Squeak-dev October 2012

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Squeak Community Meeting now
by Chris Cunnington 14 Oct '12

14 Oct '12

https://plus.google.com/u/0/events/c0nfhlfod6ogn3aumsq6seda7g8?cfem=1 Chris

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Question about class and instance
by Joseph J Alotta 13 Oct '12

13 Oct '12

Is there a general rule for class and instance? For example, if there should be only one instance of an object, should it be a class object? Or if I expect it to stay in memory and be available all the time, should it be a class object? Thank you.

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Traits as a way of defining an interface instead of an abstract superclass
by Chris Cunnington 13 Oct '12

13 Oct '12

I've been looking at MetaObjects's [1] decade old implementation of the vm in Cocoa. It has a class called SqueakInterpreter.h that defines a protocol that is used in SqView. The selectors are listed in SqueakInterpreter.h but implemented in SqView.m. I believe this kind of thing is now called a category in Objective-C-ese. And I was wondering why somebody would do this? We don't separate the protocols from the classes in Smalltalk. And I think the reason is we use abstract superclasses. And we have deep user developed hierarchies. Then it occurred to me that Objective-C doesn't have any user hierarchies of any depth. There are framework hierarchies of great depth. But the programmer in Objective-C from the start is supposed to go straight to composition and only produce very shallow hierarchies. I've got a book where a designer of Objective-C says inheritance is superfluous.[2] OK. Composition good. Inheritance bad. And it explains why there is no decent hierarchy browser in Xcode 4. There was one in Xcode 3 and they tossed it. And following these protocols from where they are defined to where they are implemented and where all developer hierarchies are two classes deep feels sort of like walking around a basement where the ceiling is too low with a flashlight looking for a crate. And so I'm guessing that this idea of splitting a protocol from its class has bled into Squeak from Objective-C in the form of Traits. Casimiro must have a reason for using them that he likes. But they do seem like a workaround as a result of a shallow hierarchy. I think I'd rather create my own abstract superclass to define an interface. Chris [1] http://www.metaobject.com/downloads/Squeak/ [2] "Masterminds Of Programming" (2009) O'Reilly, pg. 258-260. Brad Cox quotes: "Inheritance just isn't all that important. Encapsulation is OOP's lasting contribution." "Smalltalk didn't have anything like protocol in those days and that was added by Steve Naroff, who is now in charge of the Objective-C at Apple." "At first I used inheritance heavily, experimenting to find its bounds. Then I realized that encapsulation was the real contribution of OOP and that it could be used manually to do almost everything I'd been using inheritance for, but more cleanly."

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Re: Newbie Question: How does this work?
by Joseph J Alotta 10 Oct '12

10 Oct '12

I know I can make changes directly to String and add a method. But I was wondering if I can add a method to String and still keep the code in my Package. (I've made my own package/category called JJA that contains all the object that pertain to my program.) So is there a way to create a method in my own category for a class in another category? > Message: 4 > Date: Tue, 9 Oct 2012 16:16:59 +0100 > From: Frank Shearar <frank.shearar(a)gmail.com> > Subject: Re: [squeak-dev] Re: Newbie Question: How does this work? > To: The general-purpose Squeak developers list > <squeak-dev(a)lists.squeakfoundation.org> > Message-ID: > <CAJbhyRH3WgsMDdYWMvnkdBF770kV=nqOOyxz1ysYrk=w4u_Ygg(a)mail.gmail.com> > Content-Type: text/plain; charset=ISO-8859-1 > > On 9 October 2012 16:08, Joseph J Alotta <joseph.alotta(a)gmail.com> wrote: >> Thanks for you help. >> >> I see that String has a #printf and the protocol is *printf, and when the printf: method executes it looks everywhere for the FormatString class which is added to the end by the Printf package. >> >> So the question is how did the *printf protocols get added to String? It is not some magic by Monticello, because I did not use >> Monticello, I just filein-ed the code. >> >> So where in the code does it install the *printf methods to String? > > The original code (in what's called "chunk format") was incomplete. If > it had been complete (like the Printf Chris Cunnington's mentioned) > you'd have seen something like this: > > !String methodsFor: '*printf'! > printf: arguments > ^ self asFormatString printf: arguments! ! > > In Monticello these chunks are instead represented by MCDefinition subclasses. > > frank

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Re: [squeak-dev] The Trunk: Morphic-bf.627.mcz
by Chris Muller 10 Oct '12

