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• CodePlex Daily Summary for Tuesday, June 05, 2012

  CodePlex Daily Summary for Tuesday, June 05, 2012Popular ReleasesApplication Architecture Guidelines: Application Architecture Guidelines 3.0.7: 3.0.7Jolt Environment: Jolt v2 Stable: Many new features. Follow development here for more information: http://www.rune-server.org/runescape-development/rs-503-client-server/projects/298763-jolt-environment-v2.html Setup instructions in downloadtedplay: tedplay 1.0: First public release of the Commodore 264 family (C16, plus/4) music player based on the SDL version of YAPE http://yape.homeserver.hu.SharePoint Euro 2012 - UEFA European Football Predictor: havivi.euro2012.wsp (1.5): New fetures:Multilingual Support Max users property in Standings Web Part Games time zone change (UTC +1) bug fix - Version 1.4 locking problem http://euro2012.codeplex.com/discussions/358262 bug fix - Field Title not found (v.1.3) German SP http://euro2012.codeplex.com/discussions/358189#post844228 Bug fix - Access is denied.for users with contribute rights Bug fix - Installing on non-English version of SharePoint Bug fix - Title Rules Installing SharePoint Euro 2012 PredictorSharePoint E...xNet: xNet 2.1.1: Release xNet 2.1.1Command Line Parser Library: 1.9.2.4 stable: This is the first stable of 1.9.* branch. Added tests for HelpText::AutoBuild. Fixed minor formatting error in HelpText::DefaultParsingErrorsHandler.myManga: myManga v1.0.0.4: ChangeLogUpdating from Previous Version: Extract contents of Release - myManga v1.0.0.4.zip to previous version's folder. Replaces: myManga.exe BakaBox.dll CoreMangaClasses.dll Manga.dll Plugins/MangaReader.manga.dll Plugins/MangaFox.manga.dll Plugins/MangaHere.manga.dll Plugins/MangaPanda.manga.dllMVVM Light Toolkit: V4RC (binaries only) including Windows 8 RP: This package contains all the latest DLLs for MVVM Light V4 RC. It includes the DLLs for Windows 8 Release Preview. An updated Nuget package is also available at http://nuget.org/packages/MvvmLightLibsPreviewExtAspNet: ExtAspNet v3.1.7: +2012-06-03 v3.1.7 -?????????BUG，??????RadioButtonList?，AJAX????????BUG（swtseaman、????）。 +?Grid?BoundField、HyperLinkField、LinkButtonField、WindowField??HtmlEncode?HtmlEncodeFormatString（TiDi）。 -HtmlEncode?HtmlEncodeFormatString??????true，??????HTML????????。 -??????Asp.Net??GridView?BoundField?????????。 -http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.boundfield.htmlencode -?Grid?HyperLinkField、WindowField??UrlEncode??，????URL??（???true）。 -?????????????，?????????????...Ela, functional language: Ela Platform 2012.3: 2012.3 is a stabilization release. It contains several improvements to Ela, std lib and Elide. Ela changes Fix:Op code 'Show' didn't work correctly when a format string was a thunk. Fix:Flipping a function wrapped in a thunk caused VM to crush. Fix:A bug fixed in concatenation of a thunk and a lazy list. Fix:Concatenation of a lazy list and a strict list could cause stack overflow in a case of recursive thunks. Fix:A bug fixed in applying 'show' to a result of a lazy and strict list...Cross Site Treeview - For MOSS 2007: Cross Site Treeview-Beta - WSP Solution: Cross Site Treeview-Beta - WSP SolutionLiveChat Starter Kit: LCSK v1.5.2: New features: Visitor location (City - Country) from geo-location Pass configuration via javascript for the chat box New visitor identification (no more using the IP address as visitor identification) To update from 1.5.1 Run the /src/1.5.2-sql-updates.txt SQL script to update your database tables. If you have it installed via NuGet, simply update your package and the file will be included so you can run the update script. New installation The easiest way to add LCSK to your app is by...Kendo UI ASP.NET Sample Applications: Sample Applications (2012-06-01): Sample application(s) demonstrating the use of Kendo UI in ASP.NET applications.Better Explorer: Better Explorer Beta 1: Finally, the first Beta is here! There were a lot of changes, including: Translations into 10 different languages (the translations are not complete and will be updated soon) Conditional Select new tools for managing archives Folder Tools tab new search bar and Search Tab new image editing tools update function many bug fixes, stability fixes, and memory leak fixes other new features as well! Please check it out and if there are any problems, let us know. :) Also, do not forge...Player Framework by Microsoft: Player Framework for Windows 8 Metro (Preview 3): Player Framework for HTML/JavaScript and XAML/C# Metro Style Applications. Additional DownloadsIIS Smooth Streaming Client SDK for Windows 8 Microsoft PlayReady Client SDK for Metro Style Apps Release notes:Support for Windows 8 Release Preview (released 5/31/12) Advertising support (VAST, MAST, VPAID, & clips) Miscellaneous improvements and bug fixesMicrosoft Ajax Minifier: Microsoft Ajax Minifier 4.54: Fix for issue #18161: pretty-printing CSS @media rule throws an exception due to mismatched Indent/Unindent pair.Silverlight Toolkit: Silverlight 5 Toolkit Source - May 2012: Source code for December 2011 Silverlight 5 Toolkit release.Windows 8 Metro RSS Reader: RSS Reader release 6: Changed background and foreground colors Used VariableSizeGrid layout to wrap blog posts with images Sort items with Images first, text-only last Enabled Caching to improve navigation