diff --git a/beautiful-racket-demo/basic-demo-3/expander.rkt b/beautiful-racket-demo/basic-demo-3/expander.rkt
index a451b9d..584422f 100644
--- a/beautiful-racket-demo/basic-demo-3/expander.rkt
+++ b/beautiful-racket-demo/basic-demo-3/expander.rkt
@@ -8,15 +8,16 @@
       ([((b-line NUM STMT ...) ...) #'(LINE ...)]
        [(LINE-FUNC ...) (prefix-id "line-" #'(NUM ...))]
        [(VAR-ID ...) (find-property 'b-id #'(LINE ...))]
-       [(REQ-SPEC ...) (find-property 'b-import-name #'(LINE ...))]
+       [(IMPORT-NAME ...)
+        (find-property 'b-import-name #'(LINE ...))]
        [((SHELL-ID SHELL-VAL) ...)
         (for/list ([(val idx) (in-indexed (current-command-line-arguments))])
-                  (list (suffix-id #'arg idx #:context caller-stx) val))])
+          (list (suffix-id #'arg idx #:context caller-stx) val))])
     #'(#%module-begin
        (module configure-runtime br
          (require basic-demo-3/runtime)
          (configure-this!))
-       (require REQ-SPEC) ...
+       (require IMPORT-NAME) ...
        (define VAR-ID 0) ...
        (provide VAR-ID ...)
        (set! SHELL-ID SHELL-VAL) ...
@@ -32,6 +33,6 @@
     (remove-duplicates
      (for/list ([stx (in-list (stx-flatten line-stxs))]
                 #:when (syntax-property stx which))
-               stx)
+       stx)
      #:key syntax->datum)))
 
diff --git a/beautiful-racket-demo/basic-demo-3/expr.rkt b/beautiful-racket-demo/basic-demo-3/expr.rkt
index 35902b2..207a27f 100644
--- a/beautiful-racket-demo/basic-demo-3/expr.rkt
+++ b/beautiful-racket-demo/basic-demo-3/expr.rkt
@@ -31,9 +31,13 @@
 (define-macro (b-func FUNC-ID ARG ...)
   #'(if (procedure? FUNC-ID)
         (let ([result (FUNC-ID ARG ...)])
-          (if (boolean? result)
-              (if result 1 0)
-              result))
+          (cond
+            [(number? result) (b-expr result)]
+            [(string? result) result]
+            [(boolean? result) (if result 1 0)]
+            [else
+             (raise-line-error
+              (format "unknown data type: ~v" result))]))
         (raise-line-error
          (format "expected ~a to be a function, got ~v"
                  'FUNC-ID FUNC-ID))))
diff --git a/beautiful-racket-demo/basic-demo-3/parser.rkt b/beautiful-racket-demo/basic-demo-3/parser.rkt
index 451282e..270b989 100644
--- a/beautiful-racket-demo/basic-demo-3/parser.rkt
+++ b/beautiful-racket-demo/basic-demo-3/parser.rkt
@@ -22,7 +22,7 @@ b-for : /"for" b-id /"=" b-expr /"to" b-expr [/"step" b-expr]
 b-next : /"next" b-id
 b-def : /"def" b-id /"(" ID [/"," ID]* /")" /"=" b-expr
 b-import : /"import" b-import-name
-@b-import-name : (ID | STRING)
+@b-import-name : ID | STRING
 b-expr : b-or-expr
 b-or-expr : [b-or-expr "or"] b-and-expr
 b-and-expr : [b-and-expr "and"] b-not-expr
@@ -35,4 +35,4 @@ b-expt : [b-expt ("^")] b-value
 @b-value : b-number | b-id | /"(" b-expr /")" | b-func
 b-func : ID /"(" b-expr [/"," b-expr]* /")"
 @b-number : INTEGER | DECIMAL
-b-repl : (b-statement | b-expr) (/":" [b-repl])*
\ No newline at end of file
+b-repl : (b-statement | b-expr) (/":" [b-repl])*