10 Oct '12

I removed my Inbox submission (Morphic-cmm.442) for fixing this which you rejected in June 2010. I'm glad you finally found a solution that works for you. On Tue, Oct 9, 2012 at 5:01 PM, <commits(a)source.squeak.org> wrote: > Bert Freudenberg uploaded a new version of Morphic to project The Trunk: > http://source.squeak.org/trunk/Morphic-bf.627.mcz > > ==================== Summary ==================== > > Name: Morphic-bf.627 > Author: bf > Time: 9 October 2012, 3:00:33.903 pm > UUID: 2d7d0432-9723-4629-a850-3371eb3aca8b > Ancestors: Morphic-bf.626 > > For drawing rotated forms less than 32 bits deep, use Form paint rule. > > =============== Diff against Morphic-bf.626 =============== > > Item was changed: > ----- Method: FormCanvas>>transformBy:clippingTo:during:smoothing: (in category 'drawing-support') ----- > transformBy: aDisplayTransform clippingTo: aClipRect during: aBlock smoothing: cellSize > > "Note: This method has been originally copied from TransformationMorph." > | innerRect patchRect sourceQuad warp start subCanvas | > (aDisplayTransform isPureTranslation) ifTrue:[ > ^aBlock value: (self copyOffset: aDisplayTransform offset negated truncated > clipRect: aClipRect) > ]. > "Prepare an appropriate warp from patch to innerRect" > innerRect := aClipRect. > patchRect := (aDisplayTransform globalBoundsToLocal: innerRect) truncated. > sourceQuad := (aDisplayTransform sourceQuadFor: innerRect) > collect: [:p | p - patchRect topLeft]. > warp := self warpFrom: sourceQuad toRect: innerRect. > > "Render the submorphs visible in the clipping rectangle, as patchForm" > start := (self depth = 1 and: [self isShadowDrawing not]) > "If this is true B&W, then we need a first pass for erasure." > ifTrue: [1] ifFalse: [2]. > start to: 2 do: > [:i | "If i=1 we first make a shadow and erase it for opaque whites in B&W" > subCanvas := self class extent: patchRect extent depth: self depth. > i=1 ifTrue: [subCanvas shadowColor: Color black. > warp combinationRule: Form erase] > ifFalse: [self isShadowDrawing ifTrue: > [subCanvas shadowColor: self shadowColor]. > + warp combinationRule: (self depth = 32 > + ifTrue: [Form blendAlphaScaled] > + ifFalse: [Form paint])]. > - warp combinationRule: (self depth = 32 ifTrue: [Form blendAlphaScaled] ifFalse: [Form blend])]. > subCanvas > translateBy: patchRect topLeft negated > during: aBlock. > warp sourceForm: subCanvas form; cellSize: cellSize; warpBits. > warp sourceForm: nil. subCanvas := nil "release space for next loop"] > ! > >

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Daily Commit Log
by commits＠source.squeak.org 10 Oct '12

10 Oct '12

Changes to Trunk (http://source.squeak.org/trunk.html) in the last 24 hours: http://lists.squeakfoundation.org/pipermail/packages/2012-October/005534.ht… Name: Morphic-bf.626 Ancestors: Morphic-ul.625 Fix rotated drawing of translucent morphs. ============================================= http://lists.squeakfoundation.org/pipermail/packages/2012-October/005535.ht… Name: Morphic-bf.627 Ancestors: Morphic-bf.626 For drawing rotated forms less than 32 bits deep, use Form paint rule. =============================================

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The Trunk: Morphic-bf.627.mcz
by commits＠source.squeak.org 10 Oct '12

10 Oct '12

Bert Freudenberg uploaded a new version of Morphic to project The Trunk: http://source.squeak.org/trunk/Morphic-bf.627.mcz ==================== Summary ==================== Name: Morphic-bf.627 Author: bf Time: 9 October 2012, 3:00:33.903 pm UUID: 2d7d0432-9723-4629-a850-3371eb3aca8b Ancestors: Morphic-bf.626 For drawing rotated forms less than 32 bits deep, use Form paint rule. =============== Diff against Morphic-bf.626 =============== Item was changed: ----- Method: FormCanvas>>transformBy:clippingTo:during:smoothing: (in category 'drawing-support') ----- transformBy: aDisplayTransform clippingTo: aClipRect during: aBlock smoothing: cellSize "Note: This method has been originally copied from TransformationMorph." | innerRect patchRect sourceQuad warp start subCanvas | (aDisplayTransform isPureTranslation) ifTrue:[ ^aBlock value: (self copyOffset: aDisplayTransform offset negated truncated clipRect: aClipRect) ]. "Prepare an appropriate warp from patch to innerRect" innerRect := aClipRect. patchRect := (aDisplayTransform globalBoundsToLocal: innerRect) truncated. sourceQuad := (aDisplayTransform sourceQuadFor: innerRect) collect: [:p | p - patchRect topLeft]. warp := self warpFrom: sourceQuad toRect: innerRect. "Render the submorphs visible in the clipping rectangle, as patchForm" start := (self depth = 1 and: [self isShadowDrawing not]) "If this is true B&W, then we need a first pass for erasure." ifTrue: [1] ifFalse: [2]. start to: 2 do: [:i | "If i=1 we first make a shadow and erase it for opaque whites in B&W" subCanvas := self class extent: patchRect extent depth: self depth. i=1 ifTrue: [subCanvas shadowColor: Color black. warp combinationRule: Form erase] ifFalse: [self isShadowDrawing ifTrue: [subCanvas shadowColor: self shadowColor]. + warp combinationRule: (self depth = 32 + ifTrue: [Form blendAlphaScaled] + ifFalse: [Form paint])]. - warp combinationRule: (self depth = 32 ifTrue: [Form blendAlphaScaled] ifFalse: [Form blend])]. subCanvas translateBy: patchRect topLeft negated during: aBlock. warp sourceForm: subCanvas form; cellSize: cellSize; warpBits. warp sourceForm: nil. subCanvas := nil "release space for next loop"] !

