Hi Viktor,
2013/6/5 Viktor Sehr
I'd like to suggest the addition of a default value to the range access adaptors. Either by adding it as an extra, non-necessary parameter for the functions, or by duplicating the functions as "front_or_default(T default value)".
For example it would be useful for finding objects which I am not sure exists in a range.
std::vector<int> vec = boost::assign::list_of(2)(4)(6); auto first_odd = vec | filtered(is_odd) | front(); // undefined? auto first_odd = vec | filtered(is_odd) | front_or_default(-1); // everything is fine!
Another option would be a function which returns the adress, or nullptr if the value does not exist?
/Viktor
My Boost.Range Extension has `front` accessor.
http://dl.dropboxusercontent.com/u/1682460/git/OvenToBoost/libs/range/doc/ht...
https://github.com/faithandbrave/OvenToBoost/tree/master/boost/range/access
This is now proposing to Boost.Range.
However, I don't have `front_or_default` feature.
I think better way is add `optional_front` feature (return
boost::optional
======================== Akira Takahashi mailto:faithandbrave@gmail.com https://sites.google.com/site/faithandbrave/about/en