March 2022 - Pharo-users - lists.pharo.org

ByteString asDate
by Robert Briggs March 4, 2022

March 4, 2022

I may be being stupid but the current Date Class does not appear to protect itself against a ByteString that is not in valid date format, e.g. by raising an Error. e.g. the code Â âABCâ asDate opens the Debugger on #isLetter was sent to nil because it appears to expect more letters after $C but the peek returns nil instead. This seems to me to require a more defensive programming approach. I would like to validate a user input as a valid date in a number of different formats before converting it to a Date and storing it in my model. Iâve tried using the Date parser, e.g. Date readFrom: '04/02/2013' readStream pattern: 'dd/mm/yyyy'. This is fine for simply parsing a valid string but rates a DateError if it doesnât match the .Â So entering â04/13/2013â cleverly raises âDateError: There is no 13th monthâ. My thought was I could use this to return a simple true/false result in a ByteString extension in my application for example as follows: ByteString >> isValdiDate (Date readFrom: self pattern: âdd/mm/yyyyâ) on: DateError do: [^ false]. ^ true However this doesnât intercept the DateError which is simply reported in the Debugger as before.Â Â This may be my lack of uncderstaning of the Exception handling in Pharo. Any and all thoughts welcome. R

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The orange 'content modified' indicator
by Robert Briggs March 3, 2022

March 3, 2022

Hi Pharo browserâs show a little triangular orange triangle in the top right corner when code is edited by the user but not yet Accepted. Is there a mechanism for doing the same, e.g. in an editable SpTextPresenter? Iâve looked around related Spec2 Classes but unable to find a method to do this. Advice please. Regards R

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Dragging objects with restrictions
by Eduardo Ochs March 2, 2022

March 2, 2022

Hi people, I am a beginner with SmallTalks. At the moment I understand the basics about the language but very little about the graphical interface... Can you recommend me docs and tutorials on how to do something like this in Pharo? http://angg.twu.net/eev-videos/2022dragABC.mp4 The link above is to a video that is 20 seconds long. In the first 15 seconds (suggestion: ignore them!) I use weird Emacs tricks to draw three objects in a Tcl/Tk canvas - the letters A, B, and C - and to bind "mousebutton1 motion" to different actions in each of them... ...and in the last 5 seconds of the video I draw the letters A, B and C with the mouse to show what are these actions. In short: the letter A moves freely, the letter B moves in the same horizontal line as A, and when I drag C around it moves B horizontally to force B to be in the same horizontal line as C. Thanks in advance! =) Eduardo Ochs http://angg.twu.net/#eev

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How to unsubscribe?
by contactme＠kathe.in March 2, 2022

March 2, 2022

Hello, I tried issuing the "unsubscribe" and "help" commands to the mailing list management system but didn't get any response. May I know how to go about "unsubscribing" from this mailing list? Thank you. Â

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[PDFtalk] Porting to non-namespace Smalltalks
by christian.haider＠smalltalked-visuals.com March 1, 2022

March 1, 2022

Hi all, PDFtalk is a PDF library for VisualWorks[1]. The library has been ported successfully to Gemstone[2]. Now, there is interest from companies in a port to Squeak and VA Smalltalk. The project[3] has started and we are making good progress. The first step: porting the Values package. This is easy, because there are no namespace issues. The next step is to implement class renamings so that namespaced classes can be renamed to global prefixed names. Then PDFtalk with all its components, except for the UI, can be ported. The porting approach is different to the traditional way of loading and fixing. The import files for other Smalltalks are generated from VisualWorks where the code is transformed by declarative rules. The approach is documented in [4]. I set up a GitHub organization for this project[5]. There, the fileouts for each dialect are published (Gemstone, Squeak and VA Smalltalk so far), so that people without VisualWorks can work with the code in their Smalltalk. Also, I record and explain all steps of the porting process for Squeak in great detail[6], so that people can follow it. I would like to invite Smalltalkers from all dialects to take part in this project. The code transformations for Squeak will be quite similar to the ones needed for Pharo and Cuis. Therefore, each port to one Smalltalk will help the port to other Smalltalks. Any takers? Happy hacking, Christian [1] https://wiki.pdftalk.de/doku.php?id=start [2] https://wiki.pdftalk.de/doku.php?id=pdftalk4gemstone [3] https://wiki.pdftalk.de/doku.php?id=pdftalknonnamespacefileout [4] https://wiki.pdftalk.de/doku.php?id=smalltalktransform [5] https://github.com/PortingPDFtalk [6] https://wiki.pdftalk.de/doku.php?id=valuesportinglog

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Wanted: Backend + Database project
by Santiago Bragagnolo March 1, 2022

March 1, 2022

Hello everybody! In my company we are working on an approach to migrate from monolithic applications to microservices. The approach has been tested on a java project, we are looking now to test it in pharo. For doing so we are looking for a monolithic backend project that proposes some kind of API and uses a database. Does anybody knows about a project that complies to this restrictions? Thanks a lot in advance! Santiago

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Too many parenthesis - a matter of syntax
by Kasper Osterbye March 1, 2022

March 1, 2022

Cheers all I have noticed that I often ends up with quite a number of nested expressions, for example: (((json at: 'tree') select: [ :e | (e at: 'type') = âblob' ]) collect: [:e | Path from: (e at: 'path')]) select: [ :p | p segments last in: [ :name | (name endsWith: '.md') | (name endsWith: '.mic') ] ] What kind of proposals (if any) have been for a different syntax which could give a more streamlined syntax? My own thinking has been around an alternative to the cascade semicolon. What symbol to use does not matter for me, but something like json at: âtree' Âº select: [ :e | ((e at: 'type') = 'blobâ)]Âº collect: [:e | Path from: (e at: 'pathâ)]Âº select: [ :p | p segments last in: [ :name | (name endsWith: '.md') | (name endsWith: '.mic') ] ] Basically, a send the right hand expression to the result of the left hand expression. Has anyone ever tried this, or is it just one of the many small annoyances best left alone? Best, Kasper

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