D1 operator overloads have been deprecated.

[Bert]

On Friday, 12 July 2019 at 15:07:11 UTC, Timon Gehr wrote:
> On 12.07.19 15:42, Bert wrote:
>> 
>> um, the OP said "works with virtual functions/inheritance". 
>> When are people going to learn that aliases are not virtual 
>> and have nothing to do with preserving inheritance structure?
>> 
>> 
>> import std.stdio;
>> 
>> class X
>> {
>> }
>> class C : X{
>>      int x;
>>      this(int x){ this.x=x; }
>>      C opAddImpl(C rhs){
>>          return new C(x+rhs.x);
>>      }
>>      alias opBinary(string op:"+")=opAddImpl;
>> }
>> void main(){
>>      X a=new C(1),b=new C(2);
>>      writeln((a+b).x);
>> }
>> 
>> fails.
>
> Please do enlighten us how you would make that work with D1 
> operators.

I said nothing about getting it to work. It works

import std.stdio;

abstract class X
{
     //abstract X opNeg(); // D1
     abstract X opNegImpl(); // D2
     alias opUnary(string op : "-") = opNegImpl; // D2
}

class C : X
{
     int x;
     this(int x) { this.x = x; }
     //override C opNeg(){ return new C(-this.x); } D1
     override C opNegImpl() { return new C(-x); }

}

void main()
{
     X a = new C(1), b = new C(2);
     writeln((cast(C)(-b)).x);
}

There is nothing wrong with D1 operators! Unless there is a 
deeper problem besides just freeing names, what is being done is 
a whole lot of old D code will be broke simply to free opXXX 
id's... This type of thing is called *making a small problem much 
bigger*.


Maybe the better way would be to convert the D1 op names to

opD1XXX

then at least a simple search and replace can solve 99% of the 
problems... of course, there is no real problem because someone 
will come along and complain that the id name space is polluted 
with opD1XXX's and must be removed... at some point someone has 
to stand up and say "It's not an issue but breaking hundreds of 
thousands of lines of library code is!".

If you think opD1XXX is too common, then 
_op_D1_OLD_OPERATOR_NAME__XXX...

It's irrelevant, but deprecating something just for the hell of 
it is wrong and that is what *seems* to be done here(I'm going 
off what J.D. said about there being two ways to do the same way, 
the old D1 way with fixed opXXX and the new way with opXXX 
templates, which, are in fact essentially identical semantically 
with a slight syntactical difference... sorta like {} VS BEGIN 
and END.)