Squeak-dev March 2006

squeak-dev@lists.squeakfoundation.org

177 participants
255 discussions

veryDeepCopy, ImageSegments, and actionMaps
by Ned Konz 17 Aug '23

17 Aug '23

Any Object can have dependents whether or not it has an instance variable to keep track of them (these are kept in the DependentsFields class variable of Object). The only class that keeps its own dependents is Model. Any Object can have an actionMap. These are supplied by EventManager class by default, and are stored in the ActionMaps class variable of EventManager. The only class that keeps its own action maps is Morph. When we veryDeepCopy an object we also copy the global dependents (see DeepCopier>>fixDependents). However, we don't copy the actionMap in those cases where it's held by the EventManager class. When we file out an object that uses DependentsFields out into an ImageSegment, we also file out the dependents (see ImageSegment>>dependentsSave:) if it's in a project. We do this by adding a project parameter called #GlobalDependentsInProject. However, we don't file out the actionMap in those cases where it's held by the EventManager class. My question is this: should we fix these behaviors (copying and serialization) to include these "global action maps" just like we already include the "global dependents"? Or should we discourage the use of the "global action maps"? -- Ned Konz http://bike-nomad.com GPG key ID: BEEA7EFE

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Trying to build SerialPlugin for IrDA under MPW (MacOS 8.6)
by Hans-Martin Mosner 24 May '12

24 May '12

Hi, I recently got a serial IrDA adapter and wanted to play around with it under Squeak. This adapter has a baudrate switching mechanism which depends on toggling the DTR and RTS lines in the correct sequence. To support this, I wanted to build a new SerialPlugin with an additional primitive. However, the plugin as built with MPW does not seem to be accepted by the VM, which still uses the internal plugin in all cases. I've tried placing the plugin in a 'Plugins' subfolder of the VM's folder, and then directly into the VM folder, without any success. I have considered placing debug outputs in appropriate places in the VM, but building a complete VM with MPW is not easy - I would have to create an MPW makefile for the whole shebang, which is more work than I can invest at the moment. Does any of you Mac aficionados have an idea where the problem could be? I have appended the plugin and corresponding source files in a ZIP file (it's not big) so if you want to try it out you could do it right now :-) BTW, would it make sense to incorporate support for switching serial port parameters of an open port into the standard plugin? Closing and opening a port just to change the baud rate seems a little overkill... Cheers, Hans-Martin

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TextMorph behavior
by Marcus Pedersén 18 Jan '11

18 Jan '11

Hi! I have been trying class TextMorph out for making an editable textfield for my GUI. One thing I can't figure out is how to make the text "grow" horisontaly when you write instead of verticaly. I am after the behavior similar to the spotlight search text field in mac. If you write loads of text the oldest text "dissapear" (visualy) on the left hand. I have tried autoFit: false and wrapFlag: false without any desired results. Doesn't TextMorph contain this functionality from start? Do I need to subclass and write the function from scratch? Many thanks in advance! Marcus

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SqF feedback
by stéphane ducasse 21 Jul '07

21 Jul '07

Hi I'm reposting this email since I have the impression that the point was lost in its original thread. ... - Normally after election, politicians do not really listen anymore and I would like to do the inverse. I would really like to know what you expect or would like to see put in place. We have some ideas (bounty system, better process) and I will really listen what the new boarders want to do (I'm even eager to see that :)). We do not have the monopole of good ideas, so if you have some points that you would like to see happening please mention it. Stef

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hash method
by Houssam Fakih 31 Jan '07

31 Jan '07

Hi, When I redefine the = operation for a class I should redefine its hash method. My question is about the definition of the hash method. I read that the method must return a SmallInteger whose value is related to the receiver. I would like to know if there is a general pattern adopted in Squeak for that. I get a look in the Squeak classes but it doesnt help. Thanks, Houssam ____ "Le paradis touche les pieds des mères..." >>> http://csl.ensm-douai.fr/fakih

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RE: Progrmaming in Bytecode?
by Swan, Dean 24 Nov '06

