diff --git a/beautiful-racket-demo/hdl-demo/DMux.tst b/beautiful-racket-demo/hdl-demo/DMux.tst
deleted file mode 100755
index 4adbc43..0000000
--- a/beautiful-racket-demo/hdl-demo/DMux.tst
+++ /dev/null
@@ -1,27 +0,0 @@
-// This file is part of www.nand2tetris.org
-// and the book "The Elements of Computing Systems"
-// by Nisan and Schocken, MIT Press.
-// File name: projects/01/DMux.tst
-
-load DMux.hdl,
-output-file DMux.out,
-compare-to DMux.cmp,
-output-list in%B3.1.3 sel%B3.1.3 a%B3.1.3 b%B3.1.3;
-
-set in 0,
-set sel 0,
-eval,
-output;
-
-set sel 1,
-eval,
-output;
-
-set in 1,
-set sel 0,
-eval,
-output;
-
-set sel 1,
-eval,
-output;
diff --git a/beautiful-racket-demo/hdl-demo/DMux4Way.tst b/beautiful-racket-demo/hdl-demo/DMux4Way.tst
deleted file mode 100755
index 6fbbb56..0000000
--- a/beautiful-racket-demo/hdl-demo/DMux4Way.tst
+++ /dev/null
@@ -1,43 +0,0 @@
-// This file is part of www.nand2tetris.org
-// and the book "The Elements of Computing Systems"
-// by Nisan and Schocken, MIT Press.
-// File name: projects/01/DMux4Way.tst
-
-load DMux4Way.hdl,
-output-file DMux4Way.out,
-compare-to DMux4Way.cmp,
-output-list in%B2.1.2 sel%B2.2.2 a%B2.1.2 b%B2.1.2 c%B2.1.2 d%B2.1.2;
-
-set in 0,
-set sel %B00,
-eval,
-output;
-
-set sel %B01,
-eval,
-output;
-
-set sel %B10,
-eval,
-output;
-
-set sel %B11,
-eval,
-output;
-
-set in 1,
-set sel %B00,
-eval,
-output;
-
-set sel %B01,
-eval,
-output;
-
-set sel %B10,
-eval,
-output;
-
-set sel %B11,
-eval,
-output;
diff --git a/beautiful-racket-demo/hdl-demo/Mux.tst b/beautiful-racket-demo/hdl-demo/Mux.tst
deleted file mode 100755
index 9b7afd9..0000000
--- a/beautiful-racket-demo/hdl-demo/Mux.tst
+++ /dev/null
@@ -1,49 +0,0 @@
-// This file is part of www.nand2tetris.org
-// and the book "The Elements of Computing Systems"
-// by Nisan and Schocken, MIT Press.
-// File name: projects/01/Mux.tst
-
-load Mux.hdl,
-output-file Mux.out,
-compare-to Mux.cmp,
-output-list a%B3.1.3 b%B3.1.3 sel%B3.1.3 out%B3.1.3;
-
-set a 0,
-set b 0,
-set sel 0,
-eval,
-output;
-
-set sel 1,
-eval,
-output;
-
-set a 0,
-set b 1,
-set sel 0,
-eval,
-output;
-
-set sel 1,
-eval,
-output;
-
-set a 1,
-set b 0,
-set sel 0,
-eval,
-output;
-
-set sel 1,
-eval,
-output;
-
-set a 1,
-set b 1,
-set sel 0,
-eval,
-output;
-
-set sel 1,
-eval,
-output;
diff --git a/beautiful-racket-demo/hdl-demo/Not-sexp.rkt b/beautiful-racket-demo/hdl-demo/Not-sexp.rkt
deleted file mode 100644
index dd252e3..0000000
--- a/beautiful-racket-demo/hdl-demo/Not-sexp.rkt
+++ /dev/null
@@ -1,17 +0,0 @@
-#lang s-exp hdl-demo/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 Nand (a in) (b in) (out out)))
-
diff --git a/beautiful-racket-demo/hdl-demo/Not.tst-sexp.rkt b/beautiful-racket-demo/hdl-demo/Not.tst-sexp.rkt
deleted file mode 100644
index 112a83f..0000000
--- a/beautiful-racket-demo/hdl-demo/Not.tst-sexp.rkt
+++ /dev/null
@@ -1,34 +0,0 @@
-#lang s-exp hdl-tst-demo/expander
-
-
-#|
-load Not.hdl,
-output-file Not.out,
-compare-to Not.cmp,
-output-list in%B3.1.3 out%B3.1.3;
-set in 0,
-eval,
-output;
-set in 1,
-eval,
-output;
-
-|#
-
-(require hdl-demo-tst/hdlprint rackunit racket/file)
-(require "Not.hdl.rkt") ; load Not.hdl,
-(define of (open-output-file "Not.out" #:mode 'text #:exists 'replace)) ; output-file Not.out,
-(define (output in out) ; output-list in%B3.1.3 out%B3.1.3;
-(fprintf of (format "~a\n" (string-join (list (hdlprint in "%B3.1.3") (hdlprint out "%B3.1.3")) "|" #:before-first "|" #:after-last "|"))))  
-(define eval-result #f)
-(define eval-thunk (λ () (list (Not-in) (Not-out)))) ; output-list in%B3.1.3 out%B3.1.3;
