Allows you to use any hash function in Sets/Dictionaries (Swift 3.0)

AnyHashable+Custom.swift

public extension AnyHashable {
  public init(value: V, compare: @escaping (V, V) -> Bool, hash: @escaping (V) -> Int) {
    self.init(CustomHashable(value: value, compare: compare, hash: hash))
  }
}

CustomHashable.swift

public struct CustomHashable<V>: Hashable {
  public let value: V
  public let compare: (V, V) -> Bool
  public let hash: (V) -> Int

  public init(value: V, compare: @escaping (V, V) -> Bool, hash: @escaping (V) -> Int) {
    self.value = value
    self.compare = compare
    self.hash = hash
  }
  
  public static func with(compare: @escaping (V, V) -> Bool, hash: @escaping (V) -> Int) -> (V) -> CustomHashable<V> {
    return {
      CustomHashable(value: $0, compare: compare, hash: hash)
    }
  }

  public static func == (lhs: CustomHashable, rhs: CustomHashable) -> Bool {
    return lhs.compare(lhs.value, rhs.value) && rhs.compare(lhs.value, rhs.value)
  }

  public var hashValue: Int {
    return hash(value)
  }
}