May 2020 - Pharo-users - lists.pharo.org

[ANN] Willow-SpinKit v8.0.0 [v8.0.0] released!
by Buenos Aires Smalltalk May 4, 2020

May 4, 2020

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[ANN] Willow-Bootstrap v12.0.0 [v12.0.0] released!
by Buenos Aires Smalltalk May 4, 2020

May 4, 2020

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ANN - Techtalk - Pharo Status May 2020
by tesonep＠gmail.com May 4, 2020

May 4, 2020

Techtalk: Pharo Status May 2020 Abstract: Pharo is moving fast, and sometimes it looks it is doing it in a chaotic way. However, we have a plan and a lot of things that we have accomplished in the past months. The idea of this talk is to present what has been done, where we are, and what are the things that we are working on. The idea of this talk is to be an open talk, where we can share the state but also listen to different ideas about what is important for the community. For so, I am attaching a presentation with the detail of the status, so we can start from it the conversation. When: Wednesday 6th May, 17h00 Paris Time / 15h00 UTC Where: #Techtalk channel in Pharo Discord Server. -- Pablo Tesone. tesonep(a)gmail.com

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Re: [Pharo-users] Thinking aloud about project at hand
by eftomi May 3, 2020

May 3, 2020

> I'm thinking about implementing a software solution in Pharo (as one of the candidate environments), it's > a project that I'm dealing with professionally. The goal is to develop a > financial planning/simulation > application on the country level, which is at present developed as a set > of interrelated Excel spreadsheets. > The requirement is that the solution should be more "manageable", > resilient and straightforward than > Excel permits, that it should present a workflow to the user - i.e. , that > the tasks the user should do are > suggested through the GUI. Thanks again for all the ideas regarding my project. So far I prepared the domain model and all the calculations. The model might be changed in the future, but that's basically it. Now I'm going to focus on the user's workflow and GUI. I have to say that I'm positively surprised by Pharo. Besides Pharo, I explored the feasibility of using other environments for the same project, namely VBA, .NET, Python. What took me in VBA and C#.NET roughly two weeks - and these are my 'native' programming environments - I finished in five days in Pharo. If GUI and finalization will go smoothly, this will be a success. I'm playing with Pharo for some time, but until now I haven't done any serious work with it. Nice! Best wishes, Tomaz -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

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Re: [Pharo-users] mentor question 4
by Ben Coman May 3, 2020

