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  • Rails & ActiveRecord: Appending methods to models that inherit from ActiveRecord::Base

    - by PlankTon
    I have a standard ActiveRecord model with the following: class MyModel < ActiveRecord::Base custom_method :first_field, :second_field end At the moment, that custom_method is picked up by a module sent to ActiveRecord::Base. The functionality basically works, but of course, it attaches itself to every model class, not just MyModel. So if I have MyModel and MyOtherModel in the same action, it'll assume MyOtherModel has custom_method :first_field, :second_field as well. So, my question is: How do I attach a method (eg: def custom_method(*args)) to every class that inherits from ActiveRecord::Base, but not by attaching it to ActiveRecord::Base itself? Any ideas appreciated.

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  • Anonymous Methods / Lambda's (Coding Standards)

    - by Mystagogue
    In Jeffrey Richter's "CLR via C#" (the .net 2.0 edtion page, 353) he says that as a self-discipline, he never makes anonymous functions longer than 3 lines of code in length. He cites mostly readability / understandability as his reasons. This suites me fine, because I already had a self-discipline of using no more than 5 lines for an anonymous method. But how does that "coding standard" advice stack against lambda's? At face value, I'd treat them the same - keeping a lambda equally as short. But how do others feel about this? In particular, when lambda's are being used where (arguably) they shine brightest - when used in LINQ statements - is there genuine cause to abandon that self-discipline / coding standard?

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  • Boost Python : How to only expose the constructor of a class with virtual (pure & impure) methods

    - by fallino
    Hello, I'm a newbie with Boost::Python but I tried to search on the web to do so I want to expose a 3rd party library to Python. One of the class of the library (.hpp) is composed of a public constructor with arguments a protected constructor and functions various regular functions various pure virtual functions various non pure virtual functions First, I did not succeed in building it without having errors about this protected constructor. I finally commented it. A first question would be : Is there a way to exclude these protected functions since I don't want to expose them ? (I know it's possible and easy with Py++, but I started without using it) Then I tried to expose all of my functions, beginning with the pure virtual ones (commenting them all except one), which wasn't a success too So I finally decided not to expose these virtual functions (which in fact seems logical...), but, here again, I didn't manage building it with a simple constructor with arguments (without no_init). So my second question is : Is there a way to exclude these virtual functions since I don't want to expose them ? Sorry if it seems trivial but I didn't find anything explicit on the web and I need something rather explicit :). Thanks in advance

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  • Using Linq methods causes missing references to DependencyObject in WindowsBase

    - by Jason Coyne
    I have some c# source that I want to compile using CodeDom within my application (for a plugin) Everything works fine, except if I use a Linq extension function on some of my collections var dict = new Dictionary<KeyType, ValueType>(); .... dict.Any(KV=>KV.Key == "Some Key); When I try to compile source that has this code, it CodeDom complains that I am missing a reference to DependencyObject in WindowsBase. I do not understand why this is happening. Neither the Dictionary class, or the Any extension method reference that class, which apparently is part of Windows.Forms I would normally just ignore the quirk, make the CodeDom add a reference and move on, but Apparently WindowsBase is special and is not always distributed and I don't want to cause issues for users that may not have it installed correctly.

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  • Reference methods defined in one JScript file from another JScript

    - by Thomas Svensen
    I am writing some server-side scripts using jscript and WSH. The scripts are getting quite long, and some common functions and variables would fit better in a general library script which I included in my various script instances. But, I cannot find a way reference one JScript file from another. For a moment, I though reading the file contents and passing it to "eval()" could work. But, as it says on MSDN: "Note that new variables or types defined in the eval statement are not visible to the enclosing program." (http://msdn.microsoft.com/en-us/library/b51a45x6.aspx) Is there any way to include/refence a JScript from another one?

