December 2020 - Pharo-users

Pharo image size increases continuously

by Dario Romano Trussardi

Ciao, I am developing a seaside based application in pharo Pharo 8.0.0 Build information: Pharo-8.0.0+build.1141.sha.1b7a8d8203fce2a57794451f555bba4222614081 (64 Bit) Seaside version 3.4.3 Grease Version 1.6.1 Iceberg 1.6.7 The Pharo image size increases continuously and now we are at: 15213731 Dec 23 13:20 Pharo80041-201223D.changes 280245832 Dec 23 13:20 Pharo80041-201223D.image The system begins to be unstable. Until a few days ago, closing all the System Browser windows and saving the image the system resized itself. But now this trick doesn't work either. Any suggestions on how to solve, manage this question? Thanks, Dario

Dec. 23, 2020

Re: subclassResponsibility

by Richard Sargent

Is there a way force allSubclasses to implement the method? No. Pretty much, you need to avoid subclassing concrete classes. i.e. if A has subclasses B and C, refactor to create an abstract A' and move A to be a leaf subclass of A'. -----Original Message----- From: Jimmie Houchin [mailto:jlhouchin@gmail.com] Sent: December 22, 2020 15:08 To: Any question about pharo is welcome Subject: [Pharo-users] subclassResponsibility Hello, I have created a class which will have many subclasses some of which will have subclasses of their own. I want every single class to implement a class method #shortName which will provide a short string as a human readable short identifier to the object. I have in the highest superClass shortName Â Â Â self subclassResponsibility But the moment I implement it in a subclass which has subclasses. Those subclasses are now using their closest superClasses implementation. Is there a way force allSubclasses to implement the method? Thanks. Jimmie

Dec. 23, 2020

Re: [exercism bowling challenge] Is there a better way to do this

by Richard O'Keefe

Yes, there is a better way to do it. I found this particular problem at the Programming Praxis web site, which took it from http://butunclebob.com/ArticleS.UncleBob.TheBowlingGameKata This is a superb example of how an informal specification and a set of test cases can diverge. The specification says to score a bowling game according to a particular set of rules. Here is exactly the algorithm called for, written in the functional programming language Haskell: score (10:b:c:xs) = b+10+c+(if null xs then 0 else score (b:c:xs)) score (a:b:c:xs) | a+b = 10 = 10+c+(if null xs then 0 else score (c:xs)) score (a:b:xs) = a+b+(if null xs then 0 else score xs) That's *it*. Explanation, (10:b:c:xs) means "a sequence starting with 10, followed by something (call it b), followed by something (call it c), followed by the rest of the sequence (call that xs). This is actually strictly statically typed as well. And it shows the while the data are *provided* from first to last, the score is most easily *computed* from last to first. Let's remind ourselves of Kent Beck's four rules of good code: 1. Runs all the tests 2. Contains no duplication 3. Expresses all the important design intentions 4. Minimizes entities (e.g. classes and methods). Hence the Extreme Programming slogan "You Ain't Gonna Need It." Now we come to the divergence between the specification (which calls for #roll: and #score methods) and the tests (which call for a #scoreAfterRolling: method and then in test 15 calls for #scoreRolling:after:). There are two kind of test case for this exercise. + check that the result is correct in a good case - check that the right error is raised given bad data. Now the second kind go far beyond the informal specification and require not only that certain errors be detected but *when* they are detected. And this is something you have to bear in mind when writing down your test cases: you have to prevent ideas you may have about *how* the code might work creeping into your test cases and forcing the code to work that way. Most of my code, and most of the trouble I had writing the code, was about these "does it report the right error at the right time and oh yeah I made up these 'right' definitions with no warrant in the customer's requirements" test cases. I mean, seriously, NO methods in common between the specifications and tests? Returning to Kent Beck's maxims. How many classes do we need? The test code calls for ONE class, "Bowling". There are no tests for any Frame pr Roll classes, and no need for any. How many methods does it need? The test code checks #scoreAfterRolling and #scoreRolling:after: There are not tests for any others. What state should the instances of the class hold? There is hint You will need to store some game state. but that applies to the #roll:/#score interface, NOT to the interface that's actually tested. Use as many classes and methods as you NEED, but remember that you need a lot fewer than you think, On Mon, 21 Dec 2020 at 23:05, r.wobben--- via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > Hello, > > > To come back at this one. > > I made a class Bowling and a class Frame which contains two instance > variables named firstThrow and secondThrow. > > > but I still wonder how do I know which one to fill in. > > I can do ` (firstThrow nil?) ` but that feels not right. > > > Is there a more idiomatic solution for this ? > > > Roelof > > >

