November 2017 - Pharo-users

FFIExternalEnumeration int versus long
by Ben Coman Nov. 15, 2017

Nov. 15, 2017

I have a C definition... unsigned long FPDF_GetLastError(); whose return values are... #define FPDF_ERR_SUCCESS 0 // No error. #define FPDF_ERR_UNKNOWN 1 // Unknown error. #define FPDF_ERR_FILE 2 // File not found or could not be opened. #define FPDF_ERR_FORMAT 3 // File not in PDF format or corrupted. #define FPDF_ERR_PASSWORD 4 // Password required or incorrect password. #define FPDF_ERR_SECURITY 5 // Unsupported security scheme. #define FPDF_ERR_PAGE 6 // Page not found or content error. I was thinking of turning those #define's into an FFIExternalEnumeration, but I was wondering if I'll hit some undefined behaviour with the underlying representation being a "long" rather than an "int" ? I do see here that C enumerations can be a range of types including "long" * https://stackoverflow.com/questions/7093360/c-sharp-enum-of-long-values but I'm not sure how it works in the Pharo context to know what the size underlying representation. cheers -ben

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PhD in IoT and Pharo
by Stephane Ducasse Nov. 14, 2017

Nov. 14, 2017

Hi we have a PhD position in France around IoT and Pharo. Description Over the last years, the RMOD team of INRIA Lille and the CAR theme of IMT Lille Douai have been working together on creating tiny language core. For example, Guillermo Polito demonstrated in his PhD a fully reflective kernel that fits into 80 kb of memory and that it is possible to have hyper specialized kernels down to 11 kb. We have also worked on remote debugging (PhD of N. Papoulias) and dynamic code updates (PhD of P. Tesone) of such kernels. All of these works are prototyped in Pharo. More recently, RMOD have been working on advanced probes mechanisms (M. Denker) and a solid remote debugging infrastructure (D. Krudiaskov). The goal of this PhD is to revisit the architecture around such mini-kernels for building IoT applicatons. The following tasks are foreseen : â improve the tools to : edit, compile, debug, deploy and update such kernels on IoT devices. Learning how to debug remotely and dynamically update such IoT systems using the PharmID Pharo environment. This task will be in cooperation with M. Denker and D. Krudiakov on remote debugging for IoT and G. Polito for the kernel edition and tooling, â define some language extensions to manage groups of IoT devices to program them at once. Managing hundreds or even thousands of IoT devices is a challenging task. We want to explore different solutions to help deploying and updating groups of IoT devices using some registration mechanism in a cloud server or some groups/roles based approaches for example, â expressing the architecture of IoT applications. We would like to explore also how to express IoT architectures and what are the abstractions that should be offered to developers such as expressing event-driven architectures with declarative ECA (Event-Conditions-Actions) rules. But we will study a couple of typical IoT appli- cations. â dynamically update an IoT application. An IoT application needs to adapt itself because unreachable or faulty devices or the diminution of available bandwith. We would like that the whole application can reconfigure itself in such situations as Guillaume Grondin proposes it in its PhD. â Lighweight virtual machines. Virtual machines in the IoT context are very powerful for incremental deployment or dynamic updates. Although they are tuned for speed,they consume space compared to a non VM-based program. In this task, we would like to investigate what is the minimal memory consumption that we can reach for a VM usable for IoT. To do so we will use a standard VM such as Cog (the open- source virtual machine of Pharo) and degrade it. We will use it since our minimal kernels are running on it. Note that ZweiDenker GmbH is interested in collaboration on the IoT management cloud infrastructure. Application To apply, please send us : â a CV, â a copy of your Master diploma â a copy of your Master thesis â 2 (two) reference letters, with the contact details of the referents â links to videos of demos of your experiments and/or simulations The application materials should be sent by email to Prof. S. Ducasse stephane.ducasse(a)inria.fr. Email subject must start with : [PhD-RMoD- CAR-2017]. Bibliography â G Polito, St Ìephane Ducasse, N Bouraqadi, L Fabresse, M Mattone. Virtualization Support for Dynamic Core Library Update. Onward !, Oct 2015, Pittsburg, USA. â Guillermo Polito. Virtualization Support for Application Runtime Virtualization and Extension. Ph.D. Thesis 2015. Co-delivr Ìee par lâUniversit Ìe de Lille et lâE Ìcole des Mines de Douai. â Extended results of Tornado : A Run-Fail-Grow approach for Dynamic Application Tayloring. Commanditeur : E Ìcole des mines de Douai, France. 50p, July 2014 â Nick Papoulias, Noury Bouraqadi, Luc Fabresse, St Ìephane Ducasse and Marcus Denker, Mercury : Properties and Design of a Remote Debugging Solution using Reflection, Journal of Object Technology, 14, 1 :1-36, 2015 â Madcar:anabstractmodelfordynamicandautomatic(re-)assemblingofcomponent- based applications G Grondin, N Bouraqadi, L Vercouter. International Symposium on Component-Based Software Engineering, 360-367. Stef and Luc

