module underscore

    open prelude
    open prelude.list

    array_prototype = do! `Array.prototype.forEach`

    each:
    -- The cornerstone, an **each** implementation.
    -- Handles objects implementing **forEach**, arrays, and raw objects.

           a -> (b -> c) -> d   -> e
      each(obj, iterator,   context) =

          var fe = array_prototype.forEach
          do! \ when object? fe && do! `obj.forEach === fe` =
                    obj.forEach iterator
              | when number? obj.length =
                    var f i = yield iterator.call context (get obj i) i obj
                    for [0 .. obj.length] \i = f i
              | = iterator.call