On 12/13/18 8:17 AM, aliak wrote:
On Thursday, 13 December 2018 at 12:08:22 UTC, Boris-Barboris wrote:
On Thursday, 13 December 2018 at 09:51:42 UTC, aliak wrote:
[...]
You can just move in container constructor:
struct S {
@disable this(this);
this(int i) {}
}
struct Container(T) {
T value;
this(T value) {
import std.algorithm: move;
this.value = value.move;
}
}
void main() {
auto a = Container!S(S(3));
}
Ah. Is there any case where you would not want to do that when you have
a T value as parameter?
Probably not an issue. Note that if you take the parameter by value, the
T must be an rvalue if it has disabled postblit.
In other words, this wouldn't work:
S s;
auto a = Container!S(s); // error
So moving it isn't going to affect anything outside the function.
And, what if it's "this()(auto ref T value)"? Then moving could be
dangerous if the parameter was passed as a ref. Or maybe it just
wouldn't compile?
What will happen is then you *could* take an already existing T as a
parameter, and the T you pass in will be destroyed upon calling the
constructor.
move resets the original to the .init value if it has a destructor or
postblit.
Is it dangerous? Probably not, but you may want to document for anyone
who uses the container to expect that.
-Steve