24 Nov '06

>> It's not uncommon to find x86 code padded with a lot of NOPs >> that weren't in the original source. > >Cowardly assembler! ;-) > >> [NOPs...] Sometimes they're there to pad the execution pipeline, and >> sometimes it's just because the code generator allocates a whole large >> enough for the largest form of an instruction to simplify the branch >> target calculations. > >We must be talking about M$oft assemblers here. ;^p) Yes. This has been pretty characteristic of MS assemblers as far back as I can remember (i.e. about MASM 2.0 - I remember being quite excited when MASM 4.0 came out - '186 and '286 code!). >The real problem is that the solution in general might require N >iterations for a piece of code with N branches -- if promoting one of them >from short to long causes the next (or, much more problematically, a >preceding) one to become long too. You're such an optimist. O(n) is close to best case for this problem. >This is a weak form of what I suppose one might call an "oscillating >constraints" problem. (Hands up anyone who has ever seen [La]TeX get Hence, stochastic optimization. Even MS uses stochastic optimizers now, even in vb. (didn't want to say that too loud here. ;) ) >The usual cause for "padding" in (capable) assemblers (other than for >prefetch alignment, as you point out) is due to dynamic linking where the >size of call sites isn't known until link time. (On modern systems the Not only prefetch alignment. I have heard, although I don't know the details that sometimes it's desirable to force a dead cycle in the execution pipeline. I can only guess that this would be to influence the scheduling of the execution units for complex instructions, but I consider myself to be only a "casual observer" with respect to this kind of thing. >In Smalltalk you've also got a bigger problem: for very long methods the >range of even unconditional branches might not be enough, at which point >I know this has nothing whatsoever to do with Smalltalk...) Well, to kind of tie this back into something relevant to Squeak - I know a few people have talked about "new" VM instruction sets. It seems that it might help to think about a VM where all instructions are the same size. This could simplify code generation (i.e. compiling methods), and possibly improve performance and *reduce* code size (at least in the case of long methods). The anticipated performance improvement would come from forcing aligned fetches more often and potentially simpler instruction decoding. It's really nice to work with an architecture where all instructions take up one word of memory, take one cyle to execute, and sometimes can cause five or six different useful things to occur during that one cycle. (ok, so I write a lot of DSP code...) The single cycle thing isn't necessarily relevant for Smalltalk, but those "extended" bytecodes are really distasteful to me. -Dean

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[ANN] Audio Video Library
by Martin Kuball 07 Oct '06

07 Oct '06

Hi I would like to annonce my project to build a Library for processing audio and video material with squeak. I put a 1st version on the SqueakSource at kilana.unibe.ch. It's not much yet. But you can load and analyze avi container with mpeg 4 video and mp2 and mp3 audio content. I did this because I needed a tool to repair some broken avi files. Other tools I tried just failed badly. Try this: RIFFArchive openOn: 'test.avi' "use explore it to get a nice tree view of the chunks in the avi" "open a transcript and execute the following to get some information about the contents" (RIFFArchive openOn: 'test.avi') analyzeVideoStream "To extract the streams inside the avi container do:" (RIFFArchive openOn: 'some.avi') extractAllStreamsToFile: 'base_fileName'. "If you have raw streams you can create an avi this way:" | avi | avi := AVIFile with: (M4VStream on: 'video.m4v') with: (MPAStream on: 'audio.mp3'). avi runtime: 100. avi frameRate: 24000 / 1001. avi createIndex. "not working yet" avi writeTo: (StandardFileStream newFileNamed: 'test.avi') Here is my tentative todo list. - write more documentation and tests - cleanup and speedup - add more container formats like mp4, matroska - add mpeg2 handling (-> dvd authoring???) - connect with the other multimedia bits in squeak (sound, video playing, ...) The project is of course open for everyone to join. Enjoy, Martin

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bugs on mantis: who assigns them ?
by Dan Corneanu 04 Sep '06

04 Sep '06

Hi, how do bugs on mantis get assigned to someone? Who is responsible for this?

