Re: [boost] [contract] concepts: pseudo-signatures vs. usage patterns

Subject: Re: [boost] [contract] concepts: pseudo-signatures vs. usage patterns
From: Andrzej Krzemienski (akrzemi1_at_[hidden])
Date: 2012-10-14 15:44:18

2012/10/14 Dave Abrahams <dave_at_[hidden]>

>
> on Sun Oct 14 2012, Andrzej Krzemienski <akrzemi1-AT-gmail.com> wrote:
>
>
> > Can you help me understand one thing about pseudo-signatures? If I have
> the
> > following concept:
> >
> >   concept MyIter<typename It>
> >   {
> >     It& operator++(It&);
> >     bool It::is_valid();
> >   }
> >
> > Does this say preincrement returns exactly reference to It or only
> > something convertible to It?
>
> It says that
>
> * the preincrement of a /model/ of MyIter must return something
>   convertible to It&
>
> * WHen a function constrained to using the MyIter concept preincrements
>   an instance of MyIter, it sees exactly It& returned, regardless of
>   what is actually returned by the model's preincrement operation.
>
>
Thanks for this explanation. Now I feel I finally understood the
pseudo-signatures.

Regards,
&rzej