HsLua.Core.Userdata

Convenience functions to convert Haskell values into Lua userdata.

Documentation

newhsuserdata :: forall a e. a -> LuaE e ()

Creates a new userdata wrapping the given Haskell object. The userdata is pushed to the top of the stack.

newudmetatable :: Name -> LuaE e Bool

Creates and registers a new metatable for a userdata-wrapped Haskell value; checks whether a metatable of that name has been registered yet and uses the registered table if possible.

Using a metatable created by this functions ensures that the pointer to the Haskell value will be freed when the userdata object is garbage collected in Lua.

The name may not contain a nul character.

fromuserdata

Arguments

:: forall a e. StackIndex

stack index of userdata

-> Name

expected name of userdata object

-> LuaE e (Maybe a)

Retrieves a Haskell object from userdata at the given index. The userdata must have the given name.

putuserdata

Arguments

:: forall a e. StackIndex

index

-> Name

name

-> a

new value

-> LuaE e Bool

Replaces the Haskell value contained in the userdata value at index. Checks that the userdata is of type name and returns True on success, or False otherwise.