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

Re: [Pharo-users] [Pharo-project] One Liners to Impress Your Friends

by Sven Van Caekenberghe

On 06 Oct 2011, at 16:58, Levente Uzonyi wrote: > Here's a version optimized for readibility & loc: > > Array streamContents: [ :primeStream | > | sieve | > sieve := Array new: 100 withAll: true. > 2 to: sieve size do: [ :each | > (sieve at: each) ifTrue: [ > primeStream nextPut: each. > each * each to: sieve size by: each do: [ :eachMultiple | > sieve at: eachMultiple put: false ] ] ] ]. That is indeed a cooler version. Thanks for the feedback, Levente ! Sven

Oct. 6, 2011

Loading syntax highlighter in Pharo 1.3

by Charles Monteiro

sorry for the newbie question but I pop myself in here once in a while. Just downloaded Pharo 1.3 but decided to not use the one click since I wanted to use the Cog VM. After loading Seaside from Squeak Source , which gave me a couple pre-req missing warnings which I proceeded thru (not of relevance), I began browsing around and noticed that the syntax highlighter was not loaded or active. What do I have to do to get syntax highlighting back on ? thanks -Charles -- View this message in context: http://forum.world.st/Loading-syntax-highlighter-in-Pharo-1-3-tp3879624p387… Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.

Oct. 6, 2011

Re: [Pharo-users] Create object model from AST using visitor

by Norbert Hartl

Lukas, that was exactly the type of mail I needed. I get somehow stuck in my head but now it is floating again. Am 06.10.2011 um 17:48 schrieb Lukas Renggli: >> If I want to create a model from the structure it turns out to be more difficult than I thought it would be. I'm using a visitor for this. In a typical visitor every element is treated in isolation. I can treat subelement B in the visitor but I cannot assign it to its parent A because there is no link. And I'm not really convinced that introducing return values in the visitor is the right way to go. > > The refactoring engine essentially does that. The visitor is a big > #collect: over the AST and each visit-method returns a new/modified > element. I think this is the most natural thing to do in most cases. > Thinking about it again and with all the approaches at hand I think this a good way to go. >> What I need to do is a visitor that transforms one thing into another thing with having the need that existing parent-child relationships need to be preserved through the transformation. > > Another approach would be to keep a stack of the elements visited. > Like this you can always access the parents of the currently > constructed elements. If I remember correctly, Pier has a few of those > visitors. > > If you just need the direct parent, you can only remember the last > parent in an instance variable, this is for example what OmniBrowser > does when building UIs in OBBuilder. > I think this is a good approach if the interface of the objects is rather generic and homogenous. Otherwise it is difficult for the child to know enough about the parent to deal properly with it. > Alternatively you can also choose a different traversal strategy other > than the canonical one from the root to the leaves. PetitParser has a > couple of these visitors that traverse the graphs in "random" order > keeping collections of processed and unprocessed items. > I never thought about this. So I take some time to get a picture what this could mean. > There are many different ways of how you can visit your nodes. Each > approach has its advantages and disadvantages in a particular > use-case. So I guess you need to figure out yourself what works best > for you. > Agreed. Thanks very much! Norbert

Oct. 6, 2011

Re: [Pharo-users] Create object model from AST using visitor

by Lukas Renggli

> If I want to create a model from the structure it turns out to be more difficult than I thought it would be. I'm using a visitor for this. In a typical visitor every element is treated in isolation. I can treat subelement B in the visitor but I cannot assign it to its parent A because there is no link. Â And I'm not really convinced that introducing return values in the visitor is the right way to go. The refactoring engine essentially does that. The visitor is a big #collect: over the AST and each visit-method returns a new/modified element. I think this is the most natural thing to do in most cases. > What I need to do is a visitor that transforms one thing into another thing with having the need that existing parent-child relationships need to be preserved through the transformation. Another approach would be to keep a stack of the elements visited. Like this you can always access the parents of the currently constructed elements. If I remember correctly, Pier has a few of those visitors. If you just need the direct parent, you can only remember the last parent in an instance variable, this is for example what OmniBrowser does when building UIs in OBBuilder. Alternatively you can also choose a different traversal strategy other than the canonical one from the root to the leaves. PetitParser has a couple of these visitors that traverse the graphs in "random" order keeping collections of processed and unprocessed items. There are many different ways of how you can visit your nodes. Each approach has its advantages and disadvantages in a particular use-case. So I guess you need to figure out yourself what works best for you. Lukas -- Lukas Renggli www.lukas-renggli.ch

Oct. 6, 2011

Create object model from AST using visitor

by Norbert Hartl

Hi, I'm writing a parser at the moment. The first step I did using petit parser to get from the grammar to my own AST like structure. Now I like to create my working model from the AST. And I'm thinking what would be the best way to do. If I want to create a model from the structure it turns out to be more difficult than I thought it would be. I'm using a visitor for this. In a typical visitor every element is treated in isolation. I can treat subelement B in the visitor but I cannot assign it to its parent A because there is no link. And I'm not really convinced that introducing return values in the visitor is the right way to go. What I need to do is a visitor that transforms one thing into another thing with having the need that existing parent-child relationships need to be preserved through the transformation. Anyone has an idea. Any hints are appreciated, Norbert

