> call/cc is a single instruction that is sufficiently expressive to implement e.g. exceptions, coroutines and lots of stuff for which people typically use mona

> call/cc is a single instruction that is sufficiently expressive to implement e.g. exceptions, coroutines and lots of stuff for which people typically use monad-style embeddings. The flip side of this is that call/cc prevents you from relying on a stack, except in cases where you can do heavy static analysis. And you virtually never need the full power of call/cc unless you're implementing coroutines. This is the main reason that so few languages support call/cc: stacks are a nice implementation technique (as opposed to GCed activation records on the heap), and call/cc comes with a heavy price for very situational value. One alternative are "escape" continuations, which can only be used during the lifetime of the creating block. These are stack friendly.