Remove last of quasiquote style in OCaml to Racket notes.

Author: dvanhorn

langs/intro/bt.rkt

@@ -5,34 +5,36 @@
   (require rackunit))
 
 ;; type Bt =
-;; | `leaf
-;; | `(node ,Integer ,Bt ,Bt)
+;; | (leaf)
+;; | (node Integer Bt Bt)
+(struct leaf () #:prefab)
+(struct node (v l r) #:prefab)
 
 ;; Bt -> Boolean
 ;; Is the binary tree empty?
 (define (bt-empty? bt)
   (match bt
-    ['leaf #t]
-    [(cons 'node _) #f]))
+    [(leaf) #t]
+    [_ #f]))
 
 (module+ test
-  (check-equal? (bt-empty? 'leaf) #t)
-  (check-equal? (bt-empty? '(node 3
-                                  (node 7 leaf leaf)
-                                  (node 9 leaf leaf)))
+  (check-equal? (bt-empty? (leaf)) #t)
+  (check-equal? (bt-empty? (node 3
+                                 (node 7 (leaf) (leaf))
+                                 (node 9 (leaf) (leaf))))
                 #f))
 
 ;; Bt -> Natural
 ;; Compute the height of a binary tree
 (define (bt-height bt)
   (match bt
-    [`leaf 0]
-    [`(node ,_ ,left ,right)
+    [(leaf) 0]
+    [(node _ left right)
      (+ 1 (max (bt-height left)
                (bt-height right)))]))
 
 (module+ test
-  (check-equal? (bt-height 'leaf) 0)
-  (check-equal? (bt-height '(node 3 leaf leaf)) 1)
-  (check-equal? (bt-height '(node 2 leaf (node 1 leaf leaf)))
+  (check-equal? (bt-height (leaf)) 0)
+  (check-equal? (bt-height (node 3 (leaf) (leaf))) 1)
+  (check-equal? (bt-height (node 2 (leaf) (node 1 (leaf) (leaf))))
                 2))

www/notes/1/ocaml-to-racket.scrbl

@@ -1168,11 +1168,13 @@ also write modules without saving them in a file.  For example:
 
 @ex[
 (module bt racket
-  (provide bt-height)
+  (provide (all-defined-out))
+  (struct leaf () #:prefab)
+  (struct node (v l r) #:prefab)  
   (define (bt-height bt)
     (match bt
-      [`leaf 0]
-      [`(node ,_ ,left ,right)
+      [(leaf) 0]
+      [(node _ left right)
        (+ 1 (max (bt-height left)
                  (bt-height right)))])))
 ]
@@ -1185,7 +1187,7 @@ provided values:
 
 @ex[
 (require 'bt)
-(bt-height 'leaf)
+(bt-height (leaf))
 ]
 
 We could have also used the @tt{#lang racket} shorthand for
@@ -1214,29 +1216,32 @@ provide everything:
   (module+ test
     (require rackunit))
 
+  (struct leaf () #:prefab)
+  (struct node (v l r) #:prefab)  
+
   (define (bt-empty? bt)
     (match bt
-      ['leaf #t]
-      [(cons 'node _) #f]))
+      [(leaf) #t]
+      [_ #f]))
 
   (module+ test
-    (check-equal? (bt-empty? 'leaf) #t)
-    (check-equal? (bt-empty? '(node 3
-                                    (node 7 leaf leaf)
-                                    (node 9 leaf leaf)))
+    (check-equal? (bt-empty? (leaf)) #t)
+    (check-equal? (bt-empty? (node 3
+                                   (node 7 (leaf) (leaf))
+                                   (node 9 (leaf) (leaf))))
                   #f))
 
   (define (bt-height bt)
     (match bt
-      [`leaf 0]
-      [`(node ,_ ,left ,right)
+      [(leaf) 0]
+      [(node _ left right)
        (+ 1 (max (bt-height left)
                  (bt-height right)))]))
 
   (module+ test
-    (check-equal? (bt-height 'leaf) 0)
+    (check-equal? (bt-height (leaf)) 0)
     (code:comment "intentionally wrong test:")
-    (check-equal? (bt-height '(node 3 leaf leaf)) 2)))
+    (check-equal? (bt-height (node 3 (leaf) (leaf))) 2)))
 ]
 
 Requiring this module with make @racket[bt-height], but @emph{it will not run the tests}: