<jose.diego@gmail.com> wrote in message
news:1155678420.260516.259860@74g2000cwt.googlegroups.com...
I made the following function to access a map elements to simulate the
operator[] in a const map
template<typename MapType>
const MapType::value_type::second_type get(const MapType map, const
MapType::value_type::first_type value) {
MapType::const_iterator it = map.find(value);
if( it == map.end() ) return MapType::value_type::second_type();
return *it;
}
If the std::map<>::operator[] could be used as an rvalue, it could have
the above implementation
What do you think?
Your solution is already problematic because it breaks the standardized
behavior. It's highly unlikely that the committee will choose to make changes
that break a lot of code. On the other hand, no clear logic dictates whether a
new element should or should not be added to the map or the exception should be
thrown when operator [] is invoked for non-existing element. I personally would
prefer exception, but in the final analysis it's not important. Using iterators
is more logical with associative containers and doesn't have any of these
problems, and that's what people are accustomed to doing - using find(),
lower/upper_bound(), etc.
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