November 2013 - Pharo-dev - lists.pharo.org

Re: [Pharo-dev] Losing instance variable addition

by Frank Shearar

On 1 November 2013 03:36, StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> wrote: > > On Oct 31, 2013, at 11:37 PM, Igor Stasenko <siguctua(a)gmail.com> wrote: > >> >> Btw, if you remember, i already proposed how to solve 'extending object's state with arbitrary state' , mainly by changing the object format to support variable number of key-value properties per object. >> Similar to javascript or self, where you can define a new property on a per-object basis. >> This is fairly easy to implement, at VM level, just reserve extra field in object format, >> define the format of key/value dictionary and add primitives to retrieve and store key-based properties for objects. >> What i like in it, that at language side it is cost nothing: you don't have to extend >> the language to formally define the slots (but you may, of course), >> and there's nothing preventing you from using private keys and not giving them away >> to anyone to keep your data private and not exposing it globally (except from reflection tools i guess). >> And, what is important, you are free to use them or not.. and it costs almost nothing in terms of performance, and nothing in terms of formalism and extra rules in language/package/source management etc etc > > you do not need to be at the object level. For me this would be another level of mess. > > When you think about class extensions we get them because methods are not in the scope of the their class > so it was easy to define a method into a file that represented another changeset. > Now we have problem with iv extensions because they are scoped by the class definition. Does this imply that the correct scope for a class extension would be per package? Say package Base defines a class Foo and package Ext adds a slot to Foo, could you model this through an (Squeak) Environment-like way like this?: In your application's Environment Env, Foo is as it's defined by the Base package. When you load Foo into Env, Env stores a _subclass_ of Foo Foo1, adding the slot to Foo1. But Env actually maps Foo1 to Foo. Within Env, looking up "Foo" means finding Foo1, with the extension. In any other Environment, looking up "Foo" finds Foo, without the extension. (This is how I think extending classes with methods should work too, but I'll be the first to admit that this idea is a "what if we..." idea without any real thought into how feasible it is.) frank > Stef >> >> -- >> Best regards, >> Igor Stasenko. >> > >

Nov. 1, 2013

Re: [Pharo-dev] Questions about Athens

by kilon alios

ShivaVG looks definitely as a way to ease the pain of porting to OpenGL. Some notes on the matter. The Cairo backend for OpenGL is opengl but yet its not opengl. What it does is render cairo as a opengl texture. OpenGL true power is in the shaders so you dont get the kind of hardware acceleration you would expect. Speewise as surprising this may sound opengl is not the ideal option, because opengl is mainly 3d orientated. The ideal solution from what I have seen would be something like CUDA or OpenCL, that give direct access to the GPU cores and allow you to do any kind of computation thus liberation from the restrictions of APIs. For example Blender takes advantage of both Opengl and CUDA , the CUDA renderer is phenomenal better because of its flexibility. The problem however is that all that are very technical and it takes quite some dedication to implement. A reason why I abandoned opengl as an idea is that I came to realise that Cairo was already fast enough for my needs. But I still keep that door open for the distant future, ShivaVG with OpenCL would be awesome for really intensive GUIs and complex Graphics and definitely would love to give it another try eventually. On Fri, Nov 1, 2013 at 2:19 AM, Igor Stasenko <siguctua(a)gmail.com> wrote: > > > > On 1 November 2013 00:53, Alexandre Bergel <alexandre.bergel(a)me.com>wrote: > >> Not sure to fully understand the problem. In what ShivaVG would solve a >> situation better than with Athens? If I understand well, a then working >> with Cairo uses the hardware acceleration right? >> What is it not enough for you need? >> >> First, OpenVG is more complete and i would say thoroughly designed API > than Cairo. > Second, i don't want to go Athens -> Cairo -> OpenGL > if i can do directly Athens->OpenGL. > Putting extra dependency out of the loop is advantageous, OpenGL is widely > supported industry standard, which today you can find even on portable > devices, while you cannot say same about Cairo. > (not mentioning avoiding costs of having multiple layers to get to the > hardware). > > ShivaVG implements OpenVG API using OpenGL, since OpenVG is vector > graphics framework > it can serve as a good source to look how to implement OpenGL backend for > Athens. > > >> Alexandre >> >> > Le 31-10-2013 Ã 19:16, Igor Stasenko <siguctua(a)gmail.com> a Ã©crit : >> > >> > I cannot say, of course, how it would be for you, but there is >> ShivaVG[1] open-source >> > opengl implementation of OpenVG, more or less feature-complete, >> > so all what is needed is to port this code from C to smalltalk. >> > Or if not for porting, but using as a source of insights how to >> implement it. >> > I think it is fairly doable. >> >> > > > -- > Best regards, > Igor Stasenko. >

Nov. 1, 2013

Re: [Pharo-dev] Using Gutenberg

by StÃ©phane Ducasse

the pdf that I sent and that you can find on git hub https://github.com/SquareBracketAssociates/PharoForTheEnterprise-english down down down at the bottom On Oct 31, 2013, at 7:17 PM, Camillo Bruni <camillobruni(a)gmail.com> wrote: > > On 2013-10-31, at 18:27, StÃ©phane Ducasse <stephane.ducasse(a)inria.fr> wrote: > >> read the latex we documented everything. > > which latex file?

