Squeak-dev November 1999

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Question: Dual ScrollPane
by Torsten.Bergmann＠phaidros.com 30 Nov '99

30 Nov '99

The normal ScrollPane only scrolls vertical. Is there a morph that can scroll horizontally and vertically ? -Torsten

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RE: Intervals
by Jarvis, Robert P. 30 Nov '99

30 Nov '99

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[ENH???] Re: Weak references Once more
by Henrik Gedenryd 30 Nov '99

30 Nov '99

One more fix, a minimal change. Now I haven't found any problems for hours... Henrik !WeakRefillArray methodsFor: 'adding/copying' stamp: 'hg 11/30/1999 15:53'! copyWith: element "NB. Non-standard behavior optimized for using WeakArrays: Answer a copy of the receiver that is 1 bigger than the receiver and includes the argument, newElement, at the end, IF there isn't already an empty position which can be reused. hg 11/30/1999 11:00" | index size | "cannot use inherited enumeration methods since I have overridden do: to skip nil:s" index _ 1. size _ self basicSize. [index <= size and: [(self at: index) ~~ nil]] whileTrue: [index _ index + 1]. index <= size ifTrue: [self at: index put: element. ^self] ifFalse: [^self privateCopyWith: element]! !

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RE: Intervals
by Jarvis, Robert P. 30 Nov '99

30 Nov '99

> -----Original Message----- > From: David N. Smith (IBM) [SMTP:dnsmith@watson.ibm.com] > Sent: Tuesday, November 30, 1999 2:45 PM > To: squeak(a)cs.uiuc.edu > Subject: RE: Intervals > > I do think that #includes:, if allowed for an interval, should answer > true for all values that 'anInterval asArray' includes (or, the > equivalent, the set values passed to a #do: block) and false for > others. This is not unreasonable and someone else today posted a > solution (the same method that's in Collection). > > However, it cannot be done with a simple computation. Fudge factors > can only make it look right for your test cases. Try this interval > with your code: > > (1.0e-200 to: 5.0e-200 by: 1.0e-200) asArray > => (1.0e-200 2.0e-200 3.0e-200 4.0e-200 5.0e-200 ) > > Aren't floats fun! :-) > OK. Incorporating Michael Donegan's version of Interval>>valuesInclude: (thanks, Michael), and taking into account Peter Crowther's suggestion to scale the fudge factor by the step value (thanks, Peter), we get the following change set: 'From Squeak2.6 of 11 October 1999 [latest update: #1559] on 30 November 1999 at 3:32:28 pm'! !Interval methodsFor: 'accessing' stamp: 'rpj 11/30/1999 11:04'! includes: aNumber "Determine if aNumber is an element of this interval." ^(self rangeIncludes: aNumber) and: [ self valuesInclude: aNumber ]! ! !Interval methodsFor: 'private' stamp: 'rpj 11/30/1999 15:29'! rangeIncludes: aNumber "Private" ^aNumber between: (self first min: self last) and: (self first max: self last)! ! !Interval methodsFor: 'private' stamp: 'rpj 11/30/1999 15:22'! valuesInclude: aNumber "Private - answer whether or not aNumber is one of the enumerated values in this interval." | val | val _ aNumber - self first / self increment. ^(val - val rounded) abs < (step * 1e-10) ! ! Given this, David, is the problem you observed with the (1.0e-200 to: 5.0e-200 by: 1.0e-200) interval now taken care of? I'm not seeing any unusual behavior, i.e. #includes: answers true where I'd expect it and false where I'd expect it (for the values I tested). Bob Jarvis Compuware @ Timken

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RE: [BUG] Freecell
by agree＠carltonfields.com 30 Nov '99

30 Nov '99

Thanks for all these remarks. I believe that I simply misunderstood how the game worked. Once put in perspective, it all makes sense. > -----Original Message----- > From: MIME :dpennell@quallaby.com > Sent: Tuesday, November 30, 1999 2:34 PM > To: squeak(a)cs.uiuc.edu > Subject: RE: [BUG] Freecell > > > #################################################### > The following message part was sent with the unknown > character set: "WINDOWS-1252" > #################################################### > [snip] > >(only the card I clicked appears, and the stack cannot be moved). > > Refer to the previous discussions about the stack move > policy. The single > card display is because it reverts to the behavior of > displaying a partially > hidden card when you hold the left button down. This is > useful for Aces > where you can't see the suit. Windows FreeCell uses the > right button for > this. > It feels normal on an unordered stack but seems strange if > you are expecting > to pick up an ordered stack this is too big to move. > > -david > > > >

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RE: [BUG] Freecell
by Pennell, David 30 Nov '99

30 Nov '99

[snip] >(only the card I clicked appears, and the stack cannot be moved). Refer to the previous discussions about the stack move policy. The single card display is because it reverts to the behavior of displaying a partially hidden card when you hold the left button down. This is useful for Aces where you can't see the suit. Windows FreeCell uses the right button for this. It feels normal on an unordered stack but seems strange if you are expecting to pick up an ordered stack this is too big to move. -david

