Userdata: Difference between revisions
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==Userdata== | |||
===What is a Userdata?=== | |||
==What is a Userdata?== | |||
A userdata is the type Lua uses for data structures in the underlying C program. There are not native Lua functions for handling those types, they must be handled via [[Metatables]]. All Roblox objects and events are userdata Lua type. | A userdata is the type Lua uses for data structures in the underlying C program. There are not native Lua functions for handling those types, they must be handled via [[Metatables]]. All Roblox objects and events are userdata Lua type. | ||
==Using Userdatas== | ===Using Userdatas=== | ||
You can create a new userdata by passing true to the undocumented newproxy function. This userdata cannot be used for anything other than invoking functions via its metatable. | You can create a new userdata by passing true to the undocumented newproxy function. This userdata cannot be used for anything other than invoking functions via its metatable. | ||
Revision as of 13:45, 24 December 2010
Userdata
What is a Userdata?
A userdata is the type Lua uses for data structures in the underlying C program. There are not native Lua functions for handling those types, they must be handled via Metatables. All Roblox objects and events are userdata Lua type.
Using Userdatas
You can create a new userdata by passing true to the undocumented newproxy function. This userdata cannot be used for anything other than invoking functions via its metatable.
Example
local ud = newproxy(true) -- new userdata with an empty metatable
getmetatable(ud).__index = {Foo = "Bar"} -- index metamethod
print(type(ud), ud.Foo)
Output:
userdata: 0x631fc8 Bar
