Squeak-dev July 2007

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140 participants
214 discussions

Error after installing from Universes
by Giuseppe Luigi Punzi Ruiz 30 Jul '07

30 Jul '07

Hi list, I opened the last squeak-dev image and after updating the packages from the net, select upgrades, and install selected. Now, If I open a Preferences Browser, I get DNU. I don't know if this was reported, Some weeks without read the list. This is the log. Error: MessageNotUnderstood: UndefinedObject>>pixelValueForDepth: 22 July 2007 1:03:15 am VM: Mac OS - a SmalltalkImage Image: Squeak3.9 [latest update: #7067] SecurityManager state: Restricted: false FileAccess: true SocketAccess: true Working Dir /Users/glpunzi/Desarrollo/estable Trusted Dir /foobar/tooBar/forSqueak/bogus Untrusted Dir /Users/glpunzi/Library/Preferences/Squeak/Internet/My Squeak UndefinedObject(Object)>>error: Receiver: nil Arguments and temporary variables: aString: 'MessageNotUnderstood: UndefinedObject>>pixelValueForDepth:' Receiver's instance variables: nil [] in WorldState>>displayWorldSafely: {[:err :rcvr | errCtx := thisContext. [errCtx := errCtx sender. [errCtx no...]} Arguments and temporary variables: aWorld: a PasteUpMorph(1622) [world] err: 'MessageNotUnderstood: UndefinedObject>>pixelValueForDepth:' rcvr: nil errCtx: LazyListMorph>>display:atRow:on: errMorph: a LazyListMorph(3977) BlockContext>>valueWithPossibleArgs: Receiver: [] in WorldState>>displayWorldSafely: {[:err :rcvr | errCtx := thisContext. [errCtx := e...etc... Arguments and temporary variables: anArray: #('MessageNotUnderstood: UndefinedObject>>pixelValueForDepth:' nil) Receiver's instance variables: sender: BlockContext>>valueWithPossibleArgs: pc: 121 stackp: 0 nargs: 2 startpc: 74 home: WorldState>>displayWorldSafely: [] in BlockContext>>ifError: {[:ex | errorHandlerBlock valueWithPossibleArgs: {ex description. ex receiver}]} Arguments and temporary variables: errorHandlerBlock: [] in WorldState>>displayWorldSafely: {[:err :rcvr | errCtx...etc... ex: MessageNotUnderstood: UndefinedObject>>pixelValueForDepth: --- The full stack --- UndefinedObject(Object)>>error: [] in WorldState>>displayWorldSafely: {[:err :rcvr | errCtx := thisContext. [errCtx := errCtx sender. [errCtx no...]} BlockContext>>valueWithPossibleArgs: [] in BlockContext>>ifError: {[:ex | errorHandlerBlock valueWithPossibleArgs: {ex description. ex receiver}]} - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - BlockContext>>valueWithPossibleArgs: [] in MethodContext(ContextPart)>>handleSignal: {[(self tempAt: 2) valueWithPossibleArgs: {exception}]} BlockContext>>ensure: MethodContext(ContextPart)>>handleSignal: MessageNotUnderstood(Exception)>>signal UndefinedObject(Object)>>doesNotUnderstand: #pixelValueForDepth: DisplayScreen(Form)>>pixelValueFor: GrafPort(BitBlt)>>installStrikeFont:foregroundColor:backgroundColor: GrafPort>>installStrikeFont:foregroundColor:backgroundColor: StrikeFontSet>>installOn:foregroundColor:backgroundColor: FormCanvas>>drawString:from:to:in:font:color: FormCanvas(Canvas)>>drawString:in:font:color: LazyListMorph>>display:atRow:on: LazyListMorph>>drawOn: FormCanvas(Canvas)>>draw: FormCanvas(Canvas)>>drawMorph: [] in LazyListMorph(Morph)>>fullDrawOn: {[(aCanvas isVisible: self bounds) ifTrue: [aCanvas drawMorph: self]. self...]} FormCanvas>>roundCornersOf:in:during: FormCanvas(Canvas)>>roundCornersOf:during: LazyListMorph(Morph)>>fullDrawOn: FormCanvas(Canvas)>>fullDraw: FormCanvas(Canvas)>>fullDrawMorph: [] in TransformMorph>>drawSubmorphsOn: {[:m | myCanvas fullDrawMorph: m]} Array(SequenceableCollection)>>reverseDo: [] in TransformMorph>>drawSubmorphsOn: {[:myCanvas | submorphs reverseDo: [:m | myCanvas fullDrawMorph: m]]} FormCanvas>>transformBy:clippingTo:during:smoothing: TransformMorph>>drawSubmorphsOn: [] in TransformMorph(Morph)>>fullDrawOn: {[(aCanvas isVisible: self bounds) ifTrue: [aCanvas drawMorph: self]. self...]} FormCanvas>>roundCornersOf:in:during: FormCanvas(Canvas)>>roundCornersOf:during: TransformMorph(Morph)>>fullDrawOn: FormCanvas(Canvas)>>fullDraw: FormCanvas(Canvas)>>fullDrawMorph: [] in PluggableListMorph(Morph)>>drawSubmorphsOn: {[:m | canvas fullDrawMorph: m]} Array(SequenceableCollection)>>reverseDo: [] in PluggableListMorph(Morph)>>drawSubmorphsOn: {[:canvas | submorphs reverseDo: [:m | canvas fullDrawMorph: m]]} PluggableListMorph(Morph)>>drawSubmorphsOn: [] in PluggableListMorph(Morph)>>fullDrawOn: {[(aCanvas isVisible: self bounds) ifTrue: [aCanvas drawMorph: self]. self...]} FormCanvas>>roundCornersOf:in:during: FormCanvas(Canvas)>>roundCornersOf:during: PluggableListMorph(Morph)>>fullDrawOn: FormCanvas(Canvas)>>fullDraw: FormCanvas(Canvas)>>fullDrawMorph: [] in Morph>>drawSubmorphsOn: {[:m | canvas fullDrawMorph: m]} ...etc... Cheers.