May 3, 2020

On Sat, 2 May 2020 at 15:52, Roelof Wobben via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > Op 1-5-2020 om 08:35 schreef Roelof Wobben: > >> On Fri, 1 May 2020 at 02:16, Roelof Wobben <r.wobben(a)home.nl> wrote: > >>> Op 30-4-2020 om 16:06 schreef Richard O'Keefe: > >>>> This sounds very much like the Luhn test task at RosettaCode. > >>>> https://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers > >>>> except that there it is described as working on the digits of an > >>>> integer. > >>>> > >>>> (1) There are two approaches to traversing a sequence in reverse. > >>>> (A) Reverse the sequence, then traverse the copy forward. > >>>> aString reverse do: [:each | ...] > >>>> (B) Just traverse the sequence in reverse > >>>> aString reverseDo: [:each | ...] > >>>> My taste is for the second. > >>>> > >>>> (2) There are two approaches to deleting spaces. > >>>> (A) Make a copy of the string without spaces. > >>>> x := aString reject: [:each | each = Character space]. > >>>> x do: ... > >>>> (B) Ignore spaces as you go: > >>>> (i) aString do: [:each | each = Character space ifFalse: > >>>> [...]] > >>>> (ii) aString select: [:each | each ~= Character space] > >>>> thenDo: > >>>> [:each | ...] > >>>> > >>>> Combining (1A) and (2A) you get very obvious code: > >>>> (aString reject: [:each | each = Character space]) reverse do: > >>>> [:digit } ...] > >>>> Combining (1B) and (2Bi) you get more efficient code: > >>>> aString reverseDo: [:digit | > >>>> digit = Character space ifFalse: [ ...]] > >>>> > >>>> By the way, let's start by checking that the character in the > >>>> string *are* > >>>> digits or spaces: > >>>> (aString allSatisfy: [:each | each isDigit or: [each = > >>>> Character s[ace]]) > >>>> ifFalse: [^false], > >>>> > >>>> (3) There are two approaches to doubling the even digits. > >>>> (A) Make a new string that starts as a copy and change every > >>>> second > >>>> digit from the right. > >>>> (B) Simply *act* as if this has been done; keep track of > >>>> whether the > >>>> current digit position is even or odd and multiply by 1 > >>>> or 2 as > >>>> appropriate. > >>>> nextIsOdd := true. > >>>> aString reverseDo: [:digit | > >>>> digit = Character space ifFalse: [ > >>>> nextIsOdd > >>>> ifTrue: [oddSum := ...] > >>>> ifFalse: [evenSum := ...]. > >>>> nextIsOdd := nextIsOdd not]]. > >>>> > >>>> I *like* code that traverses a data structure exactly once and > >>>> allocates no intermediate garbage, so I'd be making (B) choices. > >>>> > >>>> > >>> For me , I use this to practice solving problems and doing the > >>> "right" > >>> steps. > >>> So I love it , that so many people share there way of solving it. > >>> I can learn a lot from it > >>> Expecially when they explain there thinking process so detailed. > >>> > >>> I like this code also a lot. > >>> Am I correct for testing if it is a valid string by doing this ^ > >>> (oddSum + evenSum) dividedBy: 10 > >>> > >>> Roelof > >>> > > > > > > oke, > > > > so this is better > > > > cardNumber := '8273 1232 7352 0569'. > > oddSum := 0. > > evenSum := 0. > > nextIsOdd := false. > > cardNumber reverseDo: [:character | > > digit := character digitValue. > > character = Character space ifFalse: [ > > nextIsOdd > > ifFalse: [oddSum := oddSum + digit ] > > ifTrue: [(digit >= 5 ) > > ifTrue: [evenSum := evenSum + (digit * 2) - 9 ] > > ifFalse: [ evenSum := evenSum + (digit * 2) ]]. > > nextIsOdd := nextIsOdd not]]. > > ^ evenSum + oddSum // 10 == 0. > > > > > > where I could even make a seperate method of the ifTrue branch when > > the digit is greater then 5. > > > > > nobody who can say if this is a good solution ? > You didn't actually ask a question :) btw, Its good you are stretching yourself to do it the most complicated way, but pay attention that when Richard says HE "likes code that traverses a data structure exactly once" its because he is starting with the philosophy to OPTIMISE for EFFICIENCY. Often in programming that is the LAST thing you should do because to do so your code often becomes more complex, and Kernagan's law applies... https://talixa.com/blog/why-i-write-simple-code/ In general, you want to avoid premature optimization. https://effectiviology.com/premature-optimization/ The catch-phrase I see around this forum priorities things in this order: 1. Make it work. 2. Make it right. 3. Make it fast. and often you can stop at 2 because it is already "fast enough". Considering your code above, if I take TIME to go through it, I can evaluate that it seems right but I remain feeling that I could have missed something. Something like Richard's (A) examples without loops I would consider to be "more good". since each line can be dealt with individually. cardNumber := '4539 1488 0343 6467'. cleanDigits := cardNumber copyWithout: Character space. preWrapDigits := cleanDigits asArray collectWithIndex: [ :char :idx | (idx\\2 + 1) * char digitValue ]. wrappedDigits := preWrapDigits collect: [ :d | d > 9 ifFalse: [ d ] ifTrue: [ d-9 ] ]. ^ wrappedDigits sum isDivisibleBy: 10. A side benefit is having full result of each transformation available to be reviewed, rather than having only pieces of it in view when you debug a loop. In the end though, yours is a good solution first and foremost because tried a more detailed way and you got it working!! Remember there is more than one "good way" to do it depending on what you are optimising for - efficiency or readability. cheers -ben