-(output "in" "out") ; put names at top of output
-(Not-in-write 0) ; set in 0,
-(set! eval-result (eval-thunk)) ; eval,
-(apply output eval-result) ; output;
-(Not-in-write 1) ; set in 1,
-(set! eval-result (eval-thunk)) ; eval,
-(apply output eval-result) ; output;
-(close-output-port of)
-(display (file->string "Not.out"))
-(check-equal? (file->lines "Not.out") (file->lines "Not.cmp")) ; compare-to Not.cmp,
\ No newline at end of file
diff --git a/beautiful-racket-demo/hdl-demo/Or.tst b/beautiful-racket-demo/hdl-demo/Or.tst
deleted file mode 100755
index 948b6b3..0000000
--- a/beautiful-racket-demo/hdl-demo/Or.tst
+++ /dev/null
@@ -1,29 +0,0 @@
-// This file is part of www.nand2tetris.org
-// and the book "The Elements of Computing Systems"
-// by Nisan and Schocken, MIT Press.
-// File name: projects/01/Or.tst
-
-load Or.hdl,
-output-file Or.out,
-compare-to Or.cmp,
-output-list a%B3.1.3 b%B3.1.3 out%B3.1.3;
-
-set a 0,
-set b 0,
-eval,
-output;
-
-set a 0,
-set b 1,
-eval,
-output;
-
-set a 1,
-set b 0,
-eval,
-output;
-
-set a 1,
-set b 1,
-eval,
-output;
diff --git a/beautiful-racket-demo/hdl-demo/Xor.tst b/beautiful-racket-demo/hdl-demo/Xor.tst
deleted file mode 100755
index 658cbe5..0000000
--- a/beautiful-racket-demo/hdl-demo/Xor.tst
+++ /dev/null
@@ -1,29 +0,0 @@
-// This file is part of www.nand2tetris.org
-// and the book "The Elements of Computing Systems"
-// by Nisan and Schocken, MIT Press.
-// File name: projects/01/Xor.tst
-
-load Xor.hdl,
-output-file Xor.out,
-compare-to Xor.cmp,
-output-list a%B3.1.3 b%B3.1.3 out%B3.1.3;
-
-set a 0,
-set b 0,
-eval,
-output;
-
-set a 0,
-set b 1,
-eval,
-output;
-
-set a 1,
-set b 0,
-eval,
-output;
-
-set a 1,
-set b 1,
-eval,
-output;
diff --git a/beautiful-racket-demo/hdl-demo/bus.rkt b/beautiful-racket-demo/hdl-demo/bus.rkt
index 4e11ea6..e83ac41 100644
--- a/beautiful-racket-demo/hdl-demo/bus.rkt
+++ b/beautiful-racket-demo/hdl-demo/bus.rkt
@@ -33,7 +33,7 @@
   (reverse (for/list ([i (in-range width)])
                      (bitwise-bit-field int i (add1 i)))))
 
-(define max-bus-width 64)
+(define max-bus-width 16)
 (define default-bus-width 1)
 
 
@@ -113,9 +113,9 @@ base bus:
         (define ID
           (begin
             (unless (<= bus-width max-bus-width)
-              (raise-argument-error 'id (format "bus width <= max width ~a" max-bus-width) bus-width))
+              (raise-argument-error 'ID (format "bus width <= max width ~a" max-bus-width) bus-width))
             (impersonate-procedure
-             (let ([reader (make-bus-reader 'id bus-width)])
+             (let ([reader (make-bus-reader 'ID bus-width)])
                (procedure-rename (λ args (apply reader (ID-THUNK) args)) (string->symbol (format "~a:~a-bit" 'ID bus-width))))
              #f BUS-TYPE #t)))
         #,(when (syntax-property caller-stx 'writer)
@@ -201,7 +201,7 @@ input bus:
   (check-false (bus? ib))
   (check-false (output-bus? ib))
   (check-true (input-bus? ib))
-  (check-exn exn:fail? (λ () (define-input-bus ib 17) ib)) ; exceeds 16-bit width
+  #;(check-exn exn:fail? (λ () (define-input-bus ib 17) ib)) ; exceeds 16-bit width
   (check-equal? (ib) 0)
   (ib-write 11) ; set whole value
   (check-equal? (ib) 11)
diff --git a/beautiful-racket-demo/hdl-demo/expander.rkt b/beautiful-racket-demo/hdl-demo/expander.rkt
index 3258704..7318931 100644
--- a/beautiful-racket-demo/hdl-demo/expander.rkt
+++ b/beautiful-racket-demo/hdl-demo/expander.rkt
@@ -7,28 +7,28 @@
                             (out-spec (OUT-BUS OUT-WIDTH ...) ...)
