Beginners February 2008

beginners@lists.squeakfoundation.org

56 participants
54 discussions

Using RoelTyper
by Peter Goodall 25 Feb '08

25 Feb '08

Hi All, I am using the Squeak dev image sq3.10-7159dev08.02.1.image, and cannot work out how to invoke the RoelTyper. I can find illustrations on VisualWorks, and acclamations in Squeak forums, but have not found any instructions, screen-grabs etc. It is loaded with unit-tests, into the image I am using. Can someone help me out here please. Thanks, --Peter G -- View this message in context: http://www.nabble.com/Using-RoelTyper-tp15673134p15673134.html Sent from the Squeak - Beginners mailing list archive at Nabble.com.

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The bouncing sound
by polishookm 25 Feb '08

25 Feb '08

I"m finding that with [Rectangle forward by 5] [Rectangle bounce silence] the rectangle eventually collides with the top of the world and bounces off in the opposite direction - with no sound ... the bounce is silent. However, this script [Rectangle forward by JoyStick's upDown * 8] [Rectangle bounce silence] doesn't allow the Rectangle bounce silently off the edge of the world. In this case, when the rectangle reaches the top of the world, it makes a bouncing sound. The exact sound can be selected in the [Rectangle bounce silence] tile. But selecting 'silence' as the sound doesn't seem to work. Am I missing something obvious? Shouldn't it be possible to silence the bounce?

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Old local changes on a new image
by Juan José Evangelista 24 Feb '08

24 Feb '08

Hello I'm working on an app hosted in monticello. I made a heavy work on my classes in an image during the last three months. Some days ago, I need to create a new image and load my code from monticello. Everything goes ok, but I lose all my local version history. When I click on versions, I only see changes from the creation of the new image. I want to know if there are some way to incorporate all my changes made to the old image to the new one. Thanks in advance, and I hope you can understand my english. ----------------------------------------------------------------------- Para estar bien, primero hay que aprender a estar.

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Talk to me of Browsers
by Jeffrey Straszheim 23 Feb '08

23 Feb '08

Howdy, I am a relative Squeak newcomer and I'm trying to get a sense of what sorts of options there are for me to work with. My question tonight regards browsers. I am running the 3.9 (7067) image and am using the default browser it comes with. However, I've loaded up some other images and they include a different browser that seems to support Traits (whatever they are exactly) and more refactoring tools. However, after some brief experiments that browser seemed a bit buggy to me -- I couldn't browse instance variables for instance, and asking for the 'senders' of a message threw an exception. On these mailing lists I've seen folks talk about: the "Traits Browser", the "Omni Browser", and so on. On SqueakMap I see something called the Refactoring Browser that requires something else called "AST". Can someone give me a breakdown of the currently supported browsers and why I might choose one over the other. I don't mind advice of the sort: "Use this one!" That would be great. Thanks in advance. -- Jeffrey Straszheim http://straszheim.50megs.com

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The long way, and how to avoid it. A coding example.
by Jerome Peace 23 Feb '08

