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digitalmars.D.learn - opEquals when your type occurs on the right hand side of an equality

reply NonNull <non-null use.startmail.com> writes:
I am creating a specialized bit pattern (secretly represented as 
a uint) as a struct S, but want to avoid `alias this` to maintain 
encapsulation excepting where I overtly say. Specifically, I want 
to avoid making arithmetic and inequalities available for S.

I have written opEquals to compare an S to a uint.

How do I write code to compare a uint to an S?
Jul 31 2019
parent =?UTF-8?Q?Ali_=c3=87ehreli?= <acehreli yahoo.com> writes:
On 07/31/2019 01:03 PM, NonNull wrote:

 I am creating a specialized bit pattern (secretly represented as a uint) 
 as a struct S, but want to avoid `alias this` to maintain encapsulation 
 excepting where I overtly say. Specifically, I want to avoid making 
 arithmetic and inequalities available for S.
 
 I have written opEquals to compare an S to a uint.
 
 How do I write code to compare a uint to an S?
 


I didn't know that it works both ways already:

import std.stdio;

struct S {
   bool opEquals(uint u) {
     writeln("called");
     return true;
   }
}

void main() {
   S s;
   s == 7;
   7 == s;
}

There are two "called"s printed...

Ali
Jul 31 2019