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Re: [Pharo-users] mentor question 4
by Richard Sargent May 2, 2020

May 2, 2020

On Sat, May 2, 2020 at 12:38 PM Roelof Wobben via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > Op 2-5-2020 om 21:09 schreef Roelof Wobben via Pharo-users: > > > but this seems to work : > > cardNumber := '4539 1488 0343 6467'. > cleanDigits := cardNumber copyWithout: Character space. > preWrapDigits := (cleanDigits asArray reverse collectWithIndex: [ :char > :idx | (idx even) ifTrue: [ 2 * char digitValue ] ifFalse:[char > digitValue]]). > wrappedDigits := preWrapDigits collect: [ :d | d > 9 ifFalse: [ d ] > ifTrue: [ d-9 ] ]. > ^ wrappedDigits sum isDivisibleBy: 10. > > Can the code be more improved ? > As a general guideline, the best code will correspond closely to the documented algorithm. In this latest example, you have two visible loop iterations plus to hidden loop iterations. It also includes object creation from both #asArray and #reverse, the two messages with the hidden loop iteration. For this exercise, the number of loops and object creations isn't relevant. However, you always want to understand when you are doing such things. They will have an impact if they are used inside a high frequency loop. Again, that's not the case with this exercise. It often is in real world applications. But again, you should not optimize for performance at the expense of clarity and readability until you need to. And when you do need to, you annotate the code to explain how the implementation corresponds to or differs from the more comprehensible implementation. (Comments should explain the why and/or the background rather than the what.) > Roelof > > >

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Re: [Pharo-users] mentor question 4
by StÃ©phane Ducasse May 2, 2020

