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  • putting <%=yield %> in a partial for ajax jquery calls

    - by odpogn
    I'm trying to make the "home" link in my <%= render 'layouts/header' %> do an ajax/jquery call to change the <%= yield %> in a partial inside my content div. all i get are blanks in the view.. <%= yield %> works fine when put in a partial without ajax, but it doesn't display anything when using ajax... can yield not be used this way? all I'm really looking for is the ability to click on my sites navigation links without having to reload the entire page... my application.html.erb file looks like so: <head> $(function() { $("#home").live("click", function() { $.get(this.href, null, null, "script"); return false; }); }); </head> <body> <div id="container"> <%= render 'layouts/header' %> <div id="content"> <%= render 'layouts/content' %> </div> <%= render 'layouts/footer' %> </div> </body> my <%= render 'layouts/header' %> contains: <%= link_to "Home", root_path, :id => "home" %> my <%= render 'layouts/content' %> only contains: <%= yield %> home.js.erb $("#content").html("<%= escape_javascript(render("layouts/content")) %>");

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  • Autodiscovery for inclusion tags

    - by Ludwik Trammer
    The title may be a little confusing, but I don't know how else to call it. I would like to create a Django project with a large set of applications you could arbitrary turn on or off using INSTALLED_APPS option in settings.py (you would obviously also need to edit urls.py and run syncdb). After being turned on an app should be able to automatically: Register it's content in site-wide search. Luckily django-haystack has this built-in, so it's not a problem. Register cron jobs. django-cron does exactly that. Not a problem. Register a widget that should be displayed on the homepage. The homepage should include a list of boxes with widgets form different applications. I thought about inclusion tags, because you can put them anywhere on a page and they control both content and presentation. The problem is I don't know how to automatically get a list of inclusion tags provided by my applications, and display them one by one on a homepage. I need a way to register them somehow, and then display all registered tags.

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  • how to play an audio soundclip when a nib is loaded - welcome screen - xcode

    - by Pavan
    I would like to do the following two things: 1) I would like to play an audio file qhen a nib is loaded 2) After that i would like to switch views when the audio file has finished playing. This will be easy as i just need to call the event that initiates the change of view by using the delegate method -(void) audioPlayerDidFinishPlaying{ //code to change view } I dont know how to to play the audio file when a nib is loaded. Using the AVFoundation framework, I tried doing the following after setting up the audio player and the variables associated with it in the appropriate places i wrote the following: - (void)viewDidLoad { [super viewDidLoad]; NSString *soundFilePath = [[NSBundle mainBundle] pathForResource: @"sound" ofType: @"mp3"]; NSURL *fileURL = [[NSURL alloc] initFileURLWithPath: soundFilePath]; AVAudioPlayer *newPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL: fileURL error:nil]; [fileURL release]; self.player = newPlayer; [newPlayer release]; [player prepareToPlay]; [player setDelegate: self]; [player play]; } Although this does not play the file as the viewdidload method gets called before the nib is shown so the audio is never played or heard. What do i need to do so that i can play the audio file AFTER the nib has loaded and is shown on the screen? can someone please help me as ive been working on this for 3 hours now. Thanks in advance.

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  • EF 4 Self Tracking Entities does not work as expected.

    - by ashraf
    I am using EF4 Self Tracking Entities (VS2010 Beta 2 CTP 2 plus new T4 generator). But when I try to update entity information it does not update to database as expected. I setup 2 service calls. one for GetResource(int id) which return a resource object. the second call is SaveResource(Resource res); here is the code. public Resource GetResource(int id) { using (var dc = new MyEntities()) { return dc.Resources.Where(d => d.ResourceId == id).SingleOrDefault(); } } public void SaveResource(Resource res) { using (var dc = new MyEntities()) { dc.Resources.ApplyChanges(res); dc.SaveChanges(); // Nothing save to database. } } //Windows Console Client Calls var res = service.GetResource(1); res.Description = "New Change"; // Not updating... service.SaveResource(res); // does not change anything. It seems to me that ChangeTracker.State is always show as "Unchanged". anything wrong in this code?

