It doesn't seem to support closures.

    User>(defun accgen (x)
            (lambda (y)
               (incf x y)))

    ACCGEN
    User>(setf foo (accgen 5))

    <Interpreted Lisp Function>
    User>(funcall foo 5)

    NaN
    User>(let ((bar "bar"))
            (defun qux ()
               (print bar)))

    QUX
    User>(qux)

    null
    User>