[Newbies] Creating a Form Editor
stephane ducasse
stephane.ducasse at free.fr
Fri Jan 5 07:49:36 UTC 2007
instance methods are sent to objects:
(10 at 100) x
x is an instance method sent to a point
@ is an instance method sent to 10
Now have a look at the class side (press the button class) on the
class Form
apparently there is a method extent: aPoint
This method is a method that will be executed when a class receives
the message extent:
Not that conceptually
Form new extent: aPoint
apparently there is no instance method name extent:
but if you try (Form new setExtent: 100 at 100 depth: 1) you will get
a form
but set* may indicate that this is a method that you should not
direcly invoke (as explained in the book of Beck or Smalltalk by
Example)
Stef
On 5 janv. 07, at 05:56, Bruce Prior wrote:
> Hi Squeakers,
>
> I have been reading Adele Goldberg's classic text, "Smalltalk-80
> The Interactive Programming Environment," and came across this in
> Chapter 7, "How to make Pictures."
>
> Adele states, "Create a Form Editor by evaluating an expression of
> the form,
>
> (Form new extent: 300 @ 400) edit"
>
> It didn't work for me in Squeak 3.8 (on my Macintosh).
>
> Further down, Adele says, "The message edit can be sent to any
> instance of Form." But when I checked with my browser I found that
> Form has a class method extent: but not an instance method extent:.
>
> So I tried (Form extent: 300 @ 400) edit and the Form Editor
> appeared as desired. Is this because Smalltalk and Squeak are
> different somehow, or is there a mistake in the text, or?
Squeak has 26 years more :)
> If the text is correct, then I still don't fully appreciate the
> difference between class and instance methods.
>
> Bruce Prior (still looking for "ah - ha!" and I think it's close....)
>
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