Re: [boost] Lazy list

Subject: Re: [boost] Lazy list
From: Zachary Turner (divisortheory_at_[hidden])
Date: 2009-01-18 12:38:41

On Sun, Jan 18, 2009 at 6:14 AM, Sebastian Redl <
sebastian.redl_at_[hidden]> wrote:

> Zachary Turner wrote:
> > Has this been considered before, and can anyone think of any technical
> > limitations that would prevent such a class to be written?
> >
>
> Do you have a motivating use case for such lists?
>
> Sebastian
>

I don't have an immediate need for one if that's what you mean, but in the
past when I have done programming in functional languages I have always
found them extraordinarily useful and would find uses for them even when I
wasn't really expecting to.  These days, however, I do much less
mathematical / scientific programming which is where they tend to find most
of their applications.  While it is not exactly a practical usage, one of
the easiest-to-describe problems that lazy lists provide a particularly
elegant solution to is ascending order generation of hamming numbers.

I'm not quite sure I agree though that it's simply a functional "idiom".  I
think it's a general programming idiom, that just so happens to be easier to
implement in functional languages.  But even Mpl has started to adopt
certain aspects of lazy evaluation.  I think lazy lists can allow elegant
and expressive specification and description of problems that can otherwise
be quite difficult to express without them, regardless of language.  But of
course if it really isn't practical to implement in C++ then I can just
scratch the idea :)