Re: where exactly c++,c fail and Ada gets thru'

["Martin Krischik" <krischik@users.sourceforge.net>]

REH wrote:
> Martin Krischik wrote:
> > Maciej Sobczak wrote:
> >
> > > Yes, classes are used to define new types. Is there any problem with
> > > this? It is also necessary in Ada if we want to do just a bit more of
> > > what is provided by type and subtype constructs.
> >
> > Say:
> >
> > type Y_Type is range 1 .. 10;
> > subtype X_Type is new x range 1 .. 5;
> >
> > function F (X: X_Type) return Y_Type is
> > begin
> >   return X + 3;
> > end F
> >
> > Now I would expect that an Ada compiler will not insert any runtime checks
> > as X + 3 is allways in the range of Y_Type. However:
> >
> > function G (X: X_Type) return Y_Type is
> > begin
> >   return X + 7;
> > end G;
> >
> > may well be outside the range of Y_Type and if so CONSTRAINT_ERROR will be
> > raised.
> >
> > Now say we have a suitable C++ range template:
> >
> > typedef range<int, 1, 10> Y_Type;
> > typedef range<Y_Type, 1, 5> X_Type;
> >
> > Y_Type F (X_Type X)
> >   {
> >   return X + 3;
> >   }
> >
> > Y_Type G (X_Type X)
> >   {
> >   return X + 7;
> >   }
> >
> > Now anyone up to the challenge to define:
> >
> > template <typename Base_Type, Base_Type First, Base_Type Last>
> > range::operator = (Base_Type right)
> >
> > template <typename Base_Type, Base_Type First, Base_Type Last>
> > range::operator + (Base_Type right)
> >
> > template <typename Base_Type, Base_Type First, Base_Type Last>
> > range::range (Base_Type right)
> >
> > in such a way that it works like Ada - inclusive the *realistic* change that
> > the compiler will optimize away the range check in F ().
>
> I have done this.

I had a look. Looks impressive with all those includes. Looks like one
of thoses templates I never want to debug thrue.

But don't expect me to have found that magic static analysis something
trick. So:

How exactly did you do it?

Martin