May 2, 2020

check with the finder and example S. > On 2 May 2020, at 21:09, Roelof Wobben <r.wobben(a)home.nl> wrote: > > > From: Roelof Wobben <r.wobben(a)home.nl> > Subject: Re: [Pharo-users] mentor question 4 > Date: 2 May 2020 at 21:09:12 CEST > To: Ben Coman <btc(a)openinworld.com>, Any question about pharo is welcome <pharo-users(a)lists.pharo.org> > > > Op 2-5-2020 om 19:33 schreef Ben Coman: >> >> >> On Sat, 2 May 2020 at 15:52, Roelof Wobben via Pharo-users <pharo-users(a)lists.pharo.org <mailto:pharo-users@lists.pharo.org>> wrote: >> Op 1-5-2020 om 08:35 schreef Roelof Wobben: >> >> On Fri, 1 May 2020 at 02:16, Roelof Wobben <r.wobben(a)home.nl <mailto:r.wobben@home.nl>> wrote: >> >>> Op 30-4-2020 om 16:06 schreef Richard O'Keefe: >> >>>> This sounds very much like the Luhn test task at RosettaCode. >> >>>> https://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers <https://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers> >> >>>> except that there it is described as working on the digits of an >> >>>> integer. >> >>>> >> >>>> (1) There are two approaches to traversing a sequence in reverse. >> >>>> (A) Reverse the sequence, then traverse the copy forward. >> >>>> aString reverse do: [:each | ...] >> >>>> (B) Just traverse the sequence in reverse >> >>>> aString reverseDo: [:each | ...] >> >>>> My taste is for the second. >> >>>> >> >>>> (2) There are two approaches to deleting spaces. >> >>>> (A) Make a copy of the string without spaces. >> >>>> x := aString reject: [:each | each = Character space]. >> >>>> x do: ... >> >>>> (B) Ignore spaces as you go: >> >>>> (i) aString do: [:each | each = Character space ifFalse: >> >>>> [...]] >> >>>> (ii) aString select: [:each | each ~= Character space] >> >>>> thenDo: >> >>>> [:each | ...] >> >>>> >> >>>> Combining (1A) and (2A) you get very obvious code: >> >>>> (aString reject: [:each | each = Character space]) reverse do: >> >>>> [:digit } ...] >> >>>> Combining (1B) and (2Bi) you get more efficient code: >> >>>> aString reverseDo: [:digit | >> >>>> digit = Character space ifFalse: [ ...]] >> >>>> >> >>>> By the way, let's start by checking that the character in the >> >>>> string *are* >> >>>> digits or spaces: >> >>>> (aString allSatisfy: [:each | each isDigit or: [each = >> >>>> Character s[ace]]) >> >>>> ifFalse: [^false], >> >>>> >> >>>> (3) There are two approaches to doubling the even digits. >> >>>> (A) Make a new string that starts as a copy and change every >> >>>> second >> >>>> digit from the right. >> >>>> (B) Simply *act* as if this has been done; keep track of >> >>>> whether the >> >>>> current digit position is even or odd and multiply by 1 >> >>>> or 2 as >> >>>> appropriate. >> >>>> nextIsOdd := true. >> >>>> aString reverseDo: [:digit | >> >>>> digit = Character space ifFalse: [ >> >>>> nextIsOdd >> >>>> ifTrue: [oddSum := ...] >> >>>> ifFalse: [evenSum := ...]