Re: [boost] [Iterator][MultiIndex]iterator-specificpartition_point-relatedfunctions

Subject: Re: [boost] [Iterator][MultiIndex]iterator-specificpartition_point-relatedfunctions
From: David Abrahams (dave_at_[hidden])
Date: 2008-12-27 18:45:24

on Sat Dec 27 2008, Arno Schödl <aschoedl-AT-think-cell.com> wrote:

>>>> Furthermore, if you publish the type of the function object used, people
>>>> can still customize all of those individual variants if they're crazy
>>>> enough to want to do that.
>>>
>>> I don't understand what you mean.
>
>>The customizer simply writes a partition_point overload where the
>>function object type is specific, e.g. something like
>>binder2nd<std::less<T>, T> (I forget the real signatures)
>
> Ah, ok. We may want to turn the bind function objects into C++0x lambdas later. I am
> not sure you can overload on lambda types.
>
>>> O.k., I am happy we finally have agreement:-) I will send out the new version. Do
> you
>>> want to include it into Boost.Iterator (my preference), or as a separate library?
>>
>>I'm sorry, but what component(s) are you proposing should be included
>>into Boost.Iterator?  Not the default partition_point,
>>boost::lower_bound, et. al.?
>
> Yes, that was the idea, to have all tools to implement a new iterator
> in one place. 

You *generally* don't need to customize partition_point in order to
implement a new iterator.

> If
> you don't like that, how do you want to do it?  Separate library "partition_point"
> with
>
> - algorithms.hpp for default partition_point and lower_bound et. al., 
>
> and 
>
> - transform_iterator.hpp
> - ...
>
> for the various partition_point overloads? 

Something like that seems likely.  I'm still having trouble
understanding how you can implement a specialization for
transform_iterator without knowing more than actually possible about the
semantics of the transformation function.

> Or only have the default implementation in a separate library and implement the
> partition_point overloads in Boost.Iterator/Boost.MultiIndexContainer's
> iterator-specific header files, such as transform_iterator.hpp?

I'm getting confused, sorry.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com