Re: [Boost-users] updating mpl::map to 1.34

14 Dec 2006

      Now I have a question regarding iteration through the map. Would you expect this sample to work:

	typedef mpl::map
			<
				mpl::pair
			,	mpl::pair
			,	mpl::pair
			,	mpl::pair
			>			seq_t;

	typedef mpl::begin::type		begin_map;
	typedef mpl::apply
		<
			mpl::insert
			, mpl::vector<>
			, begin_map
		>::type				vector_with_one_elem;

It fails with 147 compilation errors.

Top errors look like:

c:\boost\include\boost-1_33_1\boost\mpl\aux_\preprocessed\plain\reverse_fold_impl.hpp(203) : error
C2039: 'type' : is not a member of 'boost::mpl::next<T>'
        with
        [
            T=boost::mpl::m_iter
        ]
        c:\boost\include\boost-1_33_1\boost\mpl\aux_\preprocessed\plain\reverse_fold_impl.hpp(212)
: see reference to class template instantiation
'boost::mpl::aux::reverse_fold_impl' being
compiled
        with
        [
            N=-1,
            First=boost::mpl::m_iter,
            Last=boost::mpl::v_iterboost::mpl::na,0>,
            State=boost::mpl::vector0boost::mpl::na,
            BackwardOp=boost::mpl::push_frontboost::mpl::_,boost::mpl::_,
            ForwardOp=boost::mpl::arg<1>
        ]

Thanks a lot for your help!

Ovanes

On Thu, December 14, 2006 19:12, Ovanes Markarian wrote:
...
But my question would be: Would you see an advantage in this approach (with type derivation)? On
the other hand, if I could manipulate the types the same way in mpl::vector and mpl::map this
would be more clearer. I think vector should not support the derived types as well.
With Kind Regards,
Ovanes Markarian
On Thu, December 14, 2006 19:04, David Abrahams wrote:
...
"Ovanes Markarian"  writes:
...
I believe I found some problem, when I was writing the test cases ;) It is for sure responsible
for the reported misbehavior with max_element.
Well, I don't know how to deal with this issue, may be you can
advice smth. Map accepts sequence of type pair. Vector as well. My
approach was to think, as long as mpl::pair static interface (first,
second) is valid I can use another class as well.
Clearly from your experiments you can see that you can't actually do
that.
--
Dave Abrahams
Boost Consulting
www.boost-consulting.com
_______________________________________________
Boost-users mailing list
Boost-users@lists.boost.org
http://lists.boost.org/mailman/listinfo.cgi/boost-users
_______________________________________________
Boost-users mailing list
Boost-users@lists.boost.org
http://lists.boost.org/mailman/listinfo.cgi/boost-users