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Syntax Error while installing Squeak-Dev image from package universe
by Andreas Wacknitz 29 Jul '07

29 Jul '07

When I try to install the Squeak-Dev image version 0.126 in a fresh squeak3.10beta-7130 image I get a Syntax Error in Installer>>mcInstall: Installer version is 1.0.122. Is this a known problem? Regards Andreas

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Message monitor tool
by Joseph Blatter 29 Jul '07

29 Jul '07

Is there a tool for monitoring message sending in real time? I just want to trace all the messages an instance receive, but I don't care any kind of profiling like MessageTally. Cheers --------------------------------- Ne gardez plus qu'une seule adresse mail ! Copiez vos mails vers Yahoo! Mail

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[ANN] WideString findSubstring patch attempt
by nicolas cellier 28 Jul '07

28 Jul '07

I put some workaround at http://bugs.squeak.org/view.php?id=6366 Maybe tests can be completed, but that's a start. Any volunteer to cross check ? This also makes the test from Philippe give these results: '#:\*' match: (String with: (Unicode value: 50976) with: (Unicode value: 47532) with: (Unicode value: 47484)). -> false '*' match: (String with: (Unicode value: 50976) with: (Unicode value: 47532) with: (Unicode value: 47484)). -> true Beware: (Character value: 47484) and (Unicode value: 47484) are not the same because of the charSet encoded in leadingChar... In curent multilingual implementation, (Character value: 47484) is not really usable... Nicolas

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RE: Message Eating Null - article
by J J 28 Jul '07

