Thanks to Steven and my own thinking a solution:
#include <iostream>
#include <map>
#include
#include
#include
#include
#include
#include <functional>
template< typename Key, typename Value, typename Predicate >
std::map< Key, Value > copy_if( const std::map< Key, Value >& aMap, const Predicate& aPredicate)
{
using namespace std;
using namespace boost::lambda;
pair< typename map< Key, Value >::iterator, bool > (map< Key, Value >::*InsertFn)(const typename map< Key, Value >::value_type&) = &map< Key, Value >::insert;
map matchedObjects;
for_each( aMap.begin(),
aMap.end(),
if_then(
bind( aPredicate, _1),
bind( InsertFn,
&matchedObjects ,
bind( &make_pair< typename std::map < Key, Value >::key_type,typename map< Key, Value >::mapped_type >,
bind(&map< Key, Value >::value_type::first, _1),
bind(&map< Key, Value >::value_type::second,_1)))));
return matchedObjects;
}
int main( int argc,
char* argv[])
{
std::map objectsMap;
objectsMap.insert(std::make_pair("one","value1"));
objectsMap.insert(std::make_pair("two","value2"));
objectsMap.insert(std::make_pair("three","value3"));
boost::function< bool (std::map::value_type)> mapPredicate = boost::lambda::bind(&std::map::value_type::second,boost::lambda::_1) == "value3";
std::map matchedObjectsMap = copy_if(objectsMap,mapPredicate);
std::for_each( matchedObjectsMap.begin(),
matchedObjectsMap.end(),
std::cout << boost::lambda::bind(&std::map::value_type::first, boost::lambda::_1) << boost::lambda::constant(" ") << boost::lambda::bind(&std::map::value_type::second, boost::lambda::_1) << '\n');
return 0;
}
--
Groeten,
Joost Kraaijeveld
Askesis B.V.
Molukkenstraat 14
6524NB Nijmegen
tel: 024-3888063 / 06-51855277
fax: 024-3608416
web: www.askesis.nl
