Re: how to achieve C's Token Pasting (##) Operator to generate variable name in D?

[mw via Digitalmars-d-learn]

On Sunday, 31 May 2020 at 06:28:11 UTC, mw wrote:
This is better, ... but it breaks std.traits:
void main() {
  auto fields = FieldNameTuple!(Point);
  writeln(fields);
}

$ ./b
varvarvar

And normally, we cannot define 2 fields with different types:

class P {
  int x;
  double x;  // b.d(45): Error: variable b.P.x conflicts with 
variable b.P.x at b.d(44)
}

With the above template we somehow tricked the compiler to be 
able to do this?

Is this a loop-hole we should file a bug?


This is related to D's silent crept-in multiple inheritance 
problem, a solution via language improvement is here:

https://forum.dlang.org/post/lsnhqdoyatkzbzqbs...@forum.dlang.org


I'd imagine something like this:

----------------------------------------------------------------------
class Person : NameI, AddrI {
  mixin NameT!Person rename equals as name_equals;
  mixin AddrT!Person rename equals as addr_equals;

  bool equals(Person other) {
    return this.name_equals(other) &&
           this.addr_equlas(other);
  }
}
----------------------------------------------------------------------