> On Behalf Of Geoff Leyland
Sent: maandag 8 oktober 2012 8:39
On 8/10/2012, at 6:58 PM, Thijs Schreijer <thijs@thijsschreijer.nl>
wrote:
Typex traverses the registry to find the name of the metatable and
returns that as a second argument. The results of the registry
traversal are then cached to speed-up next searches.
Nice idea! Am I right in thinking that it only works for userdata, not
tables-as-objects?
Yes, only userdata metatables. Metatables on tables do not necessarily have
a name registered in the registry. Though it would be easy to extend it.
The
general purpose is only an equality check (or am I overlooking something?)
So to check on equality all that is necessary is doing a tostring() on the
metatable for a unique string. The part not covered would then be the case
where similar 'objects' get a new (but similar) metatable as in;
function whatever()
local result
-- do something
return setmetatable(result, {value1, value2})
end
In that case an __type field/function could be used
So adding it up;
- for userdata and tables, check on __type metatable field
If __type found then
- if it's a field return its value
- if it's a function call is with self (the original userdata/table) as
parameter and return that
If __type not found
- for a userdata look up the metatable name in the registry and return
that.
- for a table do a raw tostring() (no __tostring metamethod) on the
metatable and return that
Thijs
