Edward Kmett - Propagators - Boston Haskell

Edward Kmett on Propagators at Boston Haskell

…a slightly modified environment. * http://www.macs.hw.ac.uk/ultra/skalpel Type error slicing can take advantage of that ability to do incremental computation to shrink errors and blame source locations that actually contribute. This isn't a necessary component so much as something that comes along almost for free when you put the rest together. * link to this video Propagators and LVars can be used to unify some of the stories above. Notably we can modify the story from Lindsey Kuper's work on LVars to make it so that her Par monad becomes the revision control monad mentioned in the concurrent revisions link. Then we can view LVars as side-channels for communication, and unification as giving a nice l…

I have a couple of talks on the CRDT front about propagators: link to this video link to this video The former is far more accessible, but "obvious." The latter dives down into a ton of Haskell tricks and is more of a stream of consciousness.

/u/ekmett gave a talk at Boston Haskell a few months ago (link to this video about a library he is/was working on in this space (https://github.com/ekmett/propagators). I'm not sure if it's applicable though, because as I understand it it doesn't support values that change, only values that become more defined.

I was referring to the propagator FRP story in the "Art of the Propagator" paper. It uses the purely local equational theory described in the beginning of the paper to run equations forwards and backwards, but things like `\x -> x + x` break the ability to run backwards. I talked about this issue here, but I admit it is a bit of a needle in a haystack: link to this video

I sort of want the propagator code to be as fast as humanly possible. In the Boston Haskell talk I go into a lot of the nitty gritty of what has to happen to make them really fast. link to this video I think anything architected on machines is going to pay far too much for it to be remotely competitive, and machines doesn't really address the whole pub/sub nature of listening to a lvar/cell.