*final* class member (D2)

[Denton Cockburn]

On Wed, 13 Feb 2008 14:33:33 -0500, Steven Schveighoffer wrote:

> "Denton Cockburn" wrote
>> How do I do this?  I'm trying to create a class member here that needs to
>> be initialized in the constructor, but cannot be changed later.
>>
>> class A
>> {
>>   (const doesn't work) real delegate() dg; // this is that
>>   function;
>>
>>   this(real delegate() dg) { this.dg = dg; }
>> }
>>
>> class B
>> {
>>   real foo() { return 3.5; }
>> }
>>
>> class C
>> {
>>   real foo() { return 4.5; }
>> }
>>
>> void main()
>> {
>>   auto b = new B;
>>   auto a = new A(&b.foo);
>>   auto c = new C;
>>   a.fitness = &c.foo; // I want this to be an error
>> }
> 
> um... did you try encapsulation?
> 
> class A
> {
>    private real delegate() _dg;
> 
>    public real dg()
>    {
>       return _dg();
>    }
> 
>    this(real delegate() dg) { this._dg = dg; }
> }
> 
> -Steve

This was the workaround I used as well.
I don't like it because of the extra level of indirection (I end up
calling 2 functions instead of 1).  I don't consider this very efficient
or convenient.