June 2011 - Pharo-dev - lists.pharo.org

Re: [Pharo-project] Integer>>#factorial

by Alexandre Bergel

> I agree with Alex, but I don't see why, alex, you say it is a good example for teaching OO (the smalltalk factorial implementation...) This is not something that can be done in Java, the language used for teaching OO in my university. Having methods like #abs, #factorial, #+ defined on Integer is an excellent reason why we do not need a class java.util.Math. These methods look natural to us, but they are not for other people. > For me is a good example of a recursive "function" I agree with you. > I think it would be a good OO example it it was using "object recursion" or the one that could be implemented in a prototyped language... why do you think it is a good oo example the smalltalk factorial implementation? Because it is a natural distribution of responsibility, that cannot be easily done in Java or C#. Alexandre > On Thu, Jun 16, 2011 at 9:52 AM, Alexandre Bergel <alexandre.bergel(a)me.com> wrote: > Hi Sven, > > I am not sure it should replace the standard implementation. Integer>>factorial is essentially there for teaching purpose in my opinion. I am not sure how often factorial is used in practice. The most important for me is not it to be fast, but to be an excellent example of OOP. > > Your implementation could be next to the standard one though. > > Cheers, > Alexandre > > > On 16 Jun 2011, at 06:38, Sven Van Caekenberghe wrote: > > > Hi, > > > > On Planet Smalltalk I read about this challenge: http://www.parcplace.net/list/vwnc-archive/1106/msg00080.html the goal being to optimize the current, naive Integer>>#factorial implementation. > > > > I had some old Lisp code hanging around, implementing an algorithm that I once found somewhere, and I ported it to Smalltalk. I am sure there are faster solutions, but this one is twice as fast as the original while still being easy to understand and it has a useful, safe helper method: > > > > Integer>>#svcFactorial > > "Answer the factorial of the receiver." > > > > self = 0 ifTrue: [ ^ 1 ]. > > self > 0 ifTrue: [ ^ 1 productUpTo: self ]. > > self error: 'Not valid for negative integers' > > > > Integer>>#productUpTo: anInteger > > "Answer the product of all integers from the receiver (non-inclusive) up to anInteger (inclusive)." > > > > | difference split | > > self assert: (self between: 0 and: anInteger). > > "the idea is to multiply LargePositiveIntegers of approximately the same size" > > difference := anInteger - self. > > difference = 0 ifTrue: [ ^ 1 ]. > > difference = 1 ifTrue: [ ^ anInteger ]. > > difference = 2 ifTrue: [ ^ (anInteger - 1) * anInteger ]. > > difference = 3 ifTrue: [ ^ (anInteger - 2) * (anInteger - 1) * anInteger ]. > > difference = 4 ifTrue: [ ^ (anInteger - 3) * (anInteger - 2) * (anInteger - 1) * anInteger ]. > > split := (self + anInteger) bitShift: -1. > > ^ (self productUpTo: split) * (split productUpTo: anInteger) > > > > Would it be a good idea to replace the current implementation with this one ? > > > > Sven > > > > > > -- > _,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;: > Alexandre Bergel http://www.bergel.eu > ^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;. > > > > > > > > > > -- > HernÃ¡n Wilkinson > Agile Software Development, Teaching & Coaching > Mobile: +54 - 911 - 4470 - 7207 > email: hernan.wilkinson(a)10Pines.com > site: http://www.10Pines.com > -- _,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;: Alexandre Bergel http://www.bergel.eu ^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;.

