Re: [Newbies] How to empty a collection?
On Feb 19, 2008, at 10:53 , Marcin Tustin wrote: Re-initialize how? I can't see a way to run object initialisation over again on an existing object. Everything in Smalltalk happens by sending a message. How was your object initialized? By sending a message. How can you initialize it again? Send the message again. Case in point - OrderedCollection. How is it initialized? Look at #new:. It sends #setCollection:. So send #setCollection: with a new Array and you're done. Well, of course you're not *supposed* to be doing this. But you could, and it would only be half-evil ;) - Bert - ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] Loading Rome SVG package
On Feb 19, 2008, at 0:47 , Marcin Tustin wrote: I can load the following packages out of the squeaksource repository: Rome-Balloon Rome-Base Rome-PluginCanvas Rome-SVG Rome-Strike Rome-Tests Rome-Reference Rome-BalloonCanvas The rest give me errors about lacking other classes, which I reproduce below. Are the packages that load enough to be useful, or am I going to be stuffed when playing around with Rome? You only need Rome-Base, Rome-Balloon, Rome-PluginCanvas to get started, provided you have the Rome plugin. To experiment without the plugin, load Rome-Reference and Rome-BalloonCanvas, too. This is actually noted on http://squeaksource.com/Rome.html The reason is that Rome supports several back-ends, the PluginCanvas uses Cairo, BalloonCanvas uses Balloon2D. If so, where should I get the dependencies? Also, there's a lack of class comments. Is there documentation elsewhere? Is Rome even ready to be used at all? Rome is used in the Sophie project. Rome-Demo also gives me a syntax error: fontFor: aCanvas family: aFamily style: aStyle has a full stop after the comment. After fixing this it gives me an error because RomeFreetypeCanvas is not recognised. Rome-Freetype seems to only live at http://source.impara.de/Rome.html (the repository used by the Sophie developers) Thanks all! Rome-Tweak depends on: This package depends on the following classes: CMatrixTransform CBitmapFill CTransformCanvas CDisplayTransform CCostumeFill CGraphicsFill CNoFill CIdentityTransform CProjectBuilder CSolidFill CGradientFill COffsetTransform These are Tweak classes. Ignore if you do not use Tweak. Rome-FontManager: This package depends on the following classes: FreetypeFontFace FreetypeFont The FontManager is Sophie-specific. It depends on Freetype: http://source.impara.de/freetype.html Rome-Plugin: This package depends on the following classes: SmartSyntaxInterpreterPlugin CCodeGenerator TSendNode This is the plugin source code, you need it only if you want to translate and compile your own plugin. - Bert - ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: [Seaside] Re: More Election nominations please!
tim == tim Rowledge [EMAIL PROTECTED] writes: tim I'll second that. We need to see more *serious* interest in running this tim community or it will fade into moribundity. I'd be happy to throw my hat into the ring, but I'm afraid of being laughed at for not having much more to contribute than 25 years of smalltalk experience and having followed squeak as an interested user since its first announcement. I also have a lot of experience promoting and supporting Perl, and I imagine that this might be useful to a Squeak board. So, would people consider my contributions useful? -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 [EMAIL PROTECTED] URL:http://www.stonehenge.com/merlyn/ Perl/Unix/security consulting, Technical writing, Comedy, etc. etc. See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training! ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] How to empty a collection?
My understanding as well is that this is the purpose of #become:, but also that it is not very efficient in some versions of Smalltalk. If you are using an OrderedCollection, this is probably a reasonably efficient method as it doesn't need to search through the whole list every time it removes an element: removeAll [self notEmpty] whileTrue: [self removeLast] Brian. On Feb 18, 2008 6:42 PM, Marcin Tustin [EMAIL PROTECTED] wrote: My own testing suggests that references to the object remain in place. I would guess that that is the whole point of become. On Feb 19, 2008 1:38 AM, cdrick [EMAIL PROTECTED] wrote: Isn't Cedrick's aida solution going to be significantly faster? this is not mine :) butI'd interested to see if it's a good use of #become:... Does it keep references ? is it safe ? Thanks ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: [Seaside] Re: More Election nominations please!
Ron == Ron Teitelbaum [EMAIL PROTECTED] writes: Ron I've read a number of your posts and consider you to be a very active Ron member of our community. I would think that you would be considered a Ron very serious candidate for the board. Are you declaring your candidacy? Then, yes. I would be happy to bring my contributions and abilities to the Squeak board to help preserve, develop, and promote Squeak. -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 [EMAIL PROTECTED] URL:http://www.stonehenge.com/merlyn/ Perl/Unix/security consulting, Technical writing, Comedy, etc. etc. See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training! ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: [Seaside] Re: More Election nominations please!
