Syntax-Highlighting to HTML should give a span with css class typ-error for errors

[nerdachse]

Description

Hey there!

I am experimenting with leptos and typst and in the middle of writing a simple code editor.

Now I wanted to have syntax-highlighting and fair enough, that's trivial...

fn highlight_code(code: &str) -> String {
    use typst_syntax::highlight_html;
    use typst_syntax::parse;

    let sn = parse(code);
    highlight_html(&sn)
}

The problem? https://github.com/typst/typst/blob/main/crates/typst-syntax/src/highlight.rs#L376-L385

fn highlight_html_impl(html: &mut String, node: &LinkedNode) {
    let mut span = false;
    if let Some(tag) = highlight(node) {
        if tag != Tag::Error {
            span = true;
            html.push_str("<span class=\"");
            html.push_str(tag.css_class());
            html.push_str("\">");
        }
    }
...

An error-tag is not getting a css-span!

The most trivial fix is here: nerdachse@5749284

But of course that's probably not what you want, hence this issue, so we can find a solution that fits into everyone's plans!

Use Case

Highlighting typst to html with support for errors.

[laurmaedje]

Not sure what my thinking there was. Maybe I disabled it because I wanted to frequently highlight half-wrong things like .foo(..) in the docs and everything turned red all the time. I'll need to try what happens to the docs if the if is removed.

[nerdachse]

Anything I can help with here?