Re: [Haskell-cafe] Faster set intersections?

One can write a function Eq a => ((a -> Bool) -> a) -> [a] that enumerates the elements of the set. Because we have universal quantification, this list can not be infinite. Which makes sense, topologically: These so-called searchable sets are topologically compact, and the Eq constraint means the space is discrete. Compact subsets of a discrete space are finite.

Olaf

Olaf (or anyone else), can you help me out here and write this function, with some example inputs and outputs?