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  • How to keep my functions (objects/methods) 'lean and mean'

    - by Michel
    Hi, in all (Agile) articles i read about this: keep your code and functions small and easy to test. How should i do this with the 'controller' or 'coordinator' class? In my situation, i have to import data. In the end i have one object who coordinates this, and i was wondering if there is a way of keeping the coordinator lean(er) and mean(er). My coordinator now does the followling (pseudocode) //Write to the log that the import has started Log.StartImport() //Get the data in Excel sheet format result = new Downloader().GetExcelFile() //Log this step Log.LogStep(result ) //convert the data to intern objects result = new Converter().Convertdata(result); //Log this step Log.LogStep(result ) //write the data result = Repository.SaveData(result); //Log this step Log.LogStep(result ) Imho, this is one of those 'know all' classes or at least one being 'not lean and mean'? Or, am i taking this lean and mean thing to far and is it impossible to program an import without some kind of 'fat' importer/coordinator? Michel

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  • Implementing PyMyType_Check methods with Python C API?

    - by Paul D.
    All the Python-provided types have a check method (i.e., PyList_Check) that allows you to check if an arbitrary PyObject* is actually a specific type. How can I implement this for my own types? I haven't found anything good online for this, though it seems like a pretty normal thing to want to do. Also, maybe I'm just terrible at looking through large source trees, but I cannot for the life of me find the implementation of PyList_Check or any of it's companions in the Python (2.5) source.

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  • Test Driven Development For Complex Methods involving external dependency

    - by bill_tx
    I am implementing a Service Contract for WCF Service. As per TDD I wrote a test case to just pass it using hardcoded values. After that I started to put real logic into my Service implementation. The actual logic relies on 3-4 external service and database. What should I do to my original test case that I wrote ? If i Keep it same in order to make test pass it will have to call several other external services. So I have question in general what should I do if I write a test case for a Business Facade first using TDD and later when I add real logic, if it involves external dependency.

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  • Unable to call RESTful web services methods

    - by Alessandro
    Hello, I'm trying to dive into the RESTful web services world and have started with the following template: [ServiceContract] [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)] [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall)] public class Test { // TODO: Implement the collection resource that will contain the SampleItem instances [WebGet(UriTemplate = ""), OperationContract] public List<SampleItem> GetCollection() { // TODO: Replace the current implementation to return a collection of SampleItem instances return new List<SampleItem>() {new SampleItem() {Id = 1, StringValue = "Hello"}}; } [WebInvoke(UriTemplate = "", Method = "POST"), OperationContract] public SampleItem Create(SampleItem instance) { // TODO: Add the new instance of SampleItem to the collection throw new NotImplementedException(); } [WebGet(UriTemplate = "{id}"), OperationContract] public SampleItem Get(string id) { // TODO: Return the instance of SampleItem with the given id throw new NotImplementedException(); } [WebInvoke(UriTemplate = "{id}", Method = "PUT"), OperationContract] public SampleItem Update(string id, SampleItem instance) { return new SampleItem { Id = 99, StringValue = "Done" }; } [WebInvoke(UriTemplate = "{id}", Method = "DELETE"), OperationContract] public void Delete(string id) { // TODO: Remove the instance of SampleItem with the given id from the collection throw new NotImplementedException(); } } I am able to perform the GET operation but I am unable to perform PUT, POST or DELETE requests. Can anyone explain me how to perform these operations and how to create the correct URLs? Best regards Alessandro

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  • Why the concept of "Covariance" and "Contravariance" are applicable while implementing the methods o

    - by Amy
    The use case is some what like this: public class SomeClass: IClonable { // Some Code //Implementing interface method Public object Clone() { //Some Clonning Code } } Now my question is "Why is it not possible to use "SomeClass(As it is derivd from objec)" as a return type of Clone() method if we consider the Funda's of Covariance and Contravariance. Can somebody explain me the reason behind this implemementaion of Microsoft ????

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  • UIViewController rotate methods

    - by Corey Floyd
    What object is responsible for dipatching the UIViewController rotation method calls, i.e: – shouldAutorotateToInterfaceOrientation: – willRotateToInterfaceOrientation:duration: – willAnimateFirstHalfOfRotationToInterfaceOrientation:duration: – willAnimateSecondHalfOfRotationFromInterfaceOrientation:duration: – didRotateFromInterfaceOrientation: I imagine it is UIApplication (but maybe the AppDelegate or UIWindow). The next question, is how does the object know which UIViewController to talk to? How does it know which UIViewController has its view as the subview of the window? Is there a message you can send or a property you can set (of some object) that sets the "Active" UIViewController for the app?

