Squeak-dev September 1999

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133 participants
357 discussions

[BUG][FIX] ChangeSet class order
by Bob Arning 30 Sep '99

30 Sep '99

It is possible for the ChangeSorter to file out class definitions in an order that cannot be read back in. If you do the following Object subclass: #BBB instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'Kernel-Objects' followed by: BBB subclass: #AAA instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'Kernel-Objects' followed by: AAA class instanceVariableNames: 'some ' and then file out the current changeset, you get something like: 'From Squeak 2.5 of August 6, 1999 on 30 September 1999 at 2:39:31 pm'! AAA class instanceVariableNames: 'some '! Object subclass: #BBB instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'Kernel-Objects'! BBB subclass: #AAA instanceVariableNames: '' classVariableNames: '' poolDictionaries: '' category: 'Kernel-Objects'! and the compiler is not going to be happy with the first chunk. Attached is a fix. Cheers, Bob ==========fix below========== 'From Squeak 2.5 of August 6, 1999 on 30 September 1999 at 2:36:29 pm'! !ChangeSet class methodsFor: 'fileIn/Out' stamp: 'RAA 9/30/1999 14:34'! superclassOrder: classes "Arrange the classes in the collection, classes, in superclass order so the classes can be properly filed in." | all list i aClass | list _ classes copy. "list is indexable" all _ OrderedCollection new: list size. [list size > 0] whileTrue: [ i _ 0. [ i _ i + 1. aClass _ list at: i. (list includesAnyOf: aClass allSuperclasses) or: [ aClass isMeta and: [ (list includes: aClass soleInstance) or: [ list includesAnyOf: aClass soleInstance allSuperclasses ] ]. ]. ] whileTrue. all addLast: aClass. list _ list copyWithout: aClass ]. ^all! !

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Re: newbie silly question
by Leandro Caniglia 30 Sep '99

30 Sep '99

>> Now, in the workspace, I type: " >> AlignmentMorph new openInSpace >> " >> and print it. In this case, who shall I send the messages to? >In this case, you don't have a variable which you can send messages to >from within the workspace. >[a list of possibilities follows] .... or you can load the MorphicWrappers and "talk" to any object just writing your message "on the air". /Leandro

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Where Squeak is headed...
by Kevin Driedger 30 Sep '99

30 Sep '99

I just finished reading the comments on: http://www.squeak.org/headed.html and have found them to be inspirational. Perhaps it is time for an update... what do you say Dan? Here's To Squeak! ]{evin

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Re: Lobbying Smalltalk...
by Todd Blanchard 30 Sep '99

30 Sep '99

OK, this is my pet peeve so I'm going to whine. STOP THE MADNESS! This insane forced march of everything to Java for everything has got to stop. Apart from the fact that Java is a failure as a platform independent development tool and that its libraries are obviously quickly hacked and poorly thought out, its performance is generally slow slow slow. Java is just a craze. It will go away the way C++ did. Ignore the distraction. If you are looking for a sign - then I'd say that the day Java gets templates is the day it dies (although it will likely take a long time to fall over). > ...or: > Winning Ignorance > > Excuse me, > I'd like to talk about a small idea: creating a Squeak VM for Java > Using the CCodeGenerator engine, I think would be not so difficult to > generate a JavaCodeGenerator class for building java source code for the > VM. > We will have Squeak running in a JavaVM, perhaps a bit slowly. > After a bit of working, we can try to integrate the java GC, JavaBeans > and the Security concepts of Java into Squeak, generating a hybrid VM > and the Smalltalk of the future. > > A lot of java-students will look with interest to a Java-based > implementation of Smalltalk, and start to download the SqueakVM.... > > This is only an idea. I know the efficency problem 'd be not so tiny and > so I am only talking about it.... > ...someone interested? > > -- > // Giovanni Giorgi e-mail: giovanni.giorgi(a)mlab.disco.unimi.it > > // Master Thesis at http://mars.sal.disco.unimi.it/~giorgi > // Student & (ex)Tutor at Depart. of Computer Science of Milan, Italy. > > ------------------------------------------------------------------------- > > > > -- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ eTranslate, Inc. The Power of Language Todd Blanchard main +1.415.487.7850 Chief Technology Architect fax +1.415.371.0010 http://www.etranslate.com/ 520 Third Street, Suite 505, San Francisco, California 94107, U.S.A.

