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Recursion on React.events.
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Date: 2009-12-09 (02:40)
From: Guillaume Yziquel <guillaume.yziquel@c...>
Subject: Recursion on React.events.

I've been dabbling with recursive definition of React events.

Suppose I have a function called schedule of type

	val schedule : Calendar.t -> unit React.event

which throws out an event at the specified time or date.

I've been trying to create a regular_schedule function that throws 
events at a regular pace. Daniel BĂĽnzli's module is great, but sometimes 
a bit rough to get by, specifically on examples such as this one.

So I came up with a recursive definition of such a React.event:

> let rec regular_schedule start_time period =
>   React.E.switch React.E.never begin React.E.map
>     begin fun () -> regular_schedule (Calendar.add (Calendar.now ()) period) period end
>     begin schedule start_time end
>   end

First question:

It almost works, in the sense that if you insert a print_endline after 
the fun (), well, it indeeds prints stuff on stdin at the specified 
pace. However, somehow, the event as a whole behaves as React.E.never. 
So it doesn't work. I guess it has to do with the way React.switch works 
synchronously, but I really do not get it.

Second question:

Is there somehow a notion of 'tail recursion' for such constructs?

All the best,

      Guillaume Yziquel