impc:ti:block:check-for-free-syms   scheme

(define impc:ti:block:check-for-free-syms
  (lambda (ast esyms)
                                        ;(print 'check: 'ast: ast 'esyms: esyms)
    (cl:remove-duplicates (let loop ((lst ast))
                            (cond ((pair? lst)
                                   (append (loop (car lst))
                                           (loop (cdr lst))))
                                  ((atom? lst)
                                   (if (member lst esyms)
                                       (list lst)
                                       '())))))))