[etoys-dev] SQ-903 - Object displayed name does not always match name used to refer to object in scripts

[Scott Wallace]

On Mar 1, 2011, at 11:36 AM, Bert Freudenberg wrote:

> I hope Scott will chime in here, but I would guess that the world's presenter should be consulted:
> 
> World presenter allExtantPlayers collect: [:each | each uniqueNameForReference -> each externalName]
> 
> - Bert -

*CHIME*

As Bert says, it's the "presenter" object who can produce the lists of players known to a project.  The broadest list -- and presumably the right one to use in the case under discussion -- includes not only players whose morphs are in the submorph tree but also players referenced by scripts of any players whose morphs are in the tree; get such a list by sending the tongue-twisting message #reallyAllExtantPlayersNoSort to the presenter.

So if you know that a project has a player named 'Cat', in a textual script you can obtain a reference to that player using the code along the lines of:

	catPlayer := ActiveWorld presenter reallyAllExtantPlayersNoSort detect:
		[:p | p costume externalName = 'Cat'] ifNone: [nil].
	catPlayer ifNotNil: [  <proceed to do something to or with catPlayer...>  ]

  -- Scott


> On 01.03.2011, at 11:28, Ricardo Moran wrote:
> 
>> 
>> On Tue, Mar 1, 2011 at 3:05 PM, Steve Thomas <sthomas1 at gosargon.com> wrote:
>> Ricardo,
>> 
>> Thanks, actually what I need is to get the reference to the object from the External Name.
>> 
>> The problem is that two or more objects could have the same external name. However, if you're sure only one object has a given external name you can get its reference by implementing the following method in the class side of Player:
>> 
>> withExternalName: aString
>>  ^ (World findDeepSubmorphThat: [:each | each player externalName = aString] ifAbsent: []) player
>> 
>> And then you can get the reference from a script by sending: 
>> 
>> (Player withExternalName: 'Texto')
>> 
>> I really don't know if there is a better way of doing this, but keep in mind that my "solution" is just a hack that goes through all the morphs in the world looking for the player with the given external name.
>> 
>> I hope this helps :)
>> Richo
>>  
>> 
>> What I am trying to do is something similar to Learn Programming with Robots by Stephane Ducasse.  One of my goals is to find a way to provide a transition for kids from Etoys to Squeak and for me to play around and have fun ;)   In looking a at Ducasse's book, I am not really sure what value it adds to kids learning other than showing them the textual syntax of squeak as opposed to the tile version (except the some of the later chapters which introduce the browser, some debugging with halt, etc). Also some of the textual descriptions do not seem as effective or likely to be used by kids as some things that might be done in Etoys.
>> 
>> I really need to think about what for ?Computational Thinking? habits/experiences I want kids to have and how to create an Etoys that can facilitate learning them.
>> 
>> I think, this will take me quite a while  (but I'm having fun ;).
>> 
>> In any case 
>> 
>> Stephen
>> 
>> On Tue, Mar 1, 2011 at 9:34 AM, Ricardo Moran <richi.moran at gmail.com> wrote:
>> Hi Steve,
>> 
>> I don't think this is a bug. If I understood correctly, the name used to reference an object in a script is not supposed to be the same as the one displayed on the screen but a unique name that identifies only this object in the World. An object's external name can change at any time but the references to this object must remain consistent in all scripts.
>> 
>> I'm not sure what you're trying to do, but you can get an object's displayed name by sending #externalName to the object. See the attached project for an example.
>> 
>> Cheers,
>> Richo
>> 
>> 
>> On Tue, Mar 1, 2011 at 2:51 AM, Steve Thomas <sthomas1 at gosargon.com> wrote:
>> See: http://tracker.squeakland.org/browse/SQ-903
>> 
>> If you change the name of an object, the name used to reference it in a script (via show code textually) does not change.
>> So how do I reference the name of the player (as displayed on the screen) in a script?
>> 
>> script4
>> 	| t1 t2 p1 selector |
>> 	p1 := Text3.
>> 	t1 := Command1 getCharacters.
>> 	t2 := 5.
>> 	selector := (t1 , ':') asSymbol.
>> 	p1 perform: selector with: t2
>> 
>> In this above example I had a Text object where the screen showed its name (on page 2) as Text3, but when I used its characters tile in another Text object's script, it used the name Text4 in the text version of that script?
>> 
>> Stephen
>> 
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>> 
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>> 
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