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Re: [Pharo-users] how to write this without a if then

by Sven Van Caekenberghe

> On 28 Nov 2018, at 06:15, Richard O'Keefe <raoknz(a)gmail.com> wrote: > > The idea of a flat ban on #ifTrue:ifFalse: is ridiculous. > Number>>abs > ^self negative ifTrue: [self negated] ifFalse: [self] > > Is there any better way to do this? Not really, you can > only move the #ifTrue:ifFalse: somewhere else. > > The main argument against #ifTrue:ifFalse: is NOT TO USE > IT FOR TYPE TESTS. If you want to do different things > depending on the class of x, ask x to do it. (The irony > is that in Smalltalk, #ifTrue:ifFalse: *is* in principle > an object-oriented dispatch.) If you want to do > different things depending on the state of x, and this > requires revealing internal details that would not > otherwise be revealed, ask x to do it. > > Two key ideas in software engineering are coupling > (lots of interdependencies makes things hard to re-use) > and cohesion (modules/types/classes should be "about" > one thing). You have to balance the "use OO dispatch" > idea against this: you have a method in class A that > depends on an object of class B, and you don't want > A to have to know too much about B, but on the other > hand, you don't want B to have to depend too much on > what A is up to. If it makes sense to have a B without > any A around, then changes to A should not really > require changes to B. > > So eliminating #ifTrue:ifFalse: from your code can make > it WORSE. You have to THINK about each task and decide > where it REALLY belongs. Is this bit of code entirely > about B? Then it belongs in B. Is that bit of code > about already public information concerning B and also > tied to A's needs and wants? Then it belongs in A. And > if that means using some sort of "if", go ahead! Very well written, thanks. > The Pharo 6 sources contain about 5800 classes and > over 40000 ifTrue:/ifFalse:/ifNil:/ifNotNil: uses. > The Dolphin core contains about 2100 clases and > over 12600 ifs. > My Smalltalk has about 13 ifs per class. > Smalltalk/X (JV) has about 6500 classes and > over 127000 ifs, nearly 20 per class. > > > > On Wed, 28 Nov 2018 at 05:41, Roelof Wobben <r.wobben(a)home.nl> wrote: > Hello, > > Yesterday I had a talk with luc frabresse about using if then. > He said if I understand it right, Its the best to not using a if then or > a ifTrue/ifFalse. > > Can anyone help me figure out how to rewrite this project so I will not > use the ifTrue in the basement function. > > my code so far can be found here : https://github.com/RoelofWobben/AOC2015 > > Roelof > >

Nov. 28, 2018

Re: [Pharo-users] how to write this without a if then

by Richard O'Keefe

The idea of a flat ban on #ifTrue:ifFalse: is ridiculous. Number>>abs ^self negative ifTrue: [self negated] ifFalse: [self] Is there any better way to do this? Not really, you can only move the #ifTrue:ifFalse: somewhere else. The main argument against #ifTrue:ifFalse: is NOT TO USE IT FOR TYPE TESTS. If you want to do different things depending on the class of x, ask x to do it. (The irony is that in Smalltalk, #ifTrue:ifFalse: *is* in principle an object-oriented dispatch.) If you want to do different things depending on the state of x, and this requires revealing internal details that would not otherwise be revealed, ask x to do it. Two key ideas in software engineering are coupling (lots of interdependencies makes things hard to re-use) and cohesion (modules/types/classes should be "about" one thing). You have to balance the "use OO dispatch" idea against this: you have a method in class A that depends on an object of class B, and you don't want A to have to know too much about B, but on the other hand, you don't want B to have to depend too much on what A is up to. If it makes sense to have a B without any A around, then changes to A should not really require changes to B. So eliminating #ifTrue:ifFalse: from your code can make it WORSE. You have to THINK about each task and decide where it REALLY belongs. Is this bit of code entirely about B? Then it belongs in B. Is that bit of code about already public information concerning B and also tied to A's needs and wants? Then it belongs in A. And if that means using some sort of "if", go ahead! The Pharo 6 sources contain about 5800 classes and over 40000 ifTrue:/ifFalse:/ifNil:/ifNotNil: uses. The Dolphin core contains about 2100 clases and over 12600 ifs. My Smalltalk has about 13 ifs per class. Smalltalk/X (JV) has about 6500 classes and over 127000 ifs, nearly 20 per class. On Wed, 28 Nov 2018 at 05:41, Roelof Wobben <r.wobben(a)home.nl> wrote: > Hello, > > Yesterday I had a talk with luc frabresse about using if then. > He said if I understand it right, Its the best to not using a if then or > a ifTrue/ifFalse. > > Can anyone help me figure out how to rewrite this project so I will not > use the ifTrue in the basement function. > > my code so far can be found here : https://github.com/RoelofWobben/AOC2015 > > Roelof > > >

Nov. 28, 2018

Re: [Pharo-users] Loading Metacello with Seaside

by Cyril Ferlicot D.

