Operator Overloading with multiple return types

[drug]

16.03.2019 1:30, eXodiquas пишет:
> On Friday, 15 March 2019 at 21:46:50 UTC, Ali Çehreli wrote:
>> On 03/15/2019 02:43 PM, Sebastiaan Koppe wrote:
>>> On Friday, 15 March 2019 at 21:35:12 UTC, eXodiquas wrote:
>>>> Is there any way to achive this behaivour with D2?
>>>
>>> Yep. Just make the return type in the function declaration `auto`. 
>>> You are then free to return a different type in each static branch.
>>
>> Or use template constraints:
>>
>>
>> struct Vector {
>>   Vector opBinary(string op)(Vector rhs)
>>     if (op == "+") {
>>       return Vector();
>>     }
>>
>>   double opBinary(string op)(Vector rhs)
>>     if (op == "/") {
>>       return 0.5;
>>     }
>> }
>>
>> Ali
> 
> Thanks for the quick and simple answers, but I don't get this one. If I 
> do it that way the compiler doesn't know which function to call, or am I 
> doing something wrong?
> 
> Vector2 opBinary(string op)(Vector2 rhs) {
>          if (op == "+") {
>              return Vector2(this.x + rhs.x, this.y + rhs.y);
>          } else if (op == "-") {
>              return Vector2(this.x - rhs.x, this.y - rhs.y);
>          }
>      }
> 
>      float opBinary(string op)(Vector2 rhs) {
>          if (op == "*") {
>              return this.x * rhs.x + this.y * rhs.y;
>          }
>      }
> 
> This gives me the error:
> overloads (Vector2 rhs) and (Vector2 rhs) both match argument list for 
> opBinary
> 
> eXodiquas
You add wrong braces (`if` here is part of method signature not its body):
```
       Vector2 opBinary(string op)(Vector2 rhs) if (op == "+")
       {
           return Vector2(this.x + rhs.x, this.y + rhs.y);
       }

       Vector2 opBinary(string op)(Vector2 rhs) if (op == "-")
       {
           return Vector2(this.x - rhs.x, this.y - rhs.y);
       }

       float opBinary(string op)(Vector2 rhs) if (op == "*")
       {
           return this.x * rhs.x + this.y * rhs.y;
       }
```