March 2019 - Pharo-users - lists.pharo.org

Re: [Pharo-users] What's wrong with latest Pharo?

by john pfersich

What Linux (distro and version) and which version of Pharo. You couldnât supply less information if you tried. /*âââââââââââââââââ-*/ Sent from my iPhone https://boincstats.com/signature/-1/user/51616339056/sig.png See https://objectnets.net and https://objectnets.org > On Mar 31, 2019, at 14:21, Richard Kenneth Eng <horrido.hobbies(a)gmail.com> wrote: > > I just installed Pharo under Linux and when I start it up, I get: > > Error: External module not found > > It doesn't matter how I install Pharo.

March 31, 2019

What's wrong with latest Pharo?

by Richard Kenneth Eng

I just installed Pharo under Linux and when I start it up, I get: *Error: External module not found* It doesn't matter how I install Pharo.

March 31, 2019

Re: [Pharo-users] why is asDictonary a class method

by Roelof Wobben

March 31, 2019

Re: [Pharo-users] why is asDictonary a class method

by Tim Mackinnon

Hi Richard/all - thanks for helping Roelof out. Heâs working through the exercism.io exercises that weâve managed to convert so far. As they are based on more C like languages, they arenât always as OO as we want (once we get a decent set converted, weâll try and add some smallish examples - anyoneâs favourites appreciated). The dictionary reference is normally because the exercise tests like to assert on some description at the end (and dictionaries tend to exist universally in most languages). So view it more as a #printOn: like finalÃ© (this said - Roelof might have this behaviour in the wrong place - but we will see). The feedback so far, seems to have helpfully unblocked him so thanks all. Tim Sent from my iPhone > On 31 Mar 2019, at 12:02, Richard O'Keefe <raoknz(a)gmail.com> wrote: > > I think you probably need to show us *all* the code. > > directionLooking: aString > self new direction: aString > > Well, there is your problem. > There are two ways for a method to return a value. > One is to execute '^ e' for some expression e, > which is quite like a 'return e;' statement in C. > The other is to execute the whole body and come to > the end of the method, and in that case the result > is always 'self'. This means that the method as you > wrote it > - created an uninitialised or incompletely initialised > instance of Robot (self new) > - asked that instance to set its direction > - discarded the result of that setting > - forgot the new instance > - returned the Robot class > > What you probably meant was > directionLooking: aString > ^(self new) direction: aString; yourself > where 'yourself' has nothing to do with a new > object being created but with the fact that > you want the new object as the result, not > whatever #direction: returns. > directionLooking: aString > |newRobot| > newRobot := self new. > newRobot direction: aString. > ^newRobot > may be clearer to you. > > By the way, you didn't say WHY the caller wants a Dictionary > instead of a Robot. I don't think I've ever written a program > where that was a good idea. > > > > >> On Sun, 31 Mar 2019 at 19:55, Roelof Wobben <r.wobben(a)home.nl> wrote: >> Op 31-3-2019 om 03:47 schreef Richard O'Keefe: >>> Question 1. Should that be #asDictionary? >> >> >> yes, it does. >> >>> Question 2. If not, what's a Dictonary? >>> Question 3. I see you are using self-encapsulation, >>> with a getter 'self robot' >>> and a setter 'self robot: something'. >>> Of course that means that outside code >>> can freely smash your "robot" property, >>> unless #robot: checks that its argument >>> makes sense. Does it? >> >> >> no, it does not. >> >> >>> Question 4. What kind of thing *is* "robot". >>> Have you checked that 'Robot directionLooking: ...' >>> returns an instance of Robot? If you accidentally >>> omitted '^' it might return the Robot class itself. >> >> >> yes, I forget the ^ thing >> see this code. >> >> directionLooking: aString >> self new direction: aString >> >> >> so I have to think well how to return a instance of a Robot here. >> >> as far as I see I do not have a robot yet. >> >> createDirection: aString position: aCollection >> self robot: (Robot directionLooking: aString) yourself. >> ^ self robot asDictionary >> >> or I overlook something. >> >> >> >>> Question 5. Are you sure that 'self robot' returns >>> what you think it does? Have you checked? >> >> yes, I checked. self Robot give me a variable robot which is a Robot. >> >>> Question 6. Does Robot have an #asDictionary method? >>> Does Robot have an #asDictonary method? >> >> >> Yes, it does >>> Question 7. Why is "aCollection" not used in this method? >> >> Because I wanted to be sure things are working before I added the position which is a difficult one. >> >>> Question 8. Why are you using 'yourself'? >> >> I thought I was needed so I get a instance of a Robot back. >> >>> Question 9. Why does the caller want a dictionary instead of >>> a Robot? What should be in that dictionary? >>> >> >> The same data as the Robot has but then in a dictionary form. >> That is what I try to achieve. >> >>> There are more questions but those will do to be going on with. >>> If your #robot: method began like >>> robot: aRobot >>> (aRobot isKindOf: Robot) >>> ifFalse: [aRobot error: 'not an instance of Robot']. >>> you would have caught what I suspect is your problem. >>> Check question 4. >>> >>> >>> >>>> On Sun, 31 Mar 2019 at 07:19, Roelof Wobben <r.wobben(a)home.nl> wrote: >>>> Hello, >>>> >>>> Im busy with a new challenge from exercism. >>>> Where I have to keep track of a robot , where it facing and on that >>>> coordinate the robot is. >>>> >>>> so I made this function what the test wanted >>>> >>>> createDirection: aString position: aCollection >>>> self robot: (Robot directionLooking: aString) yourself. >>>> ^ self robot asDictonary >>>> >>>> I can see that on the first part a new robot is made with the right data. >>>> but the test wants the data back as a Dictonary >>>> that is why I made the self robot asDictonary line >>>> >>>> but to my suprise the compiler wants it be a class method where I expect >>>> it to be a instance method. >>>> >>>> Can someone explain to my why this is ? >>>> >>>> Roelof >>>> >>>> >>

