June 2017 - Pharo-users - lists.pharo.org

Re: [Pharo-users] About patterns, UML and documentation
by jtuchel＠objektfabrik.de June 8, 2017

June 8, 2017

I think the key to this is intention revealing names and comments. And shipping unit tests that are the best example of "running documentation". Take Sven's NeoCSV package as an example. Great documentation and very good method names. and a complete set of tests. Sounds frightening at first if you come from a static typing background, but in my experience it works quite well. There are UML tools. Some even allow round-trips where the UML diagrams can be generated from code (e.g. IBM/Instantiations have the UML Designer add-on), but to be honest, these only put you in high danger of playing with the tool and layout and stuff rather than concentrate on what is important. UML is fine for communicating the raw structure and basic ideas. Generating UML from code on the fly can help understand code, but I've seen too many projects that made the UML design documents an art of itself, and most of the times the diagrams were out of sync anyways... Just my 2 cents, Joachim -- ----------------------------------------------------------------------- Objektfabrik Joachim Tuchel mailto:jtuchel@objektfabrik.de Fliederweg 1 http://www.objektfabrik.de D-71640 Ludwigsburg http://joachimtuchel.wordpress.com Telefon: +49 7141 56 10 86 0 Fax: +49 7141 56 10 86 1

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Re: [Pharo-users] About patterns, UML and documentation
by Todd Blanchard June 8, 2017

June 8, 2017

Hi Marc. In Smalltalk, we rely on naming conventions a lot. The great thing is that Smalltalk selectors/symbols/method names read like English. aDictionary at: aKey put: anObject. aString indexOf: aCharacter startingAt: start ifAbsent: aBlock Seems pretty clear, no? We also rely on comments. For instance this is the class comment for IceRepository - an abstraction of a git repo. I represent an interface to a git repository. My main responsibilities are: - Load/update both baselines and individual packages from the repository. - Commit changes to the local repository and publish them to a remote repository. - Browse other versions of the loaded packages. - Handle branches For the Collaborators Part: State my main collaborators and one line about how I interact with them. Public API and Key Messages - loadPackage: packageName - createBranch: newBranchName Sample usage: Git new origin: 'git@github.com:npasserini/pharo-git-test.git'. git loadPackage: 'Pharo-Git-Test'. Instance Variables - origin: A string representing the url of a remote git repository (used as origin) - repository: An IceGitTreeGitRemoteRepository, which provides underlying git operations. - location: <FileReference> The directory of the local repository. - commitDictionary: <Dictionary of IceCommitInfo> Cached dictonary from commitId (hex string) to all commits in the current branch (in the local repo). - subdirectory: <String> The subdirectory of the local repository which is handled by the underlying GitFileTree - versionDescriptors: <List of GitFileTreePackageEntry> cached list of all package versions saved in the (currently selected branch) of the (local) repository. - announcer: <Announcer> - branch: <IceBranch> currently selected branch. - loadedCode: <IceLoadedCode> Contains information about the loaded code for each package in this repository. (TODO: maybe handle special cases about loading different versions loaded for different packages, see: https://github.com/npasserini/iceberg/issues/139) I hope this helps. -Todd Blanchard > On Jun 7, 2017, at 10:17 PM, Marc Hanisch via Pharo-users <pharo-users(a)lists.pharo.org> wrote: > > > From: Marc Hanisch <marc.hanisch(a)googlemail.com> > Subject: About patterns, UML and documentation > Date: June 7, 2017 at 10:17:11 PM PDT > To: Any question about pharo is welcome <pharo-users(a)lists.pharo.org> > > > Hello, > > I don't know Smalltalk well enough to give myself an answer about the following topic: > > When using design patterns, one benefit of writing interfaces and passing objects, that implement this interface, to methods is, that the reader instantly knows: okay, here the method A expects something that implements method B. > > Due to the nature of being a dynamically typed language, Smalltalk does not need interfaces. An exception object is thrown when a message is passed to an object that does not implement that method. But this message send could be deep inside the code. > > How do you show to the reader of your code your intention, that you are expecting, let's say for example, an iterator or an object that implements method X, Y and Z? > > Just with your method comments? Do you use UML? If so, how (without interfaces that point to the required methods)? > > Sorry, but I think my understanding of OOP is still to much influenced by C++ and Java based teachings... > > Thanks and best regards, > Marc > >

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About patterns, UML and documentation
by Marc Hanisch June 8, 2017

June 8, 2017

Hello, I don't know Smalltalk well enough to give myself an answer about the following topic: When using design patterns, one benefit of writing interfaces and passing objects, that implement this interface, to methods is, that the reader instantly knows: okay, here the method A expects something that implements method B. Due to the nature of being a dynamically typed language, Smalltalk does not need interfaces. An exception object is thrown when a message is passed to an object that does not implement that method. But this message send could be deep inside the code. How do you show to the reader of your code your intention, that you are expecting, let's say for example, an iterator or an object that implements method X, Y and Z? Just with your method comments? Do you use UML? If so, how (without interfaces that point to the required methods)? Sorry, but I think my understanding of OOP is still to much influenced by C++ and Java based teachings... Thanks and best regards, Marc

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How to migrate an object to a subclass of its class but with new inst vars ?
by Steven Costiou June 7, 2017

June 7, 2017

Hi, i'm trying to migrate an object from a given class A to a subclass of A with new inst vars. Can't get it to work. I have a class and an instance of it, say: Object subclass: #A instanceVariableNames: '' |a| a := A new. A has no instance variables. Now i create a subclass B of A with a new inst var: A subclass: #B instanceVariableNames: 'x' I want to do the following: B adoptInstance: a It does'nt work, for what i understand it is because the format of the classes are different (B has an inst var and A has not). How can i make the a object become an instance of B (subclass of a's class), making a acquiring the new inst var x (and in more complex cases keeping its own previous inst vars) ? Steven.

