Get all UserData methods (and functions) in a given Lua instance

[Danielkonge]

If I have a program that implements UserData for multiple different Rust objects for a given Lua instance, is there any way to get a list of all of the UserData object names and their methods (and functions)?

I would like to use this to generate stubs for LuaLS, and I already figured out how to get elements from globals() and other places, but I don't see any way to get this information for UserData? I thought I might be able to use UserDataRegistry, but that seems to only contain private fields without a way to get information out?

If I can't get the names of all the UserData, is there at least a way to figure out all methods (and functions) for the UserData of a given name?

[khvzak]

UserDataRegistry is only a helper object that used to construct a metatable for UserData (once).
In general you can try to fetch userdata metatable and explore the ___index and __newindex content.
But sometimes it can be tricky if they point to a function than a table.

But proper solution would be adding this information to one of metatable fields.

[Danielkonge]

I am not sure I follow exactly what you are suggesting. Do you think the easiest solution for getting the methods of a given UserData object is to save information about which methods are implemented for that kind of object in a UserData field?

And there is no method for figuring out which UserData objects are available in a given Lua instance?

[khvzak]

Do you want to explose userdata objects from Rust or from Lua?

there is no method for figuring out which UserData objects are available in a given Lua instance?

What do you mean? In general there is no simple way to track how many objects of a particular type exist in Lua.

[Danielkonge]

Do you want to explose userdata objects from Rust or from Lua?

I want to explore the UserData objects from Rust if possible, but I don't need information about a specific instance of the object if that makes sense.

I would ideally want a way to know the name of all structs that implement UserData and then a way to figure out which methods (maybe even just the names of the methods) each of these UserData objects define in their implementation of UserData.

For now I have thought about creating my own extra struct on the side (that would have nothing to do with Lua, but just include me writing the information I need in a separate struct) for each struct that implements UserData. But it would be nice if there was some easier way to get the information I need.

What do you mean? In general there is no simple way to track how many objects of a particular type exist in Lua.

I am not interested in knowing how many objects of a particular type exists, instead I am interested in knowing what types exists in my current Lua environment (does that makes sense?).