diff --git a/beautiful-racket-lib/br/syntax.rkt b/beautiful-racket-lib/br/syntax.rkt
index fc29ee7..91cf581 100644
--- a/beautiful-racket-lib/br/syntax.rkt
+++ b/beautiful-racket-lib/br/syntax.rkt
@@ -28,11 +28,18 @@
   (syntax-case stx ()
     [(_ _proc _args)
      #'(let ([args _args])
-         (datum->syntax args
-                        (if (and (syntax? args) (list? (syntax-e args)))
-                            (for/list ([arg (in-list (syntax->list args))])
-                                      (datum->syntax arg (_proc (syntax->datum arg))))
-                            (error 'not-syntax-list))))]))
+         (unless (and (syntax? args) (list? (syntax-e args)))
+           (raise-argument-error 'map-syntax "not a syntax list"))
+         (for/list ([arg (in-list (syntax->list args))])
+                   (_proc arg)))]))
+
+(define-syntax (partition-syntax stx)
+  (syntax-case stx ()
+    [(_ _proc _args)
+     #'(let ([args _args])
+         (unless (and (syntax? args) (list? (syntax-e args)))
+           (raise-argument-error 'map-syntax "not a syntax list"))
+         (partition _proc (syntax->list args)))]))
 
 (define-syntax (filter-syntax stx)
   (syntax-case stx ()
diff --git a/beautiful-racket/br/demo/hdl/Nand.hdl.rkt b/beautiful-racket/br/demo/hdl/Nand.hdl.rkt
index 8655fa2..3139518 100644
--- a/beautiful-racket/br/demo/hdl/Nand.hdl.rkt
+++ b/beautiful-racket/br/demo/hdl/Nand.hdl.rkt
@@ -1,13 +1,19 @@
 #lang br
+(provide (prefix-out Nand- (all-defined-out)))
+(require "helper.rkt")
 
-(define+provide (Nand #:a a #:b b)
-  (if (< (+ a b) 2)
+(define a (make-input))
+(define b (make-input))
+
+
+(define (out)
+  (if (< (+ (a) (b)) 2)
       1
       0))
 
 (module+ test
   (require rackunit)
-  (check-equal? (Nand #:a 0 #:b 0) 1)
-  (check-equal? (Nand #:a 0 #:b 1) 1)
-  (check-equal? (Nand #:a 1 #:b 0) 1)
-  (check-equal? (Nand #:a 1 #:b 1) 0))
+  (check-equal? (begin (a 0) (b 0) (out)) 1)
+  (check-equal? (begin (a 0) (b 1) (out)) 1)
+  (check-equal? (begin (a 1) (b 0) (out)) 1)
+  (check-equal? (begin (a 1) (b 1) (out)) 0))
diff --git a/beautiful-racket/br/demo/hdl/Not-sexp.rkt b/beautiful-racket/br/demo/hdl/Not-sexp.rkt
new file mode 100644
index 0000000..861101d
--- /dev/null
+++ b/beautiful-racket/br/demo/hdl/Not-sexp.rkt
@@ -0,0 +1,16 @@
+#lang s-exp br/demo/hdl/expander
+
+#|
+CHIP Not {
+          IN in;
+          OUT out;
+             
+          PARTS:
+          Nand(a=in, b=in, out=out);
+}
+|#
+
+(chip-program Not
+              (in-spec in)
+              (out-spec out)
+              (part-spec (part Nand (a in) (b in) (out out))))
\ No newline at end of file
diff --git a/beautiful-racket/br/demo/hdl/Not.hdl.rkt b/beautiful-racket/br/demo/hdl/Not.hdl.rkt
index df87a41..e8034cd 100644
--- a/beautiful-racket/br/demo/hdl/Not.hdl.rkt
+++ b/beautiful-racket/br/demo/hdl/Not.hdl.rkt
@@ -4,10 +4,9 @@ CHIP Not {
           IN in;
           OUT out;
              
-             PARTS:
-             Nand(a=in, b=in, out=out);
-             
-             }
+          PARTS:
+          Nand(a=in, b=in, out=out);
+}
 
