October 2017 - Pharo-users - lists.pharo.org

Re: [Pharo-users] Equals and HashCode Builder

by Stephane Ducasse

Contact noury because I do not remember. But having a little builder is also nice. On Fri, Oct 6, 2017 at 4:15 PM, Vitor Medina Cruz <vitormcruz(a)gmail.com> wrote: > Stephane > > "Vitor why don't you take it as a small project to propose a solution for > Pharo." > > I will try :) I like the idea of using a Trait. > > > Em 6 de out de 2017 05:01, "Stephane Ducasse" <stepharo.self(a)gmail.com> > escreveu: > > Here is what I extracted from older emails > > From David Allouche in Pharo-dev to see if > The ==hash== method is used in Pharo to separate objects in > bucket-based data structures. > > > !! Property > > It must have one required property which is required data integrity: > > !!!! A. > Objects that are equal according to ==\=== must have equal hashes. > > > It should have two desirable properties that are required to support > the algorithmic assumptions of bucket-based data structures: > > !!!! B. > Objects that are not equal should have different hashes. Ideally, the > probability of hash collision should by 1/N where N is the size of > hash value space. > > !!!! C. The hash values should spread as much as possible over their > value space. For example: ProtoObject>>#identityHash. > > > > > How these two desirable properties can be implemented depends on the > actual distribution of the values used to compute the hash. > > An object can safely use XOR hashing if its instance variables are all > different objects that already provide a hash method with these two > properties. > > @@todo check following sentence because the use of singleton is obscure > > For example, an object whose behaviour is defined by several of > singleton delegates of different classes that do not override > Object>>#hash. > > But if the instance variables are not guaranteed to have those > properties, it is necessary to more thoroughly "mix the bits". For > example the method ==hash== of ==SequenceableCollection== illustrates > this point. > > > [[[ > SequenceableCollection >> hash > | hash | > hash := self species hash. > 1 to: self size do: [:i | hash := (hash + (self at: i) hash) hashMultiply]. > ^ hash > ]]] > > > The mixing of the bits is done by the combination of addition and > ==hashMultiply==. The value of ==species hash== does not need to be > processed by ==hashMultiply==, because it is probably computed by the > method =identityHash== of ==ProtoObject==, and that already provides > property C. > > !!! When we should not use XOR > > ==LayoutFrame== is a particularly good example of a data structure > that should not use XOR hashing. Its instance variables provide none > of the required properties: > > - ==SmallInteger>>hash== is just ==^self==. > - In addition, common ==LayoutFrame== instances tend to use pairs of > identical values in their instance variables. Like ==0@0 corner: > 1@1==, or ==Margin fromNumber: 10==. > > A good hash function for LayoutFrame needs to: > > - Get hashes for each instance variable that provides properties A and B. > - Combine them in a way that is order-sensitive (to maintain property > B) and that does some extra mixing (to provide property C). > > Now, we can assume that common values for the instance variables will > be instances of ==SmallInteger==, ==Float==, or ==Fraction==. > > You can see in ==Fraction>>hash==, that a comment mentions the > assumption that the fraction is already reduced, that is what makes it > acceptable to use bitXor. > > The hash of ==SmallInteger== does provide properties A and B, but not > property C. The hash of ==Float== is harder to understand, but tests > show that it provides distinct values for 0.5, 0.25 