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[Pharo-project] About announcements
by Igor Stasenko Jan. 3, 2012

Jan. 3, 2012

On 2 January 2012 10:42, Lukas Renggli <renggli(a)gmail.com> wrote: >>>> To you, the current Pharo image is the Pharo Core and you are unhappy that it is too big (for example because RB is there). >>> >>> The size is the least problem. >>> >>> More annoying is that the code quickly gets out of sync and >>> non-changes are added to the history. Both of these problems are >>> already visible today. >>> >>> Additionally, over time people will change/add/remove features that >>> get integrated without proper review. I just had a look at the >>> announcement framework in Pharo 1.4 today, it is unbelievable how a >>> tiny framework could degrade to a bloated, untested and dead slow pile >>> of mud in just a few years :-( >> >> I think your are unfair here. The new features might be untested (current coverage is at 56%), but the changes were meant to provide working weak announcements. And they do work. > > Nice argument for your students reading this thread: > http://memegenerator.net/instance/12779750. > >> But, what do you mean by slow? How did you benchmark it? > > No, but if you look at the code you will see many extra steps: > > 1. It tests if a registry is there: Why would that be necessary in an > object-oriented implementation? > this should be cleaned up. i think it is a leftover from migration code from old Announcer class (pre 1.3) to a new one. We did things incrementally, and had code to migrate all instances from old format to a new one, without losing subscription and without stopping working. > 2. It tests if the registry is empty: Why would that be necessary in > an object-oriented implementation? > not necessary. looks like a optimization. > 3. It enters a critical section of a monitor: This is rarely useful > and the slowest kind of concurrency control available in Pharo (a > Mutex would be enough for what it is used for, and instantiate > multiple semaphores and queues), and btw the lazy initialization of > the monitor is the prime example of a race condition. > agreed here. I would even leave a semaphore. I think it is overlooked by Henrik. It also don't needs a lazy initialization in #protected: , since in #initialize it can just create a ready for use fresh synchronization object. > 4. It creates a copy of the collection of all the subscriptions: This > is rarely useful and wouldn't be necessary if an immutable data > structure was used. > propose better solution how to deal with situation when during handling an announcement, your handler unsubscribing from announcer. > 5. It iterates over all announcements, it doesn't even try to group > announcements of the same kind. > it is pointless to group them, and makes no real difference. Because announcer doesn't knows what kinds of announcements will be announcement, and it knows only about subscriptions. Suppose i have a subscription to Announcement. And i announcing AnnouncementA (a subclass of it). Now it is still have to iterate over inheritance chain in order to determine if given subscription should receive it or not. Of course you can put all subscriptions to Announcement into one group, so you don't need to check it for every subscription: dict at: Announcement put: group. .... so you can do: group do: [:subscription | subscripton deliver: announcement ]. but that imposing that you have a fixed model for announcement relationship, while with #handles: i can simply make it so, that my announcement class are not inherits from its superclass and so, even if you subscribe to Announcement, you won't receive an announcements of my kind, because it simply doesn't walks an inheritance chain in its #handles: method. also, in the end i don't think it matters. Grouping is more optimal (potentially), but you won't see any difference unless you have hundreds of subscriptions, so i think it is not a big deal. Usually there are few subscriptions held by announcer. And so there is simply no need to bother and grouping them. I cannot imagine an announcer holding hundreds or thousands of subscriptions. Announcer allSubInstances collect: [:e | e numberOfSubscriptions ] an OrderedCollection(0 0 1 0) > 6. It wraps each announcement delivery into a curtailed block. It does > that even for those that are never actually announced. > yeah, this can be optimized > 7. It then tests each announcement if it matches, again it doesn't > even try to group the announcements of the same kind. Aside, the match > test was changed so that it doesn't allow instance-based announcements > anymore, breaking some of my code. > what is instance-based announcements? you can use any object as a subscription selector, just make sure it understands #handles: message. i.e. announcer on: myObject do: [ ... ] where myObject can be any object, not just Announcement (sub)class. > 8. It then wraps the actual notification into an exception handler. > Again, this is rarely useful and should probably rather be something > pluggable. > perhaps we can add even more 'bloat' to have 'safe' and 'unsafe' announcers :) But for things like SystemAnnouncer, this is not a question that exception handler must be present and delivery must be guaranteed. > 9. It then culls the announcement and announcer into the block. Not > sure why the announcer is useful, after all the block was registered > with the announcer at some point. > cull there is for passing optional arguments. > So all these 9 steps are not really necessary (or even wanted) in most > case. I doubt that any of them makes the code faster. I am glad that > the code works for you even if all of this new functionality is > untested. And good luck with the race condition :-) > >> There is a point in here. But, as I said, I thought that the point is to produce the core by having jenkins strip away unwanted material. Of course, the other way would be to start from the core as a seed and have jenkins produce the current image. > > Do you really believe that stripping away unwanted material works? No > other open source project in the whole world does it like that, > everybody builds distributions on top of a smaller core: Linux, GCC, > Gnome, FireFox, ... Even in the supermarket, you typically don't get a > vegetable hamper if you just want a some potatoes. > > Lukas > > -- > Lukas Renggli > www.lukas-renggli.ch > -- Best regards, Igor Stasenko.

