Comment by harryposner

So the particular example here isn’t too different from exceptions. You’re unwinding the stack up to a predefined point— here, the callsite of foo, where with exceptions it would be up to the surrounding try/catch. Scala actually implements non-local returns (the only practical use I’ve had for call/cc) using exceptions: https://tpolecat.github.io/2014/05/09/return.html