. >> >>>> nextIsOdd := nextIsOdd not]]. >> >>>> >> >>>> I *like* code that traverses a data structure exactly once and >> >>>> allocates no intermediate garbage, so I'd be making (B) choices. >> >>>> >> >>>> >> >>> For me , I use this to practice solving problems and doing the >> >>> "right" >> >>> steps. >> >>> So I love it , that so many people share there way of solving it. >> >>> I can learn a lot from it >> >>> Expecially when they explain there thinking process so detailed. >> >>> >> >>> I like this code also a lot. >> >>> Am I correct for testing if it is a valid string by doing this ^ >> >>> (oddSum + evenSum) dividedBy: 10 >> >>> >> >>> Roelof >> >>> >> > >> > >> > oke, >> > >> > so this is better >> > >> > cardNumber := '8273 1232 7352 0569'. >> > oddSum := 0. >> > evenSum := 0. >> > nextIsOdd := false. >> > cardNumber reverseDo: [:character | >> > digit := character digitValue. >> > character = Character space ifFalse: [ >> > nextIsOdd >> > ifFalse: [oddSum := oddSum + digit ] >> > ifTrue: [(digit >= 5 ) >> > ifTrue: [evenSum := evenSum + (digit * 2) - 9 ] >> > ifFalse: [ evenSum := evenSum + (digit * 2) ]]. >> > nextIsOdd := nextIsOdd not]]. >> > ^ evenSum + oddSum // 10 == 0. >> > >> > >> > where I could even make a seperate method of the ifTrue branch when >> > the digit is greater then 5. >> > >> > >> nobody who can say if this is a good solution ? >> >> You didn't actually ask a question :) >> >> btw, Its good you are stretching yourself to do it the most complicated way, >> but pay attention that when Richard says HE "likes code that traverses a data structure exactly once" >> its because he is starting with the philosophy to OPTIMISE for EFFICIENCY. >> Often in programming that is the LAST thing you should do because to do so your code often becomes more complex, >> and Kernagan's law applies... >> https://talixa.com/blog/why-i-write-simple-code/ <https://talixa.com/blog/why-i-write-simple-code/> >> >> In general, you want to avoid premature optimization. >> https://effectiviology.com/premature-optimization/ <https://effectiviology.com/premature-optimization/> >> >> The catch-phrase I see around this forum priorities things in this order: >> 1. Make it work. >> 2. Make it right. >> 3. Make it fast. >> and often you can stop at 2 because it is already "fast enough". >> >> Considering your code above, if I take TIME to go through it, I can evaluate that it seems right >> but I remain feeling that I could have missed something. >> >> Something like Richard's (A) examples without loops I would consider to be "more good". >> since each line can be dealt with individually. >> >> cardNumber := '4539 1488 0343 6467'. >> cleanDigits := cardNumber copyWithout: Character space. >> preWrapDigits := cleanDigits asArray collectWithIndex: [ :char :idx | (idx\\2 + 1) * char digitValue ]. >> wrappedDigits := preWrapDigits collect: [ :d | d > 9 ifFalse: [ d ] ifTrue: [ d-9 ] ]. >> ^ wrappedDigits sum isDivisibleBy: 10. >> >> A side benefit is having full result of each transformation available to be reviewed, >> rather than having only pieces of it in view when you debug a loop. >> >> In the end though, yours is a good solution first and foremost because tried a more detailed way and you got it working!! >> Remember there is more than one "good way" to do it depending on what you are optimising for - efficiency or readability. >> >> cheers -ben >> > > I think I find readability more important then efficieny. > > But I think I have to alter your code. At first look it does not look like that every second value from the right is multiplied by 2. > > When the index is for example 7 . > > 7 // 2 gives 3. > Maybe it needs to be %. > > Roelof > > -------------------------------------------- StÃ©phane Ducasse http://stephane.ducasse.free.fr / http://www.pharo.org 03 59 35 87 52 Assistant: Julie Jonas 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

