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• How do i translate this to "simpler" JavaScript?

  - by Julian Weimer

  Since i'm working with Titanium i realzed that its current JavaScript Interpreter doesn't accept specific coding-styles. So for for-loops and if-statements i have to have braces, even though i only want to span one line. Furthermore there is more i have to change if i want to use a Javascript Library like underscore.js. This is what Titanium doesn't want to see: if (!(result = result && iterator.call(context, value, index, list))) {_.breakLoop();} if (nativeSome && obj.some === nativeSome) {return obj.some(iterator, context);} var computed = iterator ? iterator.call(context, value, index, list) : value; computed >= result.computed && (result = {value : value, computed : computed}); Can i use a simpler syntax to describe the logic behind those lines of code?

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• Right design to validate attributes of a class instance

  - by systempuntoout

  Having a simple Python class like this: class Spam(object): __init__(self, description, value): self.description = description self.value = value Which is the correct approach to check these constraints: "description cannot be empty" "value must be greater than zero" Should i: 1.validate data before creating spam object ? 2.check data on __init__ method ? 3.create an is_valid method on Spam class and call it with spam.isValid() ? 4.create an is_valid static method on Spam class and call it with Spam.isValid(description, value) ? 5.check data on setters? 6.... Could you recommend a well designed\Pythonic\not verbose (on class with many attributes)\elegant approach?

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• Printing complex widgets in Qt

  - by Jens

  I have a complex widget with tons of different subwidgets, e.g. subclasses of QLabel. I want to print this widget, but obviously I do not want to print the background, I want to print with differing text colors or have the style of frames slightly modified. As I do not really want to iterate through all subwidgets with a special "print" function, which I would need to attach to all widgets (how to add "print" to a QLabel?), I would like to use paintEvent. If I have a hierarchy MyWidget - derived from - some QWidget, I would like to insert a sublayer MyWidget - MyPrintWidget - some QWidget, where myPrintWidget::paintEvent would check, if the current print is going to the screen (thus call QWidget::paintEvent), else if we are printing to the printer, call some function MyPrintWidget::drawWidget instead. Is this the right way to print-enable a widget? How can I figure out in paintEvent, that I'm printing to a printer instead of the screen? Is there a good example of printing complex widgets?

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• Where are the function literals c++?

  - by academicRobot

  First of all, maybe literals is not the right term for this concept, but its the closest I could think of (not literals in the sense of functions as first class citizens). The idea is that when you make a conventional function call, it compiles to something like this: callq <immediate address> But if you make a function call using a function pointer, it compiles to something like this: mov <memory location>,%rax callq *%rax Which is all well and good. However, what if I'm writing a template library that requires a callback of some sort with a specified argument list and the user of the library is expected to know what function they want to call at compile time? Then I would like to write my template to accept a function literal as a template parameter. So, similar to template <int int_literal> struct my_template {...};` I'd like to write template <func_literal_t func_literal> struct my_template {...}; and have calls to func_literal within my_template compile to callq <immediate address>. Is there a facility in C++ for this, or a work around to achieve the same effect? If not, why not (e.g. some cataclysmic side effects)? How about C++0x or another language? Solutions that are not portable are fine. Solutions that include the use of member function pointers would be ideal. I'm not particularly interested in being told "You are a <socially unacceptable term for a person of low IQ>, just use function pointers/functors." This is a curiosity based question, and it seems that it might be useful in some (albeit limited) applications. It seems like this should be possible since function names are just placeholders for a (relative) memory address, so why not allow more liberal use (e.g. aliasing) of this placeholder. p.s. I use function pointers and functions objects all the the time and they are great. But this post got me thinking about the don't pay for what you don't use principle in relation to function calls, and it seems like forcing the use of function pointers or similar facility when the function is known at compile time is a violation of this principle, though a small one.

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• Problem overridding virtual function

  - by William

  Okay, I'm writing a game that has a vector of a pairent class (enemy) that s going to be filled with children classes (goomba, koopa, boss1) and I need to make it so when I call update it calls the childclasses respective update. I have managed to create a example of my problem. #include <stdio.h> class A{ public: virtual void print(){printf("Hello from A");} }; class B : public A{ public: void print(){printf("Hello from B");} }; int main(){ A ab = B(); ab.print(); while(true){} } Output wanted: "Hello from B" Output got: "Hello from A" How do I get it to call B's print function?

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• Cache an FTP connection via session variables for use via AJAX?

  - by Chad Johnson

  I'm working on a Ruby web Application that uses the Net::FTP library. One part of it allows users to interact with an FTP site via AJAX. When the user does something, and AJAX call is made, and then Ruby reconnects to the FTP server, performs an action, and outputs information. Every time the AJAX call is made, Ruby has to reconnect to the FTP server, and that's slow. Is there a way I could cache this FTP connection? I've tried caching in the session hash, but "We're sorry, but something went wrong" is displayed, and a TCP dump is outputted in my logs whenever I attempt to store it in the session hash. I haven't tried memcache yet. Any suggestions?

