I read a recent Functional Pearl by Hinze and this inspired me to write up an example of projective programming and its motivation in logic/model theory.
This post was inspired by a curious
uncurry more common in Haskell code?
Though it does not often get mentioned in the Haskell community, simply
bumping to a new version of GHC can drastically improve the performance of your
code. Here, I have several examples from my
package, which will hopefully give an idea of just how much work has gone into
optimizing code produced by GHC.
Below, I have collected several examples of "uncanny" Haskell. These are things that may be surprising to those who have learned the language merely by doing.
You may have seen my post on co-(Elgot algebras),
in which I mentioned I had been using some exotic recursion schemes for my
gmpint package. I came across a similar example, this time for Mendler-style
recursion schemes. To my knowledge, it is the only published example of
a Mendler-style catamorphism.