Beginners July 2008

beginners@lists.squeakfoundation.org

62 participants
72 discussions

Another extension proposal -> subsets
by cdrick 25 Jul '08

25 Jul '08

When we don't find method, we reinvent the wheel. Ok, so this is what happened with my quest on rounding float. So here is another example. I needed a method subsets ... to have all subsets of a Set... #(1 2 ) asSet subsets " -> a Set(a Set(1 2) a Set(1) a Set(2) a Set()) " Is there already something ? I couldn't find so here is what I did ? probably hackish (because of the binary mask) so feel free to comment ;) Set>>subsets | subsetsSize subsets workArray | workArray := self asArray. subsetsSize := 2 raisedTo: self size. subsets := OrderedCollection new. 1 to: subsetsSize do: [:ea | subsets add: ((workArray masquedBy: (ea printStringBase: 2)) asSet)]. "masque par une conversion binaire" ^subsets asSet "could be an array of sets" ArrayedCollection>>masquedBy: aBitString | result entry bitString | entry := self reverse. bitString := aBitString reverse. result := OrderedCollection new. 1 to: (self size) do: [:ea | ((bitString at: ea ifAbsent: []) = $1) ifTrue: [result add: (entry at: ea)]]. ^result reverse Cédrick

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Does Plopp use Morphic?
by Andy Burnett 24 Jul '08

24 Jul '08

I have just started playing with Plopp (very impressive). The reason I downloaded it was to see the sort of interfaces that people could build in Squeak. What I am wondering is whether the UI is built on top of Morphic, or whether it is completely different. Does anyone know? Cheers AB

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[ANN] SqueakLightII Winter News
by Edgar J. De Cleene 23 Jul '08

23 Jul '08

Update your image, see the news. http://wiki.squeak.org/squeak/6056 I could go from SqueakLightII (should be 3.11) to FunSqueak NOW !! And without your feedback, can't improve. So complaint Edgar P.D. Nos encontramos en la hora latina de #IRC :=)

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Rouding Floats up to a number of decimals - Method Finder
by cdrick 23 Jul '08

23 Jul '08

I couldn't find such a function. I tryed in the method finder but find nothing: MethodFinder methodFor: #(#(1.2288 3) 1.228). Do somebody know if such a method exist ? Meanwhile I did that: Float>>trimAfter: aNumberOfDecimal "roundAfter:" | number | number := 10 raisedTo: aNumberOfDecimal. ^(self * 10^aNumber) truncated "rounded" / 10^aNumber asFloat and still MethodFinder methodFor: #(#(1.2288 3) 1.228) returns '(no single method does that function) ' whereas 1.2288 roundedAfter: 3 returns 1.229 Does anybody know what was wrong in my method finder use ? Thanks Cédrick

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Re: [Newbies] Another extension proposal -> subsets
by Marcin Tustin 23 Jul '08

23 Jul '08

Googling "smalltalk powerset" turns this up: http://www.foldr.org/~michaelw/log/2005/09/ On Wed, Jul 23, 2008 at 11:51 AM, cdrick <cdrick65(a)gmail.com> wrote: > When we don't find method, we reinvent the wheel. Ok, so this is what > happened with my quest on rounding float. So here is another example. > I needed a method subsets ... to have all subsets of a Set... > > #(1 2 ) asSet subsets " -> a Set(a Set(1 2) a Set(1) a Set(2) a Set()) " > > Is there already something ? I couldn't find so here is what I did ? > probably hackish (because of the binary mask) so feel free to comment > ;) > > Set>>subsets > | subsetsSize subsets workArray | > workArray := self asArray. > subsetsSize := 2 raisedTo: self size. > subsets := OrderedCollection new. > 1 to: subsetsSize do: [:ea | > subsets add: ((workArray masquedBy: (ea printStringBase: 2)) > asSet)]. "masque par une conversion binaire" > ^subsets asSet "could be an array of sets" > > ArrayedCollection>>masquedBy: aBitString > | result entry bitString | > entry := self reverse. > bitString := aBitString reverse. > result := OrderedCollection new. > 1 to: (self size) do: [:ea | > ((bitString at: ea ifAbsent: []) = $1) ifTrue: [result > add: (entry > at: ea)]]. > ^result reverse > > Cédrick > > _______________________________________________ > Beginners mailing list > Beginners(a)lists.squeakfoundation.org > http://lists.squeakfoundation.org/mailman/listinfo/beginners > >

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Re: Re[2]: [Newbies] Rouding Floats up to a number of decimals - Method Finder
by Marcin Tustin 23 Jul '08

