Installation Instructions Unclear

[eiiot]

Hey, thanks for this library.

I'm a bit confused as to how I can actually go about enabling the "comment" language in Zed? When I install the plugin, comment highlighting isn't enabled by default, and while the README specifies that I should modify "the injections.scm file" it's not clear where that file might be located. As I understand it, that instruction could mean one of the following:

1. make a change to a (non-existant) injections.scm file within the comment plugin directory
2. make a change to / add an injections.scm file to every language plugin I want to enable comments for
3. add an injections.scm file somewhere in each repo I want to use this plugin in
4. add / modify an injections.scm file somewhere else within the zed config

Any help here would be appreciated. I'm happy to submit a PR to update the README, but as of now I can't even figure out how to get the plugin working.

[DahTach]

It's actually the second one from my understanding.
I managed to get it working for some languages adding the injections.scm in Zed/extensions/installed/<language-name>/languages/<language-name>/injections.scm but I'm still trying to figure out how to add it to the languages that are not present in the extensions/installed/ directory like python and typescript

[llctrautmann]

@DahTach I am wondering how to do that as well..

[claytonrcarter]

languages that are not present in the extensions/installed/ directory like python and typescript

These will probably need to be updated in the extensions themselves, via PR or locally and then installing from local.

These are easy changes to make, so long as you know what the tree-sitter grammar for the given language calls it's comment nodes. (eg in Rust they're line_comment but in PHP they're comment, which is also the case in JS/TS, I think)

Also, it's worth noting that snippet in the README is not correct. I had to use @injection.content instead of @content, in other words, this worked for me in PHP:

((comment) @injection.content
 (#set! injection.language "comment"))

[thedadams]

Thanks everyone for the interest here. As pointed out, the snippet needs to be added to the injections.scm file for every language. Support was added for Rust via zed-industries/zed#39714. I will make the README more clear.

Secondly, the snippet does vary depending on the language and what is already in the injections.scm file, if anything. As @claytonrcarter pointed out, some need @injections.content and some need @content (like the Dockerfile support zed-extensions/dockerfile#25). The issue is that in a single injections.scm file, you can use only one of @injections.content or @content and never both. I will also add clarification on this.

Thanks for you interest and keep the issues rolling in for anything that doesn't work as expected!

EDIT: Sorry I missed this. I will be better about monitoring issues and PRs in the future.

[claytonrcarter]

me need @injections.content and some need @content (like the Dockerfile support zed-extensions/dockerfile#25)

FYI in the linked PR, the Dockerfile injections are using @injections.content, and also the Zed docs only mention @injections.content, not @content. Maybe @content is supported for older extensions or older versions of Zed?

The issue is that in a single injections.scm file, you can use only one of @injections.content or @content and never both

Can you clarify this? In the PHP extension, I'm using the following injections and they appear to be working fine together:

((comment) @injection.content
  (#match? @injection.content "^/\\*\\*[^*]")
  (#set! injection.language "phpdoc"))

((comment) @injection.content
 (#set! injection.language "comment"))

I don't doubt that there limitations to be aware of, but I'm curious where you found this info and/or how you found it out. Thank you!

[thedadams]

@claytonrcarter Thanks for your questions! The dockerfile PR was wrong and I needed to fix it. I just uncommented what was there, but it didn't work! I have updated the PR with the correct change.

If you were to make the bad change for the dockerfile extension locally (using @injection.content) and tried to view a dockerfile, then syntax highlighting would be completely broken.

So if the injections.scm file looked like:

((comment) @injection.content
 (#set! injection.language "comment"))

((shell_command) @content
 (#set! "language" "bash"))

and you loaded a dockerfile, then you would see an error that looks like this (using zed: open log):

2025-10-10T07:36:57-04:00 ERROR [language::language_registry] failed to load language Dockerfile:
Error loading injection query

Caused by:
    both content and injection.content captures are present

Changing the injections.scm file to

((comment) @content
 (#set! injection.language "comment"))

((shell_command) @content
 (#set! "language" "bash"))

OR

((comment) @injection.content
 (#set! injection.language "comment"))

((shell_command) @injection.content
 (#set! "language" "bash"))

will make it work.

The reason yours works is because both are using @injection.content.

Because this is all using tresitter under the hood, there is a lot that works in Zed that isn't documented. For example, I would love to use comment.info, comment.warning, etc for syntax highlighting for this plugin. If you create a theme with those nodes in the syntax section and change this extension to use those syntax names, then everything works in Zed. It's just not documented.

[claytonrcarter]

Thank you for the thorough explanation!

[thedadams]

The linked PR has been merged after feedback and suggestions from you all (which I greatly appreciate!). Closing.