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MD5 is broken (Cryptography)
by casimiro barreto June 7, 2017

June 7, 2017

MD5 (non primitive and with primitive) is broken because it relies on the conversion of Character to SmallInteger so the method shiftBits: Problem happens at ThirthyTwoBitRegister>>reverseLoadFrom:at: which is called from MD5NonPrimitive>>proccessBuffer: Error is: Instance of Character did not understand #bitShift and happened at: reverseLoadFrom: aByteArray at: index "Load my 32-bit value from the four bytes of the given ByteArray starting at the given index. Consider the first byte to contain the most significant bits of the word (i.e., use big-endian byte ordering)." hi := ((aByteArray at: index + 3) bitShift: 8) + ( aByteArray at: index + 2). low := ((aByteArray at: index + 1) bitShift: 8) + ( aByteArray at: index). -- The information contained in this message is confidential and intended to the recipients specified in the headers. If you received this message by error, notify the sender immediately. The unauthorized use, disclosure, copy or alteration of this message are strictly forbidden and subjected to civil and criminal sanctions.

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RewriteToolbuilder question
by werner kassens June 7, 2017

June 7, 2017

Hi, i followed the video and opened the RewriteToolbuilder on some code in pharo4.0. i then tried to keep things simple and made a transformationrule,which i thought would not change anything, by just copying "â@.Statements." into the lower left & right panels (without the " of course).i then press 'generate rule' and get a 'Syntax Error: end of Statement list encountered' with this specification: ^ ArithmeticError signal: 'Negative numbers canEnd of statement list encountered -> ''t be raised to float powers.' . but this part of the code in the upper left panel is just a copy of some unchanged standard pharo4.0 code. where did i go wrong? werner

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NaCl loading failing in Pharo5.0 stable
by Alejandro Infante June 7, 2017

June 7, 2017

Hi! Loading NaCl from the catalog is failing because the ConfigurationOf attempts in the preLoad to download libsodium.dylib from an url that answers 404 error. The url is from dropbox. Who is responsible of that url? Cheers! Alejandro

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Need help for collecting tests usage data
by Benoit Verhaeghe June 7, 2017

June 7, 2017

Hi everyone. I need your help. Iâm working on how pharo developers use the tests. And you are pharo developers. So I developed a plugin and I would like you to download it. You just have to execute this line in a playground Metacello new smalltalkhubUser: 'Pharo' project: 'MetaRepoForPharo60'; configuration: 'TestsUsageAnalyser'; version: #stable; get; load. You will have to do it only one time in one image. Then, if they are update itâll be done automatically and if you create a new image it will be automatically installed. The plugin will collect data on which tests you run. when. and the modifications you'll have done. Normally, it should be completely transparent for the users and the data are anonymous. If you want more details about the project or how it works, you can answer to this mail, or send me an email at benoit.verhaeghe(a)inria.fr or by using discord. Thanks a lot.

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rewrite question
by werner kassens June 7, 2017

June 7, 2017

Hi, where do i find the 'rewrite tool' described in the paper 'Code Transformation by Direct Transformation of ASTs' by Rizun et al? werner

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Tabular Data Structures for Data Analysis - Text Data Grooming
by Ben Coman June 7, 2017

June 7, 2017

Hi Oleks, This is probably out of scope (check with your mentors), but I was curious how text processing and inter-table lookups might fit into you project? Check out the Excel side-story at [1] (starting just above the picture of the red tree) "Everybody thought of Excel as a financial modeling application [...] for creating calculation models with formulas and stuff. ... [but] most people just used Excel to make lists". This is exactly my personal experience. The greatest practical value I've had from Excel is massaging text lists. Some use cases: A. getting a bunch of messy hand typed data that needs cleaning up to be consistent before deriving statistics from it. There is no sense programming the whole workflow since its a highly iterative process to work through issues as you discover them. Issues are on-shot, but you want to apply it to 1000 rows. B. tracking the status of 1000s of drawings as they progress through a workflow. Tagging who is working on each drawing, status and using AutoFilter to print out "Drawings To Go" lists. C. managing a photo shoot for a school ball, recording orders and generating filenames to copy originals to a USB stick to take to the photo lab, such that duplicate orders each have a single file with the filename printed on the back making it easier to sort into envelopes for each order. (This is from last week so I can provide a sample Excel file for it) For a detailed example, sometimes I might need to compare the basenames of the files in two folders: 1. In both folders A & B, from the command line I'd do `ls -l > ls.txt` 2. I'd load both text files into Excel, one per tab, where each line appeared in a single column. 3. I split on spaces to convert single column into multiple columns [2] 4. I'd split off the filename extension. So I'd need to reverse the string to determine the location of the last period and store that in a temporary column. Then two more columns hold the formulas extracting the first and second parts of the split using LEFT() and RIGHT(). 5. Then in next column I'd have a formula using VLOOKUP() [4] to see if a row's basename appears in any row of the other tab. 6. I'd then do conditional formatting highlighting the row green if the VLOOKUP() was found. "Text Data Grooming" would be a popular horizonal application demonstrating Pharo's liveness (indeed Excel can be considered a "live" environment., saving its "image" to a xls file). I'd very much love to use Pharo for this instead of Excel. cheers -ben [1] https://www.joelonsoftware.com/2012/01/06/how-trello-is-different/ [2] https://support.office.com/en-us/article/Split-text-into-different-columns-… [3] https://superuser.com/questions/121618/any-excel-function-that-will-reverse… [4] https://support.office.com/en-us/article/VLOOKUP-function-0bbc8083-26fe-496…

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