Squeak-dev December 2007

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129 participants
144 discussions

programatically generating methods
by Niko Matsakis 13 Feb '08

13 Feb '08

What is the best way to programatically generate a CompiledMethod from a string? This is what I currently do: mthd := Compiler new compile:(String streamContents: [:stream | stream nextPutAll: 'bindingsString'; cr; tab; nextPutAll: 'Dynamically generated by bindingsString:' asSmalltalkComment; cr; tab; nextPutAll: '^ '; nextPutAll: aString surroundedBySingleQuotes; nextPut: $.; cr. ]) in:self classified:'bindings' notifying:nil ifFail:[:x | ^ x]. self class addSelector:#bindingsString withMethod: mthd generate. self class organization classify: #bindingsString under:#bindings suppressIfDefault:false. This works, actually, though I'm sure the "ifFail" block is totally wrong. However, it doesn't "feel" like the right way. For one thing, I am not sure that method of Compiler is a public API. For another, I have to repeat a lot of information such as the selector and classification. This is in relation to my last message: I am trying to generate methods that will return constant data so that it survives Monticello. (I also tried hacking around with MCClassDefinition, but that seemed like a lot of work...). The constant data is only a string, so if there is an easier way I'm all ears. thanks! Niko

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Morphic 3 presentation at Smalltalks 2007
by Juan Vuletich 29 Jan '08

29 Jan '08

Hi folks, On Dec 10^th to Dec 12^th we had Smalltalks 2007, the first Smalltalk conference in Buenos Aires, Argentina. There I gave a talk and demo of Morphic 3. You can read more, get the updated Morphic 3 Squeak image, and even see a video of my talk at www.jvuletich.org I hope you like it! Cheers, Juan Vuletich

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Robot VM options
by Robert F. Scheer 13 Jan '08

13 Jan '08

I've tossed the idea of Squeak out to the Portland Area Robotics Society group list and the response is building up (although a bit sluggish). One question that immediately arose was whether Squeak is limited to the "Big 3" OS's or is there a VM for other embedded processors maybe without OS's. The Swiki says Squeak VM's are supported for Mac, MS, RISC and flavors of UNIX. I remember reading somewhere that a student implemented a VM on a native uP as a Summer project. Has there been much VM development on embedded uP's. Is there any work on a Squeak OS on any platform? Thanks for the support! - Robert

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Suspending/resuming processes
by Igor Stasenko 12 Jan '08

12 Jan '08

Hello again, I don't know much detail of Processes but i found one thing which i don't like. A calls to suspend/resume can't be nested e.g. suppose given code: proc suspend < -- suspends process proc suspend < -- does nothing proc resume < -- resumes process proc resume < -- unknown i think it would be better to have a suspend counter, which will indicate, how many times process has received #suspend, and resume it only when when counter goes to zero. This is essentially useful when you need to guarantee that process will stay suspended even if it's currently suspended waiting for semaphore signal. I tried to modify a Launcher , to make it following: 1. just before image save, suspend all processes except current one 2. <save image> 3. if we resuming, run scripts/launch methods using provided command line arguments 4. resume all previously suspended processes. As you see, step 4 is counterpart of step 1. In step 3, i need guarantee, that there is no other processes which can interrupt execution of current process by all means before it will finish execution. But due to fact, that processes can't nest #suspend calls, this leads to resume all processes unconditionally in step 4, regardless that some of them are suspended and waiting for semaphore signal. Please, let's not discuss how i can get around that issue. I'd like to hear arguments for and against adding nesting capabilities of suspend/resume methods. -- Best regards, Igor Stasenko AKA sig.

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Squeak bumper sticker
by Wilkes Joiner 11 Jan '08

11 Jan '08

Next year is a presidential election year in the United States. I thought that Squeak should have its own campaign sticker. Is there a way to get this into the SqueakShop on cafe press? http://wilkesjoiner.com/squeak-08.png

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Process>>terminate woes
by Andreas Raab 08 Jan '08

