Proposing std.typecons : Optional (with PR) + rant

[Aliak]

On Tuesday, 11 June 2019 at 19:02:12 UTC, Ola Fosheim Grøstad 
wrote:
> On Tuesday, 11 June 2019 at 18:01:32 UTC, Nick Treleaven wrote:
>> I'd actually rather have language-assisted optional types than 
>> features like function overloading (a convenience feature, 
>> sometimes abused), because it means *the type system can model 
>> runtime checks as a static type guarantee*. They are a game 
>> changer.
>
> I don't disagree, but one often end up creating a Nobody 
> subclass singleton that is used as a replacement for null. 
> Although that does have benefits (e.g. if you call a 
> nobody.name() you get "nobody" rather than a crash).

If there’s a possibility your class can be null then it should 
probably be an optional. Or lazy. Have not seen this pattern you 
describe in swift scala or Kotlin.