between framesJson.NET: Json.NET 4.5 Release 6: New feature - Added IgnoreDataMemberAttribute support New feature - Added GetResolvedPropertyName to DefaultContractResolver New feature - Added CheckAdditionalContent to JsonSerializer Change - Metro build now always uses late bound reflection Change - JsonTextReader no longer returns no content after consecutive underlying content read failures Fix - Fixed bad JSON in an array with error handling creating an infinite loop Fix - Fixed deserializing objects with a non-default cons...DotNetNuke® Community Edition CMS: 06.02.00: Major Highlights Fixed issue in the Site Settings when single quotes were being treated as escape characters Fixed issue loading the Mobile Premium Data after upgrading from CE to PE Fixed errors logged when updating folder provider settings Fixed the order of the mobile device capabilities in the Site Redirection Management UI The User Profile page was completely rebuilt. We needed User Profiles to have multiple child pages. This would allow for the most flexibility by still f...New ProjectsDish: ????? ???????? ??? ??.DRESSCOLLECTION: THIS IS A MVC APPLICAITON WHICH HELPS IN CREATING RANGE OF CLOTH AND DRESS COLLECTION TO CHOOSE AND BUY.FlowTasks: FlowTasks is a framework to develop human and business workflowGroup3.ERP.Roleadministration: Software zum generieren von RollendefinitionenHierarchical Pages Orchard Module: Creates a Hierarchical Page content type that does everything the built-in Page type does, but items can also contain other pages (and thus are containable by other pages too).hot24.vn: is first my project, it very cu chuoi.Household Manager: fcsdvsdvsdcdLabView interface for windows HPC: This project is a prototype library that attempts to integrate in the same enviroment the Data Acquisition and the Data Analysis systems. The library is a collection of LabVIEW Virtual Instruments that permts the job submission to a Windows HPC cluster. Jobs results can be easaly collected in order to perform actions via the DAQ control. Full documentation and examples are included.markgroves.us: Hello this is the blog template for http://markgroves.us. MostrarDireccion: Muestra la Direccion donde Reside cada personaMSPTH2012: This project is for MSPTH2012. Pattern Rolling File Appender for log4net: Appender for log4net that is combination of PatternFileAppender and RollingFileAppenderPowershell By Example: The vision of Powershell By Example is to give those interested in Powershell the chance to learn Powershell scripting by example with the goal of empowering them to use Powershell to maintain their own Windows environments. Practica Cuarto A: proyecto bakanProvidence: Providence is an application meant to capture audio, video, and screen-shots for various purposes.Proyecto T2: Tarea 2 - aprendiendo a utilizar la herramientaServer Config Tools: ??? ?????? IIS ?????SharePoint Scheduling Assistant: Scheduling assistant built for schools and universities. Works with out-of-the-box list and involves no custom workflows.Steam Group Players: This tool is meant to allow access to Steam community groups with the ability to sort group members according to hours spent playing specific games (as well as overall play time). The reason for starting this project was to allow a "player of the week"-selection that is slightly more complex than picking one by random or just by total hours played (recently).t2belenlm4c: Ana Belen LandaTaskLogger: Handy little pop-up that allows you to track time spent on project tasks. Can be used to generate timesheets.TechnicBlog: ????TPL DataFlow Debugger Visualizer: Graphic debugger visualizer to TPL DataFlow networks enable to see live state of blocks and relations Compatible with VS 2012 RC VsDoc2JsDoc: The goal of this project is to convert VSDoc JavaScript comments of JayData classes to JSDoc comment format. Using this tool you can generate the API reference of your JayData components and keep your JavaScript documentation up-to-date.WorkOutTimer: WorkOutTimer This little tool provides an easy to use timer for your workouts, trainings, and more... It has two time period, one for working, and one to be cool! By default work time is set to 2 minutes, cool time is set to 1minute (Kick boxing settings), but you can set up each period time as you want. You can hang up, restart, or reset time. It offers a high visibility timer. It also counts rounds. So have great workout! If you use it and you think it’s cool for y...XLIFF Editor: This is an attempt at making an open source XLIFF editor for Windows. I am using the Open Language Tools Editor as the primary source for the ideas of the XLIFF Editor. I am new to C# so this is is for me an ambitious learning and hopefull succesfull project. Any help in positive criticism will be looked at gratefully. xNet: xNet - a class library for .NET Framework, which includes: - Classes for work with proxy servers: HTTP, Socks4 (and), Socks5. - Classes for work with HTTP 1.0/1.1 protocol: keep-alive, gzip, deflate, chunked, SSL, proxies and more. - Classes for work with multithreading: _a multithreaded bypassing the collection, asynchronous events and more_. - Classes helpers that extend standard classes .NET Framework: FileHelper, DirectoryHelper, StringHelper, XmlHelper, BitHelper and others.?????? «??????????? ??????»: ??????????? ??????????: description