Le 28/11/2018 Ã 00:08, Vitor Medina Cruz a Ã©critÂ : > Hello! > > WIndows 10 here with Pharo 7 32 bits. Here is my baseline: > > > baseline: spec > Â Â Â > Â Â Â <baseline> > Â Â Â Â Â Â Â > Â Â Â spec for: #'common' do: [ > Â Â Â Â Â Â spec blessing: #'baseline'; > Â Â Â Â Â Â Â Â Â Â repository: 'gitlab://vitormcruz/employees:master/pharo/'; > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â > Â Â Â Â Â Â Â Â Â Â project: 'Magritte3' with: [ spec repository: > 'github://magritte-metamodel/magritte:v3.5.3/source'; > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â className: > 'ConfigurationOfMagritte3'; > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â loads: #(Seaside > Core) ]; > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â > Â Â Â Â Â Â Â Â Â Â package: 'Employees' with: [ spec requires: > #('Magritte3'). ]; > Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â > Â Â Â Â Â Â Â Â Â Â Â group: 'default' with: #('core'); > Â Â Â Â Â Â Â Â Â Â group: 'core' with: #('Employees') > > > > When I execute: > > Metacello new baseline: #Employees; > Â Â Â Â Â Â Â Â Â Â Â Â Â repository: > 'gitlab://vitormcruz/employees:master/pharo/'; load: #(core) > > > I got: > > "project group, or package named: 'Seaside-Pharo-Development' not > found when used in requires: or includes: field of package: > 'Seaside-Tests-Pharo-Development' for version: baseline of > BaselineOfSeaside3." > > > > It seems there is a problem with Magrite ConfigurationOf, am I correct? > > > Some general information: > > 1- Using https://github.com/magritte-metamodel/magritte instead > /magritte:v3.5.3/ of 'github://magritte-metamodel/magritte:v3.5.3/source > don't work; > > 2- You must provide className otherwise it does no work, even if docs > says itis not needed; > > 3- Metacello fail in ways it is hard to understand what happened; > > 4- On Pharo 64bits, Iceberg commit fails. > > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_cam…> > Livre de vÃrus. www.avg.com > <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_cam…>. > > > <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> Hi, Personally I declare my Magritte dependency with the Seaside group this way: spec baseline: 'Magritte' with: [ spec loads: #('Seaside'); repository: 'github://magritte-metamodel/magritte:v3.5.3/source' ]. If it can help you, here is a recent guide to Baselines: https://github.com/pharo-tips-and-tricks/pharo-tips-and-tricks/blob/master/… -- Cyril Ferlicot https://ferlicot.fr

Nov. 27, 2018

Loading Metacello with Seaside

by Vitor Medina Cruz

Hello! WIndows 10 here with Pharo 7 32 bits. Here is my baseline: baseline: spec > > <baseline> > > spec for: #'common' do: [ > spec blessing: #'baseline'; > repository: 'gitlab://vitormcruz/employees:master/pharo/'; > > project: 'Magritte3' with: [ spec repository: > 'github://magritte-metamodel/magritte:v3.5.3/source'; > className: > 'ConfigurationOfMagritte3'; > loads: #(Seaside Core) > ]; > > package: 'Employees' with: [ spec requires: #('Magritte3'). > ]; > > group: 'default' with: #('core'); > group: 'core' with: #('Employees') When I execute: Metacello new baseline: #Employees; > repository: > 'gitlab://vitormcruz/employees:master/pharo/'; load: #(core) > I got: "project group, or package named: 'Seaside-Pharo-Development' not found > when used in requires: or includes: field of package: > 'Seaside-Tests-Pharo-Development' for version: baseline of > BaselineOfSeaside3." > It seems there is a problem with Magrite ConfigurationOf, am I correct? Some general information: 1- Using https://github.com/magritte-metamodel/magritte instead /magritte:v3.5.3/ of 'github://magritte-metamodel/magritte:v3.5.3/source don't work; 2- You must provide className otherwise it does no work, even if docs says itis not needed; 3- Metacello fail in ways it is hard to understand what happened; 4- On Pharo 64bits, Iceberg commit fails. <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_cam…> Livre de vÃrus. www.avg.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_cam…>. <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>

Nov. 27, 2018

Re: [Pharo-users] Playing with Pharo 7

by Vitor Medina Cruz

The documentation on the book has much more information than needed to use Metacello with Iceberg, it can confuse you more than help I am afraid, at least this happened to me. The guide provided by Cyril is what you want. <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_cam…> Livre de vÃrus. www.avg.com <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_cam…>. <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> On Tue, Nov 27, 2018 at 8:01 AM Steffen MÃ¤rcker <merkste(a)web.de> wrote: > Great! > > Am .11.2018, 21:47 Uhr, schrieb Cyril Ferlicot D. > <cyril.ferlicot(a)gmail.com>: > > > Le 26/11/2018 Ã 16:57, Konrad Hinsen a Ã©crit : > >> > >> Thanks for the pointer! Unfortunately all the documentation there > >> assumes way more familiarity with Smalltalk than I have. And even a lot > >> of familiarity with Metacello itself, as the documentation only explains > >> the latest functionality. > >> > >> The good news is that it refers to "Deep into Pharo", so I will download > >> that book and see if answers my questions. > >> > >> Konrad. > >> > > > > Hello, > > > > There is also a recent guide here: > > > https://github.com/pharo-tips-and-tricks/pharo-tips-and-tricks/blob/master/… > > > > I don't know if it is more beginner friendly. Feedback is welcome. > > > > > >

