>>  Piers Cawley <pdcaw...@bofh.org.uk> wrote:

>>>  When you make a full continuation with clone, can't you chase up its
>>>  continuation chain and mark its reachable continuations (and only those
>>>  continuations) as non recyclable? (This is one of the reasons I think
>>>  that a Continuation should have an explicit copy of the continuation
>>>  that was current when it was made, rather than relying on
>>>  savetop/pushtopp to capture it.)

>>  We need getting at the call chain anyway. But storing P1 elsewhere seems
>>  not to be the right thing. OTOH a subroutine using integers only would
>>  preserve it's context just with C<pushtopi>, if P1 is saved elsewhere.
>>  Your proposal smells like: the return continuation is normally hidden
>>  (i.e.  not in any register, just in the context). Some opcode like
>>  C<get_current_cont> makes it available for backtracking or such.

>That certainly makes sense to me; can anyone think of cases where
>having/making an explicit return continuation is a good thing?