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Improve class section.

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Eli Barzilay 2013-07-16 03:44:26 -04:00
parent 8f295f4e68
commit c99ac1be7e
1 changed files with 15 additions and 1 deletions
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@ -445,7 +445,7 @@ vec ; => #(1 2 3 4)
;; 8. Classes and Objects
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Create a class fish%
;; Create a class fish% (-% is idomatic for class bindings)
(define fish%
(class object%
(init size) ; initialization argument
@ -465,9 +465,23 @@ vec ; => #(1 2 3 4)
(new fish% [size 10]))
;; Use `send' to call an object's methods
(send charlie get-size) ; => 10
(send charlie grow 6)
(send charlie get-size) ; => 16
;; `fish%' is a plain "first class" value, which can get us mixins
(define (add-color c%)
(class c%
(init color)
(super-new)
(define my-color color)
(define/public (get-color) my-color)))
(define colored-fish% (add-color fish%))
(define charlie2 (new colored-fish% [size 10] [color 'red]))
(send charlie2 get-color)
;; or, with no names:
(send (new (add-color fish%) [size 10] [color 'red]) get-color)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; 9. Macros
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;