

I agree 100% with all of you as well. But the question is, how do we proceed?

[bluddy]

I think the first priority is to special case in. in is at the end of our lines, which means it needs to be followed up by an return key. It's also extremely common. do is the next candidate but it's far less common. @Tchou already said this in more detail 2 years ago, and he's right. We need to suggest these two keywords before all other choices.

[rgrinberg]

Okay, PR's welcome!