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

Re: [Pharo-project] About ~= and ~~

by StÃ©phane Ducasse

Mariano please enhance the comments and publish them :) Stef On Oct 12, 2011, at 5:49 PM, Mariano Martinez Peck wrote: > > > On Wed, Oct 12, 2011 at 5:38 PM, Levente Uzonyi <leves(a)elte.hu> wrote: > On Wed, 12 Oct 2011, Clara Allende wrote: > > Hi guys, > > I'm wondering, why? > > ProtoObject>> ~~ anObject > "Answer whether the receiver and the argument are not the same object > (do not have the same object pointer)." > > self == anObject > ifTrue: [^ false] > ifFalse: [^ true] > > > Hi Carla. I can think about two things. The first one, is the one Levente said, performance. > If you analyze the bycode of this method, you will see that it is extremely fast because: > > 1) #== has an special associated bytecode, that is, them VM maps such bytecode to an specific primitive and it is directly executed. It means that the method #== is really never sent. > 2) ifTrue:ifFalse: is also optimized (inlined) by the compiler. Again, it method is never executed and instead the compiler replace a message send bytecode with jump ones. > > Another possible reason (it may not be the case, but in another places it is), is to prevent VM interruption for check other processes. In summary, the VM checks whether it should execute another process of the queue after a method execution. As you know, some parts of the scheduling process is done at the image side. And from there we lack a way to say to the VM, "please execute this method without checking others processes". Hence, in a few yet very specific places of PRocess, Scheduler, Semaphore, etc, #== is used as a mean of executing something WITHOUT being interrupted. I can imagine that it may happen the same with #~~. So if you implement such method with a #not, you will indeed send a message, proving a possibilty to be interrupted. > > Another reasons, similar to the previous one, is that sometimes #== is also used as a way to avoid executing method. So..there are some methods (I don't remember if #allInstancesDo: or #allObjectsDo:) will loop forever because the loop condition would be creating objects (remember that method execution creates objects such as MethodContext). > So...again, I think it may happen the same with #~~. > > That being said, I agree that the method deserve a GOOD comment explaining the reasons of such optimization. > > Cheers > > > Instead of: > ProtoObject>> ~~ anObject > "Answer whether the receiver and the argument are not the same object > (do not have the same object pointer)." > > ^(self == anObject) not > > And why? > Object >> ~= anObject > "Answer whether the receiver and the argument do not represent the > same object." > > ^self = anObject == false > > Instead of > Object>> ~= anObject > "Answer whether the receiver and the argument do not represent the > same object." > > ^(self = anObject) not. > > Is there any particular reason for this that I'm missing? > > Performance. > > > Levente > > Thanks in advance! > -- > > "*Most good programmers do programming not because they expect to get paid > or get adulation by the public, but because it is fun to program.*" > > Linus Torvalds > > > > > > -- > Mariano > http://marianopeck.wordpress.com >

