Re: [Boost-users] boost::sub_range vs boost::iterator_range

From: Victor A. Wagner Jr. (vawjr_at_[hidden])
Date: 2005-12-05 20:42:09

At 14:16 2005-12-05, François Duranleau wrote:
>Content-Type: TEXT/PLAIN; charset=ISO-8859-1; format=flowed
>X-MIME-Autoconverted: from 8bit to 
>quoted-printable by milliways.osl.iu.edu id jB5LNecL002899
>
>On Sat, 3 Dec 2005, Victor A. Wagner Jr. wrote:
>
>>After reading (and re-reading a few times) the documentation on
>>range, it appears to me that there is little (if any) difference between:
>>boost::sub_range<T>
>>and
>>boost::iterator_range<T::iterator>
>
>Seems to me that sub_range is a convenience 
>class to describe iterator ranges from ranges or 
>containers that model ForwardRange, from which you can propagate constness.

yup, that's what I thought also

>>I've been working on a N way merge algorithm for work, and thought it
>>might be a nice chance to learn bost::range and maybe even get it
>>general enough to submit for boost utility some day.
>>At any rate.  Here's the problem:  I've written a test case and two
>>implementations (work still in progress) but I get compile errors
>>when I try to use  sub_range.
>>
>>the code can be found at  http://www.noidea128.org/sourcefiles/15646~
>>
>>to change the program from compiling/running the iterator_range to
>>sub_range simply change the lne from:
>>
>>Nway_merge(contain, ourmerged);
>>-to-
>>SNway_merge(contain, ourmerged);
>>
>>my compiler (VC-8_0) gives two errors which I cannot decipher.
>>Any assistance would be appreciated.... especially if I've
>>misunderstood why sub_range instead of iterator_range.
>
>Mm, I don't know. The only thing g++-4.0 (sorry, 
>I can't help you with VC) was complaining about 
>are the missing 'typename's for the declaration 
>of member_container_iterator and 
>iterator_range_iterator in Nway_merge, and 
>sub_range_iterator in SNway_merge. What are the 
>errors reported by the compiler?

I put in the typenames you (your compiler) 
suggested, that didn't fix the compile here... I still get:

1>------ Build started: Project: MergeTesting, 
Configuration: Release Win32 ------
1>Compiling...
1>MergeTesting.cpp
1>c:\boost\include\boost-1_33\boost/range/iterator_range.hpp(61) 
: error C2440: '<function-style-cast>' : cannot 
convert from 
'std::_Vector_const_iterator<_Ty,_Alloc>' to 
'std::_Vector_iterator<_Ty,_Alloc>'
1>        with
1>        [
1>            _Ty=int,
1>            _Alloc=std::allocator<int>
1>        ]
1>        No constructor could take the source 
type, or constructor overload resolution was ambiguous
1> 
c:\boost\include\boost-1_33\boost/range/iterator_range.hpp(238) 
: see reference to function template 
instantiation 'IteratorT 
boost::iterator_range_detail::iterator_range_impl<IteratorT>::adl_begin<const 
ForwardRange>(ForwardRange &)' being compiled
1>        with
1>        [
1>            IteratorT=std::_Vector_iterator<int,std::allocator<int>>,
1>            ForwardRange=boost::sub_range<member_container>
1>        ]
1> 
c:\boost\include\boost-1_33\boost/range/iterator_range.hpp(245) 
: see reference to function template 
instantiation 'boost::iterator_range<IteratorT> 
&boost::iterator_range<IteratorT>::operator 
=<boost::sub_range<ForwardRange>>(const 
boost::sub_range<ForwardRange> &)' being compiled
1>        with
1>        [
1>            IteratorT=std::_Vector_iterator<int,std::allocator<int>>,
1>            ForwardRange=member_container
1>        ]
1>        C:\Program Files\Microsoft Visual 
Studio 8\VC\include\xmemory(160) : while 
compiling class template member function 'void 
std::allocator<_Ty>::destroy(std::vector<int> *)'
1>        with
1>        [
1>            _Ty=ci
1>        ]
1>        C:\Program Files\Microsoft Visual 
Studio 8\VC\include\vector(416) : see reference 
to class template instantiation 'std::allocator<_Ty>' being compiled
1>        with
1>        [
1>            _Ty=ci
1>        ]
1>        C:\Program Files\Microsoft Visual 
Studio 8\VC\include\vector(426) : see reference 
to class template instantiation 'std::_Vector_val<_Ty,_Alloc>' being compiled
1>        with
1>        [
1>            _Ty=ci,
1>            _Alloc=std::allocator<ci>
1>        ]
1>        .\MergeTesting.cpp(21) : see reference 
to class template instantiation 'std::vector<_Ty>' being compiled
1>        with
1>        [
1>            _Ty=ci
1>        ]
1>c:\boost\include\boost-1_33\boost/range/iterator_range.hpp(68) 
: error C2440: '<function-style-cast>' : cannot 
convert from 
'std::_Vector_const_iterator<_Ty,_Alloc>' to 
'std::_Vector_iterator<_Ty,_Alloc>'
1>        with
1>        [
1>            _Ty=int,
1>            _Alloc=std::allocator<int>
1>        ]
1>        No constructor could take the source 
type, or constructor overload resolution was ambiguous
1> 
c:\boost\include\boost-1_33\boost/range/iterator_range.hpp(239) 
: see reference to function template 
instantiation 'IteratorT 
boost::iterator_range_detail::iterator_range_impl<IteratorT>::adl_end<const 
ForwardRange>(ForwardRange &)' being compiled
1>        with
1>        [
1>            IteratorT=std::_Vector_iterator<int,std::allocator<int>>,
1>            ForwardRange=boost::sub_range<member_container>
1>        ]
1>Build log was saved at 
"file://c:\Projects\Viper2005\MergeTesting\Release\BuildLog.htm"
1>MergeTesting - 2 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

