Yes, you can use unions. This _DOES_ not correspond to list<any>, but to
union A {
...
}
list<A>.
So, how are unions implemented?
Consider:
union Any {
1: i32 v_i32
2: double v_double
};
In C++ this will become a class with fields
class Any {
int32_t v_i32;
double v_double;
struct __isset {
bool v_i32;
bool v_double;
} __isset;
}
In other words, memory-wise, this is really a structure
Python:
class Any:
def __init__....:
self.v_i32 = ...
self.v_double = ...
Also a struct
It may be different in some of the other languages, of course, or in
v0.3.0, but I'm not sure that the "union" suggestion is that efficient.
Alex Boisvert wrote:
On Mon, May 3, 2010 at 7:09 AM, Bryan Duxbury <[email protected]> wrote:
There is already a totally viable workaround, though - make a Union of the
types you want in your collection, and then make the field list<YourUnion>.
You get basically all the capabilities with very few drawbacks, plus the
ability to include multiple logical "types" in the collection, not just
physical types. Of course, if you literally need "any" possible object to
go
into the collection, then this won't do it for you.
Thanks for the suggestion, Bryan.
I'm experimenting with marshalling my values to strings (I only deal with
basic types such as int32, int64, strings) right now. If that doesn't
work, I'll go with your suggestion.
alex
