On Sun, 19 May 2013 06:57:16 +0200, Walter Bright
<newshou...@digitalmars.com> wrote:
The current solution is to rely on faith, and I remember someone
talking about
that at DConf recently.
Rely on what faith?
void foo(int* p) {} // p must never be null
void foo(NotNull!(int*) p) {}
One of these is tested at compile time, *and* includes valuable
documentation in the signature. The other is either less performant
or buggy.
Now that what other languages does is cleared, let's do some
consideration on null.
A pointer point on something. For instance, an int* point on an
integer. null
doesn't point on a integer. Non nullable pointer aren't a restricted
set of
values, as, by definition, null isn't a value that point to an int.
That doesn't
stand either.
By definition? Pointer semantics are what we choose it to mean.
Of course. But which definition is saner:
"T* is either a valid pointer to a T, or a value that blows up when used
in certain ways (but not others)."
or
"T* is a valid pointer to T."
Of course, the latter also requires something like Maybe!T:
"Maybe!T is either a valid pointer to a T, or a value on which no
operations may be performed. In order to gain access to the T, both
cases have to be handled."
--
Simen