Oct. 12, 2011

Re: [Pharo-project] About ~= and ~~

by Clara Allende

Ok, now I get it :D Thanks a lot Mariano! On 12 October 2011 12:49, Mariano Martinez Peck <marianopeck(a)gmail.com>wrote: > > > On Wed, Oct 12, 2011 at 5:38 PM, Levente Uzonyi <leves(a)elte.hu> wrote: > >> On Wed, 12 Oct 2011, Clara Allende wrote: >> >> Hi guys, >>> >>> I'm wondering, why? >>> >>> ProtoObject>> ~~ anObject >>> "Answer whether the receiver and the argument are not the same object >>> (do not have the same object pointer)." >>> >>> self == anObject >>> ifTrue: [^ false] >>> ifFalse: [^ true] >>> >>> > Hi Carla. I can think about two things. The first one, is the one Levente > said, performance. > If you analyze the bycode of this method, you will see that it is extremely > fast because: > > 1) #== has an special associated bytecode, that is, them VM maps such > bytecode to an specific primitive and it is directly executed. It means that > the method #== is really never sent. > 2) ifTrue:ifFalse: is also optimized (inlined) by the compiler. Again, it > method is never executed and instead the compiler replace a message send > bytecode with jump ones. > > Another possible reason (it may not be the case, but in another places it > is), is to prevent VM interruption for check other processes. In summary, > the VM checks whether it should execute another process of the queue after a > method execution. As you know, some parts of the scheduling process is done > at the image side. And from there we lack a way to say to the VM, "please > execute this method without checking others processes". Hence, in a few yet > very specific places of PRocess, Scheduler, Semaphore, etc, #== is used as a > mean of executing something WITHOUT being interrupted. I can imagine that it > may happen the same with #~~. So if you implement such method with a #not, > you will indeed send a message, proving a possibilty to be interrupted. > > Another reasons, similar to the previous one, is that sometimes #== is also > used as a way to avoid executing method. So..there are some methods (I don't > remember if #allInstancesDo: or #allObjectsDo:) will loop forever because > the loop condition would be creating objects (remember that method execution > creates objects such as MethodContext). > So...again, I think it may happen the same with #~~. > > That being said, I agree that the method deserve a GOOD comment explaining > the reasons of such optimization. > > Cheers > > > >> Instead of: >>> ProtoObject>> ~~ anObject >>> "Answer whether the receiver and the argument are not the same object >>> (do not have the same object pointer)." >>> >>> ^(self == anObject) not >>> >>> And why? >>> Object >> ~= anObject >>> "Answer whether the receiver and the argument do not represent the >>> same object." >>> >>> ^self = anObject == false >>> >>> Instead of >>> Object>> ~= anObject >>> "Answer whether the receiver and the argument do not represent the >>> same object." >>> >>> ^(self = anObject) not. >>> >>> Is there any particular reason for this that I'm missing? >>> >> >> Performance. >> >> >> Levente >> >> Thanks in advance! >>> -- >>> >>> "*Most good programmers do programming not because they expect to get >>> paid >>> or get adulation by the public, but because it is fun to program.*" >>> >>> Linus Torvalds >>> >>> >> > > > -- > Mariano > http://marianopeck.wordpress.com > > -- "*Most good programmers do programming not because they expect to get paid or get adulation by the public, but because it is fun to program.*" Linus Torvalds

Oct. 12, 2011

Re: [Pharo-project] About ~= and ~~

by Mariano Martinez Peck

On Wed, Oct 12, 2011 at 5:38 PM, Levente Uzonyi <leves(a)elte.hu> wrote: > On Wed, 12 Oct 2011, Clara Allende wrote: > > Hi guys, >> >> I'm wondering, why? >> >> ProtoObject>> ~~ anObject >> "Answer whether the receiver and the argument are not the same object >> (do not have the same object pointer)." >> >> self == anObject >> ifTrue: [^ false] >> ifFalse: [^ true] >> >> Hi Carla. I can think about two things. The first one, is the one Levente said, performance. If you analyze the bycode of this method, you will see that it is extremely fast because: 1) #== has an special associated bytecode, that is, them VM maps such bytecode to an specific primitive and it is directly executed. It means that the method #== is really never sent. 2) ifTrue:ifFalse: is also optimized (inlined) by the compiler. Again, it method is never executed and instead the compiler replace a message send bytecode with jump ones. Another possible reason (it may not be the case, but in another places it is), is to prevent VM interruption for check other processes. In summary, the VM checks whether it should execute another process of the queue after a method execution. As you know, some parts of the scheduling process is done at the image side. And from there we lack a way to say to the VM, "please execute this method without checking others processes". Hence, in a few yet very specific places of PRocess, Scheduler, Semaphore, etc, #== is used as a mean of executing something WITHOUT being interrupted. I can imagine that it may happen the same with #~~. So if you implement such method with a #not, you will indeed send a message, proving a possibilty to be interrupted. Another reasons, similar to the previous one, is that sometimes #== is also used as a way to avoid executing method. So..there are some methods (I don't remember if #allInstancesDo: or #allObjectsDo:) will loop forever because the loop condition would be creating objects (remember that method execution creates objects such as MethodContext). So...again, I think it may happen the same with #~~. That being said, I agree that the method deserve a GOOD comment explaining the reasons of such optimization. Cheers > Instead of: >> ProtoObject>> ~~ anObject >> "Answer whether the receiver and the argument are not the same object >> (do not have the same object pointer)." >> >> ^(self == anObject) not >> >> And why? >> Object >> ~= anObject >> "Answer whether the receiver and the argument do not represent the >> same object." >> >> ^self = anObject == false >> >> Instead of >> Object>> ~= anObject >> "Answer whether the receiver and the argument do not represent the >> same object." >> >> ^(self = anObject) not. >> >> Is there any particular reason for this that I'm missing? >> > > Performance. > > > Levente > > Thanks in advance! >> -- >> >> "*Most good programmers do programming not because they expect to get paid >> or get adulation by the public, but because it is fun to program.*" >> >> Linus Torvalds >> >> > -- Mariano http://marianopeck.wordpress.com

