Re: [boost] [Review] GGL review starts today, November 5th

Subject: Re: [boost] [Review] GGL review starts today, November 5th
From: Stefan Strasser (strasser_at_[hidden])
Date: 2009-11-11 15:56:51

Hi,

this is not a review, and there won't be one because I'm not "knowledgable 
about the problem domain", but some some quick comments about the traits 
classes after reading the design rationale and looking at some code.

 - first of all, I'm curious why you chose to use one traits class for 
each "agnosticism". this differs from the standard library, so I guess there 
is a specific reason for it?
e.g. std::iterator_traits defines iterator_category, pointer, reference and so 
on. the equivalent in a GGI Point concept is tag, coordinate, dimension..., 
which are defined in 5 different traits classes.

 - is there a default implementation of the traits classes? I haven't found 
one in code/coordinate_dimension.
this would simplify writing concept models in many cases, especially with 5 
different traits for a Point.

e.g., the iterator_traits default implementation looks like this:

template<typename _Iterator>
    struct iterator_traits
    {
      typedef typename _Iterator::iterator_category iterator_category;
      typedef typename _Iterator::value_type        value_type;
      typedef typename _Iterator::difference_type   difference_type;
      typedef typename _Iterator::pointer           pointer;
      typedef typename _Iterator::reference         reference;
    };

 - on a minor note, tag<> seems a little non-descriptive, compared to 
iterator_category in the STL.
Boost.Iostreams and Boost.PropertyMap both use "category", which might also be 
suitable for GGI, since it has its own namespace and there are no other 
categories I assume.