interface examples that need to play nice together

gistfile1.txt

interface Enumerable T for E {
  fn each(E, T -> Unit) -> Unit
}
impl Enumerable T for Array T {
  fn each(array: Array T, f: T -> Unit) -> Unit { ... }
}
impl Enumerable T for I : Iterator T {
  fn each(it: I, visit: T -> Unit) = ...
}
impl Enumerable T for Iterator T {
  fn each(it: Iterator T, visit: T -> Unit) = ...
}
KeyIterator = impl Enumerable K for Map K V {
  fn each(m: Map K V, visit: K -> Unit) -> Unit { ... }
}
ValueIterator = impl Enumerable V for Map K V {
  fn each(m: Map K V, visit: V -> Unit) -> Unit { ... }
}
impl Enumerable (K,V) for Map K V
  fn each(map: Map K V, f: ( (K,V) ) -> Unit) -> Unit { ... }
}


interface Iterator T for I {
  fn has_next?(I) -> Bool
  fn next(I) -> Option T
}


interface Mappable A for M A {
  fn map(m: M A, convert: A -> B) -> M B
}
impl Mappable A for Array A {
  fn map(a: Array A, convert: A -> B) -> Array B
}
impl Mappable T for Iterator T {
  fn map(a: Iterator T, convert: T -> B) -> Array B
}
KeyMapper = impl Mappable K for Map K V {
  fn map(m: Map K V, convert: K -> K2) -> Map K2 V { ... }
}
ValueMapper = impl Mappable V for Map K V {
  fn map(m: Map K V, convert: V -> W) -> Map K W { ... }
}


iterators = Array[Iterator Int](Array(1,2,3), List(4,5,6), Range(10, 20))