June 16, 2011

Re: [Pharo-project] Integer>>#factorial

by Hernan Wilkinson

I agree with Alex, but I don't see why, alex, you say it is a good example for teaching OO (the smalltalk factorial implementation...) For me is a good example of a recursive "function" I think it would be a good OO example it it was using "object recursion" or the one that could be implemented in a prototyped language... why do you think it is a good oo example the smalltalk factorial implementation? On Thu, Jun 16, 2011 at 9:52 AM, Alexandre Bergel <alexandre.bergel(a)me.com>wrote: > Hi Sven, > > I am not sure it should replace the standard implementation. > Integer>>factorial is essentially there for teaching purpose in my opinion. > I am not sure how often factorial is used in practice. The most important > for me is not it to be fast, but to be an excellent example of OOP. > > Your implementation could be next to the standard one though. > > Cheers, > Alexandre > > > On 16 Jun 2011, at 06:38, Sven Van Caekenberghe wrote: > > > Hi, > > > > On Planet Smalltalk I read about this challenge: > http://www.parcplace.net/list/vwnc-archive/1106/msg00080.html the goal > being to optimize the current, naive Integer>>#factorial implementation. > > > > I had some old Lisp code hanging around, implementing an algorithm that I > once found somewhere, and I ported it to Smalltalk. I am sure there are > faster solutions, but this one is twice as fast as the original while still > being easy to understand and it has a useful, safe helper method: > > > > Integer>>#svcFactorial > > "Answer the factorial of the receiver." > > > > self = 0 ifTrue: [ ^ 1 ]. > > self > 0 ifTrue: [ ^ 1 productUpTo: self ]. > > self error: 'Not valid for negative integers' > > > > Integer>>#productUpTo: anInteger > > "Answer the product of all integers from the receiver > (non-inclusive) up to anInteger (inclusive)." > > > > | difference split | > > self assert: (self between: 0 and: anInteger). > > "the idea is to multiply LargePositiveIntegers of approximately the > same size" > > difference := anInteger - self. > > difference = 0 ifTrue: [ ^ 1 ]. > > difference = 1 ifTrue: [ ^ anInteger ]. > > difference = 2 ifTrue: [ ^ (anInteger - 1) * anInteger ]. > > difference = 3 ifTrue: [ ^ (anInteger - 2) * (anInteger - 1) * > anInteger ]. > > difference = 4 ifTrue: [ ^ (anInteger - 3) * (anInteger - 2) * > (anInteger - 1) * anInteger ]. > > split := (self + anInteger) bitShift: -1. > > ^ (self productUpTo: split) * (split productUpTo: anInteger) > > > > Would it be a good idea to replace the current implementation with this > one ? > > > > Sven > > > > > > -- > _,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;: > Alexandre Bergel http://www.bergel.eu > ^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;. > > > > > > > -- *HernÃ¡n Wilkinson Agile Software Development, Teaching & Coaching Mobile: +54 - 911 - 4470 - 7207 email: hernan.wilkinson(a)10Pines.com site: http://www.10Pines.com <http://www.10pines.com/>*

June 16, 2011

Re: [Pharo-project] Fuel serialization - feature/bug

by Yanni Chiu

On 16/06/11 4:44 AM, Mariano Martinez Peck wrote: > Sorry, one more question. One you did seems to be a persistency strategy > for Pier, but I thought it was the import/export utility: > > http://www.lukas-renggli.ch/blog/export-import > > But it seems I was wrong. There is no way so that I can use that > import/export utility with Fuel also? does that require extra effort or > it can use what you did ? What I did, had more to do with implementing a persistency strategy than with serialization. I took a persistency strategy I'd written, that was using SIXX, and changed it to use Fuel. The changes were very minor - just changed the serialize/deserialize methods. I imagine doing the same for the import/export would be just as straightforward. I'm planning to use Fuel for an import/export facility, but I'm trying to export only a portion of a kernel. Since a Pier kernel's objects are highly interconnected then it's a challenge. On the import side of things, one problem is that the transaction log with be voided (i.e. you would be able to reconstruct the kernel from the log - but maybe that's already a problem when you import a whole kernel).

June 16, 2011

Re: [Pharo-project] Fuel serialization - feature/bug

by Yanni Chiu

On 16/06/11 4:24 AM, Mariano Martinez Peck wrote: > Yanni. The tests are green, but I have an error while trying to persist. > If I go to: > > http://localhost:8888/pier/system/management/persistency > > Choose Fuel, and click on "snapshot" I have a key not found error. Do > you have the same or is it working for you? That worked, the one time I tried it. I'm still integrating the code, so I don't have a clear answer at the moment. My system is set up to read in the saved kernel on image startup, so it may not be obvious how to use PRFuelPersistency, in its present form.

June 16, 2011

Re: [Pharo-project] Integer>>#factorial

by Levente Uzonyi

On Thu, 16 Jun 2011, Sven Van Caekenberghe wrote: > Hi, > > On Planet Smalltalk I read about this challenge: http://www.parcplace.net/list/vwnc-archive/1106/msg00080.html the goal being to optimize the current, naive Integer>>#factorial implementation. > > I had some old Lisp code hanging around, implementing an algorithm that I once found somewhere, and I ported it to Smalltalk. I am sure there are faster solutions, but this one is twice as fast as the original while still being easy to understand and it has a useful, safe helper method: > > Integer>>#svcFactorial > "Answer the factorial of the receiver." > > self = 0 ifTrue: [ ^ 1 ]. > self > 0 ifTrue: [ ^ 1 productUpTo: self ]. > self error: 'Not valid for negative integers' > > Integer>>#productUpTo: anInteger > "Answer the product of all integers from the receiver (non-inclusive) up to anInteger (inclusive)." > > | difference split | > self assert: (self between: 0 and: anInteger). > "the idea is to multiply LargePositiveIntegers of approximately the same size" > difference := anInteger - self. > difference = 0 ifTrue: [ ^ 1 ]. > difference = 1 ifTrue: [ ^ anInteger ]. > difference = 2 ifTrue: [ ^ (anInteger - 1) * anInteger ]. > difference = 3 ifTrue: [ ^ (anInteger - 2) * (anInteger - 1) * anInteger ]. > difference = 4 ifTrue: [ ^ (anInteger - 3) * (anInteger - 2) * (anInteger - 1) * anInteger ]. > split := (self + anInteger) bitShift: -1. > ^ (self productUpTo: split) * (split productUpTo: anInteger) > > Would it be a good idea to replace the current implementation with this one ? IMHO no, but if you want really fast algorithms, then you should visit this page: http://www.luschny.de/math/factorial/FastFactorialFunctions.htm Levente > > Sven > > >

