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Re: Much simpler leak-free implementation possible?

This page is part of the web mail archives of SRFI 40 from before July 7th, 2015. The new archives for SRFI 40 contain all messages, not just those from before July 7th, 2015.

Hello Phil,

Thank you very much for your insights.  
> I encourage you to extend your proof-of-concept to a full reference
> implementation.  

Thank you for the invitation.  I'll see what I can do, if time allows.  

> Second, you will need to decide on and implement some abstraction
> that hides the underlying cps mechanism.  

Yes.  I've been thinking about that.  I have some untested ideas, but
as you noted, I'm not sure they fit well with the traditional stream API
(e.g. having to use car/cdr instead of stream-car, stream-cdr).  The
result might not be suitable for this SRFI.      

> I belive your characterization of your stream-unfold as "trivial" and
> "vastly simpler" than the one in the srfi reference implementation
> is unfair, because you solve a considerably simpler problem. 


> I can tell you that times3 runs to completion and correctly
> evaluates (times3 1000000) on my Windows 98 machine, using
> both MzScheme and Petite Chez Scheme, without thrashing
> the hard disk looking for memory, ...

This is also true on my machine.  However, when I try 
(times3 100000000), I do run out of memory (it is easy to see in the
performance tab of the Windows task manager that the memory consumed
increases up to >400MB, at which point it starts thrashing).  Perhaps I'm
doing something wrong.  Are you using the definition?

  (define from0 
     (let loop ((x 0))
         (stream-cons x (loop (+ x 1))))))

The CPS solution does not have the same problem on my machine.  It just
seems to run forever with pretty much flat space consumption.    

Best regards