Re: [boost] Re: is_base_and_derived

From: Rene Rivera (grafik.list_at_[hidden])
Date: 2003-10-27 10:39:22

[2003-10-27] Brian McNamara wrote:

>On Mon, Oct 27, 2003 at 07:33:16AM -0700, Dave Gomboc wrote:
>> > Actually I'd prefer
>> > 
>> >    is_proper_subtype< D, B >
>> >    is_subtype< D, B >      
>> > 
>> > but you have to be careful that you reverse the argument 
>> > order when changing your old code over from is_base_and_derived.
>> 
>> Many different forms specifying one but not the other (ancestor,
>> descendent, superclass, subclass, etc.) were rejected due to the ease
>> with which a developer could nonetheless misinterpret which argument is
>> supposed to go first.  (You could trawl the archives for this.)
>
>I can definitely imagine this.  I was thinking the same thing and was
>going to cite the 'argument order clarity' as one of the advantages to
>is_base_and_derived, until I had the epiphany that
>
>   is_subtype< D, B >      
>
>is just how C++ forces us to spell
>
>   D::is_subtype<B>
>
>non-intrusively.  
>
>
>Oh, which means I actually prefer the name "is_subtype_of".
>
>
>It's totally analogous to the non-meta case, e.g.
>
>   contains( aRegion, aPoint )
>
>means
>
>   aRegion.contains( aPoint )

Doesn't that then argue for something like:

    is_<D>::subtype_of<B>

??

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