Option!T

[Andrei Alexandrescu]

On 12/10/13 10:21 AM, Paulo Pinto wrote:
> Am 10.12.2013 18:54, schrieb Yota:
>> On Tuesday, 10 December 2013 at 17:28:26 UTC, Andrei Alexandrescu wrote:
>>> I talked to a programmer who knows Scala (among others) and he
>>> mentioned the usefulness of the Option type - a zero or one element
>>> collection (range in D terminology). Here's an article discussing it:
>>> http://danielwestheide.com/blog/2012/12/19/the-neophytes-guide-to-scala-part-5-the-option-type.html
>>>
>>>
>>
>> I really came to love Option when I was working in F#.  One of the
>> things I love about F# is how the language strongly discourages nulls.
>> Even Anders went on video saying that he regretted making reference
>> types nullable in C#.
>>
>> Of course, there's no way to remove the nullable-by-default nature of
>> reference types in D2, but a guy can dream. =]
>
> It would probably break a lot of code, but the Eiffel, Kottlin's
> approach could be used.
>
> In those languages, unless it is proven that a reference type is valid
> you cannot make use of its value.
>
> Eiffel
> http://docs.eiffel.com/sites/default/files/void-safe-eiffel.pdf
>
> Kotlin
> http://confluence.jetbrains.com/display/Kotlin/Null-safety

Not that this is not worth discussing, but this is a different topic. 
I'm talking about ranges of zero or one elements.

Andrei