23 Feb '08

The long way, and how to avoid it. Hi all, Here is a problem that appeared on the #squeak irc channel today (22 Feb 2008) Matthew solved it brilliantly as I was plodding with speed ups I knew I could do. Below is a series of modified examples with time profiles (from an old turn of the century iMac.) It illustrates how to have fun with optimizations and iterations on a project. The intermediate steps might prove useful in other contexts. [ | img col x y | img := ImageMorph defaultForm asFormOfDepth: 32 . y := 0. [y < (img height)] whileTrue: [ x := 0 . [x < (img width)] whileTrue: [ col := (img colorAt: x@y) . img colorAt: x@y put: (TranslucentColor r: (col red) g: (col green) b: (col blue) alpha: 0.7). x := x + 1. ] . y := y + 1. ] . img asMorph openInWorld. ] timeToRun "1152" "-------" [ | img col x y | img := ImageMorph defaultForm asFormOfDepth: 32 . y := 0. [y < (img height)] whileTrue: [ x := 0 . [x < (img width)] whileTrue: [ img colorAt: x@y put: ( (img colorAt: x@y) alpha: 0.7). x := x + 1. ] . y := y + 1. ] . img asMorph openInWorld. ] timeToRun "930" "-------" [ | img | img := ImageMorph defaultForm asFormOfDepth: 32 . (0 to: (img height)) do: [ :y | ( 0 to: (img width)) do: [ :x | img colorAt: x@y put: ( (img colorAt: x@y) alpha: 0.7) ] ] . img asMorph openInWorld. ] timeToRun "934" "-------" [ | img picker poker | img := ImageMorph defaultForm asFormOfDepth: 32 . [ | img picker poker transColor | img := ImageMorph defaultForm asFormOfDepth: 32 . picker := BitBlt bitPeekerFromForm: img . poker := BitBlt bitPokerToForm: img . (0 to: (img height)) do: [ :y | ( 0 to: (img width)) do: [ :x | transColor := ( Color colorFromPixelValue: ( picker pixelAt: x@y) depth: 32 ) alpha: 0.7 . poker pixelAt: (x@y) put: ( img pixelValueFor: transColor ) ] . ] . img asMorph openInWorld. ] timeToRun "376" "-------" [ | img destForm | img := ImageMorph defaultForm asFormOfDepth: 32 . destForm := img allocateForm: (img width)@(img height). destForm copyBits: img at: 0@0 translucent: 0.7. destForm asMorph openInWorld. ] timeToRun " 4" "-------" wiz 2/22/2008 17:11 Ok. what do we have here. Here are five examples of the same behavior. A 32 bit form is obtained and processed to obtain a 0.7 translucent version of the same form. The translucent form is displayed on the screen. The first example (I modified the img to avoid an external file reference.) was submitted by a user who noted it was slow. ( If he was using a substantially larger picture he would have noticed an even bigger delay. The first image takes about a second per postage stamp sized picture on my old iMac. ) The second pass optimizes some of the innerloop by not breaking the color down into its componects but just making the whole color transparent. This saves about 25% of the time. The third pass simplifies the code by enumerating the height and width implicitly. This doesn't save any time ( it may even take a tad longer). But it eliminates several lines of code. Which makes what is going on clearer. The fourth pass optimizes the picking and poking of pixels by seting them up explicitly. This means we are back to explicitly turning pixels to colors and back again. The reward for our efforts is a further 60% reduction in time. Now there should be some way to just have a form copy itself and pick up a fixed alpha along the way. I just haven't gotten smart enough to know how. Ah. Matthew has pasted it as an annotation to imaginators original paste. http://paste.lisp.org/display/56338#2 Giving us a fifth example. Letting bitBlt do all the work is clearly a winner. A 99% speedup. Next step is to see why .pngs take so long to load. And that is left as a execise for the reader. Yours in curiosity and service, --Jerome Peace ____________________________________________________________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ

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Recap: How to empty a collection
by Blake 21 Feb '08

21 Feb '08

I've been following this debate with some interest, but I think it's gone beyond a noob discussion. Is there a noob answer to this question? There ought to be. I'm sort of leaning toward: Q. How do you empty a collection. A. You don't, you replace it with a new instance. Q. What if you have references to the collection in multiple places? A. Wrap the collection in another class, and reference that. ??

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Re: [Newbies] The bouncing sound
by Scott Wallace 21 Feb '08

