February 2020 - Pharo-users

[ANN] Pharo-YUML
by Torsten Bergmann Feb. 14, 2020

Feb. 14, 2020

Hi, I published some very simple utility code on https://github.com/astares/Pharo-YUML to easily generate links for YUML. Use the load expression given on the project site or load "YUML" from catalog. Allows you to get a class hierarchy image of an existing Pharo class. It could help to include simple class hierarchy pictures into your (markdown or other) documentation. Example: YUMLGenerator open: String opens a browser to let YUML generate the class hierarchy of String. The clip the URL to your docu as image, for instance in markdown write: ![Hierarchy of String](https://yuml.me/diagram/class/class/[String],[String]%5E-[ByteString],[String]%5E-[Symbol],[Symbol]%5E-[ByteSymbol],[Symbol]%5E-[WideSymbol],[String]%5E-[WideString]) If you need the URL directly then use YUMLGenerator new generateHierarchyFor: String Docu is in https://github.com/astares/Pharo-YUML/blob/master/README.md including an example picture. Maybe it is useful for others too. Thx T.

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enhance object presentation in the inspector for documentation
by Renaud de Villemeur Feb. 13, 2020

Feb. 13, 2020

Hi all. I really like the ability we have in the browser to set and signal method with sample code so we can run them easily by a simple click. The pragma <example> or <script: > are really helpful to document entry point or keep example as small script directly with the code. To have a better grasp of certain object I create, I look at the possibility in the inspector to provide custom object representation. It look like if I add the pragma <gtInspectorPresentationOrder: XX> to some method, it will be added in the inspector as an extra tab with custom representation. Morphic widget are a good example of this. With a quick investigation, I can see that the presentation in those tabs are done by instances of GLMCompositePresentation Given all the discussion I can see on Glamour and GToolkit (for example https://discordapp.com/channels/223421264751099906/445970167495786497/64814…) <https://discordapp.com/channels/223421264751099906/445970167495786497/64814…>, I was wondering if it's was worth the time to understand how to create custom object representation with Glamour or if it will be deprecated in Pharo 9, and what could be the alternatives. Any advise/comment would be welcome. Renaud

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Re: [Pharo-users] Setting a model for a Spec UI in Pharo 8
by Bren Feb. 13, 2020

Feb. 13, 2020

ï»¿Hi fellow Pharo folks, TL;DR: The only apparent way to open a standalone presenter on a user-specified model, SpPresenter>>on:, has a comment suggesting it will be deprecated. As a follow-up to my previous question in case someone DuckDuckGoes it in the future, it seems that adding self modelChanged to SpPresenterWithModel>>setAnnouncingObject: breaks the Spec2 demos. So, I backed my fix out of my image. This has several implications: - To actually change an SpPresenterWithModel's model, one must send model: and then modelChanged. This seems to break encapsulation. - The Spec2 demos seem to rely on modelChanged not arriving before the UI opens. This seems fragile, and reduces the utility of using the demos as examples for writing non-demo code. - Since I can't send modelChanged from model:, I must apparently use SpPresenter>>on: to open a standalone instance of my subclass of SpPresenterWithModel on a model I supply (e.g. (BLFunctionPresenter on: aModel) openWithSpec). I was avoiding this because unfortunately, the comment foreshadows deprecation but does not explain what to use instead. I do not understand how a subclass of SpPresenterWithModel can be composable after this deprecation. So, I have a solution for now, but I am still looking for the supported way to open a standalone presenter on a user-specified model. Bren > On Feb 8, 2020, at 3:22 PM, Bren <asparagi(a)hhhh.org> wrote: > > ï»¿Hi Pharo friends, > > TL;DR: How should one open a presenter on a user-specified model? Is SpPresenterWithModel>>setAnnouncingObject: missing a call to modelChanged? > > The long version: > I am trying to write a UI for my threat modeling tool using Spec in Pharo 8. I had trouble getting my first presenter to show me my model. My current VERY WIP tiny code is available from git@github.com:octotrike/groundhog.git, on branch pharo-sp-presenter-question. > > I wanted to do something like this (paraphrased from the class comment for my BLFunctionPresenter class): > > BLFunctionPresenter new > model: aModel; > openWithSpec > > Unfortunately, the UI continued to show the default announcingObject (nil), even though announcingObject had changed as expected. > > The examples I found showed either > - a containing presenter getting an event, changing instance variables on a presenter it contains, and sending modelChanged, or > - a presenter hard coded to show a model that is globally accessible. > > In the end, I added self modelChanged to the end of SpPresenterWithModel>>setAnnouncingObject:. It seemed like this method changed announcingObject and registered this presenter to receive modelChanged every time changes to the announcingObject occurred. However, in cases like the one I am describing, the change is replacement of the entire announcingObject, so no announcingObject sends modelChanged. > > Was/is this a bug in Spec? Or is there something else I should be doing to open a Spec UI on a model that is neither global nor specified by a parent presenter? > > Bren