and 0.125. So it > hopefully provides B for the range of values of interest to > ==LayoutFrame==. > > Another class that has similar hashing constraints to ==LayoutFrame== > is ==Point==. Its ==hash== method is: > > [[[ > Point >> hash > "Hash is reimplemented because = is implemented." > ^(x hash hashMultiply + y hash) hashMultiply > ]]] > > It does not include species in the computation, which is less than > ideal because it favours collisions with objects of different species > that have a similar content and a the same hash algorithm. > > Finally, it is probably not necessary or useful to use the accessors > to get to the instance variables. > > So a good implementation for LayoutFrame is > > [[[ > LayoutFrame >> hash > | hash | > hash := self species hash > hash := (hash + leftFraction hash) hashMultiply > hash := (hash + leftOffset hash) hashMultiply > hash := (hash + topFraction hash) hashMultiply > hash := (hash + topOffset hash) hashMultiply > hash := (hash + rightFraction hash) hashMultiply > hash := (hash + rightOffset hash) hashMultiply > hash := (hash + bottomFraction hash) hashMultiply > hash := (hash + bottomOffset hash) hashMultiply > ^ hash > ]]] > > On Fri, Oct 6, 2017 at 9:59 AM, Stephane Ducasse > <stepharo.self(a)gmail.com> wrote: >> Noury also proposed a trait to avoid to systematically have to implement >> hash. >> Vitor why don't you take it as a small project to propose a solution for >> Pharo. >> >> On Thu, Oct 5, 2017 at 6:34 PM, Vitor Medina Cruz <vitormcruz(a)gmail.com> >> wrote: >>> Yes, canEqual implementation also make #= be commutative. >>> >>> On Tue, Oct 3, 2017 at 11:11 AM, Denis Kudriashov <dionisiydk(a)gmail.com> >>> wrote: >>>> >>>> >>>> 2017-10-02 17:30 GMT+02:00 Denis Kudriashov <dionisiydk(a)gmail.com>: >>>>> >>>>> >>>>> 2017-10-02 17:13 GMT+02:00 Vitor Medina Cruz <vitormcruz(a)gmail.com>: >>>>>> >>>>>> I am sorry, not species, but #isKindOf istead of #= to compare >>>>>> classes. >>>>> >>>>> >>>>> It is bad idea. #= should be transitive. >>>> >>>> >>>> Oh, I used wrong word, shame on me :). I tried to say commutative. >>>> >>>>> >>>>> How you will generate it with isKindOf: logic? You need to know common >>>>> parent. >>>>> >>>>> Also I not remember cases where I was needed two instances of different >>>>> classes to be equal. >>>>> And I can imaging the problems which it will lead to. >>>>> >>>>>> >>>>>> >>>>>> On Mon, Oct 2, 2017 at 11:57 AM, Denis Kudriashov >>>>>> <dionisiydk(a)gmail.com> >>>>>> wrote: >>>>>>> >>>>>>> >>>>>>> 2017-10-02 16:37 GMT+02:00 Sean P. DeNigris <sean(a)clipperadams.com>: >>>>>>>> >>>>>>>> >>>>>>>> Two questions/comments about the generated code: >>>>>>>> 1. #= >>>>>>>> ... >>>>>>>> self class = anObject class "should compare #species >>>>>>>> instead?" >>>>>>>> ifFalse: [ ^ false ]. >>>>>>>> ... >>>>>>>> Typically, I've seen #species instead of #class in the guard >>>>>>>> statement. >>>>>>>> Should we change it to that? >>>>>>> >>>>>>> >>>>>>> I doubt that it is important for domain classes. Because I never saw >>>>>>> the user of #species which is not a kind of Collection. And for >>>>>>> collections >>>>>>> this refactoring is not valid anyway. >>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> 2. #hash >>>>>>>> ^ var1 hash bitXor: (var2 hash bitXor: var3 hash) >>>>>>>> Is this implementation always safe? It's what I usually hand roll >>>>>>>> based on >>>>>>>> what I've seen, but Andres Valloud wrote a whole (large) book on >>>>>>>> hashing, so >>>>>>>> I've always wondered if I was missing somethingâ¦ >>>>>>>> >>>>>>>> >>>>>>>> >>>>>>>> ----- >>>>>>>> Cheers, >>>>>>>> Sean >>>>>>>> -- >>>>>>>> Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html >>>>>>>> >>>>>>> >>>>>> >>>>> >>>> >>> > >

