GNU bug report logs - #75406
31.0.50; [PATCH] csharp-ts-mode does not highlight type in typeof() expressions

Previous Next

Full log

View this message in rfc822 format

From: Yuan Fu <casouri <at> gmail.com>
To: Jostein Kjønigsen <jostein <at> secure.kjonigsen.net>
Cc: Theodor Thornhill <theo <at> thornhill.no>, 75406 <at> debbugs.gnu.org
Subject: bug#75406: 31.0.50; [PATCH] csharp-ts-mode does not highlight type in typeof() expressions
Date: Tue, 7 Jan 2025 22:14:28 -0800

> On Jan 6, 2025, at 6:12 AM, Jostein Kjønigsen <jostein <at> secure.kjonigsen.net> wrote:
> 
> Hey everyone.
> 
> When using csharp-ts-mode to edit C# files, you may encounter the use of the typeof() operator in typeof()-expressions. The typeof() operater has 1 required parameter, which is always a type-name.
> 
>     public class Gnu
>     {
>         public void Demo()
>         {
>             var type = typeof(IQueryable);
>         }
>     }
> 
> This type parameter should be fontified using font-lock-type-face. Currently it is not.
> 
> There are explicit rules in csharp-ts-mode defined to attempt to fontify this, but they do not seem to be working:
> 
>      ,@(when (csharp-ts-mode--test-type-of-expression)
>          '((type_of_expression (identifier) @font-lock-type-face))
>          '((typeof_expression (identifier) @font-lock-type-face)))
> 
> Based on my inspection in treesit-explore mode, I see the grammar reports back these nodes as typeof_expression-nodes, but these rules are not activated because the preceeding (when ...) condition fails.
> 
> (defun csharp-ts-mode--test-type-of-expression ()
>   "Return non-nil if (type_of_expression) is in the grammar."
>   (ignore-errors
>     (treesit-query-compile 'c-sharp "(type_of_expression)" t)
>     t))
> 
> Changing this implementation to the following (matching the node-names I see in treesit-explore mode) makes highlighting work for me:
> 
> (defun csharp-ts-mode--test-type-of-expression ()
>   "Return non-nil if (type_of_expression) is in the grammar."
>   (ignore-errors
>     (treesit-query-compile 'c-sharp "(typeof_expression)" t)
>     t))
> 
> Attached is a patch which provides this change.
> 
> Note: This bug/fix was reproduced using tree-sitter-c-sharp grammar built on December 18th, 2024. I haven't tested with other versions.
> 
> Kind regards
> Jostein
> 
> <0001-lisp-progmodes-csharp-mode.el-Fix-fontification-of-t.patch>

Thanks! I suspect that an earlier grammar version used type_of_expression. Can you see if it’s true? If it is, we should keep the rules for both type_of_expression and typeof_expression, WDYT?

On the same note, we could use some utility function that makes it less verbose to test queries and use different query based on the test result.

Yuan

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.