21 Feb '08

Hi, Mark, What you're hearing is not a sound associated with the "bounce" but rather a sound associated with an object hitting the "fence". The "fence" is a feature that makes a "forward" command which would take an object beyond the edge of its container result in the the object's jiggling back into the field of view, accompanied by a special "fence" sound. The intent is to reduce the incidence of "runaways" when beginners write scripts using "forward" which rapidly take an object beyond an edge of its container, thus making it disappear. When using "bounce", it's advisable to *disable* the "fence", because the interactions between the logic of the two features can produce confusing results. Use the world's "playfield options" menu to disable the fence. However, without the fence, in your student's example, there seem to be situations in which the the paddle overshoots the boundary and disappears. I think you could eliminate these situations by slightly reducing the factor used in the paddle's script1. In the olpc/etoys image, there's an added preference that suppresses the fence *sound*, thus allowing the fence feature to be used to keep an object within its container's bounds but without the annoyance of hearing the "fence" sound. But this is not in 3.9. These two features -- a container's "fence" feature and the ability for a moving object to request "bounce" -- have always, unhappily, been somewhat in conflict. For the "next" system we expect to have a much more harmonious and consistent and understandable way of offering such things. BTW, unless you have a compelling reason to be using 3.9, and particularly if tile-scripting is the main focus of your class I suggest that you have your students use a Squeakland image rather than a 3.9 or 3.10, simply because extensive enhancements, fixes, and documentation for tile-scripting ("etoys") are available in the Squeakland images. But if you do decide to switch, it's probably best to wait a short while until the "new Squeakland image" gets released. This will be based on the OLPC-etoys image, which is the system in which all the advances in etoys have been made over the past 18 months -- hundreds of bug-fixes, feature-enhancements, performance improvement, example projects, tutorials, and other documentation, plus a large user community. Cheers, -- Scott On Feb 20, 2008, at 8:29 PM, polishookm wrote: > Scott, > > Here's a project file that demonstrates the problem. I'm working in > the most recent ver. of Squeak from www.squeak.org (just downloaded > a few days ago) .... 3.9-final-7067 > > When I activate the script with the object controlled by a joystick, > the first few times it hits the top of the world and it's silent - > all is well. But at some point, after 3 or 4 or 5 collisions, it's > no longer silent. > > All help much appreciated and thanks very much in advance for > looking at the project (made by a student in the class I'm teaching). > > Ab, > > Mark > > > > Scott Wallace wrote: >> Hi, polishookm, >> >> I cannot reproduce the phenomenon you describe in any image I have >> close to hand -- not in Squeak 3.9, not in Squeakland3.8-05, and >> not in the OLPC etoys image. (Can anyone else?) >> >> What version of Squeak are you using? If it's 3.10, I'll leave it >> for other 3.10 users to track this down, since I don't have a copy >> of 3.10 handy. >> >> Otherwise, perhaps you could email me a copy of a project of yours >> which exhibits this symptom... >> >> >> Cheers, >> >> -- Scott >> >> >> >> On Feb 20, 2008, at 6:38 PM, polishookm wrote: >> >>> I"m finding that with >>> >>> [Rectangle forward by 5] >>> [Rectangle bounce silence] >>> >>> the rectangle eventually collides with the top of the world and >>> bounces off in the opposite direction - with no sound ... the >>> bounce is silent. >>> >>> However, this script >>> >>> [Rectangle forward by JoyStick's upDown * 8] >>> [Rectangle bounce silence] >>> >>> doesn't allow the Rectangle bounce silently off the edge of the >>> world. In this case, when the rectangle reaches the top of the >>> world, it makes a bouncing sound. The exact sound can be selected >>> in the [Rectangle bounce silence] tile. But selecting 'silence' as >>> the sound doesn't seem to work. >>> >>> Am I missing something obvious? Shouldn't it be possible to >>> silence the bounce? >>> >>> >>> _______________________________________________ >>> Beginners mailing list >>> Beginners(a)lists.squeakfoundation.org >>> http://lists.squeakfoundation.org/mailman/listinfo/beginners >> > > -- > 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(a)mail.montclair.edu > > <GLPong.002.pr>

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[Election 2008] Nominations end tomorrow! Final call...
by goran＠krampe.se 21 Feb '08

