Error handling is quite different in Common Lisp than in other languages. Assert is also different. An assert has up to three parts: 1. The expression to be as

Error handling is quite different in Common Lisp than in other languages. Assert is also different. An assert has up to three parts: 1. The expression to be asserted 2. A set of places (ie variables/references) 3. A format datum and arguments (like sprintf) When an assert fails you see the formatted message from (3) and get some options: - invoke a restart to some place higher up the control stack - invoke the restart generated by the assert which asks for new values for the set of places in step 2, and then retries the assert - abort - crash These options may be invoked by the program itself or by the user if the debugger is invoked