Contributing a CodeMirror mode for a new language

I have a CodeMirror mode for a language not already covered by CodeMirror (namely Maxima, I would like to have it bundled with other CodeMirror modes which are shipped with JupyterLab.

The CodeMirror project is no longer accepting PR’s to implement new language modes; instead they are asking authors to create a NPM package and publish it themselves. So that’s okay by me, however, it’s not clear to me how a new language mode would get included in JupyterLab.

I see that jlpm run build:packages seems to fetch all the CodeMirror modes which are packaged with the base distribution of CodeMirror, that’s great. How would it be arranged to fetch a CodeMirror mode implemented by a separate package – what should I ask the JupyterLab project to do? I.e., for what file should I make a PR.

I’m guessing that there must be a list of all packages fetched by jlpm and I guess I’m hoping that someone can point me in the right direction. I’m kind of hung up on the idea of a list of packages, maybe that is not the right way to think about it; if so, again, I hope someone will point me in the right direction.

All the best, and thanks for your help,

Robert Dodier

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At present, there is no “standard” way of getting CodeMirror syntax modes added to JupyterLab Core… and as that project is considering fully embracing (ne 6) which uses a different syntax highlighting system, it seems like it would be unwise for us to start taking on a potentially uncountable number of language-specific sets of code… which the upstream has also dropped.

Some alternative approaches:

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Thanks for the info. I should have mentioned that there is a kernel for Maxima (GitHub - robert-dodier/maxima-jupyter: A Maxima kernel for Jupyter, based on CL-Jupyter (Common Lisp k), in which the CodeMirror maxima.js is currently living, and it is installed by patching the CodeMirror installation by hand; I’m looking for a more automatic way to go about it, hence my question here.

You mentioned jupyter labextension build – I will take a look at this, thanks for the pointer.

But perhaps I’ve missed something. Is there a way to bundle the CodeMirror mode only with the language kernel, avoiding the need to install any files into a system installation of CodeMirror or JupyterLab or anything else? Thanks for any insights.


Robert Dodier

However the maxima package copies files on installation to…

  • $PREFIX/share/jupyter/kernels/maxima/
    • kernel.json

…it would also need, at build time to have turned…

  • package.json
  • index.js # or .ts or whatever

…into the following files, and copy them to…

  • $PREFIX/share/jupyter/labextensions/maxima-mode/ # or whatever
    • package.json # this gets copied and updated
    • static/
      • remote.entry.1234abc.js # this gets built by jupyter labextension build
      • abc1234.js # the actual code

But otherwise: there isn’t really a predictable, simpler way to provide enough information and metadata to JupyterLab or CodeMirror that .some-random-extension is of MIME type text/x-some-random-type and should use a syntax mode called Some Random Language. The jupyterlab-simple-syntax idea, discussed in the stan thread, would make that possible, but might be limited to declarative grammars (e.g. CodeMirror simplemode, nearly.js, etc.)