Re: [boost] bind()ing to member *data*

From: Thomas Witt (witt_at_[hidden])
Date: 2002-02-21 07:59:39

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You may have a look at msg 25611 
"Tuple extension proposal" it tries to solve your problem
in a different way.

On Thursday 21 February 2002 00:15, jkharris01 wrote:
> Should bind() be extended to include binding to member data?  If it
> already allows convenient binding to member functions, wouldn't
> member data be a natural extension?
>
> The specific problem that got me thinking about this is that I
> couldn't find an easy way to make a predicate compare only
> the ".second" member of a pair, as in a map lookup by value:
>
>     typedef std::map<int,float> map_t;
>
>     // find the map entry whose value is 3.14
>     void findpi(const map_t& themap)
>     {
>         std::find_if(themap.begin(), themap.end(),
>                      member_equal(&map_t::value_type::second, 3.14));
>     }
>

This would be

     void findpi(const map_t& themap)
     {
         find(make_select_iterator<1>(themap.begin()),
              make_select_iterator<1>(themap.end()),
              3.14);
     }

Thomas

- -- 
Dipl.-Ing. Thomas Witt
Institut fuer Verkehrswesen, Eisenbahnbau und -betrieb, Universitaet Hannover
voice: [phone] - 4273, fax: [phone]
http://www.ive.uni-hannover.de
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