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• Javascript top variable in IE8

  - by Jim Rootham

  I am trying to reference a javascript function in a .js file loaded in my main page from an iframe using the 'top' variable. It works in FF, Safari, and IE6 but not in IE8. The snippet is (assigned to onmouseover): top.set_image(this, 'images/login_h.png') Where set_image is my function. The error is "Object does not support this function" Also, I have been looking for the definition of top. I can't find it in the ECMAScript specification or the w3schools site and Google is unhelpful (who'da thunk top was a common word?).

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• Confusion regarding laziness

  - by Abhinav Kaushik

  I have a function myLength = foldl (\ x _ -> x + 1) 0 which fails with stack overflow with input around 10^6 elements (myLength [1..1000000] fails). I believe that is due to the thunk build up since when I replace foldl with foldl', it works. So far so good. But now I have another function to reverse a list : myReverse = foldl (\ acc x -> x : acc) [] which uses the lazy version foldl (instead of foldl') When I do myLength . myReverse $ [1.1000000]. This time it works fine. I fail to understand why foldl works for the later case and not for former?

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• How do laziness and I/O work together in Haskell?

  - by Bill

  I'm trying to get a deeper understanding of laziness in Haskell. I was imagining the following snippet today: data Image = Image { name :: String, pixels :: String } image :: String -> IO Image image path = Image path <$> readFile path The appeal here is that I could simply create an Image instance and pass it around; if I need the image data it would be read lazily - if not, the time and memory cost of reading the file would be avoided: main = do image <- image "file" putStrLn $ length $ pixels image But is that how it actually works? How is laziness compatible with IO? Will readFile be called regardless of whether I access pixels image or will the runtime leave that thunk unevaluated if I never refer to it? If the image is indeed read lazily, then isn't it possible I/O actions could occur out of order? For example, what if immediately after calling image I delete the file? Now the putStrLn call will find nothing when it tries to read.

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• Five Fake Sounds Engineered to Make Your Feel Better [Science]

  - by Jason Fitzpatrick

  As objects in our environment (like cars, ATMs, and phones) have grown lighter and quieter scientists have been carefully engineering their sounds so that they continue to sound like we expect them to. Read on to see how. At the design blog Humans Invent they share five interesting ways that the world around us is being engineered so it sounds the way we expect it to. They start with the example of the car door. Years ago cars were almost entirely steel, the doors were weighty, and when you slammed them it sounded like one big hunk of steel locking into another big hunk of steel (which, in fact, it was). Newer cars are lighter but people still crave that substantial clunk. Humans Invent highlights the effect of consumer desire: A car door is essentially a hollow shell with parts placed inside it. Without careful design the door frame amplifies the rattling of mechanisms inside. Car companies know that if buyers don’t get a satisfying thud when they close the door, it dents their confidence in the entire vehicle. To produce the ideal clunk, car doors are designed to minimise the amount of high frequencies produced (we associate them with fragility and weakness) and emphasise low, bass-heavy frequencies that suggest solidity. The effect is achieved in a range of different ways – car companies have piled up hundreds of patents on the subject – but usually involves some form of dampener fitted in the door cavity. Locking mechanisms are also tailored to produce the right sort of click and the way seals make contact is precisely controlled. On average it takes 1.8 seconds to close a car door but in that time you’re witnessing a strange kind of symphony composed by engineers and designers whose goal is to reassure you that its rock solid. They mention lock mechanisms, something you may never have thought about. A friend of mine had a Ford Focus some years ago and that particular model had electric locks that, instead of giving a satisfying thunk or solid click, made this horrible gates-of-the-prison-buzzing sound that was completely unnerving. Hit up the link below to see how sounds are engineered for car doors, electric motors, ATM machines, and more. 5 Fake Sounds Designed to Help Humans [Humans Invent via Boing Boing] How To Easily Access Your Home Network From Anywhere With DDNSHow To Recover After Your Email Password Is CompromisedHow to Clean Your Filthy Keyboard in the Dishwasher (Without Ruining it)

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• RIM's current BB7 developer toolset is a joke

