On Jun 27, 2007, at 10:32 AM, Bradley Lucier wrote:

Marc:

Is there some combination of continuation-capture and continuation-graft that gives the semantics of call/ec?

Yes, since call/cc is built on top of the continution-XXX primitives and the following is a valid definition of call/ec:

(define call/ec call/cc)

The thing is that this implementation does not take advantage of the usage constraints of call/ec . It would be possible to implement call/ec in such a way that it does minimal heap allocation.

To be honest, I don't understand what any of call/ec, continuation-capture, and continuation-graft do.

Check out my paper "A Better API for First-Class Continuations" (http://repository.readscheme.org/ftp/papers/sw2001/feeley.ps.gz) for the continuation-XXX operations.

Marc