break/0 [development]break
causes the current execution to be interrupted; enters next break level.
The first time
break/0 is called, it displays the message
% Break level 1
% 1
| ?-
The system is then ready to accept input as though it were at top
level. If another call to break/0 is encountered, it moves up
to level 2, and so on. The break level is displayed on a separate
line before each top-level prompt.
To close a break level and resume the execution that was suspended,
type ^D. break/0 then succeeds, and execution of the
interrupted program is resumed.
Changes can be made to a running program while in a break level. Any change made to a procedure will take effect the next time that procedure is called. See ref-mdb-rcd for details of what happens if a procedure that is currently being executed is redefined. When a break level is entered, the debugger is turned off (although leashing and spypoints are retained). When a break level is exited, the debugging state is restored to what it was before the break level was entered.
Often used via the debugging option b.
abort/0, halt/[0,1], Nested.