> Well, I think Python's iterators, especially the generators, are beautiful. > More importantly, I think there is no general way to make iterators > copyable, regardless of the programming language. The problem is that most > of the useful ones depend on external state. > > Peter
Hmm, but tee() de facto do it (clone iterator) and ignore side-effects of iterator ("external" state). And tee() create independent **internal** state of iterator (current position). But **external** state - is headache of programmer. So, iterator/generator have to be method for copy itself (the tee() implementation) or be "re- startable". Why not? Concrete problem was to generate iterators (iterator of slices). It was solved with ReIter. --Best regards, --pavel -- http://mail.python.org/mailman/listinfo/python-list