Nov. 27, 2018

Re: [Pharo-users] Problems with Firmata & Arduino UNO Clone

by Ben Coman

On Tue, 27 Nov 2018 at 05:59, William L. Cleveland <wlc1(a)columbia.edu> wrote: > I have been unsuccessful in using an Arduino board with Pharo 6.1(32bit) > and the Firmata package. > > > > The board is an Arduino Uno clone (ELEGOO UNO R3). The board appears to > work fine with the Arduino IDE, which was tested with the BLINK program. > The Standard Firmata Library appears to have been successfully uploaded to > the board using the Arduino IDE. > > > > COM ports have been closed using > > SerialPort allInstancesDo: [:port|port close]. > > On Windows 10, SerialPort inspect shows that ports are closed. However, > firmata := Firmata onPort: âCOM3â baudRate: 576000 failed due to failure to > open COM3. The serial port name was obtained from the Arduino IDE Tools > menu. The board choice was âArduino Unoâ. > Was the Arduino IDE closed before you started Pharo? Or further, try Pharo immediately after booting your PC. cheers -ben >

Nov. 27, 2018

Re: [Pharo-users] Problems with Firmata & Arduino UNO Clone

by Denis Kudriashov

Hi William. I think Serial port does not work in MacOS VM. Ð¿Ð½, 26 Ð½Ð¾ÑÐ±. 2018 Ð³. Ð² 21:59, William L. Cleveland <wlc1(a)columbia.edu>: > I have been unsuccessful in using an Arduino board with Pharo 6.1(32bit) > and the Firmata package. > > > > The board is an Arduino Uno clone (ELEGOO UNO R3). The board appears to > work fine with the Arduino IDE, which was tested with the BLINK program. > The Standard Firmata Library appears to have been successfully uploaded to > the board using the Arduino IDE. > > > > COM ports have been closed using > > SerialPort allInstancesDo: [:port|port close]. > > On Windows 10, SerialPort inspect shows that ports are closed. However, > firmata := Firmata onPort: âCOM3â baudRate: 576000 failed due to failure to > open COM3. The serial port name was obtained from the Arduino IDE Tools > menu. The board choice was âArduino Unoâ. > > > > > > In MacOS 10.11.6, the same code generated a Cannot open comport message. > > > > Independently of Firmata, the following line of code SerialPort > allInstancesDo: [:port| port close] generated the following error message: > âInstance of BlockClosure did not understand #SerialPort. The same code > worked fine in Windows. > > > > I am wondering if the SerialPort code in Pharo6.1 is sufficiently robust > for a nonexpert programmer like myself, who only occasionally writes code > for his own use. Previously, I wrote an application for a robotics project > in 2008 using VisualWorks and the DLL&CConnect tool, which was quite > successful. No more coding until just recently, when I started using > Python. Would like to go back to Smalltalk if it is sufficiently robust. > > > > Any help would be appreciated. > > > Lou Cleveland >

Nov. 27, 2018

Re: [Pharo-users] how to write this without a if then

by Dale Henrichs

Roelof, One technique to eliminating the use of #ifTrue:ifFalse: is to use double dispatching. There are some good examples of using double dispatching in Ralph Johnson's paper "ARITHMETIC AND DOUBLE DISPATCHING IN SMALLTALK-80"[1].Â you should be able to get the basic idea by skimming the smalltalk code examples. I used double dispatching fairly extensively in Metacello ... In practice you may not eliminate all use of #ifTrue:ifFalse:, but double dispatching works quite well in places where you are tempted to do type checking... Dale [1] https://www.researchgate.net/publication/239578755_Arithmetic_and_double-_d… On 11/27/18 8:40 AM, Roelof Wobben wrote: > Hello, > > Yesterday I had a talk with luc frabresse about using if then. > He said if I understand it right, Its the best to not using a if then > or a ifTrue/ifFalse. > > Can anyone help me figure out how to rewrite this project so I will > not use the ifTrue in the basement function. > > my code so far can be found here : > https://github.com/RoelofWobben/AOC2015 > > Roelof > >

Nov. 27, 2018

Re: [Pharo-users] Pharo 7 - RFB

by Sanjay Minni

thanks all ----- cheers, Sanjay -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Nov. 27, 2018

how to write this without a if then

by Roelof Wobben

Hello, Yesterday I had a talk with luc frabresse about using if then. He said if I understand it right, Its the best to not using a if then or a ifTrue/ifFalse. Can anyone help me figure out how to rewrite this project so I will not use the ifTrue in the basement function. my code so far can be found here : https://github.com/RoelofWobben/AOC2015 Roelof

Nov. 27, 2018