From “reactive extensions”, a name for a family of libraries[1] (RxJava, Rx.NET, RxJS), AFAIK one of the first attempted implementations of mature FRP ideas in the imperative world and one messy enough that it took React’s success for anything similar to reënter the mainstream.

Compare the enthusiastic HN reception of “Deprecating the observer pattern” in 2011[2], mostly by people who heard of FRP in the functional-language setting, and the vitriol it received in 2018[3], apparently from people for whom FRP came to mean Rx (and similarly confused things like Bacon.js). It is this vitriol that I meant to preemptively redirect by the mention of FRP ≠ Rx, so if you’re not aware of this history it’s no big loss to ignore it.

(Yes, I am very much No-True-Scotsmanning this. That should not be taken to mean that reconciling FRP with side effects is a trivial problem, though,—I’m not sure it’s even a solved one. Only that Rx and its ilk suck as a solution.)

> My background is much more in the systems (and indeed, "signals" in the theoretical sense).

> I still think the name "signal" here is quite bad, since it's the abstract concept of something-that-carries-information

I think the intention was to allude to physical wires and conceptual analog or digital things they transmit, as in “reset signal”, “differential signalling”, etc. It does seem to me to be an apt term for a (continuous-)time-dependent doodad in a program, given “variable” is taken.

Your description sounds more like the information-theoretic “channel” or “transmission medium”.

[1] https://reactivex.io/

[2] https://news.ycombinator.com/item?id=2972581

[3] https://news.ycombinator.com/item?id=17845341