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Re: [Pharo-users] [Pharo-dev] [ANN] uFFI Booklet v1.0
by phil＠highoctane.be Feb. 12, 2020

Feb. 12, 2020

Nice. Are callbacks going to be detailed in a future version? They are pretty powerful as one can write a pharo callback to a c method and for debugging, it is golden. Phil á§ On Wed, Feb 12, 2020 at 6:02 PM StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> wrote: > Iâm preparing the website :) > > On 12 Feb 2020, at 10:30, Guillermo Polito <guillermopolito(a)gmail.com> > wrote: > > Hi all, > > We have been working a lot in the last months in the documentation of > uFFI, and we are happy to announce a first stable version of it that youâll > find in a link below :) > The booklet talks about uFFI, how to use it, how marshalling works, how to > use structures, unions, etc. > And it is aimed for the version present on Pharo8.0. > > https://github.com/SquareBracketAssociates/Booklet-uFFI/releases/tag/v1.0.1 > > Of course, a v1 does not mean itâs perfect. Future versions will include > new chapters/features that are on the pipeline such as callbacks and how to > specify string encodings in your bindings. > Also, so if you find something to fix, to add, to remove, or something > hard to follow, let us know > - by email or > - by issue (will be easier to track actually than an email) or > - by PR (and we will have a boost of happiness in addition) > > Cheers, > Guille in behalf of everybody that helped and contributed to this > > > -------------------------------------------- > StÃ©phane Ducasse > http://stephane.ducasse.free.fr / http://www.pharo.org > 03 59 35 87 52 > Assistant: Julie Jonas > FAX 03 59 57 78 50 > TEL 03 59 35 86 16 > S. Ducasse - Inria > 40, avenue Halley, > Parc Scientifique de la Haute Borne, BÃ¢t.A, Park Plaza > Villeneuve d'Ascq 59650 > France > >

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[ANN] uFFI Booklet v1.0
by Guillermo Polito Feb. 12, 2020

Feb. 12, 2020

Hi all, We have been working a lot in the last months in the documentation of uFFI, and we are happy to announce a first stable version of it that youâll find in a link below :) The booklet talks about uFFI, how to use it, how marshalling works, how to use structures, unions, etc. And it is aimed for the version present on Pharo8.0. https://github.com/SquareBracketAssociates/Booklet-uFFI/releases/tag/v1.0.1 <https://github.com/SquareBracketAssociates/Booklet-uFFI/releases/tag/v1.0.1> Of course, a v1 does not mean itâs perfect. Future versions will include new chapters/features that are on the pipeline such as callbacks and how to specify string encodings in your bindings. Also, so if you find something to fix, to add, to remove, or something hard to follow, let us know - by email or - by issue (will be easier to track actually than an email) or - by PR (and we will have a boost of happiness in addition) Cheers, Guille in behalf of everybody that helped and contributed to this

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[ANN] Pharo TechTalk Feb 20: The Colony
by Marcus Denker Feb. 12, 2020

Feb. 12, 2020

A regular chat about Pharo. Happens on Discord. This month a bit a special TechTalk, not about Pharo but about a tool that might be interesting for us to use. Topic: The Colony https://colony.io Introduction to "The Colony", a new platform to Organize and Incentivize Collaborators, Contributors, and Communities. Short demo, followed by some Q&A, help to get people onboarded. https://association.pharo.org/event-3697011 20 Feb 2020 â¢ 1:30 PM - 2:30 PM (EST) NOTE: this is EST time, for Europe, this is 19:30 (the easiest is to download the calendar entry)

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Spec2 and Nuklear?
by Offray Vladimir Luna CÃ¡rdenas Feb. 12, 2020

