Safe Navigation Operator “?.” for D2 ?

[Marc Schütz" <schuetzm at gmx.net>]

On Friday, 28 February 2014 at 11:11:28 UTC, Dicebot wrote:
> On Friday, 28 February 2014 at 09:24:23 UTC, John Colvin wrote:
>>> Chaining . operation is a code smell to begin with
>>
>> It is? Why?
>
> If a system is well-designed, then "null" state either means 
> something (and needs to be explicitly handled) or is not 
> possible.
>
> ?. provides simple and easy way to write a sloppy code that 
> does not tell the reader if resulting code flow for null case 
> was intentional. Also it is very easy to get accustomed to use 
> ?. everywhere instead of . and get broken logic instead of 
> NullPointerException for cases when pointer is wrongly assumed 
> to never be null.

I sometimes come across situations like this:

writeln_or_whatever(person ? person.name : "");

(This is a case of "means something".)

Using `person?.name` is a bit shorter and DRYer. But it would be 
more useful if I could specify the default value it returns. With 
an explicit `maybe` this would be possible:

person.maybe("<n/a>").name;