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[Pharo-project] Bug reports: 1 of 6: Damaged Window/ rectangles on Screen
by S Krish Jan. 3, 2012

Jan. 3, 2012

1. Damaged Window rectangle painting all over.. as you drag the window over the World.. * This is just the repeatable test, but occurs very annoyingly with an image if we have debugged through some piece of Morphic UI code.. Infact this damaged rectangles/ lost refresh of World occurs very frequently with ordinary non forked UI stuff also. of other variants viz: SystemWindow etc.. * Transcript if used on / or STranscript.. the World repaint many a times starts popping up its TextMorph through other top windows.. while it sends the transcript text to it. [ | dialog builder | builder := UITheme exampleBuilder. dialog := builder newPluggableDialogWindow: 'BasicTestDamagedWindows'. dialog contentMorph: (dialog newRow: {dialog newColumn: {dialog newColumn: {dialog newTextEntryFor: (ValueHolder new contents: 'text') getText: #contents setText: #contents: help: 'hostName'}}}); model: self. World openModal: dialog ] fork.

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[Pharo-project] TWM bug when deleting a snapshot
by Sean P. DeNigris Jan. 3, 2012

Jan. 3, 2012

Snapshots are cool! But try this: 1. create two snapshots 2. navigate to the last one 3. delete it Although it is shown removed from the list (i.e. "1/1"), you are not automatically navigated back to the first one. You stay on the deleted one, and when you navigate back to the first with the arrow, the deleted one reappears in the list (i.e. "1/2") Sean -- View this message in context: http://forum.world.st/TWM-bug-when-deleting-a-snapshot-tp4243197p4243197.ht… Sent from the Pharo Smalltalk mailing list archive at Nabble.com.

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[Pharo-project] how to test drag and drop?
by Tudor Girba Jan. 3, 2012

Jan. 3, 2012

Hi (Sean), I would like to test some drag and drop functionality but I do not know how. The BDDExtensions already provides support for simulating clicking, but not drag and drop. Is there an easy way to add this? Cheers, Doru -- www.tudorgirba.com "Reasonable is what we are accustomed with."

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[Pharo-project] [update 1.4] #14277
by stephane ducasse Jan. 2, 2012

Jan. 2, 2012

14277 ----- - Issue 5143: Replacing Monitor with Semaphore in Announcer. Thanks Igor Stasenko and StÃ©phane Ducasse. http://code.google.com/p/pharo/issues/detail?id=5143 - Issue 5140: Some cleanup of unused (but defined) stuff. Thanks Igor Stasenko and StÃ©phane Ducasse. http://code.google.com/p/pharo/issues/detail?id=5140 - Issue 5138: Remove TextConstants from Array. Thanks Igor Stasenko and StÃ©phane Ducasse. http://code.google.com/p/pharo/issues/detail?id=5138 - Issue 5134: Comment of Collection>>#reduce: http://code.google.com/p/pharo/issues/detail?id=5134 - Issue 5098: Settings browser wants to repeatedly safe changes. Thanks Alain Plantec http://code.google.com/p/pharo/issues/detail?id=5098 - Issue 5098: Settings browser wants to repeatedly safe changes. Thanks Alain Plantec http://code.google.com/p/pharo/issues/detail?id=5098 - Issue 5099: Regexp button in settings browser is slow. Thanks Alain Plantec http://code.google.com/p/pharo/issues/detail?id=5099 Stef

