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Re: [Pharo-users] How to break out of endless loop using code?

by StÃ©phane Ducasse

using different process and having synchronisation point to communicate with it? Stef On Apr 21, 2011, at 10:08 PM, DougEdmunds wrote: > I created a class that generates an endless loop. For this example, the loop > just prints 1-10, back and forth. I'd like to stop the loop by using code, > but when it is running, I can't type anything in a workspace. The only way > I can stop it is by a manual interrupt (on XP, using Alt-<period key>) > > Typical run: > x := MyClass2 new. > x myLoop. > > I want to type "x stopLoop" which would set the running variable to false. > > How do I do this? > > -------- > > 'From Pharo1.3a of ''18 January 2011'' [Latest update: #13144] on 21 April > 2011 at 12:59:14 pm'! > Object subclass: #MyClass2 > instanceVariableNames: 'running' > classVariableNames: '' > poolDictionaries: '' > category: 'Sandbox0419'! > > !MyClass2 methodsFor: 'as yet unclassified' stamp: 'DougEdmunds 4/21/2011 > 12:54'! > initialize > super initialize. > running := true. > Transcript clear. > Transcript show: 'try to stop the loop somehow' . > ! ! > > !MyClass2 methodsFor: 'as yet unclassified' stamp: 'DougEdmunds 4/21/2011 > 12:54'! > myLoop > > "running is an instance variable, initialized to true." > > | x up | > Transcript clear. > x := 1. > up := true. > [Transcript show: x; cr. > x >= 10 ifTrue: [up :=false]. > x <= 1 ifTrue: [up := true]. > up ifTrue: [x := x + 1] ifFalse: [x := x - 1]. > (Delay forSeconds: 1) wait. > running ifFalse: [^ x]. > ] repeat. > ! ! > > !MyClass2 methodsFor: 'as yet unclassified' stamp: 'DougEdmunds 4/21/2011 > 12:55'! > stopLoop > running := false. > ! ! > -------- > > -- > View this message in context: http://forum.world.st/How-to-break-out-of-endless-loop-using-code-tp3466747… > Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com. >

April 21, 2011

How to break out of endless loop using code?

by DougEdmunds

I created a class that generates an endless loop. For this example, the loop just prints 1-10, back and forth. I'd like to stop the loop by using code, but when it is running, I can't type anything in a workspace. The only way I can stop it is by a manual interrupt (on XP, using Alt-<period key>) Typical run: x := MyClass2 new. x myLoop. I want to type "x stopLoop" which would set the running variable to false. How do I do this? -------- 'From Pharo1.3a of ''18 January 2011'' [Latest update: #13144] on 21 April 2011 at 12:59:14 pm'! Object subclass: #MyClass2 instanceVariableNames: 'running' classVariableNames: '' poolDictionaries: '' category: 'Sandbox0419'! !MyClass2 methodsFor: 'as yet unclassified' stamp: 'DougEdmunds 4/21/2011 12:54'! initialize super initialize. running := true. Transcript clear. Transcript show: 'try to stop the loop somehow' . ! ! !MyClass2 methodsFor: 'as yet unclassified' stamp: 'DougEdmunds 4/21/2011 12:54'! myLoop "running is an instance variable, initialized to true." | x up | Transcript clear. x := 1. up := true. [Transcript show: x; cr. x >= 10 ifTrue: [up :=false]. x <= 1 ifTrue: [up := true]. up ifTrue: [x := x + 1] ifFalse: [x := x - 1]. (Delay forSeconds: 1) wait. running ifFalse: [^ x]. ] repeat. ! ! !MyClass2 methodsFor: 'as yet unclassified' stamp: 'DougEdmunds 4/21/2011 12:55'! stopLoop running := false. ! ! -------- -- View this message in context: http://forum.world.st/How-to-break-out-of-endless-loop-using-code-tp3466747… Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

