April 2015 - Pharo-users - lists.pharo.org

Re: [Pharo-users] class initialization and class-side variables

by Jan BlizniÄenko

Replying to myself... Here is example package with tests of behavior I expect: http://www.mediafire.com/download/bjmt7p20ndcgddf/Something-bliznjan.6.mcz Only way to aquire it seems to create initialize method in every subclass class, and write just "super initialize" there, but for about 30 subclasses (and many more in the future), it does not seem like fine solution. Jan Jan BlizniÄenko wrote > Thank you both for reply. Unfortunately, it seems I didn't describe my > goal well. > > I want both (all) classes to have separate variables, not shared among > subclasses, but still initialized on class side, not instance side. So I > want those variables to be class-side variables, my problem is with their > initialization. I have a tree of classes, top class (superclass of the > rest) should have class-side variable initialized as empty collection, and > almost all it's subclasses to have, by default, also an empty colletion. > But there will be few classes in this tree, whose collections should > contain something. > > So to return to my previous example... I want SomeClass class-side > variable "SomeCollection" to contain OrderedCollection()... SubClass along > with many more subclasses to also contain OrderedCollection... but also to > have a SpecificSubClass, whose class-side variable "SomeCollection" will > contain OrderedCollection(something, somethingElse...). > > Jan > Sean P. DeNigris wrote >> What you created is a class-side instance variable, which is private to >> just that class. What you want is a class variable, which is shared by >> all subclasses and instances. You declare it in the class definition with >> #classVariableNames:. There is a very nice explanation of these basic >> (but confusing!) concepts in the "Pharo By Example" book. > > Andrei Chis wrote >> Hi, >> >> SomeClass and SubClass are two different objects. >> Based on your setup, if you do not call any initialize method, initially >> calling both "SomeClass isOk" and "SubClass isOk" should return nil. >> >> Running "SomeClass initialize" initializes only the SomeClass object. So >> now "SomeClass isOk" returns true and "SubClass isOk" returns nil, as >> its >> another object that has not been initialized. >> You get the same behaviour if you first call "SubClass initialize". >> Now "SomeClass >> isOk" returns nil because you did not initialize the SomeClass object, >> but >> the SubClass. >> >> Even if you add initialize in the SubClass class and call it first >> "SomeClass >> isOk" will still return false. >> SomeClass and SubClass are just two different objects of types SomeClass >> class and SubClass class. It's the same behaviour that you get when you >> create two instances of these classes. Just because you create an >> instance >> of the type SubClass and call super initialize, >> it doesn't mean that another instance of SomeClass will be initialized. >> >> Hope this makes sense/answers your question. >> >> Cheers, >> Andrei -- View this message in context: http://forum.world.st/class-initialization-and-class-side-variables-tp48228… Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

April 29, 2015

Re: [Pharo-users] class initialization and class-side variables

by Andrei Chis

Aha, now I understand your question. >From what I remember #initialize might only be send to classes if they contain an explicit initialize method, but I might remember wrongly. Cheers, Andrei On Wed, Apr 29, 2015 at 3:08 PM, Jan BlizniÄenko <bliznjan(a)fit.cvut.cz> wrote: > Thank you both for reply. Unfortunately, it seems I didn't describe my goal > well. > > I want both (all) classes to have separate variables, not shared among > subclasses, but still initialized on class side, not instance side. So I > want those variables to be class-side variables, my problem is with their > initialization. I have a tree of classes, top class (superclass of the > rest) > should have class-side variable initialized as empty collection, and almost > all it's subclasses to have, by default, also an empty colletion. But there > will be few classes in this tree, whose collections should contain > something. > > So to return to my previous example... I want SomeClass class-side variable > "SomeCollection" to contain OrderedCollection()... SubClass along with many > more subclasses to also contain OrderedCollection... but also to have a > SpecificSubClass, whose class-side variable "SomeCollection" will contain > OrderedCollection(something, somethingElse...). > > Jan > > > Sean P. DeNigris wrote > > What you created is a class-side instance variable, which is private to > > just that class. What you want is a class variable, which is shared by > all > > subclasses and instances. You declare it in the class definition with > > #classVariableNames:. There is a very nice explanation of these basic > (but > > confusing!) concepts in the "Pharo By Example" book. > > > Andrei Chis wrote > > Hi, > > > > SomeClass and SubClass are two different objects. > > Based on your setup, if you do not call any initialize method, initially > > calling both "SomeClass isOk" and "SubClass isOk" should return nil. > > > > Running "SomeClass initialize" initializes only the SomeClass object. So > > now "SomeClass isOk" returns true and "SubClass isOk" returns nil, as > its > > another object that has not been initialized. > > You get the same behaviour if you first call "SubClass initialize". > > Now "SomeClass > > isOk" returns nil because you did not initialize the SomeClass object, > > but > > the SubClass. > > > > Even if you add initialize in the SubClass class and call it first > > "SomeClass > > isOk" will still return false. > > SomeClass and SubClass are just two different objects of types SomeClass > > class and SubClass class. It's the same behaviour that you get when you > > create two instances of these classes. Just because you create an > instance > > of the type SubClass and call super initialize, > > it doesn't mean that another instance of SomeClass will be initialized. > > > > Hope this makes sense/answers your question. > > > > Cheers, > > Andrei > > > > > > -- > View this message in context: > http://forum.world.st/class-initialization-and-class-side-variables-tp48228… > Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com. > >

