Squeak-dev November 2008

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119 participants
135 discussions

Re: Problem with bullets in swiki
by Jerome Peace 29 Nov '08

29 Nov '08

[squeak-dev] Problem with bullets in swiki Hi Mariano, What a merry chase. I looked at the wiki. It was pairing up *'s the line: - some libopendbx*(10) in /usr/local/lib had an unmatched '*' which was matching with the last one at the end of your numbered list. While looking for the match the wiki was not in the mood to handle the list in the normal way. I removed that and everything worked fine. I also remove the white space infront of the - above to get the wiki to format those three lines with bullets. I edited the page to find the problem. For more info you can look at the page history. Yours in curiosity and service, --Jerome Peace *** >Mariano Martinez Peck marianopeck at gmail.com >Fri Nov 28 22:53:53 UTC 2008 > > >Hi list! I think I found a bug in swiki. Can you look to this URL please? >http://wiki.squeak.org/squeak/6061 > >If you see above, there are 3 bullets (from 1 to 3). Each of these 3 >elements is at one line. Each down the other. > >If you see below, there are 8 bullets. But there are some problems: > >- No matter how I write it in the wiki, they are listed in the same line >- It doesn't show the number of the bullet > >Can someone help me? I would like to have these 8 bullets like the 3 that >are above. > >Thanks for the help, > >Mariano ***

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How do I install Squeak on Fedora? Aspire One netbook
by hh2＠lexdb.net 29 Nov '08

29 Nov '08

Hello I would like to install Squeak on Fedora, in particular on an Aspire One netbook, which uses Linpus which is based on Fedora. http://distrowatch.com/table.php?distribution=linpus The process does not seem to be as straightforward as in Ubuntu: There you can at install version 3.9 version with the 'Add/Remove software' menu which is the last entry in the main menu. DOCUMENTATION TRAIL LEEDS TO A DEAD END http://www.squeak.org/Documentation/Installation refers to the wiki, http://wiki.squeak.org/squeak/3616 but this page is only about debian. That page though has on top a link to a more general page called 'Download for Unix' http://wiki.squeak.org/squeak/298 Which in fact then leads to http://squeakvm.org/unix/ http://squeakvm.org/unix/download.html PROBLEM: NO RPM FILE AVAILABLE There is no RPM file for a VM for Squeak 3.10 or Squeak 3.9. found through the links in the previous paragraph. I am pretty sure that somebody as worked on this and that there is a Fedora RPM package available with everything in it for Squeak 3.9 and Squeak 3.10. Or at least a VM. However the links have not been updated, if you start exploring from www.squeak.org. I am willing to update the wiki with the upcoming answers. So thank you for your answers in advance. Hannes Hirzel P.S. DETAILS ABOUT SOFTWARE INSTALLATION ON THE ASPIRE ONE NETBOOK The Aspire One as such does not have an 'add software' menu entry as it comes right out of the box. But it can easily be activated as follows: Under 'Myfiles' from the front launchpad you get access to the xfce file manager called 'Thunar'. In the file menu there it is possible to get a terminal and then to use xfce-setting-show A dialog box pops up. Then choose the 'desktop' icon, the 'behaviour' tab and click on the 'show desktop menu on right click' checkbox. Then from the desktop menu you get access to the 'System' menu which includes 'add/remove software' to start the RPM package manager. However I feel comfortable as well to install from the command line as long as I do have to type only a few lines and can rely on good instructions what these lines are. The particular Aspire One model I use to write this mail comes with 1GB of memory and a 120GB hard disk at an attractive price. It might be used as a server in an small intranet. In fact s simpler netbook would still do the job for running Squeak comfortably.... -------------------------------------------------------------------- myhosting.com - Premium Microsoft® Windows® and Linux web and application hosting - http://link.myhosting.com/myhosting

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#07212 flaps render *properly* during StandardSystemFontsTest
by Mr. Timothy C. Johnson 29 Nov '08

29 Nov '08

Hi, It is known that flaps render improperly in 3.10.x -- there is a ~1 pixel dead zone on some of the flaps. But I just ran System-Support-Tests>>StandardSystemFontsTest and something it did made the flaps render properly, all of a sudden. Any idea why? - timj

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Problem with bullets in swiki
by Mariano Martinez Peck 28 Nov '08