  - by mbrit

  tl;dr - RIM's current developer toolset is not fit for purpose.Background to this is that I'm currently working on a PhoneGap/Cordova project for a client that has to run on BlackBerry. The tooling is so ridiculous to use that even though I had a gentle dig at them in a Guardian piece it's worth having a more full-on attack.At the moment, RIM's pitch is that apps are built for the current BBOS7 devices using WebWorks. This is an HTML-based toolset. Essentially a browser is spun up in a native app container and your app is powered by JavaScript. Specific JavaScript libraries exist that thunk down to native capabilities no the device. I happen to use PhoneCap/Cordova in combination with this.The tooling is non-existent. I'm using TextMate, Ant, and Terminal to develop the app. There's no "console.log" output, and no debugging. The only way to instrument the app is to put "alert" calls in your code.Apart from the fact that that's *not* fine in 2012, how about this… every time you deploy a new app to the device, the device has to reboot. This process takes six minutes on a relatively modern BlackBerry device. How about this as well - in order to get a file into the package it has to be signed. My small app over here has 100 different files (75 or so generated). Signing doesn't happen locally, it happens on RIM's servers in Waterloo. Thus whenever you deploy the app you have this utility have to call RIM's servers 100 times. More to the point, sometimes during the day these servers have "micro-downtime" moments where they're unreachable for five or ten minutes, normally two or three times a day. Oh yes, you'll also get an email sent to you per signing on success or failure. 100 inbound emails, per deployment.(I started this post at the beginning of one of these cycles, by the way. That's how long it takes to build and deploy *once*. By the way, the change I made didn't work.)To clarify:* Change the script,* Build it using Ant,* Ant will spin up a Java app that talks to RIM's servers to sign it.* Receive 100 emails, assuming the server is up.* App deployed - takes about 30 seconds.* BlackBerry device restarts - takes about six minutes.* Find and open the app. Go through security prompts.* Test the app, with no "console.log" output and no debugger."Why not use the simulator?" I hear you ask. Well, apart from the fact that the simulator refused to reach any network service over HTTPS that I happen to own? (Some people suggest changing DNS settings for this known issue.) Admittedly, the simulator does show you console.log, but you still have the "six minute" restart issue on the simulator.Developers will understand this problem. Breaking concentration for six-plus minutes every time you want to deploy an app turns developing into a nightmare. Combining that with no worthy debugging tools turns the toolset into a joke.

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• CUPS causes printer to click and doesn't print

  - by Pez Cuckow

  I'm suffering a strange problem with my Cannon iP4850 when trying to use CUPS on a Raspberry Pi (this is not RPi specific, please do not vote to move it). When I plug the printer into my Laptop (OSX) or my Desktop W7 it identifies as a iP4800 and prints perfectly. So I plug it into the Pi (running debian), set it up in CUPS enable sharing and can now see the iP4800 series shared on the network. However if I print to it (using AirPrint etc...); the file gets to CUPS safely (shows in the queue) but when it tries to print the printer clicks (like a loud thunk) 3/4 times and then gives in, with a double amber flashing light. In cups it shows as job completed. Do you know why using the pi and cups would cause what appears to be a hardware fault and what I can do to fix the problem or to provide further debug info? Thanks for your time! Description: Canon iP4800 series Location: Lounge Driver: Canon PIXMA iP4800 - CUPS+Gutenprint v5.2.9 (color, 2-sided printing) Connection: usb://Canon/iP4800%20series?serial=2239B2 Note: I've tried deleting and re-adding the printer to the Laptop, Desktop and PI and the results are always the same Log for plugging in printer and printing (attempting to) something until the printer turned off again pi@pezpi /var/log $ dmesg [ 7284.176336] usb 1-1.2: new high speed USB device number 8 using dwc_otg [ 7284.279703] usb 1-1.2: New USB device found, idVendor=04a9, idProduct=10d5 [ 7284.279750] usb 1-1.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 7284.279771] usb 1-1.2: Product: iP4800 series [ 7284.279786] usb 1-1.2: Manufacturer: Canon [ 7284.279800] usb 1-1.2: SerialNumber: 2239B2 Setting cups to verbose: Change loglevel in cupsd.conf to debug (or debug2) pi@pezpi /var/log $ sudo vim /etc/cups/cupsd.conf pi@pezpi /var/log $ sudo /etc/init.d/cups restart [ ok ] Restarting Common Unix Printing System: cupsd. pi@pezpi /var/log $ Log from $ /var/log/cups/error_log is at http://pastebin.com/7VZMRMrG (too large to post here) The log contains - in order (deleted the log and then did the beneath) Restarting the cups server Attempting to print a test page x2 Printing from 192.168.1.90 via AirPrint Printing from 192.168.1.90 via Network Print Turning the printer off and on again

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• Cheap desktop computer in 19" rack-mountable form-factor?

