WeBlowg Side

3.3.1

Exersise 3.1
Exersise 3.2
Exersise 3.3
Exersise 3.4

3.3.3

テーブルの生成とアクセッサー

 (define (make-table)
   (let ((local-table (list '*table*)))
     (define (lookup key-1 key-2)
       (let ((subtable (assoc key-1 (cdr local-table))))
     (if subtable
         (let ((record (assoc key-2 (cdr subtable))))
           (if record
           (cdr record)
           #f))
         #f)))
     (define (insert! key-1 key-2 value)
       (let ((subtable (assoc key-1 (cdr local-table))))
     (if subtable
         (let ((record (assoc key-2 (cdr subtable))))
           (if record
           (set-cdr! record value)
           (set-cdr! subtable
                 (cons (cons key-2 value)
                   (cdr subtable)))))
         (set-cdr! local-table
               (cons (list key-1
                   (cons key-2 value))
                 (cdr local-table)))))
       'ok)
     (define (dispatch m)
       (cond ((eq? m 'lookup-proc) lookup)
         ((eq? m 'insert-proc!) insert!)
         (else (error "Unknown operation -- TABLE" m))))
     dispatch))
 
 (define operation-table (make-table))
 (define get (operation-table 'lookup-proc))
 (define put (operation-table 'insert-proc!))