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[ANN] A 6 MB SqueakPlugin.image
by Lic. Edgar J. De Cleene 06 Jun '06

06 Jun '06

Here you could see running on Explorer on my Mac. Also run in Firefox, Safari and iCab Now I wish know if someone know how modify the following and someone could use this image remote via Browser <EMBED type="application/x-squeak-source" ALIGN="CENTER" WIDTH="800" HEIGHT="600"> </EMBED> Very thanks !!! Edgar

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Re: Fraction equality and Float infinity problem
by nicolas cellier 12 May '06

12 May '06

Thanks Trygve and Andres, I also agree that comparing float is a bad practice. It is even worse outside squeak because of intel registers extra bits for example (result will depend on use of registry or not and hence on compiler optimization and neighbour code). The question should (2 = 2.0) and (2.0 = 2.0) is interesting... In my opinion, there are cases when float comparison is usefull: precondition to guard against an exception (zero divide or whatever). First solution i was proposing is to continue to answer true to that, since it can be valid as long as no inexact arithmetic took place (depends how we made the 2.0, but the conversion from string is OK). I even happened to use float arithmetic once just to have cheap integer arithmetic on 53bits (OK, shame on me, but it works). Hence we can modify = so as to answer true only in exact arithmetic sense ( (1/2)=0.5 but (1/10)~=0.1 ). Concerning Set and hash code, we can make it working accordingly, using Float asTrueFraction. But there is a performance penalty (factor 100 on hash before optimization). I am not totally opposed to more radical solution you seem suggesting: (2 = 2.0) never answer true. In this case, we can still have efficient hash for comparing (2.0=2.0), and do not have to bother with Integer and Fraction. There are some cases when i would like such a behavior: For example, i want to use compiler to repeatedly evaluate an automatically generated mathematical formula, but i face the too many literals byte code limit. I can reduce number of literals by eliminating double entries, and use a Set for that. Here, i do not want literal #(2.0) being replaced with #(2), and in this case i would prefer 2~=2.0... (Yes, i can have array literals in my formula due to matrix). The only penalty of second solution is to break all bad-practice code... It is always possible to force a conversion toward exact or inexact arithmetic. But people can have programmed with automatic conversion in mind... For example, protect against zero divide with a~=0... (yes a isZero would be better in this case). Is there a lot such code in Squeak ? Hard to say... We must inquire that and ask other squeakers opinion. It is not a thin change... Nicolas Le Mercredi 29 Mars 2006 08:13, Trygve Reenskaug a écrit : > I wholeheartedly agree. We have used tolerance tests for floats since 1962 > because equality tests are meaningless. = for floats should give error. > > Cheers > --Trygve > > At 06:01 29.03.2006, Andres wrote: > >Hello ncellier, > > > >Tuesday, March 28, 2006, 7:25:46 AM, you wrote: > > > >nic> [number hashing is broken] > >nic> What is your opinion ? > > > >IMHO... sometimes it may be convenient to have 2 = 2.0, but since they > >represent different intentions, I would not expect that to happen. > >Why should a perfectly specified integer be equal to, possibly, the > >result of carrying calculations without infinite precision? What > >would it mean if theGreatDoublePrecisionResult = 2? Wouldn't it be > >more interesting (and precise) to ask laysWithin: epsilon from: 2? > > > >In other words, comparing constants makes it look much simpler than > >what it really is. Reading something like anInteger = 2.0 would be, > >from my point of view, highly questionable because it is an assertion > >that an approximation has an *exact* value. Nonsense. > > > > >From a more pragmatic point of view, there is also the issue of 2 = > > > >2.0, but things like > > > > (1 bitShift: 1000) - 1 > > > >cannot be equal to any floating point number supported by common > >hardware. Thus, exploiting anInteger = aFloat is intention obscuring > >by definition since it may or may not work depending on the integer. > >Again, highly questionable. > > > >In short: floating point numbers *may* be equal to integers, but the > >behavior of #= cannot be determined a priori. Since the behavior of > >#= does not imply a relationship of equivalence, the behavior of #hash > >is inconsequential. > > > >Adding integers and floats to a set gets messed up. So we have two > >options... a) don't do it because it is intention obscuring... or b) > >make integers never be equal to floating point numbers. > > > >Same deal with fractions and the like. > > > >-- > >Best regards, > > Andres mailto:sqrmax@optonline.net -------------------------------------------------------

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