On 19/02/2008, Matthew Fulmer [EMAIL PROTECTED] wrote: On Mon, Feb 18, 2008 at 03:51:39PM -0800, tim Rowledge wrote: I'll second that. We need to see more *serious* interest in running this community or it will fade into moribundity. I love this community. I'll run for board. The biggest thing I want to make happen is serious compatibility between croquet and the squeak release. I also want a lot more communication between the board and the wider community. I can do that. So, I'll volunteer as a board candidate I've been asked by Ron to step up as a potential member of newly formed Technical board. My primary concern is to improve VM, make it shiny and polished, and don't canonize it too much. To be appeal for developers, squeak should show a constant progress in this area as well. We are at the rise of multi-core era, and squeak should respond on that with own, ultimate ways :) So, if you so dare to see some innovation in VM vote for me :) -- Best regards, Igor Stasenko AKA sig. ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] How to empty a collection?
Brian == Brian Murphy-Dye [EMAIL PROTECTED] writes: Brian My understanding as well is that this is the purpose of #become:, but Brian also that it is not very efficient in some versions of Smalltalk. If Brian you are using an OrderedCollection, this is probably a reasonably Brian efficient method as it doesn't need to search through the whole list Brian every time it removes an element: Brian removeAll Brian [self notEmpty] whileTrue: [self removeLast] What makes you think #removeLast doesn't need to search through the whole list in some kinds of OrderedCollection? You *do* have an implementation assumption there. I'd just do: removeAll self notEmpty ifTrue: [self become: self species new]. and let subclasses make it more efficient using implementation knowledge. -- Randal L. Schwartz - Stonehenge Consulting Services, Inc. - +1 503 777 0095 [EMAIL PROTECTED] URL:http://www.stonehenge.com/merlyn/ Perl/Unix/security consulting, Technical writing, Comedy, etc. etc. See PerlTraining.Stonehenge.com for onsite and open-enrollment Perl training! ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] How to empty a collection?
[EMAIL PROTECTED] wrote: The *normal* way people usually do it thoiugh is to *not depend on the identity* of the Collection - different objects should typically not share the same Collection. And if you don't share - then the easy way out is to just do: myCollection := OrderedCollection new or whatever class you use ...in order to empty it. A word of caution: identity should be preserved in the 'normal' case, replacing with another collection should be regarded as the exceptional case. Your assertion that different objects should typically not share the same Collection. is only valid in limited cases. I'm talking from my experience with building mvc-based apps on VisualWorks. Code needs to be decoupled, ie 'model' objects and collections should not know about the UI's that are coupled to them, this is achieved with the various dependency mechanisms available in VW. Changing identity of the collections will break this paradigm big time (regardless of whether the dependents are managed in a global dictionary or by the collection itself). As to the implementation of #removeAll on non-growable collections: follow whatever pattern the squeak library uses for other messages that alter the size (#add:, #remove:,...). In VW the idiom is to call #shouldNotImplement. Cheers, R - ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] How to empty a collection?
On Feb 19, 2008, at 16:06 , cdrick wrote: So, following Bert suggestion, would it be possible to change removeAll: from... I'm pretty certain I did not suggest anything like this. Nothing is broken here, so let's not fix it. A new feature would be adding #removeAll, which sounds reasonable¹. - Bert - ¹I do smell a bit of premature optimization here, or does anyone have a really convincing use case? ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: Re: How to empty a collection?
On Tue, 19 Feb 2008 17:21:57 +0100, Klaus D. Witzel wrote: On Tue, 19 Feb 2008 16:56:48 +0100, cdrick wrote: Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Thumbs down, I do not want anybody copy a collection behind my back (however small or large it is) just because remove* has nothing to do with copy. Ok, I can understand. What about the error ? This is a bug, Smalltalk cannot compromise its fundamental structures (#removeAll is ANSI). Enter the report if not already on mantis attach your fix. Sorry, s/#removeAll /#removeAll: / /Klaus ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
On Tue, 19 Feb 2008 16:06:50 +0100, cdrick wrote: ... I forgot that in my first attemp (and I knew that !)... col := #(1 2 3) asOrderedCollection. col removeAll: col. ^col returns an OrderedCollection(2) col removeAll: col copy is ok. So, following Bert suggestion, would it be possible to change removeAll: from... removeAll: aCollection aCollection do: [:each | self remove: each]. ^ aCollection to removeAll: aCollection aCollection copy do: [:each | self remove: each]. ^ aCollection or removeAll: aCollection aCollection == self ifTrue: [aCollection copy do: [:each | self remove: each]] ifFalse: [aCollection do: [:each | self remove: each]]. ^ aCollection or again removeAll: aCollection aCollection == self ifTrue: [self removeAll: aCollection copy] ifFalse: [aCollection do: [:each | self remove: each]]. Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Thumbs down, I do not want anybody copy a collection behind my back (however small or large it is) just because remove* has nothing to do with copy. Cédrick ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: Re: How to empty a collection?
On Tue, 19 Feb 2008 16:56:48 +0100, cdrick wrote: Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Thumbs down, I do not want anybody copy a collection behind my back (however small or large it is) just because remove* has nothing to do with copy. Ok, I can understand. What about the error ? This is a bug, Smalltalk cannot compromise its fundamental structures (#removeAll is ANSI). Enter the report if not already on mantis attach your fix. /Klaus ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] How to empty a collection?
