Operators overloading in D2 again

[Ali Çehreli]

Dan wrote:
> Hi everyone,
> 
> is there anyway to do this with operators overloading? :
> 
> 
> class Tester
> {
> 	double x = 0.0;
> 
> 	double opBinary(string op:"+")(double value)
> 	{
> 		return x+value;
> 	}
> 
> 	Tester opBinary(string op:"+")(Tester other)
> 	{
> 		Tester ret;
> 		ret.x += other.x;
> 		return ret;
> 	}
> }
> 
> int main(char[][] args)
> {
> 	Tester t1 = new Tester;
> 	Tester t2 = new Tester;
> 
> 	t1.x = 1.0;
> 	t2.x = 2.0;
> 
> 	Tester t3;
> 	t3 = t1+t2;
> 	assert (t3.x = 3.0);
> 
>         return 0;
> }
> 
> 
> Thanks,
>      Dan

Functions can not be overloaded by return type alone; so I took the one 
that returned double out.

We are dealing with a Tester class, and it makes sense to me to stay in 
this type. When necessary, we can provide a conversion function that 
returns a double value.

I've corrected a couple of errors, introduced a constructor, and came up 
with this:

class Tester
{
     double x = 0.0;

     this(double x)
     {
         this.x = x;
     }

     Tester opBinary(string op:"+")(const Tester other) const
     {
         return new Tester(x + other.x);
     }
}

int main(char[][] args)
{
     Tester t1 = new Tester(1.0);
     Tester t2 = new Tester(2.0);

     Tester t3 = t1 + t2;
     assert (t3.x == 3.0);

     return 0;
}

Ali