This variable is used to control the number of components of an object which are printed during output from the debugger. If its value is a positive integer then the components up to that number are printed. If it is
nil
then all the parts of an object are shown.
USER 83 > (setq dbg:*debug-print-length* 3)
3
USER 84 > (aref
'(1 2 3 4 "Jenny" "cottage" "door")
2)
Error: (1 2 3 4 Jenny cottage door) must be
an array
1 (abort) return to top loop level 0.
Type :c followed by a number to proceed
USER 85 : 1 > :v
Call to ARRAY-ACCESS :
Arg 0 (ARRAY): (1 2 3 ...)
Arg 1 (SUBSCRIPTS): (2)
Arg 2 (SET-P): NIL Arg 3 (VALUE): NIL
LispWorks User Guide and Reference Manual - 21 Dec 2011