It's sometimes useful to be able to reverse the contents of the stack. Parable now provides for this via rso.
1 2 3
At this point 3 is on the top of the stack. If we want to discard the 1, we could do something like:
[ nip ] dip
rso drop rso
This becomes more useful when the stack is deeper. Perhaps it'd also be nice to have something like this to do the above (where invoke<rso> reverses the stack before and after execution of the pointer):
I'll have to consider this a bit more.