Squeak-dev September 2004

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150 participants
437 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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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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[BUG] SM2 Burps after loading Breakpoint support or ColorDevTools
by Thomas A Petersen 05 Dec '05

05 Dec '05

Herman, Goran, et. al, I don't think your Jacaranda script is the problem. I tried the same exercise from a clean 3.7 5566 image and loading SM2 Loader first thing. I get the same crash with Breakpoint Support and ColorDevTools. Checking the change sorter shows that things are installed. There appears to be something going on as SM2 finishes things. Goran, Oh Great Sage of SM.... Can you enlihton us? Thanks much, tap P.S. Here's the debug log. Could this be a side effect of the translation stuff?? ----------------------------------------------------- MessageNotUnderstood: Character>>first 1 December 2003 3:22:52 pm VM: Win32 - Squeak3.5 of '11 April 2003' [latest update: #5180] Image: Squeak3.7alpha [latest update: #5566] Character(Object)>>doesNotUnderstand: #first Receiver: $5 Arguments and temporary variables: aMessage: a Message with selector: #first and arguments: #() Receiver's instance variables: value: 53 SMSqueakMap>>installedVersionOf: Receiver: a SMSqueakMap Arguments and temporary variables: aPackage: SMPackage[Breakpoint Support] Receiver's instance variables: packages: a Dictionary(an UUID ('010894c3-0b8a-47fc-8deb-7c08996bfa71')->SMPackage[OSProcessPlugin] an UUID('017b1882-9376-4bf7-b...etc... accounts: a Dictionary(an UUID ('034ab782-a939-de49-976c-b009701b4406')->SMAccount[Todd Blanchard] an UUID ('035d2bda-c301-6049-b...etc... objects: a Dictionary(an UUID ('007e8c1c-02fa-45fc-97be-7ea4d2f67134')->SMCategory: Package group an UUID ('008c9940-4caf-ac49-a...etc... categories: nil dir: 'sm' transactionCounter: 3011 firstTransactionNumber: 2929 daysBacklog: 182 adminPassword: nil installedPackages: a Dictionary(an UUID ('07469ced-289a-4b6f-bd17-27ec567e681a')->'1.25' an UUID ('1200100f-1a95-...etc... installCounter: nil fileCache: a SMFileCache users: nil --- The full stack --- Character(Object)>>doesNotUnderstand: #first -----------------------------------------------------

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About MAC VM
by stéphane ducasse 13 Sep '05

13 Sep '05

hi john I hope your travel back was good. It was good to have you around at ESUG. I wanted to know if this would be possible that when we double click on an image and that there is already one squeak running, we get another one. Because now we are all copying VM around. Stef

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Re: Yahoo!
by Cg 11 Jun '05

11 Jun '05

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ObjectiveCPlugin progress
by Avi Bryant 25 Dec '04

25 Dec '04

A while ago, Alain Fischer announced his new ObjectiveC plugin, allowing Squeak to use Apple's Cocoa and other ObjectiveC libraries. Todd Blanchard and I have since done some further work on it, and it's at the point now where it can begin be used to build Cocoa UIs from within Squeak. As a quick test, I built a native OS X UI for the system browser, which you can see in this screenshot: http://beta4.com/~avi/browser.jpg The code is on SqueakSource: http://kilana.unibe.ch:8888/ObjectiveCBridge/ObjectiveC-avi.70.mcz You can get a prebuilt plugin (for use with Ian's 3.7 VM) here: http://beta4.com/~avi/ObjectiveCPlugin The browser demo can be run with "CCBrowser test". It requires this nib file: http://beta4.com/~avi/CCBrowser.tgz You need to untar that and place it inside Contents/Resources/English.lproj of your VM application bundle. I'm announcing this partly because I've run out of steam on it for now, and am hoping someone else will take it the next step of building UIs for the various Squeak tools (browsers, debuggers, workspaces, inspectors, etc) in Cocoa. A custom NSMorphicView would also be cool, although might be pretty tricky. Anyway, if someone does try to take this on, I'll be more than happy to answer any questions they have about the underlying bridge code. Cheers, Avi

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Refactoring Associations
by Andrew P. Black 08 Dec '04

08 Dec '04

I've been engaged (in my spare time) for about a year in refactoring associations so that they and their subclasses work a bit more rationally. And I almost have a change set that works! The tricky bit was to get a change set that files in. This I now have, but it took a lot of hand work, because there are various checks to make sure that Association is NOT recompiled. OK, so it files in. And most things seem to work. But the WeakIdentityKeyDictionary "ObsoleteSubclasses" (a class variable of Behavior) is messed up after the file in. It should, I think, hold a mapping between "Association" (that is, the class) and an array of its now obsolete subclasses #(WeakKeyAssocation). It actually holds a mapping between a weak "#(Association)" and that array. Very strange. I think that it's my fault. WeakKeyAssociations used to be implemented by putting a weak one-element array in the key slot of an association. With my refactoring, they are now implemented by using the weak slot of a new subclass, HalfWeakAssociation, for the key and the strong slot for the value, which means that the relative positions of the slots have been switched. Now, here is my question. Does something in the VM or the GC know about WeakKeyAssociations? That is, does something (think) that it knows about this hidden one-element array. Is that how the one element array is appearing in ObsoleteSubclasses? I've done the obvious stuff: the only value that Behavior uses as a key in ObsoleteSubclasses is "self". If it is not something in the VM or GC magic, I can't see where this broken key is coming from. I'm attaching my changeset, and my tests for Association. (This requires the dictionary = fix that I just mailed out.) Inspect ObsoleteSubclasses before and after you file AssociationRefact.Hand in. Andrew

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[FIX][KCP] KCP-0112-FixCanUnderstand
by n.schaerli＠gmx.net 06 Dec '04

06 Dec '04

from preamble: "Change Set: KCP-0112-FixCanUnderstand Date: 12 December 2003 Author: Nathanael Schaerli Fixes canUnderstand so that it deals with abstract methods (i.e., subclassResponsibility and shouldNotImplement) in the right way."!

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[BUG] printShowingDecimalPlaces:
by Pavel Krivanek 26 Nov '04

26 Nov '04

111.2 printShowingDecimalPlaces: 2 -> '111.20' 111111111111111 printShowingDecimalPlaces: 2 -> '1.11' 123e20 printShowingDecimalPlaces: 2 -> '1.23' 10 printShowingDecimalPlaces: 20 -> Error: subscript is out of bounds: 21 Pavel

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