Oct. 12, 2011

Re: [Pharo-project] About ~= and ~~

by Levente Uzonyi

On Wed, 12 Oct 2011, Clara Allende wrote: > Hi guys, > > I'm wondering, why? > > ProtoObject>> ~~ anObject > "Answer whether the receiver and the argument are not the same object > (do not have the same object pointer)." > > self == anObject > ifTrue: [^ false] > ifFalse: [^ true] > > Instead of: > ProtoObject>> ~~ anObject > "Answer whether the receiver and the argument are not the same object > (do not have the same object pointer)." > > ^(self == anObject) not > > And why? > Object >> ~= anObject > "Answer whether the receiver and the argument do not represent the > same object." > > ^self = anObject == false > > Instead of > Object>> ~= anObject > "Answer whether the receiver and the argument do not represent the > same object." > > ^(self = anObject) not. > > Is there any particular reason for this that I'm missing? Performance. Levente > Thanks in advance! > -- > > "*Most good programmers do programming not because they expect to get paid > or get adulation by the public, but because it is fun to program.*" > > Linus Torvalds >

Oct. 12, 2011

[Pharo-project] About ~= and ~~

by Clara Allende

Hi guys, I'm wondering, why? ProtoObject>> ~~ anObject "Answer whether the receiver and the argument are not the same object (do not have the same object pointer)." self == anObject ifTrue: [^ false] ifFalse: [^ true] Instead of: ProtoObject>> ~~ anObject "Answer whether the receiver and the argument are not the same object (do not have the same object pointer)." ^(self == anObject) not And why? Object >> ~= anObject "Answer whether the receiver and the argument do not represent the same object." ^self = anObject == false Instead of Object>> ~= anObject "Answer whether the receiver and the argument do not represent the same object." ^(self = anObject) not. Is there any particular reason for this that I'm missing? Thanks in advance! -- "*Most good programmers do programming not because they expect to get paid or get adulation by the public, but because it is fun to program.*" Linus Torvalds

Oct. 12, 2011

Re: [Pharo-project] When will Fuel file format stabilize?

by btc＠openInWorld.com

Oct. 12, 2011

[Pharo-project] [update 1.4] #14192

by StÃ©phane Ducasse

14192 ----- Cleaning obsolete traits for 4904 Stef

Oct. 12, 2011

[Pharo-project] [update 1.4] #14191

by StÃ©phane Ducasse

The kind of update we all love :) Stef http://code.google.com/p/pharo/issues/detail?id=4904 14191 ----- - Speed improvement: 10 to 12 times faster ! the speed is now very near from what is possible with PluggableListMorph. the TimeProfiler is now very efficient. - made MorphTreeModel composable (see MCSliceMaker which is not a MorphTreeModel subclass anymore) - Start to use Annoucements instead of change/update (see MorphTreeSelectionChanged announcement) - no item forgotten when sliding with the mouse for auto multiselection (as in the TestRunner, try to select items with the mouse, some items are not selected if the mouse slides too fast) - no need for TickList* (8 classes) and no need for a CheckList class

Oct. 12, 2011

Re: [Pharo-project] browser and non existent method

by Sven Van Caekenberghe

On 12 Oct 2011, at 04:54, sergio_101 wrote: > the last time i used this combo, i remember that if you called a non > existent method in the browser, a confirmation would pop up, and if > you confirmed that you indeed wanted to use that non existent method, > it would bring up a code browser on that method. then, all you would > have to do is fill in the method guts and hit continue.. Execute 1 foo MNU dialog > Create button HTH, Sven

Oct. 12, 2011

[Pharo-project] browser and non existent method

by sergio_101

hi, all.. i am starting a relatively big project for fun, and am using pharo/seaside after being away for awhile.. the last time i used this combo, i remember that if you called a non existent method in the browser, a confirmation would pop up, and if you confirmed that you indeed wanted to use that non existent method, it would bring up a code browser on that method. then, all you would have to do is fill in the method guts and hit continue.. am i remembering this correctly? i am using the current seaside one click image .. thanks! -- ---- peace, sergio photographer, journalist, visionary http://www.ThoseOptimizeGuys.com http://www.CodingForHire.com http://www.coffee-black.com http://www.painlessfrugality.com http://www.twitter.com/sergio_101 http://www.facebook.com/sergio101

Oct. 12, 2011