On Wednesday, 3 October 2012 at 08:11:32 UTC, Franciszek Czekała
wrote:
On Saturday, 15 September 2012 at 17:12:23 UTC, Jonathan M
Davis wrote:
On Saturday, September 15, 2012 15:24:27 Henning Pohl wrote:
On Saturday, 15 September 2012 at 12:49:23 UTC, Russel Winder
wrote:
> On Sat, 2012-09-15 at 14:44 +0200, Alex Rønne Petersen
> wrote:
> […]
>
>> Anyway, it's too late to change it now.
>
> I disagree. There are always opportunities to make changes
> to
> things,
> you just have manage things carefully.
I don't know if people really use the ability of references
being
null. If so, large amounts of code will be broken.
Of course people use it. Having nullable types is _highly_
useful. It would
suck if references were non-nullable. That would be _horrible_
IMHO. Having a
means to have non-nullable references for cases where that
makes sense isn't
necessarily a bad thing, but null is a very useful construct,
and I'd _hate_
to see normal class references be non-nullable.
- Jonathan M Davis
Agreed. Nullable types are a feature not a bug. There is no
need to change it. Bugs occur when you do not know the language
rules and make assumptions instead. This can happen whith any
language and any rules. As to an example use of nullable
references: consider a board game (for example chess). The
boards has cells which can be empty or occupied. Model this
with an array of class objects representing pieces. null
reference means a cell is not occupied. If you want to remove a
piece from the board assign null to it and GC will take care of
the rest. Now, doing this with full objects representing empty
cells would require needless work to define such "null" objects
and would be wasteful of memory (typically boards are sparsely
populated). Now imagine a really big board and every cell
holding references to useless objects simulating null
references. It would not make sense. Saying that null
references are evil is just propaganda. Let's keep D a sane
language.
Regarding my example: we could probably do with a single "null"
object stored in all empty cells, but still this would be an
unnecessary complication.