28 Nov '08

Hi list! I think I found a bug in swiki. Can you look to this URL please? http://wiki.squeak.org/squeak/6061 If you see above, there are 3 bullets (from 1 to 3). Each of these 3 elements is at one line. Each down the other. If you see below, there are 8 bullets. But there are some problems: - No matter how I write it in the wiki, they are listed in the same line - It doesn't show the number of the bullet Can someone help me? I would like to have these 8 bullets like the 3 that are above. Thanks for the help, Mariano

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Fwd: [squeak-dev] Graduation position (Smalltalk involved), Amsterdam, the Netherlands.
by Mathieu van Echtelt 28 Nov '08

28 Nov '08

Hi Edgar, No we did not loose faith. We think it is good to separate execution/deployment mode from development mode. (isn't this the same reason why we have virtual machines in the first place?). In execution mode you have different requirements (e.g. scalability, speed, supporting hosting providers) compared to being in development mode (e.g. live debugging, instant feedback, reflection). This graduation project is not about going away from Smalltalk or going to java, python or whatever other technology with an identifying name. It is about investigating separation, and we believe it is a good approach to pick an execution platform which is especially not-smalltalk to help us prove/investigate if our "business descriptions" are indeed as implementation independent as we hope they are. Of one thing we are sure though: In many many many ways Smalltalk is absolutely superior (even after all those years it is around!) but is not the end, nor is Python, nor is Java. greetings, Mathieu van Echtelt On Fri, Nov 28, 2008 at 3:02 PM, Edgar J. De Cleene <edgardec2001(a)yahoo.com.ar> wrote: > > On 28/11/2008, at 09:54, Mathieu van Echtelt wrote: > > A student could research if and how our current business domain model > > descriptions can be executed on an alternative execution platform > > (e.g. Java, Python). This research might conclude other platforms are > > not easily supported, because certain constructions in our current > > descriptions are to Smalltalk specific. In such a case, it should be > > made clear what the consequences are to remove the Smalltalk > > dependencies from our current business domain descriptions. > > So you lost faith. > Believing Java or Python solves some and Smalltalk not put you almost out of > Our Magic Kingdom :=) > I not saying you can't got more money with your choice... > Edgar > > > -- AG5 - Product manager -- AG5 - Product manager

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Graduation position (Smalltalk involved), Amsterdam, the Netherlands.
by Mathieu van Echtelt 28 Nov '08

28 Nov '08

Hi all, We've a graduation position for the following project: -- Title: "Domain descriptions & execution platforms" 1) Problem Current dependencies between business domain descriptions and execution platform make our software product less flexible in using alternative execution platforms. 2) Research question How to increase flexibility in using alternative execution platforms for our business domain descriptions? 3) Research goal Research if and how our current business domain descriptions can be executed on an alternative execution platform (e.g. Java, Python). 4) Context In our system the business domain is described in a high level of abstraction. The general idea is to enable our "business modelers" to describe their knowledge about the business domain within this high level of abstraction. They do not have to worry about all kinds of implementation aspects such as persistency, user interface technologies, classes, variables, referential integrity, etc, because the code for these technical aspects is automatically generated from the business domain descriptions. The business domain descriptions, the code generators as well as most part of the generated code is expressed in the programming language Smalltalk (VisualWorks). Even though we're very happy with our approach and with Smalltalk, we realize there are possibilities for a stricter boundary between business domain descriptions and execution platform. This will give us more flexibility in choosing different (potentially more interesting) deployment strategies. A student could research if and how our current business domain model descriptions can be executed on an alternative execution platform (e.g. Java, Python). This research might conclude other platforms are not easily supported, because certain constructions in our current descriptions are to Smalltalk specific. In such a case, it should be made clear what the consequences are to remove the Smalltalk dependencies from our current business domain descriptions. 5) About AG5 We are a small company (6 people, of which 5 developers). We believe our in-house base-technology R&D and our use of a dynamic and reflective development language (Smalltalk) help us being very successful in a competitive market. Since our start in the December 2005, we are focused on development and sales of one product: a people's skills & schedule management system for fire-, health care-, safety departments. More than 100 governmental institutions work daily with our web-based system. One of our developers is a former computer science teacher with experience in assisting students for their graduation. When you are interested in doing your research or work within our company, let us know! Send your email with motivation to mathieu at ag5 . nl. Greetings, Mathieu van Echtelt www.ag5.nl Amsterdam, the Netherlands

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Re: Instance variable access in superclasses.
by Ralph Boland 28 Nov '08

