Editing Coroutine (section)

===Mutual recursion===
{{Further|Mutual recursion}}
Using coroutines for state machines or concurrency is similar to using [[mutual recursion]] with [[tail call]]s, as in both cases the control changes to a different one of a set of routines. However, coroutines are more flexible and generally more efficient. Since coroutines yield rather than return, and then resume execution rather than restarting from the beginning, they are able to hold state, both variables (as in a closure) and execution point, and yields are not limited to being in tail position; mutually recursive subroutines must either use shared variables or pass state as parameters. Further, each mutually recursive call of a subroutine requires a new stack frame (unless [[tail call elimination]] is implemented), while passing control between coroutines uses the existing contexts and can be implemented simply by a jump.