Closures

[Jonathan Rees <Rees at YALE>]

						... Can the Scheme
    hackers out there explain to us which uses of dynamic closure are
    subsumed under lexical closure and which uses really need the dynamic
    closures?

I've been using Scheme-style closures heavily for a couple of years now and
can attest to their wonderfulness.  I am tempted to say that they are
sufficient to handle the applications to which Lisp Machine-style
closures are put, but I say this from a position of weakness since I've
never actually used the other kind of closure.  I suspect that it is the
case that there's no hacker out there who has extensive experience with
both beasts; such a person would be the one to consult.  All I can say
is that I've never felt the need to close over special variables.  Name
the application - I believe Scheme closures work as well if not better
than other kinds.

As many of you know, I'm quite biased on this matter.  But as
implementor and user I strongly advise against the inclusion of Lisp
Machine-style closures in the language.

				Jonathan Rees
				Scheme Hacker