Dec. 23, 2020

subclassResponsibility

by Jimmie Houchin

Hello, I have created a class which will have many subclasses some of which will have subclasses of their own. I want every single class to implement a class method #shortName which will provide a short string as a human readable short identifier to the object. I have in the highest superClass shortName Â Â Â self subclassResponsibility But the moment I implement it in a subclass which has subclasses. Those subclasses are now using their closest superClasses implementation. Is there a way force allSubclasses to implement the method? Thanks. Jimmie

Dec. 22, 2020

Re: How coverage is computed with SmalltalkCI and coverall

by Gabriel Cotelli

Just in case you don't find out, the wrapping is done in *SCICoverageWrapper* in SmalltalkCI-Coverage-Core package. If Pharo provides some native facility to calculate code coverage it should be pretty easy to adapt smalltalkCI to use it (if it will work at the method level). In case the coverage strategy is more focused like branch or statement based it will require a bit of change on smaltalkCI reporting support. On Sun, Dec 20, 2020 at 3:52 PM StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> wrote: > Ok I could not see the MW or methods as object use but now I get it. > So the granularity is already good. > > I would really like the support for coverage in Pharo ecosystem and not > only on build system. > I would really like that we push tests to the next level :). > > S > > On 20 Dec 2020, at 19:08, BenoÃ®t Verhaeghe <badetitou(a)gmail.com> wrote: > > First, configuration looks for classes and packages ( look at > .smalltalk.ston file ) > Second, you take all the methods inside the classes and packages. > If a method is an extension ( for instance, method A of class C is under > package P. But class C is under package P2), then select all the methods of > the class of the method ( this logic is under discussion in two issues of > SmallTalkCI. > > Third, SmallTalkCI wraps each method ( install a wrapper in the method's > class that is called instead of the real method ). > When a wrapper is called, marks a Boolean to true, and calls the original > method. > > Finally, the coverage is the number of covered methods marked as true > compare to the total number of covered method. > > ( Note : the wrapping is not done using reflectivity whereas it can be a > good idea ? ) > > > > Le dim. 20 dÃ©c. 2020 Ã 18:29, StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> > a Ã©crit : > >> Thanks I could not find it. >> I read the code and it is still unclear what is the logic. I could not >> figure out what we get lines here. >> >> I would like to resurrect the AST interpreter to get some information on >> AST level coverage. >> What is see is that so far this is a heuristic that is used in >> SmalltalkCI. >> >> S. >> >> On 20 Dec 2020, at 13:27, Gabriel Cotelli <g.cotelli(a)gmail.com> wrote: >> >> AFAIR is implemented in >> https://github.com/hpi-swa/smalltalkCI/tree/master/repository/SmalltalkCI-P… >> and it's superclass. >> >> On Sun, Dec 20, 2020, 05:44 StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> >> wrote: >> >>> Hi >>> >>> I would like to know exactly how the test coverage is computed. >>> I read all the code of SmalltalkCi and I could not find it. >>> >>> S. >>> -------------------------------------------- >>> StÃ©phane Ducasse >>> http://stephane.ducasse.free.fr / http://www.pharo.org >>> 03 59 35 87 52 >>> Assistant: Aurore Dalle >>> FAX 03 59 57 78 50 >>> TEL 03 59 35 86 16 >>> S. Ducasse - Inria >>> 40, avenue Halley, >>> Parc Scientifique de la Haute Borne, BÃ¢t.A, Park Plaza >>> Villeneuve d'Ascq 59650 >>> France >>> >>> >> -------------------------------------------- >> StÃ©phane Ducasse >> http://stephane.ducasse.free.fr / http://www.pharo.org >> 03 59 35 87 52 >> Assistant: Aurore Dalle >> FAX 03 59 57 78 50 >> TEL 03 59 35 86 16 >> S. Ducasse - Inria >> 40, avenue Halley, >> Parc Scientifique de la Haute Borne, BÃ¢t.A, Park Plaza >> Villeneuve d'Ascq 59650 >> France >> >> > -------------------------------------------- > StÃ©phane Ducasse > http://stephane.ducasse.free.fr / http://www.pharo.org > 03 59 35 87 52 > Assistant: Aurore Dalle > FAX 03 59 57 78 50 > TEL 03 59 35 86 16 > S. Ducasse - Inria > 40, avenue Halley, > Parc Scientifique de la Haute Borne, BÃ¢t.A, Park Plaza > Villeneuve d'Ascq 59650 > France > >

