Re: [boost] Re: iterator_adaptor library bug

From: David Abrahams (david.abrahams_at_[hidden])
Date: 2001-07-10 16:53:07

Better, but still not what I had in mind. I think the metaprogram ought to
go in indirect_iterator_generator so it can be used to select the right
value type even when the generator is used.

make_indirect_iterator is /supposed/ to be portable to MSVC; it just isn't
;-(. I think it could be made to work for some obvious cases, with a little
effort. Not sure if it's worth it, though.

-Dave

----- Original Message -----
From: "Alexander Belopolsky" <belopols_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Tuesday, July 10, 2001 3:50 PM
Subject: [boost] Re: iterator_adaptor library bug

> --- In boost_at_y..., "David Abrahams" <david.abrahams_at_r...> wrote:
> > I'm afraid it's not the right approach. The value_type of a constant
> > iterator to T should just be T, not const T. You need to arrange for
> T
> > const* and T const& pointer and reference parameters, respectively.
> >
> >
>
> Thanks, Dave.
>
> Here is an alternative fix:
>
> > cvs diff iterator_adaptors.hpp
> Index: iterator_adaptors.hpp
> ===================================================================
> RCS file: /cvsroot/boost/boost/boost/iterator_adaptors.hpp,v
> retrieving revision 1.42
> diff -r1.42 iterator_adaptors.hpp
> 928a929
> >
> 931c932,944
> < inline typename indirect_iterator_generator<OuterIterator>::type
> ---
> > struct indirect_iterator_selector {
> >   typedef typename
> detail::iterator_traits<OuterIterator>::value_type OuterValue;
> >   enum { inner_is_const = is_const<typename
> remove_pointer<OuterValue>::type>::value };
> >   typedef typename
> boost::detail::if_true<(inner_is_const)>::template
> >   then<
> >   indirect_iterator_pair_generator<OuterIterator>::const_iterator,
> >   // else
> >   indirect_iterator_pair_generator<OuterIterator>::iterator
> >   >::type type;
> > };
> >
> > template <class OuterIterator>
> > inline typename indirect_iterator_selector<OuterIterator>::type
> 934,935c947
> <     typedef typename indirect_iterator_generator
> <         <OuterIterator>::type result_t;
> ---
> >     typedef typename indirect_iterator_selector<OuterIterator>::type
> result_t;
>
> make_indirect_iterator is inside #ifndef BOOST_MSVC which
> probably means that it is not supposed to be portable to
> that platform to begin with.
>
>
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