June 16, 2011

[Pharo-project] [update 1.3] #13266

by Marcus Denker

13266 ----- Issue 4399: Senders/implementors cannot browse certain methods like #veryDeepFixupWith: http://code.google.com/p/pharo/issues/detail?id=4399 Issue 4405: PharoKernel generation http://code.google.com/p/pharo/issues/detail?id=4405 ... Smalltalk shrinkToKernel generates a 2.5 MB image (headless) -- Marcus Denker -- http://www.marcusdenker.de INRIA Lille -- Nord Europe. Team RMoD.

June 16, 2011

Re: [Pharo-project] Integer>>#factorial

by Alexandre Bergel

Hi Sven, I am not sure it should replace the standard implementation. Integer>>factorial is essentially there for teaching purpose in my opinion. I am not sure how often factorial is used in practice. The most important for me is not it to be fast, but to be an excellent example of OOP. Your implementation could be next to the standard one though. Cheers, Alexandre On 16 Jun 2011, at 06:38, Sven Van Caekenberghe wrote: > Hi, > > On Planet Smalltalk I read about this challenge: http://www.parcplace.net/list/vwnc-archive/1106/msg00080.html the goal being to optimize the current, naive Integer>>#factorial implementation. > > I had some old Lisp code hanging around, implementing an algorithm that I once found somewhere, and I ported it to Smalltalk. I am sure there are faster solutions, but this one is twice as fast as the original while still being easy to understand and it has a useful, safe helper method: > > Integer>>#svcFactorial > "Answer the factorial of the receiver." > > self = 0 ifTrue: [ ^ 1 ]. > self > 0 ifTrue: [ ^ 1 productUpTo: self ]. > self error: 'Not valid for negative integers' > > Integer>>#productUpTo: anInteger > "Answer the product of all integers from the receiver (non-inclusive) up to anInteger (inclusive)." > > | difference split | > self assert: (self between: 0 and: anInteger). > "the idea is to multiply LargePositiveIntegers of approximately the same size" > difference := anInteger - self. > difference = 0 ifTrue: [ ^ 1 ]. > difference = 1 ifTrue: [ ^ anInteger ]. > difference = 2 ifTrue: [ ^ (anInteger - 1) * anInteger ]. > difference = 3 ifTrue: [ ^ (anInteger - 2) * (anInteger - 1) * anInteger ]. > difference = 4 ifTrue: [ ^ (anInteger - 3) * (anInteger - 2) * (anInteger - 1) * anInteger ]. > split := (self + anInteger) bitShift: -1. > ^ (self productUpTo: split) * (split productUpTo: anInteger) > > Would it be a good idea to replace the current implementation with this one ? > > Sven > > -- _,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;: Alexandre Bergel http://www.bergel.eu ^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;.

June 16, 2011

Re: [Pharo-project] [squeak-dev] Morphic on HTML+CSS

by Igor Stasenko

2011/6/15 Janko MivÅ¡ek <janko.mivsek(a)eranova.si>: > S, Colin Putney piÅ¡e: > >>> In light of recent Microsoft surprising U-turn announcement [1] that in >>> Windows 8 it swithes to HTML5 (HTML5+CSS+JavaScript) instead of .NET+WPF >>> and Silverlight for desktop app development it is IMO a right time to >>> think about: >>> >>> 1. is this a clear signal that HTML5 for ALL apps, both desktop and the >>> Â web is inevitable? >> >> No. Apple isn't going that way, and Microsoft is just dipping its toe >> in the water. >> >>> 2. is this a clear signal that we need to rebuild Morphic on top of >>> Â HTML+CSS, to leverage all Morphic advantages and come back >>> Â to bleeding edge again? >> >> Dan Ingalls has done it already: http://lively-kernel.org/ > > Lively is a project to watch and study, but Lively is JavaScript only, > not using HTML and CSS, as far as I know. > > Separation of design with CSS is namely something which really raised > the creativity fo designers on the web. This can help building better > and nicely looking Smalltalk apps too! > indeed. this separation is good. And it would be even better if you separate HTML from the web :) > Janko > > -- > Janko MivÅ¡ek > Aida/Web > Smalltalk Web Application Server > http://www.aidaweb.si > > -- Best regards, Igor Stasenko AKA sig.

