iterating an interator partially then resuming

[Skaperen]

i would like to iterate an iterator in a loop that will usually break out part way through. then later, i want another loop to resume that iteration from where the first one left off. how hard is this to do? what if there is a different need between these loops, perhaps in a function, to iterate that iterator from the beginning, maybe stopping at a different position? what seems like it would be useful is something that can make a stateful view of an iterator.