E1:     C1 CALL pred exception_cmd.main/2-0 (det) exception_cmd.m:17
mdb> echo on
Command echo enabled.
mdb> exception
      E2:     C2 EXCP pred exception.throw_impl/1-0 (erroneous)
mdb> print *
       Univ (arg 1)           	univ_cons(software_error("oops"))
mdb> continue
Uncaught Mercury exception:
Software Error: oops
Last trace event was event #E3.
Last trace event before the unhandled exception was event #E4.