Squeak-dev March 2006

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instanceOf
by Corneanu Dan 04 Mar '06

04 Mar '06

How can I test if an object is an instance of a given class?

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Plopp and Teddy (was: An interesting presentation and discussion, maybe still is)
by David Faught 03 Mar '06

03 Mar '06

Andreas Raab wrote: >Avi Bryant wrote: >> From what I can tell it's a 3d modeling tool for kids based on the >> Teddy 3d sketching stuff (http://yap.jp.land.to/yas/pukiwiki.php?%5B% >> 5BPapers%2FTeddy%5D%5D). Am I close? :) >Close, but no cigar ;-) Plopp is a product based on the 3D painting >system that's also in Croquet which is quite a bit different from Teddy. >In Teddy, you draw an outline first and then you paint on the surface of >the 3D extrusion. In Plopp you paint the entire object at once. This >idea originated in the masters thesis of Jana Hintze at the games group >in Magdeburg (see >http://isgwww.cs.uni-magdeburg.de/games/projekte/kindervorlesung/jive.html). Both of these approaches are very easy to use, so they appeal to me :) And the method of "inflation" is very similar between the two. In the Croquet version of this system, there are frequently errors when the painted object doesn't have a strong continuous outline, and the Teddy flavor, which is still in Squeak 3.8 Wonderland, is fun, but not as easy to manipulate as I would like and has no export function. At the moment, I am using an external modeler (Art of Illusion) to create 3D models, but I would like to find an open-source 3D paint program similar to Tattoo ( http://www.terabit.nildram.co.uk/tattoo/ ) to complement this. One of the projects on my "someday" list is to make a specialized version of the Squeak Wonderland Pooh-painting that is easier to interact with and has better import/export capability. Or maybe develop a whole new version of this, similar to Takeo Igarashi's old Chameleon, only with Java and OpenGL for platform independence. As long as I'm daydreaming, it would be really nice to have cleaned up, usable versions of Takeo Igarashi's SmoothTeddy and Squirrel, which includes creating a model, painting it, and animating it, only maybe rewritten in Croquet ...

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[FileOut by Date]
by Steve Moffitt 03 Mar '06

03 Mar '06

I'm filing out classes to study -- they all seem to be sorted by category -- is it possible to get it to fileOut sorted by date easily ( I didn't see the option on the fileOut preferences ) . Thanks Steve

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RE: SqF feedback
by Peter Crowther 03 Mar '06

03 Mar '06

> From: stéphane ducasse > if you have some points that you would like to see happening > please mention it. Decide what, if anything, SqF wishes to do about the de-facto fragmentation of Squeak into different communities. I'm not sure how much of a mandate there is for this - I ran for the board based on wanting to reduce the fragmentation, and I came soundly last :-). Investigate what, if anything, that fragmentation has to do with the two Achilles heels of image-based development, namely me getting functionality that I want into my image and me removing functionality that I don't want from my image. - Peter

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Quit Squeak with code?
by Marcus Pedersén 03 Mar '06

03 Mar '06

Hi! If I want to quit Squeak , for example have a "Quit button", how do I do it with code instead of bringing worldmenu up? Many thanks! Marcus

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referencing objects (newbie)
by Eddie Hillenbrand 03 Mar '06

03 Mar '06

Hi everyone, I just downloaded Squeak two days ago, so far I love it. I want to use it to teach my little sister how to program. But first I need some help figuring out the basics. How do I refer to objects I create? If I create, for example, an EllipseMorph how can I refer to it in a Workspace, so I can send it messages using "do it"? I've figured out how to open a Viewer and change the object's name, but if I try to send it a message in a Workspace I get an "Unknown variable" error. Thanks, Eddie

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Grandfather of Smalltalk gets Turing Award [ACM Announces 2005 A.M. Turing Award Winner]
by Klaus D. Witzel 03 Mar '06

03 Mar '06

List, as you can see from the below, a grandfather of Smalltalk (Peter Naur: Algol, Backus-Naur-Form BNF) receives the 2005 Turing award. Q: anybody else besides Jecel and me who have used Algol ? :) /Klaus ------- Forwarded message ------- From: ACMBulletin <acmbulletin(a)ACM.ORG> To: acm-bulletin(a)ACM.ORG Cc: Subject: ACM Announces 2005 A.M. Turing Award Winner Date: Thu, 02 Mar 2006 17:26:48 +0100 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ACM Bulletin - March 2, 2006 Today's Topic: ACM Announces 2005 A.M. Turing Award Winner ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ACM has named Peter Naur the winner of the 2005 A.M. Turing Award, recognizing his pioneering work on defining the Algol 60 programming language. Algol 60 is the model for many later programming languages, including those that are indispensable software engineering tools today. The Turing Award, widely considered the "Nobel Prize of Computing," is named for British mathematician Alan M. Turing. First awarded in 1966, it carries a $100,000 prize, with financial support provided by Intel Corporation. Learn more about this year's A.M. Turing Award winner at: http://www.acm.org/2005_turing_award Dr. Naur was instrumental in establishing software engineering as a discipline. In 1960, Dr. Naur was editor of the hugely influential "Report on the Algorithmic Language Algol 60." He is recognized for the report's elegance, uniformity and coherence, and credited as an important contributor to the language's power and simplicity. The report made pioneering use of what later became known as Backus-Naur Form (BNF) to define the syntax of programs. BNF is now the standard way to define a computer language. Dr. Naur is also cited for his contribution to compiler design and to the art and practice of computer programming. ACM will present the Turing Award at the annual ACM Awards Banquet on May 20, 2006, in San Francisco, CA. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The ACM Bulletin Service provides ACM members with email notification of important association news and activities. Should you wish to be excluded from future issues of the acm-bulletin, please enter your email address klaus.witzel(a)COBSS.CH at http://www.acm.org/acm_bulletin and we'll remove you. Association for Computing Machinery Advancing Computing as a Science and Profession (c) 2006 ACM, Inc. All rights reserved.

