Re: Dynamic variables

[will@cs.uoregon.edu]

Pavel observed that DYNAMIC-WIND sufficed to implement a portable
shallow-binding implementation of the BASH proposal for all
single-processor implementations of Scheme, but claimed that
multiprocessor implementations will have to implement it more
primitively.

I observe that DYNAMIC-WIND suffices to implement a portable
deep-binding implementation of the BASH proposal.  It seems to
me that this deep-binding implementation should work for most
multiprocessor implementations as well, provided the "right"
relationship exists between processes and continuations.  Some
multiprocessor implementations might want to implement things
more primitively, either for efficiency or because their view
of what is right differs from mine.

Neither the deep-binding nor the shallow-binding implementation
in terms of DYNAMIC-WIND seems capable of supporting a tail-call
semantics for CALL-WITH-DYNAMIC-BINDING.

Peace, Will