Re: Implicit conversion of struct to bool for if (s) operation ?

[John via Digitalmars-d-learn]

On Monday, 6 June 2016 at 15:23:50 UTC, chmike wrote:

Hello,

I have a structure with two fields ad defined as

struct Info {
    this(int value, Category category)
    {
        category_ = category;
        value_ = category ? value : 0;
    }

      // This converts implicitly to bool.
      T opCast(T : bool)() {
          return category_ !is null;
      }

    ...
private:
    Category category_ = null;
    int value_ = 0;
}

I would like an implicit conversion of Info to bool that return false if category_ is null so that I can write

Info s = foo();
if (s) {
   ...
}

and where

Info s2;
assert(!s2);

See the inserted code above.