Beginners August 2008

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60 participants
58 discussions

LargeIntegers atRandom more analysis
by Jerome Peace 11 Aug '08

11 Aug '08

LargeIntegers atRandom more analysis Hi Tim, Hi Randal Nothing like a little coding to go >From confident Ignorance: http://www.sacred-texts.com/tarot/pkt/img/ar00.jpg To humble Understanding: http://www.sacred-texts.com/tarot/pkt/img/ar01.jpg Playing and trying to debug my notion of large integer randoms, show that what I had proposed as a decomposition for the problem had bigger problems than I first thought. I did not get far enough to blame the generator. But ran into problems with convincing myself that with the decomposition I could get an evenly distributed probility for numbers from 1 to large n. I still believe that LargeInteger has the responsibility for giving back a good random. Along the way, or actually while I slept, I realized that the limitation is not necessarily in the generator but in the combining of the floating point and large integer in nextInt: . This is a problem. 24 factorial + 1000000 = (24 factorial * 1.0) will answer true. while ( 24 factorial - (24 factorial * 1.0 ) asInteger ) = 0 will answer false. There is a truncation difficulty with floats. I say difficulty rather than bug because it is not spec'ed to work otherwise. With this knowledge some relief can be had by gening up a large random number and treating it as a fraction. So a step towards the solution would be to define: LargePositiveInteger>> atRandom: aGenerator "Answer a random integer from 1 to self picked from aGenerator. To handle Large integers the arithmetic must use integer arithmetic. This will work if the generator is up to multiple uses." | nHigits numerator radix maxSigBits nextLargeInteger denominator | maxSigBits := 53 . " aGenerator class maxSignificantBits. " radix := radix := ( 2 raisedTo: maxSigBits ) . nHigits := (self highBit // maxSigBits ) + 1 . numerator := 0 . nextLargeInteger := [ ( aGenerator next * radix ) asInteger ] . nHigits timesRepeat: [ numerator := numerator * radix + nextLargeInteger value ] . denominator := radix raisedTo: nHigits . ^ self * numerator // denominator + 1 . This leaves the problem of the usable/reusalbe generator to be solved. I would also want a way for the generator classes to return maxSigBits. The pleasing thing about the above code is that with the method in place I did not have to change anything else to get atRandom to work better. So #atRandom: proves itself a useful hook. This solution passes the oddity test. That is a very low threshold test. This is also a fragile solution. There are probably some places that it fails. It would be interesting to find a test that it couldn't pass. Then use that to vet the next iteration of the fix. Yours in curiosity and service, --Jerome Peace

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chess game opening algorithm follow-up
by Daniel Lewis 08 Aug '08

08 Aug '08

As a follow-up to the question of how one would open up Chess in Squeak, I combined all of your answers into a single algorithm. Here it is... Squeak chess opening algorithm 1) open squeak 2) download (v 1.10) of chess.st.gz from http://map1.squeakfoundation.org/package/cb19b6f1-e371-47b2-b814-4bad079d0f… 3) unzip it 4) drag Chess.st into main window and select fileIn entire file 5) right click in the main window, in the pop-up menu go to Project, click on open 6) in the menu click on workspace 7) type "ChessMorph new openInWorld" (no quotes) 8) highlight the above text, right click and select do-it from menu 9) chess should now be running Thanks guys!

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Is it generally considered better practice for an object to access its own variables via its getter methods?
by Andy Burnett 08 Aug '08

08 Aug '08

I noticed that the Seaside tutorial has code such as: html div class: 'menu'; with: self menuComponent. Whereas the Scriptaculous demo code does things like this: html paragraph id: 'position'; with: position. I.e. they didn't bother adding (or using) a getter for position. Who is right, or doesn't it matter, or is there another reason why it would be written differently? cheers AB

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How do I run Chess?
by Daniel Lewis 08 Aug '08

08 Aug '08

Hello, I would like to explore Squeak but am unable to do even the simplest thing: running a program. I have spent literally hours trying to figure this out, browsing on the web and just playing with the application but I don't know how to make Chess.st run graphically so I can play the game. I've looked at the code and all but still don't understand how to make it run. Could you help me please? Daniel Lewis

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Re: Tim's Fix for LargeIntger>>AtRandom
by Jerome Peace 08 Aug '08

08 Aug '08

[Newbies] Re: Tim's Fix for LargeIntger>>AtRandom was: [Newbies] Re: What's wrong with this statement? *** >Cerebus cerebus2 at gmail.com >Tue Aug 5 00:31:42 UTC 2008 > >Interestingly, UUIDGenerator creates 16 bytes of random using Random >one bit at a time. > >I suspect there are entropy issues all through the image. UUIDGenerator uses its own generator. It reRandomizes its seed after going thru 100,000 bits. So it won't won't run out. Currently, for atRandom we use the community shared generator. In any event it is not the main deal. The problem was LargeInt was not using enough random bits. That was a critical bug because you weren't getting what you thought you were to get, one of n equally random numbers. The objection Randal raised is that now it is using too many. That's IMO a red herring. There are always ways of generating more random bits. It's not directly part of this problem. If need be could be solved similarly to the way UUIDGenerator solves it. Partial progress counts, and squeak is made for incremental programming. When you get a fix you like post it to the mantis report and I'll look at it. Yours in curiosity and service, --Jerome Peace ><snipped see earlier posts in thread> ***

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a simple Morph
by Stephan Janosch 07 Aug '08

