if absent put nil (Riaan) - Beginners

6 Aug 2008

      I have the following code
renderAttendeesOn: html
    self workSession attendees do: [:each | html text: each person
displayString] 
    		separatedBy: [html text:'; '.]
if there is no attendees for my worksession, it needs to display : NO
ABSENTEES.
Please assist.
-----Original Message-----
From: beginners-bounces@lists.squeakfoundation.org
[mailto:beginners-bounces@lists.squeakfoundation.org] On Behalf Of
beginners-request@lists.squeakfoundation.org
Sent: 05 August 2008 07:33 PM
To: beginners@lists.squeakfoundation.org
Subject: Beginners Digest, Vol 28, Issue 6
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When replying, please edit your Subject line so it is more specific
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Today's Topics:
1. true/false defined where? (Sean Allen)
   2. Re: true/false defined where? (Derek O'Connell)
   3. Re: true/false defined where? (Michael Rueger)
   4. Re: true/false defined where? (Sean Allen)
   5. Re: true/false defined where? (Randal L. Schwartz)
   6. Re: true/false defined where? (Sean Allen)
   7. Re: Problems getting started with OpenGL in Squeak (Ken G. Brown)
   8. Fighting again with MC (Giuseppe Luigi Punzi)
----------------------------------------------------------------------
Message: 1
Date: Tue, 5 Aug 2008 08:48:24 -0400
From: Sean Allen sean@monkeysnatchbanana.com
Subject: [Newbies] true/false defined where?
To: "A friendly place to get answers to even the most basic questions
    about	Squeak." beginners@lists.squeakfoundation.org
Message-ID:
    D11C3226-D6E5-4E84-A536-91AF90B689DC@monkeysnatchbanana.com
Content-Type: text/plain; charset=US-ASCII; format=flowed
where do true and false spring into existence?
i've been poking around and cant figure it out.
------------------------------
Message: 2
Date: Tue, 5 Aug 2008 13:53:18 +0100
From: "Derek O'Connell" doconnel@gmail.com
Subject: Re: [Newbies] true/false defined where?
To: "A friendly place to get answers to even the most basic questions
    about	Squeak." beginners@lists.squeakfoundation.org
Message-ID:
    1091398f0808050553o68e1afe8ybcc70c4083dc7429@mail.gmail.com
Content-Type: text/plain; charset=ISO-8859-1
Have a look in Kernel-Objects
On Tue, Aug 5, 2008 at 1:48 PM, Sean Allen sean@monkeysnatchbanana.com
wrote:
...
where do true and false spring into existence?
i've been poking around and cant figure it out.

