@mgmeyers sorry for the delay - needed to check whether I was able to share the code - and because of the holidays it took a while to get the all clear.
Below is our python indentation guides extension.
We only show the second level indentation or greater (easily changed to show the first one).
We also don’t do any highlighting of the current indentation guide (like vs code might - though that might not be too difficult to add).
I’m inquiring about indentation guides on behalf of Project Jupyter. Right now, there are no indentation lines in JupyterLab, so any basic functionality would be an improvement here. The team is in the middle of upgrading to CodeMirror v6.
Taking a look at the official list of CodeMirror extensions and the indent service, I do not see indentation guides explicitly called out:
The library does not come with a built-in indentation guides extension (mostly because I find them an exceedingly pointless feature), but it should be possible to build them as an extension (view plugin that adds the appropriate 1px border, -1px margin widgets after whitespace at the start of each viewport line), so I do hope someone publishes a package for this at some point.