Dec. 21, 2020

Re: [exercism bowling challenge] Is there a better way to do this

by Roelof Wobben

Op 21-12-2020 om 13:56 schreef Russ Whaley: > I had a lot of fun putting my bowling game together back when you > first brought this up. > > I have a Bowling (Game) class, a Frame class, aThrow class and a > Score(ing) class.Â I made the Throws a class that I put in an > OrderedCollection - but instVars would work as well... the rest of > your game should be oblivious to your 'underpinnings' anyway. > > The Bowling class controls the game and cycles through 10 frames, > which I create then house in an OrderedCollection at the start of the > game.Â Frame has a subclass called Frame10 that is instantiated for > the 10th frame of the game. > > Bowling processes each Frame, starting at 1, from the collection, and > does a runFrame (or whatever action name you want).Â A Frame consists > of throws, 1, 2, or 3 - depending on the frame and the result of the > first throw. > That is also the way I can work. But I do not see how I can convert the given collection to frames Roelof

Dec. 21, 2020

Re: [exercism bowling challenge] Is there a better way to do this

by Russ Whaley

I had a lot of fun putting my bowling game together back when you first brought this up. I have a Bowling (Game) class, a Frame class, aThrow class and a Score(ing) class. I made the Throws a class that I put in an OrderedCollection - but instVars would work as well... the rest of your game should be oblivious to your 'underpinnings' anyway. The Bowling class controls the game and cycles through 10 frames, which I create then house in an OrderedCollection at the start of the game. Frame has a subclass called Frame10 that is instantiated for the 10th frame of the game. Bowling processes each Frame, starting at 1, from the collection, and does a runFrame (or whatever action name you want). A Frame consists of throws, 1, 2, or 3 - depending on the frame and the result of the first throw. A throw returns a random number of 'knocked down pins' between 0 (gutter ball) and the number of pins remaining in the frame (results of a previous throw). So my Frame always knows -pinsCleared and -pinsRemaining - but it asks the Throws what they cleared to calculate that info. After each throw, the Score class runs through the frames to see if anything additional can be scored... - i.e. the first throw on frame3 would be added to the 'spare' of frame2 plus the score of frame 1 - to get the frame 2 score. But frame3 cannot yet be scored. Then when the frame does the 2nd throw, (as long as it's not a spare), the 3rd frame can also be scored. Scoring was certainly the most challenging/fun part for me as there are a number of variables to consider. Scoring would start at frame1 each time it is called and find the first frame without a score (the running score is stored on the frame), a frame can be asked what its score is, but it's kindof irrelevant as this is not shown on a scorecard, and it can't be done it a vacuum... i.e. if I have a strike or a spare in a frame, what is the frame score? You have to get the next two throws to figure that out... so I let the Score class do that and simply update the Frame score instVar once the calculation has been made. As soon as Scoreing hits a frame it cannot score, it stops and the Frame goes on to the next throw, or if it has hit maxThrows for the frame (frame1-9, maxThrows=2, frame10 maxThrows=3)... some folks call the third ball a bonus ball, I decided not to. So, when you get to frame10, we are allowed to have 3 throws if certain conditions are met - - your first throw is a strike, or - your second throw is a spare ... and of course scoring is a bit different for frame10, as well. I created a simulator with a traceCr output to show my frames and throws. Frame 1, 8 pins Throw 1, 6 pins Throw 2, 2 pins Score: 8 Frame 2, 9 pins Throw 1, 0 pins Throw 2, 9 pins Score: 17 Frame 3, 7 pins Throw 1, 5 pins Throw 2, 2 pins Score: 24 Frame 4, 9 pins Throw 1, 8 pins Throw 2, 1 pins Score: 33 Frame 5, 5 pins Throw 1, 3 pins Throw 2, 2 pins Score: 38 Frame 6, 6 pins Throw 1, 5 pins Throw 2, 1 pins Score: 44 Frame 7, 9 pins Throw 1, 4 pins Throw 2, 5 pins Score: 53 Frame 8, 8 pins Throw 1, 1 pins Throw 2, 7 pins Score: 61 Frame 9, 3 pins Throw 1, 3 pins Throw 2, 0 pins Score: 64 Frame 10, 15 pins Throw 1, 4 pins Throw 2, 6 pins Throw 3, 5 pins Score: 79 Final score: 79 Strikes: 0 Spares: 1 Gutters: 2 Timer >> 24.933ms Bowling-runTestGame I then tried my hand at a GUI - creating a BowlingPresenter, a ScorecardPresenter, a FramePresenter and a Frame10Presenter, resulting in... [image: image.png] I plan to add multi-player (or at least playing against the computer), but until I figure out how to make the throws be specific about which physical pins are remaining and the percentages of the next throw clearing them (much more complex that pure random) - there's not much else I can really do. So if anyone has direction for me on this, I'd love to try and tackle it sometime. Let me know if you have any questions. Thanks, Russ On Mon, Dec 21, 2020 at 5:05 AM r.wobben--- via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > Hello, > > > To come back at this one. > > I made a class Bowling and a class Frame which contains two instance > variables named firstThrow and secondThrow. > > > but I still wonder how do I know which one to fill in. > > I can do ` (firstThrow nil?) ` but that feels not right. > > > Is there a more idiomatic solution for this ? > > > Roelof > > > -- Russ Whaley whaley.russ(a)gmail.com

