preparing for const, final, and invariant

[Derek Parnell]

On Sun, 20 May 2007 20:10:44 -0700, Walter Bright wrote:

> Regan Heath wrote:
>> Why not make this implicit 'in' parameter 'scope const final' avoiding the need to explicity say 'in' everywhere?
> 
> It's a good idea, but then there needs to be some way to pass a mutable 
> reference. Such as:
> 
> class C { int x; }
> void foo(C c)
> {
>      c.x = 3;
> }
> 
> That doesn't work if 'const' is the default. Using out or inout doesn't 
> work either, as those have slightly different semantics (an extra level 
> of indirection).

What about 'const ref' meaning that a reference is being passed and that
reference is constant but not the data being referred to...?

 class C { int x; }
 void foo(const ref C c)
 {
      c.x = 3; // okay
      c = new C; // fail
 }

I know I wouldn't mind changing my code to do this. It is just a lot safer
and I'd rather "get it right" now than some years down the road with D.

-- 
Derek
(skype: derek.j.parnell)
Melbourne, Australia
"Justice for David Hicks!"
21/05/2007 1:53:21 PM