Re: [boost] small addition to functional

From: Peter Dimov (pdimov_at_[hidden])
Date: 2004-03-09 07:59:17

John Torjo wrote:
> Sorry, I mis-explained.
> For boost::bind, the above works like a bliss.
> 
> It will have problems working with other code, that uses result_type.
> For example, boost::transform_iterator:
> 
> #include <boost/bind.hpp>
> #include <boost/iterator/transform_iterator.hpp>
> using namespace boost;
> #include <algorithm>
> #include <vector>
> #include <string>
> 
> struct test { std::string s; };
> 
> void clear_s( std::string & s) { s.erase(); }
> 
> int main(int argc, char* argv[])
> {
>     std::vector<test> v;
>     std::for_each(
>         // of course, it would be simpler to use Range Template
>         Library :D
>         make_transform_iterator(v.begin(),mem_fn(&test::s)),
>         make_transform_iterator(v.end(),mem_fn(&test::s)), clear_s);
> 
>     return 0;
> }

Your examples are getting more and more contrived. ;-)

To override the result_type, you'll need once again to revert to

    bind<std::string&>(mem_fn(&test::s), _1)

instead of mem_fn(&test::s).

If you do a "cvs update" you'll also be able to shorten it to

    bind<std::string&>(&test::s, _1)