On Tuesday, 13 May 2014 at 17:09:17 UTC, Steven Schveighoffer
wrote:
On Tue, 13 May 2014 09:50:12 -0400, Dicebot <[email protected]>
wrote:
On Tuesday, 13 May 2014 at 13:40:42 UTC, Jacob Carlborg wrote:
On 13/05/14 15:36, Dicebot wrote:
There are 2 `scope` uses to think about. One is storage
class and in
that context `scope` is more of owned / unique pointer.
Other is
parameter qualifier and that one is closer to ref / borrowed
pointer.
Main problem about making `ref` borrowed pointer is that you
will need
to prohibit storing it in function transitively. This will
need to
become invalid code:
struct A
{
int* ptr;
}
int* gptr;
void foo(ref A a)
{
gptr = a.ptr; // error, can't leak borrowed a.ptr into
global context
}
This feels like too much of a breakage, this is why `scope`
(or `scope
ref`) feels more appropriate.
I always though "scope" would behave like that.
Walter's initial post implies that he wanted to re-used `ref`
for borrowed pointer (which would mean same semantics as
`scope` parameter qualifier)
Yes, the difference here is that scope is a storage class, and
only affects the "head", whereas borrowed would have to be
transitive.
-Steve
`scope` has to be both storage class and qualifier to work
