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

Subject: Re: [boost] [contract] first attempt to N3351 concepts
From: Andrzej Krzemienski (akrzemi1_at_[hidden])
Date: 2012-10-10 03:54:55

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();
  }

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())
  )

?