In NESL most errors result in an error message being printed, and the system returns you to the NESL prompt.
Some errors, however, may cause you to abort out of NESL and back to the Common Lisp prompt. The only case where this is supposed to happen is if you hit Ctrl-C . If it happens in any other situation, please report it as a bug (see Section 6.2). When it does happen, you can return to NESL by getting back to the top level of your Common Lisp system and then typing (nesl).<Nesl> nosuchfunc(2); Error at top level. NOSUCHFUNC is undefined. <Nesl>