Hi! Reinout Heeck [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] wrote: The *normal* way people usually do it thoiugh is to *not depend on the identity* of the Collection - different objects should typically not share the same Collection. And if you don't share - then the easy way out is to just do: myCollection := OrderedCollection new or whatever class you use ...in order to empty it. A word of caution: identity should be preserved in the 'normal' case, I agree. While I still think relying too much on identities is a dangerous practice. replacing with another collection should be regarded as the exceptional case. Your assertion that different objects should typically not share the same Collection. is only valid in limited cases. Well, I still stand by it as a general nice rule. :) I'm talking from my experience with building mvc-based apps on VisualWorks. Code needs to be decoupled, ie 'model' objects and collections should not know about the UI's that are coupled to them, this is achieved with the various dependency mechanisms available in VW. I know, I used VW back in the 2.5-3.x days and while I first thought the adapter-frenzy was cool I later also started thinking it was over-engineered as hell. ;) Changing identity of the collections will break this paradigm big time (regardless of whether the dependents are managed in a global dictionary or by the collection itself). Yes, if your adapters/UI components etc cling onto the collections themselves, then yes, you will be bitten big time. I still think that paradigm is fishy - but again, I only presented the way people *typically* go about this thing - I still of course would like to preserve identity and introduce #removeAll. It is better in all respects. If the *intent* is to remove all elements - then the message should state exactly that intent. Doing stuff like aColl copy do: [:each | aColl remove: each] is just plain dumb and silly, though it would probably qualify as a default implementation in class Collection. :) regards, Göran ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] How to empty a collection?
[EMAIL PROTECTED] (Randal L. Schwartz) wrote: Brian == Brian Murphy-Dye [EMAIL PROTECTED] writes: Brian My understanding as well is that this is the purpose of #become:, but Brian also that it is not very efficient in some versions of Smalltalk. If Brian you are using an OrderedCollection, this is probably a reasonably Brian efficient method as it doesn't need to search through the whole list Brian every time it removes an element: Brian removeAll Brian [self notEmpty] whileTrue: [self removeLast] What makes you think #removeLast doesn't need to search through the whole list in some kinds of OrderedCollection? You *do* have an implementation assumption there. I'd just do: removeAll self notEmpty ifTrue: [self become: self species new]. and let subclasses make it more efficient using implementation knowledge. I would never use become: in regular code like this. :) regards, Göran ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Looking back... (was Re: [Newbies] How to empty a collection?)
Hi all! Ok, since this was discussed AT PAINFULLY GREAT LENGTH back in aug/sept 2002 I just wanted to give you some reading on the subject at hand. Don't *ever* presume the issue you are bringing attention to hasn't been argued to death already :) :) Threads of discussions related to this from 2002: http://lists.squeakfoundation.org/pipermail/squeak-dev/2002-August/04315 7.html http://lists.squeakfoundation.org/pipermail/squeak-dev/2002-September/04 3926.html http://lists.squeakfoundation.org/pipermail/squeak-dev/2002-September/04 3928.html Especially Richard O Keefe did an awesome job back then IIRC. Now, if those threads will not exhaust you completely :) - then feel free to hack up a changeset that is a conclusion of all findings in there. :) regards, Göran ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] Re: Re: How to empty a collection?
Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Thumbs down, I do not want anybody copy a collection behind my back (however small or large it is) just because remove* has nothing to do with copy. Ok, I can understand. What about the error ? This is a bug, Smalltalk cannot compromise its fundamental structures (#removeAll is ANSI). Enter the report if not already on mantis attach your fix. I actually didn't meant it was a bug :) I need to be sharper with my english... I meant raising an error message if self == aCollection ... Could it be a fix ? Because in a way, the behavior is not really an error, it's more a bad use because we know it's iterative and then, self and aCollection change in the same time... I hope you don't take my remarks, as I want to change smalltalk... I just want to understand it better ;) Cheers Cédrick ps: by the way, I'll open a bug report, as finally I think it's an error (arf) because I shouldn't be aware removeAll is iterativeetc... so here is the bug report (http://bugs.squeak.org/view.php?id=6937). ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: Looking back... (was Re: [Newbies] How to empty a collection?)
