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

From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2008-04-12 12:58:43

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<bool(int)> for the predicate type.

In Christ,
Steven Watanabe