[boost] Re: Formal Review: FOREACH macro

From: Arkadiy Vertleyb (vertleyb_at_[hidden])
Date: 2005-05-02 10:10:53

"Andy Little" <andy_at_[hidden]> wrote

> > FWIW A naive method to do the above is as:
> >
> > #define FOR_EACH(cont) \
> >    for (BOOST_TYPEOF( cont )>::iterator _ = cont ## .begin();\
> >            _ != cont ## .end();\
> >            ++ _ )
>
> FWIW  the following seems to do the job including  for c-style strings and
const
> containers. Is the BOOST_FOREACH complexity necessary?
>
>  (Again I prefer the lambda style iterator, for versatlity ... )
>
> #include <boost/typeof/typeof.hpp>
> #include <boost/range/begin.hpp>
> #include <boost/range/end.hpp>
>
> #define FOR_EACH(cont) \
>     for (BOOST_AUTO( _ , boost::begin(cont) );\
>             _ != boost::end(cont);\
>             ++ _ )
>
> int main()
> {
>     const char * test = "hello";
>     FOR_EACH(test){
>         if ( _ ==  boost::begin(test) ){
>             std::cout<<  "[";
>         }
>         std::cout  << *_;
>         if( std::distance( _ , boost::end(test) ) > 1){
>             std::cout  <<',';
>         }
>         else {
>             std::cout << ']';
>         }
>     }
> }
>
> Are there advantages to the BOOST_FOREACH  approach?

It doesn't require type/template registration.

Regards,
Arkadiy