src/pmc/retcontinuation.pmc - Return Continuation
RetContinuation extends Continuation.
A return continuation is a one shot Continuation,
it gets recycled immediately after invocation.
void init() 
- Initializes the continuation.
 
PMC *clone 
- Return a new Continuation PMC with the context of SELF.
Note: the returned object is not a RetContinuation and creating a real Continuation invalidates all RetContinuation all the way up the call chain that is,
these can't be recycled,
they get persistent until the GC gets at them.
 
void *invoke(void *next) 
- Transfers control to the calling context,
and frees the current context.
 
Initial revision by sean 2002/08/04.