The standard types and routines can all be implemented using the built-in types and routines; they have no special status in the language. However, the Theta implementation is free to implement some of these types and routines directly rather than on top of the built-ins. Therefore, these types and routines, if available, may be more efficient than corresponding user-defined types and routines.
The full set of standard types and routines has not been determined; a future version of the reference manual will provide the definitive list. We expect to include some parsing routines (for converting strings to built-in types). Two types that we expect to include are "set" and "bag" (multiset).