On 09/05/11 at 02:31pm, Jason E. Aten wrote: > I think dynamic variables (which are available in Common Lisp but not > in most Schemes, if I understand right) In many Schemes, dynamic variables are approximated by parameter objects, described in SRFI-39 (by none other than Marc Feeley). http://srfi.schemers.org/srfi-39/srfi-39.html Evan