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  • MSBUILD batch targets

    - by Darthg8r
    I want to deploy an application to a list of servers. I have all of the build issues taken care of, but I'm having trouble publishing to a list of servers. I want to read the list of servers from an external file and call a target passing the name of each server in. <ItemGroup> <File Include="$(SolutionFolder)CP\Build\DenormDevServers.txt" /> </ItemGroup> <Target Name="DeployToServer" Inputs="Servers" Outputs="Nothing"> <Message Text="Deployment to server done here. Deploying to server: @(Servers)" /> </Target> <Target Name="Test"> <ReadLinesFromFile File="@(File)"> <Output TaskParameter="Lines" ItemName="Servers" /> </ReadLinesFromFile> <CallTarget Targets="DeployToServer" ContinueOnError="true"></CallTarget> </Target> I can't seem to get it to "Deploy" to each server in the list. The output looks like this: Deployment to server done here. Deploying to server: Notice there is no server name, nor is done more than once. There are 2 lines in DenormDevServers.txt

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  • Using boost asio for pub/sub style tcp in a game loop

    - by unohoo
    I have been reading through the boost asio documentation for a couple of hours now, and while I think the documentation is really great, I am still left a bit confused on how to implement the system that I need. I have to stream info, from a game engine, to a list of computers over tcp. One snag is that, unlike traditional pub/sub, the computer that does the distribution of info is actually the computer that has to connect to the subscribers as well (instead of the subscribers registering with the publisher). This is done via a config file - a list of ip's/ports along with the data that they each require. The subscribers listen, but do not know the ip of the publisher. (As a side note, I'm quite new to network programming, so maybe I'm missing something .. but it's strange that I do not find much information regarding this style of "inverted" client-server model..) I am looking for suggestions for the implementation of such a system using boost asio. Of course I have to integrate the networking into an already existing engine, so with regards to that: What would be a good way to handle messages being sent to multiple computers every frame? Use async_write, call io_service.run and then reset every frame? Would having io_service.run have its own thread be better? Or should I just use threads and use blocking writes?

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  • GWT: Populating a page from datastore using RPC is too slow

    - by Ilya Boyandin
    Is there a way to speed up the population of a page with GWT's UI elements which are generated from data loaded from the datastore? Can I avoid making the unnecessary RPC call when the page is loaded? More details about the problem I am experiencing: There is a page on which I generate a table with names and buttons for a list of entities loaded from the datastore. There is an EntryPoint for the page and in its onModuleLoad() I do something like this: final FlexTable table = new FlexTable(); rpcAsyncService.getAllCandidates(new AsyncCallback<List<Candidate>>() { public void onSuccess(List<Candidate> candidates) { int row = 0; for (Candidate person : candidates) { table.setText(row, 0, person.getName()); table.setWidget(row, 1, new ToggleButton("Yes")); table.setWidget(row, 2, new ToggleButton("No")); row++; } } ... }); This works, but takes more than 30 seconds to load the page with buttons for 300 candidates. This is unacceptable. The app is running on Google App Engine and using the app engine's datastore.

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  • Explaining the forecasts from an ARIMA model

    - by Samik R.
    I am trying to explain to myself the forecasting result from applying an ARIMA model to a time-series dataset. The data is from the M1-Competition, the series is MNB65. For quick reference, I have a google doc spreadsheet with the data. I am trying to fit the data to an ARIMA(1,0,0) model and get the forecasts. I am using R. Here are some output snippets: > arima(x, order = c(1,0,0)) Series: x ARIMA(1,0,0) with non-zero mean Call: arima(x = x, order = c(1, 0, 0)) Coefficients: ar1 intercept 0.9421 12260.298 s.e. 0.0474 202.717 > predict(arima(x, order = c(1,0,0)), n.ahead=12) $pred Time Series: Start = 53 End = 64 Frequency = 1 [1] 11757.39 11786.50 11813.92 11839.75 11864.09 11887.02 11908.62 11928.97 11948.15 11966.21 11983.23 11999.27 I have a few questions: (1) How do I explain that although the dataset shows a clear downward trend, the forecast from this model trends upward. This also happens for ARIMA(2,0,0), which is the best ARIMA fit for the data using auto.arima (forecast package) and for an ARIMA(1,0,1) model. (2) The intercept value for the ARIMA(1,0,0) model is 12260.298. Shouldn't the intercept satisfy the equation: C = mean * (1 - sum(AR coeffs)), in which case, the value should be 715.52. I must be missing something basic here. (3) This is clearly a series with non-stationary mean. Why is an AR(2) model still selected as the best model by auto.arima? Could there be an intuitive explanation? Thanks.

