haskell/containers — pull request #37 by kardboardb (2014-02-20 00:09:08+00:00)
Title: Add lookupWith and split(Lookup)With to Map

These functions allow a custom comparison function to be substituted for
`compare` when looking up values in and splitting maps.

The original `lookup`, `split`, and `splitLookup` functions are then
implemented as their -With counterparts curried with the `compare`
function from Prelude.