applyhook

["Scott E. Fahlman" <Fahlman@CMU-CS-C.ARPA>]

I'm not sure why GSB's mail about ((lambda ...) ...) being the reason
for the env argument to applyhook is relevant and my note pointing out
the same problem is not.  I hope the various mailers are not losing
things again.  But anyway...

If this is the only problem that people have found, and as far as I know
it is, then Moon's suggestion of passing the lambda form in to the
applyhook as an instant closure would work OK, and would not hurt
performance in the normal case, since if there's a non-null applyhook a
different calling sequence must be used in any event.  (The args must go
into a list rather than onto the stack.)

My only remaining question is whether it is worth the hassle to
eliminate the env argument just because it is possible to do so.  This
seems to be a gratuitous change (not a clarification) from the published
specification for no particularly compelling reason.  It will cause
confusion among implementors (and perhaps a few users) who are not on
this mailing list and who do not hear about this change.  Until some
sort of formal means of announcing changes to the spec is set up, we
should probably avoid incompatible changes unless the reason for making
the change is really compelling.

-- Scott