compose.py

def compose(*functions):
    return reduce(lambda x, y: lambda z: x(y(z)), functions)

def issubset(x):
    return lambda y: set(x).issubset(y)

def isdisjoint(x):
    return lambda y: set(x).isdisjoint(y)

def require(have, need, compare=issubset):
    """Returns false when requirements aren't met."""

    return compare(have)(need)

def negate(x):
    return not x

print "Should pass:"
print require([1, 2, 3], [1, 2, 3, 4])
print "Should fail:"
print require([1, 2, 3], [1, 2])
print "composed should pass:"
print require([1, 2, 3], [1, 2, 3, 4], compare=lambda x: compose(negate, isdisjoint(x)))

DirectTranslation.hs

{-# LANGUAGE OverloadedLists #-}
module Main where
import Data.Set
import Prelude hiding (null)

isDisjoint x = not . null . intersection x

require' xs ys cmp = cmp xs ys

require xs ys = require' xs ys isSubsetOf

main = do
  print "Should pass:"
  print $ require [1, 2, 3] [1, 2, 3, 4]
  print "Should fail:"
  print $ require [1, 2, 3] [1, 2, 3]
  print "Composed should pass:"
  print $ require' [1, 2, 3] [1, 2, 3, 4] $ \x -> not . isDisjoint x

Idiomatic.hs

{-# LANGUAGE OverloadedLists #-}
module Main where
import Data.Set
import Prelude hiding (null)

atLeastOne x = null . intersection x

isDisjoint x = not . atLeastOne x

requireWith cmp = cmp 

require = requireWith isSubsetOf

main = do
  print "Should pass:"
  print $ require [1, 2, 3] [1, 2, 3, 4]
  print "Should fail:"
  print $ require [1, 2, 3] [1, 2, 3]
  print "Composed should pass:"
  print $ requireWith atLeastOne [1, 2, 3] [1, 2, 3, 4]