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Re: About use of specific error
by Pascal Meunier 03 Mar '06

03 Mar '06

Hi Markus, > What is wrong with writing: > IntervalTest >> testRemove > self should: [(1 to: 3) remove: 2] raise: Exception There's nothing wrong with your test, but I prefer more specific errors. Why? probably because I prefer to run my tests automatically and then write a structured report. I work with VW, and when I search senders of methods like 'subclassRes*', I find senders of "subclassResponsability", "subClassResponsability", "subClassResponsibility" and so on. it's difficult to stay clean with selectors, and it's worst with strings. Once I had to check all the messages written in a server's log file. I had plenty of messages with the same meanning but with different sentences because each time a programmer had to log something (informations or errors), he wrote a specific string. I assume that when you have a Class hierarchy for errors, people tend to look at the hierarchy instead of creating their own errors, and as most of the time your kind of error is roughly the same as one already written. Regards, Pascal Markus Gaelli wrote: Hi Pascal, > It would be easier to catch and therefore to test with a specific > subclass of Exception. What is wrong with writing: IntervalTest >> testRemove self should: [(1 to: 3) remove: 2] raise: Exception > Besides, for the Interval>>remove: example, the code would have been: > > Interval>> remove: anElement > "elements cannot be removed from an Interval" > ^self shouldNotImplement So I need to browse the method and cannot see directly anymore what is going in the label of my walkback-window? > > Mind you, even in VW you have these calls of error:, and > shouldNotImplement is implemented that way... > But why not implementing shouldNotImplement like: > > Object>> shouldNotImplement > ^ShouldNotImplementError raise Why? Cheers, Markus --------------------------------- To help you stay safe and secure online, we've developed the all new Yahoo! Security Centre.

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Re: Squeak-dev Digest, Vol 39, Issue 4
by Pascal Meunier 03 Mar '06

03 Mar '06

Hi Markus, > What is wrong with writing: > IntervalTest >> testRemove > self should: [(1 to: 3) remove: 2] raise: Exception There's nothing wrong with your test, but I prefer more specific errors. Why? probably because I prefer to run my tests automatically and then write a structured report. I work with VW, and when I search senders of methods like 'subclassRes*', I find senders of "subclassResponsability", "subClassResponsability", "subClassResponsibility" and so on. it's difficult to stay clean with selectors, and it's worst with strings. Once I had to check all the messages written in a server's log file. I had plenty of messages with the same meanning but with different sentences because each time a programmer had to log something (informations or errors), he wrote a specific string. I assume that when you have a Class hierarchy for errors, people tend to look at the hierarchy instead of creating their own errors, and as most of the time your kind of error is roughly the same as one already written. Regards, Pascal Markus Gaelli wrote: Hi Pascal, > It would be easier to catch and therefore to test with a specific > subclass of Exception. What is wrong with writing: IntervalTest >> testRemove self should: [(1 to: 3) remove: 2] raise: Exception > Besides, for the Interval>>remove: example, the code would have been: > > Interval>> remove: anElement > "elements cannot be removed from an Interval" > ^self shouldNotImplement So I need to browse the method and cannot see directly anymore what is going in the label of my walkback-window? > > Mind you, even in VW you have these calls of error:, and > shouldNotImplement is implemented that way... > But why not implementing shouldNotImplement like: > > Object>> shouldNotImplement > ^ShouldNotImplementError raise Why? Cheers, Markus --------------------------------- Yahoo! Cars NEW - sell your car and browse thousands of new and used cars online search now ---------------------------------

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RE: About use of specific error
by Bany, Michel 03 Mar '06

03 Mar '06

> I'm teaching them to write tests and to write tests for a > class that raises exceptions you have to catch them and to > cover the potential behavior of the class! This is not my > wish or not to have exceptions, they are there and to cover > the method behavior (because of different programming > style) I have to cover them. > > For example, what happens if we access an element at not > existing index. Why not have your students write tests like this IntervalTest >> testRemove self should: [(1 to: 3) remove: 2] raise: Exception. [(1 to: 3) remove: 2] on: Exception do: [:ex | self assert: ex class == Error. self assert: ex description = 'elements cannot be removed from an Interval']. This clearly describes what is expected from the Interval class. Michel.

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