Re: Unexpectedly nice case of auto return type

[mipri via Digitalmars-d-learn]

On Tuesday, 3 December 2019 at 10:02:47 UTC, Andrea Fontana wrote:

On Tuesday, 3 December 2019 at 09:48:39 UTC, Basile B. wrote:

You see what surprises me here is that we cannot express the special type that is `TypeNull` and that can only have one value (`null`) so instead we have to use `auto` or `typeof(null)`.

You can still create an alias anyway :)

alias TypeNull = typeof(null);

Speaking of nice stuff and aliases, suppose you want to
return a nice tuple with named elements?

Option 1: auto

  auto option1() {
      return tuple!(int, "apples", int, "oranges")(1, 2);
  }

Option 2: redundancy

  Tuple!(int, "apples", int, "oranges") option2() {
      return tuple!(int, "apples", int, "oranges")(1, 2);
  }

Option 3: an alias

  alias BadMath = Tuple!(int, "apples", int, "oranges");

  BadMath option3() {
      return BadMath(1, 2);
  }

It wasn't obvious to me that BadMath(...) would work.
It *should* be obvious since this also works:

  ...
      return Tuple!(int, "apples", int, "oranges")(1, 2);

But the convenience of tuple() helped to  mask that.

I was going with silly stuff like

  ...
      return cast(BadMath) tuple(1, 2);