stream_test.coffee

class Batman.Cons extends Batman.Object
  @accessor (key) ->
    return unless key.match(/^c[ad][ad]+r$/)
    @get("c#{key[1]}r.c#{key[2..key.length-2]}r")
  @accessor 'car', -> @car
  @accessor 'cdr', -> @cdr
  constructor: (@car, @cdr) ->

class Batman.Stream extends Batman.Cons
  @accessor 'cdr', -> @cdrFunction()
  constructor: (@car, @cdrFunction) ->

QUnit.module 'Batman.Stream'

test "a stream of fibonacci numbers", ->
  fibgen = (a,b) -> new Batman.Stream a, -> fibgen(b, a+b)
  fibs = fibgen(0,1)
  
  equal fibs.get('car'), 0
  equal fibs.get('cdr.car'), 1
  equal fibs.get('cdr.cdr.car'), 1
  
  # backwards from lisp because property access goes left-to-right:
  equal fibs.get('cdddar'), 2
  equal fibs.get('cddddar'), 3
  equal fibs.get('cdddddar'), 5