> On 26 Mar 2003, Anthony Williams wrote: > > It strikes me that if you dereference n iterators, > you have n values, and the > most natural way to store them is a tuple.
--- Douglas Paul Gregor <[EMAIL PROTECTED]> wrote: > I would agree if tuples and argument passing were > more closely linked, > i.e., if passing a tuple to a function meant that > the tuple would be > automagically unpacked into separate arguments. >From a user's point of view, this seems a very strong argument to me. For instance, in my software, I use combining iterators with functionals such as std::divides. If I were forced to accept my arguments as a tuple, I couldn't use any of these functionals without the extra unpacking step. Besides, introducing the tuple in the middle between dereferencing the iterators introduces the possibility of inadvertent extra value copies. Another big headache for the user. And why all that? I really don't see any advantage to this intermediate step of packaging the derefernced iterators into a tuple, only to unpack it in 99.999% of the cases. What for? Once again: The big picture is that we want an iterator that parallel-iterates over several sequences and upon dereferencing, applies some processing to the dereferenced iterator. This processing is specified by the user via a fuctional. One of the many, many things that such a functional can do is package the arguments into a tuple, if that is what's needed. (Although we still haven't seen a single real-life request for that). Why on earth would I, in the general case, introduce a packaging/unpackaging step in the middle between dereferencing the iterators and passing them to the functional? Am I missing something? BTW, Anthony: In one of my CUJ columns, I made a big fool of myself by gratuitously packaging function arguments into a tuple, and I seem to remember that you were one of the people who pointed this out to me. Looks like we switched sides in this argument... ;-) Thomas Becker Zephyr Associates, Inc. Zephyr Cove, NV __________________________________________________ Do you Yahoo!? Yahoo! Platinum - Watch CBS' NCAA March Madness, live on your desktop! http://platinum.yahoo.com _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost
