Re: Non-stack-copying call-with-current-continuation?

[Noah Lavine]

Hello,

> IIRC, the stack copying in Guile's continuation implementation is
> inevitable. Though it's inefficient, the consideration is to cooperate with
> other languages such as C.

It's inevitable in the general case, where the continuation might
return multiple times.

However, in this situation, he knows the continuation will only ever
return once, so it is not necessary to copy the stack. This control
structure will be the equivalent of setjmp and longjmp in C.

Prompts have an optimization where they don't actually copy the stack
if it is clear that they can only return once. That is why catch and
throw are implemented that way.

Noah