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  • wcf trying to set up tracing to debug, not writing to log file

    - by joey j
    here's my web.config, running a WCF service in an application on IIS7, but nothing is being written to the specified file. permission on the file has been granted for everyone. </listeners> I can add a service reference just fine. I then try to call the service from a windows app and, after a few minutes, get an error on the machine running the windows app "Client is unable to finish the security negotiation within the configured timeout (00:00:00). The current negotiation leg is 1 (00:00:00)." but absolutely nothing is written to the trace log file specified in config. Is there something else I need to do to enable tracing? thanks for your help EDIT: "sources" section now matches the section recommended here: http://msdn.microsoft.com/en-us/library/aa702726.aspx I've added the "diagnostics and the event viewer shows: "Message Logging has been turned on. Sensitive information may be logged in the clear, even if it was encrypted on the wire: for example, message bodies. Process Name: w3wp Process ID: 1784 " but the log file is still empty

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  • c++ callback syntax in a class

    - by Mr Bell
    I am trying to figure out the syntax to register a callback with this 3rd party software. I think it is probably a basic question, I just am not too familiar with c++. They have a method for registering a callback function so their code can call a function in my code when an event happens. They provided a working example that registers the callback from the main file, but I want to know how to do it when working inside a class Their method signature: smHTRegisterHeadPoseCallback(smEngineHandle engine_handle, void *user_data, smHTHeadPoseCallback callback_fun); Working example from the main file: void STDCALL receiveHeadPose(void *,smEngineHeadPoseData head_pose, smCameraVideoFrame video_frame) { ... } void main() { ... smHTRegisterHeadPoseCallback(engine_handle,0,receiveHeadPose) ... } But I want to use this from my class MyClass.h class FaceEngine { public: void STDCALL receiveFaceData(void *, smEngineFaceData face_data, smCameraVideoFrame video_frame); ... MyClass.cpp void FaceEngine::Start(void) { rc = smHTRegisterFaceDataCallback(hFaceAPIEngine,0,&FaceEngine::receiveFaceData); ... Results in this compiler error: Error 1 error C2664: 'smHTRegisterFaceDataCallback' : cannot convert parameter 3 from 'void (__stdcall FaceEngine::* )(void *,smEngineFaceData,smCameraVideoFrame)' to 'smHTFaceDataCallback' d:\stuff\programming\visual studio 2008\projects\tut02_vertices\faceengine.cpp 43 Beard If my question isn't clear please let me know how I can clarify.

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  • How do you send in the LayoutRoot into a RelayCommand via a EventToCommand?

    - by user298145
    Grid example with the trigger: <Grid x:Name="LayoutRoot" DataContext="{Binding ProjectGrid, Source={StaticResource Locator}}"> <i:Interaction.Triggers> <i:EventTrigger EventName="Loaded"> <GalaSoft_MvvmLight_Command:EventToCommand Command="{Binding LoadedCommand, Mode=OneWay}" PassEventArgsToCommand="True"/> </i:EventTrigger> </i:Interaction.Triggers> In my ViewModel I set the LoadedCommand like this: public RelayCommand<RoutedEventArgs> LoadedCommand {get;private set;} And in the ViewModel initializer I have this: public ProjectGridViewModel() { LoadedCommand = new RelayCommand<RoutedEventArgs>(e => { this.DoLoaded(e); } ); } Then, in my DoLoaded I'm trying to do this: Grid _projectGrid = null; public void DoLoaded(RoutedEventArgs e) { _projectGrid = e.OriginalSource as Grid; } You can see I'm trying to get rid of my Loaded="" in my Grid in my view, and do a RelayCommand instead. The issue is the OriginalSource brings back nothing. My loaded event is running nice this way, but I need to get the Grid in via the RoutedEventArgs it seems. I tried passing in the Grid in the EventCommand with CommandParameter="{Binding ElementName=LayoutRoot}", but this just crashes VS2010 when hitting F5 and running the project. Any ideas? Or a better way to do this? I had the Loaded event run in the views C# then call the ViewModel in the Views code-behind, but I'd like to do a nicer binding. Talking to the ViewMode in the Views code-behind feels like a hack.