Oct. 6, 2017

Re: [Pharo-users] Behold Pharo: The Modern Smalltalk

by Stephane Ducasse

This is fun because I was thinking that we should add to the main page a videos of the counter coding in the debugger and GTInspector. We have the mooc videos showing ProfStef so we have nearly everything we need and now they are available (should upload them with english voice). Stef On Fri, Oct 6, 2017 at 5:39 PM, Ben Coman <btc(a)openinworld.com> wrote: > I saw this comment, and wonder if we might have an intro video (or cartoon) > of how to run the ProfStef tutorial in the first few minutes of opening your > first image. > >> They need to work on the presentation. How do you get started ? How does >> the code look like ? etc. Not just "download this program and buy this book" > reply > > yes, time, resources, someoneHasToDoIt all apply. > just a random thought, > cheers -ben > > On Fri, Oct 6, 2017 at 9:47 PM, horrido <horrido.hobbies(a)gmail.com> wrote: >> >> Thanks. I gave your answer verbatim. I also added the following paragraph: >> >> The problem I find with todayâs developers is that they are rather >> closed-minded. They are rigid and inflexible, and not willing to adapt to >> new and different ways of doing things. In my generation (circa >> 1980â1990), >> people didnât have a problem with trying different technologies. Thatâs >> why >> I had no issue with learning Smalltalk 10 years ago, after I had retired >> from a 20-year-long career in C systems programming and FORTRAN scientific >> programming. >> >> >> >> Sven Van Caekenberghe-2 wrote >> >> On 6 Oct 2017, at 14:54, horrido < >> >> > horrido.hobbies@ >> >> > > wrote: >> >> >> >> I received this comment from someone who complained: >> >> >> >> *What about the lack of documentation? From time to time Iâve checked >> >> some >> >> SmallTalk implementations like Squeak, GNU-Smalltalk and now Pharo. Of >> >> these, only GNU-SmallTalk appears to have a free, official programming >> >> guide >> >> and core library reference that any serious programmer expects from a >> >> language. >> >> >> >> https://www.gnu.org/software/smalltalk/manual-base/html_node/* >> >> >> >> I pointed to Pharo's documentation but then he came back with: >> >> >> >> *Then show me a link of the free, maintained reference documentation >> >> for >> >> the >> >> classes that form âthe core libraryâ, like this one for Python >> >> (https://docs.python.org/3/library/index.html)* >> >> >> >> It's true, most Smalltalks do not have a core library reference, not >> >> even >> >> VisualWorks! So what is the proper response to this complaint? >> > >> > The first answer is that Pharo/Smalltalk is unique in that a running >> > system/IDE contains _all_ source code, _all_ documentation (class, >> > method, >> > help, tutorial), _all_ unit tests and _all_ runnable examples in a very >> > easy, accessible way. It takes some getting used to, but this is >> > actually >> > better and much more powerful than any alternative. >> > >> > The second answer is that there are lots of books and articles that take >> > the classic/structured book/paper approach. There is >> > http://books.pharo.org, http://themoosebook.org, >> > http://book.seaside.st/book, http://medium.com/concerning-pharo and many >> > more. >> > >> >> Thanks. >> >> >> >> >> >> >> >> -- >> >> Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html >> >> >> >> >> >> >> >> -- >> Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html >> >

Oct. 6, 2017

Re: [Pharo-users] Creating a new method

by Stephane Ducasse

Hi Dirk have a look at - one one coding the counter http://rmod-pharo-mooc.lille.inria.fr/MOOC/Videos/W1/C019-W1S-Videos-Redo-C… (we should have the english versions now) C019-W1-Videos-Redo-CodingCounterInDebugger-FR-V2-HD_720p_4Mbs.m4v you can find the subtitles around the same folder. Stef On Fri, Oct 6, 2017 at 4:16 PM, Ben Coman <btc(a)openinworld.com> wrote: > > > On Fri, Oct 6, 2017 at 6:15 PM, Dirk Olmes <dirk(a)xanthippe.ping.de> wrote: >> >> Hi, >> >> I may be asking an absolute noob question but I was unable to find any >> useful hints on google ... >> >> I often find myself writing methods that do not yet exist when >> implementing other methods, e.g. when I'm writing the implementation of >> methodA I'm calling out to methodB. >> >> What's the easiest way to create the new method? I know I can jump >> aroung through hoops with a separate browser but that feels cumbersome. >> >> I understand that the editor/runtime/whatever cannot know 100% of the >> time where to put the new method but at least for messages to self it >> should be smart enough to offer some kind of help. >> >> -dirk >> > > A common Pharo workflow is known as "programming from within the debugger." > Run your #methodA code as soon as possible, and when the debugger pops up > because someObject hasn't yet implemented #methodB, the debugger helps you > create #methodB in the right place. > > Some examples... > * https://www.youtube.com/watch?v=ymITEeAOtEA > * > http://www.virtuouscode.com/2015/05/11/in-which-i-make-you-hate-ruby-in-7-m… > > Give it a go and stick with it for a while, and you'll understand why > Smalltalk invented Test Driven Development (and it may change they way you > think about programming.) > > cheers -ben

Oct. 6, 2017

Re: [Pharo-users] ZnClient in Pharo 6.1 not working for Https on Windows

by Cyril Ferlicot D.

