(\\) == deleteFirstsBy (==)The second list must be finite, but the first may be infinite.
>>> deleteFirstsBy (>) [1..10] [3, 4, 5] [4,5,6,7,8,9,10]
>>> deleteFirstsBy (/=) [1..10] [1, 3, 5] [4,5,6,7,8,9,10]
>>> deleteFirstsBy (==) (slist [1..5]) (slist [2,8,4,10,1]) Slist {sList = [3,5], sSize = Size 2}