08 Jan '08

Hi - I had an eventful (which is euphemistic for @!^# up) morning caused by Process>>terminate. In our last round of delay and semaphore discussions I had noticed that there is a possibility of having a race condition in Process>>terminate but dismissed it as being of an application problem (e.g., if you send #terminate make sure you have only one place where you send it). This morning proved conclusively that this is a race condition which can affect *every* user of the system. It is caused by Process>>terminate which says: myList remove: self ifAbsent: []. The reason this is so problematic is that the modification of myList is not atomic and that because of the non-atomic modification there is a possibility of the VM manipulating the very same list concurrently due to an external event (like a network interrupt). When this happens in "just the right way" the effect is that any number of processes at the same priority will "fall off" of the scheduled list. In the image that I was looking at earlier we had the following situation: * ~40 processes were not running * The processes had their myList be an empty linked list * The processes were internally linked (via nextLink) * The processes were all at the same priority Given that most of the processes were unrelated other than having the same priority I think the evidence is pretty clear. The question is now: How can we fix it? My proposal would be to simply change primitiveSuspend such that for a non-active process it will primitively take the process off its suspendingList. This makes suspend a little more general and (by returning the previous suspendingList) it will also guard us against any following cleanup (like the Semaphore situations earlier). Unfortunately, this *will* require VM changes but I don't think it can be helped at this point since the VM will be manipulating these lists atomically anyway. The good news though is that we can have reasonable fallback code which does just exactly what we do today as a fallback to primitiveSuspend. Any comments? Alternatives? Suggestions? Cheers, - Andreas

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Re: [ANN] ICal occurrence API
by Philippe Marschall 05 Jan '08

05 Jan '08

2007/12/31, Alan L. Lovejoy <squeak-dev.sourcery(a)forum-mail.net>: > > Philippe Marschall wrote: > 2007/12/30, Alan L. Lovejoy <architect(a)chronos-st.org>: > > > Jason, > > I spent the the last hour rooting around in the latest version of the > iCalendar package from SqueakSource. I see lots of code for parsing and > representing iCal recurrence rules, > > Yes, for quite some time that was the only thing the package did > because computing the occurrences is a bit tricky. > > > > but can't find any code that > actually attempts to generate the set of occurrences specified by the rules. > > Am I missing something? > > If you load one of the later jbj versions you should get the code > described by Jason, see the added tests in ICEventTests for example > #testOccurencesWithExclusionDate. > > Cheers > Philippe > > > I didn't see any "jbj" versions yesterday. And today, both the "Versions" > tab and the "Latest" tab report "No matching public versions available". > > ??? Sorry I can not reproduce this. It shows me several jbj versions in non-filtered and filtered [1] mode. In the latest tab I see ICal-jbj.67.mcz. [1] http://img175.imageshack.us/img175/8395/jbjversionsiv6.png Cheers Philippe

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Fireworks
by Alexander Lazarevic' 03 Jan '08

03 Jan '08

Close to/After the beginning of 2008 it might be a good time for an (ugly) but fun hack! ;) The project can be loaded into a 3.9 image. http://www.lazarevic.de/download/squeak/fireworks.002.pr This should also work, but no guaranties... http://squeakland.org/project.jsp?http://www.lazarevic.de/download/squeak/f… Cheers (in every sense), Alex :D PS: This is the result of some fun hours of hacking, but shouldn't be looked at closely! After all this should be much nicer in kedama! PPS: Use Alt-. to stop it

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Unix VM path encodings
by Andreas Raab 01 Jan '08

01 Jan '08

Hi - Due to a bug reported against Qwaq Forums I needed to look into how the Unix VM encodes file and path names and got terribly confused. My test case was to create a file with an Umlaut("Jürgen") and to see what both Squeak and the Unix shell reports with varying settings of -pathenc and -textenc. I started with the assumption that since the file system I was running this on is UTF-8 the default settings (-textenc MacRoman and -pathenc UTF-8) ought to be correct. However, the result was very surprising. The file name was reported incorrectly both in the file list as well as by the OS - the file list reported "J?" (truncated after the question mark) and the Unix shell reported "J?rgen" but with a "funky ?" (the glyph is hard to describe without a screenshot; it was neither an umlaut nor a regular question mark). Playing with the settings I could not find any combination that resulted in a consistent representation for all the different views - either the Unix shell was off or Squeak's view was off no matter how I set those encodings. Can someone explain to me how I need to set these values to get a consistent view on file names both from Squeak and Unix? Cheers, - Andreas

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GridBag
by Blake 01 Jan '08

01 Jan '08

Hello, All: I note that here: http://wiki.squeak.org/squeak/282 a suggestion was made for a GridBagLayout (a way to fix columns and rows). I don't actually see one in Squeak however. Has anyone done this? Or is there another (good) way to constrain layouts to a fixed number of columns and rows? ===Blake===

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