On Thursday, 29 November 2012 at 12:10:06 UTC, Maxim Fomin wrote:
On Thursday, 29 November 2012 at 10:41:46 UTC, Mehrdad wrote:
I'm just not understanding the whole "the default construction
of a struct should be a compile time creature, not a runtime
one".
Don't you have to initialize the struct with zero's either way?
So either way, you're going to have to initialize it... so no
perf increase in any way. Why prevent the user from
default-initializing it the way he wants to?
Every type has a CT-known default initializer, even classes
have (null). If structures had a runtime one, this would break
code (especially templates and CTFE) which relies on knowing
something about constant default instance of a type at CT.
extern bool foo();
struct S
{
int i;
this() {
i = foo() ? 1 : -1;
}
}
---------
S s;
dosmth(s);
---------
//somewhere in Phobos
void dosmth(T) (T obj)
{
T val; // is i 0, -1 or 1 ?
}
Error, S has no default initializer and must be explicitely
initialized.
What is complicated about that ?
