On Wed, 23 Feb 2011 10:35:26 -0500, Andrei Alexandrescu
<seewebsiteforem...@erdani.org> wrote:
On 2/23/11 9:00 AM, Steven Schveighoffer wrote:
On Wed, 23 Feb 2011 08:04:49 -0500, Andrei Alexandrescu
<seewebsiteforem...@erdani.org> wrote:
On 2/22/11 3:14 PM, Steven Schveighoffer wrote:
On Tue, 22 Feb 2011 15:48:42 -0500, %u <wfunct...@hotmail.com> wrote:
D pure functions are significantly different than this definition
(as of recent times, when weak-pure was added).
Essentially, a pure function cannot access global variables.
However, it can access variables referred to via a member of the
object instance.
i.e. this is a valid pure function:
class C
{
int x;
pure void foo() { x++; }
}
I... did not know that. But even in that case, pure wouldn't make
much
sense, because doing anything like freeing memory or closing a file
handle affects global variables (whether directly in the runtime or
indirectly in the OS)... right?
Freeing and allocating memory is fair game for pure functions.
I don't think freeing memory is pure.
Why not? If it shouldn't be allowed, it should be easy to show with an
example of why.
-Steve
free(p) affects data remotely outside the pure function.
This is allowed however in the new pure regime:
pure void foo(int *x) {(*x)++;}
int x;
foo(&x);
Or do you mean something else?
-Steve
