On Sat, 07 Mar 2009 23:40:52 -0800, Walter Bright wrote:
> I'm still not understanding you, because this is a contrived example
> that I cannot see the point of nor can I see where it would be
> legitimately used.
I can see Burton's concern, and I'm very surprised that the compiler allows
this to happen. Here is a slightly more explicit version of Burton's code.
import std.stdio;
void main()
{
int [] a = new int [1];
a [0] = 1;
invariant (int) [] b = cast (invariant (int) []) a;
writef ("a=%s b=%s\n", a [0], b[0]);
a [0] += b [0];
writef ("a=%s b=%s\n", a [0], b[0]);
a [0] += b [0];
writef ("a=%s b=%s\n", a [0], b[0]);
}
The problem is that we have declared 'b' as invariant, but the program is
allowed to change it. That is the issue.
--
Derek Parnell
Melbourne, Australia
skype: derek.j.parnell
