DIP80: phobos additions

[Tofu Ninja via Digitalmars-d]

On Wednesday, 24 June 2015 at 19:04:38 UTC, Wyatt wrote:
> On Wednesday, 17 June 2015 at 09:28:00 UTC, Tofu Ninja wrote:
>>
>> I actually thought about it more, and D does have a bunch of 
>> binary operators that no ones uses. You can make all sorts of 
>> weird operators like +*, *~, +++, ---, *--, /++, ~~, ~-, -~,
>> >>>--, &++, ^^+, in++, |-, %~, ect...
>>
>> void main(string[] args){
>> 	test a;
>> 	test b;
>> 	a +* b;
>> }
>> struct test{
>> 	private struct testAlpha{
>> 		test payload;
>> 	}
>> 	testAlpha opUnary(string s : "*")(){
>> 		return testAlpha(this);
>> 	}
>> 	void opBinary(string op : "+")(test rhs){
>> 		writeln("+");
>> 	}
>> 	void opBinary(string op : "+")(testAlpha rhs){
>> 		writeln("+*");
>> 	}
>> }
>
> Oh right, meant to respond to this.  I'll admit it took me a 
> few to really get why that works-- it's fairly clever and 
> moderately terrifying.  (I showed it to a friend and he opined 
> it may violate the grammar.)
>
> But playing with it a bit...well, it's very cumbersome having 
> to do these overload gymnastics.  It eats away at your opUnary 
> space because of the need for private proxy types, and each one 
> needs an opBinary defined to support  it explicitly.  It also 
> means you can't make overloads for mismatched types or builtin 
> types (at least, I couldn't figure out how in the few minutes I 
> spent poking it over lunch).
>
> -Wyatt

I am thinking of writing a mixin that will set up the proxy for 
you so that you can just write.

struct test
{
      mixin binOpProxy("*");
      void opBinary(string op : "+*", T)(T rhs){
           writeln("+*");
      }
}

The hard part will be to get it to work with arbitrarily long 
unary proxies. Eg:
mixin binOpProxy("~-~");
void opBinary(string op : "+~-~", T)(T rhs){
      writeln("+~-~");
}