interface Sequence

# Sequence provides the sequence standard library API.
interface Sequence extends Iterable
  # iter provides the sequence API operation.
  # @return Iterator the resulting value.
  iter: ->
  # map provides the sequence API operation.
  # @param fn Function fn value.
  # @return Sequence the resulting value.
  map: fn ->
    MapSequence(self, fn)
  # filter provides the sequence API operation.
  # @param fn Function fn value.
  # @return Sequence the resulting value.
  filter: fn ->
    FilterSequence(self, fn)
  # take provides the sequence API operation.
  # @param n Int n value.
  # @return Sequence the resulting value.
  take: n ->
    TakeSequence(self, n)
  # drop provides the sequence API operation.
  # @param n Int n value.
  # @return Sequence the resulting value.
  drop: n ->
    DropSequence(self, n)
  # reduce provides the sequence API operation.
  # @param initial Int initial value.
  # @param fn Function fn value.
  # @return Any the resulting value.
  reduce: initial, fn ->
    acc = initial
    for item in self
      acc = fn(acc, item)
    acc
  # each provides the sequence API operation.
  # @param fn Function fn value.
  # @return Nil the resulting value.
  each: fn ->
    for item in self
      fn(item)
    nil
  # any? provides the sequence API operation.
  # @param fn Function fn value.
  # @return Boolean the resulting value.
  any?: fn ->
    for item in self
      if fn(item)
        return true
    false
  # all? provides the sequence API operation.
  # @param fn Function fn value.
  # @return Boolean the resulting value.
  all?: fn ->
    for item in self
      if not fn(item)
        return false
    true
  # find provides the sequence API operation.
  # @param fn Function fn value.
  # @return Any the resulting value.
  find: fn ->
    for item in self
      if fn(item)
        return item
    nil
  # to_a provides the sequence API operation.
  # @return Array the resulting value.
  to_a: ->
    out = []
    for item in self
      out.push(item)
    out