What is the rationale behind enabling Nullable!T to be used as a regular T?

[Paul Backus]

On Friday, 14 February 2020 at 17:04:28 UTC, Adnan wrote:
> On Friday, 14 February 2020 at 14:43:22 UTC, Petar Kirov 
> [ZombineDev] wrote:
>> On Friday, 14 February 2020 at 08:54:41 UTC, Adnan wrote:
>> The two ends of the design spectrum (as I see it) are:
>> 1. `Optional(T) x` as a range of [0,1] elements of type `T`. 
>> For all possible operations `op` on type `T` there exists an 
>> operation `Option(T).op` and the effect of executing is 
>> equivalent to `x.map!fun`. This is what aliak's optional 
>> package provides.
>
> Very interesting. I always thought that Option<T> is a 
> type-guard for enforced null checks (I could be wrong here). 
> But seems to me that this design circles back to square 1: 
> having the callee remember to check if the length of the range 
> is 0 or 1. Which is essentially similar to check sentinel 
> values (i.e. check if the binarysearch returns -1 as index). 
> What languages do this?
>
> What does Aliak's package provide that's fundamentally 
> different to just returning a T[]? Empty T[] would mean `None` 
> and a T[] with 1 item means `Some(T)`?

Aliak's package offers several features in addition to the range 
interface that make it more convenient to work with than a simple 
array. You can see a list in the README:

https://github.com/aliak00/optional/blob/v1.0.0/README.md#features