February 2020 - Pharo-users

Re: [Pharo-users] [Pharo-dev] [Ann] Concurrent Programming in Pharo is available
by Eliot Miranda Feb. 10, 2020

Feb. 10, 2020

Hi Stef, here's my review/feedback On Sun, Feb 9, 2020 at 5:05 AM StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> > wrote: > > > > On http://books.pharo.org/booklet-ConcurrentProgramming/ > In fig 1.1 there needs to be a back arrow from Executing to Runnable which is labelled "Preempted by a higher priority process" or similar. In the label for fig 1.2 the word "pending" should be replaced with "runnable". Page 8, section "Process Priorities" "At any time only one process is executed." should read "At any time only one process is executing." The line starting "Next table lists..." in the last paragraph on page 8 should read "The following table lists...". The section might want to state some thing like "there that the current implementation of the Pharo scheduler has process priorities from 1 to 100. Only some of these are named. But the programmer is free to use any priority within that range that they see fit." It would be good to include examples which did things like "forkAt: Processor userPriority + 1", etc. In the label for Fig 2.1 "ressources" should read "resources". But throughout that section I would word it that "processes need to share resources", but "the process is waiting to acquire the resource". So use the plural for the general case and the singular for the specific case. Sentences such as this: "P0 has finished to use the resources." should read "P0 has finished using the resource." In Section 2.1 Conclusion "Semaphores are the lower synchronisation mechanisms." should read "Semaphores are the lowest level synchronisation mechanisms." Chapter 3, "Scheduler's Principles" should state that "The Smalltalk scheduler is a real-time, cooperative, preemptive across priorities, non-preemptive within priorities, scheduler." The title to Chapter 4.5 "ShareQueue: a nice semaphore example" should read "Share*d*Queue: a nice semaphore example" Most of the paragraphs on page 49 in section 4.5 are still in French and need translating. > S. > > -------------------------------------------- > 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 > > -- _,,,^..^,,,_ best, Eliot

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Re: [Pharo-users] P3 and concurrenty
by Sven Van Caekenberghe Feb. 10, 2020

Feb. 10, 2020

Hi Petter, [ CC-ing the Pharo Users list ] P3Client is not built/designed to be used by multiple processes concurrently. Each database connection is represented by an instance of P3Client and holds some state both at the client as well as at the server side. Typically, in a multi user server application, each connection should have its own P3Client / psql connection. For example, in Seaside, a custom WASession subclass gives each session/user its own p3 connection/client. Is that what you are doing ? If not, you could wrap your db accessing code so that mutual exclusion is provided. For example, you can have a look at AbstractCache #beThreadSafe and #critical: That will then serialise requests and possibly block one onto the other. HTH, Sven PS: another thing to take care of if closing your sql connections when the session is no longer needed. PS: Zinc HTTP does also provide a session mechanism (ZnServerSession[Manager]) but these work with cookies and typically won't help with a REST access pattern. > On 9 Feb 2020, at 14:21, Petter Egesund <petter.egesund(a)gmail.com> wrote: > > Hi Sven > > We are using Pharo as our backend in a project and we have run into a problem with P3. > > The problem seems to be connected to compiled sql statements and concurrency. > > We keep getting this error: Bindcomplete message expected > > Problem seems to be easy to reproduce: > > 1) Compile any sql statement > 2) Use this statement in a query twice (!) in a teapot endpoint > > The run some concurrent queries, like "curl http://localhost:8080/endpoint & curl http://localhost:8080/endpoint.." (add several curls after here). > > One could also use ex. siege (https://manpages.ubuntu.com/manpages/trusty/man1/siege.1.html) for easy reproducing. > > If we chain the curls after each other, like "curl http://localhost:8080/endpoint && https://manpages.ubuntu.com/manpages/trusty/man1/siege.1.html && https://manpages.ubuntu.com/manpages/trusty/man1/siege.1.html.." it seems to work fine, so doing the request sequentially seem to work fine. > > My conclusion is that this must be connected to how teapot handles concurrency in companion with the compiled statements? > > Any clues on this one? We are on Pharo 8.0 with latest version of P3, PG 9.x) > > Best regards > > Petter Egesund (I wrote the heysql-package based on P3)

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Re: [Pharo-users] [Pharo-dev] [Ann] Concurrent Programming in Pharo is available
by ducasse Feb. 10, 2020