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  • XSL transformation generating output from other nodes

    - by Abel Morelos
    I have the following XSL template: <xsl:template match="SOAP-ENV:Body/*[local-name()='Publisher']"> <html> <xsl:call-template name="body" /> </html> </xsl:template> The previous template generates the output I want, it's generating the tags containing the output generated by the "body" template. The issue I'm having is that before the opening tag I'm getting text output from a previous node. Not sure why this is happening since I'm not selecting these other nodes. For example: <SOAP-ENV:Header> <!-- Many child nodes here--> </SOAP-ENV:Header> <SOAP-ENV:Body> <publishParty:Publisher> <!-- Many child nodes here--> </publishParty:Publisher> </SOAP-ENV:Body> Given the previous sample XML fragment, my output would contain what I would expect of formatting the Publisher element, but I'm also getting the text nodes of the children of the SOAP-ENV:Header node. Any ideas? Thanks!

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  • Ajax UpdatePanels SetFocus issue

    - by George
    I set the AutoPostback property of a textbox to True so I can process the TextChanged event on the server and, based on what they typed in the textbox, appropriately display a message in an update panel. The problem is, when the partial screen refresh is performed, no control on the screen has focus. 99% of the time, when the text in the textbox is changed, it is because the user has tabbed forward, and so, to limit the disruption in the lost of focus, I perform a "Focus" call on teh next control in the tab sequence. For the most part, this works OK, but of course, is disputive if the user is tabbing in the reverse order or has used the mouse to set the focus to another control. In these situations, the focus would be set to the next control even though the user was trying to set focus elsewhere. OK, that sucks. Now what I consider the bigger problem with calling the focus method on the server: In IE, it works OK, but in Mozilla Firefox and Chrome, setting the focus causes a repositioning of the scroll bar, even though none is necessary because the control is already in view. I realize that I could switch to doing AJAX web service calls, but these darn Updae Panels are so convenient if used in moderation. is there anyway to use updatepanels and not have these focus/scroll issues?

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  • Bash script to insert code from one file at a specific location in another file?

    - by Kurtosis
    I have a fileA with a snippet of code, and I need a script to insert that snippet into fileB on the line after a specific pattern. I'm trying to make the accepted answer in this thread work, but it's not, and is not giving an error so not sure why not: sed -e '/pattern/r text2insert' filewithpattern Any suggestions? pattern (insert snippet on line after): def boot { also tried escaped pattern but no luck: def\ boot\ { def\ boot\ \{ fileA snippet: LiftRules.htmlProperties.default.set((r: Req) => new Html5Properties(r.userAgent)) fileB (Boot.scala): package bootstrap.liftweb import net.liftweb._ import util._ import Helpers._ import common._ import http._ import sitemap._ import Loc._ /** * A class that's instantiated early and run. It allows the application * to modify lift's environment */ class Boot { def boot { // where to search snippet LiftRules.addToPackages("code") // Build SiteMap val entries = List( Menu.i("Home") / "index", // the simple way to declare a menu // more complex because this menu allows anything in the // /static path to be visible Menu(Loc("Static", Link(List("static"), true, "/static/index"), "Static Content"))) // set the sitemap. Note if you don't want access control for // each page, just comment this line out. LiftRules.setSiteMap(SiteMap(entries:_*)) // Use jQuery 1.4 LiftRules.jsArtifacts = net.liftweb.http.js.jquery.JQuery14Artifacts //Show the spinny image when an Ajax call starts LiftRules.ajaxStart = Full(() => LiftRules.jsArtifacts.show("ajax-loader").cmd) // Make the spinny image go away when it ends LiftRules.ajaxEnd = Full(() => LiftRules.jsArtifacts.hide("ajax-loader").cmd) // Force the request to be UTF-8 LiftRules.early.append(_.setCharacterEncoding("UTF-8")) } }

