On 19-06-2012 19:51, Ali Çehreli wrote:
Is the following code legal for a class?
class C {
int i;
}
void main() {
with(new C()) {
i = 42; // <-- Is the anonymous object alive at this point?
}
}
The object seems to live long enough for a class. That's probably
because the garbage collector kicks in late. But consider the same code
with a struct:
import std.stdio;
struct S {
int i;
this(int i = 0)
{
writeln("constructed");
}
~this()
{
writeln("destructed");
}
}
void main() {
with(S(1)) {
writeln("inside 'with' statement");
i = 42; // <-- Is the anonymous object alive at this point?
}
}
The output indicates that the anonymous object is destroyed before the
body of the with is executed:
constructed
destructed
inside 'with' statement
This contradicts with with's spec:
http://dlang.org/statement.html#WithStatement
It says that
with (expression)
{
...
ident;
}
is semantically equivalent to:
{
Object tmp;
tmp = expression;
...
tmp.ident;
}
Bug?
Ali
I say bug.
BTW, the reason the class reference is alive is because it's on the
stack. Regardless of whether you're using with, it wouldn't be collected
by the GC until the current stack frame exits.
--
Alex Rønne Petersen
[email protected]
http://lycus.org
