E1:     C1 CALL pred exception_value.main/2-0 (cc_multi) exception_value.m:18
mdb> echo on
Command echo enabled.
mdb> register --quiet
mdb> break p
 0: + stop  interface pred exception_value.p/1-0 (det)
mdb> break q
 1: + stop  interface pred exception_value.q/1-0 (det)
mdb> continue
      E2:     C2 CALL pred exception_value.p/1-0 (det) exception_value.m:36 (exception.m:NNNN)
mdb> finish
      E3:     C2 EXCP pred exception_value.p/1-0 (det)
mdb> print exception
	"p exception"
mdb> continue
exception(univ_cons("p exception"))
      E4:     C3 CALL pred exception_value.q/1-0 (det) exception_value.m:41 (exception.m:NNNN)
mdb> finish
      E5:     C3 EXCP pred exception_value.q/1-0 (det)
mdb> browse exception
browser> depth 9
browser> size 99
browser> ls
"q oops" - [1, 2, 3]
browser> quit
mdb> continue
exception(univ_cons("q oops" - [1, 2, 3]))