On Wed, 2007-10-10 at 08:39 +0100, Hugo Ferreira wrote:

> # let exp = gen_events |> gen_states |> analyze_data |> check_stop ;;
> val exp : '_a -> unit = <fun>
> 
> And execute it so:
> 
> # let start_state = () ;;
> val start_state : unit = ()
> 
> # let _ = exp start_state ;;
> - : unit = ()

> My question is: how can one design and implement such a "pull pipe" and
> solve the problem I have of propagating state back to a previous
> function. 

Assume 

	f : state_t -> state_t option

is your state transformer, then

	let rec go state = 
		match f state with 
		| Some state -> go state
		| None -> ()
		
will do it.

-- 
John Skaller <skaller at users dot sf dot net>
Felix, successor to C++: http://felix.sf.net