overloading InExpression

[Ali Çehreli via Digitalmars-d-learn]

On 07/02/2014 07:35 AM, Vlad Levenfeld wrote:
> On Wednesday, 2 July 2014 at 14:14:57 UTC, Dicebot wrote:
>> struct S
>> {
>>     int opIn_r(int key)
>>     {
>>         return key*2;
>>     }
>> }
>>
>> void main()
>> {
>>     assert((42 in S.init) == 84);
>> }
>
> Thanks! I wonder, why the _r

I think it is the old syntax, meaning "this is the overload for when an 
S object is on the right-hand side".

 > and lack of documentation?

It appears in the binary operator table:

   http://dlang.org/operatoroverloading.html#Binary

Also see the section 'Inclusion query by opBinaryRight!"in"' here:

   http://ddili.org/ders/d.en/operator_overloading.html

Ali