January 2012 - Pharo-dev - lists.pharo.org

Re: [Pharo-project] [squeak-dev] Smalltalk for small projects only?
by mkobetic＠gmail.com Jan. 29, 2012

Jan. 29, 2012

"Janko MivÅ¡ek"<janko.mivsek(a)eranova.si> wrote: > Ralph Johnson in his InfoQ interview made an interesting observation: > > 2:55 minute: "Smalltalk made an fundamental error ... image ... you can > build something with 4-5 people what 50 people can build in Java, but if > you take 200 people in Java ... it is really designed for small systems > ... " > > Are we because of the image really destined for relatively small > projects and small systems (of Java 50 people project size)? The "image" argument is one of the easiest to pick when you want to justify your xenophobic reaction to an unfamiliar environment you're about to enter ("... but they are green and have antennas...", never mind that the antennas may actually be useful for something). But there's nothing fundamental about Smalltalk that requires an image, c.f. there are a few Smalltalks that don't make you use one (e.g. Smalltalk/X). It's just frozen state, many IDEs and editors allow you to freeze their state (e.g. Eclipse workspace), it would be a royal pain having to reopen the files you were working on manually every time, wouldn't it. I think the problem is that most newbies, when being introduced to Smalltalk, are immediately confronted with "the image" as if it was something fundamental, like they couldn't get any further until they grok it. But there's nothing preventing you from never saving the image. Just commit your source code (and it could just as easily be a common file based VC in the back there) and quit the image. Always start from a fresh one and load the code back in. In this mode there's (superficially*) no difference between Smalltalk and any other IDE, you write your code, you run it, debug it, commit it, etc. You can completely forget the image if you want, it's just that most seasoned smalltalkers (the ones doing the introduction) have learned to take advantage of the image and using it in all kinds of creative ways, so they want to pass the knowledge along and manage to freak the newbies out in the process. (*) the real difference between Smalltalk and other IDEs, that may or may not be an issue in any particular case, is that the IDE runs in the same memory space using the same code base as the application, so your development can crash the IDE, while other IDEs prefer to crash on their own :-). But I disagree that the image is some sort of technical obstacle to scalability, I think it's completely orthogonal. The only place where it's hard to ignore the image with the image based Smallltalks is deployment. At this stage the image is the "compiled object code", in the same sense that a shared library is "compiled object code". You can (and some do) deploy as a clean base image, load the application code on start and launch the application. That's no different from a java or python app, their base image is just burned into the VM. But it's so much easier to make that snapshot when all of this is finally loaded in memory and ready to run. It loads faster, there are no scattered files to hunt down in the dark corners of the filesystem, makes perfect sense in many (most?) cases. If people are freaked out that they don't need to mess with CLASS_PATH, or PYTHONPATH or what have you, well, it would be quite easy to "fix that", wouldn't it. You could say that every piece of software "has an image". When it is loaded it initializes its runtime structures, lays them out in memory and starts running. Nothing fundamentally different from the base image case, the "image" is just burned into the executable. If the VM was simply embedded in every saved smalltalk image and the resulting file was turned into an executable, you can't really tell the difference. The image just wouldn't be portable anymore. So I could agree that the image can be an obstacle to adoption if you rub it in people's face, but it can just as easily be mostly ignored. It's not significant unless you make it so in your development process.

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[Pharo-project] browsers vs. guis
by Tudor Girba Jan. 28, 2012

Jan. 28, 2012

Hi, Working with Glamour requires a slightly different mindset than when working with a generic user interface framework. Because this seems to generate confusion, I wrote down a small post that explains the differences. http://www.humane-assessment.com/blog/browsers-vs-guis Still issues? Just shoot, and I will try my best to answer them. Cheers, Doru -- www.tudorgirba.com "Live like you mean it."

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Re: [Pharo-project] [squeak-dev] Smalltalk for small projects only?
by Michael Haupt Jan. 28, 2012

Jan. 28, 2012

Karl, Am 28.01.2012 um 20:39 schrieb karl ramberg <karlramberg(a)gmail.com>: > Is there any work done on managing live images with several developers ? I'm not all sure I understand your question, but: http://www.hpi.uni-potsdam.de/hirschfeld/misc/etc/index.html Best, Michael

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[Pharo-project] FSFileSystem: modification date
by DÃ©bora Fortini Jan. 28, 2012

Jan. 28, 2012

While using FileSystem I found that the memory storage doesn't save the modification date. Here is an example of what is failing: fs := FSFilesystem memory. file := (fs/'hello') withExtension: 'txt'. file fileStreamDo: [ :stream | stream nextPutAll: 'foo' ]. file entry modification ---> 1901-01-01T00:00:00-03:00 This is a little awkward, because I want to use the memory storage to write tests... Should I open a bug entry? isn't it a bug? Thank you in advance! Deby

