Operator overloading

[Andrei Alexandrescu]

John Reimer wrote:
> Hello Andrei,
> 
>> The Anh Tran wrote:
>>
>>> Andrei Alexandrescu wrote:
>>>
>>>>> auto op(++)(); // bar++
>>>>> auto op(++)(int); // ++bar
>>>> Hey, wasn't the implementation of the postincrement operator through
>>>> an overload a rather untasty hack?
>>>>
>>>> Aside for a minor change in notation, there's no improvement. We're
>>>> looking for much more broad improvements, such as offering the
>>>> ability to overload several operators with only one function.
>>>>
>>>> Andrei
>>>>
>>> How about this:
>>>
>>> Unary op: ++f, ~f, ~f, +f, -f, *f
>>> auto operator(++, --, ~, !, +, -, *)()
>>> {
>>> // posfix is provided by compiler
>>> // and is only used for: foo++ foo--
>>> static if (posfix)
>>> return op(this.value);
>>> else ...
>>> }
>>> Binary op: equality comparison f1 <= f2
>>> bool operator(<, >, <=, >=, ==, !=)(Foo foo)
>>> {
>>> return op(this.value, foo.value);
>>> }
>>> For un-order object, he/she just list 'correct' operator(s) in op()
>>> list. Ex: bool operator(!=, ==)(Foo foo) {}
>>>
>> Why invent new syntax when compile-time strings are already there?
>>
>> auto operator(string op)() if (op == "++" || op == "--")
>> {
>> return mixin(op ~ "this.value");
>> }
>> etc. That, of course, is orthogonal to the semantic equivalences
>> suggested by Don and does not solve fusion.
>>
>> Andrei
>>
> 
> 
> Once again, I'm no expert in this matter, but the compiler-time strings 
> idea looks like a great solution for this.  Was this brought up before? 
> ...because that was kind of what I was thinking when you mentioned a new 
> operator overloading syntax for D.

Only in private conversation between Walter and me. But anyway, let's 
not forget we need to address fusion as well.

Andrei