Re: [boost] for_each abstraction

Subject: Re: [boost] for_each abstraction
From: Jeffrey Lee Hellrung, Jr. (jhellrung_at_[hidden])
Date: 2010-11-18 03:53:03

On 11/17/2010 1:50 PM, Eric Niebler wrote:
> On 11/17/2010 4:24 PM, joel falcou wrote:
>> Binding algorithm to container type lessen genericity of code.
>
> ... but is sometimes done in practice when the generic framework doesn't
> provide the concepts for optimal implementations; e.g.
> std::map::lower_bound. In the STL, that would be the case with for_each
> over segmented sequences. A better solution, however, would be to define
> a concept for segmented iterators and write a generic segmented for_each
> algorithm.

Right.  I almost read this as you suggesting to use segmented iterators 
for the OP's problem, but I don't think that's what you're suggesting.

The OP's original problem (as I understand it) was to provide a generic 
framework to use thrust::for_each when working with thrust::vector's, 
boost::fusion::for_each when working with Boost.Fusion sequences, and 
std::for_each when using any STL-compatible range (the default, 
basically).  Indeed, seems like this would just extend the idea of 
differentiating whether to dispatch to a std::for_each or a segmented 
for_each.  I only meant to suggest that one would have to somehow tie 
the sequence to a particular iteration mechanism (i.e., a for_each 
implementation).  The use of member function notation was a poor choice 
which kicked up more dust than I thought :/

- Jeff