On 1/28/2015 12:02 AM, deadalnix wrote:
On Wednesday, 28 January 2015 at 07:55:22 UTC, Walter Bright wrote:
On 1/27/2015 8:57 PM, deadalnix wrote:
For ref return, we can still
make it safe by defining the lifetime of the ref return as the intersection of
the lifetime of the ref parameters and call it a day. As far as I can tell, this
cover the vast majority of cases.
The trouble with that is when you *do* need to return a ref that is unrelated
to the ref parameters, there will be no way to do it.
True, but unless you are returning a ref to a static variable, it has to come
from an explicit or an implicit argument.
Or a ref to a new'd object. Or a ref to what the ref parameter pointed to. (ref
is not transitive)
And the solution to this is not an ad hoc way to specify each useful lifetime we
can think of, but have sensible defaults and a generic way to specify them when
default fall short.
I believe DIP25 has the most sensible default that results in the least
disruption. Besides, it makes more sense to say:
"I am returning this parameter"
than:
"I am not returning this parameter, or that one, or this other one, either"
Of course, there is a bit of leap of faith in the "least disruption" thing, only
some experience with the feature will tell for sure.