June 16, 2011

Re: [Pharo-project] Morphic on HTML+CSS

by Alexandre Bergel

Looks good Dale! Go go go! Alexandre On 15 Jun 2011, at 16:41, Dale Henrichs wrote: > Geert, > > I am currently working on a browser-based IDE for Pharo and GemStone (should work in any other dialect that supports Seaside ... with a little effort). It is called 'tODE -the Object (centric) Development Environment'. I expect to eventually replace the OmniBrowser-based Gemtools with tODE ... > > You can get a picture of what tODE looks like (in Chrome) attached to the email message[1]. > > I am using Seaside mainly to generate the javascript and provide the necessary callback infrastructure ... > > I am not trying to duplicate the window-based development environment we are all familiar with. In a web-browser, it is not natural to be opening and closing tens of windows, so I have taken a very different tack ... all of the action for tODE takes place in a single web-browser tab ... tODE has it's own navigation scheme (Smalltalk expressions), links and tabs ... > > I'm getting relatively close to the point where I can produce a video showing tODE in action... > > [1] http://forum.world.st/usability-of-Pharo-and-Squeak-tp3562378p3568859.html > > ----- Original Message ----- > | From: "Geert Claes" <geert.wl.claes(a)gmail.com> > | To: pharo-project(a)lists.gforge.inria.fr > | Sent: Wednesday, June 15, 2011 1:20:50 PM > | Subject: Re: [Pharo-project] Morphic on HTML+CSS > | > | > | Janko MivÅ¡ek wrote: > | > > | > 1. is this a clear signal that HTML5 for ALL apps, both desktop and > | > the > | > web is inevitable? > | > 2. is this a clear signal that we need to rebuild Morphic on top of > | > HTML+CSS, to leverage all Morphic advantages and come back to > | > bleeding > | > edge again? > | > > | > | I really like the idea Janko and have been thinking for some time > | that > | moving to a fully browser based IDE would be great for Smalltalk. I > | am just > | not sure there are a lot of people with enough free time to tackle > | this task > | though .... unless someone like Instantiations, Gemstone or Cincom > | throws > | some resources at is and is willing to share with the Smalltalk > | community :) > | > | > | -- > | View this message in context: > | http://forum.world.st/Morphic-on-HTML-CSS-tp3596306p3600455.html > | Sent from the Pharo Smalltalk mailing list archive at Nabble.com. > | > | > -- _,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;: Alexandre Bergel http://www.bergel.eu ^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;._,.;:~^~:;.

June 16, 2011

[Pharo-project] Integer>>#factorial

by Sven Van Caekenberghe

Hi, On Planet Smalltalk I read about this challenge: http://www.parcplace.net/list/vwnc-archive/1106/msg00080.html the goal being to optimize the current, naive Integer>>#factorial implementation. I had some old Lisp code hanging around, implementing an algorithm that I once found somewhere, and I ported it to Smalltalk. I am sure there are faster solutions, but this one is twice as fast as the original while still being easy to understand and it has a useful, safe helper method: Integer>>#svcFactorial "Answer the factorial of the receiver." self = 0 ifTrue: [ ^ 1 ]. self > 0 ifTrue: [ ^ 1 productUpTo: self ]. self error: 'Not valid for negative integers' Integer>>#productUpTo: anInteger "Answer the product of all integers from the receiver (non-inclusive) up to anInteger (inclusive)." | difference split | self assert: (self between: 0 and: anInteger). "the idea is to multiply LargePositiveIntegers of approximately the same size" difference := anInteger - self. difference = 0 ifTrue: [ ^ 1 ]. difference = 1 ifTrue: [ ^ anInteger ]. difference = 2 ifTrue: [ ^ (anInteger - 1) * anInteger ]. difference = 3 ifTrue: [ ^ (anInteger - 2) * (anInteger - 1) * anInteger ]. difference = 4 ifTrue: [ ^ (anInteger - 3) * (anInteger - 2) * (anInteger - 1) * anInteger ]. split := (self + anInteger) bitShift: -1. ^ (self productUpTo: split) * (split productUpTo: anInteger) Would it be a good idea to replace the current implementation with this one ? Sven

June 16, 2011