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[Pharo-project] WhatsUp from: 2013-04-15 until: 2013-04-30

by seaside＠rmod.lille.inria.fr

Hi! We're sending this automatic email twice a month, to give the community an opportunity to easily know what's happening and to coordinate efforts. Just answer informally, and feel free to spawn discussions thereafter! ### Here's what I've been up to since the last WhatsUp: - $HEROIC_ACHIEVEMENTS_OR_DISMAL_FAILURES_OR_SIMPLE_BORING_NECESSARY_TASKS ### What's next, until 2013-04-30 (*): - $NEXT_STEPS_TOWARDS_WORLD_DOMINATION (*) we'll be expecting results by then ;)

April 15, 2013

Re: [Pharo-project] On cleaning image startup list

by Igor Stasenko

Here's another measurement.. how often DateAndTime now drifts from system time. (put this method on DateAndTime class side) calculateDrift | durationSinceEpoch systemSeconds milSince secDrifted systemSecondsSinceMidnight | "those two must be close to minimize time distance between measurement" systemSeconds := Time primSecondsClock. " uncomment to see that drift calculation is correct (Delay forSeconds: 5) wait. " milSince := self milliSecondsSinceMidnight. secDrifted := milSince // 1000. durationSinceEpoch := Duration days: SqueakEpoch hours: 0 minutes: 0 seconds: systemSeconds. systemSecondsSinceMidnight := durationSinceEpoch - (durationSinceEpoch days days). ^(Duration seconds: secDrifted) - systemSecondsSinceMidnight ============ Now the experiment, we run this stuff in a tight loop and see how many times the drift (expressed in seconds is non-zero): | count | count := 0. 1 to: 1000000 do: [:i | DateAndTime calculateDrift isZero ifFalse: [ count := count +1 ] ]. count / 1000000 asFloat 0.00142 So, "statistically" every ~1000'th request. "DateAndTime now" is wrong by 1 second than system time.. -- Best regards, Igor Stasenko.

April 15, 2013

Re: [Pharo-project] On cleaning image startup list

by Igor Stasenko

On 15 April 2013 00:31, Norbert Hartl <norbert(a)hartl.name> wrote: > > > Am 14.04.2013 um 21:27 schrieb Igor Stasenko <siguctua(a)gmail.com>: > >> pfff... >> >> DateAndTime class>>initialize >> >> super initialize. >> >> NEVER EVER call super initialize for class initializers! >> >> I think we should add a lint rule for that. >> > Can you explain why? because if you would strictly follow that rule, then you should end up in Behavior>>initialize and your class will be reset completely: initialize "moved here from the class side's #new" super initialize. superclass := Object. "no longer sending any messages, some of them crash the VM" methodDict := self emptyMethodDictionary. format := Object format subclasses sharing all class vars declared in supeclasses. resetting them every time you creating/initializing a subclass is just waste. It only makes sense when your superclass having own class inst var to initialize. But in most cases you want to initialize them differently than in superclass (e.g. superclass ivar of your superclass should be not same as your class). > > Norbert > -- Best regards, Igor Stasenko.

April 14, 2013

Re: [Pharo-project] On cleaning image startup list

by Norbert Hartl

Am 14.04.2013 um 21:27 schrieb Igor Stasenko <siguctua(a)gmail.com>: > pfff... > > DateAndTime class>>initialize > > super initialize. > > NEVER EVER call super initialize for class initializers! > > I think we should add a lint rule for that. > Can you explain why? Norbert

April 14, 2013

[Pharo-project] Videos: MongoDB

by Stephan Eggermont

Taming MongoDB from Pharo https://www.youtube.com/watch?v=LOFygLIRLY8 now uploading: Pharo from the CommandLine

April 14, 2013

Re: [Pharo-project] Videos: FileSystem-Git

by Max Leske

Not a problem. Thanks! On 14.04.2013, at 16:11, Stephan Eggermont <stephan(a)stack.nl> wrote: > Max wrote: >> I noticed that there's a transition in the middle of the video (rotating cube) and then >> the entire video is shown again. So the video contains the same sequence twice. >> What's the idea behind that? > > I'm sorry about that. No CI and lack of tests I'm afraid. > It looked to me like all rendering was done before the machine ran out of disk space > so I thought it safe to start uploading everything asap. I'll put out a fixed version. > > Stephan > > >

April 14, 2013

Re: [Pharo-project] On cleaning image startup list

by phil＠highoctane.be

I was wondering about that method the other day... Now, you made it clear: crap! 2013/4/14 Igor Stasenko <siguctua(a)gmail.com> > the more i learn about DateAndTime the more i lean towards completely > rewriting this ... err.. > crap. (yes. sorry for harsh word). > > DateAndTime class>>now > is not thread-safe.. > > now > | nanoTicks msm | > > nanoTicks := (msm := self milliSecondsSinceMidnight) * 1000000. > > (LastTick < nanoTicks) ifTrue: [ > LastTick := nanoTicks. > ^ self todayAtMilliSeconds: msm]. > > LastTickSemaphore critical: [ > LastTick := LastTick + 1. > ^ self todayAtNanoSeconds: LastTick] > > Wrapping only single assignment to variable with critical section > while leaving another without it > is same as if not using critical section at all. > > > -- > Best regards, > Igor Stasenko. > >

April 14, 2013

Re: [Pharo-project] On cleaning image startup list

by Igor Stasenko

the more i learn about DateAndTime the more i lean towards completely rewriting this ... err.. crap. (yes. sorry for harsh word). DateAndTime class>>now is not thread-safe.. now | nanoTicks msm | nanoTicks := (msm := self milliSecondsSinceMidnight) * 1000000. (LastTick < nanoTicks) ifTrue: [ LastTick := nanoTicks. ^ self todayAtMilliSeconds: msm]. LastTickSemaphore critical: [ LastTick := LastTick + 1. ^ self todayAtNanoSeconds: LastTick] Wrapping only single assignment to variable with critical section while leaving another without it is same as if not using critical section at all. -- Best regards, Igor Stasenko.

April 14, 2013

Re: [Pharo-project] On cleaning image startup list

by Igor Stasenko

On 14 April 2013 21:27, Igor Stasenko <siguctua(a)gmail.com> wrote: > pfff... > > DateAndTime class>>initialize > > super initialize. > > NEVER EVER call super initialize for class initializers! > > I think we should add a lint rule for that. > (https://pharo.fogbugz.com/default.asp?10288) > > -- > Best regards, > Igor Stasenko. -- Best regards, Igor Stasenko.

April 14, 2013

Re: [Pharo-project] On cleaning image startup list

by Igor Stasenko

pfff... DateAndTime class>>initialize super initialize. NEVER EVER call super initialize for class initializers! I think we should add a lint rule for that. -- Best regards, Igor Stasenko.

April 14, 2013