[Feature Request] Extract classes from code blocks

[jamesst20]

Request

Add the ability to transform code block attributes into classes.

Exemple

\  ```rust,ignore,does_not_compile
\  {{#rustdoc_include ../listings/ch09-error-handling/listing-09-10/src/main.rs}}
\  ```

Right now only the first attributes is kept: rust.

Here I believe it's where the code attributes are being stripped.

mdbook-pandoc/src/preprocess/code.rs

Lines 15 to 46 in 29e4e36

	impl<'book> CodeBlock<'book> {
	pub fn new(kind: &'book CodeBlockKind<'_>, cfg: Option<&'book mdbook::config::Code>) -> Self {
	// MdBook supports custom attributes in code block info strings.
	// Attributes are separated by a comma, space, or tab from the language name.
	// See https://rust-lang.github.io/mdBook/format/mdbook.html#rust-code-block-attributes
	// This processes and strips out the attributes.
	let (language, mut attributes) = {
	let info_string = match kind {
	CodeBlockKind::Indented => "",
	CodeBlockKind::Fenced(info_string) => info_string,
	};
	let mut parts = info_string.split([',', ' ', '\t']).map(|part| part.trim());
	(parts.next(), parts)
	};
	match language {
	Some("rust") => Self::Rust,
	language => {
	let hidelines_override =
	attributes.find_map(|attr| attr.strip_prefix("hidelines="));
	let hidelines_prefix = hidelines_override.or_else(|| {
	// Respect [output.html.code.hidelines]
	Some(cfg?.hidelines.get(language?)?.as_str())
	});
	Self::Other {
	language,
	hidelines_prefix,
	}
	}
	}
	}
	}

If we could keep classes like does_not_compile, it would grant the ability to style those code blocks to add some visual In the Epub that it doesn't compile.

Thank you :)!

[max-heller]

See #185! This is what you'll end up with (in HTML at least, probably similar in EPUB):

<pre class="sourceCode rust compile_fail"><code class="sourceCode rust">...

[jamesst20]

@max-heller Works flawlessly!

I played a little with

[output.pandoc.profile.epub3]
output-file = "output.epub"
to = "epub3"
file-scope = true
number-sections = true
standalone = true
table-of-contents = true
toc-depth = 2
css = ["epub.css"]
metadata-file = "metadata.yaml"

[output.pandoc]
hosted-html = "https://doc.rust-lang.org/nightly/book/"

[output.pandoc.code]
show-hidden-lines = false

and I wrote a quick CSS for testing and I got pretty nice results!

css-metadata.zip

output.epub.zip

[max-heller]

That looks great! I'll release a new version later today