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(Fwd) Intervals and numerical orders
by Ivan Tomek 30 Nov '99

30 Nov '99

I think that there is some confusion in this discussion what is an Interval. In Smalltalk, an Interval is a collection and messages such as includes: by convention test for membership - is an object an element of the collection? Hence, 1 to: 20 does not include 1.1 because only 1, 2, 3, ... 20 are the elements of this collection. In mathematics, intervals mean something else and the mathematical meaning requires a different class, not a collection. The name Interval for the existing class seems an unfortunate, but already accepted choice. Ivan ------- Forwarded message follows ------- Date forwarded: 30 Nov 1999 19:04:00 -0000 From: Torsten.Bergmann(a)phaidros.com To: squeak(a)cs.uiuc.edu Subject: Intervals and numerical orders Date sent: Tue, 30 Nov 1999 20:03:11 +0100 Forwarded by: squeak(a)cs.uiuc.edu Send reply to: squeak(a)cs.uiuc.edu Some thought's about the Interval discussion: Squeak and Smalltalk in general mixes mathematical intervals and numerical orders in the Interval class: If we use (1 to: 20) we expect to get an interval with a beginning and an end. We can ask this interval if it includes a number. It should return true if this number is inside the interval. Example: (1 to: 20) includes: 0.9 -> false (1 to: 20) includes: 1 -> true (1 to: 20) includes: 1.1 -> true The interval by itself is continuous. [----] Maybe we should also think about open intervals with infinite beginning or end. [--[ (1 to: oo) includes: 100 factorial -> true oo stands for infinite sign. (1 to: 20 by: 3) means we want to have a collection of numbers like the following: (1,4,7,...,19). The method Integer>>to:by: should therefore return an array, an instance of a new class called NumericalOrder or whatever. As mathematician we would'nt expect an interval as return value, would we. As Smalltalker we would expect an Interval, because we know of the Integer>>to:by: implementation. I've asked some non-smalltalkers about that with the result that people wouldn't expect an interval, because an interval has only a beginning and an end and is continuous. (They also expect the result of 3+4*7 as 31 ;) The only reason for returning an interval is that Smalltalk can safe a lot of memory if it stores only the beginning, the end and an increment. So you can easily iterate through a huge collection of numbers. (1 to: 4000 by: 3) do: [...] -Torsten ------- End of forwarded message ------- Dr. Ivan Tomek, Jodrey School of Computer Science Acadia University Nova Scotia, Canada fax: (902) 585-1067 voice: (902) 585-1467

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Intervals and numerical orders
by Torsten.Bergmann＠phaidros.com 30 Nov '99

30 Nov '99

Some thought's about the Interval discussion: Squeak and Smalltalk in general mixes mathematical intervals and numerical orders in the Interval class: If we use (1 to: 20) we expect to get an interval with a beginning and an end. We can ask this interval if it includes a number. It should return true if this number is inside the interval. Example: (1 to: 20) includes: 0.9 -> false (1 to: 20) includes: 1 -> true (1 to: 20) includes: 1.1 -> true The interval by itself is continuous. [----] Maybe we should also think about open intervals with infinite beginning or end. [--[ (1 to: oo) includes: 100 factorial -> true oo stands for infinite sign. (1 to: 20 by: 3) means we want to have a collection of numbers like the following: (1,4,7,...,19). The method Integer>>to:by: should therefore return an array, an instance of a new class called NumericalOrder or whatever. As mathematician we would'nt expect an interval as return value, would we. As Smalltalker we would expect an Interval, because we know of the Integer>>to:by: implementation. I've asked some non-smalltalkers about that with the result that people wouldn't expect an interval, because an interval has only a beginning and an end and is continuous. (They also expect the result of 3+4*7 as 31 ;) The only reason for returning an interval is that Smalltalk can safe a lot of memory if it stores only the beginning, the end and an increment. So you can easily iterate through a huge collection of numbers. (1 to: 4000 by: 3) do: [...] -Torsten

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RE: Intervals
by Peter Crowther 30 Nov '99

30 Nov '99

Much as I hate to reply to my own mail (to parrot-phrase someone else): > This takes no account of the bounds AFAICS*; it needs fuzzy checks for upper and lower bounds, which previous versions have done. Open mouth, insert foot. My apologies for completely ignoring rangeIncludes: (which probably still needs to be fuzzy to check for the end conditions with floats?) - Peter, somewhat embarrassed

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RE: Intervals
by Peter Crowther 30 Nov '99

30 Nov '99

> val _ aNumber - self first / self increment. > ^ ( val - val rounded ) abs < 1e-10 This takes no account of the bounds AFAICS*; it needs fuzzy checks for upper and lower bounds, which previous versions have done. However, it deals neatly with the scaling problem. * Try (1500 to: 1700 by: 0.01) valuesInclude: 0. I get val as (0 - 1500) / 0.01 = -150,000. val - val rounded will be close to 0, and the test will return true. - Peter

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