  - by Alex Basson

  I'm a high school teacher at a small private school. As of this year, we have SMARTBoards in every classroom (though I've had one in the class I share for two years now). The classrooms themselves don't have computers in them, so we teachers bring our laptops to class and connect them to the boards. This has several disadvantages: This takes a few minutes while we wait for the board to boot up and then orient the board to our individual laptop -- we have to do this every time b/c different teachers have different laptops requiring different orientations. This isn't ideal because when you only have 43 minutes per class period, waiting five minutes just to get started is a real waste. Carrying your laptop to class doesn't sound so bad until you consider that we're also carrying textbooks and piles of student papers, and we're carrying it all through crowded high school hallways. More than one laptop has fallen THUNK to the floor, with dire consequences. We feel we could eliminate the need to use our laptops with the SMARTBoards if we had a dedicated computer in each classroom hooked up to the board at all times. Each board set-up is connected to a podium with a standard 19" rack in it, currently housing a power supply and DVD player. There're plenty of rack spaces available. So I'm thinking: maybe we could get some inexpensive computers in a 19" rack-mountable form factor, install them in the podiums, and connect them to the boards on a permanent basis. Any suggestions?

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• Poor LLVM JIT performance

  - by Paul J. Lucas

  I have a legacy C++ application that constructs a tree of C++ objects. I want to use LLVM to call class constructors to create said tree. The generated LLVM code is fairly straight-forward and looks repeated sequences of: ; ... %11 = getelementptr [11 x i8*]* %Value_array1, i64 0, i64 1 %12 = call i8* @T_string_M_new_A_2Pv(i8* %heap, i8* getelementptr inbounds ([10 x i8]* @0, i64 0, i64 0)) %13 = call i8* @T_QueryLoc_M_new_A_2Pv4i(i8* %heap, i8* %12, i32 1, i32 1, i32 4, i32 5) %14 = call i8* @T_GlobalEnvironment_M_getItemFactory_A_Pv(i8* %heap) %15 = call i8* @T_xs_integer_M_new_A_Pvl(i8* %heap, i64 2) %16 = call i8* @T_ItemFactory_M_createInteger_A_3Pv(i8* %heap, i8* %14, i8* %15) %17 = call i8* @T_SingletonIterator_M_new_A_4Pv(i8* %heap, i8* %2, i8* %13, i8* %16) store i8* %17, i8** %11, align 8 ; ... Where each T_ function is a C "thunk" that calls some C++ constructor, e.g.: void* T_string_M_new_A_2Pv( void *v_value ) { string *const value = static_cast<string*>( v_value ); return new string( value ); } The thunks are necessary, of course, because LLVM knows nothing about C++. The T_ functions are added to the ExecutionEngine in use via ExecutionEngine::addGlobalMapping(). When this code is JIT'd, the performance of the JIT'ing itself is very poor. I've generated a call-graph using kcachegrind. I don't understand all the numbers (and this PDF seems not to include commas where it should), but if you look at the left fork, the bottom two ovals, Schedule... is called 16K times and setHeightToAtLeas... is called 37K times. On the right fork, RAGreed... is called 35K times. Those are far too many calls to anything for what's mostly a simple sequence of call LLVM instructions. Something seems horribly wrong. Any ideas on how to improve the performance of the JIT'ing?

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• The design of a generic data synchronizer, or, an [object] that does [actions] with the aid of [helpers]