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  • Jasmine testing coffeescript expect(setTimeout).toHaveBeenCalledWith

    - by Lee Quarella
    In the process of learning Jasmine, I've come to this issue. I want a basic function to run, then set a timeout to call itself again... simple stuff. class @LoopObj constructor: -> loop: (interval) -> #do some stuff setTimeout((=>@loop(interval)), interval) But I want to test to make sure the setTimeout was called with the proper args describe "loop", -> xit "does nifty things", -> it "loops at a given interval", -> my_nifty_loop = new LoopObj interval = 10 spyOn(window, "setTimeout") my_nifty_loop.loop(interval) expect(setTimeout).toHaveBeenCalledWith((-> my_nifty_loop.loop(interval)), interval) I get this error: Expected spy setTimeout to have been called with [ Function, 10 ] but was called with [ [ Function, 10 ] ] Is this because the (-> my_nifty_loop.loop(interval)) function does not equal the (=>@loop(interval)) function? Or does it have something to do with the extra square brackets around the second [ [ Function, 10 ] ]? Something else altogther? Where have I gone wrong?

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  • Issue calling superclass method in subclass constructor

    - by stormin986
    I get a NullPointerException calling a Superclass Method in Subclass Inner Class Constructor... What's the Deal? In my application's main class (subclass of Application), I have a public inner class that simply contains 3 public string objects. In the parent class I declare an object of that inner class. public class MainApplication extends Application { public class Data { public String x; public String y; public String z; } private Data data; MainApplication() { data = new Data() data.x = SuperClassMethod(); } } After I instantiate the object in the constructor, I get a runtime error when I try to assign a value in the inner class with a superclass method. Any idea what's up here?? Can you not call superclass methods in the subclass constructor? ** Edit ** Original question was about inner class member assignment in outer class constructor. Turned out the issue was with calling a superclass method in the class's constructor. It was giving me a null pointer exception. Thus, the question has changed.

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  • d2: assigning ranges/iterators to array slices

    - by modchan
    Consider following code: enum size = 16; double[size] arr1 = [...]; double[size] arr2 = [...]; process = (double x) { return (x + 1); }; arr2[] = map!(process)(arr1[]); // here I have trouble converting results of map back to my plain array. Problem applies not only to map, but also to take, repeat and all those fine tools from std.algorithm and std.range that operate on ranges. On this assignment, I get Error: cannot implicitly convert expression (map(arr1[])) of type Result to double[]. How can I evaluate range to array without using uint i = 0; foreach (x; map!(process)(arr1[])) { arr2[i] = x; i++; } ? Additionally, can someone please explain, why I must call map!(process)(arr1[]) instead of map!(process)(arr1) with static arrays? Shouldn't static arrays be compatible with dynamic for means of iteration, or I don't get something? Also, it seems that straightforward enumeration syntax foreach (index, item; sequence) does not work for ranges - are there workarounds? I guess the reason is the same as why ranges cannot be assigned to array slices.

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  • Calling delegate methods and calling selectors

    - by Crystal
    I'm new to the concept of delegates and selectors when used with notifications. So my first question is, 1) Let's say you have a button that has a delegate that implements some doWork method. If you want the same functionality that's in the method, is it 'ok' to just call that method? I didn't know if that was considered good coding practices and/or if you should do that, or do something different in getting that type of functionality. Like if that is ok architecture? 2) Similarly, with NSNotificationCenter, I see some code that posts a notification. Then there's a HandleSegmentedControl:(NSNotification *)notification method. If I want to manually have that functionality, but without pressing the segment control, is it 'ok' to just take that functionality out of that method and put it in a new method so it would look like this: Original: - (void)HandleSegmentedControl:(NSNotification *)notification { NSDictionary *dict = [userInfo notification]; // do stuff with the dictionary } New: - (void)HandleSegmentedControl:(NSNotification *)notification { NSDictionary *dict = [userInfo notification]; [self newMethod:dict]; } - (void)newMethod:(NSDictionary *)dict { // do stuff with the dictionary } - (void)myOtherMethodThatNeedsTheSameFunctionality { NSDictionary *dict = // create some dictionary [self newMethod:dict]; } Sorry if these are basic questions. I'm not sure what the best practices are for things like this and wanted to start the right way. Thanks.

