[boost] [range] transform surprise

Subject: [boost] [range] transform surprise
From: Neal Becker (ndbecker2_at_[hidden])
Date: 2011-03-05 09:27:16

I'm surprised that boost::range::transform args are

template<
    class SinglePassRange1,
    class OutputIterator,
    class UnaryOperation
>
OutputIterator transform(const SinglePassRange1& rng,
                         OutputIterator out,
                         UnaryOperation fun);

I would have expected:

template<
    class SinglePassRange1,
    class SinglePassRange2,
    class UnaryOperation
>
OutputIterator transform(const SinglePassRange1& rng,
                         SinglePassRange2& out,
                         UnaryOperation fun);

Why the asymmetry?