Dot completion for pipeable functions

[nojaf]

Hello,

I recently discovered an IDE improvement in ReScript that I think would be interesting to implement in Gleam as well.

Coming from different languages like JavaScript, users are accustomed to typing . and expecting numerous autocompletion options.

For example, with strings:

In Gleam, I see:

While I understand that the language operates differently, it would be beneficial if all functions that accept a string as their first argument could be autocompleted as well, especially in combination with a pipe.

This way, typing . would also complete |> string.length, |> string.trim, and so on.

This change would be very intuitive for beginners who may not know exactly where the helper functions are located.

Of course, I have no idea how challenging this would be to implement. I just wanted to share my thoughts!

[lpil]

Hello!

We will never use . to display functions relating to a value. Gleam is not an OOP language, and what you have written is a syntax error. To make a OOP style syntax error part of the way Gleam code is written would be very confusing.

It may be that LSP support using |> as a trigger, at which point we could prioritise functions that accept that type as one of the arguments. I believe they may even be an issue for this in the tracker, though I couldn't find it now.

[nojaf]

Hi there, thanks for your feedback!

That sounds reasonable. It would be great if |> could act as a trigger one day.

Out of curiosity, if you have something like expr |>, this is invalid code, of course, but does Gleam know what type expr has? Can the parser recover well enough so that the type is constructed? And is it able to determine the type of any expression?

[giacomocavalieri]

Hello!

Out of curiosity, if you have something like expr |>, this is invalid code, of course, but does Gleam know what type expr has?

So with a recent change the compiler is fault tolerant enough to type wrong pipes, the only missing bit is making the completions' engine aware of this and take advantage of this

[nojaf]

Wow, that's impressive! Is there any literature or talks discussing how Gleam was designed with the IDE/LSP in mind? I'm interested in learning more about the language design in relation to this.

[giacomocavalieri]

I'm afraid not 😅 I often work on the compiler live on twitch, that might be interesting if that's your cup of tea!!