Le 06/10/2017 Ã 13:02, kmo a Ã©critÂ : > I was trying to Soup on Windows 7 and found I could not access https sites > > On windows 7 and 10 the following code fails: > > ZnEasy get:'https://genius.com/Alice-nuvole-lyrics'. > > This works fine in Pharo 5 on Windows. Also works fine with Pharo 6.1 (32 > bit) on Linux. > > The problem is Pharo 6.1 on Windows. > > The error is: > > "SSL/TLS plugin initialization failed (VM plugin missing ? OS libraries > missing ?)" > > I know that his has been seen on Linux in the past - see > http://forum.world.st/SSL-TLS-plugin-initailization-failed-VM-plugin-missin… > > I'm running the latest vm and 6.1 image. > > > > -- > Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html > I just saw that Windows Defender consider this plugin as a Trojan and delete it. Name of the menace: Trojan:Win32/Azden.A!cl Should this be reported on Pharo's issue tracker or on opensmalltalk one? -- Cyril Ferlicot https://ferlicot.fr http://www.synectique.eu 2 rue Jacques PrÃ©vert 01, 59650 Villeneuve d'ascq France

Oct. 6, 2017

Re: [Pharo-users] Seaside Magritte tutorial

by Stephane Ducasse

Now there is a much better one :) To be announced soooooonnnnn But you can have it as beta reader. https://github.com/SquareBracketAssociates/Booklet-Magritte check the bintray link in the readme Any typos, bugs, errors are welcome Stef On Fri, Oct 6, 2017 at 4:57 PM, Sven Van Caekenberghe <sven(a)stfx.eu> wrote: > > >> On 6 Oct 2017, at 16:54, Vitor Medina Cruz <vitormcruz(a)gmail.com> wrote: >> >> Hello! >> >> Is there any tutorial focused on Seaside and Magritte that creates an example app using Magritte in a job trivial way? >> >> I mean, something that mix or segregate descriptions from some object to generate pages on Seaside, that show a way to personalize more the generated page, if that is possible. >> >> Thanks in advance! > > Did you see > > http://book.seaside.st/book/advanced/magritte > > maybe a bit old, I don't know > >

Oct. 6, 2017

Re: [Pharo-users] [Ann] PharoLauncher v1.0.1 released!

by Stephane Ducasse

Tx Christophe We should add a new page on Pharo.org about the launcher. On Fri, Oct 6, 2017 at 1:26 PM, Christophe Demarey <christophe.demarey(a)inria.fr> wrote: > Hi all, > > I just released a new version of the PharoLauncher 1.0.1. > Here are major improvements since last version: > > Pharo launcher is now distributed with a Pharo 60 image with a 32-bits > threaded VM (to avoid hangs when using OSProcess). > Add a VM management utility able to find (and download) the appropriate VM > for a given image. So, the launcher is NOT shipped anymore with an extra VM. > It will fetch required VM when needed. > Pharo Launcher files (images, VMs) are now considered as user Documents > (easier to find). Consequently, they are now stored in the standard > documents folder, i.e. > > $HOME/Documents/Pharo on OS X, > $HOME/My Documents/Pharo on windows, > $HOME/Pharo on Linux (some linux distributions provide a document folder but > some others not, so we put it in the HOME directory in all cases). > In this folder, you will find your images and virtual machines needed to run > images. > > Use of ProcessWrapper to run images on Windows. > Adds download of sources file for Pharo images > 60. > Left panel is now used for official images and Jenkins jobs templates and > right panel is used for local images. > New mooc entry with the image ready to start the Pharo Mooc. > New deprecated category to find old official Pharo images. > Use system unzip when possible (Pharo unzip does not manage file permissions > nor symbolic links). > > You can get platform bundles from files.pharo.org: > > Os X: http://files.pharo.org/platform/launcher/Pharo_1.0.1.dmg > Windows: http://files.pharo.org/platform/launcher/pharo_installer-1.0.1.exe > Linux: http://files.pharo.org/platform/launcher/Pharo-linux-1.0.1.zip > > > Enjoy, > Christophe. > > For those wanted more info on how the adequate VM is computed, here is the > process: > > determine the image format version > find (and optionnaly fetch) a compatible VM (a VM able to run this image > format) and run the image to get its Pharo version number > find (and optionnaly fetch) the appropriate VM for this specific Pharo image > version. Sources files are also downloaded with the VM when applicable. > run the image with the appropriate VM > >

