break-enable*[Variable]
- This variable is used to determine whether to enter the
break loop (see Section 5.4) when an error occurs. Even the function
break checks this variable. Initially, this variable is set to t, and thus
an error will invoke the break loop. If the value is nil,
functions that cause fatal errors, such as error,
will just print an error message and control will return to the top-level loop
(or to the current break loop, if already in the break loop). Functions
that cause correctable errors, such as cerror,
will print an error message and a ``continue message'', and
control will return to the next form. In KCL, backtrace is not part of an error message, but
a break loop command will print backtrace. Therefore, if *break-enable* is nil,
no backtrace appears on the screen.
- When the break loop is entered, *break-enable*
will be bound to nil.