On 01/16/2013 09:45 PM, Era Scarecrow wrote:
> (Do they have to be structs?) If they
> don't and you add code, can that code help/add or modify the attributed
> object (or can it at all?).
It looks like some mixin magic can be used.
> Do the structs have to be empty?
They can have members. getAttributes preserves the types and values of
the attributes. It returns a tuple.
With the warning that I don't have any experience with attributes, the
following program uses an attribute type that has a member to indicate
the number of times that a variable must be serialized. (Stupid idea. :))
import std.stdio;
struct Serialize
{
size_t count;
}
struct S
{
@Serialize(3) int x;
int y;
@Serialize(2) int z;
}
void foo(T)(T s)
{
foreach (member; __traits(allMembers, T)) {
foreach (attr;
__traits(getAttributes, mixin(T.stringof ~ '.' ~
member))) {
if (typeid(attr) is typeid(Serialize)) {
writefln("%s has %s", member, attr);
writefln("must serialize %s %s times", member, attr.count);
foreach (count; 0 .. attr.count) {
writefln(" serializing %s", member);
}
}
}
}
}
void main()
{
auto s = S();
foo(s);
}
The output shows that only x and z are serialized according to their
respective serialization counts:
x has Serialize(3)
must serialize x 3 times
serializing x
serializing x
serializing x
z has Serialize(2)
must serialize z 2 times
serializing z
serializing z
Ali