Beginners mailing list
Beginners@lists.squeakfoundation.org
http://lists.squeakfoundation.org/mailman/listinfo/beginners
------------------------------
Message: 3
Date: Tue, 05 Aug 2008 14:54:45 +0200
From: Michael Rueger m.rueger@acm.org
Subject: Re: [Newbies] true/false defined where?
To: "A friendly place to get answers to even the most basic questions
    about	Squeak." beginners@lists.squeakfoundation.org
Message-ID: 48984D95.10509@acm.org
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Sean Allen wrote:
...
where do true and false spring into existence?
They have been around longer than some people on this mailing list ;-)
...
i've been poking around and cant figure it out.
true and false and some of the very few objects known to the VM and they 
where instantiated when the parent of all current images was created.
All images are basically cloned and not re-created from source, and 
that's why you don't see any initialization code for them, they just "are".
Hope this doesn't add to any confusion...
Michael
------------------------------
Message: 4
Date: Tue, 5 Aug 2008 09:09:01 -0400
From: Sean Allen sean@monkeysnatchbanana.com
Subject: Re: [Newbies] true/false defined where?
To: "A friendly place to get answers to even the most basic questions
    about	Squeak." beginners@lists.squeakfoundation.org
Message-ID:
    FA50326D-974B-48E4-A940-835C0664C75B@monkeysnatchbanana.com
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
On Aug 5, 2008, at 8:54 AM, Michael Rueger wrote:
...
Sean Allen wrote:
...
where do true and false spring into existence?
They have been around longer than some people on this mailing list ;-)
...
i've been poking around and cant figure it out.
true and false and some of the very few objects known to the VM and  
they where instantiated when the parent of all current images was  
created.
All images are basically cloned and not re-created from source, and  
that's why you don't see any initialization code for them, they just  
"are".
Hope this doesn't add to any confusion...
How is this for a confusing answer... it both does and doesnt.
I have a feeling the secret to unraveling that confusion comes from  
this:
'true and false and some of the very few objects known to the VM'
does that mean that I can't go and find these variables anywhere? that  
they arent true
global variables they are some sort of special global?
------------------------------
Message: 5
Date: Tue, 05 Aug 2008 07:52:50 -0700
From: merlyn@stonehenge.com (Randal L. Schwartz)
Subject: Re: [Newbies] true/false defined where?
To: Sean Allen sean@monkeysnatchbanana.com
Cc: "A friendly place to get answers to even the most basic questions
    about	Squeak." beginners@lists.squeakfoundation.org
Message-ID: 86pron3459.fsf@blue.stonehenge.com
Content-Type: text/plain; charset=us-ascii
...
...
...
...
...
"Sean" == Sean Allen sean@monkeysnatchbanana.com writes:
Sean> I have a feeling the secret to unraveling that confusion comes from
this:
Sean> 'true and false and some of the very few objects known to the VM'
Sean> does that mean that I can't go and find these variables anywhere? that
Sean> they arent true global variables they are some sort of special global?
If you explore "Smalltalk specialObjectsArray", you'll see a special list of
variables that both the VM and the Smalltalk code have to agree on in order
to
run.  For example, if a primitive wants to return "false", it has to
know what the rest of the Smalltalk image considers the sole instance
of the "False" class.
These items are established in
"SystemDictionary>>#recreateSpecialObjectsArray", the first version of which
had to be executed essentially "by hand" on the first VM (either the early
versions of Smalltalk 76 or 80).  Since then, this special array has gotten
its initial values by running it in an already running system, so the first
few entries there (nil, false, true) are in fact clones of clones of clones
of
the original handcrafted objects.  Of course, there's code on the VM side
that
knows the precise order of this magical array, and this is what allows them
to
communicate, so you can't just add new things here or change the ordering
without building a corresponding new VM.
-- 
Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095
merlyn@stonehenge.com URL:http://www.stonehenge.com/merlyn/
Smalltalk/Perl/Unix consulting, Technical writing, Comedy, etc. etc.
See http://methodsandmessages.vox.com/ for Smalltalk and Seaside discussion

------------------------------

Message: 6
Date: Tue, 5 Aug 2008 11:20:46 -0400
From: Sean Allen sean@monkeysnatchbanana.com
Subject: Re: [Newbies] true/false defined where?
To: Randal L. Schwartz merlyn@stonehenge.com
Cc: "A friendly place to get answers to even the most basic questions
    about	Squeak." beginners@lists.squeakfoundation.org
Message-ID:
    E74A1274-5E03-45A9-A674-31B05C202363@monkeysnatchbanana.com
Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes

On Aug 5, 2008, at 10:52 AM, Randal L. Schwartz wrote:

>>>>>> "Sean" == Sean Allen sean@monkeysnatchbanana.com writes:
>
> Sean> I have a feeling the secret to unraveling that confusion comes  
> from  this:
>
> Sean> 'true and false and some of the very few objects known to the  
> VM'
>
> Sean> does that mean that I can't go and find these variables  
> anywhere? that
> Sean> they arent true global variables they are some sort of special  
> global?
>
> If you explore "Smalltalk specialObjectsArray", you'll see a special  
> list of
> variables that both the VM and the Smalltalk code have to agree on  
> in order to
> run.  For example, if a primitive wants to return "false", it has to
> know what the rest of the Smalltalk image considers the sole instance
> of the "False" class.
>
> These items are established in
> "SystemDictionary>>#recreateSpecialObjectsArray", the first version  
> of which
> had to be executed essentially "by hand" on the first VM (either the  
> early
> versions of Smalltalk 76 or 80).  Since then, this special array has  
> gotten
> its initial values by running it in an already running system, so  
> the first
> few entries there (nil, false, true) are in fact clones of clones of  
> clones of
> the original handcrafted objects.  Of course, there's code on the VM  
> side that
> knows the precise order of this magical array, and this is what  
> allows them to
> communicate, so you can't just add new things here or change the  
> ordering
> without building a corresponding new VM.

