February 2020 - Pharo-users

Re: [Pharo-users] Spec2 and Nuklear?

by Esteban Lorenzano

Hi Offray, If plans are rolling out fine, you should be able to add a new backend like that, yes :) Esteban > On 11 Feb 2020, at 19:59, Offray Vladimir Luna CÃ¡rdenas <offray.luna(a)mutabit.com> wrote: > > 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 > > >

Feb. 11, 2020

Re: [Pharo-users] Dictionary removeKey: very low performance

by Richard O'Keefe

My Dictionary and Set implementations (neither of which inherits from the other) grow but do not shrink. It's easy enough to do, I just have not bothered because I have a significant redesign that improves space and time that needs finishing. I've used the marking-deleted-entries technique in the past. I'd prefer not to do it again. On Tue, 11 Feb 2020 at 07:31, Kasper Ãsterbye <kasper.osterbye(a)gmail.com> wrote: > > Hi RIchard, > > On 9 February 2020 at 17.54.30, Richard O'Keefe (raoknz(a)gmail.com) wrote: > > My library uses separate chaining > (https://en.wikipedia.org/wiki/Hash_table#Separate_chaining) > which makes deletion simple and fast and allows 'null' keys. > > Does your implementation use a fixed number of buckets, or do they grow (and shrink)? > > I had been wondering about doing an open addressing with items marked as deleted to see how it would perform. > > Aka "Another technique for removal is simply to mark the slot as deleted. However this eventually requires rebuilding the table simply to remove deleted records.â from https://en.wikipedia.org/wiki/Open_addressing. > > Best, > > Kasper > > >

Feb. 11, 2020

Re: [Pharo-users] Spec2 and Nuklear?

by tbrunz

Whoops, wrong thread, Steve! You want http://forum.world.st/ANN-Pharo-TechTalk-Feb-20-The-Colony-td5111482.html (The Tech Talks are virtual: Marcus streams them on YouTube; you can access them via Discord on the #techtalk channel.) -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Feb. 11, 2020

Re: [Pharo-users] Spec2 and Nuklear?

by Steve Quezadas

This is interesting. I will surely go to this tech talk, as I'm always interested in finding new and efficient methods of organizing groups. Will this be a youtube streaming of the demo? Or is it mostly chat? What is the best way to use javascript libraries within pharo? amber or pharojs? scarlet? Are there any front-ends for this project available? Are there any "colonies" out in the wild? Are there going to be any physical presentations for this? I am in Los Angeles. On Tue, Feb 11, 2020 at 10:59 AM Offray Vladimir Luna CÃ¡rdenas < offray.luna(a)mutabit.com> wrote: > 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 > > > >

Feb. 11, 2020

Re: [Pharo-users] About DuneSt / ChartJs

by Guillaume Larcheveque

Le mar. 11 fÃ©vr. 2020 Ã 17:07, Sven Van Caekenberghe <sven(a)stfx.eu> a Ã©crit : > Hi, > > I am trying to use DuneSt / ChartJs [ https://github.com/DuneSt/ChartJs ] > and it looks good. Thanks for another nice library. > You're welcome and we are pleased that you use it :-) > > My first question is about loading the code. I would like to load the > minimum possible. I guess the stylesheet code is needed, but not the prism > code ? > You are totally right, Prism is required by the demo to display the code. You will not load it by using the 'core' group > > NeoJSON and Seaside are already in my project's dependencies, but Seaside3 > seems to never resolve to the same thing, so I would like to skip that. Is > that possible ? I have this issue often with Seaside. I could fork and edit > the baseline, but I'd rather not. > I have the same opinion, if you have a solution to manage it in a nice way i would be pleased to add it. I only see as a solution to create a group that do not load Seaside3 but maybe Cyril know a better way to do it (he is far better than me about baselines) > > I got a Bar chart on 2D data running right away. > > But how can I use 'horizontalBar' as type ? > > var myBarChart = new Chart(ctx, { > type: 'horizontalBar', > data: data, > options: options > }); > > I see that the types are encoded a classes, but the list seems rather > limited. > We implemented the minimum that is required for us. It is really easy to add new ones as you already discovered. I will add these as soon as possible or if you already did it, create a pull request. There is many improvement that can be done in this project and it would be great to have your contribution about it. We will move to the new version of the ChartJs library when we will have time to improve it. Of course the API of our project will stay the same and changes will not impact your project. > > Thx, > > Sven > > > -- *Guillaume Larcheveque*

Feb. 11, 2020

Spec2 and Nuklear?