Hi Goran! I just want to point out that the long links in your mail were broken for me (although a little cut and paste fixed that). Perhaps a service like tinyURL would be useful when sending long links from the dark and distant past. I have noticed in this thread an undertone of #become is the Devil's playground Could someone succinctly explain to someone who is a coarse and styless programmer like myself why this is so, and when its use is justified? Thanks, John (keeping the newb in newbie for many years now) Hi all! Ok, since this was discussed AT PAINFULLY GREAT LENGTH back in aug/sept 2002 I just wanted to give you some reading on the subject at hand. Don't *ever* presume the issue you are bringing attention to hasn't been argued to death already :) :) Threads of discussions related to this from 2002: http://lists.squeakfoundation.org/pipermail/squeak-dev/2002-August/04315 7.html http://lists.squeakfoundation.org/pipermail/squeak-dev/2002-September/04 3926.html http://lists.squeakfoundation.org/pipermail/squeak-dev/2002-September/04 3928.html snip regards, Göran ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
cdrick a écrit : or again removeAll: aCollection aCollection == self ifTrue: [self removeAll: aCollection copy] ifFalse: [aCollection do: [:each | self remove: each]]. Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Cédrick aCollection == self is not the only case that can fail. Imagine i pass a wrapper collection on self, like a MappedCollection. When i will change self with remove:, i will also change the argument which is just a wrapper on self. Hope my explanations are not too much confusing... Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
On Tue, 19 Feb 2008 21:01:14 +0100, nicolas cellier wrote: cdrick a écrit : or again removeAll: aCollection aCollection == self ifTrue: [self removeAll: aCollection copy] ifFalse: [aCollection do: [:each | self remove: each]]. Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Cédrick aCollection == self is not the only case that can fail. Imagine i pass a wrapper collection on self, like a MappedCollection. When i will change self with remove:, i will also change the argument which is just a wrapper on self. Hope my explanations are not too much confusing... Let's see: Remove each element of aCollection from the receiver. If successful for each, answer aCollection. Otherwise create an error notification. What mapping would *not* raise the error notification ;-) BTW: MappedCollection does not exist in sq3.10-7159dev08.02.1.image ... /Klaus Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: Looking back... (was Re: [Newbies] How to empty a collection?)
On Feb 20, 2008 8:47 AM, [EMAIL PROTECTED] wrote: Hi Goran! I just want to point out that the long links in your mail were broken for me (although a little cut and paste fixed that). Perhaps a service like tinyURL would be useful when sending long links from the dark and distant past. I have noticed in this thread an undertone of #become is the Devil's playground Could someone succinctly explain to someone who is a coarse and styless programmer like myself why this is so, and when its use is justified? Hi John the Newbie. It would be appreciated if you replied under a quoted message rather than above it. I've just sent an email in the original thread about this. It's use would only be justified if there are no other options. I've used it myself in my remote object architecture[1] for converting a message-capturing object proxy into the original object when an object is migrated between computers. My intention was to keep the remoteness of the objects involved as hidden as possible, making the use of #become: necessary. In retrospect, it was a big and dangerous time-waster. Many images died to bring me this information. Originally, the Collections framework in Squeak used become: to grow some collections. The blue book design of the Smalltalk VM[2] has an object lookup table where the implementation of #become: was very fast - switch a single pointer. The Squeak VM uses direct pointers between objects now, so the entire object memory needs to be scanned. [1] http://www.gulik.co.nz/dpon_design.pdf, http://www.squeaksource.com/DPON . [2] http://users.ipa.net/~dwighth/smalltalk/bluebook/bluebook_imp_toc.html Gulik. -- http://people.squeakfoundation.org/person/mikevdg http://gulik.pbwiki.com/ ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] How to empty a collection?
On Feb 20, 2008 8:09 AM, Randal L. Schwartz [EMAIL PROTECTED] wrote: goran == goran [EMAIL PROTECTED] writes: I'd just do: removeAll self notEmpty ifTrue: [self become: self species new]. and let subclasses make it more efficient using implementation knowledge. goran I would never use become: in regular code like this. :) First, how regular is it if the method hasn't been missed by anyone in 27 years. :) Second, what are you objecting to? #become: is clearly a part of the image, and works fine. This code also cleans out a grown collection to be the smallest it possiby can become, where delete-one-at-a-time solutions don't. #become: and its friends are voodoo. Don't use them in your code unless you have absolutely no other option. It doesn't work fine. It breaks code that relies on hashes; specifically, a Dictionary elsewhere in your image can start acting screwy if you do a #become: variant that doesn't preserve an object's hash. See #becomeForwardcopyHash:. You would then also be relying on a Squeakish behaviour and your code would become less portable across Smalltalk dialects. They are also a fantastic way to introduce bugs of various sorts, and can even cause an image to crash (as in, stack trace and exit to the OS). Say, for example, that one of the arguments you pass is accidently nil, true or false? Your image would continue working... for a while. #become: and variants are also very slow and causes the equivalent of a full GC on every invocation. Gulik. -- http://people.squeakfoundation.org/person/mikevdg http://gulik.pbwiki.com/ ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: [Squeak 0006937]: removeAll: aCollection doesn't do what we expect if aCollection==self