Oct. 6, 2011

One Liners to Impress Your Friends

by Sven Van Caekenberghe

After reading these two post 10 CoffeeScript One Liners to Impress Your Friends http://ricardo.cc/2011/06/02/10-CoffeeScript-One-Liners-to-Impress-Your-Fri… 10 Scala One Liners to Impress Your Friends http://solog.co/scala/10-scala-one-liners-to-impress-your-friends.html I could not help but think why people get so excited about new languages while Smalltalk can and has been doing this for decades. So here are Smalltalk versions of their code (not that the examples are all that impressive): "--- 1. Multiple Each Item in a List by 2 ---" (1 to: 10) collect: [ :each | each * 2 ] "--- 2. Sum a List of Numbers ---" (1 to: 1000) inject: 0 into: [ :sum :each | sum + each ] (1 to: 1000) fold: [ :x :y | x + y ] (1 to: 1000) reduce: [ :x :y | x + y ] (1 to: 1000) sum "--- 3. Verify if Exists in a String ---" | wordList tweet | wordList := #( 'Smalltalk' 'Object-Oriented' 'REST' 'TDD' 'Play Framework' ). tweet := 'This is an example tweet talking about Smalltalk and TDD'. wordList anySatisfy: [ :each | tweet includesSubString: each ] "--- 4. Read in a File ---" (FileStream fileNamed: 'data.txt') contentsOfEntireFile "--- 5. Happy Birthday ---" 1 to: 4 do: [ :each | Transcript crShow: 'Happy Birthday ', (each = 3 ifTrue: [ 'dear Mr. President' ] ifFalse: [ 'to You' ]) ] "--- 6. Filter list of numbers ---" | passed failed | passed := OrderedCollection new. failed := OrderedCollection new. #(49 58 76 82 88 90) do: [ :each | (each > 60 ifTrue: [ passed ] ifFalse: [ failed ] ) add: each ]. { passed. failed } #(49 58 76 82 88 90) groupedBy: [ :each | each > 60 ] "--- 7. Fetch and Parse an XML or JSON web service ---" XMLDOMParser parse: (ZnNeoClient new get: 'http://search.twitter.com/search.atom?&q=pharoproject') JSJsonParser parse: (ZnNeoClient new get: 'http://search.twitter.com/search.json?&q=pharoproject') "--- 8. Find minimum (or maximum) in a List ---" #(14 35 -7 46 98) fold: [ :x :y | x min: y ] #(14 35 -7 46 98) min #(14 35 -7 46 98) fold: [ :x :y | x max: y ] #(14 35 -7 46 98) max "--- 9. Parallel Processing ---" "No such standard support, but multithreading is of course available" "--- 10. Sieve of Eratosthenes ---" "Unreadable code is not a good idea, this is longer but readable" | primes | primes := Array new: 100 withAll: true. primes at: 1 put: false. 2 to: primes size sqrt ceiling do: [ :each | (primes at: each) ifTrue: [ each * 2 to: primes size by: each do: [ :eachMultiple | primes at: eachMultiple put: false ] ] ]. OrderedCollection streamContents: [ :stream | primes doWithIndex: [ :each :index | each ifTrue: [ stream nextPut: index ] ] ] Maybe we could turn this into a blog post after some discussion ? To really show off Smalltalk, we might need a couple more impressive examples. Sven

Oct. 6, 2011

Re: [Pharo-users] ESUG Video upload continuing...

by Davorin Rusevljan

On Thu, Oct 6, 2011 at 11:29 AM, Marcus Denker <marcus.denker(a)inria.fr> wrote: > Hi, > > We are slowly, but steadily uploading videos to Youtube. > > Â Â Â Â http://www.youtube.com/user/esugboard > > There are now 50 videos already. I just wanted to say a big thank to all who gave presentations, and and who worked on video preparation. It is a great resource for those of us who were not able to attend. Davorin Rusevljan http://www.cloud208.com/

Oct. 6, 2011

ESUG Video upload continuing...

by Marcus Denker

Hi, We are slowly, but steadily uploading videos to Youtube. http://www.youtube.com/user/esugboard There are now 50 videos already. The idea is to upload all videos we have from 2008, 2009, 2010 and 2011. In addition, the "Deep into Smalltalk" tutorials. If you want to be notified about single uploads, there are multiple possibilities: - subscribe to Youtube, turn on email notification. This way you get title, screnshot and the Abstract via mail of every video uploaded. - subscribe to http://twitter.com/#!/esugsmalltalk Youtube sends a tweet automatically for every upload. (Please retweet the ones you like!) Marcus -- Marcus Denker -- http://marcusdenker.de

Oct. 6, 2011

Stdb MySQL Protocol Driver update in squeaksource

by Anindya Haldar

A couple of updates to the Stdb* projects in SqueakSource. Project StdbMysqlProtocol: There is a new version of the protocol driver that can now handle authentication for MySQL users with old style (short hash) passwords. It handles the fallback silently during the handshake. This was an issue reported by Andreas for the previous version of the driver package. Project StdbMysqlImpl : There is a new version of the Stdb API implementation for MySQL. This one has some test infrastructure fixes, and consolidates the use of test credentials so that a single username/password combination is used for all tests. The packages were tested with MySQL 5.0.67 community edition under Mac OS X. Best, Anindya

Oct. 2, 2011