call/cc

Is it worth the implementation cost, or are native coroutines good enough for most usecases?

Delimited continuations please, and put in an unwind-protect on garbage collection or explicit last call.

my other call/cc is a cdr

>>1

Continuations eliminate stack, so
1. No stack-trace, complicating debugging order of magnitude.
2. Object destructors depends on stack being linear. No with-open-file or using(var memory = malloc(size)).
3. GC is a must, because you can't depend on stack pop-ing anymore.
4. CPS-transformation requires optimizing compiler eliminating useless closures.

coroutines are a decent compromise.

>>4

1. No stack-trace, complicating debugging order of magnitude.

Most optimizations make stack traces useless.

3. GC is a must, because you can't depend on stack pop-ing anymore.

GC is a must regardless.

4. CPS-transformation requires optimizing compiler eliminating useless closures.

Most compilation subprobles turn out to be NP-hard or halting-complete, yet in practise can be solved fairly efficiently.