Hi nicolas, in your counter example you have forgotten that this bug is about failure of removal, but your example does not fail, instead it removes all elements (in Squeak 3.9, where MappedCollection still exists). Can you tell us why? And please only add code to bug reports which does what you claim; things which don't work can be discussed here :) /Klaus On Tue, 19 Feb 2008 21:28:25 +0100 a NOTE has been added to this issue: == http://bugs.squeak.org/view.php?id=6937 == Reported By:cdrick Assigned To: == Project:Squeak Issue ID: 6937 Category: Collections Reproducibility:always Severity: minor Priority: normal Status: new == Date Submitted: 02-19-2008 18:12 UTC Last Modified: 02-19-2008 20:28 UTC == Summary:removeAll: aCollection doesn't do what we expect if aCollection==self Description: This known error has had a revival originating from a mail of Sophie in the beginnner list... and I ended up opening a bug report... The problem is: col := #(1 2 3) asOrderedCollection. col removeAll: col. ^col returns an OrderedCollection(2) instead of an empty one as we would expect... == -- kwl - 02-19-08 18:51 -- OrderedCollection-removeAll-kwl-6937.st tested with the 441 cases in the CollectionTests category, all green. -- nicolas cellier - 02-19-08 20:28 -- As posted in beginners list, self == aCollection does not handle case when aCollection is just a wrapper on self... So the change won't removeAll problems... in a 3.9 image try this: | collec1 collec2 | collec1 := OrderedCollection with: 'a' with: 'b' with: 'c'. collec2 := MappedCollection collection: collec1 map: (3 to: 1 by: -1). collec1 removeAll: collec2. collec1 inspect Agree, yet, the problem lies in super... Note: MappedCollection was removed from 3.10, but in spirit there can be other wrapper collections (i used some myself). Issue History Date Modified Username FieldChange == 02-19-08 18:12 cdrick New Issue 02-19-08 18:51 kwlFile Added: OrderedCollection-removeAll-kwl-6937.st 02-19-08 18:51 kwlNote Added: 0011843 02-19-08 20:28 nicolas cellierNote Added: 0011846 == ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
Klaus D. Witzel a écrit : On Tue, 19 Feb 2008 21:01:14 +0100, nicolas cellier wrote: cdrick a écrit : or again removeAll: aCollection aCollection == self ifTrue: [self removeAll: aCollection copy] ifFalse: [aCollection do: [:each | self remove: each]]. Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Cédrick aCollection == self is not the only case that can fail. Imagine i pass a wrapper collection on self, like a MappedCollection. When i will change self with remove:, i will also change the argument which is just a wrapper on self. Hope my explanations are not too much confusing... Let's see: Remove each element of aCollection from the receiver. If successful for each, answer aCollection. Otherwise create an error notification. What mapping would *not* raise the error notification ;-) My interpretation of the comment was rather for the case when we try to remove an element which is not in the collection... But OK, I take it as is... However i can construct a test case that will not do what is expected and will not raise a notification, wanna bet? | collec1 collec2 | collec1 := OrderedCollection with: 'a' with: 'b' with: 'c'. collec2 := MappedCollection collection: collec1 map: (1 to: 2). collec2 only map first two elements 'a' and 'b' collec1 removeAll: collec2. this should remove 'a' and 'b' from collec1 self assert: collec1 first = 'c' too bad... it's 'b' BTW: MappedCollection does not exist in sq3.10-7159dev08.02.1.image ... MappedCollection is just an example of possible wrapper collection, even if there is none in core images nowadays, that's a classical pattern which avoid copying for example. MappedCOllection is in 3.9 image. /Klaus Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Recap: How to empty a collection
I've been following this debate with some interest, but I think it's gone beyond a noob discussion. Is there a noob answer to this question? There ought to be. I'm sort of leaning toward: Q. How do you empty a collection. A. You don't, you replace it with a new instance. Q. What if you have references to the collection in multiple places? A. Wrap the collection in another class, and reference that. ?? ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: Recap: How to empty a collection
On Tue, 19 Feb 2008 22:14:49 +0100, Blake wrote: I've been following this debate with some interest, but I think it's gone beyond a noob discussion. Is there a noob answer to this question? There ought to be. I'm sort of leaning toward: Q. How do you empty a collection. A. You don't, you replace it with a new instance. Q. What if you have references to the collection in multiple places? A. Wrap the collection in another class, and reference that. ?? Q. can I use #become: instead of wrapper? A. yes but the pro's don't like solutions with #become:, it smells /Klaus ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
