On 14/08/10 05:55, Walter Bright wrote:
Graham St Jack wrote:
For me, the key problem is that a class object reference has the same
const/immutable/shared attribute as the object on the heap that it
refers to. This is sometimes what you need, but more often you want a
non-shared, mutable reference to a const/immutable/shared object.
I struggled with this for a long while before I eventually came to the
conclusion that I was thinking about class objects as a reference and
the instance, and that those two were separable concepts. They are not.
A reference type is implicitly treated like a value type as far as
accessing its members go. Trying to separate out the two is a
fundamental misunderstanding of what reference types are all about.
Semantically, they are much more than just a pointer to the instance.
You can achieve this with pointers for arrays, structs and primitive
types, but not with classes because a class pointer is just a pointer
to a reference.
The way to do it with class is take a pointer to the class:
class C { ... }
const(C)*[]; // array of pointers to const classes
just like you'd do with a struct.
I get it - I think. I will give this a try and see how it works in practice.
--
Graham St Jack
