On 10/03/2012 06:59 PM, Maxim Fomin wrote:
On Wednesday, 3 October 2012 at 16:36:15 UTC, Henning Pohl wrote:
Just put something like a questionmark behind the reference type to
indicate that it's nullable.
...
Not really. It's all about one question mark for example.
How much code would be broken by moving nullable references from current
state to "question mark notation"?
Most of it, and fixing it up quickly may require adding explicit
assertions together with the question marks.
I expect that non-nullable class objects (called references here)
addition (if there is no objections to idea in general) would not break
much code and would not request vast syntax changes. And it likely can
be done by still defaulting to nullable references. For example, it can
be done with the help of @nonnullable (like immutable) type qualifier
and semantic check of operations involving references with such
qualifier. Anyway, my estimation of probability of accepting
constructions like "type&", "type*?", etc and defaulting to non-null
references is very low, at least for D2.
'non-null reference' is an abominable term. It shouldn't have 'null' in
it. I'd just call it a 'reference'. Having a reference type whose
values always refer to an object, while allowing dereferencing
nullable-by-default references at the same time is not worth the effort.
Imho, either break all code or leave it out.
