Does anyone know of any systems that let you take the output value on a repl, edit it, and then edit the code so that your edit is true?

Prolog can create data structures that will make an assertion you provide be true. Within a sufficiently limited world, it might be possible to make those data structures be code of some sort.

oh interesting! I've played with prolog a little, maybe i'll look further down that data

It’s not clear to me whether “edit the code so that your edit is true” refers to a human editing the code (like a programmer trying to make a unit test pass) or a computer system editing the code automatically. If you’re going for the latter, you might be interested in “output-directed programming” / “bidirectional programming”, as exemplified by https://ravichugh.github.io/sketch-n-sketch/.

it's the latter, and thank you!

Not sure if this is what you’re asking for... Barliman (Byrd, Rosenblatt) inputs “test results” and tries to infer code that produces those same results. “miniKanren” is a newer Relational Language, kinda like Prolog in intent, except different. https://github.com/webyrd/Barliman . I find the youtube to be impressive (Clojure/conj). hth?

Oo yeah, that does seem helpful.

If you want something less text-centric, @Toby Schachman's Apparatus might be of interest. (I'm pretty wildly re-interpreting your inquiry, though, so it might not be of interest. Talking about the output of a REPL implies either a non-live or only slightly live programming environment. Apparatus is an extremely live environment.)

Yeah, aparatus feels more like the code is the output in a sense?

Yes, in a sense. Though there is still a distinction between the stuff on the canvas and the stuff in the sidebar. Sidebar stuff is abstracted away from canvas stuff in a similar way that source text is abstracted away from program output.

sidebar sidebar: I keep forgetting this wonderfulness exists (apparatus) and I'm thankful every time it reemerges in my view!

I am probably misunderstanding something, in which case, feel free to relegate me to the depths from whence I came, but, would an image based system support what you are after @Arcade Wise? Or maybe a simpler thing, like a block-based system, e.g. UF for uxn?

Hm, what do you mean?

Not exactly what you are looking for. But you might enjoy

@Jimmy Miller FYI - the code for this is now apparently online.

oh yeah! I found the barliman paper and code, it's marked as to-be-read in my zotero folder for this :>

This might be of interest: https://libfive.com/studio/