[fix #3017] Annotate company completion kinds

[andreyorst]

Fix #3017

This adds icon mapping for various completion kinds, allowing company-mode users to enable icons for completion items.

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Thanks!

If you're just starting out to hack on CIDER you might find this section of its
manual extremely useful.

[bbatsov]

Can you attach some screenshot of the end result?

[andreyorst]

Can you attach some screenshot of the end result?

sure!

methods variables and macros

namespace:

defrecord:

I'm not sure how to get to other icons, I don't have the code that will trigger those :)

[expez]

Maybe use constant for this (or vice versa) so you can easily tell the difference between local and global variables in the completion list?

[bbatsov]

I was going to change most of those afterwards anyways. E.g. I don't think that macro is a misc, but rather a built-in and so on. But I think there's little point in debating this too much in this particular PR.

[andreyorst]

Like this?

I think constant may be a bit misleading, but maybe it's ok. I'll let @bbatsov decide.

[bbatsov]

There are many nuances to consider and this has to be aligned with how clojure-mode works internally as well. That's why I think we can sort it out later. Just update the changelog and for now we're good to go.

[andreyorst]

E.g. I don't think that macro is a misc

Btw I've changed this to use macro icon, but given that there's no macro icon in company mode, it will default to misc icon automatically. Originally I've used misc because I was not aware of this mechanism. Maybe we can submit an issue to company mode so they could include a macro icon? Or maybe this should be done to vscode, because the icons are from there, and this will benefit to other plugins that use NREPL, like Calva.

Also triangle square and circle kinda seem like a good icon to represent macros, as this is really puzzling :D

[dgutov]

Right. We basically mirror VS Code's type. Not to say we can't extend the list, but getting nice icons can be a problem.

Anyway, check out https://github.com/emacs-mirror/emacs/blob/6ec3cf1ccb5380acc376e89140b8d3a7fa4e471a/lisp/progmodes/elisp-mode.el#L647-L655

Since there are no "real" keywords in Lisp, reusing this kind for macros and special forms seemed like a good idea.

[dgutov]

Regarding local variables, we use the value kind (following the example of some LSP servers). Which differentiates them nicely.

[andreyorst]

Since there are no "real" keywords in Lisp, reusing this kind for macros and special forms seemed like a good idea.

Clojure actually does have real keywords, and CIDER annotates those with <k>:

Though the icon kinda suggests that this is language-level keyword, not data keyword, so maybe a different icon could be used for those.

[bbatsov]

In this context I actually meant keywords in the sense of "built-ins"/"reserved words". That's how elisp-mode and clojure-mode work. Anyways, not a big deal.

[dgutov]

@andreyorst These kind of keywords are present in Elisp as well.

But that's not what is usually called a keyword in most programming languages (in Ruby, we call them "symbols", for example). And as someone who routinely works with several languages, I like to see annotations (and icons) have more universal meanings.

[bbatsov]

Thanks!