Converting s-expressions (Lisp/Scheme) into Javascript (JSON)

sjs.scm

(define (js-format l)                                                                
  (cond                                                                              
    ((null? l) "")                                                                   
    ((not (list? (car l))) (string-append (format #f "'~a'" (car l))                 
                                          (if (not (null? (cdr l)))                  
                                              (string-append "," (js-format (cdr l)))
                                              "")))                                  
    (else (string-append "\n[" (js-format (car l))                                   
                                (if (not (null? (cdr l)))                            
                                    (string-append "]," (js-format (cdr l)))         
                                    "]")  ))))