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extending STON
by henry Nov. 14, 2017

Nov. 14, 2017

Hello, I am trying to extend STON to allow for substitutions as data is written out or read in. On the write side I got it working as #nextPut: is recursively called, so that is the perfect place to substitute before an object is written. I have tested and my changes work well, where I have an arbitrary object as a subObject and it gets substituted out for my Descriptor object. I am having difficult on the read side identifying where a substitution lookup should occur after decoding the object on the input stream. I want to inflate the Descritpor object, with its data, and call for a possible substitution. As it is a Descriptor, it should get substituted with the right bits on the read side. I chose to try and do this in the method #setReference:to: and put the substitute into the objects list. This did not work. Where is a good place to look within STON to do a read-side post-substitution? Thank you. - HH

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QCMagritte on Github
by laurent laffont Nov. 14, 2017

Nov. 14, 2017

Hi, my team starts to use QCMagritte. For our needs we have imported SmalltalkHub repository to Github here: https://github.com/Afibre/QCMagritte I don't know if you (Diego, Stephan, Tobias) plan to use Github instead of SmalltalkHub. At least Github allows branches & pull request. Regards, Laurent Laffont

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when a subclass is loaded, is super-class-side>>initialize executed?
by Ben Coman Nov. 14, 2017

Nov. 14, 2017

Because I'm lazy to experiment this instant (not wanting to get distracted from my current track), and also its probably a useful remainder for others I'll just ask... When MyClass is loaded, #initialize is sent to it. Typically the class-side>>initialize should not call "super initialize" to avoid re-initializing the superclaass, but what if MyClass doesn't implement #initialize? Does the message fall through to the superclass, or is #initialize only sent if MyClass implements it? Concrete example... FFIExternalEnumeration subclass MyEnumeration needs to be sent #initializeEnumeration when it is loaded. We have... FFIExternalEnustmeration>>#initialize self initializeEnumeration so is MyEnumeration *required* to implement its own MyEnumeration>>#initialize, or can it rely FFIExternalEnustmeration>>#initialize. I believe it is the former, but just wanted to confirm my understanding. cheers -ben

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Iterating through two collections in parallel
by Prof. Andrew P. Black Nov. 14, 2017

Nov. 14, 2017

What method will execute a two-parameter block with corresponding pairs of elements from two separate Ordered Collections. something like this example: #(1 2 3) and: 'abc' do: [ :aNumber :aLetter | do something first with 1 and $a, then with 2 and $b, and finally with 3 and $c ] I searched for âcorrespondingâ and âpairsâ and failed to find what Iâm looking for. I tried âzipâ. Itâs hard to search for this with an example. Andrew

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Open Debugger, Save and Quit
by Sean P. DeNigris Nov. 14, 2017

Nov. 14, 2017

In a headless image, I'd like to do the following: if there's any error, arrange to have a debugger open on the next (headful) launch, and then save and quit. I'm drawing a blank - how would I do that? I explored various dead ends, the culmination of which was the image-breaking: actualWorkBlock on: Error do: [ [ Smalltalk snapshot: true andQuit: true ] fork. Halt now ] Thanks! ----- Cheers, Sean -- Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

