Re: [boost] [Review] Boost.Contract Review Period Extended

Subject: Re: [boost] [Review] Boost.Contract Review Period Extended
From: ecyrbe (ecyrbe_at_[hidden])
Date: 2012-09-06 12:57:18

2012/9/6 Lorenzo Caminiti <lorcaminiti_at_[hidden]>

> On Thu, Sep 6, 2012 at 7:05 AM, ecyrbe <ecyrbe_at_[hidden]> wrote:
> > I vote  NO for the inclusion of the contract library in Boost.
>
> Thanks a lot for submitting a review!
>
>

I think my tone could seem a litle rude. I forgot to congratulate you for
the long a hard work you have done on this library.

> > I do agree that the work done is really interresting, but i don't think
> > that using MACROS are the way to add this functionnality.
>
> Sure this'd be ideal but... do you have any suggestion on how to
> implement Contract Programming within C++ without using macro? I
> thought about this problem a lot (that of "not using macros" was even
> an original goal when I started creating the library 4+ years ago) but
> I had to conclude it's impossible... For example (and there are more
> examples like this) how would you implement the following CP
> requirements without macros?
> 1. If a function is not public, don't check class invariants.
> 2. Subcontracting.
>
>
I would like to comment on this. I know that making a Eiffel like
integrated contract programming in c++ in not feasible.
But i think that an original one, maybe based on functors could be possible
(may be i'm totally wrong).

something declared like a boost::function<Signature>, but using something
like :

   boost::contract<Signature> push_back;

and has to be initialized like this :

   push_back(precondition_functor,
real_push_back_functor,postcondition_functor);

and if any invariant is declared :

   push_back(precondition_functor,
real_push_back_method,postcondition_functor, invariant_functor);

I know that it's not easy to implement functors in c++03 , but in c++11
with lambdas, you could initialize this really easily, and still have a
nice library.
For c++03, you still could provide a macro frontend to allow users to
implement this easily, but having a more native way to do it in c++11 would
be awesome.

What i want to say, is that, i would have said YES to this macro frontend
if a nice c++11 compliant backend was exposed to those that don't want to
use macros.

These are only thoughts.

Thanks for reading.