 
 
diff --git a/beautiful-racket/br/demo/hdl/Not2.hdl.rkt b/beautiful-racket/br/demo/hdl/Not2.hdl.rkt
deleted file mode 100644
index 757ccfb..0000000
--- a/beautiful-racket/br/demo/hdl/Not2.hdl.rkt
+++ /dev/null
@@ -1,38 +0,0 @@
-#lang racket
-#|
-
-CHIP Not {
-          IN in;
-          OUT out, outb;
-             
-             PARTS:
-             ;; each part has only as many args as wires in that part
-             Nand(a=in, b=in, out=nand-out); 
-             Fanout(in=nand-out, outa=out, outb=outb);
-             
-             }
-
-|#
-
-(require "helper.rkt" "helper-macro.rkt" (for-syntax "helper.rkt" racket/syntax racket/list))
-
-;; IN and OUT spec becomes provide spec, prefixed with chip name
-(provide (prefix-out Not- (combine-out in out outb))) 
-
-;; all IN and OUT pins are functions.
-
-(define in (make-input)) ; all inputs are made from the same function that holds state like a parameter.
-
-;; all outputs are computed at runtime.
-(require "Nand2.hdl.rkt" (for-syntax "Nand2.hdl.rkt"))
-(handle-part Nand2 [a in] [b in] [out nand-out])
-(require "Fanout.hdl.rkt" (for-syntax "Fanout.hdl.rkt"))
-(handle-part Fanout [in nand-out] [outa out] [outb outb])
-;(handle-require Fanout [in nand-out] [outa out] [outb outb])
-
-(module+ test
-  (require rackunit)
-  (in 1)
-  (check-equal? (out) 0)
-  (in 0)
-  (check-equal? (out) 1))
\ No newline at end of file
diff --git a/beautiful-racket/br/demo/hdl/expander.rkt b/beautiful-racket/br/demo/hdl/expander.rkt
index aa2d5f2..5362584 100644
--- a/beautiful-racket/br/demo/hdl/expander.rkt
+++ b/beautiful-racket/br/demo/hdl/expander.rkt
@@ -1,24 +1,44 @@
 #lang br
+(require "helper.rkt" (for-syntax racket/base racket/syntax "helper.rkt" racket/list racket/require-transform))
 (provide #%top-interaction #%module-begin #%app #%datum (all-defined-out))
 
