Yay! (It's a live leaderboard, I don't have many more ideas so others will probably catch up) #IcfpContest2025 #haskell

There's a perfectly valid instance for Generic1 ((->) a), given an instance for Generic a. Should this be included in base? Probably not. But would anything break? I don't know! #haskell

gist.github.com/sjoerdvissch...

Smallcheck fun: Let's just check the (->) profunctor instance on functions on a tiny datatype, say data Three = A | B | C.

Hmm, why is it taking so long?? Oh, there are 27 functions of type Three -> Three, and the composition test takes 5 of those, that's 27^5 :-)

Just got this one with the central force turned on!

I love it when generalizations bring out more symmetry! #haskell #categorytheory

sjoerdvisscher.github.io/proarrow/Pro...
sjoerdvisscher.github.io/proarrow/Pro...

Still loving the view from my home office window!

This is the actual code. (Note that I don't draw vSplit and vCombine)

The original proof is here: ncatlab.org/nlab/show/2-...

The first success with squares in proarrow! I managed to implement preservation of limits by right adjoints using squares. I tried it before without but got bogged down with details.

sjoerdvisscher.github.io/proarrow/Pro...

I’m finally a real 🤓 now!

You can't read "A survey of graphical languages for monoidal
categories" by Peter Selinger and then not post the impressive diagram at the end!

I never used Control.Parellel.Strategies before, but I did today with #AdventOfCode. It's just adding `withStrategy (parTraversable rseq)` and each line is solved in parallel, all pure! #haskell