Add the implementation of 1d and 2d table

Author: ramsayleung

chapter3/1d-table.rkt

@@ -0,0 +1,36 @@
+#lang racket
+
+(define (make-table)
+  (mcons '*table* '()))
+
+(define (assoc key records)
+  (cond ((null? records) false)
+        ((equal? key (mcar (mcar records)))
+         (mcar records))
+        (else (assoc key (mcdr records)))))
+
+;;; O(N)
+(define (lookup key table)
+  (let ((record (assoc key (mcdr table))))
+    (if record
+        (mcdr record)
+        false)))
+
+(define (insert! key value table)
+  (let ((record (assoc key (mcdr table))))
+    (if record
+        (set-mcdr! record value)
+        (set-mcdr! table (mcons (mcons key value) (mcdr table)))))
+  'ok)
+
+(module+ test
+  (require rackunit)
+
+  (test-case "Test for 1 dimensional table"
+             (define 1dt (make-table))
+             (check-false (lookup 'no-exist-key 1dt))
+             (insert! 'name 'Jon 1dt)
+             (check-equal? (lookup 'name 1dt) 'Jon)
+             )
+  )
+(provide make-table insert! lookup assoc)

chapter3/2d-table.rkt

@@ -0,0 +1,47 @@
+#lang racket
+(require "1d-table.rkt")
+
+(define (make-table)
+  (let ((local-table (mcons '*table* '())))
+    (define (lookup key-1 key-2)
+      (let ((subtable (assoc key-1 (mcdr local-table))))
+        (if subtable
+            (let ((record (assoc key-2 (mcdr subtable))))
+              (if record
+                  (mcdr record)
+                  false))
+            false)))
+
+    (define (insert! key-1 key-2 value)
+      (let ((subtable (assoc key-1 (mcdr local-table))))
+        (if subtable
+            (let ((record (assoc key-2 (mcdr subtable))))
+              (if record
+                  (set-mcdr! record value)
+                  (set-mcdr! subtable (mcons (mcons key-2 value)
+                                             (mcdr subtable)))))
+            (set-mcdr! local-table (mcons
+                                    (mcons key-1
+                                           (mcons (mcons key-2 value) '()))
+                                    (mcdr local-table)))))
+      'ok)
+    (define (dispatch m)
+      (cond ((eq? m 'lookup-proc) lookup)
+            ((eq? m 'insert-proc!) insert!)
+            (else (error "Unknown Operation -- TABLE" m))))
+    dispatch))
+
+
+(module+ test
+  (require rackunit)
+
+  (test-case "Test for 2d table"
+             (define operation-table (make-table))
+             (define get (operation-table 'lookup-proc))
+             (define put (operation-table 'insert-proc!))
+             (check-false (get 'math '+))
+             (put 'math '+ 43)
+             (check-false (get 'math '*))
+             (check-equal? (get 'math '+) 43)
+             )
+  )