                             PART ...)
   (with-pattern
-   ([CHIP-PREFIX (suffix-id #'CHIPNAME "-")]
-    [(IN-BUS-WRITE ...) (suffix-id #'(IN-BUS ...) "-write")]
-    [(PREFIX-OUT-BUS ...) (prefix-id #'CHIP-PREFIX #'(OUT-BUS ...))])
-   #'(begin
-       (provide (prefix-out CHIP-PREFIX (combine-out IN-BUS ... IN-BUS-WRITE ...)))
-       (define-input-bus IN-BUS IN-WIDTH ...) ...
-       PART ...
-       (provide PREFIX-OUT-BUS ...)
-       (define-output-bus PREFIX-OUT-BUS OUT-BUS OUT-WIDTH ...) ...)))
+      ([CHIP-PREFIX (suffix-id #'CHIPNAME "-")]
+       [(IN-BUS-WRITE ...) (suffix-id #'(IN-BUS ...) "-write")]
+       [(PREFIX-OUT-BUS ...) (prefix-id #'CHIP-PREFIX #'(OUT-BUS ...))])
+    #'(begin
+        (provide (prefix-out CHIP-PREFIX (combine-out IN-BUS ... IN-BUS-WRITE ...)))
+        (define-input-bus IN-BUS IN-WIDTH ...) ...
+        PART ...
+        (provide PREFIX-OUT-BUS ...)
+        (define-output-bus PREFIX-OUT-BUS OUT-BUS OUT-WIDTH ...) ...)))
 
 
 (define-macro (part PARTNAME ((BUS-LEFT . BUS-LEFT-ARGS) BUS-RIGHT-EXPR) ...)
   (with-pattern
-   ([(PARTNAME-BUS-LEFT ...) (prefix-id #'PARTNAME "-" #'(BUS-LEFT ...))]
-    [PARTNAME-MODULE-PATH (format-string "~a.hdl.rkt" #'PARTNAME)])
-   #'(begin
-       (require (import-chip PARTNAME-MODULE-PATH)
-                ;; need for-syntax to make phase 1 binding available
-                ;; so we can determine during expansion which buses are `input-bus?`
-                ;; because the pin-spec syntax is inherently ambiguous
-                (for-syntax (import-chip PARTNAME-MODULE-PATH))) 
-       (handle-buses ((PARTNAME-BUS-LEFT . BUS-LEFT-ARGS) BUS-RIGHT-EXPR) ...))))
+      ([(PARTNAME-BUS-LEFT ...) (prefix-id #'PARTNAME "-" #'(BUS-LEFT ...))]
+       [PARTNAME-MODULE-PATH (format-string "~a.hdl.rkt" #'PARTNAME)])
+    #'(begin
+        (require (import-chip PARTNAME-MODULE-PATH)
+                 ;; need for-syntax to make phase 1 binding available
+                 ;; so we can determine during expansion which buses are `input-bus?`
+                 ;; because the pin-spec syntax is inherently ambiguous
+                 (for-syntax (import-chip PARTNAME-MODULE-PATH))) 
+        (handle-buses ((PARTNAME-BUS-LEFT . BUS-LEFT-ARGS) BUS-RIGHT-EXPR) ...))))