Feb. 10, 2020

You are welcome. This is really one of the few resources on the topic and at this level in the ecosystem. In the future I plan to learn and explain monitors because they are better than semaphores or mutexes but I have the learn about them before :). > On 10 Feb 2020, at 20:46, Todd Blanchard <tblanchard(a)mac.com> wrote: > > > From: Todd Blanchard <tblanchard(a)mac.com> > Subject: Re: [Pharo-dev] [Ann] Concurrent Programming in Pharo is available > Date: 10 February 2020 at 20:46:46 CET > To: Pharo Development List <pharo-dev(a)lists.pharo.org> > Cc: Any question about pharo is welcome <pharo-users(a)lists.pharo.org> > > > I have wanted a clean explanation of semaphores and process scheduling for a long time. > > Thanks for this. > > >> On Feb 9, 2020, at 3:58 AM, StÃ©phane Ducasse <stephane.ducasse(a)inria.fr <mailto:stephane.ducasse@inria.fr>> wrote: >> >> On http://books.pharo.org/booklet-ConcurrentProgramming/ <http://books.pharo.org/booklet-ConcurrentProgramming/> >> >> >> S. >> >> -------------------------------------------- >> StÃ©phane Ducasse >> http://stephane.ducasse.free.fr <http://stephane.ducasse.free.fr/> / http://www.pharo.org <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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Re: [Pharo-dev] [Ann] Concurrent Programming in Pharo is available
by Todd Blanchard Feb. 10, 2020

Feb. 10, 2020

I have wanted a clean explanation of semaphores and process scheduling for a long time. Thanks for this. > On Feb 9, 2020, at 3:58 AM, StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> wrote: > > On http://books.pharo.org/booklet-ConcurrentProgramming/ <http://books.pharo.org/booklet-ConcurrentProgramming/> > > > S. > > -------------------------------------------- > StÃ©phane Ducasse > http://stephane.ducasse.free.fr <http://stephane.ducasse.free.fr/> / http://www.pharo.org <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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About "it's not pharo but smalltalk"
by Norbert Hartl Feb. 10, 2020

Feb. 10, 2020

I think it is time again to remind people on this list about a subtle but important difference: pharo is not smalltalk You can read this either way and like it or not. But this is a pharo list which wants to focus on the development and usage of pharo. It is not the place for "all things smalltalk". If you have a smalltalk topic please find the appropriate channel to publish or advocate. There are many smalltalkers out there that do not read this list. So in order to reach the people that are interested in smalltalk there are plenty of better channels to put things there. We know that a bit of off-topic discussion is normal but we want to remind everyone to try keeping that really low or find better channels to put that. Norbert

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The expanding Pharo ecosystem
by Sven Van Caekenberghe Feb. 10, 2020

Feb. 10, 2020

Hi, Let's take a moment to contemplate on the breath and the depth of the expanding Pharo ecosystem. So much is happening that it is very hard to keep track, let alone look at everything or try it out. Marcus' excellent curated Pharo Newsletter is one place to see this. Take the February 2020 list of New/Updated Libraries and Frameworks at the end: https://mailchi.mp/pharo/pharo-newsletter-february-2020 This is one of the longest enumerations I have seen so far. The great thing is that it is like that almost every month. Check out the archive: https://us11.campaign-archive.com/home/?u=6f667565c2569234585a7be77&id=0486… Of course, GitHub is also a good way to see this happening. The main entry being: https://github.com/pharo-project/ Which contains several overviews: https://github.com/pharo-project/PharoMap https://github.com/pharo-open-documentation/awesome-pharo Topic tags automatically organise some projects: https://github.com/topics/pharo https://github.com/topics/pharo-smalltalk What all this comes down to is that Pharo has many recently developed, actively maintained options to get your job done: to model your domain, to build your user interface, to talk to other systems, to speak other protocols, to interface with the world, to deploy and to deliver your applications. Similarly, Pavel recently did a very good job at the describing why Pharo itself is so great: https://github.com/pavel-krivanek/pharoMaterials/blob/master/features/Pharo… So thanks to all of you for helping to make Pharo into what it is. Thanks to our users: for your questions, you're feedback, your bug reports. Thanks to those helping out others on the mailing lists. Thanks to everyone who ever blogged or otherwise wrote about their experiences with Pharo. Thanks to the contributors involved in constantly improving Pharo with Pull Requests, to those working hard to maintain the process and the machinery behind the development process. Thanks to all the developers producing and maintaining the many libraries and frameworks that help us in our day to day work. Thanks to those writing documentation. Thank you. Sven PS: This is already a long email, but I know that I forgot many important points, feel free to add them in reply. -- Sven Van Caekenberghe Proudly supporting Pharo http://pharo.org http://association.pharo.org http://consortium.pharo.org

