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

Re: [Pharo-users] Prof Stef questions

by xap

>> It is always a good idea to describe in detail what behaviour you did observe. "get an error" is the same as "it didn't work". you're correct, and I should know better! >> You are *evaluating* one of the two blocks in the #ifTrue:ifFalse: >> expression this is clutch; thx for the insight! -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Jan. 6, 2020

Re: [Pharo-users] is this better regarding naming thigs

by xap

"but all objects respond to value..."; thx, Santiago -- that makes more sense, that or: cares only about its receiver/argument evaluable as a Boolean, no matter they started as blocks, expressions, or something else (makes me wonder if a bare-value is a degenerate case of a block ... but don't mind me, I'm just talking aloud). separately, point taken re expressions being evaluated, and blocks possibly not. -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Jan. 6, 2020

Re: [Pharo-users] How can we celebrate the 50th anniversary of Smalltalk?

by Vince Refiti

Even better, to somehow port Pharo to the BEAM, like Ruby/Elixir. -----Original Message----- From: Pharo-users [mailto:pharo-users-bounces@lists.pharo.org] On Behalf Of ponyatov Sent: Monday, 6 January 2020 1:39 AM To: pharo-users(a)lists.pharo.org Subject: Re: [Pharo-users] How can we celebrate the 50th anniversary of Smalltalk? EXTERNAL: Do not click links or open attachments if you do not recognize the sender. The best tribute to 50th anniversary will be the implementation of distributed multi-user VM. -- Sent from: https://urldefense.com/v3/__http://forum.world.st/Pharo-Smalltalk-Users-f13…

Jan. 5, 2020

Re: [Pharo-users] is this better regarding naming thigs

by Santiago Dandois

It's better (conceptually and in performance) to use the inner block, but is not always necessary. The #or: message sends the `value` message to it's collaborator if the bolean is false. Blocks responds to value executing theirs code, but all objects respond to value since it's defined in the Object class as ^self. Therefore, the result is the same but the messages involved and the order in which they are being sent are not. In performance, for the case where the first bolean was true, is better the one with the surrounding block , since the code inside it is never being executed. You should really try both versions with the debugger to see it by yourself. Cheers, Santiago Dandois El dom., 5 ene. 2020 a las 19:53, xap (<xap(a)router.33mail.com>) escribiÃ³: > thx Rixhard. looks like or: takes an 'alternativeBlock', i.e. a block. > however substituting a parenthesized expression (or what i assume is one) > as > I did before, in place of the inner block, w/ no other changes has the > method continue to work as expected, hence my question. *shrug* i need to > rtfm :-/ > > > > -- > Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html > >

Jan. 5, 2020

Re: [Pharo-users] is this better regarding naming thigs

by xap

thx Rixhard. looks like or: takes an 'alternativeBlock', i.e. a block. however substituting a parenthesized expression (or what i assume is one) as I did before, in place of the inner block, w/ no other changes has the method continue to work as expected, hence my question. *shrug* i need to rtfm :-/ -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Jan. 5, 2020

Re: [Pharo-users] is this better regarding naming thigs

by Richard Sargent

On Sun, Jan 5, 2020, 15:51 xap <xap(a)router.33mail.com> wrote: > hi, I'm just starting out w/ pharo and have a question re your code; > specifically, in > > reject: > [ :word | (word sameAs: aWord) or: [ word asLowercase asBag ~= > charBag ] ] > > is that inner block needed? would it be less smalltalk-esque to write, say: > > reject: > [ :w | (w = aWord) or: (w asLowercase asBag ~= charBag) ] > > thx! > The answer to your question is provided by looking at the definition of the #or: message. Specifically, look on the class Boolean and its subclasses. They should tell you what kinds of objects are allowed for the argument. There is also an #| message which does what you have asked the #or: message to do. Study the differences in their definitions in the Boolean hierarchy. > separately recently I watched an alan kay interview in which he says an oo > program is typically much smaller than its imperative counterpart and i > wondered why. Well, it seems that reduction comes from the language/system > providing a zillion methods -- asBag, here -- one would otherwise need to > implement, oneself :) > > > > -- > Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html > >

Jan. 5, 2020

Re: [Pharo-users] is this better regarding naming thigs

by xap

hi, I'm just starting out w/ pharo and have a question re your code; specifically, in reject: [ :word | (word sameAs: aWord) or: [ word asLowercase asBag ~= charBag ] ] is that inner block needed? would it be less smalltalk-esque to write, say: reject: [ :w | (w = aWord) or: (w asLowercase asBag ~= charBag) ] thx! separately recently I watched an alan kay interview in which he says an oo program is typically much smaller than its imperative counterpart and i wondered why. Well, it seems that reduction comes from the language/system providing a zillion methods -- asBag, here -- one would otherwise need to implement, oneself :) -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Jan. 5, 2020

[seaside] how can I now make the best work to display all the paiintings which are in the paintings collection

by Roelof Wobben

Hello, Im a little bit further on my first project but now I fail to see how I can use the ListComponent to display all the paintings that are in the paintings collection on the Paintings class. Anyone who can give me hints on this ? Roelof