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[Pharo-project] MongoTalk
by Lucio Santi Jan. 28, 2012

Jan. 28, 2012

Hi! These days I've been playing around with MongoDB and it was a nice surprise to discover the availability of a Smalltalk driver: MongoTalk. When I tried to install it on Pharo v1.3, however, every test failed because of a message sent to a nonexistent class. This class was GRCodec, if I recall well. Does anyone know something about this? Thanks in advance! Lucio

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[Pharo-project] [update 1.4] #14297
by StÃ©phane Ducasse Jan. 28, 2012

Jan. 28, 2012

14297 ----- - Issue 5172: Change SystemAnnouncement names. http://code.google.com/p/pharo/issues/detail?id=5172 - Issue 5221: SystemClassModifiedClassDefinitionAnnouncement is missing. http://code.google.com/p/pharo/issues/detail?id=5221 Stef

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[Pharo-project] Beginner question about "self" in block
by Garret Raziel Jan. 28, 2012

Jan. 28, 2012

Hi, I have one begginer question. It is may be simple, but it very baffles me. I am reading Pharo by Example (great book btw, thanks!). I'm in chapter two where I'm creating Lights Out game. There is this simple code http://pastebin.com/eQregZ35. What baffles me is line 10. I assign "Block of code" to mouseAction variable of LOCell. In this Block, there is "self", that obviously refers to LOGame object in that time. But when is this Block actualy EVALUATED (when I click on Cell), "self" should be reffering to LOCell object, isn't it? If I inspect one LOCell, inspector shows that it has instance variable "mouseAction", which is BlockClosure, that looks like "[self toggleNeighboursOfCellAt: i at: j]". If "LOCell" is the "owner" of this block and also it is the one that evaluates it, shouldn't "self" refer to LOCell object? How BlockClosure desides where "self" actually points? Thanks for explanation. Jan

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[Pharo-project] Customizing Explore
by Ben Coman Jan. 28, 2012

Jan. 28, 2012

I want to customize the Explorer that comes up when you press <shift><alt><i> such that as well as browsing my model, I can have a custom menu on each displayed class to instantiate one of the relationships defined on that class. For example, if the Explorer shows a Library object, then right-clicking on that object will bring up a menu with item "Add book". What are the classes I should be looking at for examples? cheers, Ben

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Re: [Pharo-project] Beginner question about "self" in block
by Marcus Denker Jan. 27, 2012

Jan. 27, 2012

On Jan 27, 2012, at 3:26 PM, Ben Coman wrote: > StÃ©phane Ducasse wrote: >> I guess that in naked objects book they discussed some patterns for relationships. >> What I would love to have is first class slots so that we can easily express relationships like the ones you describe. >> But I have too busy. >> I'm rereading the paper of toon, camillo et all to see what we could reasonably do. >> For those who want to read it: http://rmod.lille.inria.fr/web/pier/publications/bib?&query=Verw11a&display… Toon Verwaest, Camillo Bruni, Mircea Lungu, and Oscar Nierstrasz. Flexible object layouts: enabling lightweight language extensions by intercepting slot access. In Proceedings of OOPSLA '11 Abstract --------- Programming idioms, design patterns and application libraries often introduce cumbersome and repetitive boilerplate code to a software system. Language extensions and external DSLs (domain specific languages) are sometimes introduced to reduce the need for boilerplate code, but they also complicate the system by introducing the need for language dialects and inter-language mediation. To address this, we propose to extend the structural reflective model of the language with object layouts, layout scopes and slots. Based on the new reflective language model we can 1) provide behavioral hooks to object layouts that are triggered when the fields of an object are accessed and 2) simplify the implementation of state-related language extensions such as stateful traits. By doing this we show how many idiomatic use cases that normally require boilerplate code can be more effectively supported. We present an implementation in Smalltalk, and illustrate its usage through a series of extended examples. -- Marcus Denker -- http://marcusdenker.de

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[Pharo-project] cogwin/Croquet (Win7) + Moose + very large models = crash (out of Memory)
by Hani Abdeen Jan. 27, 2012

Jan. 27, 2012

Hello, I'm using cogwin/Croquet VM (last version http://www.mirandabanda.org/files/Cog/VM/VM.r2522/) on windows7, and today I had this probelm: when the size of the pharo image become so large the VM crashes with reason 'out of memory'. The same problem with previous versions of cogwin. Note that I use a PC with 8G of RAM, so it's really damage to have such a problem. Any idea about another VM working well on Windows and does not have such an issues? Any urgent solution? Thanks, Hani

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