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[Browser] object is deprecated
by Steve Quezadas Feb. 9, 2020

Feb. 9, 2020

Hello, I am porting a package into Pharo 8. One of the objects is referring to object [Browser], but that does not seem to present in Pharo8 and deprecated in Pharo5. What is the modern replacement for [Browser]? Also, is there a "smaltalk" way to find out recommended replacements for deprecated objects? - Steve PS How do you open object [Browser] in Pharo5, so I can at least visually see it? "Browser new open" and "Browser new openInWorld" both don't work.

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Re: [Pharo-users] The results are in!
by Pavel Krivanek Feb. 9, 2020

Feb. 9, 2020

so 8. 2. 2020 v 23:58 odesÃlatel Benoit St-Jean via Pharo-users < pharo-users(a)lists.pharo.org> napsal: > I guess I have to re-ask again since nobody answered my question from > this week... > > Where can we post Pharo > questions/remarks/thoughts/you-might-want-to-have-a-look-at-this-cool-idea/whatever > > (or anything that could be of any interest to Pharoers) ? > > MAYBE we need another list... > > This is getting ridiculous! The guy spends energy, time, effort and is > able to gather 13K in prizes and puts Pharo to the forefront with this > cool contest in schools, makes a lot of youngsters learn & use Pharo for > their projects, puts up a website, makes videos, writes blog posts, > PROMOTES Pharo and he gets slapped for posting here ?!?! WTF ??? > You need to see the whole story. This guy with a messianic syndrome started his aggressive campaign by spitting on every other programming language and he is constantly spamming the social media by void articles that are often full of lies while showing whole community in a very bad light of fanatic fools. He (alone) came with the idea of the competition and started to demand money for it. Then he started to blame anyone who didn't want to provide money to him. He is constantly rejecting any critique and feedback so do not be surprised that otherwise very friendly people are losing their patience. -- Pavel > > Where should he post? Where should I post ? > > On 2020-02-08 17:35, Guillermo Polito wrote: > > Hi Richard, > > > > Iâd like to invite you to refrain yourself from posting such off-topic > > messages in the future. > > > -- > ----------------- > BenoÃ®t St-Jean > Yahoo! Messenger: bstjean > Twitter: @BenLeChialeux > Pinterest: benoitstjean > Instagram: Chef_Benito > IRC: lamneth > GitHub: bstjean > Blogue: endormitoire.wordpress.com > "A standpoint is an intellectual horizon of radius zero". (A. Einstein) > > >

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NeoJSONParseError: invalid input: ' while parsing a Wikipedia exported article.
by Offray Vladimir Luna CÃ¡rdenas Feb. 9, 2020

Feb. 9, 2020

Hi, I'm trying to read the contents of a Wikipedia article that was exported from there using Wikipedias JSON API. The script I'm trying is: NeoJSONReader fromString:Â 'https://mutabit.com/repos.fossil/pharopedia/doc/tip/docs/wikipedia.org/wiki…' asUrl retrieveContents utf8Decoded But I get "NeoJSONParseError: invalid input: '". As far as I can tell, the file at [1] seems like valid JSON, as is the one that Wikipedia API exports [1] 'https://mutabit.com/repos.fossil/pharopedia/doc/tip/docs/wikipedia.org/wiki…' Could anybody point me to a solution? Thanks, Offray

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Re: [Pharo-users] The results are in!
by Pierce Ng Feb. 9, 2020

Feb. 9, 2020

On Sat, Feb 08, 2020 at 05:50:18PM -0500, Benoit St-Jean via Pharo-users wrote: > MAYBE we need another list... Maybe Richard just needs to adjust the style of his mails... > This is getting ridiculous!Â The guy spends energy, time, effort and is able > to gather 13K in prizes and puts Pharo to the forefront with this cool > contest in schools, makes a lot of youngsters learn & use Pharo for their > projects, puts up a website, makes videos, writes blog posts, PROMOTES Pharo > and he gets slapped for posting here ?!?!Â WTF ??? Like if the subject of Richard's mail is "Pharo success story part 3: blah blah" and his opening paragraph is descriptive, similar to what you wrote above, I'd read the mail and watch the video. As it is, his mail is content-free and comes across purely as self-promotion. Pierce

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