Racket Mode users: Want to try new "multi back end" branch?

I have a branch I've been working on for 5 months, off and on, that lets Racket Mode work with multiple back ends; this arose from PR 533.

Here's an explanation of the new "architecture".

If it needs more work, I'd like to tackle that... otherwise merge it soon.

If you use Racket Mode straight from the git repo (via straight.el, borg, or otherwise) I wonder if you might try using the rebased-multi-back-end branch for a few days and let me know if you experience any problems.

(If you install Racket Mode from MELPA, I'm not asking you to muck around with this unless you really really want to. Not seeking to cause a hassle for anyone.)

An important point is that it should "do no harm" -- if you don't need any of this stuff, it should work just fine as before. So in any case I'd love to have your help, if you can.

Thank you.

p.s. I'm happy to get feedback here, or on Slack, or on the GitHub repo.


Greg, just to say the work on Racket mode is imo, some of the most important work for the racket community. Thanks for taking the time to improve this. It's very welcome!

I will move to using the rebased-multi-back-end branch and report back.


I know some of you have already tried the branch -- thank you!

I did get one bug report that was orthogonal and we already fixed that on the main branch.

Probably "no news is good news", but... if anyone wants to provide explicit feedback, could you please "vote" below?

  • :slightly_smiling_face: I used the default, single back end: Nothing seemed to break.
  • :smiley_cat::smiley_cat: I tried multiple back ends: Worked as expected.
  • :slightly_frowning_face: I had another experience; I'll comment here or open an issue on GitHub.

0 voters


I've been using it since Friday morning. No problems so far, but I haven't tried using remote backends yet.

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Thanks everyone for the feedback here and elsewhere. This is now merged. :tada:


@greghendershott Just wanted to tell you that the recent updates to Racket Mode also fixed a minor issue I have been having on Guix System since a couple of months. Racket Mode used to underline the first character of the file and show some weird index error. I don't remember the message any more. I was planning to debug the issue in the near future, but you already fixed it, thanks!

@scolobb Do you mean for example it would underline the # in #lang at the very start of the file?

This sounds similar to --- but not exactly like --- Extraneous "no bound occurrences" and `racket-xp-unused-face` · Issue #578 · greghendershott/racket-mode · GitHub which I was never able to reproduce myself.

This also sounds similar to --- but not exactly like --- something I did see myself, and did fix in December.

So you're welcome but honestly I'm not confident I fixed what you had been seeing. I definitely did make a change that rules out some space of problems. If you ever do still see it or something similar, of course please let me know here or on that GitHub issue.

Yes, exactly.

The error message I was getting was something about an index being out of bounds as far as I can remember.

Absolutely! Thank you for your work on Racket Mode, it is central to my Racket experience.

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