07 Aug '08

Hi there! I have some difficulties to create a morph, which shows me simply all elements of an array inside that morph. my morph has an instance var called myArray. now the morph should simply show the contents of myArray. and here my confusion start. I don't want to reprogram PluggableListMorph. But I don't get this thing to use myArray. I guess PluggableListMorph want's to have a model. Or? So I should the MVC stuff, or? I did some morphic tutorials, but none of these showed me, how to build a more complex morph. There are rectangles, drag and drop and so on. But there is nothing like: here is a collection, now show me all elements of that collection inside a morph (as a list). In my understanding, I would build a classic MVC-triple. But as i understood Morphic, there is no need for classic MVC anymore. So I am badly confused. My realisation so far: BorderedMorph subclass: #MenschMorph instanceVariableNames: 'liste' classVariableNames: '' poolDictionaries: '' category: 'UserObjects' initialize | c m| super initialize. self extent: 50@50. self position: 50@50. self color: Color white. self liste: #('name' 'alter' 'huhu'). c := 1. liste do: [:each | m := TextMorph new openInWorld. m position: self position + (1@c*10). c:= c+1. self addMorph: m. ]. Now i would write some manipulation stuff for 'liste'. I would delete all the TextMorphs and simply redraw them, but with my manipulated list as new 'input'. And that feels damn wrong to me. How to proceed? My goal should be a Morph, which shows me simply the contens of a list. The Morph should update itself, when i manipulate the list. Classic MVC for me. Am I right? So long, Stephan

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Best place to ask Smalltalk questions?
by Sean Allen 07 Aug '08

07 Aug '08

If I have beginner Smalltalk questions. What is the best forum for asking those? Here even if they aren't squeak specific? Some other mailing list?

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Can Seaside applications support REST style calls?
by Andy Burnett 06 Aug '08

06 Aug '08

I imagine the answer is yes, so the problem should probably be "how can I get seaside to support rest calls?" I am thinking of building some components, of a site, in Flash. Ideally, I would like the user to be able to submit form data through the Flash object. So, I need to provide some URL handling on the server side. Is there a object I should use for this? It is possible that this relates to my other query. In the Seaside tutorial image there is Lightbox test. The Dispatcher doesn't seem to have a registered RootObject for this entry, and yet it still works. As far as I can tell, it just calls the SULightBoxTest. However, I can't work out how to register an object in that way. Cheers AB

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if absent put nil (Riaan)
by Riaan van Aarde (SpeCon Eng.) 06 Aug '08

06 Aug '08

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(a)lists.squeakfoundation.org [mailto:beginners-bounces@lists.squeakfoundation.org] On Behalf Of beginners-request(a)lists.squeakfoundation.org Sent: 05 August 2008 07:33 PM To: beginners(a)lists.squeakfoundation.org Subject: Beginners Digest, Vol 28, Issue 6 Send Beginners mailing list submissions to beginners(a)lists.squeakfoundation.org To subscribe or unsubscribe via the World Wide Web, visit http://lists.squeakfoundation.org/mailman/listinfo/beginners or, via email, send a message with subject or body 'help' to beginners-request(a)lists.squeakfoundation.org You can reach the person managing the list at beginners-owner(a)lists.squeakfoundation.org When replying, please edit your Subject line so it is more specific than "Re: Contents of Beginners digest..." 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(a)monkeysnatchbanana.com> Subject: [Newbies] true/false defined where? To: "A friendly place to get answers to even the most basic questions about Squeak." <beginners(a)lists.squeakfoundation.org> Message-ID: <D11C3226-D6E5-4E84-A536-91AF90B689DC(a)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(a)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(a)lists.squeakfoundation.org> Message-ID: <1091398f0808050553o68e1afe8ybcc70c4083dc7429(a)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(a)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(a)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(a)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(a)lists.squeakfoundation.org> Message-ID: <48984D95.10509(a)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(a)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(a)lists.squeakfoundation.org> Message-ID: <FA50326D-974B-48E4-A940-835C0664C75B(a)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(a)stonehenge.com (Randal L. Schwartz) Subject: Re: [Newbies] true/false defined where? To: Sean Allen <sean(a)monkeysnatchbanana.com> Cc: "A friendly place to get answers to even the most basic questions about Squeak." <beginners(a)lists.squeakfoundation.org> Message-ID: <86pron3459.fsf(a)blue.stonehenge.com> Content-Type: text/plain; charset=us-ascii >>>>> "Sean" == Sean Allen <sean(a)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(a)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(a)monkeysnatchbanana.com> Subject: Re: [Newbies] true/false defined where? To: Randal L. Schwartz <merlyn(a)stonehenge.com> Cc: "A friendly place to get answers to even the most basic questions about Squeak." <beginners(a)lists.squeakfoundation.org> Message-ID: <E74A1274-5E03-45A9-A674-31B05C202363(a)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(a)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(a)mac.com> Subject: Re: [Newbies] Problems getting started with OpenGL in Squeak To: beginners(a)lists.squeakfoundation.org Message-ID: <p06240402c4be2f7ab3a6(a)[10.0.1.200]> Content-Type: text/plain; charset="us-ascii" At 5:00 AM -0700 8/5/08, beginners-request(a)lists.squeakfoundation.org apparently wrote: >Date: Mon, 4 Aug 2008 14:48:26 -0700 (PDT) >From: Nick Ager <nick.ager(a)gmail.com> >Subject: Re: [Newbies] Problems getting started with OpenGL in Squeak >To: beginners(a)lists.squeakfoundation.org >Message-ID: <18820572.post(a)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(a)lordzealon.com> Subject: [Newbies] Fighting again with MC To: "A friendly place to get answers to even the most basic questions about Squeak." <beginners(a)lists.squeakfoundation.org> Message-ID: <48988C84.10506(a)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>

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true/false defined where?
by Sean Allen 06 Aug '08

06 Aug '08

where do true and false spring into existence? i've been poking around and cant figure it out.

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Beginners August 2008