Re: [stack] disallowing recursive definitions

On Mar 3, 2008, at 19:50 , William Tanksley, Jr wrote:

> John Cowan <[email protected]> wrote:
>> William Tanksley, Jr scripsit:
>>> Now, interestingly, a concatenative tail-call cannot do this. Does
>>> this imply some superiority for concatenative optimizers? :-)
>
> I'll reply to both of your messages in one.
>
>>  No.  All you do is do an arbitrary stack shuffle before the tail  
>> call.
>
> Then the analysis difficulty (if there is any) is obviously in the
> shuffle, not in the tail-call. The analytical problem with an
> applicative tail-call is that the 'shuffle' happens at the same time
> as the call.
>
>> With a concatenative tail-call you're passing the stack as an
>> argument. In other words, you pass the entire state of the program!
>
> Yes, this is how concatenative languages are modeled. That's how
> *every* step in their execution is modeled, not just tail-calls or
> calls. If this were a problem, concatenative languages would be
> universally problematic, not merely problematic in the presence of
> tail-calls.

A few months back, I finally caught on to this: by their nature,
concatenative languages enforce computation by continuation
passing. Would it be true to say there is no other way?
--
don



>
>>  John Cowan        http://www.ccil.org/~cowan          [email protected]
>
> -Wm
>
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