June 2021 - Pharo-users - lists.pharo.org

UK Smalltalk User Group meeting - Wednesday June 30th
by Giovanni Corriga June 23, 2021

June 23, 2021

The next meeting of the UK Smalltalk User Group will be on Wednesday, June 30th. Hernan Wilkinson ( https://twitter.com/HernanWilkinson ) will talk about his LiveTyping project. Currently, almost all mainstream dynamically typed languages support type annotation a la Strongtalk. Python calls it "type hints", TypeScript is JavaScript+type annotations, PHP calls it "type declarations" and Ruby does it through a tool called Sorbet. All of them annotate the types in the source code and it is the programmer who must write and maintain the annotation. In all cases, it is not mandatory for the system to correctly type check for it to run. LiveTyping ( https://github.com/hernanwilkinson/LiveTyping ) is a type system proposal for Smalltalk, that seeks similar objectives but implemented in a different way. First, it is the environment itself that collects and maintains the types based on the execution of the system, not the programmer. Second, the types are not interleaved in the source code, thus maintaining the syntax and simplicity of the language. And finally, the main objective is not to carry out a static type checking (although it supports it), but to augment the programmers experience increasing the usability of current tools such as searching for senders and implementers, and performing more accurate and safe refactorings. In this talk Hernan will briefly show how LiveTyping is implemented to later concentrate on the improvements made to the tools and the benefits it brings when developing software with Smalltalk. LiveTyping is currently implemented in Cuis Smalltalk ( https://cuis-smalltalk.org/ ) and has been successfully used for the last two years in three different universities in Argentina when teaching Object Oriented Programming and Design. Given the current COVID-19 restrictions, this will be an online meeting from home. If you'd like to join us, please sign up in advance on the meeting's Meetup page ( https://www.meetup.com/UKSTUG/events/cbklbryccjbfc/ ) to receive the meeting details. Donât forget to bring your laptop and drinks!

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Re: Implementing DataFrame>>dtypes feature in Pharo PolyMath Project
by Balaji G June 19, 2021

June 19, 2021

Thank you sir for the clarification. On Sat, Jun 19, 2021 at 7:24 PM Konrad Hinsen <konrad.hinsen(a)cnrs.fr> wrote: > Dear Balaji, > > > I am working on implementing the DataFrame>>dtypes feature which > > checks the datatypes of columns in a DataFrame, as part of my GSOC > > project. I have tried to explain my theoretical work done so far on > > this blog post. Please kindly go through it , as I need advice on what > > could be the optimal way to implement this feature. Any kind of input > > and discussions is most welcome. > > Your post looks like an overall accurate description of the current > state of everything - with one exception, and that is Pandas. You say > you didn't look at the Pandas code yet, so that's not surprising. > > You seem to assume that Pandas stores Python objects as elements of > DataFrames, but that isn't true. Pandas uses NumPy arrays instead. And > NumPy arrays are very different from standard Python objects, because > their internal data layout is by design the same as used in C or > Fortran. For a full description, see > > https://numpy.org/doc/stable/user/basics.rec.html > > However, I am not sure you need to understand this in all detail, as I > am pretty sure that you do not want to copy this approach in Pharo. > > The one point that does matter for you is where NumPy and Pandas take a > column's dtype from. The answer is that it's defined when a DataFrame is > created, and it cannot be changed afterwards. If a column is "integer", > it will remain "integer" forever. If you try to assign a string to an > element of such a column, you get an error message. When you create a > DataFrame from existing data, e.g. by reading a CSV file, Pandas scans > the data and determines a suitable dtype, much in the same way as V1.0 > in Pharo/PolyMath did. But since Pandas doesn't allow any later change, > there is no serious performance issue. > > So that's an option you can add to your list: define the dtypes once and > for all when the DataFrame is created. The main drawback is that you > would have to change the API for DataFrame creation to make this work. > > Cheers, > Konrad > -- > --------------------------------------------------------------------- > Konrad Hinsen > Centre de Biophysique MolÃ©culaire, CNRS OrlÃ©ans > Synchrotron Soleil - Division ExpÃ©riences > Saint Aubin - BP 48 > 91192 Gif sur Yvette Cedex, France > Tel. +33-1 69 35 97 15 > E-Mail: konrad DOT hinsen AT cnrs DOT fr > http://dirac.cnrs-orleans.fr/~hinsen/ > ORCID: https://orcid.org/0000-0003-0330-9428 > Twitter: @khinsen > --------------------------------------------------------------------- >

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Implementing DataFrame>>dtypes feature in Pharo PolyMath Project
by Balaji G June 19, 2021

June 19, 2021

Hi I am working on implementing the DataFrame>>dtypes feature which checks the datatypes of columns in a DataFrame, as part of my GSOC project. I have tried to explain my theoretical work done so far on this blog post. Please kindly go through it , as I need advice on what could be the optimal way to implement this feature. Any kind of input and discussions is most welcome. Link to the post : Background work on DataFrame dtypes <https://balaji612141526.wordpress.com/2021/06/19/background-work-on-datafra…> Thank you Balaji G

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[ANN] Camp Smalltalk Supreme Finalized!
by Richard Kenneth Eng June 18, 2021

June 18, 2021

As of today, Wednesday, June 17, 2021, I have successfully nailed down the most exciting roster of keynote speakers for *Camp Smalltalk Supreme* next year. Here they are: 1. *Adele Goldberg* â co-creator of Smalltalk 2. *Dan Ingalls* â co-creator of Smalltalk 3. *Kent Beck* â Smalltalk pioneer 4. *David Buck* â Smalltalk veteran and podcaster This will be the greatest programming language birthday bash ever. As I wrote to Dan Ingalls... "I checked birthday celebrations for other languages like FORTRAN, LISP, COBOL, BASIC, and Pascal, and they were quite anemic." For more information, visit: https://gofund.me/225341e3 I invite presenters to register. Cheers, Richard

