Instance variables with @ (was: Re: why ; ?)

[Nick Sabalausky]

"Michael Neumann" <mneumann at ntecs.de> wrote in message 
news:g01mtk$1nvj$1 at digitalmars.com...
> Nick Sabalausky wrote:
> > // Note: untested
> > class A {
> >   int i=0;
> >
> >   void foo() {
> >     // Accidentially clobbers "this.i" aka "@i"
> >     for(i=0; i<77; i++)
> >       {/* Do stuff */}
> >   }
> >
> >   invariant() {
> >     assert(this.i==0); // Fails after foo() is called
> >   }
> > }
> >
> > I still like the @ thing, though.
>
> Very good example!
>
> A solution could be to force the programmer to use the "this." notation
> or at least issuing a compiler warning if not done.  The latter could be
> implemented in the compiler without any changes to the syntax/language.
>

I had been thinking of this feature as a pipe dream (at least for D), just 
because it would mean changing the language to always require "this." or 
"@". Implimenting it as an optional warning hadn't occurred to me. That 
makes it sound much more possible. Good call on that (no pun intended).

> The next step would be to have "@" as a synonym for "this.", as typing
> "this." all the time is either annoying and as such is ignored or leads
> to less readable code (IMHO).
>

Agreed. I would love to see this actually happen. Although, I do wonder if 
maybe we're chasing too rare of a problem to bother, or maybe it would 
segregate the D scene into "@D" people and "raw D" people (I hope not, 
'cause I do like it).

Any comments from Walter? I'm curious what his take is on the original 
problem.