28 Jul '07

I am not decided against the generalized null pattern just yet [1]. I just wanted to point out that no one is going to put 5 temps in a row like that. The exception might be more common but I never see it.[1] I am not going to say it's bad, nor am I convinced it is a sure win. Personally I can't recall a single time I have needed something like this. I do tend to chain messages often, but I guess I only do that when I don't expect a nil. If one comes up I want to see it right then to track it down. But perhaps in other domains then I have been programming in so far it would come up more. At any rate I'm glad it's out there to try out if I need it. Thanks for that Keith.> From: water(a)tunes.org> Date: Thu, 26 Jul 2007 12:41:05 -0700> To: squeak-dev(a)lists.squeakfoundation.org> Subject: Re: Message Eating Null - article> > Hello,> > I would like to point out that both of these claims are unrealistic.> > Specifically, Keith's examples all use low-level control-flow > messages like "notNil ifTrue: [" whereas non-novice Smalltalkers > should be using "ifNotNil:" and "ifNotNilDo: [:obj |".> > The example would best be:> > widget setStringValue: (#(office phone lastNumberDialed asString) > inject: person into: [:obj :sel | obj ifNotNil: [obj perform: sel]])> > without the message-eating Null pattern. Or if #perform: irks you, > you can use:> > widget setStringValue: (person office ifNotNilDo: [:office | office > phone ifNotNilDo: [:phone | phone lastNumberDialed ifNotNilDo: > [:number | number asString]]])> > Like Keith, I find this a problem to have to write and maintain in > code, but I'm not compelled to write long essays on it. I tend to > think that chained message-sends represent a way in which distantly- > related code can reach across protocols a bit too far. And Keith is > being a bit unfair in that a several-page-long essay (with a really > wide column justification width) will not be adequately rebutted in > an email forum, thus keeping the discussion from balance.> > My own view is that message-eating null is usable in controlled > circumstances, but that in general one cannot control the > circumstances (you can't know who *won't* receive a null as a > parameter, so code written without that in mind fails in strange > ways) in Smalltalk-80.> > It is also worth pointing out that "message-eating null" most closely > resembles the apposition of type T to NIL in Lisp, where one is the > supertype of every type and the other is the subtype of every type. > In Lisp, you do not interchange these, for good reason that I believe > applies here but don't have time to gather evidence in support.> > I think his packages which use message-eating-null would be a lot > more palatable if they didn't...> > On Jul 26, 2007, at 12:06 PM, Keith Hodges wrote:> > >> Yuck, I wouldn't do either of those. I would do:> >>> >> widget setStringValue: #(office phone lastNumberDialed asString) > >> inject: person into: [:obj :sel| o == nil ifTrue: [ nil ] ifFalse: > >> [ obj sel ] ]> > you would?> >> > To me the above looks as close to perl as smalltalk is hopefully > > ever likely to get!> >> > ;-)> > That is disingenuous. Please use honest arguments.> > > Keith> >> > p.s. Someone once accused me of being a PL/1 programmer in a former > > life.> > --> -Brian> http://briantrice.com> > _________________________________________________________________ Local listings, incredible imagery, and driving directions - all in one place! Find it! http://maps.live.com/?wip=69&FORM=MGAC01

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RE: Message Eating Null - article
by J J 28 Jul '07

28 Jul '07

> Date: Sat, 28 Jul 2007 09:43:15 +0200> From: cdegroot(a)gmail.com> To: squeak-dev(a)lists.squeakfoundation.org> Subject: Re: Message Eating Null - article> > I think it *is* an honest argument. One of the strong points of> Smalltalk is its readability, and that code block was awful in that> respect.The block itself, or you mean the #inject:into:? If you just mean the block, then I must say that's quite a reaction! I would certainly have switched to #ifNotNil: or something before committing it to a repository but it wasn't *that* bad.If you mean the #inject:into: then I disagree. To me the truly interesting thing about Smalltalk is it's beautiful mix of OO and functional programming. I don't go around throwing #inject:into: into everything I see, but in this case the example was an obvious traversal that would either require creating a new class (as he did) or using a general operator to short-circuit a call chain if a nil shows up (since nil was an acceptable value). In my personal opinion the #inject:into: would be more readable unless you specifically point out that a NullObject pattern is being used. But certainly wouldn't want some preference somewhere that says "switch my image to null pattern".Writing unreadable code does not mean using advanced features of the language/libraries to simplify something. I would certainly choose the #inject:into over that mess with temp variables all over. We shouldn't fear to use the power of our language. _________________________________________________________________ Local listings, incredible imagery, and driving directions - all in one place! Find it! http://maps.live.com/?wip=69&FORM=MGAC01

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RE: Message Eating Null - article
by J J 28 Jul '07

