| catch/4 | As catch/3, only catching exceptions for which exception(ErrorType,Ball) is true. |
| error_term/2 | Describe the formal part of error(Formal,ImplDefined) exceptions. |
| exception/2 | If Ball is unbound, adds a delayed goal that tests the error belongs to Type when Ball is instantiated (by catch/3). |
| exception_term/2 | Describe exceptions that are not error(Formal, _) terms. |
| exception_type/2 | Declare all exceptions subsumed by Term to be an exception of Type. |