April 21, 2011

[COTDC] 53 - AnimatedGIFReadWriter

by laurent laffont

Today: AnimatedGIFReadWriter Comment Of The Day Contest - One Day One Comment Rules: #1: Each day a not commented class is elected. Each day the best comment will be integrated with name of the author(s). #2: If you cannot comment it, deprecate it. Results: http://code.google.com/p/pharo/wiki/CommentOfTheDayContest Laurent Laffont - @lolgzs <http://twitter.com/#!/lolgzs> Pharo Smalltalk Screencasts: http://www.pharocasts.com/ Blog: http://magaloma.blogspot.com/ Developer group: http://cara74.seasidehosting.st

April 21, 2011

Re: [Pharo-users] [Pharo-project] [COTDC] 52 - PCXReadWriter

by laurent laffont

http://code.google.com/p/pharo/issues/detail?id=4072 Thanks Guillermo. Laurent. On Thu, Apr 21, 2011 at 10:40 AM, StÃ©phane Ducasse < stephane.ducasse(a)inria.fr> wrote: > open a bug entry and put your fix :) > > Stef > > On Apr 21, 2011, at 1:05 AM, Guillermo Polito wrote: > > > I am an Image ReadWriter supposed to be in charge of PCX file encoding > and decoding. > > > > Actually, as my instances does not implement understandsImageFormat, they > use the default ^false implementation and I cannot be used. > > I don't have uses in the image also :). > > > > But in case I am fixed, the code to open a morph with a pcx image is: > > > > PCXReadWriter formFromFileNamed: 'anImage.pcx'. > > > > > > ;) > > Guille > > > > On Wed, Apr 20, 2011 at 3:17 PM, laurent laffont < > laurent.laffont(a)gmail.com> wrote: > > Today: PCXReadWriter > > > > > > Comment Of The Day Contest - One Day One Comment > > Rules: > > #1: Each day a not commented class is elected. Each day the best comment > will be integrated with name of the author(s). > > #2: If you cannot comment it, deprecate it. > > Results: http://code.google.com/p/pharo/wiki/CommentOfTheDayContest > > > > Laurent > > > > >

April 21, 2011

Re: [Pharo-users] ++ -- again

by Igor Stasenko

On 21 April 2011 18:06, Lukas Renggli <renggli(a)gmail.com> wrote: >> So, what is your point? > > To prove your (quoted) sentence wrong: "And it works only for numbers > (no pointers > in smalltalk) and so, completely falls out of object model." > Sure it is. Unless you turn it into message send with trick which you described above. But then it become even worse from performance point of view, because of use of block closure for doing simple increment. so, people will be punished from using i++ instead of i := i + 1 which i finding amusing :) -- Best regards, Igor Stasenko AKA sig.

April 21, 2011

Re: [Pharo-users] ++ -- again

by Lukas Renggli

> So, what is your point? To prove your (quoted) sentence wrong: "And it works only for numbers (no pointers in smalltalk) and so, completely falls out of object model." Lukas -- Lukas Renggli www.lukas-renggli.ch

April 21, 2011

Re: [Pharo-users] ++ -- again

by Igor Stasenko

On 21 April 2011 17:37, Lukas Renggli <renggli(a)gmail.com> wrote: >> A ++ operator is evil, because you cannot override or redefine it >> (like any other message). > > In C++ you can. > yep.. been there >> And it works only for numbers (no pointers >> in smalltalk) >> and so, completely falls out of object model. > > It can be done and has been done in Helvetia without falling out of > the object model. > > I don't remember the details, but I was essentially rewriting > > Â Â i++ > > to something along > > Â Â i increment: [ :v | i := v ] > > where you the semantics of #increment: are implemented in the objects > as you wish. For numbers this would be something like: > > Â Â Number>>#increment: aBlock > Â Â Â Â ^ aBlock value: self + 1 > > For other objects other 'meaningful' implementations can be added, for example: > > Â Â SequenceableCollection>>#increment: aBlock > Â Â Â Â ^ aBlock value: self allButFirst , (Array with: self first) > > Â Â Stream>>#increment: aBlock > Â Â Â Â ^ aStream skip: 1 > > Â Â etc. > So, what is your point? Yes, we can extend a syntax. And with Helvetia this is piece of cake. The question - do we need it so much that want to sacrifice a syntax simplicity, consistency and clarity for that? (outside of serving as an example of extending syntax ;) Well, yeah, we can introduce weird stuff at any moment. Things like macros or quasi-quotes will eventually turn once self-explanatory smalltalk code into DSL, where only author can understand what it does... I am fine with having DSLs around with any possible extensions that people may want them to be. But making it to be default syntax? Hell no! -- Best regards, Igor Stasenko AKA sig.