Oct. 6, 2017

Re: [Pharo-users] Behold Pharo: The Modern Smalltalk

by Ben Coman

I saw this comment, and wonder if we might have an intro video (or cartoon) of how to run the ProfStef tutorial in the first few minutes of opening your first image. > They need to work on the presentation. How do you get started ? How does the code look like ? etc. Not just "download this program and buy this book" reply yes, time, resources, someoneHasToDoIt all apply. just a random thought, cheers -ben On Fri, Oct 6, 2017 at 9:47 PM, horrido <horrido.hobbies(a)gmail.com> wrote: > Thanks. I gave your answer verbatim. I also added the following paragraph: > > The problem I find with todayâs developers is that they are rather > closed-minded. They are rigid and inflexible, and not willing to adapt to > new and different ways of doing things. In my generation (circa 1980â1990), > people didnât have a problem with trying different technologies. Thatâs why > I had no issue with learning Smalltalk 10 years ago, after I had retired > from a 20-year-long career in C systems programming and FORTRAN scientific > programming. > > > > Sven Van Caekenberghe-2 wrote > >> On 6 Oct 2017, at 14:54, horrido < > > > horrido.hobbies@ > > > > wrote: > >> > >> I received this comment from someone who complained: > >> > >> *What about the lack of documentation? From time to time Iâve checked > >> some > >> SmallTalk implementations like Squeak, GNU-Smalltalk and now Pharo. Of > >> these, only GNU-SmallTalk appears to have a free, official programming > >> guide > >> and core library reference that any serious programmer expects from a > >> language. > >> > >> https://www.gnu.org/software/smalltalk/manual-base/html_node/* > >> > >> I pointed to Pharo's documentation but then he came back with: > >> > >> *Then show me a link of the free, maintained reference documentation for > >> the > >> classes that form âthe core libraryâ, like this one for Python > >> (https://docs.python.org/3/library/index.html)* > >> > >> It's true, most Smalltalks do not have a core library reference, not > even > >> VisualWorks! So what is the proper response to this complaint? > > > > The first answer is that Pharo/Smalltalk is unique in that a running > > system/IDE contains _all_ source code, _all_ documentation (class, > method, > > help, tutorial), _all_ unit tests and _all_ runnable examples in a very > > easy, accessible way. It takes some getting used to, but this is actually > > better and much more powerful than any alternative. > > > > The second answer is that there are lots of books and articles that take > > the classic/structured book/paper approach. There is > > http://books.pharo.org, http://themoosebook.org, > > http://book.seaside.st/book, http://medium.com/concerning-pharo and many > > more. > > > >> Thanks. > >> > >> > >> > >> -- > >> Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html > >> > > > > > > -- > Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html > >

Oct. 6, 2017

Re: [Pharo-users] ZnClient in Pharo 6.1 not working for Https on Windows

by kmo

Thanks. I re-extracted SqueakSSL.dll from the zip file and now it works! -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Oct. 6, 2017

Re: [Pharo-users] Update of ConfigurationOfGlorp

by Herby VojÄÃk

Sven Van Caekenberghe wrote: > >> On 4 Oct 2017, at 17:20, stephan<stephan(a)stack.nl> wrote: >> >> I've added a Pharo 7 version, copied the configurations from DBXTalk/Glorp to DBXTalk/Configurations and the metarepos, and >> replaced the #'Pharo6.0.x' style names by #'Pharo6.x' style. >> Please let me know if that creates problems >> >> Stephan > > I tested with the latest ConfigurationOfGlorp-StephanEggermont.61 in Pharo 7 and that seems OK (not super clean, but OK). > > Thx. > > Any chance of incorporating fixes 127 / 129? Herby

Oct. 6, 2017

Re: [Pharo-users] Update of ConfigurationOfGlorp

by Sven Van Caekenberghe

> On 4 Oct 2017, at 17:20, stephan <stephan(a)stack.nl> wrote: > > I've added a Pharo 7 version, copied the configurations from DBXTalk/Glorp to DBXTalk/Configurations and the metarepos, and > replaced the #'Pharo6.0.x' style names by #'Pharo6.x' style. > Please let me know if that creates problems > > Stephan I tested with the latest ConfigurationOfGlorp-StephanEggermont.61 in Pharo 7 and that seems OK (not super clean, but OK). Thx.

Oct. 6, 2017