Const Ideas

[Craig Black]

"Janice Caron" <caron800 at googlemail.com> wrote in message 
news:mailman.201.1196446640.2338.digitalmars-d at puremagic.com...
> On 11/30/07, Craig Black <cblack at ara.com> wrote:
>> Janice proposed an idea
>> for constifying instance member functions using const(this).
>
> That actually wasn't me. I like the idea (a lot), but I can't claim
> credit for inventing it.
>
> I did come up with the idea of extending it to const(identifier) though.
>
>
>> If we did this, I would suggest getting rid of the postfix syntax.
>
> I would certainly agree with that!
>
>
>> const X x;  // The data is const, the reference is mutable
>
> The problem I have with this is that I believe X should mean the same
> as (X). So if you accept that, const X x; must mean the same thing as
> const(X) x; And if you believe that const(...) has to mean "everything
> inside the brackets is const" (which is what I believe) then you have
> to conclude that const X x must mean "x is completely and absolutely
> const, and nothing about it is mutable". That's actually what it means
> right now (so long as you omit the brackets). That's why I argue that
> you need something else - something /outside the brackets/ - to mean
> "let the reference be mutable". (And obviously, that mechanism should
> only be available for reference types).

I see the dilemma.  So the probem with using const(ref) is that there would 
be no way to say that the data is const but the reference is mutable.  This 
is also a limitation of the current implementation is it not?