15.11.08 в 00:30 Steven Schveighoffer в своём письме писал(а):
"Denis Koroskin" wrote
I'm doing some meta stuff and came across a few problems.
First of is described here:
http://d.puremagic.com/issues/show_bug.cgi?id=2454
Bug reports without actual errors listed in them (i.e. 'try this and see
what happens') will probably be ignored. It would do you good to show
what
the errors are.
Second one is slightly different and this time I am less sure whether it
is a bug.
The following code is indetended to print offsets of all its members:
struct Test
{
short s;
int i;
float f;
double d;
void test()
{
writefln("expected output:");
writefln( cast(char*)&s - cast(char*)this ); //
writefln(s.offsetof);
writefln( cast(char*)&i - cast(char*)this ); //
writefln(i.offsetof);
writefln( cast(char*)&f - cast(char*)this ); //
writefln(f.offsetof);
writefln( cast(char*)&d - cast(char*)this ); //
writefln(d.offsetof);
writefln("actual output:");
foreach (m; this.tupleof) {
// writefln(m.offsetof); // Error: no property 'offsetof'
for
type 'short'
writefln( cast(char*)&m - cast(char*)this);
}
}
}
expected output:
0
4
8
16
actual output:
-52
-48
-44
-40
Am I doing something wrong?
Yes, in the code:
foreach(m; this.tupleof)
m is a variable local to the for loop, not a reference to the actual
tuple
member.
I'm not sure foreach(ref m; this.tupleof) will work, I haven't done much
with tuples.
But certainly if ref m does work, the
writefln( cast(char *)&m - cast(char *)this);
should be accurate.
But m.offsetof probably won't, since at that point, m is simply a ref
local
variable, not a member of the struct.
I think possibly the only way offsetof works is in the form
aggregate.member.offsetof. I could be totally wrong.
-Steve
Ooops, sorry. I *hate* when others do like this but accidentially fell to
the same trap. Thank you!
