[Boost-users] Implementing Range Adaptor or "transformation" iterator

I see the documentation "doc/html/range/reference/extending/method_3/method_3_1.html" and want to do something like that. The Adaptor I want to write will transform the elements and provide a lazy transformed view. So, I need the return range to be a pair of transformed iterators, and a transform iterator works just like the underlying iterator only the * operator will apply my function to the value as it fetches it. But, it seems to me that there should be something like that already. Is there something I'm overlooking in STL or in some other Boost library? Thanks, —John