On Monday, 27 May 2013 at 06:59:31 UTC, Jonathan M Davis wrote:
On Monday, May 27, 2013 08:49:37 Rob T wrote:
So will introducing non-nullable references make things worse
or
have no practical effect?
We're going to add non-nullable references as a library type
(NotNull!T or
NonNullable!T or somesuch). That will allow you to type
references as being
non-nullable. It doesn't give quite as high a gain as having
them being a
built-in type, but there's a definite cost to adding something
to the language
(far higher than adding it to the library), and we don't think
that the cost
is worth it.
What need to be added to the language to make the lib work is
equivalent to what is needed to make it the default (Make the
compiler track initialization), and is also required for other
aspects of the language (initialize immutable objects).
If I do agree that the cost in regard to code broken is high (and
probably prohibitive) the cost in term of language complexity
isn't what you claim it is.
Additionally, safe behavior are either Nullable, with obligation
to handle the null case from the user (which is easy to provide
as a lib in D) or NonNullable. The default is the worst of both
world, as it is nullable, without any obligation to handle that
case and simply causing the program to crash (plus it will
require runtime checks to make things @safe).
Again, it's not the case that null references aren't a problem.
It's just that
they're being blown of proportion, and it's just not worth
adding a built-in
type to deal with them at this point (let alone making
references in general
non-nullable by default as some people would like done). You
don't add new
features to a language to solve every bug that comes along. We
have a powerful
language. Let's take advantage of it. The library solution
should be fine. It
just isn't as extreme a solution as some people would like.
Many people here have expressed real problem with null, a lot of
documentation on the web exists about it as well, and most modern
languages try as hard as possible to get rid of it (even sometime
in creative way as scala does as they can't get rid of it
completely because of java compatibility).
