[boost] Re: Re: Re: Re: In-place construction for variant

From: Fernando Cacciola (fernando_cacciola_at_[hidden])
Date: 2003-10-29 23:43:08

"E. Gladyshev" <egladysh_at_[hidden]> escribió en el mensaje
news:20031030041316.23613.qmail_at_web40808.mail.yahoo.com...
>
> --- Fernando Cacciola <fernando_cacciola_at_[hidden]> wrote:
> [...]
> > > > > struct type
> > > > > {
> > > > >   //invariant is x + y = 10
> > > > >   int x;
> > > > >   int y;
> > > > >
> > > > >   void f( int n )
> > > > >   {
> > > > >      x = n;  //* invariant is broken
> > > > >      f1();  //* is this allowed?
> > > > >      y = 10-n;  //* invariant restored
> > > > >   }
> > > > >
> > > > The way I see it, if f1() is not public, then the above is most
likely
> > OK.
> > > > If is it public, then it is most likely not OK.
> > >
>
> [...]
>
> > Invariants are realted to design *contracts* and not all calls are
routing
> > contract messages. Implementation calls typically don't, and as you
pointed
> > out, outside calls might be also contract unrelated, thus the invariant
need
> > not hold during the call.
>
> You mentioned before:
> > > > If is it public, then it is most likely not OK.
>
> So "most likely" means "if the public methods contract related"...
> if f1() is contract unrelated, then it is Ok?
>
As a general guideline, yes, it's OK.

Fernando Cacciola
SciSoft