[Tutor] Learning about callbaks

[Michael Bernhard Arp Sørensen]

Hi.

On Jan 2, 2008 6:36 PM, Alan Gauld <alan.gauld at btinternet.com> wrote:

> Can you modify the program *without modifying the classes* to use an
> ordinary function as the callback? Say this goodbye function:
>
> def goodbye():
>     print "goodbye world"
>
> This should not require more than 5 lines of new code and no changes
> to the
> existing code. It could be done in 3...
>

Like this?:

class UserInput:
    def __init__(self):
        pass

    def test_callback(self, this_callback):
        print "testing the callback"
        this_callback()

class Game:
    def __init__(self):
        self.ui = UserInput()

    def hello(self):
        print "hello world"

    def useUI(self):
        self.ui.test_callback(self.hello)

def goodbye():
    print "goodbye world"

g = Game()
g.useUI()
g.ui.test_callback(goodbye)

It took me a couple of minutes to understand your challenge. :-) Then I
remembered that "ui" is instantiated inside "g" and therefore callable with
the right parameter.

Thank you very, very much. I enjoy a good challenge.

-- 
Med venlig hilsen/Kind regards

Michael B. Arp Sørensen
Programmør / BOFH
I am /root and if you see me laughing you better have a backup.
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