  - by acheong87

  I'd like to create a generic data-source "synchronizer," where data-source "types" may include MySQL databases, Google Spreadsheets documents, CSV files, among others. I've been trying to figure out how to structure this in terms of classes and interfaces, keeping in mind (what I've read about) composition vs. inheritance and is-a vs. has-a, but each route I go down seems to violate some principle. For simplicity, assume that all data-sources have a header-row-plus-data-rows format. For example, assume that the first rows of Google Spreadsheets documents and CSV files will have column headers, a.k.a. "fields" (to parallel database fields). Also, eventually, I would like to implement this in PHP, but avoiding language-specific discussion would probably be more productive. Here's an overview of what I've tried. Part 1/4: ISyncable class CMySQL implements ISyncable GetFields() // sql query, pdo statement, whatever AddFields() RemFields() ... _dbh class CGoogleSpreadsheets implements ISyncable GetFields() // zend gdata api AddFields() RemFields() ... _spreadsheetKey _worksheetId class CCsvFile implements ISyncable GetFields() // read from buffer AddFields() RemFields() ... _buffer interface ISyncable GetFields() AddFields($field1, $field2, ...) RemFields($field1, $field2, ...) ... CanAddFields() // maybe the spreadsheet is locked for write, or CanRemFields() // maybe no permission to alter a database table ... AddRow() ModRow() RemRow() ... Open() Close() ... First Question: Does it make sense to use an interface, as above? Part 2/4: CSyncer Next, the thing that does the syncing. class CSyncer __construct(ISyncable $A, ISyncable $B) Push() // sync A to B Pull() // sync B to A Sync() // Push() and Pull() only differ in direction; factor. // Sync()'s job is to make sure that the fields on each side // match, to add fields where appropriate and possible, to // account for different column-orderings, etc., and of // course, to add and remove rows as necessary to sync. ... _A _B Second Question: Does it make sense to define such a class, or am I treading dangerously close to the "Kingdom of Nouns"? Part 3/4: CTranslator? ITranslator? Now, here's where I actually get lost, assuming the above is passable. Sometimes, two ISyncables speak different "dialects." For example, believe it or not, Google Spreadsheets (accessed through the Google Data API "list feed") returns column headers lower-cased and stripped of all spaces and symbols! That is, sys_TIMESTAMP is systimestamp, as far as my code can tell. (Yes, I am aware that the "cell feed" does not strip the name so; however cell-by-cell manipulation is too slow for what I'm doing.) One can imagine other hypothetical examples. Perhaps even the data itself can be in different "dialects." But let's take it as given for now, and not argue this if possible. Third Question: How would you implement "translation"? Note: Taking all this as an exercise, I'm more interested in the "idealized" design, rather than the practical one. (God knows that shipped sailed when I began this project.) Part 4/4: Further Thought Here's my train of thought to demonstrate I've thunk, albeit unfruitfully: First, I thought, primitively, "I'll just modify CMySQL::GetFields() to lower-case and strip field names so they're compatible with Google Spreadsheets." But of course, then my class should really be called, CMySQLForGoogleSpreadsheets, and that can't be right. So, the thing which translates must exist outside of an ISyncable implementor. And surely it can't be right to make each translation a method in CSyncer. If it exists outside of both ISyncable and CSyncer, then what is it? (Is it even an "it"?) Is it an abstract class, i.e. abstract CTranslator? Is it an interface, since a translator only does, not has, i.e. interface ITranslator? Does it even require instantiation? e.g. If it's an ITranslator, then should its translation methods be static? (I learned what "late static binding" meant, today.) And, dear God, whatever it is, how should a CSyncer use it? Does it "have" it? Is it, "it"? Who am I? ...am I, "I"? I've attempted to break up the question into sub-questions, but essentially my question is singular: How does one implement an object A that conceptually "links" (has) two objects b1 and b2 that share a common interface B, where certain pairs of b1 and b2 require a helper, e.g. a translator, to be handled by A? Something tells me that I've overcomplicated this design, or violated a principle much higher up. Thank you all very much for your time and any advice you can provide.

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• Why does Scala apply thunks automatically, sometimes?

  - by Anonymouse

  At just after 2:40 in ShadowofCatron's Scala Tutorial 3 video, it's pointed out that the parentheses following the name of a thunk are optional. "Buh?" said my functional programming brain, since the value of a function and the value it evaluates to when applied are completely different things. So I wrote the following to try this out. My thought process is described in the comments. object Main { var counter: Int = 10 def f(): Int = { counter = counter + 1; counter } def runThunk(t: () => Int): Int = { t() } def main(args: Array[String]): Unit = { val a = f() // I expect this to mean "apply f to no args" println(a) // and apparently it does val b = f // I expect this to mean "the value f", a function value println(b) // but it's the value it evaluates to when applied to no args println(b) // and the evaluation happens immediately, not in the call runThunk(b) // This is an error: it's not println doing something funny runThunk(f) // Not an error: seems to be val doing something funny } }   To be clear about the problem, this Scheme program (and the console dump which follows) shows what I expected the Scala program to do. (define counter (list 10)) (define f (lambda () (set-car! counter (+ (car counter) 1)) (car counter))) (define runThunk (lambda (t) (t))) (define main (lambda args (let ((a (f)) (b f)) (display a) (newline) (display b) (newline) (display b) (newline) (runThunk b) (runThunk f)))) > (main) 11 #<procedure:f> #<procedure:f> 13   After coming to this site to ask about this, I came across this answer which told me how to fix the above Scala program: val b = f _ // Hey Scala, I mean f, not f() But the underscore 'hint' is only needed sometimes. When I call runThunk(f), no hint is required. But when I 'alias' f to b with a val then apply it, it doesn't work: the evaluation happens in the val; and even lazy val works this way, so it's not the point of evaluation causing this behaviour.   That all leaves me with the question: Why does Scala sometimes automatically apply thunks when evaluating them? Is it, as I suspect, type inference? And if so, shouldn't a type system stay out of the language's semantics? Is this a good idea? Do Scala programmers apply thunks rather than refer to their values so much more often that making the parens optional is better overall? Examples written using Scala 2.8.0RC3, DrScheme 4.0.1 in R5RS.