I changed my compiler to use the latest 1_33_1 and I get:
1>------ Build started: Project: MergeTesting, 
Configuration: Release Win32 ------
1>Compiling...
1>MergeTesting.cpp
1>c:\boost\include\boost-1_33_1\boost/range/iterator_range.hpp(61) 
: error C2440: '<function-style-cast>' : cannot 
convert from 
'std::_Vector_const_iterator<_Ty,_Alloc>' to 
'std::_Vector_iterator<_Ty,_Alloc>'
1>        with
1>        [
1>            _Ty=int,
1>            _Alloc=std::allocator<int>
1>        ]
1>        No constructor could take the source 
type, or constructor overload resolution was ambiguous
1> 
c:\boost\include\boost-1_33_1\boost/range/iterator_range.hpp(238) 
: see reference to function template 
instantiation 'IteratorT 
boost::iterator_range_detail::iterator_range_impl<IteratorT>::adl_begin<const 
ForwardRange>(ForwardRange &)' being compiled
1>        with
1>        [
1>            IteratorT=std::_Vector_iterator<int,std::allocator<int>>,
1>            ForwardRange=boost::sub_range<member_container>
1>        ]
1> 
c:\boost\include\boost-1_33_1\boost/range/iterator_range.hpp(245) 
: see reference to function template 
instantiation 'boost::iterator_range<IteratorT> 
&boost::iterator_range<IteratorT>::operator 
=<boost::sub_range<ForwardRange>>(const 
boost::sub_range<ForwardRange> &)' being compiled
1>        with
1>        [
1>            IteratorT=std::_Vector_iterator<int,std::allocator<int>>,
1>            ForwardRange=member_container
1>        ]
1>        C:\Program Files\Microsoft Visual 
Studio 8\VC\include\xmemory(160) : while 
compiling class template member function 'void 
std::allocator<_Ty>::destroy(std::vector<int> *)'
1>        with
1>        [
1>            _Ty=ci
1>        ]
1>        C:\Program Files\Microsoft Visual 
Studio 8\VC\include\vector(416) : see reference 
to class template instantiation 'std::allocator<_Ty>' being compiled
1>        with
1>        [
1>            _Ty=ci
1>        ]
1>        C:\Program Files\Microsoft Visual 
Studio 8\VC\include\vector(426) : see reference 
to class template instantiation 'std::_Vector_val<_Ty,_Alloc>' being compiled
1>        with
1>        [
1>            _Ty=ci,
1>            _Alloc=std::allocator<ci>
1>        ]
1>        .\MergeTesting.cpp(21) : see reference 
to class template instantiation 'std::vector<_Ty>' being compiled
1>        with
1>        [
1>            _Ty=ci
1>        ]
1>c:\boost\include\boost-1_33_1\boost/range/iterator_range.hpp(68) 
: error C2440: '<function-style-cast>' : cannot 
convert from 
'std::_Vector_const_iterator<_Ty,_Alloc>' to 
'std::_Vector_iterator<_Ty,_Alloc>'
1>        with
1>        [
1>            _Ty=int,
1>            _Alloc=std::allocator<int>
1>        ]
1>        No constructor could take the source 
type, or constructor overload resolution was ambiguous
1> 
c:\boost\include\boost-1_33_1\boost/range/iterator_range.hpp(239) 
: see reference to function template 
instantiation 'IteratorT 
boost::iterator_range_detail::iterator_range_impl<IteratorT>::adl_end<const 
ForwardRange>(ForwardRange &)' being compiled
1>        with
1>        [
1>            IteratorT=std::_Vector_iterator<int,std::allocator<int>>,
1>            ForwardRange=boost::sub_range<member_container>
1>        ]
1>Build log was saved at 
"file://c:\Projects\Viper2005\MergeTesting\Release\BuildLog.htm"
1>MergeTesting - 2 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

>--
>François Duranleau
>LIGUM, Université de Montréal
>
>"There once was a boy who dreamed of being a hero,
>  who believed sincerely in the battle
>  to banish Darkness from a world of Light.
>  But Light and Darkness are equal,
>  and where one exists, so too must the other.
>  And when the boy finally realized this,
>  he had taken the first step toward being a true hero."
>                                                - from Record of Lodoss War
>
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Victor A. Wagner Jr.      http://rudbek.com
The five most dangerous words in the English language:
               "There oughta be a law"