On Tue, 19 Feb 2008 22:00:09 +0100, nicolas cellier wrote: Klaus D. Witzel a écrit : On Tue, 19 Feb 2008 21:01:14 +0100, nicolas cellier wrote: cdrick a écrit : or again removeAll: aCollection aCollection == self ifTrue: [self removeAll: aCollection copy] ifFalse: [aCollection do: [:each | self remove: each]]. Or maybe, if aCollection == self, a warning could be raised ? What do you think ? Cédrick aCollection == self is not the only case that can fail. Imagine i pass a wrapper collection on self, like a MappedCollection. When i will change self with remove:, i will also change the argument which is just a wrapper on self. Hope my explanations are not too much confusing... Let's see: Remove each element of aCollection from the receiver. If successful for each, answer aCollection. Otherwise create an error notification. What mapping would *not* raise the error notification ;-) My interpretation of the comment was rather for the case when we try to remove an element which is not in the collection... But OK, I take it as is... However i can construct a test case that will not do what is expected and will not raise a notification, wanna bet? No, just let the next people who attempt to bring MappedCollection back to Squeak 3.10 take care ;-) BTW: do you have as much energy for fixing problems as you seem to have for imagine the currently non-existing ;-) This would help Squeak jump forward :) | collec1 collec2 | collec1 := OrderedCollection with: 'a' with: 'b' with: 'c'. collec2 := MappedCollection collection: collec1 map: (1 to: 2). collec2 only map first two elements 'a' and 'b' collec1 removeAll: collec2. this should remove 'a' and 'b' from collec1 self assert: collec1 first = 'c' too bad... it's 'b' BTW: MappedCollection does not exist in sq3.10-7159dev08.02.1.image ... MappedCollection is just an example of possible wrapper collection, even if there is none in core images nowadays, that's a classical pattern which avoid copying for example. MappedCOllection is in 3.9 image. /Klaus Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] Re: Recap: How to empty a collection
On Feb 19, 2008, at 10:36 PM, Klaus D. Witzel wrote: On Tue, 19 Feb 2008 22:14:49 +0100, Blake wrote: I've been following this debate with some interest, but I think it's gone beyond a noob discussion. Is there a noob answer to this question? There ought to be. I'm sort of leaning toward: Q. How do you empty a collection. A. You don't, you replace it with a new instance. Q. What if you have references to the collection in multiple places? A. Wrap the collection in another class, and reference that. ?? Q. can I use #become: instead of wrapper? A. yes but the pro's don't like solutions with #become:, it smells and it's slow in Squeak. /Klaus ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners Mth ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: How to empty a collection?
Klaus D. Witzel a écrit : On Tue, 19 Feb 2008 22:00:09 +0100, nicolas cellier wrote: However i can construct a test case that will not do what is expected and will not raise a notification, wanna bet? No, just let the next people who attempt to bring MappedCollection back to Squeak 3.10 take care ;-) As a user of collection wrappers, proposed patch just hit the alarm buzzer my nervous brain is equipped with. But your position is wise. As long as a MappedCollection, lazy list or lazy collection (see these projects on SqueakSource) are all created under our control, we can manage... BTW: do you have as much energy for fixing problems as you seem to have for imagine the currently non-existing ;-) This would help Squeak jump forward :) That's precisely how i find and fix unknown bugs: Imagine how i could break current implementation. For this reason, most patches i proposed are minor. Hope a few are usefull, since adopted in 3.8.1, 3.9 and 3.10. Any minor contribution counts anyway :) Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] Re: Recap: How to empty a collection
On Tue, 19 Feb 2008 14:20:51 -0800, Mathieu Suen [EMAIL PROTECTED] wrote: On Feb 19, 2008, at 10:36 PM, Klaus D. Witzel wrote: On Tue, 19 Feb 2008 22:14:49 +0100, Blake wrote: I've been following this debate with some interest, but I think it's gone beyond a noob discussion. Is there a noob answer to this question? There ought to be. I'm sort of leaning toward: Q. How do you empty a collection. A. You don't, you replace it with a new instance. Q. What if you have references to the collection in multiple places? A. Wrap the collection in another class, and reference that. ?? Q. can I use #become: instead of wrapper? A. yes but the pro's don't like solutions with #become:, it smells and it's slow in Squeak. Well, from what I was reading, slow and smells is putting it too mildly. It sounds like it can corrupt your image, i.e., leave you with non-working objects in unexpected places. I wouldn't even mention it. ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: Recap: How to empty a collection
Blake a écrit : Well, from what I was reading, slow and smells is putting it too mildly. It sounds like it can corrupt your image, i.e., leave you with non-working objects in unexpected places. I wouldn't even mention it. Huh? Have a proof of what you wrote? ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] Re: Recap: How to empty a collection
On Tue, 19 Feb 2008 15:08:56 -0800, nicolas cellier [EMAIL PROTECTED] wrote: Blake a écrit : Well, from what I was reading, slow and smells is putting it too mildly. It sounds like it can corrupt your image, i.e., leave you with non-working objects in unexpected places. I wouldn't even mention it. Huh? Have a proof of what you wrote? Proof? None at all. I just have this, by Gulik: [become:] doesn't work fine. It breaks code that relies on hashes; specifically, a Dictionary elsewhere in yo ur image can start acting screwy if you do a #become: variant that doesn't preserve an object's hash. See #becomeForwardcopyHash:. You would then also be relying on a Squeakish behaviour and your code would become less portable across Sm alltalk dialects. They are also a fantastic way to introduce bugs of various sorts, and can even cause an image to crash (as in, stack trace and exit to the OS). Say, for example, that one of the arguments you pass is accidently nil, true or false? Your image would c ontinue working... for a while. Does this sound like something a newbie should use? No, it does not. ===Blake=== ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] How to empty a collection?