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Zn and AWS - retrieving object versions?
by Tim Mackinnon June 18, 2021

June 18, 2021

Hi everyone - Iâm wondering if someone knows the trick to listing object versions in AWS S3? I was previously using a non-Zn library (there are a few around - but they are quite old and Iâm not sure how much they are maintained) - however I hadnât realised that Zn actually supports S3 until I read it a bit carefully and realised that I needed to load an extra AWS group. So - I have a bucket that is versioned, and I wanted to read the versions of an object - and hopefully be able to read the contents of an older version. I can list the contents of a bucket, but when I try to read the versions of an object - I get a forbidden error - which when I dig deeper gives a stranger explanation? I have confirmed that the AWS CLI is able to list versions in that bucket - so Iâm a bit confused what the issue might be? (client := ZnAWSS3Client new) accessKeyId: 'xxx'; secretAccessKey: âyyyyy'; checkIntegrity: true. client buckets. âWorks" client keysIn: 'mtt-dataâ. âWorks" client at: 'mtt-data' -> 'sample.txtâ. âWorks" client keysIn: 'mtt-data' query: (Dictionary with: 'versions'->nil). âGives an error?â HTTP/1.1 403 Forbidden <?xml version="1.0" encoding="UTF-8"?> <Error><Code>SignatureDoesNotMatch</Code><Message>The request signature we calculated does not match the signature you provided. Check your key and signing method.</Message><AWSAccessKeyId>xxx</AWSAccessKeyId><StringToSign>GET Has anyone tried doing this - Iâm sure there is something really simple that I am missing? Tim

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Spec Gtk Applications - Implementing File open/save/(print?) dialogs
by kmo June 17, 2021

June 17, 2021

Hi - When writing a Gtk app using Pharo Spec2 are there any facilities for standard system dialogs - open file / save file / etc - or do you have to create them from scratch yourself (perhaps using SpDialogPresenter) ? Thanks in advance for any clarification. Ken -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

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Reading http post data using Zinc
by Davide Varvello June 17, 2021

June 17, 2021

Hi Guys, I'm posting from an http form and I'm wondering how to read data from the post. It seems the request should give a ZnMultiPartFormDataEntity, but I can't find how to use it. Can you help me please? Davide -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

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Rounding in Floats
by Esteban Maringolo June 17, 2021

June 17, 2021

Hi, Continuing with my issues with decimals, I'm having one issue that is not clear to me why it happens. If I do: (9.1 + (-2.0)) roundTo: 0.1. "7.1000000000000005" I expect to get a single decimal Float (rounded with whatever precision, but a single decimal). Even if I do something like this: 7.1 roundTo: 0.1 It gives the wrong result. In VW and VAST it provides the right result. (9.1 + (-2.0)) roundTo: 0.1 "7.1" In Dolphin it also returns the wrong result, it seems to use the same algorithm to round it. Is this a bug? Esteban A. Maringolo

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Problem installing 9.0 on MacMini M1
by David Pennington June 16, 2021

June 16, 2021

Hi everyone. It is your favourite newbie speaking :-) I have now got a new M1 MacMini which I want to configure up as a server for my Seaside apps. So far, I have found that the Mac mini doesnât have wget or brew installed! I have sorted wget but not brew. Secondly, I have transferred all of my 9.0 stuff across but when I try and execute both paharo-ui or pharo (as terminal scripts) they both fail as they say that the âPaharoâ is damaged and canât be opened. You should move it to the bin. I can open Pharo 9.0 directly but it tells me that the VM is too old for this image. Can anyone help me please? (In words that I can understand:-) David

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How to get dimensions (extent) of a SpPresenter
by kmo June 16, 2021

June 16, 2021

I'm porting a little Morphic geometry program from Morphic to a Spec 2 application using GTK. I need to draw a shape in an SpAthensPresenter but to draw it I need to know the current dimensions (extent) of the presenter so it can still work OK even when the window is resized. The old Morphic version also used An Athens canvas but I had no problem then as a morph has an extent method that provides this information. But now that I can't use a morph I find that the extent method of an SpPresenter always seems to answer nil. Is that right? How d you get the current size of a presenter? Is it a bug? I'm using a very recent Pharo 9 image and headless VM on Linux. Image ----- /home/kmp/Pharo/images/gtkRoses/gtkRoses.image Pharo9.0.0 Build information: Pharo-9.0.0+build.1399.sha.9ae8329dedfbad7915b7b2cdc4accc7ce8109ce0 (64 Bit) Unnamed Virtual Machine --------------- /home/kmp/Pharo/vms/90-x64-headless/lib/pharo CoInterpreter VMMaker-tonel.1 uuid: 286e9806-8e7d-0d00-ab06-4e280faf8631 Apr 30 2021 StackToRegisterMappingCogit VMMaker-tonel.1 uuid: 286e9806-8e7d-0d00-ab06-4e280faf8631 Apr 30 2021 5125110 - Commit: 5125110 - Date: 2021-04-30 10:05:04 +0200 Pharo 9.0.0 built on Apr 30 2021 10:22:47 Compiler: 5.4.0 20160609 VMMaker versionString 5125110 - Commit: 5125110 - Date: 2021-04-30 10:05:04 +0200 CoInterpreter VMMaker-tonel.1 uuid: 286e9806-8e7d-0d00-ab06-4e280faf8631 Apr 30 2021 StackToRegisterMappingCogit VMMaker-tonel.1 uuid: 286e9806-8e7d-0d00-ab06-4e280faf8631 Apr 30 2021 Any help woudl be appreciated. -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

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