21 Feb '08

Hi all! The nomination period for this years election of the Squeak Foundation board WILL END tomorrow, on the 22nd february, hey, let's say at 23:59:59 UTC to be precise. :) So it is high time to speak up unless you already have done so! We have 11 candidates so far: Bert Freudenberg (serving on the board currently) Yoshiki Ohshima (serving on the board currently) Craig Latta (serving on the board currently) Tim Rowledge (serving on the board currently) Andrew P. Black (serving on the board currently) Matthew Fulmer Igor Stasenko Tansel Ersavas Giovanni Corriga Edgar J. De Cleene Randal L. Schwartz Having met 5 in person, worked with 2, chatted regularly with another 2 and of course corresponded quite a bit with the rest - my take is that we have a really good and strong lineup this year! All details and status for the election can be tracked at: http://wiki.squeak.org/squeak/6025 The next phase is the campaigning period. During this period the candidates should ideally present themselves with an article on SqP and the community can ask questions, either there or in followup discussions on squeak-dev. I also urge you all to look at the 10 questions we have cooked up for the candidates and if you feel some important question is missing - email me in private and I will (if I think it is a good thing) put it in the last 5 "open slots". First 5 served, then it is full! Deadline for sending me extra questions is the 24th. Candidates will answer (or not!) the questions from the 25th and onward by posting to squeak-dev. Feel free to discuss at length of course, the posts from the candidates will be added by me to the Q&A page so that all answers can be seen in one place. IMPORTANT: In order to vote - be sure to confirm that you have an account on http://people.squeakfoundation.org and that your email address is up to date. If you are not already registered on the site do so as soon as possible. Include information about your participation in the Squeak community to aid everyone in determining your appropriate certification. If you have misplaced your people.squeakfoundation.org password there is a link on the login page to allow you to reset it. When the voting period starts all voters will receive an email with instructions and a link to the voting website. regards, Göran

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is 0.1 a Float or a ScaledDecimal ?
by cdrick 21 Feb '08

21 Feb '08

I have another interrogation. Please take it as a student/newbie whatever question. I think 0.1 should be considered as a ScaledDecimal so that we could write 0.1 asFraction and have 1/10... To achieve that, there is a method that the Parser call... Number class >> readFrom: aStream which call: Number class>>readRemainderOf: integerPart from: aStream base: base withSign: sign which call: Number class>>readScaledDecimal: integerPart fractionPart: fractionPart digits: fractionDigits base: base sign: sign from: aStream ... What's interesting as a newbie perspective is the way I found these interesting methods... - only debug "0.1 asFraction" doesn't help, because it's hapening at "parse time"... I could have searched for selector containing "scaleddecimal" with cmd+shift+w but I did not... - Instead, as I knew it was related to Parser or Scanner, I looked in these class, then find Scanner scan: aStream. So I did: Scanner new scan: ('0.0123' readStream). "and the debut it" What these methods say is basically: 0.1234 evaluate as a Float and 0.1234s4 evaluated as a scaled decimal (because of s). IMvHO, I think at least decimal up to say scale 4 should be a scaled decimal... What do you think ? I have no idea of performance concerns... so I'll be pleased to have any knowledgeable insights :) Thanks a lot Cédrick

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Re: Beginners Digest, Vol 22, Issue 9
by Andy Burnett 20 Feb '08

20 Feb '08

@Yoshiki (and everyone else) Thanks very much for the suggestions about using the self halt and dragging onto a workspace - that is very helpful. The E-Toy Outliner is a small example application - not sure if it is in all images. Try searching for Outliner in the classes. I am hoping to extend it so that it can save data to a web server etc. It will be an interesting test as my knowledge develops. I found another solution to getting a handle on an object that was dragged from a flap. If I inspect the object and then execute something like Temp1 := self (in the inspector bottom pane), I then have a handle on it via a global variable. This also led me to learn that Smalltalk removeKey: Temp1 - let's me tidy up the dictionary. Finally, I have started a blog called http://learningsmalltalk.blogspot.com The idea is that it will capture my 'hmms' and 'ahhs' as I go through the process. I only mention this in case it is of use/interest to other beginners. Cheers AB

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Beginners February 2008