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3-D Modeling Programs
by Mark Guzdial 30 Sep '99

30 Sep '99

What are the 3-D Modeling Programs that can produce output that Balloon/Wonderland can read? I know that Balloon can read 3-D Studio format, but I don't know if those objects can be used in Wonderland. Wonderland can read VRML 2.0, OBJ (which I've learned is the Wavefront output format), and their internal MDL format. So, besides the Teddy application/applet and Wavefront, what software can produce objects that can be used in Wonderland? I've recently found some Mac 3-D modeling programs (e.g., http://www.strout.net/macsoft/meshwork/intro.html) but I don't know enough about 3-D modeling to tell if these are useful, e.g., can I somehow use 3DMF with Wonderland, or is there any easy way to convert 3DMF to OBJ? Thanks! Mark -------------------------- Mark Guzdial : Georgia Tech : College of Computing : Atlanta, GA 30332-0280 (404) 894-5618 : Fax (404) 894-0673 : guzdial(a)cc.gatech.edu http://www.cc.gatech.edu/gvu/people/Faculty/Mark.Guzdial.html

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Re: Lobbying Smalltalk...
by jecel＠lsi.usp.br 30 Sep '99

30 Sep '99

The JPython project that Andrew mentioned is certainly a better approach than tranlating the current VM to Java. Another effort of this kind is: http://www.ConsultAr.com/JSelf/ And there is a new home page for the Mushroom project that Peter mentioned, and it is certainly worth a look: http://www.sunlabs.com/~mario/mushroom/index.html -- Jecel

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Lobbying Smalltalk...
by Giovanni Giorgi 30 Sep '99

30 Sep '99

...or: Winning Ignorance Excuse me, I'd like to talk about a small idea: creating a Squeak VM for Java Using the CCodeGenerator engine, I think would be not so difficult to generate a JavaCodeGenerator class for building java source code for the VM. We will have Squeak running in a JavaVM, perhaps a bit slowly. After a bit of working, we can try to integrate the java GC, JavaBeans and the Security concepts of Java into Squeak, generating a hybrid VM and the Smalltalk of the future. A lot of java-students will look with interest to a Java-based implementation of Smalltalk, and start to download the SqueakVM.... This is only an idea. I know the efficency problem 'd be not so tiny and so I am only talking about it.... ...someone interested? -- // Giovanni Giorgi e-mail: giovanni.giorgi(a)mlab.disco.unimi.it // Master Thesis at http://mars.sal.disco.unimi.it/~giorgi // Student & (ex)Tutor at Depart. of Computer Science of Milan, Italy. -------------------------------------------------------------------------

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RE: [ENH] Empty return expression
by agree＠carltonfields.com 30 Sep '99

30 Sep '99

Please forgive my ignorance, without saying they are absent, I do not see the virtues of this "implicit return" earlier in the method. The argument as put here "feels" to me much like those made by the pro-Goto camp (this is not intended as pejorative) during the debates of the 70's in imperative languages. Do these really make things clearer in any meaningful way? > -----Original Message----- > From: MIME :dway@mat.net > Sent: Monday, September 27, 1999 12:09 PM > To: squeak(a)cs.uiuc.edu > Subject: RE: [ENH] Empty return expression > > > > On Mon, 27 Sep 1999, Jarvis, Robert P. wrote: > > > I don't like this because IMO it obfuscates what's going on > without adding > > value. > > On the contrary, I'd say it's more clear as to the intention of the > return, which does add value. > > Basically, it says that you want to exit the method at a > certain point, > and that there is no return value to be used. > > It's the equivalent of an implicit return, except earlier in > the method. > Kent Beck and others recommend using implicit returns when > the method is > not intending to return anything, because it makes the intention more > clear (and I agree). (In other words, with an implicit return, the > calling method should not use the returned value.) > > So, this seems like a good equivalent of an implicit return, > except that > it is done earlier in the method, because you need to break out of the > method. Returning "^self" is misleading, because it implies that you > might want to specifically return "self" to be used by the > caller. (True, > most Smalltalkers recognize "^self" as a generic return, but it's not > always that way.) > > I have to admit I thought it looked a little funny for a > minute, but it > seems like a good idea. (unless there's some other potential > problem I'm > missing) > > - Doug Way > EAI/Transom Technologies, Ann Arbor, MI > http://www.transom.com > dway(a)mat.net, @eai.com > > > > > If you want to answer self in this situation, then type > > > ^self > > > This requires four keystrokes, and it's clear. Besides, > if the method is > > going to answer 'nothing returned' shouldn't it answer nil > instead of self? > > > Bob Jarvis > > The Timken Company > > > > -----Original Message----- > > > From: Bert Freudenberg [SMTP:bert@isgnw.CS.Uni-Magdeburg.De] > > > Sent: Monday, September 27, 1999 4:36 AM > > > To: squeak(a)cs.uiuc.edu > > > Subject: [ENH] Empty return expression > > > > > Parser patch to allow empty returns that indicate > 'nothing returned' like > > foo ifTrue: [self doSomething. ^] > > > instead of the currently often (mis-)used > > > foo ifTrue: [^self doSomething] > > > as short form of > > > foo ifTrue: [self doSomething. ^self] > > > > > Discussion: > > This syntax matches the implicit > return of self at the end of > > > a method. It makes the "void" return type of a method > explicit, which is > > > good for self-documenting code. It's backwards > compatible. It's a minor > > > change in the parser. So why not? > > > > > It's not compatible to other Smalltalks - but then, > the brace constructs > > > are even more different. > > > > > /bert << File: >> > > > > > >

