Coroutines rely on "pausable" workalikes for control flow functions
while, and so on.
pausables() scans for and returns
a list of all pausable functions visible from the present
pausables(envir = caller(), packages = NULL)
The environment to search (defaulting to the calling environment).
By default, will only look for pausable functions
visible from the caller's environment.
additionally specifies aditional packages to
packages=base::.packages() will search all currently
[.packages(all.available=TRUE)] will search
all installped package.
A list of expressions (either names or
A pausable function is a public function that has a corresponding
private function with a name endng with
_cps. Most of these
private functions are defined in
async source file
async:::for_cps contains the pausable implementation of