Dec. 21, 2020

[exercism bowling challenge] Is there a better way to do this

by r.wobben＠home.nl

Hello, To come back at this one. I made a class Bowling and a class Frame which contains two instance variables named firstThrow and secondThrow. but I still wonder how do I know which one to fill in. I can do \` (firstThrow nil?) \` but that feels not right. \ Is there a more idiomatic solution for this ? Roelof

Dec. 21, 2020

About BitBlt for non graphical problems

by Rafael Luque

Hi all, I remember to read in the Blue Book about a Game Of Life solution based on the BitBlt operation. I wondered if it was only a smart and elegant demonstration or it may be a useful tool in the case you need parallelism, even in non-graphical contexts. I've never seen BitBlt used to solve non-graphical problems, but I don't have experience with BitBlt in my everyday work, so maybe I'm biased. I've found a paper by Leo J. Guibas and Jorge Stolfi ( https://www.cs.tufts.edu/~nr/cs257/archive/leo-guibas/language-bitmap.pdf) about a "calculus of bitmap operations" including an specific language called MUMBLE, but I suspect it is not a common use case. Anyway, I've experimented with this option to solve the Advent of Code's Day 3 challenge. The puzzle consists of counting the number of trees you will encounter traversing a given map with open squares and trees, starting at the top-left corner and following a certain slope (( https://adventofcode.com/2020/day/3) After implementing the straight-forward and iterative solution, I tried using Form instances representing the map and the slope and a BitBlt operation for ANDing both forms in order to leave only bits where you encounter a tree (see attached image). In this alternative solution I like how the iteration is replaced by only one "BitBlt>>copyBits" operation. Additionally, I understand that BitBlt operations are native primitives that could be hardware optimized. However, I didn't know how to count the resulting bits without recurring again to the iteration of the Form's bits. This is my current implementation: AoCBitBltForestMap>>countTreesOnPath | mapForm | mapForm := self form. (BitBlt toForm: mapForm) copyForm: self slopeMaskForm to: 0 @ 0 rule: Form and. ^ mapForm bits count: [ :bit | (Color colorFromPixelValue: bit depth: 32) green closeTo: 1 precision: 0.1 ] You can find all the sources at the following repository: https://github.com/luque/AdventOfCode2020 Any comments about BitBlt use cases or this specific puzzle will be of interest for me. Thank you.