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Re: An image is a lonely place
by John Tobler 30 Sep '99

30 Sep '99

I think it was Edward P Luwish who wrote: > An admiring comment: > > The extent to which people are developing and > proposing visionary solutions in Smalltalk is > mind-boggling. No other software invention in > my memory has inspired such a flood of > innovations. .... This may be a bit unfair to some other very dynamic OpenSource initiatives. In particular, the Python community has proven itself *most* fertile. They are doing some really cool stuff (TM). That said, I certainly share your gushing admiration for those who have given us Squeak! Thanks and kowtows to our mutual heroes (Hmmmm. Are there, perhaps, heroines to be thanked as well?) Blessings to all! /John _______________________________________________________ Get Visto! Groups, event calendars, email, and more... Check it out @ http://www.visto.com/info

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A warning on HandMorph|handleMouseOver:
by Leandro Caniglia 30 Sep '99

30 Sep '99

The current implementation of HandMorph|handleMouseOver: is risky in that, in some circumstances, it can blow up a common mistake and produce a pollution of walkback windows that are hard to close. The side effect is due to the use of the mouseOverTimes dictionary. The keys of this dictionary are morphs and the values are integers representing times in milliseconds. When the keys of the dictionary are enumerated in the fragment: 1 mouseOverTimes keys do: 2 [:m | "Check pending timers for lingering" 3 t _ mouseOverTimes at: m. 4 "and so on" the code is assuming that m has a well defined hash. If that precondition fails, then the morph m is in the set of keys but the invocation of at: m produces a keyNotFound error. And of course, the error repeats again and again. IMO this behavior is opposite to the stability of the system for one simple reason: the programmer who creates a Morph subclass must be aware of the fact that each morph is going to be included in a Dictionary and thus she must provide an infallible hash method. Moreover, the pollution of walkbacks is not in proportion with the offending mistake which is hard to debug and figure out. Think that most of the times, the initialize method for a new morph has a temporary effect: once the morph has been created, it is re-initialized to its full state. Thus a #hash that is correct and stable from a logical point of view, can change in the interim between steps 1 and 3 (see the fragment above). Since Morphic is a laboratory, we should keep it safe from the accidents produced during experimentation. Specially when this laboratory is being visited by non-experienced users. A partial solution to this problem is to rehash the dictionary if it fails to access the morph: 1. mouseOverTimes keys do: 2. [:m | "Check pending timers for lingering" 3. t _ mouseOverTimes at: m ifAbsent: [mouseOverTimes rehash at: m]. 4. "and so on" This solution is partial in that it does not handle all possible defective hashes. But I think it is safe enough. In any case, my intention is not to provide the best solution but to rise a warning about this situation. /Leandro PS: I'm sending this mail to Scott since he is the author who last signed the method in 2.5. PPS: One more time, the MorphicWrappers made this problem apparent.

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