instance methods are sent to objects: (10@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@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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