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Re: [Pharo-users] mentor question 4
by Roelof Wobben May 2, 2020

May 2, 2020

Op 2-5-2020 om 21:09 schreef Roelof Wobben via Pharo-users: but this seems to work : cardNumber := '4539 1488 0343 6467'. cleanDigits := cardNumber copyWithout: Character space. preWrapDigits := (cleanDigits asArray reverse collectWithIndex: [ :char :idx | (idx even) ifTrue: [ 2 * char digitValue ] ifFalse:[char digitValue]]). wrappedDigits :=Â preWrapDigits collect: [ :d | d > 9 ifFalse: [ d ] ifTrue: [ d-9 ] ]. ^ wrappedDigits sum isDivisibleBy: 10. Can the code be more improved ? Roelof

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Re: [Pharo-users] mentor question 4
by Richard Sargent May 2, 2020

May 2, 2020

It's a good solution. On Sat, May 2, 2020, 00:52 Roelof Wobben via Pharo-users < pharo-users(a)lists.pharo.org> wrote: > Op 1-5-2020 om 08:35 schreef Roelof Wobben: > > Op 1-5-2020 om 02:51 schreef Richard O'Keefe: > >> (oddSum + evenSum) dividedBy: 10 > >> > >> You previously had _ isDivisibleBy: 10 > >> which certainly works. > >> > >> Squeak, Pharo, and ST/X have #isDivisibleBy: > >> VisualWorks. Dolphin, and GNU Smalltalk do not. > >> > >> Here's the code from Number.st in ST/X. > >> isDivisibleBy:aNumber > >> "return true, if the receiver can be divided by the argument, > >> aNumber without a remainder. > >> Notice, that the result is only worth trusting, if the receiver > >> is an integer." > >> > >> aNumber = 0 ifTrue: [^ false]. > >> aNumber isInteger ifFalse: [^ false]. > >> ^ (self \\ aNumber) = 0 > >> > >> The comment is wrong: the question makes sense for any combination > >> of exact numbers. > >> When, as in this case, aNumber is a literal integer, all > >> #isDivisibleBy: really adds is overhead. > >> > >> (oddSum + evenSum) \\ 10 = 0 > >> > >> is quite clear, and completely portable. > >> > >> > >> > >> On Fri, 1 May 2020 at 02:16, Roelof Wobben <r.wobben(a)home.nl> wrote: > >>> Op 30-4-2020 om 16:06 schreef Richard O'Keefe: > >>>> This sounds very much like the Luhn test task at RosettaCode. > >>>> https://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers > >>>> except that there it is described as working on the digits of an > >>>> integer. > >>>> > >>>> (1) There are two approaches to traversing a sequence in reverse. > >>>> (A) Reverse the sequence, then traverse the copy forward. > >>>> aString reverse do: [:each | ...] > >>>> (B) Just traverse the sequence in reverse > >>>> aString reverseDo: [:each | ...] > >>>> My taste is for the second. > >>>> > >>>> (2) There are two approaches to deleting spaces. > >>>> (A) Make a copy of the string without spaces. > >>>> x := aString reject: [:each | each = Character space]. > >>>> x do: ... > >>>> (B) Ignore spaces as you go: > >>>> (i) aString do: [:each | each = Character space ifFalse: > >>>> [...]] > >>>> (ii) aString select: [:each | each ~= Character space] > >>>> thenDo: > >>>> [:each | ...] > >>>> > >>>> Combining (1A) and (2A) you get very obvious code: > >>>> (aString reject: [:each | each = Character space]) reverse do: > >>>> [:digit } ...] > >>>> Combining (1B) and (2Bi) you get more efficient code: > >>>> aString reverseDo: [:digit | > >>>> digit = Character space ifFalse: [ ...]] > >>>> > >>>> By the way, let's start by checking that the character in the > >>>> string *are* > >>>> digits or spaces: > >>>> (aString allSatisfy: [:each | each isDigit or: [each = > >>>> Character s[ace]]) > >>>> ifFalse: [^false], > >>>> > >>>> (3) There are two approaches to doubling the even digits. > >>>> (A) Make a new string that starts as a copy and change every > >>>> second > >>>> digit from the right. > >>>> (B) Simply *act* as if this has been done; keep track of > >>>> whether the > >>>> current digit position is even or odd and multiply by 1 > >>>> or 2 as > >>>> appropriate. > >>>> nextIsOdd := true. > >>>> aString reverseDo: [:digit | > >>>> digit = Character space ifFalse: [ > >>>> nextIsOdd > >>>> ifTrue: [oddSum := ...] > >>>> ifFalse: [evenSum := ...]. > >>>> nextIsOdd := nextIsOdd not]]. > >>>> > >>>> I *like* code that traverses a data structure exactly once and > >>>> allocates no intermediate garbage, so I'd be making (B) choices. > >>>> > >>>> > >>> For me , I use this to practice solving problems and doing the > >>> "right" > >>> steps. > >>> So I love it , that so many people share there way of solving it. > >>> I can learn a lot from it > >>> Expecially when they explain there thinking process so detailed. > >>> > >>> I like this code also a lot. > >>> Am I correct for testing if it is a valid string by doing this ^ > >>> (oddSum + evenSum) dividedBy: 10 > >>> > >>> Roelof > >>> > > > > > > oke, > > > > so this is better > > > > cardNumber := '8273 1232 7352 0569'. > > oddSum := 0. > > evenSum := 0. > > nextIsOdd := false. > > cardNumber reverseDo: [:character | > > digit := character digitValue. > > character = Character space ifFalse: [ > > nextIsOdd > > ifFalse: [oddSum := oddSum + digit ] > > ifTrue: [(digit >= 5 ) > > ifTrue: [evenSum := evenSum + (digit * 2) - 9 ] > > ifFalse: [ evenSum := evenSum + (digit * 2) ]]. > > nextIsOdd := nextIsOdd not]]. > > ^ evenSum + oddSum // 10 == 0. > > > > > > where I could even make a seperate method of the ifTrue branch when > > the digit is greater then 5. > > > > > nobody who can say if this is a good solution ? > > Roelof > >

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Spec2 SpStringTableColumn
by TomaÅ¾ Turk May 2, 2020

May 2, 2020

Dear all, I'm exploring the new Spec2, looking for possibilities to create an 'editable grid'. Tables are very close to this concept, and I wonder what exactly is SpStringTableColumn>>#beEditable supposed to do - I cannot find any references to variable 'editable', so it looks like it's not implemented yet? Could editable grid be mimicked somehow with SpCompositeTableColumn? Besides this, I wonder whether Spec2 could control keyboard events? Many thanks and best wishes, Tomaz

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