Feb. 12, 2020

Hi, This is not a question, but more like a blue plan thinking about minimalist native UI toolkits that can talk with Spec 2. I just found Nuklear[1] and I'm kind of wondering if this could take the place of GTK in the Spec2 world. [1] https://github.com/Immediate-Mode-UI/Nuklear Maybe this is just a public note for my future self, put in a bottle, so future others in this community can find it :-). Cheers, Offray

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Dictionary removeKey: very low
by LABORDE Pierre Feb. 11, 2020

Feb. 11, 2020

Hi all, I have a problem with Dictionaries : dic := Dictionary new: 10000. 1 to: 10000 do:[ :i | dic at: i put: i printString. ]. 1 to: 10000 do:[ :i | dic removeKey: i. ] Removing each keys is very slooow, time execution difference between add and remove is crazy. Any idea for fix that ? Can I use another Dictionary implementation or settings ? Thanks. Pierre

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The results are in!
by Richard Kenneth Eng Feb. 11, 2020

Feb. 11, 2020

Round 1 â #1 Leading Team: https://youtu.be/QWHeN5WXfBQ I'm actually quite amazed by their effort. They surpassed my expectations. At the risk of sounding immodest, I think this is a terrific way to promote Smalltalk (Pharo). I think the video is an absolute blast. Richard

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Voluntarily cancelling requests ("applying an expiration date")
by Holger Freyther Feb. 11, 2020

Feb. 11, 2020

tl;dr: I am searching for a pattern (later code) to apply expiration to operations. Introduction: One nice aspect of Mongodb is that it has built-in data distribution[1] and configurable retention[2]. The upstream project has a document called "Server Discovery and Monitoring (SDAM)", defining how a client should behave. Martin Dias is currently implementing SDAM in MongoTalk/Voyage and I took it on a test drive. Behavior: My software stack is using Zinc, Zinc-REST, Voyage and Mongo. When a new REST requests arrives I am using Voyage (e.g. >>#selectOne:) which will use MongoTalk. The MongoTalk code needs to select the right server. It's currently done by waiting for a result. Next I started to simulate database outages. The rest clients retried when not receiving a result within two seconds (no back-off/jitter). What happened was roughly the following: [ 1.) ZnServer accepts a new connection 2.) MongoTalk waits for a server longer than 2s "nothing.. the above waits..." ] repeat. Problem: What happened next surprised me. I expected to have a bad time when the database recovers and all the stale (remember the REST clients already gave up and closed the socket) requests will be answered. Instead my image crashed early in my test as the ExternalSemaphoreTable was full. Let's focus on the timeout behavior and discuss the existence of the ExternalSemaphoreTable and the number of entries separately at a different time. To me the two main problems I see are: 1.) Lack of back-pressure for ZnManagingMultiThreadedServer 2.) Disconnect of time between the Application Layer handling REST is allowed to take and down the stack how long MongoTalk may sleep and wait for a server. The first item is difficult. Even answering HTTP 500 when we are out of space in the ExternalSemaphore is difficult... Let's ignore this for now as well. What I look for: 1.) Voluntarily Timeout Inside my Application code I would like to tag an operation with a timeout. This means everything that is done should complete within X seconds. It can be used on a voluntarily basis. >>#lookupPerson "We expect all database operations to complete within two seconds" person := ComputeContext current withTimeout: 2 seconds during: [ repository selectOne: Person where: [:each name | ...], ]. MongoTalk>>stuff "See if the outer context timeout has expired and signal. E.g. before writing something into the socket to keep consistency." ComputeContext current checkExpired. MongoTalk>>other "Sleep for up to the remaining time out (someSemaphore waitTimeoutContext: ComputeContext current) ifFalse: [ SomethingExpired signal. ] 2.) Cancellation More difficult to write in pseudo code (without TaskIt?). In my above case we are waiting for the database to be ready while the client already closed the file descriptor. Now we are not able to see this until much later. The idea is that in addition to the timeout we can pass a block that is called when an operation should be cancelled and the ComputeContext can be checked if something has been cancelled? The above takes inspiration from Go's context package[3]. In Go the context should be passed as parameter but we could make it a Process variable? Question: How do you handle this in your systems? Is this something we can consider for Pharo9? thanks holger [1] It has the concept of "replicationSet" and works by having a primary, secondary and arbiters running. [2] For every write one can configure if the write should succeed immediately (before it is even on disk) or when it has been written to multiple stores (e.g. majority, US and EMEA) [3] https://golang.org/pkg/context/

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