Burton Radons wrote:
Walter Bright Wrote:
Burton Radons wrote:
This wouldn't be too bad because const is worthless when
optimising, but if invariant is going to be given any weight then
we must never cause data to be casted to invariant unless if it's
actually invariant data. So, the sensible default is "const
(char) []" for strings, a selection of aliases in object.d for
the others, and safe casting templates in object.d.
What I interpret from this is that you see strings as fundamentally
mutable character arrays, and sometimes in special cases you can
make them immutable. I propose turning that view on its head -
regard strings as fundamentally immutable, and having a mutable
char array is a rare thing that only appears in isolated places in
the program.
No, I don't. You are misunderstanding me, and I'm not sure why or
how.
I guess I just cannot figure out where you're coming from.
Here's a (contrived) example of where my concern may come into
play:
int [] a = new int [1];
a [0] = 1;
auto b = cast (invariant (int) []) a;
a [0] += b [0]; a [0] += b [0]; writef ("%s\n", a [0]); // Normal
result: 4. // Optimiser which assumes invariant data can't change: 3
Yes, the code is an abuse of the const system. THAT'S EXACTLY MY
POINT. Casting mutable data to invariant leads to situations like
these. Only data which will never change can be made invariant.
Putting "alias invariant (char) [] string" in object.d induces these
situations and makes it seem like it's a good idea.
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.
