Re: [boost] Re: [MPL] Type detection

From: Joel de Guzman (joel_at_[hidden])
Date: 2003-10-23 20:25:54

Brian McNamara <lorgon_at_[hidden]> wrote:
> I see now where I misunderstood.
> 
> On Fri, Oct 24, 2003 at 07:32:51AM +0800, Joel de Guzman wrote:
>> I posed 2 solutions:
>> 
>> 1) Have all iterators inherit from a base:
>>  (using CRTP: curriously recurring...)
>> 
>>     template <class I>
>>     inline typename mpl::deref<I>::type
>>     operator*(iterator_base<I> const&);
> 
> Somehow I missed that this (using the base class as a way to narrow the
> overload set) was one of the alternatives you were proposing...
> 
>> 2) Have an is_tuple_iterator<I> meta-function
>> 
>>     template <class I>
>>     inline typename lazy_enable_if<
>>         is_iterator<T>
>>       , mpl::deref<I>
>>     >::type
>>     operator*(I);
> 
> ... and I thought both of your proposed solutions were a variation of
> this (using some version of enable_if).  Now that I've gone back and
> re-read the whole thread again, I see what you were/are saying.
> 
> I definitely think #2 is the right way to go.
> 
> Thanks for clarifying!

Well, I was kinda hoping that you have a trick up your sleeve :->
If you can think of something better, I'm all ears.

Cheers,
-- 
Joel de Guzman
http://www.boost-consulting.com
http://spirit.sf.net