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• Developing Schema Compare for Oracle (Part 2): Dependencies

  - by Simon Cooper

  In developing Schema Compare for Oracle, one of the issues we came across was the size of the databases. As detailed in my last blog post, we had to allow schema pre-filtering due to the number of objects in a standard Oracle database. Unfortunately, this leads to some quite tricky situations regarding object dependencies. This post explains how we deal with these dependencies. 1. Cross-schema dependencies Say, in the following database, you're populating SchemaA, and synchronizing SchemaA.Table1: SOURCE   TARGET CREATE TABLE SchemaA.Table1 ( Col1 NUMBER REFERENCES SchemaB.Table1(Col1));   CREATE TABLE SchemaA.Table1 ( Col1 VARCHAR2(100) REFERENCES SchemaB.Table1(Col1)); CREATE TABLE SchemaB.Table1 ( Col1 NUMBER PRIMARY KEY);   CREATE TABLE SchemaB.Table1 ( Col1 VARCHAR2(100) PRIMARY KEY); We need to do a rebuild of SchemaA.Table1 to change Col1 from a VARCHAR2(100) to a NUMBER. This consists of: Creating a table with the new schema Inserting data from the old table to the new table, with appropriate conversion functions (in this case, TO_NUMBER) Dropping the old table Rename new table to same name as old table Unfortunately, in this situation, the rebuild will fail at step 1, as we're trying to create a NUMBER column with a foreign key reference to a VARCHAR2(100) column. As we're only populating SchemaA, the naive implementation of the object population prefiltering (sticking a WHERE owner = 'SCHEMAA' on all the data dictionary queries) will generate an incorrect sync script. What we actually have to do is: Drop foreign key constraint on SchemaA.Table1 Rebuild SchemaB.Table1 Rebuild SchemaA.Table1, adding the foreign key constraint to the new table This means that in order to generate a correct synchronization script for SchemaA.Table1 we have to know what SchemaB.Table1 is, and that it also needs to be rebuilt to successfully rebuild SchemaA.Table1. SchemaB isn't the schema that the user wants to synchronize, but we still have to load the table and column information for SchemaB.Table1 the same way as any table in SchemaA. Fortunately, Oracle provides (mostly) complete dependency information in the dictionary views. Before we actually read the information on all the tables and columns in the database, we can get dependency information on all the objects that are either pointed at by objects in the schemas we’re populating, or point to objects in the schemas we’re populating (think about what would happen if SchemaB was being explicitly populated instead), with a suitable query on all_constraints (for foreign key relationships) and all_dependencies (for most other types of dependencies eg a function using another function). The extra objects found can then be included in the actual object population, and the sync wizard then has enough information to figure out the right thing to do when we get to actually synchronize the objects. Unfortunately, this isn’t enough. 2. Dependency chains The solution above will only get the immediate dependencies of objects in populated schemas. What if there’s a chain of dependencies? A.tbl1 -> B.tbl1 -> C.tbl1 -> D.tbl1 If we’re only populating SchemaA, the implementation above will only include B.tbl1 in the dependent objects list, whereas we might need to know about C.tbl1 and D.tbl1 as well, in order to ensure a modification on A.tbl1 can succeed. What we actually need is a graph traversal on the dependency graph that all_dependencies represents. Fortunately, we don’t have to read all the database dependency information from the server and run the graph traversal on the client computer, as Oracle provides a method of doing this in SQL – CONNECT BY. So, we can put all the dependencies we want to include together in big bag with UNION ALL, then run a SELECT ... CONNECT BY on it, starting with objects in the schema we’re populating. We should end up with all the objects that might be affected by modifications in the initial schema we’re populating. Good solution? Well, no. For one thing, it’s sloooooow. all_dependencies, on my test databases, has got over 110,000 rows in it, and the entire query, for which Oracle was creating a temporary table to hold the big bag of graph edges, was often taking upwards of two minutes. This is too long, and would only get worse for large databases. But it had some more fundamental problems than just performance. 3. Comparison dependencies Consider the following schema: SOURCE   TARGET CREATE TABLE SchemaA.Table1 ( Col1 NUMBER REFERENCES SchemaB.Table1(col1));   CREATE TABLE SchemaA.Table1 ( Col1 VARCHAR2(100)); CREATE TABLE SchemaB.Table1 ( Col1 NUMBER PRIMARY KEY);   CREATE TABLE SchemaB.Table1 ( Col1 VARCHAR2(100)); What will happen if we used the dependency algorithm above on the source & target database? Well, SchemaA.Table1 has a foreign key reference to SchemaB.Table1, so that will be included in the source database population. On the target, SchemaA.Table1 has no such reference. Therefore SchemaB.Table1 will not be included in the target database population. In the resulting comparison of the two objects models, what you will end up with is: SOURCE  TARGET SchemaA.Table1 -> SchemaA.Table1 SchemaB.Table1 -> (no object exists) When this comparison is synchronized, we will see that SchemaB.Table1 does not exist, so we will try the following sequence of actions: Create SchemaB.Table1 Rebuild SchemaA.Table1, with foreign key to SchemaB.Table1 Oops. Because the dependencies are only followed within a single database, we’ve tried to create an object