Here is a little problem with read tables noted by Mike Smith. % kcl KCl (Kyoto Common Lisp) June 3, 1987 >(setq rt1 (copy-readtable nil)) #<readtable 00145748> >(setq rt2 (copy-readtable nil)) #<readtable 00145740> >(copy-readtable rt1 rt2) Segmentation fault (core dumped) %