Thanks for the pointer of where to explore and the background info.
In a couple days when I've had time to review and digest hopefully it  
will all make sense.

------------------------------

Message: 7
Date: Tue, 5 Aug 2008 10:39:19 -0600
From: "Ken G. Brown" kbrown@mac.com
Subject: Re: [Newbies] Problems getting started with OpenGL in Squeak
To: beginners@lists.squeakfoundation.org
Message-ID: <p06240402c4be2f7ab3a6@[10.0.1.200]>
Content-Type: text/plain; charset="us-ascii"

At 5:00 AM -0700 8/5/08, beginners-request@lists.squeakfoundation.org
apparently wrote:
>Date: Mon, 4 Aug 2008 14:48:26 -0700 (PDT)
>From: Nick Ager nick.ager@gmail.com
>Subject: Re: [Newbies] Problems getting started with OpenGL in Squeak
>To: beginners@lists.squeakfoundation.org
>Message-ID: 18820572.post@talk.nabble.com
>Content-Type: text/plain; charset=us-ascii
>
>
> >> Not sure this will help in your case, but just for information, there
are
>some plugin naming convention i>> ssues, the generated name does not always
>match the plugin name.
>
>>> internal plugin B3DEnginePlugin generated as Squeak3D
>
>the list produced by executing: "SmalltalkImage current listBuiltinModules"
>includes B3DAcceleratorPlugin. Could that be a synonym for "Squeak3D"?
Where
>is the mapping between the names?
>
>Looking again at the Croquet image, when showing a 3D window,
>"SmalltalkImage current listLoadedModules" includes B3DAcceleratorPlugin
and
>opengl32.dll
>
>Although I'm not sure this gets me closer to solving my problem...
>--
>View this message in context:
http://www.nabble.com/Problems-getting-started-with-OpenGL-in-Squeak-tp18752
922p18820572.html
>Sent from the Squeak - Beginners mailing list archive at Nabble.com.

If you load VMMaker and look in the 'VMMaker' category (package?), you will
see InterpreterPlugin class. The plugins are subclasses of this or
SmartSyntaxInterpreterPlugin.

The #InterpreterPlugin class has the moduleName instance variable. Some of
the plugins have class methods that return their name eg.
B3DAcceleratorPlugin has moduleName
    ^'B3DAcceleratorPlugin'

Not exactly sure where the moduleName gets set in other plugins.

Maybe someone else can tell how this works in more detail.

Ken G. Brown

------------------------------

Message: 8
Date: Tue, 05 Aug 2008 19:23:16 +0200
From: Giuseppe Luigi Punzi glpunzi@lordzealon.com
Subject: [Newbies] Fighting again with MC
To: "A friendly place to get answers to even the most basic questions
    about	Squeak." beginners@lists.squeakfoundation.org
Message-ID: 48988C84.10506@lordzealon.com
Content-Type: text/plain; charset="iso-8859-1"

Hi all,

Is the second time I'm having  troubles with simple changes to my 
package :S, and I can't figure out what I'm doing bad.

I'm working in a little app. I did it 2 minor changes writing some 
comments on Doc side of a class, one line on a method commented and so on.

Now, I'm trying to commit to my MC repository, and I get an:
Error: Subscript Out Of Bounds: 1

Following the debugger, seems the error is in:
foreignExtensionMethodsForClass: aClass
    ^ (self foreignExtensionCategoriesForClass: aClass)
        gather: [:cat | (aClass organization listAtCategoryNamed: cat)
                          collect: [:sel | self referenceForMethod: sel 
ofClass: aClass]]

where 'cat' is nil. But I don't know wich Category is this.

Some advice?

Note: Debug Report attached. cid:part1.02090207.00060503@lordzealon.com