Immutable objects and constructor ?

[Mike Parker via Digitalmars-d-learn]

On Friday, 20 May 2016 at 20:30:22 UTC, chmike wrote:

>
> I'm a bit surprized that the language doesn't support this. We 
> have immutable strings that can be assigned to different 
> variables. Why couldn't we do the same with objects ?

Consider this:

immutable(char)[] str;

Here, the array elements of str are immutable, i.e. you cannot do 
this:

str[0] = 's'

However, the array reference itself is mutable, so you can freely 
assign array references around. This is what string is aliased to.

To prevent the array reference from being assigned:

immutable(char[]) str;

Now trying to assign another string to str will produce a 
compiler error.

With arrays and pointers, we distinguish between the data and the 
reference. With classes, we do not; there is only the reference.