28 Nov '08

My idea here is too late for squeak but is food for thought for the next great object oriented programming language. Instead of using a full fledged message send for accessing instance variables we could use a compromise. Lets say that symbol @ is special and cannot be used as a regular message and let var be an instance variable of a class MyClass and used in MyClass method myMethod. Then to access var in myMethod we can write: @ var. as in: ^ @ var or even: @ var := 5. With this notation local variables and instance variable are distinguishable which results in safer and (arguably) more readable code. One way of implementing this would be to require that MyClass define instance variable var or an error message would be generated. The other way of doing this would be to not require that MyClass define var. However, if var is not defined, then myMethod would be abstract and unusable by MyClass. Instead only subclasses of MyClass that define instance variable var could use the myMethod. This would mean that versions of myMethod would need to be compiled for each subclass that defined var. If the additional byte code generated was considered too wasteful then one could always use regular message sends. I would strongly recommend that abstract variables (such as var) and abstract methods somehow be clearly marked. I would also recommend that, when var is defined in a subclass, symbol @ be placed in front of it to flag that an abstract variable is being made concrete as opposed to a brand new instance variable being created. (calm) opinions welcome. Ralph Boland

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Files documentation
by Mariano Martinez Peck 28 Nov '08

28 Nov '08

Hi list! I need to do some things with files (text and binaries), and I would need information about creating, deleting, adding, appending, writting and so on with them. I look in SBE but I didn't find a chapter about that. Is somewhere documentation about this? thanks, Mariano

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Re: Instance variable access in superclasses.
by nicolas cellier 27 Nov '08

27 Nov '08

Jecel Assumpcao Jr a écrit : > nicolas cellier wrote: >> James Foster a écrit : >>> On Nov 25, 2008, at 7:45 PM, Igor Stasenko wrote: >>>> My understanding of inheritance is different, in short: >>>> A subclass of particular class is a _specialization_ of base class, >>>> not _expansion_. >>> In this context, I sometimes wonder if Square should inherit from >>> Rectangle (a specialization in which width and height are equal), or >>> Rectangle should inherit from Square (adding an instance variable). Am I >>> right that you would have Square inherits from Rectangle (Square being >>> more specialized)? But then it feels like we are wasting an instance >>> variable (since Rectangle would have two). >> Beware, you're dangerously sliping to multiple inheritance because your >> Square might also be a lozenge :) > > With the Rectangle as subclass of Square option this wouldn't be a > problem - you would just have two different subclasses of Square. > > Could Rectangle be a subclass of Square? Sure: > > - Square instance variables: center, size, orientation > > - Rectangle adds this instance variable: aspectRatio > Following proposition does not seem to match what we learned at school (Rectangle isKindOf: Square) -> true But with a different POV, yes, a Rectangle isKindOf (degenerated) Square, a flatten one. So why not. However, the question, apart inst vars is what methods/algorithm should/could be inherited. It seems to me that Square being a Rectangle could safely inherit all Rectangle methods. The reverse is not necessarily true, and this scheme would force to re-examine method by method which one to override because Square assumption is not true anymore (think of a method exploiting orthogonal diagonals properties for example). That is somehow fragile. Each time you add a method to Square, you must think in term of Rectangle or Lozenge... That breaks some kind of encapsulation no? > We can make Ellipse a subclass of Circle using the same style. We can > even have an #aspectRatio method in Square and Circle which always > returns 1 and then we can move some of the more general code up in the > classes hierarchy if we want to. > > For raster graphics it is convenient to define Rectangles as always > parallel to the screen axis so that just two points are enough to fully > identify them. Perhaps calling them RasterRects instead would have made > us think more clearly about them. We later moved to vector graphics > (Balloon) but were stuck with the historic baggage. > > -- Jecel > P.S.: I am aware that even in this scheme you might want Parallelogram > to inherit from both Rectangle and Lozenge (actually, Rhombus is more > generic) and then you have the multiple inheritance problem again. Which > is what Traits are for... > > > Of course. Nicolas

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Q: Value of just the period, in method body resp. block body
by Klaus D. Witzel 27 Nov '08

27 Nov '08

Quick, what does this method return: MyClass>>myMethod. and what does this method's block return: MyClass>>myBlock ^[.]value I'm writing compiler tests for CorruptVM/Moebius (tests that can then also be used with Squeak's compiler and NewCompiler) and want to include these two cases as well. TIA. /Klaus -- "If at first, the idea is not absurd, then there is no hope for it". Albert Einstein

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