sub f {
    my $position_of_caller = return 3; # f() will be '3', eventually
    my $alternative = return 5; # f() will be '5', eventually

    print "Now we return a value:";
    $alternative->(); # return 5 to caller

    # will we get here? Possibly, through the "yield" call.
CONTINUATION:
    print "We are continuing here?";
};

f();
yield; # transfers control to the label CONTINUATION