diff --git a/beautiful-racket-demo/basic-demo-3/expander.rkt b/beautiful-racket-demo/basic-demo-3/expander.rkt
index a8e61b1..c0440d9 100644
--- a/beautiful-racket-demo/basic-demo-3/expander.rkt
+++ b/beautiful-racket-demo/basic-demo-3/expander.rkt
@@ -12,8 +12,10 @@
         (find-property 'b-import-name #'(LINE ...))]
        [(EXPORT-NAME ...)
         (find-property 'b-export-name #'(LINE ...))]
-       [((SHELL-ID SHELL-VAL) ...)
-        (make-shell-ids-and-values caller-stx)] 
+       [((SHELL-ID SHELL-IDX) ...)
+        (for/list ([idx (in-range 10)])
+          (list (suffix-id #'arg idx #:context caller-stx)
+                idx))] 
        [(UNIQUE-ID ...)
         (unique-ids
          (syntax->list #'(VAR-ID ... SHELL-ID ...)))])
@@ -24,7 +26,8 @@
        (require IMPORT-NAME) ...
        (provide EXPORT-NAME ...)
        (define UNIQUE-ID 0) ...
-       (set! SHELL-ID SHELL-VAL) ...
+       (let ([clargs (current-command-line-arguments)])
+         (set! SHELL-ID (get-clarg clargs SHELL-IDX)) ...)
        LINE ...
        (define line-table
          (apply hasheqv (append (list NUM LINE-FUNC) ...)))
@@ -32,6 +35,11 @@
            ([current-output-port (basic-output-port)])
          (void (run line-table))))))
 
+(define (get-clarg clargs idx)
+  (with-handlers ([exn:fail? (λ (exn) 0)])
+    (let ([val (vector-ref clargs idx)])
+      (or (string->number val) val))))
+
 (begin-for-syntax
   (require racket/list)
   
@@ -42,13 +50,5 @@
     (unique-ids
      (for/list ([stx (in-list (stx-flatten line-stxs))]
                 #:when (syntax-property stx which))
-       stx)))
-
-  (define (make-shell-ids-and-values ctxt)
-    (for/list ([idx (in-naturals)]
-               [val (current-command-line-arguments)])
-      (with-pattern
-          ([SHELL-ID (suffix-id #'arg idx #:context ctxt)]
-           [SHELL-VALUE (or (string->number val) val)])
-        #'(SHELL-ID SHELL-VALUE)))))
+       stx))))