March 31, 2019

Re: [Pharo-users] why is asDictonary a class method

by Richard O'Keefe

I think you probably need to show us *all* the code. directionLooking: aString self new direction: aString Well, there is your problem. There are two ways for a method to return a value. One is to execute '^ e' for some expression e, which is quite like a 'return e;' statement in C. The other is to execute the whole body and come to the end of the method, and in that case the result is always 'self'. This means that the method as you wrote it - created an uninitialised or incompletely initialised instance of Robot (self new) - asked that instance to set its direction - discarded the result of that setting - forgot the new instance - returned the Robot class What you probably meant was directionLooking: aString ^(self new) direction: aString; yourself where 'yourself' has nothing to do with a new object being created but with the fact that you want the new object as the result, not whatever #direction: returns. directionLooking: aString |newRobot| newRobot := self new. newRobot direction: aString. ^newRobot may be clearer to you. By the way, you didn't say WHY the caller wants a Dictionary instead of a Robot. I don't think I've ever written a program where that was a good idea. On Sun, 31 Mar 2019 at 19:55, Roelof Wobben <r.wobben(a)home.nl> wrote: > Op 31-3-2019 om 03:47 schreef Richard O'Keefe: > > Question 1. Should that be #asDictionary? > > > > yes, it does. > > Question 2. If not, what's a Dictonary? > Question 3. I see you are using self-encapsulation, > with a getter 'self robot' > and a setter 'self robot: something'. > Of course that means that outside code > can freely smash your "robot" property, > unless #robot: checks that its argument > makes sense. Does it? > > > > no, it does not. > > > Question 4. What kind of thing *is* "robot". > Have you checked that 'Robot directionLooking: ...' > returns an instance of Robot? If you accidentally > omitted '^' it might return the Robot class itself. > > > > yes, I forget the ^ thing > see this code. > > directionLooking: aString > self new direction: aString > > > so I have to think well how to return a instance of a Robot here. > > as far as I see I do not have a robot yet. > > createDirection: aString position: aCollection > self robot: (Robot directionLooking: aString) yourself. > ^ self robot asDictionary > > or I overlook something. > > > > Question 5. Are you sure that 'self robot' returns > what you think it does? Have you checked? > > > yes, I checked. self Robot give me a variable robot which is a Robot. > > Question 6. Does Robot have an #asDictionary method? > Does Robot have an #asDictonary method? > > > > Yes, it does > > Question 7. Why is "aCollection" not used in this method? > > > Because I wanted to be sure things are working before I added the > position which is a difficult one. > > Question 8. Why are you using 'yourself'? > > > I thought I was needed so I get a instance of a Robot back. > > Question 9. Why does the caller want a dictionary instead of > a Robot? What should be in that dictionary? > > > The same data as the Robot has but then in a dictionary form. > That is what I try to achieve. > > There are more questions but those will do to be going on with. > If your #robot: method began like > robot: aRobot > (aRobot isKindOf: Robot) > ifFalse: [aRobot error: 'not an instance of Robot']. > you would have caught what I suspect is your problem. > Check question 4. > > > > On Sun, 31 Mar 2019 at 07:19, Roelof Wobben <r.wobben(a)home.nl> wrote: > >> Hello, >> >> Im busy with a new challenge from exercism. >> Where I have to keep track of a robot , where it facing and on that >> coordinate the robot is. >> >> so I made this function what the test wanted >> >> createDirection: aString position: aCollection >> self robot: (Robot directionLooking: aString) yourself. >> ^ self robot asDictonary >> >> I can see that on the first part a new robot is made with the right data. >> but the test wants the data back as a Dictonary >> that is why I made the self robot asDictonary line >> >> but to my suprise the compiler wants it be a class method where I expect >> it to be a instance method. >> >> Can someone explain to my why this is ? >> >> Roelof >> >> >> >

