Highlight field expression in types

[guimarqu]

Hey,

I'm using zed for a while and love to write Julia code with this editor.

However, when I write something like x::Module.T, the type Module.T is not highlighted and it's annoying.

So I took the evening off to understand how tree sitter and the highlight.
Here is a suggestion for fixing a part of the bug.

You see the difference before and after with the two following screenshots.

before

after

As you can see I could not make it recursive because I could not find a way to give the @type tag priority over the @variable.member tag. The most specific match seems to take precedence.

It's far from perfect but it improves the current behavior and I guess Module.SubModule.T is enough for 80% of users.
I'm opening it as a draft PR because somebody here might have the solution.

[guimarqu]

It seems impossible to match a recursive expression tree-sitter-grammars/tree-sitter-lua#24.

[guimarqu]

I improved in covering all the cases I could think about.
To ensure my suggestion works, I make the difference between modules and types by giving the correct capture.

I also changed my theme to highlight in the following screenshots the differences between the current version and my PR :

• red for variable.member
• green for module
• blue for type

current version (main branch) :

PR :

Here are my theme overrides :

"experimental.theme_overrides": {
    "syntax": {
      "type": {
        "color": "#0000AA",
        "font_weight": 700
      },
      "variable.member": {
        "color": "#AA0000",
        "font_weight": 700
      },
      "module": {
        "color": "#00AA00",
        "font_weight": 700
      }
    }
  }

[piechologist]

Thanks for your PR! I agree that should be improved.

Would you mind making this PR upstream at tree-sitter-julia? We track their reference queries which makes it easier to update the grammar and maintain our repo. Also, this would benefit other projects like neovim that use the grammar.

Let's keep this draft open to track the progress on this issue.

[aviatesk]

In the upstream issue, it's said that the preferred solution is document highlight by language server, but given the current situation where there is no LS that performs such highlighting, I think it would be better to merge this PR?

It's quite possible that I will add such highlighting to the LS I'm currently developing in the future, but it's not a current priority.

[piechologist]

From tree-sitter/tree-sitter-julia#165 (comment):

As they're written, the queries in the zed PR will match any field access. not just modules.

That's kinda the problem. [...]

The easiest way to have something somewhat good would probably be using a #match? predicate.

I'm not sure we wouldn't break something else...

[aviatesk]

Oh, I missed that part. If there's a possibility that something could break, we shouldn't rush to merge.