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• Is concatenating with an empty string to do a string conversion really that bad?

  - by polygenelubricants

  Let's say I have two char variables, and later on I want to concatenate them into a string. This is how I would do it: char c1, c2; // ... String s = "" + c1 + c2; I've seen people who say that the "" + "trick" is "ugly", etc, and that you should use String.valueOf or Character.toString instead. I prefer this construct because: I prefer using language feature instead of API call if possible In general, isn't the language usually more stable than the API? If language feature only hides API call, then even stronger reason to prefer it! More abstract! Hiding is good! I like that the c1 and c2 are visually on the same level String.valueOf(c1) + c2 suggests something is special about c1 It's shorter. Is there really a good argument why String.valueOf or Character.toString is preferrable to "" +? Trivia: in java.lang.AssertionError, the following line appears 7 times, each with a different type: this("" + detailMessage);

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• make a lazy var in scala

  - by ayvango

  Scala does not permit to create laze vars, only lazy vals. It make sense. But I've bumped on use case, where I'd like to have similar capability. I need a lazy variable holder. It may be assigned a value that should be calculated by time-consuming algorithm. But it may be later reassigned to another value and I'd like not to call first value calculation at all. Example assuming there is some magic var definition lazy var value : Int = _ val calc1 : () => Int = ... // some calculation val calc2 : () => Int = ... // other calculation value = calc1 value = calc2 val result : Int = value + 1 This piece of code should only call calc2(), not calc1 I have an idea how I can write this container with implicit conversions and and special container class. I'm curios if is there any embedded scala feature that doesn't require me write unnecessary code

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• Why in Objective-C, we use self = [super init] instead of just [super init]?

  - by ????

  In a book, I saw that if a subclass is overriding a superclass's method, we may have self = [super init]; First, is this supposed to be done in the subclass's init method? Second, I wonder why the call is not just [super init]; ? I mean, at the time of calling init, the memory is allocated by alloc already (I think by [Foobar alloc] where Foobar is the subclass's name. So can't we just call [super init] to initialize the member variables? Why do we have to get the return value of init and assign to self? I mean, before calling [super init], self should be pointing to a valid memory allocation chuck... so why assigning something to self again? (if assigning, won't [super init] just return self's existing value?)

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• how to use proxy with JSON

  - by Dele

  I have a php page called 'dataFetch.php' which sits on one webserver. On another webserver, I have a JS file which issues JSON calls to dataFetch. dataFetch connects to a database, retrieves data and puts it in a JSON format which is fed back to the calling program. In IE, this works fine. In other browsers it does not because of the cross domain restriction. To get across the cross-domain restriction, I make a call to a file, proxy.php, which then makes the call to dataFetch. My problem now is that proxy.php retrieves the file from dataFetch but the JS script file no longer sees the response from proxy.php as a JSON format and so I can't process it. Can anybody help me out?

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• iphone singleton object synchronization

  - by user127091

  I'm working on an iphone app but this is probably a general question. I have a singleton Model class and there would be scenarios where multiple NSOperations (threads) would exist and work with the singleton object. If they all call the same method in this object, do i need to have some locking mechanism? Or can this method be executed only one at a time? I do not have a computer science background but my guess is that all threads would have their CALL to the same address (this method). Also can you please suggest a good beginner programming book that discusses general programming concepts. I don't have the brains for Knuth kinda books.

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• Controlling the visibility of a Bitmap in .NET

  - by ET

  Hi everyone, I am trying to create this simple application in c#: when the user double clicks on specific location in the form, a little circle will be drawn. By one click, if the current location is marked by a circle - the circle will be removed. I am trying to do this by simply register the MouseDoubleClick and MouseClick events, and to draw the circle from a .bmp file the following way: private void MouseDoubleClick (object sender, MouseEventArgs e) { Graphics g = this.CreateGraphics(); Bitmap myImage = (Bitmap)Bitmap.FromFile("Circle.bmp"); g.DrawImage(myImage, e.X, e.Y); } My problem is that I dont know how to make the circle unvisible when the user clicks its location: I know how to check if the selected location contains a circle (by managing a list of all the locations containig circles...), but I dont know how exactly to delete it. Another question: should I call the method this.CreateGraphics() everytime the user double-clicks a location, as I wrote in my code snippet, or should I call it once on initialization?