Jan. 5, 2020

Re: [Pharo-users] can I make this so the vm would not be not responsibe when running the tests

by Ben Coman

Hi Richard, Just fyi, the aim of Exercism is not to teach programming. Its aim is for experienced programmers to fast-start in new languages. It just happens to that new programmers also use Exercism and there is some catering in the exercise text for this. The grains exercise provides a nice vehicle for programmers to familiarize themselves with recursion in Pharo, and the hint for the exercise says "These kinds of problems (where an answer is dependent on a previous) one are often called recursion" which is why Roelof is approaching the problem this way. That said, any solution will do. Your advice on alternative considerations is insightful and always good to read. cheers -ben On Mon, 6 Jan 2020 at 00:25, Richard O'Keefe <raoknz(a)gmail.com> wrote: > I did not ask why you were validating input. > I asked about why you *repeatedly* validated input. > > Think of it this way: > publicMethod: arg1 also: arg2 > ... check arg1 ... > ... check arg2 ... > ^self privateMethod: arg1 also: arg2 > > privateMethod: arg1 also: arg2 > ... trust that arg1 and arg2 are valide ... > ... recursive calls use #privateMethod:andAlso: ... > ... not #publicMethod:andAlso: and must ensure ... > ... that arguments are valid by construction ... > > In my solution to the "Grains" exercism, I have > atSquare: n -- checks its argument > total ^(1 bitShift: 64) - 1 > You are required to implement these two methods, true. > You are NOT required to implement #total by calling #atSquare:. > Not even once. Nor is #atSquare: required to be recursive. > > On Mon, 6 Jan 2020 at 02:05, Roelof Wobben <r.wobben(a)home.nl> wrote: > > > > Hello Ricard. > > > > You mean when I calcualate the total of a board. > > That is because on when I had to calculate the number of a particular > > field there were tests where the number was lower then zero or higher > > then 64 which makes no sense. > > > > But im open for a solution where on a particular field I could check for > > that and for the total I do not need that part. > > > > Roelof > > > > > > > > Op 5-1-2020 om 13:58 schreef Richard O'Keefe: > > > Time microsecondsToRun: [ > > > |n| > > > n := (2 raisedToInteger: 8 * 8) - 1. > > > Transcript > > > nextPutAll: 'The number of grains on an 8x8 chessboard is '; > > > print: n; cr; endEntry]. > > > <PRINT-IT> > > > On my laptop, this reports 194 microseconds. > > > > > > Why would you use recursion, anyway? > > > > > > Time microsecondsToRun: [ > > > |n| > > > n := (1 to: 8 * 8) inject: 0 into: [:acc :each | acc+acc+1]. > > > Transcript > > > nextPutAll: 'The number of grains on an 8x8 chessboard is '; > > > print: n; cr; endEntry]. > > > <PRINT-IT> > > > On the same laptop, this reports 118 microseconds. > > > > > > One of the lessons of 'functional' languages, promptly adopted by > Smalltalk, is > > > to encapsulate control structures into reusable methods, such as > #inject:into:, > > > more commonly known as `foldl` in functional languages. It's then > none of > > > my business whether such a method works by recursion, iteration, or > gangs > > > of otherwise seasonally unemployed Christmas elves. > > > > > > In my own Smalltalk library, > > > (GeometricSeries new: 64 from: 1 byFactor: 2) sum > > > only takes 15 microseconds. > > > > > > I do note that you are calling validateInput repeatedly. Why? > > > > > > > > > On Sun, 5 Jan 2020 at 07:41, Roelof Wobben via Pharo-users > > > <pharo-users(a)lists.pharo.org> wrote: > > >> Oke, > > >> > > >> So I can better not use recursion for this problem if I understand > you well, Richard. > > >> > > >> Roelof > > >> > > >> > > >> > > >> Op 4-1-2020 om 19:02 schreef Richard Sargent: > > >> > > >> On Sat, Jan 4, 2020 at 9:47 AM Roelof Wobben via Pharo-users < > pharo-users(a)lists.pharo.org> wrote: > > >>> Hello, > > >>> > > >>> For a exercism challenge I need to calculate the total grains on a > > >>> chessboard. > > >>> So I did : > > >>> > > >>> atSquare: anInteger > > >>> self validateInput: anInteger. > > >>> ^ anInteger = 1 > > >>> ifTrue: [ 1 ] > > >>> ifFalse: [ 2 * (self atSquare: anInteger - 1) ] > > >>> > > >>> > > >>> but when I run the tests , the vm seems to be not responsive for > some 4 > > >>> - 5 seconds. > > >>> > > >>> Is there a way I can use this code and take care that the vm stays > > >>> responsive. > > >> > > >> What do you want the VM to do in addition to calculating that sum > while it is calculating that sum? > > >> > > >> > > >> The best way to keep the VM responsive is to take a page from Gauss' > notebook and pay attention to the numbers[1]. Let's consider the first four > squares and extrapolate from there. > > >> > > >> In binary, the squares hold the following grains: 2r1, 2r10, r2100, > and 2r1000. When we add them up, we get 2r1111. If we use Gauss' tricks, we > can notice that 2r1111 is equal to 2r10000 - 1. So, the sum of the grains > on the first 4 squares is 2^5 - 1. You can easily generalize that pattern, > of course. Then your program can calculate the answer quickly. > > >> > > >> > > >> [1] The story goes that Gauss' teacher was frustrated with his > student's abilities and set him a challenge to occupy him for some time: > sum the numbers from 1 through 100. Gauss immediately answered 5,050, much > to his teacher's chagrin. > > >> > > >>> Regards, > > >>> > > >>> Roelof > > >>> > > >>> > > > >

Jan. 5, 2020

Re: [Pharo-users] How can we celebrate the 50th anniversary of Smalltalk?

by tbrunz

Did Smalltalk start with Smalltalk-72 or Smalltalk-80? (Or 1969, when work on it began..??) ST-72 was an internal release; ST-80 was its first public release, in 1980. I've always thought that 1980 was the birthday, so this year it turns 40... Am I wrong? What's the consensus? Is it customary to go by the project start date, the first stable version, the first release to the public, or what? -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Jan. 5, 2020