April 29, 2015

Re: [Pharo-users] Understanding Slices

by Ben Coman

Someone correct me - any package can have a dependent package added. We just don't do that (I've never seen it my past couple of years with Pharo). A Slice is simply an empty package that has dependencies. Now it seems somewhat tied to development of the Pharo image since it requires an issue number - but I guess you could use it for other purposes with any random issue number or 00000. cheers -ben On Wed, Apr 29, 2015 at 8:18 PM, Sean P. DeNigris <sean(a)clipperadams.com> wrote: > Sergio Fedi wrote > > Are Slices a way to represent a change accross packages? > > Exactly. In the MC browser, there is a button to create a slice from an > issue number. During that workflow, you will be asked to select all > relevant > packages. When the slice is committed or loaded, it will bring all of those > packages with it. > > > > ----- > Cheers, > Sean > -- > View this message in context: > http://forum.world.st/Understanding-Slices-tp4822860p4822867.html > Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com. > >

April 29, 2015

Re: [Pharo-users] class initialization and class-side variables

by Jan BlizniÄenko

Thank you both for reply. Unfortunately, it seems I didn't describe my goal well. I want both (all) classes to have separate variables, not shared among subclasses, but still initialized on class side, not instance side. So I want those variables to be class-side variables, my problem is with their initialization. I have a tree of classes, top class (superclass of the rest) should have class-side variable initialized as empty collection, and almost all it's subclasses to have, by default, also an empty colletion. But there will be few classes in this tree, whose collections should contain something. So to return to my previous example... I want SomeClass class-side variable "SomeCollection" to contain OrderedCollection()... SubClass along with many more subclasses to also contain OrderedCollection... but also to have a SpecificSubClass, whose class-side variable "SomeCollection" will contain OrderedCollection(something, somethingElse...). Jan Sean P. DeNigris wrote > What you created is a class-side instance variable, which is private to > just that class. What you want is a class variable, which is shared by all > subclasses and instances. You declare it in the class definition with > #classVariableNames:. There is a very nice explanation of these basic (but > confusing!) concepts in the "Pharo By Example" book. Andrei Chis wrote > Hi, > > SomeClass and SubClass are two different objects. > Based on your setup, if you do not call any initialize method, initially > calling both "SomeClass isOk" and "SubClass isOk" should return nil. > > Running "SomeClass initialize" initializes only the SomeClass object. So > now "SomeClass isOk" returns true and "SubClass isOk" returns nil, as its > another object that has not been initialized. > You get the same behaviour if you first call "SubClass initialize". > Now "SomeClass > isOk" returns nil because you did not initialize the SomeClass object, > but > the SubClass. > > Even if you add initialize in the SubClass class and call it first > "SomeClass > isOk" will still return false. > SomeClass and SubClass are just two different objects of types SomeClass > class and SubClass class. It's the same behaviour that you get when you > create two instances of these classes. Just because you create an instance > of the type SubClass and call super initialize, > it doesn't mean that another instance of SomeClass will be initialized. > > Hope this makes sense/answers your question. > > Cheers, > Andrei -- View this message in context: http://forum.world.st/class-initialization-and-class-side-variables-tp48228… Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

April 29, 2015

Re: [Pharo-users] class initialization and class-side variables

by Andrei Chis

Hi, SomeClass and SubClass are two different objects. Based on your setup, if you do not call any initialize method, initially calling both "SomeClass isOk" and "SubClass isOk" should return nil. Running "SomeClass initialize" initializes only the SomeClass object. So now "SomeClass isOk" returns true and "SubClass isOk" returns nil, as its another object that has not been initialized. You get the same behaviour if you first call "SubClass initialize". Now "SomeClass isOk" returns nil because you did not initialize the SomeClass object, but the SubClass. Even if you add initialize in the SubClass class and call it first "SomeClass isOk" will still return false. SomeClass and SubClass are just two different objects of types SomeClass class and SubClass class. It's the same behaviour that you get when you create two instances of these classes. Just because you create an instance of the type SubClass and call super initialize, it doesn't mean that another instance of SomeClass will be initialized. Hope this makes sense/answers your question. Cheers, Andrei On Wed, Apr 29, 2015 at 2:25 PM, Jan BlizniÄenko <bliznjan(a)fit.cvut.cz> wrote: > Hello > > It seems I misunderstood some concept of classes in Pharo. My problem is > following: > Let's say I have class named SomeClass (subclass of Object) and class named > SubClass (subclass of SomeClass). > > If I create instance variable on SomeClass and SomeClass>>#initialize which > initializes the variable, it gets initialized also when SubClass instance > is > created. > > Now I'm trying to do something similar for class-side variables, but with > no > success. > If I create class-side variable on SomeClass and SomeClass > class>>#initialize which initializes the variable, it gets initialized only > in SomeClass class, but not in SubClass class. > > What I mean: > > Object subclass: #SomeClass > > SomeClass class > instanceVariableNames: 'Ok' > > SomeClass class>>#initialize > super initialize. > Ok := true > > SomeClass class>>#isOk > ^ Ok > > SomeClass subclass: #SubClass > > calling "SomeClass isOk" returns true. > calling "SubClass isOk" returns nil. > > > now If I create method > > SubClass class>>#initialize > super initialize. > > SubClass initializes as I would expect from my experience with instance > initialization, so "SubClass isOk" now returns true. > > > I will appreciate any help. > > Jan > > > > -- > View this message in context: > http://forum.world.st/class-initialization-and-class-side-variables-tp48228… > Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com. > >

