(yield (? v #n)) v: any type (optional)
Yields a value from a coroutine.
yield form is evaluated, the coroutine is paused, yielding
coro-run is used to resume execution of the coroutine, the
finishes evaluating, returning the argument which was passed to
It's an error if
yield is called without an enclosing
fn form - for example,
at the toplevel of a source file.
The presence of a
yield form in the body of a
fn form is what differentiates a
coroutine function from a normal function. When a coroutine
function is called, it returns a new coroutine which is paused at the
beginning of the function's body.