March 31, 2019

Re: [Pharo-users] why is asDictonary a class method

by Roelof Wobben

March 31, 2019

Re: [Pharo-users] why is asDictonary a class method

by Richard O'Keefe

Question 1. Should that be #asDictionary? Question 2. If not, what's a Dictonary? Question 3. I see you are using self-encapsulation, with a getter 'self robot' and a setter 'self robot: something'. Of course that means that outside code can freely smash your "robot" property, unless #robot: checks that its argument makes sense. Does it? Question 4. What kind of thing *is* "robot". Have you checked that 'Robot directionLooking: ...' returns an instance of Robot? If you accidentally omitted '^' it might return the Robot class itself. Question 5. Are you sure that 'self robot' returns what you think it does? Have you checked? Question 6. Does Robot have an #asDictionary method? Does Robot have an #asDictonary method? Question 7. Why is "aCollection" not used in this method? Question 8. Why are you using 'yourself'? Question 9. Why does the caller want a dictionary instead of a Robot? What should be in that dictionary? There are more questions but those will do to be going on with. If your #robot: method began like robot: aRobot (aRobot isKindOf: Robot) ifFalse: [aRobot error: 'not an instance of Robot']. you would have caught what I suspect is your problem. Check question 4. On Sun, 31 Mar 2019 at 07:19, Roelof Wobben <r.wobben(a)home.nl> wrote: > Hello, > > Im busy with a new challenge from exercism. > Where I have to keep track of a robot , where it facing and on that > coordinate the robot is. > > so I made this function what the test wanted > > createDirection: aString position: aCollection > self robot: (Robot directionLooking: aString) yourself. > ^ self robot asDictonary > > I can see that on the first part a new robot is made with the right data. > but the test wants the data back as a Dictonary > that is why I made the self robot asDictonary line > > but to my suprise the compiler wants it be a class method where I expect > it to be a instance method. > > Can someone explain to my why this is ? > > Roelof > > >

March 31, 2019

Re: [Pharo-users] How to generically find methods in class hierarchies? (Aka narrow spotter?)

by Ben Coman

On Sat, 30 Mar 2019 at 20:25, Tim Mackinnon <tim(a)testit.works> wrote: > You - know, this has made me realise that I donât understand the > difference between #messages and #implementors in Spotter? In my haste Iâve > always jumped on the latter (as its first in the spotter list) - and > implementors has much more methods. So thats a good tip. > > In realising this now, Iâm wondering how you easily jump down the sections > with the keyboard on OSX - help says cmd-shift-down but it appears to not > work (maybe a regression?). > Try... wrap #m but that is a bit insider knowledge and easy to miss. Perhaps showing this shortcut in the heading would help... "#Messages (#m) nnn/NNN" I took a poke at doing that, browsing senders of #spotterOrder: I found... CompiledMethod>>spotterForMessagesFor: aStep <spotterOrder: 12> aStep listProcessor title: 'Messages'; allCandidates: [ self messages asSortedCollection collect: [:each | GTSelector new name: each ] ]; filter: GTFilterSubstring But as a test changing the title to 'Messages x' is not reflected when I next open Spotter. Any clues where the "#Messages (#m) nnn/NNN" would be made? cheers -ben

March 31, 2019

Re: [Pharo-users] why is asDictonary a class method

by Dennis Schetinin

Didn't you forget to return (^) an instance from #directionLooking:? And why do you need to send #yourself? ÑÐ±, 30 Ð¼Ð°ÑÑÐ° 2019 Ð³. Ð² 21:19, Roelof Wobben <r.wobben(a)home.nl>: > Hello, > > Im busy with a new challenge from exercism. > Where I have to keep track of a robot , where it facing and on that > coordinate the robot is. > > so I made this function what the test wanted > > createDirection: aString position: aCollection > self robot: (Robot directionLooking: aString) yourself. > ^ self robot asDictonary > > I can see that on the first part a new robot is made with the right data. > but the test wants the data back as a Dictonary > that is why I made the self robot asDictonary line > > but to my suprise the compiler wants it be a class method where I expect > it to be a instance method. > > Can someone explain to my why this is ? > > Roelof > > > -- -- Best regards, Dennis Schetinin

March 30, 2019

why is asDictonary a class method

by Roelof Wobben

Hello, Im busy with a new challenge from exercism. Where I have to keep track of a robot , where it facing and on that coordinate the robot is. so I made this function what the test wanted createDirection: aString position: aCollection Â Â Â self robot: (Robot directionLooking: aString) yourself. Â Â Â ^ self robot asDictonary I can see that on the first part a new robot is made with the right data. but the test wants the data back as a Dictonary that is why I made the self robot asDictonary line but to my suprise the compiler wants it be a class method where I expect it to be a instance method. Can someone explain to my why this is ? Roelof

March 30, 2019