Creating a Form Editor

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Creating a Form Editor

bprior
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?

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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Re: Creating a Form Editor

stephane ducasse
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....)
>
> _______________________________________________
> Beginners mailing list
> [hidden email]
> http://lists.squeakfoundation.org/mailman/listinfo/beginners
>

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Re: Creating a Form Editor

Marcus Denker
In reply to this post by bprior

On 05.01.2007, 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."
>
.....

> 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?
>

The Smalltalk as documented in Adele's books is a very old version. A  
lot has changed. Forms, for example, have been extended to support  
color. And the interface
for instance creation has been changed, as you have seen.

In general, the goal of Squeak was (should be, used to be) not to re-
create a 100% Smalltalk-80 compatible system, but to transcend  
Smalltalk... sadly not much has been
archieved, and the sytem even contains a lot of the old MVC code that  
is not used anymore (and slightly broken in many cases, as code not  
used rots). The Form editor,
for example, seems to only work in MVC and not Morphic.

        Marcus
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