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The Trunk: Morphic-bf.626.mcz
by commits＠source.squeak.org 09 Oct '12

09 Oct '12

Bert Freudenberg uploaded a new version of Morphic to project The Trunk: http://source.squeak.org/trunk/Morphic-bf.626.mcz ==================== Summary ==================== Name: Morphic-bf.626 Author: bf Time: 9 October 2012, 2:41:25.246 pm UUID: 358e353f-679b-4fa3-80d3-ac01ce47b766 Ancestors: Morphic-ul.625 Fix rotated drawing of translucent morphs. =============== Diff against Morphic-ul.625 =============== Item was changed: ----- Method: FormCanvas>>transformBy:clippingTo:during:smoothing: (in category 'drawing-support') ----- transformBy: aDisplayTransform clippingTo: aClipRect during: aBlock smoothing: cellSize "Note: This method has been originally copied from TransformationMorph." | innerRect patchRect sourceQuad warp start subCanvas | (aDisplayTransform isPureTranslation) ifTrue:[ ^aBlock value: (self copyOffset: aDisplayTransform offset negated truncated clipRect: aClipRect) ]. "Prepare an appropriate warp from patch to innerRect" innerRect := aClipRect. patchRect := (aDisplayTransform globalBoundsToLocal: innerRect) truncated. sourceQuad := (aDisplayTransform sourceQuadFor: innerRect) collect: [:p | p - patchRect topLeft]. warp := self warpFrom: sourceQuad toRect: innerRect. "Render the submorphs visible in the clipping rectangle, as patchForm" start := (self depth = 1 and: [self isShadowDrawing not]) "If this is true B&W, then we need a first pass for erasure." ifTrue: [1] ifFalse: [2]. start to: 2 do: [:i | "If i=1 we first make a shadow and erase it for opaque whites in B&W" subCanvas := self class extent: patchRect extent depth: self depth. i=1 ifTrue: [subCanvas shadowColor: Color black. warp combinationRule: Form erase] ifFalse: [self isShadowDrawing ifTrue: [subCanvas shadowColor: self shadowColor]. + warp combinationRule: (self depth = 32 ifTrue: [Form blendAlphaScaled] ifFalse: [Form blend])]. - warp combinationRule: Form paint]. subCanvas translateBy: patchRect topLeft negated during: aBlock. warp sourceForm: subCanvas form; cellSize: cellSize; warpBits. warp sourceForm: nil. subCanvas := nil "release space for next loop"] !

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how to halt through xpra?
by Craig Latta 09 Oct '12

09 Oct '12

Hi all-- Recently I've been running Squeak on remote machines, using xpra for a virtual display. I connect to the virtual display from an X server running on an Ubuntu virtual machine running in Parallels on my Mac laptop. It all works great, except for... I can't halt. The halt keybinding for my host platform (command-period) doesn't make it to Squeak through all the layers of keyboard event handling. I'm sure I'll figure something out, but I thought I'd first ask if anyone else has already taken some countermeasure they like. thanks! -C -- Craig Latta www.netjam.org/resume +31 6 2757 7177 + 1 415 287 3547 (no SMS)

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When does a Form become a standing window? (Or, why does my MicroSqueak window disappear?)
by Chris Cunnington 09 Oct '12

09 Oct '12

MicroSqueak [1] has a hierarchy of classes for making a tiny image. MForm in that hierarchy has a method: MForm>>beDisplayDepth: specialObjectsArray at: 15 put: self This is pretty neat. It says take the Form you made and make it the Form that is the Display. I run the 59K image with the Etoys 4.1 app to get an older virtual machine and a separate Mac OSX window appears. And then it disappears. Pop. I want it to stay. Don't go anywhere. I'm guessing a process like 'the UI Process' in the ProcessBrowser is required to create a loop to keep the window static on my desktop. Then again, maybe that process is just there to constantly poll for events to send to SmalltalkEditor. BitBlt class alphaBlendDemo is equally ephemeral. What's the difference between a Form that disappears on "restore display (r)" and a standing window? Thanks, Chris [1] http://web.media.mit.edu/~jmaloney/microsqueak/

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