[r6rs-discuss] Laziness Features

[Eli Barzilay]

On Oct 16, John Cowan wrote:
> Eli Barzilay scripsit:
> 
> > [One real problem in saying this: since this is now in a library, it
> > is even more questionable to keep these bullets, because implementing
> > them requires changes to the core implementation.]
> 
> Implementing the mutable-pairs library will require changes to the
> core implementation, in the case of an implementation which does not
> support mutable pairs unless the library is included.

Good point, but I should add:

* Mutable pairs are in some sense a smaller change to the core than
  implicitly forced values (changing a data type, vs changing an
  evaluation rule).  (IMO, of course.  If GCs are the main thing that
  you're interested in, then you'll probably disagree.)

* Mutable pairs come with an extensive description -- even when the
  implications are pretty obvious; the implicit force thing (with
  implications that are more subtle) is left as a single paragraph
  with three bullets, nothing more.

-- 
          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                  http://www.barzilay.org/                 Maze is Life!