+
 (define #'(chip-program _chipname
-                                  (pin-spec _input-pin ...)
-                                  (pin-spec _output-pin ...)
-                                  (part-spec (part _partname (_pin _val) ... (_lastpin _pinout)) ...))
-  #'(begin
-      (define+provide _chipname
-        (procedure-rename
-         (make-keyword-procedure
-          (λ (kws kw-args . rest)
-            (define kw-pairs (map cons kws kw-args))
-            (let ([_input-pin (cdr (assq (string->keyword (format "~a" '_input-pin)) kw-pairs))] ...)
-              (define _pinout (call-part _partname [_pin _val] ...)) ...
-              (values _output-pin ...)))) '_chipname))))
-
-
-(define #'(call-part _partname [_pin _val] ...)
-  (inject-syntax ([#'part-path (findf file-exists? (list (format "~a.hdl" (syntax->datum #'_partname)) (format "~a.hdl.rkt" (syntax->datum #'_partname))))]
-                  [#'(kw ...) (map (λ(pi) (string->keyword (format "~a" (syntax->datum pi)))) (syntax->list #'(_pin ...)))])
-                 #'(let ()
-                     (local-require (rename-in part-path [_partname local-name]))
-                     (keyword-apply local-name '(kw ...) (list _val ...) null))))
+                        (in-spec _input-pin ...)
+                        (out-spec _output-pin ...)
+                        (part-spec (part _partname (_pin _val) ... ) ...))
+  (with-syntax ([chip-prefix (format-id #'_chipname "~a-" #'_chipname)])
+    #'(begin
+        (provide (prefix-out chip-prefix (combine-out _input-pin ... _output-pin ...))) 
+        (define _input-pin (make-input)) ...
+        (handle-part _partname (_pin _val) ...) ...)))
+
+
+(define #'(handle-part _prefix [_suffix _arg] ...)
+  (with-syntax ([(prefix-suffix ...) (map (λ(s) (format-id s "~a-~a" #'_prefix s)) (syntax->list #'(_suffix ...)))]
+                [chip-module-path (datum->syntax #'_prefix (format "~a.hdl.rkt" (syntax->datum #'_prefix)))])
+    #'(begin
+        (require (import-chip chip-module-path) (for-syntax (import-chip chip-module-path)))
+        (handle-wires [prefix-suffix _arg] ...))))
+
+
+(define-syntax import-chip
+  (make-require-transformer
+   (λ (stx)
+     (syntax-case stx ()
+       [(_ module-path)
+        (expand-import #'module-path)]))))
+
+
+(define #'(handle-wires _wirearg-pair ...)
+  (let-values ([(in-wire-stxs out-wire-stxs)
+                (partition (λ(wirearg-pair-stx)
+                             (define wire-stx (car (syntax->list wirearg-pair-stx)))
+                             (input-wire? (syntax-local-eval wire-stx)))
+                           (syntax->list #'(_wirearg-pair ...)))])
+    (with-syntax ([([in-wire in-arg] ...) in-wire-stxs]
+                  [([out-wire out-arg] ...) out-wire-stxs])
+      #'(begin
+          (define (out-arg)
+            (in-wire (in-arg)) ...
+            (out-wire)) ...))))
\ No newline at end of file
diff --git a/beautiful-racket/br/demo/hdl/helper-macro.rkt b/beautiful-racket/br/demo/hdl/helper-macro.rkt
deleted file mode 100644
index 137f70a..0000000
--- a/beautiful-racket/br/demo/hdl/helper-macro.rkt
+++ /dev/null
@@ -1,35 +0,0 @@
-#lang racket/base
-(require (for-syntax racket/base racket/syntax "helper.rkt" racket/list))
-(provide (all-defined-out))
-
-
-(define-syntax (handle-require stx)
-  (syntax-case stx ()
-    [(_ prefix [suffix arg] ...)
-     (with-syntax ([(prefix-suffix ...) (map (λ(s) (format-id s "~a-~a" #'prefix s)) (syntax->list #'(suffix ...)))]
-                   [module-name (format "~a.hdl.rkt" (syntax->datum #'prefix))])
-       #'(begin
-           (local-require module-name (for-syntax module-name))
-           (handle-wires [prefix-suffix arg] ...)))]))
-
-
-(define-syntax (handle-part stx)
-  (syntax-case stx ()
-    [(_ prefix [suffix arg] ...)
-     (with-syntax ([(prefix-suffix ...) (map (λ(s) (format-id s "~a-~a" #'prefix s)) (syntax->list #'(suffix ...)))]
-                   [module-name (format "~a.hdl.rkt" (syntax->datum #'prefix))])
-       #'(begin
-           (require module-name (for-syntax module-name))
-           (handle-wires [prefix-suffix arg] ...)))]))
-
-
-(define-syntax (handle-wires stx)
-  (syntax-case stx ()
-    [(_ [wire arg] ...)
-     (let ()
-       (define-values (in-wires out-wires) (partition (λ(stx) (let ([wire (car (syntax->list stx))])
-                                                                (input-wire? (syntax-local-eval wire)))) (syntax->list #'([wire arg] ...))))
-       (with-syntax ([([in-wire in-arg] ...) in-wires]
-                     [([out-wire out-arg] ...) out-wires])
-         #'(begin
-             (define out-arg (λ () (in-wire (in-arg)) ... (out-wire))) ...)))]))
\ No newline at end of file
diff --git a/beautiful-racket/br/demo/hdl/helper.rkt b/beautiful-racket/br/demo/hdl/helper.rkt
index 4c828b8..ffb1c36 100644
--- a/beautiful-racket/br/demo/hdl/helper.rkt
+++ b/beautiful-racket/br/demo/hdl/helper.rkt
@@ -6,7 +6,7 @@
 
 (define (make-input)
   (impersonate-procedure 
-   (let ([val #f])
+   (let ([val 0])
      (λ ([arg #f])
        (if arg
            (set! val arg)
diff --git a/beautiful-racket/br/demo/hdl/parser.rkt b/beautiful-racket/br/demo/hdl/parser.rkt
index a88109c..f9c3a8a 100644
--- a/beautiful-racket/br/demo/hdl/parser.rkt
+++ b/beautiful-racket/br/demo/hdl/parser.rkt
@@ -1,10 +1,14 @@
 #lang brag
 
-chip-program : /"CHIP" chipname /"{" pin-spec pin-spec part-spec /"}"
+chip-program : /"CHIP" chipname /"{" in-spec out-spec part-spec /"}"
 
 @chipname : ID
 
-pin-spec : (/"IN" | /"OUT") pin [/"," pin]* /";"
+in-spec : pin-spec
+
+out-spec : pin-spec
+
+@pin-spec : (/"IN" | /"OUT") pin [/"," pin]* /";"
 
 @pin : ID