
Boost : 
Subject: Re: [boost] Wrapper around STL algorithms
From: TONGARI (tongari95_at_[hidden])
Date: 20101224 21:51:41
2010/12/25 Shevchenko Denis <for.dshevchenko_at_[hidden]>
> Hi friends!
>
> Between work on my Configurator (beta version on the way) I remembered an
> old idea to simplify work with STL algorithms. This is not a library, but
> just a simple wrapperaround algorithms from <algorithm> header. Main purpose
> of this  deliverance from direct work with iterators.
>
> Iterators is the perfect tool, but it is often a source of stupidmistakes:
>
> typedef std::vector< int > V;
> typedef V::iterator Vit;
> V v1 = list_of( 1 )( 2 )( 3 );
> Vitit1 = std::find( v1.begin(), v1.begin(), 2 ); // Oops, we use same
> iterator...
>
> V v2 = list_of( 34 )( 56 )( 78 );
> Vitit2 = std::find( v2.begin(), v1.end(), 56 ); // Oops, we use iterators
> from different containers...
>
> The most offensive is that such mistakes are not detected at compiletime
> (at least in GCC), because, strictly speaking,it is not language error, but
> logical error.Sometimes I make such mistakes in my code...
>
> Possible solution:
>
> template
> <
> typename Container
> , typename Value
> >
> inline typename Container::const_iterator
> simple_find( const Container& cont, const Value& value ) {
> return std::find( cont.begin(), cont.end(), value );
> }
>
> or like this:
>
> template
> <
> typename Container
> , typename Value
> >
> inline typename boost::range_iterator< const Container >::type
> simple_find( const Container& cont, const Value& value ) {
> return std::find( boost::begin( cont ), boost::end( cont ), value );
> }
>
> In this case we can write:
>
> V v1 = list_of( 1 )( 2 )( 3 );
> Vitit1 = simple_find( v1, 2 );
>
> V v2 = list_of( 34 )( 56 )( 78 );
> Vitit2 = simple_find( v2, 56 );
>
> Similarly possible to wrap all of the standard algorithms, that will
> simplify code and improve its reliability.
>
> Additionally it is possible to simplify the writing of standard idioms, for
> example:
>
> template
> <
> typename Container
> , typename Value
> >
> inline void simple_erase_all( Container& cont, const Value& value ) {
> cont.erase( std::remove( boost::begin( cont ), boost::end( cont ), value ),
> boost::end( cont ) );
> }
>
> Example of code:
>
> V v3 = list_of( 111 )( 333)( 333 );
> simple_erase_all( v3, 333 );
>
> I think that this wrapper could be a part ofBoost.Utility.
>
> What do you think about it?
>
>
If I understand correctly, you might want to take a look into Boost.Range.
See:
http://www.boost.org/doc/libs/1_45_0/libs/range/doc/html/range/reference/algorithms.html
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