I don't know how up to date it is, but the author of this article claims that the combinator-based solution is among the fastest: https://willamette.edu/~frueh

I don't know how up to date it is, but the author of this article claims that the combinator-based solution is among the fastest: https://willamette.edu/~fruehr/haskell/evolution.html?#combinatory https://willamette.edu/~fruehr/haskell/evolution.html?#combi...