8 The Debugger
Upon entering the debugger, a message describing the error is printed, and a number of options presenting ways to continue execution -- called restarts -- are listed.
CL-USER 6 > fubar Error: the variable FUBAR is unbound. 1 (continue) Try evaluating it again. 2 Return a value to use. 3 Return a value to set it to. 4 (abort) return to level 0. 5 return to top level loop 0. Type :c followed by a number to proceed CL-USER 7 : 1 >Two special restarts can be listed: the abort and continue restarts. These are indicated by the prefixes
(abort)
and (continue)
respectively.
The continue restart can be invoked by typing :c
alone. It performs different operations in different circumstances -- in this case, it allows you to evaluate the form again. If you first bind the variable to some value, and then invoke the continue restart, you will leave the debugger:
CL-USER 7 : 1 > (setq fubar 12) 12 CL-USER 8 : 1 > :c 12 CL-USER 9 >The abort restart can be invoked by entering
:a
. It always exits the current level and returns to the previous one, ignoring the error which caused the present invocation of the debugger.
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