# async calls sequentalization

apply = (f, s) -> () -> f( () -> s() )
id    = (args...) -> args
foldr = (f, z, [x, xs...]) -> if x then f x, (foldr f, z, xs) else z
chain = (funcs...) -> (foldr apply, id, funcs)()

action1 = (done) ->
  async_action_with_callback(done)

action2 = (done) ->
  async_action_with_callback(done)

# ...

actionN = (done) ->
  async_action_with_callback(done)

chain action1, action2, ..., actionN