In Stanford Scala course I\'ve come across the following assignment:
Exercise 1 – Sets as Functions:
In this exercise we will represent sets
Here is another version of it using contains function:
def union(s: Set, t: Set): Set = x => contains(s,x) || contains(t,x)
def intersect(s: Set, t: Set): Set = x => contains(s,x) && contains(t,x)
def diff(s: Set, t: Set): Set = x => contains(s,x) && !contains(t,x)
def filter(s: Set, p: Int => Boolean): Set = x => contains(s, x) && p(x)