Rendering issue with C++ notebooks

[bluescarni]

Describe the bug

I am using myst-nb to include in sphinx C++ notebooks written on top of cling.

The issue is that C++ pragmas beginning with # seem to be interpreted as Python comments when they are rendered in sphinx by myst-nb.

E.g., compare the original notebook in jupyter:

vs the html produced by sphinx + myst-nb:

As you can see, the second #pragma line is formatted as a comment.

Environment

sphinx and myst-nb have been installed from conda-forge. The versions are 3.5.3 and 0.12.0 respectively.

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[chrisjsewell]

thanks for the report, I guees this may be a problem with the pygments lexer: https://pygments.org/docs/lexers/#pygments.lexers.c_cpp.CppLexer

Can you provide an example notebook, i.e. I want to see what is set as the pygments lexer in the metadata:

{
  "metadata": {
    "kernelspec": {
      "display_name": "Python 3",
      "language": "python",
      "name": "python3"
    },
    "language_info": {
      "codemirror_mode": {
        "name": "ipython",
        "version": 3
      },
      "file_extension": ".py",
      "mimetype": "text/x-python",
      "name": "python",
      "nbconvert_exporter": "python",
      "pygments_lexer": "ipython3",
      "version": "3.6.1"
    }
  }
}

[bluescarni]

Hi @chrisjsewell , thanks for the quick reply.

Here is a sample notebook:

https://github.com/bluescarni/mppp/blob/master/doc/notebooks/integer_basics.ipynb

This is how it is rendered in sphinx:

https://bluescarni.github.io/mppp/notebooks/integer_basics.html

(you can launch it in binder from the rocket icon if you want)

[chrisjsewell]

Ok ta, there is no actual pygments lexer set:

 "metadata": {
  "kernelspec": {
   "display_name": "C++17",
   "language": "C++17",
   "name": "xcpp17"
  },
  "language_info": {
   "codemirror_mode": "text/x-c++src",
   "file_extension": ".cpp",
   "mimetype": "text/x-c++src",
   "name": "c++",
   "version": "17"
  }
 },

so it will default to language_info/name, i.e. c++: https://github.com/executablebooks/MyST-NB/blob/a54dc18cb90c8845123f29f261132145ef2349b2/myst_nb/parser.py#L138-L139

So my next course of action would be to create a minimal example case, directly passing some text to pygments and see if this replicates the issue. If so, then open an issue on https://github.com/pygments/pygments

I can try this when I have some time, or obviously feel free to try yourself 😄