Inherited const when you need to mutate

[Andrei Alexandrescu]

On 7/10/12 5:19 PM, H. S. Teoh wrote:
> Isn't there something we can do to improve this situation?

There is, only thing is there's no easy way (without adding some amount 
of complication to the language).

Generally const(T) is a supertype of T and immutable(T), meaning it 
could originate from either.

There is value in immutable objects that has been well discussed, which 
is incompatible with logical constness. We can change the language such 
as: a given type X has the option to declare "I want logical const and 
for that I'm giving up the possibility of creating immutable(X)". That 
keeps things proper for everybody - immutable still has the strong 
properties we know and love, and such types can actually use logical const.

A number of refinements are as always possible.

I'm not sure if I was very clear. In brief, logical constness breaks 
things only if the original object was immutable.


Andrei