Concepts vs template constraints - the practical approach

Norbert Nemec Norbert at Nemec-online.de
Sun Nov 20 22:42:10 PST 2011


On 20.11.2011 21:07, Andrei Alexandrescu wrote:
> On 11/20/11 10:41 AM, Norbert Nemec wrote:
> [snip]
>
> Why not follow the patter of isXxx in the standard library?
>
> Andrei

Actually, that was my starting point. However, this approach does not 
scale up:

A concept typically is a collection of requirements that have to be met 
individually. A huge boolean statement inside an assertion does not give 
any clue as to which part of it failed.

The isXxx approach works fine for the template constraint itself, but to 
assert that a given type meets all requirements of a concept, it is not 
very usable at all.


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