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[Pharo-project] Experience with Monitor
by StÃ©phane Ducasse Jan. 2, 2012

Jan. 2, 2012

I remember reading somewhere that Monitor was broken in Pharo/Squeak? I do not remember where. Does anybody have experience with bad monitor behavior? Because we got some bad experience with Monitor. THe funny part is that now doing self inform: freezes to death our image. Stef

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[Pharo-project] [ANN] Aida 6.4 Christmas Edition released
by Janko MivÅ¡ek Jan. 2, 2012

Jan. 2, 2012

Dear Smalltalkers, Well, Christmas is over but to keep with a tradition here is a new Aida 6.4 on Squeak/Pharo and VisualWorks, as a present for Smalltalk community in New Year :) This one is mostly a maintenance release with two new features: * image backup before hourly snapshot * event handling: WebElement #on: anEventSymbol do: aBlock Enhancements: * Widget simplifications and enhancements * form support now works in all possible combinations * Widget examples added to demos More in Release notes: http://www.aidaweb.si/release-notes-6.4 The easiest way to Aida is One-Click Pharo image accessible from: http://www.aidaweb.si/download If you want to load by yourself: on Pharo it is really simple to load, just evaluate this script: Gofer new squeaksource: 'MetacelloRepository'; package: 'ConfigurationOfAida'; load. (Smalltalk at: #ConfigurationOfAida) load. Then simply open http://localhost:8888 . Best regards Janko -- Janko MivÅ¡ek Aida/Web Smalltalk Web Application Server http://www.aidaweb.si

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Re: [Pharo-project] About announcements
by Henrik Sperre Johansen Jan. 2, 2012

Jan. 2, 2012

On 02.01.2012 15:50, Henrik Sperre Johansen wrote: > On 02.01.2012 14:45, Igor Stasenko wrote: >> On 2 January 2012 10:42, Lukas Renggli<renggli(a)gmail.com> wrote: >> >>> 6. It wraps each announcement delivery into a curtailed block. It does >>> that even for those that are never actually announced. >>> >> yeah, this can be optimized > With subs parameter a sequenceable collection, it could be made nearly > non-existant by iterating manually rather than through do:, moving > ifCurtailed to the outer scope. (resuming from index rather than a > copy after failed delivery). > Code would be uglier though. By "nearly non-existant", I meant you pay the overhead once per delivery rather than once per subscriber. It's still an overhead when you have a large number of deliveries to a few subscribers. >> 5. It iterates over all announcements, it doesn't even try to group >> announcements of the same kind. >> > it is pointless to group them, and makes no real difference. Forgot to comment this, I partly agree with both really. Of course it is not pointless to group them, algorithmically speaking. Is the scale at which it matters a usual occurance? Don't think so. Do you fix your announcement lookup by doing so? Yes. Is that necessarily a bad thing? I'm not sure. IIRC, it was one of the discussions Igor "won" (plus, it was simpler to mess about with) :) Cheers, Henry

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[Pharo-project] Image input sensors blocked
by Janko MivÅ¡ek Jan. 2, 2012

Jan. 2, 2012

Hi guys, There is opportunity for someone of you to finally catch this bug! My image is blocked again, but Aida is still working and my backdoor too :) So, I can run any code on image. 'Sensor startUp' didn't help, what can yet try? Last action was OSProcess related, can this be a problem, some sempahore related stuff? Even better, contact me privately to get access to this image via web and debug it by yourself. Best regards Janko -- Janko MivÅ¡ek Aida/Web Smalltalk Web Application Server http://www.aidaweb.si

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[Pharo-project] string hash collisions?
by Philippe Marschall Jan. 2, 2012

Jan. 2, 2012

Hi As you probably noted string hash collisions are all the rage these days [1]. Has anybody looked into whether this applies to Pharo as well? [1] http://events.ccc.de/congress/2011/Fahrplan/events/4680.en.html Cheers Philippe

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