[EMAIL PROTECTED] (Randal L. Schwartz) wrote: goran == goran [EMAIL PROTECTED] writes: I'd just do: removeAll self notEmpty ifTrue: [self become: self species new]. and let subclasses make it more efficient using implementation knowledge. goran I would never use become: in regular code like this. :) First, how regular is it if the method hasn't been missed by anyone in 27 years. :) Second, what are you objecting to? #become: is clearly a part of the image, and works fine. This code also cleans out a grown collection to be the smallest it possiby can become, where delete-one-at-a-time solutions don't. And, if there's a more efficient thing for subclasses, they can certainly override it. Yes, I probably agree it would be a nice default implementation. Modulo someone now telling us we missed something of course. :) regards, Göran ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] Re: Recap: How to empty a collection
On Tue, 19 Feb 2008 15:19:40 -0800, nicolas cellier [EMAIL PROTECTED] wrote: But become: is still essential for operations like growing the MethodDictionary when you add new methods to a class, or migrate allInstances when you a or remove an instance variable to a class, to name few. So, it is not bogus. Just handle with care. OK. Does a newbie need to use it? To empty a collection? (Or whatever?) I'm trying to get at what should be a very simple thing without going to the metal, as it were. One thing I wasn't clear on is whether Bert's suggestion: aColl removeAllSuchThat: [:anElement| true]. Is okay, and why it's okay while many of the other similar approaches were not. ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] [Election 2008] Nominations soon ended - presentations and QA coming up!
Hi all! Ok, we have 11 candidates so far! Perfect. Now the first phase - Nominations - ends on the 22nd and then the campaigning period starts: 22nd to 25th: Candidates present themselves and their candidacy, preferrably by posting an article on SqP: http://people.squeakfoundation.org During this period I also urge you to look at the 10 questions we have cooked up for the candidates at: http://wiki.squeak.org/squeak/6029 ...and if you feel some important question is missing - email me in private and I will (if I think it is a good thing) put it in the last 5 open slots. First 5 served, then it is full! Deadline for sending me extra questions is the 24th. 25th to 29th: Candidates will answer (or not!) the questions by posting to squeak-dev. Feel free to discuss at length of course, the posts from the candidates will be added by me to the Swiki page so that all answers can be seen in one place. As always, election details are at: http://wiki.squeak.org/squeak/6025 regards, Göran PS. IMPORTANT: In order to vote - be sure to confirm that you have an account on people.squeakfoundation.org and that your email address is up to date. If you are not already registered on the site do so as soon as possible. Include information about your participation in the Squeak community to aid everyone in determining your appropriate certification. If you have misplaced your people.squeakfoundation.org password there is a link on the login page to allow you to reset it. When the voting period starts all voters will receive an email with instructions and a link to the voting website. ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: Recap: How to empty a collection
Blake a écrit :
On Tue, 19 Feb 2008 15:08:56 -0800, nicolas cellier
[EMAIL PROTECTED] wrote:
Blake a écrit :
Well, from what I was reading, slow and smells is putting it too
mildly. It sounds like it can corrupt your image, i.e., leave you
with non-working objects in unexpected places. I wouldn't even
mention it.
Huh?
Have a proof of what you wrote?
Proof? None at all. I just have this, by Gulik:
[become:] doesn't work fine. It breaks code that relies on hashes;
specifically, a Dictionary elsewhere in yo ur image can start acting
screwy if you do a #become: variant that doesn't preserve an object's
hash. See #becomeForwardcopyHash:. You would then also be relying on a
Squeakish behaviour and your code would become less portable across Sm
alltalk dialects.
I see, become: does exchange #identityHash, and that makes our
IdentityDictionary work, god thanks, but there is no such provision for
ordinary #hash and Dictionary...
However, there are plenty of ordinary things that would have the same
result:
| key1 key2 dic |
key1 := 'abc' copy.
key2 := 'abd' copy.
dic := Dictionary new.
dic at: key1 put: 1.
dic at: key2 put: 2.
key1 at: 1 put: $z.
{dic includesKey: key1.
dic keys includes: key1.}
So i propose newbies do not use #at:put: considering the danger about
Dictionary not finding their keys...
That's too much.
becomeForward: is squeakish, but the thread was about Squeak
implementation of a core library...
A rule is to use becomeForward: only with a just created object as argument.
But right, that's just too much for this thread.
They are also a fantastic way to introduce bugs of various sorts, and
can even cause an image to crash (as in, stack trace and exit to the
OS). Say, for example, that one of the arguments you pass is accidently
nil, true or false? Your image would c ontinue working... for a while.
Does this sound like something a newbie should use? No, it does not.
===Blake===
OK, good lesson, thank you.
Handle with care.
Try finding better patterns.
Protect usage (don't use with an unknow argument).
It smells.
I agree.
But don't pretend it's broken please.
Anyway, why do you think all code is accessible in Smalltalk?
In the spirit, nothing is to be hidden from newbies eyes.
