Unexpected output of myst_parser.main.to_html

[pohlt]

Let's say I have a very simple md file:

```{note}
Hello World
``\` <= without the backslash here, but I don't know how to write it in a code environment

If I use myst-docutils-html5 to convert this, the output is

...
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>Hello World</p>
</div>
...

I would like to convert it to a simple HTML file (w/o any wrapping or CSS), so I tried myst_parser.main.to_html. The (for me unexpected) output is this:

<pre><code class="language-{note}">Hello World
</code></pre>

Is it a different default configuration or why is it that to_html behaves so differently?

[john-hen]

That's not unexpected. The documentation says that to_html

parses markdown and renders as HTML using only the markdown-it parser (i.e. no sphinx or docutils specific processing is done)

So with to_html you just get the output of the basic Markdown-it-py parser, which follows the CommonMark specification. For this particular case, the spec says:

An info string can be provided after the opening code fence. Although this spec doesn’t mandate any particular treatment of the info string, the first word is typically used to specify the language of the code block. In HTML output, the language is normally indicated by adding a class to the code element consisting of language- followed by the language name.

This is why you get class="language-{note}" in the output.

With the Docutils-specific processing, which is what myst-docutils-html5 naturally does, the curly braces around the "language" are a cue to transform that code fence into the corresponding Doctuils directive, rather than using it for syntax highlighting.

PS: You can use four back-ticks to escape code fences of three back-ticks. That is, this

````markdown
```{note}
Hello World
```
````

is rendered as this

```{note}
Hello World
```

[pohlt]

Thanks for the quick explanation and the hint (I tried all combinations with backslashes to no avail).