Re: [boost] [contract] first attempt to N3351 concepts

Subject: Re: [boost] [contract] first attempt to N3351 concepts
From: Lorenzo Caminiti (lorcaminiti_at_[hidden])
Date: 2012-10-10 04:37:48

On Wed, Oct 10, 2012 at 12:54 AM, Andrzej Krzemienski
<akrzemi1_at_[hidden]> wrote:
> 2012/10/9 Lorenzo Caminiti <lorcaminiti_at_[hidden]>
>
>> Hello all,
>>
>> I made a first attempt to sketch how N3351-like concepts will look
>> into Boost.Contract (just for the find algorithm and its concepts for
>> now):
>>
>>
>> http://contractpp.svn.sourceforge.net/viewvc/contractpp/branches/stl_concept/doc/html/n3351.html
>>
>> This code doesn't compile quite yet but I played with its bits and
>> pieces enough to conclude that it should be implementable as listed.
>> It will take quite a bit of time and effort to implement this...
>> Please tell me what you think now so I don't waste time implementing
>> this design if it has issues.
>>
>
> N3351 allows specifying sort-of postconditions with axioms, like:
>
>   axiom Clearing(Vec vec) {
>     vec.clear(), vec.empty();
>   }

Yes, this won't work.

> This uses the comma operator in a tricky way to perform two instructions. I
> wonder if this will interfere with the way the comma is interpreted in
> Boost.Contract. Is it possible in your design to type:
>
>   axiom(
>     (vec.clear(), vec.empty())
>   )

Yes, this should work.

But then again, given that we are only checking axioms syntax and we
are not running them, it won't make any difference in practice...

Thanks,
--Lorenzo