Nov. 1, 2013

Re: [Pharo-dev] Losing instance variable addition

by StÃ©phane Ducasse

On Oct 31, 2013, at 11:37 PM, Igor Stasenko <siguctua(a)gmail.com> wrote: > > Btw, if you remember, i already proposed how to solve 'extending object's state with arbitrary state' , mainly by changing the object format to support variable number of key-value properties per object. > Similar to javascript or self, where you can define a new property on a per-object basis. > This is fairly easy to implement, at VM level, just reserve extra field in object format, > define the format of key/value dictionary and add primitives to retrieve and store key-based properties for objects. > What i like in it, that at language side it is cost nothing: you don't have to extend > the language to formally define the slots (but you may, of course), > and there's nothing preventing you from using private keys and not giving them away > to anyone to keep your data private and not exposing it globally (except from reflection tools i guess). > And, what is important, you are free to use them or not.. and it costs almost nothing in terms of performance, and nothing in terms of formalism and extra rules in language/package/source management etc etc you do not need to be at the object level. For me this would be another level of mess. When you think about class extensions we get them because methods are not in the scope of the their class so it was easy to define a method into a file that represented another changeset. Now we have problem with iv extensions because they are scoped by the class definition. Stef > > -- > Best regards, > Igor Stasenko. >

Nov. 1, 2013

Re: [Pharo-dev] Losing instance variable addition

by StÃ©phane Ducasse

The problem is that control version system just save text not text and meta data because a package could have a class definition + in our case a instance variable addition object Now we just save text so this is why we are in trouble. Again this is a text-oriented diff way of the world and this is poor. Stef > > > > On 31 October 2013 08:25, Tudor Girba <tudor(a)tudorgirba.com> wrote: > I completely disagree with this point of view :). > > We should assume an open world, not a close one. From this point of view, any part of the system should be extensible by anyone. In most other languages I know, it is not even possible to extend easily a class with new functionality. In Pharo we can, and we know it is a powerful mechanism. It is not the responsibility of the base class to know what extensions are out there and protect against them. Just like with subclassing, It is in the responsibility of the extender. > > We should be able to do the same with state as well. Without this mechanism, we are forced to put in place clunky dictionary-based mechanism to support state extension. Essentially, any white-box framework does that. For example, Morphic does that, FAMIX and Roassal do that, too (and yes, this is not a bad thing). > > We need this mechanism in the environment, and if I understand Slots correctly, now we have first class support for it. This also means that overrides will be easier to deal with, too. Of course, overrides can induce headaches from time to time, but we should treat these headaches with proper tools, not by forbidding the world to extend. > > And if we are at it, we should also be able to extend a class with Traits, too. > > it is doable, and easily, as others saying nothing prevents you from > saying > SomeClass addInstvarNames: 'foo' > > but the problems in not extending per se, but how you manage it at source level? > > Like you said, we now having slots.. so > then how you think a class definition may look like if some class has extension slots > defined by other package? > > Object subclass: #Point > slots: { > x, y -> Kernel-Classes > z -> ThirdPartyRandomExtensionPackage > z -> SecondThirdPartyRandomExtensionPackage > z -> ThirdThirdPartyRandomExtensionPackage > } > > i am not against being open. > i am against being open to opening can of worms ;) > > (Apart from completely inadequate proportion between effort to implement such feature and supporting it in many tools (MC etc) comparing to the actual/current need of having it). > > Clearly, there is no limits in complexity where we can go in attempt to > describe our systems with metadata up to tiniest level of detail. > Except from some real-world ones: > - implementation effort > - ease of learn & use > - and at last.. sanity :) > > Cheers, > Doru > > > > > On Wed, Oct 30, 2013 at 10:54 PM, Camillo Bruni <camillobruni(a)gmail.com> wrote: > > On 2013-10-30, at 22:36, Igor Stasenko <siguctua(a)gmail.com> wrote: > > > I don't think there's something to fix. > > You cannot 'extend' classes belonging to other package in any other way > > than adding extension methods. > > Allowing extension of ivars or any other vars by foreign package > > is road to nowhere. > > > > I would not like if shape of my kernel classes depends on what packages i load > > or in what order i loaded them. > > To me it is clear that if one needs to add/remove/modify instance variables > > of some class, those changes should belong to the package containing that class, > > not some random package. > > Exactly, it would cause the same problem as we have with overrides in monticello > > > > -- > www.tudorgirba.com > > "Every thing has its own flow" > > > > -- > Best regards, > Igor Stasenko.

Nov. 1, 2013

Re: [Pharo-dev] Questions about Athens

by Igor Stasenko

On 1 November 2013 00:53, Alexandre Bergel <alexandre.bergel(a)me.com> wrote: > Not sure to fully understand the problem. In what ShivaVG would solve a > situation better than with Athens? If I understand well, a then working > with Cairo uses the hardware acceleration right? > What is it not enough for you need? > > First, OpenVG is more complete and i would say thoroughly designed API than Cairo. Second, i don't want to go Athens -> Cairo -> OpenGL if i can do directly Athens->OpenGL. Putting extra dependency out of the loop is advantageous, OpenGL is widely supported industry standard, which today you can find even on portable devices, while you cannot say same about Cairo. (not mentioning avoiding costs of having multiple layers to get to the hardware). ShivaVG implements OpenVG API using OpenGL, since OpenVG is vector graphics framework it can serve as a good source to look how to implement OpenGL backend for Athens. > Alexandre > > > Le 31-10-2013 Ã 19:16, Igor Stasenko <siguctua(a)gmail.com> a Ã©crit : > > > > I cannot say, of course, how it would be for you, but there is > ShivaVG[1] open-source > > opengl implementation of OpenVG, more or less feature-complete, > > so all what is needed is to port this code from C to smalltalk. > > Or if not for porting, but using as a source of insights how to > implement it. > > I think it is fairly doable. > > -- Best regards, Igor Stasenko.

Nov. 1, 2013