Re: [boost] [Concepts] Definition. Was [GSoC] [Boost.Hana] Formal review request

5 Aug 2014


      On 2014-08-05 12:14, Mostafa wrote:
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On Tue, 05 Aug 2014 01:59:34 -0700, Roland Bock  wrote:
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On 2014-08-05 10:30, Krzysztof Czainski wrote:
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2014-08-05 6:33 GMT+02:00 Michael Shepanski :
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On 5/08/2014 1:39 AM, Roland Bock wrote:
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On 2014-08-04 13:32, Mostafa wrote:
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Concepts are sets of types
I think you are mistaken. A concept is a set of requirements,
I am under a New Year's resolution not to start philosophical
arguments,
but this one has already begun, so ...
Please don't forget, that not all requirements can be checked at
compile
time. For example: TotallyOrdered. Just by checking, that an expression
(a
So, while I think it doesn't matter, whether we view concepts as
sets of
types or requirements
Well, if you consider TotallyOrdered a concept, then by this reasoning,
it cannot be a set of types. But it could be a set of requirements :-)
Yes it can. TotallyOrdered := { T | if a,b,c are objects of T then ... }
As Kris pointed out: Whether an object is TotallyOrdered or not cannot
be checked at compile time because it does not depend on the type alone,
it also depends on runtime information. Hence, not a set of types.

Best,

Roland