July 2017 - Pharo-users - lists.pharo.org

Question
by Koos Brandt July 24, 2017

July 24, 2017

Hi I am still learning but something weird happened. In a new Workspace Do-it myVar := LargeInteger new Print-it myVar <error in printString: try 'Inspect it' to debug> When I inspect it I get SubclassResponsibility: LargeInteger had the subclass responsibility to implement #printOn:base: When I browse LargeInteger, then at Integer level I get a message ânewâ as follows: new self == Integer ifTrue: [ ^ self error: 'Integer is an abstract class. Make a concrete subclass.']. ^ super new I looked for new higher up in the hierarchy(super), but could not see it. Maybe I am a bit dumb still with looking up. I tried on SmallInteger a new, but got back Error: SmallIntegers can only be created by performing arithmetic. I then checked and noticed that SmallInteger actually have new and basicNew implemented (override) So the error I got on smallinteger was from the override LargeInteger has no override, but has a âsilent" error This seems a bit weird to me Just so you know I also tried Do-it myVar := LargeInteger new: 10000 Print-it myVar class. -> LargeInteger Dot-it myVar := myVar + 1 The last statement hangs the image! (Tried 3 times) Comment: 1. I am surprised that Do-it did not give me an error on the new: (there is a message is the hierarchy of new:neg and maybe the neg is optional?) 2. The new: seemed to have created 10000 LargeIntegers 3. I tried the new: also with just 5, and same result, image hang. (I thought 10,000 was maybe a very large loop for the + 1..) Did I damage something in the image maybe? I started this one just yesterday to look at MOOC week1. I do not need LargeIntegers for now but â¦ This is Pharo 6.0 64 Bit on Mac OSX Sierra 10.12.5 (iMac 27, 2.9GHz Intel Core i5, 16GB RAM) Regards Koos Brandt 0824542028

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Why do we separate class/instance methods in the browser?
by Tim Mackinnon July 24, 2017

July 24, 2017

Hi - this week I was asked to run a mob programming session with Smalltalk - and show a group of experienced developers Smalltalk so that they could practice mobbing around a new idea. It worked really well, a 20 min talk explaining a bit of the ethos and a few key features and some quick syntax and they were able to charge ahead and really enjoy themselves. It was interesting however to see what things confused them the most (and also what things impressed them - there were many). The one that stuck out for me (and is actually mentioned in another thread this week) was the class/instance method difference. They conceptually understood the difference coming from other languages but our UI is tricky to understand with the Class button toggle we have, and if you get methods on the wrong side, like with a test, it's quite confusing. Anyway - this got me thinking - why do we bother having a toggle in our UI for this these days? Of course we know there is a class and a metaclass but given that we have icons for methods now (and also have a Protocol pane ) why don't we just show all the methods we have in one list and let you filter them or even see them all? It seems much easier and way more efficient to rapidly code this way. The only question then would be how to create methods of the right type - whether to have a button to create the right template (and put the browser code pane in the right context) or whether to indicate it by convention of the method name when creating it like + new: aSize etc. (Or even: class new: aSize etc). The more I think about it, the more it seems like something we should consider trying both for making ourselves more efficient (I'll bet everyone has written a method on the wrong side by mistake) and also helping newcomers. I'll bet it's quite easy to do in Calypso as well if I've understood Denis' model story properly. Has this been tried before? Is it heretical? Tim Sent from my iPhone

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Pharo 6, scrolling with 2 fingers on a Mac trackpad is very erratic
by Tim Mackinnon July 23, 2017

July 23, 2017

Hi - Iâm wondering if anyone else has noticed that in Pharo 6, when you scroll on a MacBook trackpad with 2 fingers, that strange things happen, particularly if you do it quickly. For example, in a system browser if you expand the configurations tree and scroll through it, it very often just suddenly closes that tree and just selects the âLast Modified Methodsâ and âConfigurationsâ list items. OR it will keep jumping to the top of the list and start scrolling down again. I see this latter behaviour when scrolling through methods of a class as well. I havenât noticed it in other applications, and its possible its my laptop or maybe settings I have on it - but Iâm curious if others have seen the same behaviour? I will go back and check a Pharo 3 or 5 image and see if its the same back there. Tim

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What is the setting Software Configuration Management | Default Local Repository and why does it have a strange value?
by Tim Mackinnon July 23, 2017

July 23, 2017

Hi - A while back I was struggling with loading some metacello libraries and was convinced there was something wrong with the default working directory. I found a different way of loading things and moved on. Anyway - I have just noticed in the the settings Browser that there is a section Software Configuration Management | Default Local Repository directory and it has a strange value in it that I didnât set and all my ZeroConf images seem to be using it (/builds/workspace/Pharo-6.0-Update-Step-1-Tracker). I âm wondering if this is a bug, or some artefact of how the images are being built - and maybe it was the cause of why Monticello was reporting weird directories? Equally there is another setting below it - Local Cache directory, and it seems to default to another strange directory (an old image of mine) - again I didnât set this in newer zero conf images - and Iâm wondering how that value gets in there are well (is there some global settings file my images automatically read?) Tim