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  • onSubmit returning false is not working

    - by StuckOnSubmit
    I'm completely confused ... I'd swear this was working yesterday ... I woke up this morning and all my forms stopped to work in my project. All the forms have a "onsubmit" to a function that returns false since it's an ajax call, so the form is never sent. After a lot of tests, I simplified the question to this piece of code: <html> <head> <script type="text/javascript"> function sub() { alert ("MIC!"); return false; } </script> </head> <body> <form method = "post" id = "form1" onsubmit = "return sub()"> input: <input type="text" name="input1" > <a href="#" onClick="document.getElementById('form1').submit();">button</a> </form> </body> </html> I would swear that this works perfectly, but today is nor working :D Why if I press the button the form is sent ? I know it's a total newbie question, but I'm stuck Thank you !

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  • App no longer working - any ideas

    - by hamishmcn
    I am out of ideas as to why my app has suddenly stopped working - perhaps the collective mind of the SO community can help... Background: I have a large application that has been working up until recently. Now when ever I try and run it I get the error "The application failed to initialize properly (0xc0000005)" This happens before the app gets to _tmain(). It happens in both release and debug builds. I have tried cleaning and rebuilding the projects and rebooted my PC. The call stack just shows entries for kernel32.dll and ntdll.dll The output window shows: First-chance exception at 0x00532c13 in a.exe: 0xC0000005: Access violation reading location 0xabababdb. First-chance exception at 0x7c964ed1 in a.exe: 0xC0000005: Access violation. Unhandled exception at 0x7c964ed1 in a.exe: 0xC0000005: Access violation. Any ideas? Edit: Okay - found the problem - it was dll related my app uses shared dlls a.dll and b.dll (and others) a.dll hardly every changes (and uses b.dll) b.dll was changed by another developer this morning and a.dll was not rebuilt. Depends.exe did not show any missing dlls, however a.dll no longer works because of the change to b.dll

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  • Trying to draw a dynamic rectangle in SVG

    - by Shaun
    To be more specific, here are the steps I need: onmousedown - set x and y of rect as mouse coordinates onmousemove - using the current x and y mouse coordinates calculate height and width of the rect, set these and append onmouseup - remove the rectangle, and call a function based off some calculations from the rect. Here is what I have but isn't quite working (right now I have it drawing a line to make it simpler): onmousedown: startbox(evt) function startbox(evt) { if(evt.button === 0) { x1 = evt.clientX + div.scrollLeft-5; y1 = evt.clientY + div.scrollTop-30; obj.setAttributeNS(null, "x1", x1); obj.setAttributeNS(null, "y1", y1); Root.setAttributeNS(null, "onmousemove", "updatebox(evt)"); } } onmousemove: updatebox(evt) function updatebox(evt) { if(evt.button === 0) { x2 = evt.clientX + div.scrollLeft-5; y2 = evt.clientY + div.scrollTop-30; Root.appendChild(.obj); w = Math.abs(x2-x1); h = Math.abs(y2-y1); var strokecolor; if(w>20 && h>20) { strokecolor = "green"; validbox = true; } else { strokecolor = "red"; validbox = false; } var Attr={ x2:x2, y2:y2, stroke:strokecolor } assignAttr(obj, Attr); //just loops thru adding multiple attributes } } onmouseup: endbox() function endbox(evt) { if(evt.button===0) { Root.setAttributeNS(null, "onmousemove", ""); Root.removeChild(obj); if(validbox) { //do stuff validbox = !validbox; } } } Some of my problems with this are: Its slow in Chrome making drawing the line/rect feel sluggish. It won't work two times in a row. This is the real problem that I can't fix. Any and all feedback is welcome.

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  • How do I get save (no exclamation point) semantics in an ActiveRecord transaction?

