constness for arrays

[Andrew Fedoniouk]

"Ben Phillips" <Ben_member at pathlink.com> wrote in message 
news:e9rc1u$1g71$1 at digitaldaemon.com...
> >
>>operator "="  IS really necessary.  As there is no method in D
>>currently to guard assignment to variable (memory location).
>>Again without it good chunk of RAII methods and smart pointers
>>are not implementable in D.
>>
>
> It is impossible to allow operator "=" to be overloaded without totally 
> killing
> the way D works because D uses references.
> Example:
> ClassA a = new ClassA();
> ClassA b = a; // b now refers to a
> b.mutate(); // both 'b' and 'a' are changed since they refer to the same 
> object
>

I think that operator= shall be available only for structs and probably 
other value types.
So it will be no conflict with current situation.

> What is possible is to define a new operator (such as ":=") that means 
> copy
> assignment, but I don't see how this differs from creating a method that 
> does
> the same thing.

method is not an option at all.
operator= is a guard of memory loacation and method, well, is method.

struct guard {
   int v;
   void opAssign(int nv) {  alarm("value 'v' is about to change"); v = 
v;  }
}

guard gv;
gv = 12;

As you may see operator= guards memory location allowing you to intercept
all assignments into the variable. Too many things (RAII, smart pointers) 
were built
around this in C++.

Method of the struct will not help you here in principle.

Andrew Fedoniouk.
http://terrainformatica.com