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Is it possible to change the Pharo application title bar?
by Tim Mackinnon July 23, 2017

July 23, 2017

Hi - is it possible to easily change the Pharo.image title bar in the pharo application? (As in the OSX title bar, or Windows one). I find that I often have multiple images running and its difficult to distinguish them - so having a title that had the immediate path of the image would be very useful. Iâd prefer not to have to rename image files (althoughI guess could if its not easy to change the title). Tim

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NeoCSV change proposal
by Peter Uhnak July 23, 2017

July 23, 2017

Hi, this is a continuation of an older thread about quoting fields only when necessary. ( http://forum.world.st/NeoCSVWriter-automatic-quotes-td4924781.html ) I've attached fileouts of NeoCSV packages with the addition (I don't know if Metacello can file-out only changesets). The change doesn't affect the default behavior, only when explicitly requested. Peter

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"Leak"/reference hunting with RefsHunter
by Holger Freyther July 22, 2017

July 22, 2017

Hi, as I didn't remember the name of the tool and maybe as future reference to myself. I have installed RefsHunter from the catalogue and it helped me a lot. I was looking at the memory consumption of my Pharo6.0 image and did something crazy like counting how many objects exist of a specific class (Object allSubInstances copy do.. and put that into a dictionary). I noticed that for the ASN1 model the nodes of the parse tree survived. Yesterday I tried to use the pointer explorer but then most references are held by the UI code and I gave up after a bit. Today I found the RefsHunter again and something as simple (found through the class comments) | rh | rh := RefsHunter snapshot. rh wayFrom: ASN1AssignmentNode allInstances first to: myAsn1Model Brings me to a list of references and when searching the list from the end to the beginning gives a pretty good picture of where things go wrong. Great to have a platform that allows to walk the heap and great that there are tools that make it manageable! have a nice weekend holger

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Pharo MOOC: Difference between class methods and instance methods
by Michel Marinier July 22, 2017

July 22, 2017

I am an absolute beginner at Pharo and IÂm working my way through Pharo by Example as well as the MOOC online. While coding the TinyBlog example in the MOOC, I got stuck until I kind of ÂguessedÂ the difference between ÂTBPost >> methodNameÂ and ÂTBPost class >> methodNameÂ. I didnÂt know I had to click on the Class button to access the class methods and coded all the methods as instance methods. As a result, the system complained when the code tried create a new instance from a method such as Âtitle: text:Â. I suppose I might have missed the place where this was explained in the MOOC, although IÂm not sure it was emphasized early on in the lessons. However, a suggestion would be that if you ever update the exercises that a notice be added warning students of the difference, at least in the first few exercises where there is so much to learn and remember. IÂm doing it in French, so it might look like this: Â NÂoubliez pas la diffÃ©rence entre ÂTBPost >>Â et ÂTBPost class >>Â. Le premier indique quÂil sÂagit dÂune mÃ©thode dÂinstance. Le second indique quÂil sÂagit dÂune mÃ©thode de classe. Vous devez cliquer le bouton ÂClassÂ pour accÃ©der Ã la section correspondante. Dans la section pour lÂinstance, la dÃ©finition dÃ©bute par ÂObject subclass: #TBPostÂ alors que dans la section pour la classe, la dÃ©finition dÃ©bute par ÂTBPost classÂ. Â By the way, congrats on the great work providing those resources. I love the advice to poke around the system with the Browser and the Finder to find out stuff. Thanks.

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Playground and Dr. Geo
by Hilaire July 22, 2017

July 22, 2017

Hi, I am integrating the Dr. Geo Smalltalk Sketch to Playground. So far, Dr. Geo morphic view is well integrated and interactive is there. However when I select a menu in the view it opens deported. See attached screenshot. The Dr. Geo view is a StandardWindow with its label area hidden. Any idea? Thanks Hilaire -- Dr. Geo http://drgeo.eu

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best naming practices for (file) format reading/writing
by Peter Uhnak July 22, 2017

July 22, 2017

Hi, I've seen (and I use) different naming conventions when reading/writing from files/streams... e.g. MyReader new readFromStream: aStream. "-> aModel" MyWriter new writeToStream: aModel. "-> aStream" or (MyReader new on: aStream) upToEnd. "-> aModel" (MyWriter new on: aStream) nextPut: aModel. "-> aStream" or MyReader new fromString: aString. "-> aModel" MyReader new toString: aModel. "-> aString" etc. (optionally with class-side methods for convenience). Do we have some best practices/recommendations/conventions regarding this? Thanks, Peter

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