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

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

by Sven Van Caekenberghe

> On 6 Oct 2017, at 14:54, horrido <horrido.hobbies(a)gmail.com> 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 >

Oct. 6, 2017

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

by Richard Sargent

"It's Smalltalk. Read the code, Luke."? On Oct 6, 2017 08:55, "horrido" <horrido.hobbies(a)gmail.com> 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? > > Thanks. > > > > -- > Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html > >

Oct. 6, 2017

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

by horrido

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? Thanks. -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Oct. 6, 2017

[Ann] PharoLauncher v1.0.1 released!

by Christophe Demarey

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

ZnClient in Pharo 6.1 not working for Https on Windows

by kmo

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

Oct. 6, 2017

Re: [Pharo-users] SVG Icons

by Sven Van Caekenberghe

That is a very cool example ! Some nit picking (just trying to help make examples/snippets even more sexy). The shortest expression to get to the contents of a URL, using only unary selectors is 'https://s.cdpn.io/3/kiwi.svg' asUrl retrieveContents. XMLDomParser's API also has the option #parseURL: so the following would also work XMLDomParser parseURL: 'https://s.cdpn.io/3/kiwi.svg'. I believe that call actually has some additional functionality too. > On 5 Oct 2017, at 15:24, Peter UhnÃ¡k <i.uhnak(a)gmail.com> wrote: > > Hi, > > this is not really tested, but you can try to do the following > > (installation) > a) install XMLParser from catalog > b) in monticello browser open Pharo/Athens and load latest version of Athens-SVG package > > (usage) > Then you import SVG XML using Converter and paint it on a surface, which you convert to Form. > > ``` > contents := (ZnEasy get: 'https://s.cdpn.io/3/kiwi.svg') contents. > > xmlDoc := XMLDOMParser parse: contents. > > svg := AthensSVGConverter new importXMLDocument: xmlDoc. > svg transform: 'scale(0.5)'. > > extent := 500 @ 500. > > surface := AthensCairoSurface extent: extent. > surface drawDuring: [ :aCanvas | svg renderOn: aCanvas ]. > surface asForm. > ``` > > <image.png> > > Peter > > On Thu, Oct 5, 2017 at 1:50 PM, Steven R. Baker <steven(a)stevenrbaker.com> wrote: > Heya folks! > > I need to load SVG images (for icons) in my application. I've searched > my 6.1 image for SVG, but haven't found anything. > > Is there a library for loading SVGs? I'd really like to get them > directly into instances of Form if possible, but I'm flexible. :) > > Thanks! > > -Steven > > > >

Oct. 6, 2017

Re: [Pharo-users] Creating a new method

by Peter UhnÃ¡k

What I often do is that I write a test and then I just execute the code. When it runs into the non-existent method, the debugger offers a button "create" method. Alternatively I do open a second browser (clicking on "scoped" in the current one or like that (or doubleclicking on a method to get the same method opened in a new browser) Peter On Fri, Oct 6, 2017 at 12:15 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 > >

Oct. 6, 2017

Creating a new method

by Dirk Olmes

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

Oct. 6, 2017

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

by horrido

I've incorporated some of the suggestions. Thanks. Here's a very lively discussion at Hacker News: https://news.ycombinator.com/item?id=15399442 The article has sparked a raging debate. Hacker News readers seem to really like the article, as it has garnered 150 points, /more than any other article that I've ever posted!/ (Even my original TechBeacon article <https://techbeacon.com/how-learning-smalltalk-can-make-you-better-developer> -- which launched my campaign! -- only got 115 points.) You should all participate in the discussion and help to dispel the many misconceptions people have about Pharo/Smalltalk. I find a great deal of ignorance out there, and *only you folks* can address it properly. Thanks. -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Oct. 6, 2017

Re: [Pharo-users] Equals and HashCode Builder

by Stephane Ducasse

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