that already exists. To fix this we can include any objects found as dependencies in the source or target databases in the object population of both databases. SchemaB.Table1 will then be included in the target database population, and we won’t try and create objects that already exist. All good? Well, consider the following schema (again, only explicitly populating SchemaA, and synchronizing SchemaA.Table1): SOURCE   TARGET CREATE TABLE SchemaA.Table1 ( Col1 NUMBER REFERENCES SchemaB.Table1(col1));   CREATE TABLE SchemaA.Table1 ( Col1 VARCHAR2(100)); CREATE TABLE SchemaB.Table1 ( Col1 NUMBER PRIMARY KEY);   CREATE TABLE SchemaB.Table1 ( Col1 VARCHAR2(100) PRIMARY KEY); CREATE TABLE SchemaC.Table1 ( Col1 NUMBER);   CREATE TABLE SchemaC.Table1 ( Col1 VARCHAR2(100) REFERENCES SchemaB.Table1); Although we’re now including SchemaB.Table1 on both sides of the comparison, there’s a third table (SchemaC.Table1) that we don’t know about that will cause the rebuild of SchemaB.Table1 to fail if we try and synchronize SchemaA.Table1. That’s because we’re only running the dependency query on the schemas we’re explicitly populating; to solve this issue, we would have to run the dependency query again, but this time starting the graph traversal from the objects found in the other database. Furthermore, this dependency chain could be arbitrarily extended.This leads us to the following algorithm for finding all the dependencies of a comparison: Find initial dependencies of schemas the user has selected to compare on the source and target Include these objects in both the source and target object populations Run the dependency query on the source, starting with the objects found as dependents on the target, and vice versa Repeat 2 & 3 until no more objects are found For the schema above, this will result in the following sequence of actions: Find initial dependenciesSchemaA.Table1 -> SchemaB.Table1 found on sourceNo objects found on target Include objects in both source and targetSchemaB.Table1 included in source and target Run dependency query, starting with found objectsNo objects to start with on sourceSchemaB.Table1 -> SchemaC.Table1 found on target Include objects in both source and targetSchemaC.Table1 included in source and target Run dependency query on found objectsNo objects found in sourceNo objects to start with in target Stop This will ensure that we include all the necessary objects to make any synchronization work. However, there is still the issue of query performance; the CONNECT BY on the entire database dependency graph is still too slow. After much sitting down and drawing complicated diagrams, we decided to move the graph traversal algorithm from the server onto the client (which turned out to run much faster on the client than on the server); and to ensure we don’t read the entire dependency graph onto the client we also pull the graph across in bits – we start off with dependency edges involving schemas selected for explicit population, and whenever the graph traversal comes across a dependency reference to a schema we don’t yet know about a thunk is hit that pulls in the dependency information for that schema from the database. We continue passing more dependent objects back and forth between the source and target until no more dependency references are found. This gives us the list of all the extra objects to populate in the source and target, and object population can then proceed. 4. Object blacklists and fast dependencies When we tested this solution, we were puzzled in that in some of our databases most of the system schemas (WMSYS, ORDSYS, EXFSYS, XDB, etc) were being pulled in, and this was increasing the database registration and comparison time quite significantly. After debugging, we discovered that the culprits were database tables that used one of the Oracle PL/SQL types (eg the SDO_GEOMETRY spatial type). These were creating a dependency chain from the database tables we were populating to the system schemas, and hence pulling in most of the system objects in that schema. To solve this we introduced blacklists of objects we wouldn’t follow any dependency chain through. As well as the Oracle-supplied PL/SQL types (MDSYS.SDO_GEOMETRY, ORDSYS.SI_COLOR, among others) we also decided to blacklist the entire PUBLIC and SYS schemas, as any references to those would likely lead to a blow up in the dependency graph that would massively increase the database registration time, and could result in the client running out of memory. Even with these improvements, each dependency query was taking upwards of a minute. We discovered from Oracle execution plans that there were some columns, with dependency information we required, that were querying system tables with no indexes on them! To cut a long story short, running the following query: SELECT * FROM all_tab_cols WHERE data_type_owner = ‘XDB’; results in a full table scan of the SYS.COL$ system table! This single clause was responsible for over half the execution time of the dependency query. Hence, the ‘Ignore slow dependencies’ option was born – not querying this and a couple of similar clauses to drastically speed up the dependency query execution time, at the expense of producing incorrect sync scripts in rare edge cases. Needless to say, along with the sync script action ordering, the dependency code in the database registration is one of the most complicated and most rewritten parts of the Schema Compare for Oracle engine. The beta of Schema Compare for Oracle is out now; if you find a bug in it, please do tell us so we can get it fixed!

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