April 21, 2011

Re: [Pharo-users] ++ -- again

by Lukas Renggli

> A ++ operator is evil, because you cannot override or redefine it > (like any other message). In C++ you can. > And it works only for numbers (no pointers > in smalltalk) > and so, completely falls out of object model. It can be done and has been done in Helvetia without falling out of the object model. I don't remember the details, but I was essentially rewriting i++ to something along i increment: [ :v | i := v ] where you the semantics of #increment: are implemented in the objects as you wish. For numbers this would be something like: Number>>#increment: aBlock ^ aBlock value: self + 1 For other objects other 'meaningful' implementations can be added, for example: SequenceableCollection>>#increment: aBlock ^ aBlock value: self allButFirst , (Array with: self first) Stream>>#increment: aBlock ^ aStream skip: 1 etc. Cheers, Lukas -- Lukas Renggli www.lukas-renggli.ch

April 21, 2011

Re: [Pharo-users] [COTDC] 52 - PCXReadWriter

by StÃ©phane Ducasse

open a bug entry and put your fix :) Stef On Apr 21, 2011, at 1:05 AM, Guillermo Polito wrote: > I am an Image ReadWriter supposed to be in charge of PCX file encoding and decoding. > > Actually, as my instances does not implement understandsImageFormat, they use the default ^false implementation and I cannot be used. > I don't have uses in the image also :). > > But in case I am fixed, the code to open a morph with a pcx image is: > > PCXReadWriter formFromFileNamed: 'anImage.pcx'. > > > ;) > Guille > > On Wed, Apr 20, 2011 at 3:17 PM, laurent laffont <laurent.laffont(a)gmail.com> wrote: > Today: PCXReadWriter > > > Comment Of The Day Contest - One Day One Comment > Rules: > #1: Each day a not commented class is elected. Each day the best comment will be integrated with name of the author(s). > #2: If you cannot comment it, deprecate it. > Results: http://code.google.com/p/pharo/wiki/CommentOfTheDayContest > > Laurent >

April 21, 2011

Re: [Pharo-users] ++ -- again

by Igor Stasenko

On 21 April 2011 07:58, Tobias Pape <Das.Linux(a)gmx.de> wrote: > > Am 2011-04-20 um 22:18 schrieb Ted F.A. van Gaalen: > >> Thanks Tobias and Igor for your thoughts about this increment/decrement theme. >> @Tobias: what kind of side effect(s) are you talking about? I don't >> understand, sorry. > > No problem, I wrote a bit complicated. > What I mean is that > Â Â Â Â i++ > instructs the object âiâ to change its state, ie, increment > itself. > However, the Object in âiâ is meant to be an > integer. So, how to interpret that? say, âiâ is 5. > Essentially, > Â Â Â Â i++ > says > Â Â Â Â âfive, change your state to be sixâ > But that would imply, because all integers are the respecive same > over the image, that all fives are suddenly sixes. > > The point is, > in C, variables denote memory cells, and it is a common > operation to say âmemory cell, increment your content by oneâ, > whereas in Smalltalk, a variable denotes an object and > such an increment is rather senseless on integer objects. > > In other words, each integer in a Smalltalk image is > a kind of Singleton. > ( Â Â Â as > Â Â Â Â 1 = 1 " => true" > Â Â Â Â 1 == 1 " => true" > ) > Hence, > | a b | > a := 1. > b := 1. > a = b " => true (a and b have the same content)". > a == b "=> true (ie, they are the indentical object)". > > "but" > > a ++. "hypothetical" > a = b "=> ??, probably false". > a == b " => ??, can't think of that". > yes, because variables in smalltalk are references to objects. and variables in C are memory pointers. A ++ operator is evil, because you cannot override or redefine it (like any other message). And it works only for numbers (no pointers in smalltalk) and so, completely falls out of object model. > > So Long, > Â Â Â Â -Tobias > -- Best regards, Igor Stasenko AKA sig.

April 21, 2011