[Etoys] EllipseMorph and sibling instance

[polishookm]

Hi Scott,

Thanks for the explanation. I'm going to see if I can make the tutorials 
you suggest. I agree they would be helpful .....

> AFAIK, it's fine to have an all-scripts tool open as you create,  
> delete, rename, and otherwise manipulate objects and scripts; I'm not  
> aware of situations where it "misses" anything, but if you can  
> describe a sequence of steps leading to such a situation, it would be  
> helpful.
I'll report further on this. I have a feeling that what you've explained 
is the answer (and that's all material that should be presented simply 
in a tutorial style).

> (But I presume that people interested in "siblings" will have read the  
> contents of the "All Scripts" help-flap that is obtained by clicking  
> on the ? in the all-scripts tool.)

I missed this but have read it now and it's really helpful and perhaps 
also a roadmap of sorts for the simple tutorials ....

Thanks again,

Mark


Scott Wallace wrote:
> On Apr 13, 2008, at 8:20 AM, polishookm wrote:
>
>   
>> To answer my own question, I think what I'm observing is noted  
>> below. If
>> someone could comment that what I'm describing is how things work,  
>> that
>> would be great.
>>     
>
> Hi, Mark,
>
> Basically, your observations are correct, but please see the comments  
> after #9 and #10.
>
>
>   
>> 1. I make an EllipseMorph
>> 2. I open a viewer on the EllipseMorph and make a script. The script
>> belongs to a Player and the Player wears the EllipseMorph
>> 3. I bring up a halo on the EllipseMorph and click on the green
>> Duplicate icon.
>> 4. Now I have 2 Players, each of which wears an EllipseMorph
>> 5. Opening an AllScriptsTool provides for start/stop/stop control over
>> both Players
>>
>> 6. I make a RectangleMorph
>> 7. I open a viewer on the RectangleMorph and make a script. The script
>> belongs to a Player and the Player wears the EllipseMorph
>> 8. I bring up a halo on the RectangleMorph and shift-click on the  
>> green
>> Duplicate icon.
>> 9. Now I have 1 Player that's wearing (controlling) 2 RectangleMorphs.
>>     
>
> Almost...  What you now have are two *sibling players*, each of which  
> is a "Player" in its own right.  Each players wears its own separate  
> RectangleMorph as its costume.  The siblings are related in that they  
> have (and will forever have) the same "shape" (i.e. each has the same  
> list of "variables") and in that they share (and will forever share)  
> the same scripts.  If you add a variable to one of them, the same  
> variable will be added to the other.  If you add a script to one of  
> them, the same script will apply to the other one.
>
> But although siblings share a script, each sibling has its own private  
> "status" for that script, i.e. remembers separately whether the script  
> *as used by this instance* is "normal", "paused,", or "ticking", or  
> set to trigger on mouse-up, etc.; and what the tick-rate is.
>
> When using siblings, what's really happening underneath is that there  
> is a custom Player "Class" is created to bear the shared code, and the  
> siblings are individual "Instances" of that class.  "Class" and  
> "Instance" are among the most fundamental concepts of object-oriented  
> programming, but we don't much use the terms "class" and "instance" in  
> the etoys UI, nor in any documentation I'm aware of.  (A notorious  
> exception is the "all instances" checkbox in the all-scripts tool.)   
> We refer to "siblings" but don't have a formal term for the "class".   
> Hmm...  maybe the checkbox should read "all siblings" rather than "all  
> instances"...
>
>
>   
>> 10. Opening an AllScriptsTool provides for start/stop/stop control  
>> over
>> the Player that wears the 2 RectangleMorphs
>>     
>
> If the "all instances" box is not checked, you'll see the scripts for  
> only one player of each sibling group.  This will give you "control"  
> over the scripts of only one of the players.  If you want to be able  
> to "control" scripts for both of the siblings, make sure the "all  
> instances" checkbox is checked.
>
>
>   
>> I'm noticing that if AllScripts tool is on screen while  
>> EllipseMorphs or
>> RectangleMorphs are being duplicated, it won't then immediately pick  
>> up
>> on the fact that new Players exist. A new Player has to be run once  
>> and
>> then the AllScriptsTool knows it's there.
>>     
>
> Unless the "all instances" checkbox is checked, creation of new  
> siblings will typically not result in any noticeable change in the all- 
> scripts tool, since all the scripts of the new sibling will already be  
> represented by another instance in the tool.  Perhaps that's what  
> you're seeing.
>
> Also, if the "tickers only" box is checked, only scripts whose status  
> is "ticking" or "paused' are shown in the all-scripts tool.  This can  
> be another reason why the all-scripts tool may seem not to be "picking  
> up" on a change.
>
> AFAIK, it's fine to have an all-scripts tool open as you create,  
> delete, rename, and otherwise manipulate objects and scripts; I'm not  
> aware of situations where it "misses" anything, but if you can  
> describe a sequence of steps leading to such a situation, it would be  
> helpful.
>
> ----------
>
> I hope this helps some.  We are still woefully short of documentation  
> in this area and much about "siblings" is not particularly obvious.   
> (But I presume that people interested in "siblings" will have read the  
> contents of the "All Scripts" help-flap that is obtained by clicking  
> on the ? in the all-scripts tool.)
>
> A couple of nice, simple tutorial projects in Squeak about these  
> matters would be so very welcome...
>
> Cheers,
>
> -- Scott
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>   

-- 
Mark Polishook, D.M.A.
Technology Coordinator
Morehead Hall, Rm 132
Center for Academic Advising and Adult Learning
Montclair State University
Montclair, NJ 07043

(973)-655-7114
http://www.montclair.edu/AcademicAdvising/html
polishookm at mail.montclair.edu