extending 'import' using 'with'

[Dennis Ritchie via Digitalmars-d]

On Wednesday, 1 April 2015 at 13:35:22 UTC, ketmar wrote:
> people with Java/C/C++/etc. background tend to forget about the 
> power of
> metaprogramming: they have no such tool at hand, so they don't 
> even think
> about it.

C++ with boost:

-----
#include <iostream>

#include <boost/preprocessor/cat.hpp>
#include <boost/preprocessor/seq/for_each.hpp>

namespace a { namespace b {
     namespace x {
       int test1 = 1;
     }
     namespace y {
       int test2 = 2;
     }
     namespace z {
       int test3 = 3;
     }
   }
}

#define USE_NAMESPACES_IMPL( r, root, name ) \
   using namespace root :: name;

#define USE_NAMESPACES( root, names ) \
   BOOST_PP_SEQ_FOR_EACH( USE_NAMESPACES_IMPL, root, names )

USE_NAMESPACES( a::b, (x)(y)(z) )

int main() {

   std::cout << test1 << '\n'; // 1
   std::cout << test2 << '\n'; // 2
   std::cout << test3 << '\n'; // 3

   return 0;
}
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http://ideone.com/LncucP