Re: some mixin utilities

[Dan]

On Monday, 5 November 2012 at 18:53:20 UTC, Tobias Pankrath wrote:

I like the general style. However this provokes a invinite loop:

Good catch. Fixed. There may be more complex scenarios of nested 
locking references that cause similar loop.


And I would find the comparison more useful, if it uses the 
user defined opEquals for a field if there is one.

Good point, this could be changed easily enough. The point for 
OpEquals was to use this for the issues pointed out in the 
thread. A benefit of just always using typesDeepEqual within 
typesDeepEqual is if I forget a mixin(OpEquals) in some class A, 
agreggated in some B, I'm still covered. So, below my deep equals 
works as expected for B even though A has no suitable opEquals. I 
think this should work even if I do not own A, which is a plus. 
The downside is if there is a custom opEquals for a struct that 
is more efficient it wont get called.

As bearophile pointed out this issue will change anyway. At that 
point I think the OpEquals becomes mute. I hope I'm covered by 
just turning its implementation  into a no-op and my classes 
don't change.

Thanks
Dan

--------------
struct A {
  void pushOne() { i ~= 1; }
private:
  int[] i;
}
struct B {
  mixin(OpEquals);
  A a;
}
void main() {
  A a1, a2;
  a1.pushOne();
  a2.pushOne();
  B b1 = {a1}, b2 = {a2};
  writeln(a1==a2);    // false
  writeln(b1==b2);    // true
}