code-block rendering does not work as expected

[stefaneidelloth]

code-block rendering should support line numbers and highlighting.

JupyterLab Preview:

Output of similar code block with latexpdf in Sphinx:

For VsCodium preview see related issue ticket:

https://github.com/executablebooks/myst-vs-code/issues/57

(My preffered IDE would be PyCharm but it does not seem to support MyST directives.)

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[agoose77]

This feature does work, but it differs between MyST-JS and Sphinx. We should ensure that they behave the same, although Sphinx has quirks.

@rowanc1 the following code blocks look different in Sphinx and MyST-JS:

```{code-block}
:lineno-start: 10
:linenos:
:emphasize-lines: 12,13

1, 2, 3
4
5
6
7
```

```{code-block}
:lineno-start: 10
:emphasize-lines: 12,13

1, 2, 3
4
5
6
7
```

```{code-block}
:lineno-start: 10
:emphasize-lines: 2,3

1, 2, 3
4
5
6
7
```

Sphinx:

jupyterlab-myst:

It looks like Sphinx doesn't use lineno-start as a programmatic offset (only visually). Also, Sphinx uses the presence of lineno-start to activate line numbers . Do you think we can bring these into alignment?

I'm running out of cycles to do this right now, but it looks simple enough:

• This needs adjusting to lookup the line subtracted by the offset
• This needs to consider lineno-start for showLineNumbers

[rowanc1]

Ha, I remember explicitly testing that the offset worked properly and the lines we were highlighting were the same!! Happy to take that out and revert to how sphinx works here. Adding a warning about highlighting lines outside the visible region could also be good!

[agoose77]

Right - I personally think our implementation is the right one, but I know that we won't change sphinx on this 😅

[rowanc1]

I have fixed the first portion of the bug lineno-start turning on showLineNumbers in:

• https://github.com/executablebooks/mystmd/pull/610