Re: [Boost-users] Hide the predicate type of a filter_iterator?

12 Apr 2008


      AMDG

Jean-Pierre Bergamin wrote:
...
Hello everyone
Imagine a class "numbers" that contains some values and methods like 
getEvenValues(), getOddValues(), getValuesLarger100() etc. Those methods 
return an iterator range of filter_iterators. In the the code I posted 
below, I'd have to define a different iterator_range of filter_iterator 
types for all the different methods (numbers::EvenFilterRange, 
numbers::OddFilterRange etc.). Is there some way to "hide" the type of 
the predicate used in a filter_iterator, so that it would be possible to 
have a generic "NumberRange" type for the return values of all methods? 
Something like:
class numbers {
    typedef NumberRange ????;
    NumberRange getEvenValues() const;
    NumberRange getOddValues() const;
    NumberRange getValuesLarger100() const;
}
Try using boost::function for the predicate type.

In Christ,
Steven Watanabe