Custom language definition for syntax highlighter

[danielvaughn]

What version of starlight are you using?

0.10.0

What is your idea?

As a user, I would like to provide my own language definition for syntax highlighting.

Why is this feature necessary?

I admit this is an edge case - I'm developing a language and would like to provide syntax highlighting for it in my code examples. It would prevent me from having to implement a component from scratch for syntax highlighting.

(side note - I love Starlight, much thanks to the team for building this amazing tool)

Do you have examples of this feature in other projects?

• No similar tool exists (to my knowledge)

Participation

• I am willing to submit a pull request for this issue.

[HiDeoo]

There is an ongoing effort to add Expressive Code to Starlight which would use astro-expressive-code to render code blocks.

I think it uses @expressive-code/plugin-shiki to perform syntax highlighting using shiki which does support adding your own language (using TextMate grammar files).

Altho, I don't know how accessible this skiki API is through Expressive Code but maybe @hippotastic may have more informations regarding that part.

[danielvaughn]

fantastic, thanks so much for the quick response!

[hippotastic]

The loadLanguage API is not accessible through plugin-shiki yet, but I can definitely add this.

Once you have a .tmLanguage file and code snippet in your language ready, please share a link to it here and we'll give it a try!

[danielvaughn]

Thank you! If it's a matter of making a change to the codebase itself, I don't mind making my own PR.

[delucis]

Thanks for the issue and discussion! Sounds like this would need to be addressed in upstream libraries rather than Starlight directly, so will close the issue here if that’s OK — we can always revisit later if it turns out there’s some work needed on our end to expose new API options to users.