From: Asger Alstrup Nielsen (alstrup_at_[hidden])
Date: 2002-02-28 07:57:54
> > Jens' describe() scheme is fine, but it doesn't extend to attributes well,
> > and doesn't handle versioning (it makes things assymetrical.)
>
> I haven't looked at Jens' scheme.
In as far as Jens' scheme is comparable to XTL, versioning is trivial:
class Foo {
int oldMember; // Only in version 0
int newMember; // In version 0 and 1
template<class S>
void serialize(S & s) {
int version = 1;
s.stream(version);
switch(version) {
case 0:
// code for reading old version 0 data
s.serialize(oldMember);
newMember = defaultValue;
break;
case 1:
// code for both reading & writing version 1
s.serialize(oldMember);
s.serialize(newMember);
break;
default:
throw "Unsupported version";
}
}
};
Greets,
Asger Alstrup Nielsen