23 Jul '08

Why is it important to you to have a float? Once you've truncated it, you have a rational number, by definition. Are you sure you want to truncate the number, rather than performing the truncation in the presentation layer? On Wed, Jul 23, 2008 at 10:34 AM, cdrick <cdrick65(a)gmail.com> wrote: > > > > Float has a truncate and round off protocal with metods that truncate > > and round to integer. > > > > So it looks you have to do something like > > > > (aFloat * (10^desiredDecimals) + 0.5) truncated / (10^desiredDecimals) > > > > or without the + 0.5 for truncation. > > > > > close to what I proposed earlier ;-) Just need a conversion to Float > as it returns a fraction. > > so no existing method... Isn't it something common ? > _______________________________________________ > Beginners mailing list > Beginners(a)lists.squeakfoundation.org > http://lists.squeakfoundation.org/mailman/listinfo/beginners >

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Fwd: Re: code Critics 'don't check again' optiion? (was [Newbies] isKindOf considered questionable)
by squeak414＠free.fr 23 Jul '08

23 Jul '08

----- Forwarded message from Lukas Renggli <renggli(a)gmail.com> ----- Date: Mon, 21 Jul 2008 12:25:47 +0200 From: Lukas Renggli <renggli(a)gmail.com> Reply-To: Lukas Renggli <renggli(a)gmail.com> Subject: Re: code Critics 'don't check again' option? (was [Newbies] isKindOf considered questionable) To: "A friendly place to get answers to even the most basic questions about Squeak." <beginners(a)lists.squeakfoundation.org>, squeak414(a)free.fr, Marcus Denker <denker(a)iam.unibe.ch> > If there is interest, I could include the basic functionality into RB > itself. I think that would be much cleaner and easier to use. The latest RB (Refactoring-Core-lr.5.mcz) integrates the functionality to ignore certain SmallLint rules in particular methods. Contrary to the original RB implementation it uses pragmas that are persistent with the method. The original RB used a global dictionary that was not tracked by versioning systems. If the rule 'Messages sent but not implemented' should be ignored for a particular method add the following pragma: <lint: 'Messages sent but not implemented'> Normally you also want to add some more information about your rationale: <lint: 'Messages sent but not implemented' rationale: 'We are doing metaprogramming trickery here' author: 'Lukas Renggli'> Contrary to my original implementation in the Essential package don't put a symbol to identify the rule (that doesn't work without changing a whole lot of RB), but just the title that also appears in the result browsers. Furthermore I added several new rules to Lint: This is to detect not categorized methods, violations to the Law of Demeter and unconditional recursion. These rules were also formerly part of the Essential package and can now be used from the standard RB tools. Cheers, Lukas -- Lukas Renggli http://www.lukas-renggli.ch ----- End forwarded message ----- Hi Damien, Will this automatically be picked up in your dev images? I for one think it will be a really useful addition. ...Stan

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How to shorten a method (using inject: into: ?)
by stan shepherd 22 Jul '08

22 Jul '08

Hi, I have the following method, that code critics flags as long: testMaleMeiosis2 | testSet mCount pCount mTotal pTotal | pTotal := 0. mTotal := 0. Forecaster testMale meiose do: [:strand | testSet := strand testRun. mCount := testSet maternalCount. pCount := testSet paternalCount. mTotal := mTotal + mCount. pTotal := pTotal + pCount]. self should: [mTotal = 100 and: [pTotal = 100]] I'm trying to shorten it, including various attempts with inject: into: , but with no success. Any tips please? ...Stan -- View this message in context: http://www.nabble.com/How-to-shorten-a-method-%28using-inject%3A-into%3A--%… Sent from the Squeak - Beginners mailing list archive at Nabble.com.

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Code critics - Overrides super method without calling it
by stan shepherd 21 Jul '08

21 Jul '08

Hi, I get the possible bug 'Overrides super method without calling it' for things like: Strand>>size ^ genes size I can't find an explanation of this, in case there is some nasty that I'm not aware of. It is not listed at: http://st-www.cs.uiuc.edu/users/brant/Refactory/LintChecks.html Is there a more complete list of code critics messages? Are there cases other than 'Overrides a "special" message' to look out for? Thanks, ...Stan -- View this message in context: http://www.nabble.com/Code-critics---Overrides-super-method-without-calling… Sent from the Squeak - Beginners mailing list archive at Nabble.com.

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isKindOf considered questionable
by stan shepherd 21 Jul '08

21 Jul '08

Hi, I'm using isKindOf as part of my unit tests, self should: [(mare maternalStrand at: 100) isKindOf: Gene]; When I run through the code critics, isKindOf is flagged as a 'questionable message'. I can't find any reference to why it should be so; can someone explain please? Thanks, ...Stan -- View this message in context: http://www.nabble.com/isKindOf-considered-questionable-tp18045399p18045399.… Sent from the Squeak - Beginners mailing list archive at Nabble.com.

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Beginners July 2008