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• silverlight and windows workflow foundation

  - by wissem

  private void btnUpdate_Click(object sender, RoutedEventArgs e) { xxxxxxx.Workflow1_WebServiceSoapClient zer = new xxxxx.Workflow1_WebServiceSoapClient(); zer.demanderSubmitReportCompleted += new EventHandler<xxxxxxxxxxxxxxx.demanderSubmitReportCompletedEventArgs>(service2); zer.demanderSubmitReportAsync("zzz", 20000); } public void service2(object sender, xxxxx.demanderSubmitReportCompletedEventArgs e) { string a = e.Result; } I'm trying to call a windows workflow foundation published as a web service from a Silverlight project. When I call it from a console application it works fine because I can add a web reference then I just make an instance of that webservice then I invoke the method I want. The problem is in the silverlight project cause i can just add a service reference so I find myself working with soap stuff that doesn't work at all, and here is the code error: here is the code:i change it a litle bit in english Error in exécution Microsoft JScript: Unhandled Error in Silverlight Application exception happened in the operation, résult not valide. Consult InnerException for more information. in System.ComponentModel.AsyncCompletedEventArgs.RaiseExceptionIfNecessary() in AEDSilverlightIntegrated.ServiceReference2.demanderSubmitReportCompletedEventArgs.get_Result() in AEDSilverlightIntegrated.SilverEntryAedHeaderNew.mmm_demanderSubmitReportCompleted(Object sender, demanderSubmitReportCompletedEventArgs e) in AEDSilverlightIntegrated.ServiceReference2.Workflow1_WebServiceSoapClient.OndemanderSubmitReportCompleted(Object state)

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• How to abandon a hg merge?

  - by Grumdrig

  I'm new to collaborating with Mercurial. My situation: Another programmer changed rev 1 of a file to replace 4-space indents with 2-space indent. (I.e. changed every line.) Call that rev 2, pushed to the remote repo. I've committed substantive changes rev 1 with various code changes in my local workspace. Call that rev 3. I've hg pulled and hg merged without a clear idea of what was going on. The conflicts are myriad and not really substantive. So I really wish I'd changed my local repo to 2-space indents before merging; then the merge will be trivial (i'm supposing). But I can't seem to back up. I think I need to hg update -r 3 but it says abort: outstanding uncommitted merges. How can I undo the merge, changes spacing in my local repo, and remerge?

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• How do I set a value to the Session in asp.net on an onClick event of a normal htmlElement?

  - by William Calleja

  I need to make a Function that receives a Session Key and a Session Value and call this function on a normal HTML onClick event. When this function is called the Session variable is assigned the Key I sent with the Value I sent. So far I have this: <script runat="server" type="text/C#"> protected void setSessionValue(string key, string value) { Session[key] = value; } </script> But when I try to call if like so: onclick="setSessionValue('itemID','3345');" Its not working and giving me an error. Any help? I'm using c# and asp.net but I can't use code behind and need to work everything off the page.

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• class method as hash value

  - by demas

  I have this working code: class Server def handle(&block) @block = block end def do @block.call end end class Client def initialize @server = Server.new @server.handle { action } end def action puts "some" end def call_server @server.do end end client = Client.new client.call_server My Server will handle more then one action so I want to change code such way: class Server def handle(options) @block = options[:on_filter] end def do @block.call end end class Client def initialize @server = Server.new my_hash = { :on_filter => action } @server.handle(my_hash) end def action puts "some" end def call_server @server.do end end client = Client.new client.call_server It is incorrect code because action() method calls on create my_hash, but if I try to modify code to: my_hash = { :on_filter => { action } } i get error message. Is it possible to create hash with methods as hash values ?

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• How to create an MSI package that installs no files and only executes some commands using Wix

  - by Sevas

  I am trying to create an MSI package that uses the AppCmd application to configure IIS7. It only has to execute some commands that call AppCmd. Some commands need to be called when installing, other commands need to be called when uninstalling. Here is what I have now: I have a property that points to AppCmd: <Property Id="APPCMD" Value="C:\Windows\system32\inetsrv\appcmd.exe" /> I have my custom actions: <CustomAction Id="UnlockHandlerSection" Return="check" Property="APPCMD" ExeCommand="unlock config /section:system.webServer/handlers" /> I have Custom elements that call the actions: <InstallExecuteSequence> <Custom Action="UnlockHandlerSection" After="InstallFiles">NOT Installed AND NOT PATCH</Custom> <InstallExecuteSequence> The problem with this is is that the commands are not called when I try to install the resulting MSI package. Could anyone please advise me on what I am doing wrong? Thank you!

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• catching the value of a time_select in rails.