by Offray Vladimir Luna CÃ¡rdenas

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

Feb. 11, 2020

About DuneSt / ChartJs

by Sven Van Caekenberghe

Hi, I am trying to use DuneSt / ChartJs [ https://github.com/DuneSt/ChartJs ] and it looks good. Thanks for another nice library. My first question is about loading the code. I would like to load the minimum possible. I guess the stylesheet code is needed, but not the prism code ? NeoJSON and Seaside are already in my project's dependencies, but Seaside3 seems to never resolve to the same thing, so I would like to skip that. Is that possible ? I have this issue often with Seaside. I could fork and edit the baseline, but I'd rather not. I got a Bar chart on 2D data running right away. But how can I use 'horizontalBar' as type ? var myBarChart = new Chart(ctx, { type: 'horizontalBar', data: data, options: options }); I see that the types are encoded a classes, but the list seems rather limited. Thx, Sven

Feb. 11, 2020

Re: [Pharo-users] The results are in!

by horrido

I shall endeavour to make my posts more meaningful, starting with [ANN]. My bad. Guillermo Polito wrote > Hi Ben, > >> El 9 feb 2020, a las 21:01, Ben Coman < > btc@ > > escribiÃ³: >> >> > This list is for people to *ask* questions about Pharo. Not to diffuse >> any kind of propaganda (pharo related or not). >> >> This list is not just for asking questions. There are plenty of [ANN] >> posts advertising new libraries >> and blogs articles. Following completion of the competition, the MIT >> licensed code repository will be announced here. >> Hopefully it may provide an engaging exercise for Pharo teachers to their >> with their students. > > I know, and I donât mind announcements from time to time. > But announcements are generally marked with [ANN], and are kind of self > explanatory. > The mail Richard sent is, and Iâm sorry to be harsh, spam. > >> > I have the feeling this list has been lately flooded with such >> off-topic messages. >> >> Unfortunately the original post was quite bare and failed to show how it >> was Pharo-topical. >> So I can understand how it triggered you. I hope the additional >> background info provided here alleviates some of your concern about it. > > Maybe. Maybe Richard could work his emails a bit more? > > Iâll quote his original email: > >> > El 8 feb 2020, a las 19:12, Richard Kenneth Eng < > horrido.hobbies@ > <mailto: > horrido.hobbies@ > >> escribiÃ³: >> > >> > Round 1 â #1 Leading Team: https://youtu.be/QWHeN5WXfBQ >> <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 > > I particularly, who hasnât followed the competition, am completely lost > with this email. > With the risk of sounding harsh, again, but trying to give some feedback > Richard can work on: > - The subject does not imply it is an announcement, nor what the results > are related to or how they got there > - For those that are not following this competition: what is this round 1? > Are there many of them? What is this about? are there many teams? > - There is no single link to the competition website, what this is about, > whoever contributed to it... > - Clicking on the link gives a video with a title that is as ambiguous as > this email :( > - I check the description of the video: what is there in the video? not > clear. How will it appear in a youtube search in the future? > At least it seems there are links to the website... > Yet, Really? do I have to watch the video before I can know if this is > interesting for me or not? :P > > Happily these points could be addressed in the future. > >> So with this additional perspective, may one post a week be allowed to >> share the progress of the competition? > > Can the posts have better quality? :/ > > Still, Iâd feel more confortable with an alternative, such as using > discord. > What about having a dedicated #jmrpc channel on discord where people could > ask questions too? > > What about twitter? I havent seen this on twitter. Is it there? > > Now, I already spent too much on this :) > Time to get back to something productive. > > Cheers, > Guille -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Feb. 11, 2020

Re: [Pharo-users] Voluntarily cancelling requests ("applying an expiration date")

by Sabine Manaa

Hi Holger, I did not completely understand your mail but when reading the answer of Sven I remembered that some time ago we also had problems with running out of semaphores. After writing with Esteban Lorenzano, we did the following: 1) Smalltalk vm maxExternalSemaphoresSilently: 65535. at startup of the application 2) setting the default pool size of VOMongoRepository from 10 to 2 (we have our own VOMongoRepository subclass) Perhaps this is not your topic perhaps it helps. Sabine Am Mo., 10. Feb. 2020 um 15:14 Uhr schrieb Sven Van Caekenberghe < sven(a)stfx.eu>: > Hi Holger, > > That is a complicated story ;-) > > But, you running out of external semaphores means that you are using too > many sockets, are not closing/releasing them (in time) and/or your GC does > not run enough to keep up (it is easy to deplete the external semaphore > table without the GC kicking in). > > You must have a loop somewhere that goes too fast and maybe does not clean > up properly while doing so. > > YMMV, but I do similar things -- implement/offer REST services that call > other REST/network services, all with timeouts, in several variations, for > years, and I do not have problems like you describe. > > I would suggest enabling logging so that you can see better where the > allocations happen and if your cleanup code does its work. > > Sven > > PS: Zinc logging is easy, just do > > ZnLogEvent logToTranscript > > > On 9 Feb 2020, at 16:31, Holger Freyther <holger(a)freyther.de> wrote: > > > > 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/ > > > > > > > > >

Feb. 11, 2020

Re: [Pharo-users] [Pharo-dev] [Ann] Concurrent Programming in Pharo is available

by Eliot Miranda

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

Feb. 10, 2020