more playing.coffee

map = (list, func = ((x, i, l) -> x)) ->
  result = (func(elem, index, list) for elem, index in list)
  return result

each = (list, func) ->
  map(list, func)
  return

filter = (list, func = ((x, i, l) -> x)) ->
  result = []
  ((if func(elem, index, list) then result.push(elem)) for elem, index in list)
  return result

reduce = (list, func = ((x, i, l) -> x), initial = 0) ->
  result = initial
  each(list, (elem, index, list) -> result = func(result, elem, list); return)
  result

reduceRight = (list, func, initial = 0) ->
  reduce(list.reverse(), func, initial)

some = (list, func = ((x, i, l) -> x)) ->
  result = false
  each(list, (elem, index, list) -> result = true if func(elem, index, list))
  return result

every = (list, func = ((x, i, l) -> x)) ->
  flip = (elem, index, list) -> !func(elem, index, list)
  !some(list, flip)

a = [0, 1, 2, 3, 4, 5]

x = filter(a, (elem) -> elem % 2 == 0)
y = map(x, (elem) -> elem + 1)
z = map(x, (elem) -> elem + 5)

j = reduce(a, (p, c) -> p + c)
k = some(a, (elem) -> elem == 1)
l = every(a, (elem) -> elem < 6)

console.log 'list a', a
console.log 'x filter a', x
console.log 'y map x', y
console.log 'z map x', z
console.log 'j reduce a', j
console.log 'k some a', k
console.log 'l every a', l

each(y, (elem) -> console.log('each y', elem))
each(z, (elem) -> console.log('each z', elem))