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FileReference>>#moveTo: across filesystems
by Claudio Corrodi Nov. 14, 2017

Nov. 14, 2017

Hi all, Manuel Leuenberger and I ran into an issue with the FileReference>>#moveTo: method last week. On my system, I have "/" and "/home" in two different partitions/file systems. If I do something like the following, Pharo complains with a PrimitiveFailed signal: '/tmp/aFile.txt' asFileReference moveTo: '/home/claudio/aFile.txt' asFileReference I do not know how this is implemented exactly, but assume that the "rename" syscall is used (on Linux systems, that is), which does not work across file systems. The issue does not arise if I moveTo: inside the same filesystem. Is this expected behaviour? It is not obvious (to me) that FileReference>>#moveTo: requires source and target to be on the same filesystem. It would therefore make more sense to me if there were a fallback that copies and deletes if two filesystems are involved (much like "mv" behaves). What do you think? Cheers, Claudio

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Why is compile: breaking my image?
by Peter UhnÃ¡k Nov. 13, 2017

Nov. 13, 2017

This applies to P61 (for some time) and P7. Object compile: '^'. Syntax Error popup -> close now you have two morphic UI processes running and World starts to get corrupted with artifacts around. (and it also in one case manage to actually corrupt the image to the point that I was no longer able to even launch it). Peter

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Re: [Pharo-users] Pharo-users Digest, Vol 55, Issue 102
by ÐÐ¸ÐºÐµÐ½ÑÐ¸Ð¹ ÐÐ¾ÑÐ°Ð¿Ð¾Ð² Nov. 13, 2017

Nov. 13, 2017

Thanks Stef, also thank all of you for your support. It is very important to me and shows that Pharo is really in progress. I didn't ever complained - i just asked simple questions on topics i don't know. And i get lot's of answers to make some decisions. I understand where to get information and what are the prospects of using Pharo. I came to Pharo looking for appropreate Smalltalk implementation after Cincom denied access to its PUL version of VW. I found Pharo as the most advanced but it also has its disadvantages. My project is a desktop GUI application with some hacks with saving data to\from image on-the-fly and lots of GUI dialogs + complex custom GUI control. It is a kind of personal data\information manager. I'm very lazy and i like to read rich manuals more than to investigate complex code. I think it is much more natural when you don't need to study the whole system before you can do simple things. For example, i don't want to waste lots of time to understand what is the difference between bloc and spec, i want to read few paragraphs of manual and look into some class comments, and than do the task. So i think you made a great progress in this direction with Spec - the manual is very clear and allows developing UI with minimal efforts - just to read some abstracts from manual. But in some areas i need to ask somebody who knows much more than i do. And i don't think there could be "dumb questions", but a _lack_of_information_. Also, when something is evident to one - it could be not so evident to another person. That is why i ask such simple things. Also i became accustomed to the situation when platform implements some basic stuff like i wrote earlier (UI tools, i18n, deployment, etc) and it was not evident to me that such modern system as Pharo cannot do it, so i asked about it. I have seen that Pharo is powerful system but i need to decide what to do: 1) create some personal solution based on different answers above. Lots of code investigations, coding and debugging (fixing existed bugs that are not on pharo roadmap). 2) wait until some release of Pharo fix bugs with non-latin paths, implement minimal level of integrated with UI framework i18n and deployment\packaging of applications. Every software developer tries to find the simplest solution for his task. I apologized if i said something wrong, i really didn't want to hurt somebody's feelings. Vikenti. > > We are focused on deployment but not the same way. > We are the first system that bootstrap a core and can load > dependencies on this core. > We have a dependency analyser that is really advanced since it can > check that you have message that are not in extension > of packages that you use. > In January I hope that we will start packaging Applications (versus > packaging code), so that people can deploy > desktop applications more easily. > > Now if people like vikenti wants our support. They should learn how to > engage a discussion with us and not > just complain :) > > Stef >

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