Dec. 21, 2020

Re: How coverage is computed with SmalltalkCI and coverall

by StÃ©phane Ducasse

Ok I could not see the MW or methods as object use but now I get it. So the granularity is already good. I would really like the support for coverage in Pharo ecosystem and not only on build system. I would really like that we push tests to the next level :). S > On 20 Dec 2020, at 19:08, BenoÃ®t Verhaeghe <badetitou(a)gmail.com> wrote: > > First, configuration looks for classes and packages ( look at .smalltalk.ston file ) > Second, you take all the methods inside the classes and packages. > If a method is an extension ( for instance, method A of class C is under package P. But class C is under package P2), then select all the methods of the class of the method ( this logic is under discussion in two issues of SmallTalkCI. > > Third, SmallTalkCI wraps each method ( install a wrapper in the method's class that is called instead of the real method ). > When a wrapper is called, marks a Boolean to true, and calls the original method. > > Finally, the coverage is the number of covered methods marked as true compare to the total number of covered method. > > ( Note : the wrapping is not done using reflectivity whereas it can be a good idea ? ) > > > > Le dim. 20 dÃ©c. 2020 Ã 18:29, StÃ©phane Ducasse <stephane.ducasse(a)inria.fr <mailto:stephane.ducasse@inria.fr>> a Ã©crit : > Thanks I could not find it. > I read the code and it is still unclear what is the logic. I could not figure out what we get lines here. > > I would like to resurrect the AST interpreter to get some information on AST level coverage. > What is see is that so far this is a heuristic that is used in SmalltalkCI. > > S. > >> On 20 Dec 2020, at 13:27, Gabriel Cotelli <g.cotelli(a)gmail.com <mailto:g.cotelli@gmail.com>> wrote: >> >> AFAIR is implemented in https://github.com/hpi-swa/smalltalkCI/tree/master/repository/SmalltalkCI-P… <https://github.com/hpi-swa/smalltalkCI/tree/master/repository/SmalltalkCI-P…> and it's superclass. >> >> On Sun, Dec 20, 2020, 05:44 StÃ©phane Ducasse <stephane.ducasse(a)inria.fr <mailto:stephane.ducasse@inria.fr>> wrote: >> Hi >> >> I would like to know exactly how the test coverage is computed. >> I read all the code of SmalltalkCi and I could not find it. >> >> S. >> -------------------------------------------- >> StÃ©phane Ducasse >> http://stephane.ducasse.free.fr <http://stephane.ducasse.free.fr/> / http://www.pharo.org <http://www.pharo.org/> >> 03 59 35 87 52 >> Assistant: Aurore Dalle >> FAX 03 59 57 78 50 >> TEL 03 59 35 86 16 >> S. Ducasse - Inria >> 40, avenue Halley, >> Parc Scientifique de la Haute Borne, BÃ¢t.A, Park Plaza >> Villeneuve d'Ascq 59650 >> France >> > > -------------------------------------------- > StÃ©phane Ducasse > http://stephane.ducasse.free.fr <http://stephane.ducasse.free.fr/> / http://www.pharo.org <http://www.pharo.org/> > 03 59 35 87 52 > Assistant: Aurore Dalle > FAX 03 59 57 78 50 > TEL 03 59 35 86 16 > S. Ducasse - Inria > 40, avenue Halley, > Parc Scientifique de la Haute Borne, BÃ¢t.A, Park Plaza > Villeneuve d'Ascq 59650 > France > -------------------------------------------- StÃ©phane Ducasse http://stephane.ducasse.free.fr / http://www.pharo.org 03 59 35 87 52 Assistant: Aurore Dalle FAX 03 59 57 78 50 TEL 03 59 35 86 16 S. Ducasse - Inria 40, avenue Halley, Parc Scientifique de la Haute Borne, BÃ¢t.A, Park Plaza Villeneuve d'Ascq 59650 France

Dec. 20, 2020