Beginners May 2016

beginners@lists.squeakfoundation.org

24 participants
13 discussions

New Introductory Tutorial
by EuanM 26 Aug '16

26 Aug '16

I've created Yet Another Smalltalk First Steps tutorial. This is intended as one of a series. It is designed to be cross-platform across Squeak 5 Pharo 4 Seaside 3.1 Cuis Dolphin 6 If you have experience running any of these systems on Windows, Linux or MacOS, please check to see if I have the instructions correct for your chosen pairing of Smalltalk and OS platform. (As you'll see when you look, I do not have detailed instructions for aspects of MacOS). The document is at: http://smalltalkinsmallsteps.blogspot.co.uk/2015/11/get-smalltalk-up-and-ru… (It's intended to move to a different blog after this review process). I feel the need to do this as cross-Smalltalks tutorial because of findings and 4 charts I've placed at: http://smalltalkinsmallsteps.blogspot.co.uk/2015/11/mindshare-of-smalltalk-… Essentially, Smalltalk mindshare and use is incredibly tiny, compared to other languages in the same space. (We all know this, but seeing it represented graphically has a more visceral effect, IMO) Aggregating interest in all the Smalltalks still does not bring more than a tiny proportion of the interest in, and use of, Ruby. In turn, Ruby is (quite understandably) small in comparison to JavaScript. Comparing interest in any specific Smalltalk is, predictably, smaller than the aggregate interest in Smalltalk. Our community seems determined to split itself into smaller and smaller sub-communities. I think we do ourselves a disservice this way. My initial contribution will be to try to provide some explicitly pan-Smalltalk beginners' tutorials, like this one. Cheers, and happy Smalltalking, EuanM

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FileDirectory
by Joseph Alotta 01 Jun '16

01 Jun '16

Greetings, I am looking for some documentation or snippets of code for using the FileDirectory class. I want to check if a file exists before I try to read it. I also want to look at a list of files in the directory. I did search SBE and google but found nothing. Sincerely, Joe.

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size of character
by Joseph Alotta 23 May '16

23 May '16

‘j’ size ==> 1 $j size ==> error. Why shouldn’t the size of a character be 1? Sincerely, Joe.

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help with morphic
by Joseph Alotta 20 May '16

20 May '16

Greetings, I am having trouble getting started with Morphic. I tried the tutorial on squeak.org and found it too hard to follow. Now I have morphs on my screen and I don’t know how to close them. I looked for videos on Morphic and found only a technical comparison of changes. Is there a video designed for beginners that someone not an egghead can follow? Sincerely, Joe.

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whats the difference between over and through
by Joseph Alotta 18 May '16

18 May '16

Greetings, What’s the difference between over and through in the debugger? Is there something that goes to the next line of code? Sincerely, Joe.

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Re: Need a local tutor for Squeak
by Joseph Alotta 17 May '16

17 May '16

It would be very hard to compete with meetup. They have a moat because they were first. I run a meetup group and I have 1000 members, just because they are on meetup and not somewhere else. Same thing for eBay. Everyone hates it. But it is where the buyers and the sellers are. Sincerely, Joe. > On May 16, 2016, at 12:39 AM, askoh [via Smalltalk] <ml-node+s1294792n4895074h43(a)n4.nabble.com> wrote: > > Ron: > > Have you thought about a virtual equivalent to meetup.com? Is there something available already? > > All the best, > Aik-Siong Koh > > If you reply to this email, your message will be added to the discussion below: > http://forum.world.st/Need-a-local-tutor-for-Squeak-tp4888503p4895074.html > To start a new topic under Squeak - Beginners, email ml-node+s1294792n107673h12(a)n4.nabble.com > To unsubscribe from Squeak - Beginners, click here. > NAML -- View this message in context: http://forum.world.st/Need-a-local-tutor-for-Squeak-tp4888503p4895149.html Sent from the Squeak - Beginners mailing list archive at Nabble.com.

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Machine gun the Balloon!
by Kirk Fraser 16 May '16

16 May '16

Byte magazine which published the balloon concept for Smalltalk rising above the ivory tower of a lighthouse guiding the way in a sea of computer languages is out of business. I think it is time for the Squeak balloon to be grounded to connect with the reality of why computer languages exist - to make things easy for application developers. So I propose all Squeak developers stop "improving" Squeak for one year and spend the time writing useful applications in Squeak. That could lead to a basket of new ideas for next year. Maybe make this a regularly scheduled event - a half year for applications and a half year for Squeak? The reason motivating this suggestion is on the advice of a Squeak-Dev member, I downloaded the latest all in one and to my chagrin, I found an improvement that made Squeak as worthless as a balloon full of machine gun holes. The Workspace window gets halos with a right mouse click on a standard 2 button laptop mouse. So I'll return to an older Squeak for now.

