Breakpoints, continued

The current procedure is available from (*proc*), the arguments from (*args*), and the result (at the exit of a procedure) from (*result*).
Breakpoints are removed using unbreak (or unbreak-entry or unbreak-exit). All breakpoints can be removed (from all procedures) using (unbreak), etc.
Exit breakpoints also "break tail recursion."
Internal procedures can have breakpoints inserted, as in trace.