    - by James A. Rosen
    I have two models: Person and Address which I'd like to create in a transaction. That is, I want to try to create the Person and, if that succeeds, create the related Address. I would like to use save semantics (return true or false) rather than save! semantics (raise an ActiveRecord::StatementInvalid or not). This doesn't work because the user.save doesn't trigger a rollback on the transaction: class Person def save_with_address(address_options = {}) transaction do self.save address = Address.build(address_options) address.person = self address.save end end end (Changing the self.save call to an if self.save block around the rest doesn't help, because the Person save still succeeds even when the Address one fails.) And this doesn't work because it raises the ActiveRecord::StatementInvalid exception out of the transaction block without triggering an ActiveRecord::Rollback: class Person def save_with_address(address_options = {}) transaction do save! address = Address.build(address_options) address.person = self address.save! end end end The Rails documentation specifically warns against catching the ActiveRecord::StatementInvalid inside the transaction block. I guess my first question is: why isn't this transaction block... transacting on both saves?

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  • What does this structure actually do?

    - by LGTrader
    I found this structure code in a Julia Set example from a book on CUDA. I'm a newbie C programmer and cannot get my head around what it's doing, nor have I found the right thing to read on the web to clear it up. Here's the structure: struct cuComplex { float r; float i; cuComplex( float a, float b ) : r(a), i(b) {} float magnitude2( void ) { return r * r + i * i; } cuComplex operator*(const cuComplex& a) { return cuComplex(r*a.r - i*a.i, i*a.r + r*a.i); } cuComplex operator+(const cuComplex& a) { return cuComplex(r+a.r, i+a.i); } }; and it's called very simply like this: cuComplex c(-0.8, 0.156); cuComplex a(jx, jy); int i = 0; for (i=0; i<200; i++) { a = a * a + c; if (a.magnitude2() > 1000) return 0; } return 1; So, the code did what? Defined something of structure type 'cuComplex' giving the real and imaginary parts of a number. (-0.8 & 0.156) What is getting returned? (Or placed in the structure?) How do I work through the logic of the operator stuff in the struct to understand what is actually calculated and held there? I think that it's probably doing recursive calls back into the stucture float magnitude2 (void) { return return r * r + i * i; } probably calls the '*' operator for r and again for i, and then the results of those two operations call the '+' operator? Is this correct and what gets returned at each step? Just plain confused. Thanks!

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  • Are functional programming languages good for practical tasks?

    - by Clueless
    It seems to me from my experimenting with Haskell, Erlang and Scheme that functional programming languages are a fantastic way to answer scientific questions. For example, taking a small set of data and performing some extensive analysis on it to return a significant answer. It's great for working through some tough Project Euler questions or trying out the Google Code Jam in an original way. At the same time it seems that by their very nature, they are more suited to finding analytical solutions than actually performing practical tasks. I noticed this most strongly in Haskell, where everything is evaluated lazily and your whole program boils down to one giant analytical solution for some given data that you either hard-code into the program or tack on messily through Haskell's limited IO capabilities. Basically, the tasks I would call 'practical' such as Aceept a request, find and process requested data, and return it formatted as needed seem to translate much more directly into procedural languages. The most luck I have had finding a functional language that works like this is Factor, which I would liken to a reverse-polish-notation version of Python. So I am just curious whether I have missed something in these languages or I am just way off the ball in how I ask this question. Does anyone have examples of functional languages that are great at performing practical tasks or practical tasks that are best performed by functional languages?

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  • ASP.NET CacheDependency out of ThreadPool

    - by Stephen
    In an async http handler, we add items to the ASP.NET cache, with dependencies on some files. If the async method executes on a thread from the ThreadPool, all is fine: AsyncResult result = new AsyncResult(context, cb, extraData); ThreadPool.QueueUserWorkItem(new WaitCallBack(DoProcessRequest), result); But as soon as we try to execute on a thread out of the ThreadPool: AsyncResult result = new AsyncResult(context, cb, extraData); Runner runner = new Runner(result); Thread thread = new Thread(new ThreadStart(runner.Run()); ... where Runner.Run just invokes DoProcessRequest, The dependencies do trigger right after the thread exits. I.e. the items are immediately removed from the cache, the reason being the dependencies. We want to use an out-of-pool thread because the processing might take a long time. So obviously something's missing when we create the thread. We might need to propagate the call context, the http context... Has anybody already encountered that issue? Note: off-the-shelf custom threadpools probably solve this. Writing our own threadpool is probably a bad idea (think NIH syndrom). Yet I'd like to understand this in details, though.

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