Yes I know, maybe some code should
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Re: [Newbies] Re: Recap: How to empty a collection
On Tue, 19 Feb 2008 15:59:57 -0800, nicolas cellier [EMAIL PROTECTED]
wrote:
However, there are plenty of ordinary things that would have the same
result:
| key1 key2 dic |
key1 := 'abc' copy.
key2 := 'abd' copy.
dic := Dictionary new.
dic at: key1 put: 1.
dic at: key2 put: 2.
key1 at: 1 put: $z.
{dic includesKey: key1.
dic keys includes: key1.}
So i propose newbies do not use #at:put: considering the danger about
Dictionary not finding their keys...
This seems pretty bad to me, too, but it seems more designed to break a
known weakness than to actually accomplish something. You know, like empty
a collection.s
But I'd probably argue that the above should work, and that it's a design
flaw that it doesn't.
Anyway, why do you think all code is accessible in Smalltalk?
In the spirit, nothing is to be hidden from newbies eyes.
Yes I know, maybe some code should
There's a positive fetish about this. I'm all for everything being
accessible. But everything being equally accessible all the time is not
pragmatic.
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RE: [Newbies] How to empty a collection?
Well, of course you're not *supposed* to be doing this. But you could, and it would only be half-evil ;) It wouldn't be evil at all. This is Smalltalk, not Ada!! But seriously, it seems a major oversight that such a basic task isn't in the standard protocol. The language has been around a while, someone else must have wanted to empty a collection. -- Jeffrey Straszheim http://straszheim.50megs.com It not being standardized just means there's no consensus to the *right* way to do it. I'd bet many of us have our own versions of #removeAll in our images, I know I do. Ramon Leon http://onsmalltalk.com ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: Recap: How to empty a collection
Blake a écrit :
On Tue, 19 Feb 2008 15:59:57 -0800, nicolas cellier
[EMAIL PROTECTED] wrote:
However, there are plenty of ordinary things that would have the same
result:
| key1 key2 dic |
key1 := 'abc' copy.
key2 := 'abd' copy.
dic := Dictionary new.
dic at: key1 put: 1.
dic at: key2 put: 2.
key1 at: 1 put: $z.
{dic includesKey: key1.
dic keys includes: key1.}
So i propose newbies do not use #at:put: considering the danger about
Dictionary not finding their keys...
This seems pretty bad to me, too, but it seems more designed to break a
known weakness than to actually accomplish something. You know, like
empty a collection.s
Yes, the example is dumb, but that's the kind of thing that happens in
real code (just split contructing/changing keys/accessing in three
different methods).
No use to forbid become: for this reason, there are better reasons (it's
slw), become: usage was sponsored once upon a time when it was fast,
providing both efficient and generic solutions.
But I'd probably argue that the above should work, and that it's a
design flaw that it doesn't.
Yes, but it is very hard to make it work efficiently.
So that's a limitation we must be aware of.
Anyway, why do you think all code is accessible in Smalltalk?
In the spirit, nothing is to be hidden from newbies eyes.
Yes I know, maybe some code should
There's a positive fetish about this. I'm all for everything being
accessible. But everything being equally accessible all the time is not
pragmatic.
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Re: [Newbies] Re: Recap: How to empty a collection
On Feb 20, 2008 2:17 PM, nicolas cellier [EMAIL PROTECTED] wrote: Blake a écrit : On Tue, 19 Feb 2008 15:59:57 -0800, nicolas cellier [EMAIL PROTECTED] wrote: snip Could we please move this discussion to squeak-dev please? We're going to scare the beginners. Gulik. -- http://people.squeakfoundation.org/person/mikevdg http://gulik.pbwiki.com/ ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] More Morphic Fun
I want to create a container -- a panel -- that will contain other Morphs, but within which I can drag the morphs around. If the more were dragged out from the container it should be deleted. What is the most straightforward way to do this? Drag and drop? -- Jeffrey Straszheim http://straszheim.50megs.com ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
[Newbies] Re: Recap: How to empty a collection
On Wed, 20 Feb 2008 02:01:49 +0100, nicolas cellier wrote: ... Bert's suggestion is simple and works well. The only question is about efficiency. Up to (Down to?) subclasses to optimize it. Some proposed an alternative based on (self removeAll: self), and started writing optimized versions of #removeAll:. No, (anOrderedCollection removeAll: anOrderedCollection) was not optimized. It had a *very* long known bug, which was fixed. Please do less mixing of subjects in threads. I think our biggest problem is that we have plenty possible ways to do it... Finding a balance between genericity and efficiency... No, more correctness at the price of less efficiency :) Nicolas ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
Re: [Newbies] More Morphic Fun
Jeffrey Straszheim wrote: I want to create a container -- a panel -- that will contain other Morphs, but within which I can drag the morphs around. If the more were dragged out from the container it should be deleted. What is the most straightforward way to do this? Drag and drop? Use a PasteUpMorph which is the one used as the desktop. Use mouseLeave to do the delete. Karl ___ Beginners mailing list Beginners@lists.squeakfoundation.org http://lists.squeakfoundation.org/mailman/listinfo/beginners
