One-line definition of the power set function
If you thought the one-line definition of the Fibonacci sequence in Haskell was beautiful, try this:
import Control.Monad powerset :: [a] -> [[a]] powerset = filterM (const [True, False])
A black box for sure, unless you have "internalized the list monad". But it does show how stonkingly powerful monads are.
[ Entry posted at: Mon 02 Jul 2007 18:45:21 BST | 0 comment(s)... | Cat: Geeky ]