For exanple, this is the error message I would expect to see for an unbound variable: hkt@pinhead:~ [10]% clisp [1]> messiaen *** - EVAL: variable MESSIAEN has no value The following restarts are available: STORE-VALUE :R1 You may input a new value for MESSIAEN. USE-VALUE :R2 You may input a value to be used instead of MESSIAEN. 1. Break [2]> :r1 New MESSIAEN: god GOD [3]> messiaen GOD [4]>