assert p x returns x if the application p x yields true. Otherwise,
assert p x fails.
FAILURE
assert p x fails with exception HOL_ERR if the predicate p yields
false when applied to the value x. If the application p x raises an
exception e, then assert p x raises e.
EXAMPLE
- null [];
> val it = true : bool
- assert null ([]:int list);
> val it = [] : int list
- null [1];
> false : bool
- assert null [1];
! Uncaught exception:
! HOL_ERR <poly>