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Need a local tutor for Squeak
by Joseph Alotta 14 May '16

14 May '16

I need a local person to help me with Squeak Smalltalk. I like in the Western suburbs of Chicago, in Downers Grove. I want someone to show me all the things I am missing and to help me use the tools more effectively. I am thinking we could meet at a coffee shop once a week for an hour. I would pay for each lesson, $70. Sincerely, Joe Alotta joseph.alotta(a)gmail.com -- View this message in context: http://forum.world.st/Need-a-local-tutor-for-Squeak-tp4888503.html Sent from the Squeak - Beginners mailing list archive at Nabble.com.

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'1921' romanNumber
by Joseph Alotta 13 May '16

13 May '16

Shouldn’t this work? '1921’ romanNumber I get an error index out of bounds. Sincerely, Joe.

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Sharing a Singleton for read-only access to data
by Tim Johnson 13 May '16

13 May '16

Hello Squeakers, It is cool that we have this forum for asking these kinds of questions. -- TL;DR -- I learned I probably shouldn't subclass a singleton even though it seemed so easy; I wonder instead how to design my controller properly in an MVC paradigm; should I learn about Factory methods and add them to my singleton?; should I keep query methods out of my data-holding Singletons and move them to new Presenter objects as intermediaries between data-holding Singletons and views?; should I read a book?; should I give up and go home?. -- THE TASK -- I am working on a little Seaside app for my job, with a maximum of ~4 simultaneous users. It started as skunkworks but has proved kind of useful. My model has a couple of singletons for a couple of collections of data represented as (say) MyRecords or XYZRecords. Singletons seemed good because the source materials being parsed into these records are ~4.0 MB apiece, so I don't want multiple copies of the data hanging around, and I only need read-only access. Maybe the singletons could be described like this: #MyReader class "Singleton; Reads some CSV or other formats; parses into MyRecords; makes collections of MyRecords available using different query methods" For a quick-and-dirty solution to get a demo up-and-running to show my boss, I subclassed one of my Singletons (oh no!) as FilteredMyReader and added #filterByYear:, #filterBlock:, and #resetFilter methods. Inside this subclass, I just overrode the accessor for the XYZRecords to something like this: #records ^ records select: (self filterBlock) with some helper methods: #filterByYear: aYear self filterBlock: [:ea | ea year = aYear] ... and #resetFilter ... self filterBlock: [:ea | true ] With these new methods in my subclass, I had a drop-in replacement for my MyReader. It worked great! All of my query-style and-reporting-style methods were still available (because it is a subclass), but because the accessor method now was filtered, they showed only the data I wanted. Woo-hoo! -- BUT THERE CAME TO BE A PROBLEM -- the big problem arose when multiple sessions (multiple users) were accessing the app at the same time. Seasoned Smalltalk vets are sure to chuckle to themselves now, but I am not exactly sure why this happened (subclassing singletons is not threadsafe?). I think when one session would change the filterBlock, it would affect another session's view into the data. So one user may be intending to view 2016 but it may actually show 2012. (When designing this quick-and-dirty solution, I may have mistakenly thought that each Session had a new instance of my new FilteredMyReader subclass, but probably not [!], because it was a subclass of a singleton [!]). So, I have reached the philosophical point where I get to ask "is this is a bug in my implementation, or a flaw in my design?" A quick Google of "subclass a singleton" brings up a number of results akin to "don't do this, but if you have to, here's how: " so I think my quick-and-dirty solution might be at fault. -- SO -- as I ponder whether the flaw is in my implementation or my design, I question whether the proper approach and a working solution would be to stop subclassing the Singleton and instead do one of the following: 1) In the Singleton, keep my query/reporting methods, but instead of returning Bags or OrderedCollections or what-have-you, have them manufacture (like a Factory?) instances of a to-be-created class of object which would be like a 'looking glass' into the data, like an intermediary between the Seaside component and the model. Not sure what the terminology would be -- Presenter? Controller? I think "Art and Science of Smalltalk" (Simon Lewis) might have called it a Presenter or a PluggableSomething. 2) Similar to (1) but skip any interaction between the Singleton and the View/Session altogether. Create a new XYZPresenter or Controller or PluggableSomething class which can have many instances around, without holding copies of the Singleton's data. Create these on-demand from my WASession subclass (controller) or in my components (view). These new objects will interact with the Singleton themselves in a read-only fashion. 3) Give up on Singletons for holding data and keep this stuff in a database outside of the image. My coworkers want a traditional relational database anyway. After writing all of this up, I am still a bit confused how to proceed, because the HPI Seaside tutorial I read many years ago says a WASession subclass is supposed to be my "Controller." So maybe I should leverage /it/ more to access the singletons / model (without storing copies of the data!). But maybe I still would be best served by creating an additional intermediary between my WASession subclass (as controller) and the Singletons (as /part/ of the model). I hope this wasn't too much to follow, and might prove fun and instructive for someone. (Please note that while I may make references to what may be some Design Patterns, I haven't fully read the books or the Smalltalk companion, so I am speaking only with some infantile understanding of what I am talking about.) Thanks, Tim

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Beginners May 2016