space_object extensions

You can extend space_object with custom functions as follows:

1. Create a Lua function.
2. Add the function name to a predefined global variable box.schema.space_mt, which has the table type. Adding to box.schema.space_mt makes the function available for all spaces.
3. Call the function on the space_object: space_object:function-name([parameters]).

Alternatively, you can make a user-defined function available for only one space by calling getmetatable(space_object) and then adding the function name to the meta table.

See also: /reference/reference_lua/box_index/user_defined.

Example:

 
-- Visible to any space, no parameters.-- After these requests, the value of global_variable will be 6.box.schema.space.create('t')box.space.t:create_index('i')global_variable = 5function f(space_arg) global_variable = global_variable + 1 endbox.schema.space_mt.counter = fbox.space.t:counter()