April 29, 2015

Pharo and Hadoop

by phil＠highoctane.be

I am involved in some Hadoop deployments and there is a very interesting possiblity for Pharo in that ecosystem. Namely, there is a YARN thing in there which is a scheduler for distributing computing on a cluster of nodes. It is possible to deploy all kinds of technologies on the nodes (e.g. Python, R, Java) and Pharo images and VM (in headless mode) could be deployed as well. The deployed node can communicate back to what is called an AppllicationManager via REST callbacks (easy game in Pharo). There is also a C API (now, this is FFI or a plugin - http://zookeeper.apache.org/doc/trunk/zookeeperProgrammers.html) There is also an Hadoop component named ZooKeeper that focuses on acting as a distributed configuration repository. One can talk to it with REST too ( https://github.com/apache/zookeeper/tree/trunk/src/contrib/rest) Given the fact that we also can use some Java calls (using the JNI module with 32-bits Java), we can integrate well enough on YARN I'd say. There is also another project which is very nice and this is SLIDER (on YARN). This is about deploying stuff in an elastic way, (see http://slider.incubator.apache.org/) The next logical thing is to have docker containers (containing a pharo stack) deployed dynamically on the cluster using Slider (like this: http://www.slideshare.net/hortonworks/docker-on-slider-45493303) First step here would be to have a basic YARN-Pharo application and a PoC for talking to ZooKeeper. This would open interesting gates for Pharo given its strengths. Even more when we'll get a 64-bit VM. What is cool with Pharo is that an image can be very small and self containing vs Java application (which have tons of Jar files attached). Access to the data on the HDFS thing can happen through NFSv3 so, we can go that route. There is also a REST API to it ( https://hadoop.apache.org/docs/r1.0.4/webhdfs.html) Tell me what you think! Phil

April 29, 2015

Re: [Pharo-users] moving to git and preserving monticello history

by Thierry Goubier

Le 29/04/2015 14:32, Damien Pollet a Ã©crit : > On 20 February 2015 at 11:31, Thierry Goubier <thierry.goubier(a)gmail.com > <mailto:thierry.goubier@gmail.com>> wrote: > > Good point. Bad programmers do commits without messages :):) > > > That could be easily remedied by integrating MC with > http://whatthecommit.com :D Got 'made it compile' on the first try. Yep, that would be allways true ;) Thierry

April 29, 2015

Re: [Pharo-users] class initialization and class-side variables

by Sean P. DeNigris

Jan BlizniÄenko wrote > Now I'm trying to do something similar for class-side variables, but with > no success. What you created is a class-side instance variable, which is private to just that class. What you want is a class variable, which is shared by all subclasses and instances. You declare it in the class definition with #classVariableNames:. There is a very nice explanation of these basic (but confusing!) concepts in the "Pharo By Example" book. ----- Cheers, Sean -- View this message in context: http://forum.world.st/class-initialization-and-class-side-variables-tp48228… Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

April 29, 2015

Re: [Pharo-users] moving to git and preserving monticello history

by Damien Pollet

On 20 February 2015 at 11:31, Thierry Goubier <thierry.goubier(a)gmail.com> wrote: > Good point. Bad programmers do commits without messages :):) > That could be easily remedied by integrating MC with http://whatthecommit.com :D

April 29, 2015

class initialization and class-side variables

by Jan BlizniÄenko

Hello It seems I misunderstood some concept of classes in Pharo. My problem is following: Let's say I have class named SomeClass (subclass of Object) and class named SubClass (subclass of SomeClass). If I create instance variable on SomeClass and SomeClass>>#initialize which initializes the variable, it gets initialized also when SubClass instance is created. Now I'm trying to do something similar for class-side variables, but with no success. If I create class-side variable on SomeClass and SomeClass class>>#initialize which initializes the variable, it gets initialized only in SomeClass class, but not in SubClass class. What I mean: Object subclass: #SomeClass SomeClass class instanceVariableNames: 'Ok' SomeClass class>>#initialize super initialize. Ok := true SomeClass class>>#isOk ^ Ok SomeClass subclass: #SubClass calling "SomeClass isOk" returns true. calling "SubClass isOk" returns nil. now If I create method SubClass class>>#initialize super initialize. SubClass initializes as I would expect from my experience with instance initialization, so "SubClass isOk" now returns true. I will appreciate any help. Jan -- View this message in context: http://forum.world.st/class-initialization-and-class-side-variables-tp48228… Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

April 29, 2015