Ray Dillinger scripsit: > The problem is that the two different models of non-local control > flow (exceptions, continuations) don't really play nice with > each other.
I continue to be baffled by this line of reasoning. Raising an exception in the R6RS/R7RS model (which is closely related to Common Lisp's) does *not* in itself constitute non-local control: it merely invokes a procedure which is the (current) value of a parameter. If that procedure, the exception handler, chooses to execute a non-local return, it must do so by way of a captured continuation, there being no other way to do it. (It's possible that under the covers the `guard` macro uses some other mechanism such as one-shot and/or delimited continuations that are available in the implementation.) -- We call nothing profound [email protected] that is not wittily expressed. John Cowan --Northrop Frye (improved) _______________________________________________ Scheme-reports mailing list [email protected] http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports
