Le 25/07/2012 12:30, monarch_dodra a écrit :
On Wednesday, 25 July 2012 at 09:51:49 UTC, Jonathan M Davis wrote:
If you want to be able to do S(), then declare a static opCall for S
which
returns an S constructed in the way that you want.
struct S
{
static S opCall()
{
//do whatever you do
return s;
}
}
auto s = S();
but
S s;
will always be init. But you can't have a default constructor, because
then it
conflicts with what init would be doing. e.g. would
S s;
[SNIP]
This makes *so* much sense now. I couldn't understand the point of "S a
= S();" up until now. Thanks a lot.
I read TDPL back to back like 5 times before posting this, but it never
mentions opCall. I just checked the index right now, it is not in there.
Is this new?
Provided the existence of "opCall", though why would I keep writing
constructors?
new S(args); // Allocate on the heap instead of the stack
But forget about new S();
Also, while I understand why we can't have a "default" constructor, your
explanations perfectly proves we *can* have a "no-arg" (subtle
difference) one:
S s = S(); //Initialize s to this();
S s; //Leave s as S.init
It seems like opCall is a bypass to a language restriction...
It is. If something should go, it is for me the static opCall hack.
