API setmetatable

Sets the metatable for the given table. table = setmetatable(table [, metatable])

• table: - The table to assign or remove the metatable of.
• metatable: - The metatable to be assigned, or nil to remove an existing metatable.

• table: - The table passed in as the first argument.

• The Lua 5.1 reference manual extensively documents the fields that can be set on a metatable.
• As a non-standard extension, metatables can contain an field which impacts the behavior of getfenv.