Bill Baxter wrote:
On Fri, Jul 24, 2009 at 2:19 PM, Andrei
Alexandrescu<[email protected]> wrote:
Jarrett Billingsley wrote:
On Thu, Jul 23, 2009 at 5:56 PM, Michiel
Helvensteijn<[email protected]> wrote:
Eldar Insafutdinov wrote:
from your post:
property int length {
get() { return this.len; }
set(newLen) { this.len = newLen; }
void opIncrement() { this.len++; }
}
I don't think that's flexible to overload every operator to get the best
performance. As Walter likes to say the best way should be the most
obvious. Besides we forgot that D2 allows to return references, which
eliminates the issue.
If your property really just hides a private member variable, it was
probably for encapsulation purposes or because you want redundant actions
to be taken for every access. If you return a reference, you give
unlimited
and unrestricted access to that variable with only one call, and you
might
as well not have used a property at all.
If your property is derived -- that is, if it doesn't directly mirror a
variable --, there is no reference to return.
Besides, in D, you can probably use mixins to copy the entire interface
of a
type into the property without code duplication.
You're suggesting adding something like 25 operator overloads to every
property. Can you say "code bloat"?
Why not just use the following solution, which has been proposed
God-knows-how-many-times and already has precedence in other languages
(like C#)?
obj.prop op= value;
Simply becomes:
obj.prop.set(obj.prop.get op value);
I think this would be inefficient in many cases.
That is true but I also think:
* probably that is the best that can be achieved automatically.
* if better can be achieved automatically then the compiler can just
do that under the hood. No user code needs to change.
* set(get op value) probably won't be inefficient in some cases.
* having a op= b work automatically in an inefficient way is better
than forcing the users of the code to make the same ineffecient
transformation in their code manually (which is the status quo of
property syntax in D).
So I think how to make a op= b whizzy fast can be decided later. And
for now set(get op value) is good enough.
Ok, I got convinced.
Andrei
