Denis Koroskin <2kor...@gmail.com> wrote:
On Mon, 08 Nov 2010 12:08:01 +0300, Simen kjaeraas
<simen.kja...@gmail.com> wrote:
Eric Poggel <dnewsgro...@yage3d.net> wrote:
On 11/6/2010 6:50 AM, bearophile wrote:
foobar:
Any type can be wrapped by an OPTION type. trying to do the converse
of this is impractical and is bad design.
Discussing this is a waste of time now, this part of the D language
will probably never change.
This is why other people and me are proposition something different.
Bye,
bearophile
I still live in D1 land, so forgive me if I'm out of the loop--but
what keeps this from being implemented at the library level as
templated type: NotNull!(T) ? If there are limitations, maybe these
areas of the language can be improved to get us there?
NotNull!T needs to have its default constructor disabled. That is the #1
blocker. There are other problems, mostly related to this - classes and
structs with NotNull!T fields must define a constructor, and for structs
that means the default destructor either needs to be possible to define
or possible to disable. Arrays of NotNull!T may not be resized to a
greater length, as that would require calling the default constructor of
NotNull!T.
I think that's it.
Not exactly disabled. The following should work:
class Foo
{
this() {
bar = new Object();
}
NonNull!(Object) bar; // fine here
}
while the following shouldn't:
NonNull!(Object) bar; // error here
bar = new Object();
I belive you have misunderstood me. The NonNull struct would need to have
its default constructor disabled. Then, extra logic would need to be added
to class and struct constructors to ensure NonNull fields have their
constructors called.
Context-sensitive constructor disabling is a theoretical possibility, but
seems to me to conflict with D's other goals.
--
Simen
