SBCL supports @dfn{Gray streams}, user-overloadable CLOS classes whose
instances can be used as Lisp streams (e.g. passed as the first
argument to @code{format}). Additionally, the bundled contrib module
SBCL supports @dfn{Gray streams}, user-overloadable CLOS classes whose
instances can be used as Lisp streams (e.g. passed as the first
argument to @code{format}). Additionally, the bundled contrib module