References in D

[Alex Burton]

On Saturday, 15 September 2012 at 17:51:39 UTC, Jonathan M Davis 
wrote:
> On Saturday, September 15, 2012 19:35:44 Alex Rønne Petersen 
> wrote:
>> Out of curiosity: Why? How often does your code actually 
>> accept null as
>> a valid state of a class reference?
>
> I have no idea. I know that it's a non-negligible amount of the 
> time, though
> it's certainly true that they normally have values. But null is 
> how you
> indicate that a reference has no value. The same goes for 
> arrays and pointers.
> Sometimes it's useful to have null and sometimes it's useful to 
> know that a
> value can't be null. I confess though that I find it very 
> surprising how much
> some people push for non-nullable references, since I've never 
> really found
> null to be a problem. Sure, once in a while, you get a null 
> pointer/reference
> and something blows up, but that's very rare in my experience, 
> so I can't help
> but think that people who hit issues with null pointers on a 
> regular basis are
> doing something wrong.
>
> - Jonathan M Davis

In my experience this sort of attutide is not workable in 
projects with more than one developer.
It all works OK if everyone knows the 'rules' about when to check 
for null and when not to.
Telling team members that find bugs caused by your null 
references that they are doing it wrong and next time should 
check for null is a poor substitute for having the language 
define the rules.

A defensive attitude of checking for null everywhere like I have 
seen in many C++ projects makes the code ugly.