(define (ac-call fn args env)
      (let ((macfn (ac-macro? fn)))
        (if macfn
          (ac-mac-call macfn args env)
          (let ((afn (ac fn env))
                (aargs (map (lambda (x) (ac x env)) args))
                (nargs (length args)))
            (cond 
              ((eqv? (xcar fn) 'fn)
               `(,afn ,@aargs))
              ((and (>= nargs 0) (<= nargs 4))
               `(,(string->symbol (string-append "ar-funcall" (number->string nargs)))
                                  ,afn ,@aargs))
               (#t
                `(ar-apply ,afn (list ,@aargs))))))))