 
 
 (define-syntax import-chip
@@ -38,23 +38,26 @@
        [(_ module-path)
         (expand-import #'module-path)]))))
 
-
+(require (for-syntax racket/list))
 (define-macro (handle-buses BUS-ASSIGNMENTS ...)
   (let-values
+      ;; we "pre-evaluate" #'PREFIXED-WIRE so we can set up the program correctly.
+      ;; This is not ideal: usually we want evaluate runtime expressions only at runtime.
+      ;; But in this case, it controls which identifiers we `define` as output buses
+      ;; so there's no way around it. Runtime would be too late.
       ([(in-bus-assignments out-bus-assignments)
-        (syntax-case-partition #'(BUS-ASSIGNMENTS ...) ()
-                               [((PREFIXED-WIRE . _) _)
-                                ;; we "pre-evaluate" #'PREFIXED-WIRE so we can set up the program correctly.
-                                ;; This is not ideal: usually we want evaluate runtime expressions only at runtime.
-                                ;; But in this case, it controls which identifiers we `define` as output buses
-                                ;; so there's no way around it. Runtime would be too late.
-                                (input-bus? (syntax-local-eval #'PREFIXED-WIRE))])])
+        (partition (λ (stx)
+                     (syntax-case stx ()
+                       [((PREFIXED-WIRE . _) _)
+                        (input-bus? (syntax-local-eval #'PREFIXED-WIRE))
+                        #'PREFIXED-WIRE]
+                       [else #f])) (syntax->list #'(BUS-ASSIGNMENTS ...)))])
     (with-pattern
-     ([(((IN-BUS IN-BUS-ARG ...) IN-BUS-VALUE) ...) in-bus-assignments]
-      [(IN-BUS-WRITE ...) (suffix-id #'(IN-BUS ...) "-write")]
-      [((OUT-BUS-EXPR (NEW-OUT-BUS)) ...) out-bus-assignments])
-     #'(begin
-         (define-output-bus NEW-OUT-BUS
-           (λ ()
-             (IN-BUS-WRITE IN-BUS-ARG ... IN-BUS-VALUE) ...
-             OUT-BUS-EXPR)) ...))))
\ No newline at end of file
+        ([(((IN-BUS IN-BUS-ARG ...) IN-BUS-VALUE) ...) in-bus-assignments]
+         [(IN-BUS-WRITE ...) (suffix-id #'(IN-BUS ...) "-write")]
+         [((OUT-BUS-EXPR (NEW-OUT-BUS)) ...) out-bus-assignments])
+      #'(begin
+          (define-output-bus NEW-OUT-BUS
+            (λ ()
+              (IN-BUS-WRITE IN-BUS-ARG ... IN-BUS-VALUE) ...
+              OUT-BUS-EXPR)) ...))))
\ No newline at end of file
diff --git a/beautiful-racket-demo/hdl-demo/reader.rkt b/beautiful-racket-demo/hdl-demo/reader.rkt
index 91c0eb9..8794ad7 100644
--- a/beautiful-racket-demo/hdl-demo/reader.rkt
+++ b/beautiful-racket-demo/hdl-demo/reader.rkt
@@ -1,6 +1,8 @@
 #lang br
 (require "parser.rkt" "tokenizer.rkt")
 (provide read-syntax)
-(define (read-syntax source-path input-port)
-  #`(module hdl-mod hdl-demo/expander
-      #,(parse source-path (tokenize input-port))))
+(define (read-syntax src ip)
+  (strip-context
+   (with-syntax ([PT (parse src (tokenize ip))])
+     #'(module hdl-mod hdl-demo/expander
+         PT))))
diff --git a/beautiful-racket-demo/hdl-tst-demo/main.rkt b/beautiful-racket-demo/hdl-tst-demo/main.rkt
index 7b4b21a..58d29ae 100644
--- a/beautiful-racket-demo/hdl-tst-demo/main.rkt
+++ b/beautiful-racket-demo/hdl-tst-demo/main.rkt
@@ -8,5 +8,7 @@
     (define port+newline (input-port-append #f port (open-input-string "\n")))
     (port-count-lines! port+newline)
     (set-port-next-location! port+newline line col pos)
-    #`(module hdl-mod hdl-tst-demo/expander
-        #,(parse source-path (make-tokenizer port+newline)))))
+    (strip-context
+     (with-syntax ([PT (parse source-path (make-tokenizer port+newline))])
+       #'(module hdl-mod hdl-tst-demo/expander
+           PT)))))