28 Jul '07

> Date: Thu, 26 Jul 2007 13:14:52 -0700> From: tapplek(a)gmail.com> To: squeak-dev(a)lists.squeakfoundation.org> Subject: Re: Message Eating Null - article> > > What on earth are you talking about????? That is #inject:into:, known in> > functional programming as a fold. > > I agree; that is a seriously obfuscated way to access the last> number dialed. I don't know how often 4-level chaining would> arise in practice, but I would hope it would be as simple as:> > ^ self office phone lastNumberDialed asString> > Anything more complex is not lazy enough to get diligently> applied everywhere it shouldYes, but it isn't quite that simple. Normally I would do exactly what you suggested. But in that case I would want a debugger if any of those messages returned nil. If you want different handling for nil then the default you have to do a test after each message send. This can either be done by making a special object as Keith suggested, using a fold as I suggested or brute forcing your way through as in Keith's example of what not to do. :) _________________________________________________________________ Don't get caught with egg on your face. Play Chicktionary! http://club.live.com/chicktionary.aspx?icid=chick_wlmailtextlink

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inject into (was RE: Message Eating Null - article)
by J J 28 Jul '07

28 Jul '07

Ah, I see. Well not being able to read code because it uses concepts that are currently alien to you is quite different then not being able to read code because it looks like cursing cartoon characters. :)There are basically 3 things you can do do a list of entities: (1) you can *transform* it to some other kind of list (i.e. #collect in Smalltalk, map in most functional languages), (2) you can *filter* it (i.e. #select/#reject in Smalltalk, filter in most functional languages) and (3) you can *reduce* it (i.e. #inject:into: in Smalltalk, foldl/foldr in most functional languages).The interesting thing about the reduction is that all other traversals can be expressed with it. But, as you mentioned, reduction is the hardest of the others to understand at first.For me the easiest way to understand it is if you imagine a list #(1 2 3 4 5) can also be expressed as 1 : 2 : 3 : 4 : 5 : [], where : means cons the left hand side value onto the front of the list on the right hand side. So 5 : [] is the same as #(5). The list is built from right to left so the above two lists are equivalent.Now, what a fold does is it replaces every : with a function and the [] with the value you supply. So if we wanted to sum the above numbers we can say: #(1 2 3 4 5) inject: 0 into: [:a :b | a + b]. This changes the list 1 : 2 : 3 : 4 : 5 : [] into 1 + 2 + 3 + 4 + 5 + 0.Now, what I said is true for foldl and foldr (the difference between those two functions is just which side do you start adding them up, going left or going right), but #inject:into (a right fold) has the difference that it injects the value into the *front* instead of the end. But this is probably what you want most cases for an OO language where the inserted value is likely the object you want the list to reduce on.> Date: Thu, 26 Jul 2007 20:54:20 +0100> From: keith_hodges(a)yahoo.co.uk> To: squeak-dev(a)lists.squeakfoundation.org> Subject: Re: Message Eating Null - article> > > >> > > > widget setStringValue: #(office phone lastNumberDialed asString)> > > > inject: person into: [:obj :sel| o == nil ifTrue: [ nil ] ifFalse: [> > > > obj sel ] ]> > >> > Not being that clever, I find #inject:into: to be the most obfuscated > message in the image. Whenever I see it I have to think quite hard to > work out what is going on.> > I was confused long before I got to the block.> > The original code has the advantage that it works without me needing to > know how exactly the effect is achieved.> > cheers> > Keith> _________________________________________________________________ See what you’re getting into…before you go there. http://newlivehotmail.com

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Possible patch for Semaphore>>critical
by Damien Cassou 28 Jul '07

28 Jul '07

2007/7/28, Andreas Raab <andreas.raab(a)gmx.de>: > Ah yes, of course. You're missing another batch of fixes that we have > long applied to our servers. In this case it's the handling of > Semaphore>>critical: (which is broken in all Squeak versions). Give the > attached changes a try and if it still don't work I'm sure there are > more fixes that we've applied in the meantime ;-) Can Andreas' patch be integrated into 3.10? -- Damien Cassou

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How to display my name on the author column when uploading a package
by An-Hoe Shih 28 Jul '07

28 Jul '07

Hi, I am a novice to Squeak and to SqueakSource. I tried to use Monticello to update a couple of packages and I noticed that for the packages that I've uploaded to squeaksource.com, the author column is blank. How do I fill in my name? Thanks, An-Hoe ____________________________________________________________________________________ Yahoo! oneSearch: Finally, mobile search that gives answers, not web links. http://mobile.yahoo.com/mobileweb/onesearch?refer=1ONXIC

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