Scott, Evaluation of this form fails with an error: (with-standard-io-syntax (let ((*readtable* (copy-readtable *readtable*)) (v (with-default (map) (set)))) (fset::fset-setup-rereading-readtable *readtable*) (with-input-from-string (s (with-output-to-string (s) (write (list v) :stream s))) (read s)))) ..whereas this succeeds: (with-standard-io-syntax (let ((*readtable* (copy-readtable *readtable*)) (v (map))) (fset::fset-setup-rereading-readtable *readtable*) (with-input-from-string (s (with-output-to-string (s) (write (list v) :stream s))) (read s)))) ...which probably suggests that the reader hasn't been conditioned to take care of the trailing "/foo" syntax. -- regards, Samium Gromoff -- "Actually I made up the term 'object-oriented', and I can tell you I did not have C++ in mind." - Alan Kay (OOPSLA 1997 Keynote)