  - by ZeroSoul13

  Hello, I have a form that has two field (time_selects), the idea is that the user can select the beginning of a call and end time of the call. I've setup a observe field and works fine: <%= observe_field "llamada_inicio_4i", :update => "total", :with => "llamada_inicio_4i", :url => { :controller => "llamadas", :action => "time_tracker"}%> Sends the value out: Processing LlamadasController#time_tracker (for 127.0.0.1 at 2010-04-22 17:48:41) [POST] Parameters:"llamada_inicio_4i"="23",authenticity_token"="+D+yPSVue6yQNfPMuVLkrJn7B9tP6z5S1icKpPFTiso="} Rendering template within layouts/llamadas Rendering llamadas/time_tracker Completed in 5ms (View: 3, DB: 0) | 200 OK [http://0.0.0.0/llamadas /time_tracker] How can i catch this value Parameters:"llamada_inicio_4i"="23"

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• C++: Overload != When == Overloaded

  - by Mark W

  Say I have a class where I overloaded the operator == as such: Class A { ... public: bool operator== (const A &rhs) const; ... }; ... bool A::operator== (const A &rhs) const { .. return isEqual; } I already have the operator == return the proper Boolean value. Now I want to extend this to the simple opposite (!=). I would like to call the overloaded == operator and return the opposite, i.e. something of the nature bool A::operator!= (const A &rhs) const { return !( this == A ); } Is this possible? I know this will not work, but it exemplifies what I would like to have. I would like to keep only one parameter for the call: rhs. Any help would be appreciated, because I could not come up with an answer after several search attempts.

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• C++ setTimout function ?

  - by Quandary

  What's the cheapest way for a JavaScript like setTimeout-function in C++? I would need this: 5000 miliseconds from now, start function xy (no parameters, no return value). The reason for this is I need to initialize COM for text to speech, but when I do it on dll attach, it crashes. It works fine however if I do not call CoInitialize from dllmain. I just need to call CoInitialize and CoCreateInstance, and then use the instance in other functions. I can catch the uninitialized instance by checking for NULL, but I need to initialize COM - without crashing.

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• Silverlight calling windows workflow foundation as a web service

  - by wissem

  hi, I'm trying to call a windows workflow foundation published as a web service from a Silverlight project. When I call it from a console application it works fine because I can add a web reference then I just make an instance of that webservice then I invoke the method I want. The problem is in the silverlight project cause i can just add a service reference so I find myself working with soap stuff that doesn't work at all, and here is the code: private void btnUpdate_Click(object sender, RoutedEventArgs e) { xxxxxxx.Workflow1_WebServiceSoapClient zer = new xxxxx.Workflow1_WebServiceSoapClient(); zer.demanderSubmitReportCompleted += new EventHandler<xxxxxxxxxxxxxxx.demanderSubmitReportCompletedEventArgs>(service2); zer.demanderSubmitReportAsync("zzz", 20000); } public void service2(object sender, xxxxx.demanderSubmitReportCompletedEventArgs e) { string a = e.Result; } plz help ,thanks

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• Function calls in virtual machine killing performance

  - by GenTiradentes

  I wrote a virtual machine in C, which has a call table populated by pointers to functions that provide the functionality of the VM's opcodes. When the virtual machine is run, it first interprets a program, creating an array of indexes corresponding to the appropriate function in the call table for the opcode provided. It then loops through the array, calling each function until it reaches the end. Each instruction is extremely small, typically one line. Perfect for inlining. The problem is that the compiler doesn't know when any of the virtual machine's instructions are going to be called, as it's decided at runtime, so it can't inline them. The overhead of function calls and argument passing is killing the performance of my VM. Any ideas on how to get around this?

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• Can I access an iframe of the same domain in a separate window?

  - by jozecuervo

  How can I detect the presence of and then call a function on a frame that is already loaded in one tab (my iframed facebook app) from a page being loaded in a new tab (from an ad-served link). It seems most examples focus on parent/child iframe communication. In this case, a link will be served from Google Ad Manager, which only allows _top or _blank to be targeted. I want to pass an id through the ad click into the new page/tab on my domain and then JS call over to the frame my app is in to switch state. Both frames are on my domain but not in the same document or window. Is this possible?

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• Use of function pointers for callling functions in a DLL

  - by viswanathan

  Is it possible to call a function in a DLL loaded dynamically without making use of function pointers.

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• Which type of Rails model association should I use in this situation?

  - by jstayton

  I have two models/tables in my Rails application: discussions and comments. Each discussion has_many comments, and each comment belongs_to a discussion. My discussions table also includes a first_comment_id column and last_comment_id column for convenience and speed. I want to be able to call discussion.last_comment for the last comment model, but the following (in my discussion model) isn't working to make this happen: has_one :first_comment, :class_name => "Comment" has_one :last_comment, :class_name => "Comment" When I call discussion.last_comment, the following SQL is run: SELECT * FROM `comments` WHERE (`comments`.discussion_id = 1) LIMIT 1 It's using the discussions.id column to join against comments.discussion_id, when I want it to join discussions.last_comment_id against comments.id. Am I using the wrong type of association here? Thanks for your help!

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