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  • Copy Field and Methods

    - by javaguy
    I am new to java. I was wondering if there is a tool to copy fields and method easily. E.g if I have private String foo; // with getter/setters I should be able to select foo and type bar car in a textbox and the tool should generate fields bar and car with their getter/setters.

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  • removeFirst and addLast methods of LinkedList Class are Unknown

    - by user318068
    I have a problem with my code in C# . if i click in compiler button , I get the following errors 'System.Collections.Generic.LinkedList<int?>' does not contain a definition for 'removeFirst' and no extension method 'removeFirst' accepting a first argument of type 'System.Collections.Generic.LinkedList<int?>' could be found (are you missing a using directive or an assembly reference?). and 'System.Collections.Generic.LinkedList<Hanoi_tower.Sol>' does not contain a definition for 'addLast' and no extension method 'addLast' accepting a first argument of type 'System.Collections.Generic.LinkedList<Hanoi_tower.Sol>' could be found (are you missing a using directive or an assembly reference?) This is my program using System.; using System.Collections.Generic; using System.Linq; using System.Text; namespace Hanoi_tower { public class Sol { public LinkedList<int?> tower1 = new LinkedList<int?>(); public LinkedList<int?> tower2 =new LinkedList<int?>(); public LinkedList<int?> tower3 =new LinkedList<int?>(); public int depth; public LinkedList<Sol> neighbors; public Sol(LinkedList<int?> tower1, LinkedList<int?> tower2, LinkedList<int?> tower3) { this.tower1 = tower1; this.tower2 = tower2; this.tower3 = tower3; neighbors = new LinkedList<Sol>(); } public virtual void getneighbors() { Sol temp = this.copy(); Sol neighbor1 = this.copy(); Sol neighbor2 = this.copy(); Sol neighbor3 = this.copy(); Sol neighbor4 = this.copy(); Sol neighbor5 = this.copy(); Sol neighbor6 = this.copy(); if (temp.tower1.Count != 0) { if (neighbor1.tower2.Count != 0) { if (neighbor1.tower1.First.Value < neighbor1.tower2.First.Value) { neighbor1.tower2.AddFirst(neighbor1.tower1.RemoveFirst); neighbors.AddLast(neighbor1); } } else { neighbor1.tower2.AddFirst(neighbor1.tower1.RemoveFirst()); neighbors.AddLast(neighbor1); } if (neighbor2.tower3.Count != 0) { if (neighbor2.tower1.First.Value < neighbor2.tower3.First.Value) { neighbor2.tower3.AddFirst(neighbor2.tower1.RemoveFirst()); neighbors.AddLast(neighbor2); } } else { neighbor2.tower3.AddFirst(neighbor2.tower1.RemoveFirst()); neighbors.AddLast(neighbor2); } } //------------- if (temp.tower2.Count != 0) { if (neighbor3.tower1.Count != 0) { if (neighbor3.tower2.First.Value < neighbor3.tower1.First.Value) { neighbor3.tower1.AddFirst(neighbor3.tower2.RemoveFirst()); neighbors.AddLast(neighbor3); } } else { neighbor3.tower1.AddFirst(neighbor3.tower2.RemoveFirst()); neighbors.AddLast(neighbor3); } if (neighbor4.tower3.Count != 0) { if (neighbor4.tower2.First.Value < neighbor4.tower3.First.Value) { neighbor4.tower3.AddFirst(neighbor4.tower2.RemoveFirst()); neighbors.AddLast(neighbor4); } } else { neighbor4.tower3.AddFirst(neighbor4.tower2.RemoveFirst()); neighbors.AddLast(neighbor4); } } //------------------------ if (temp.tower3.Count() != 0) { if (neighbor5.tower1.Count() != 0) { if(neighbor5.tower3.ElementAtOrDefault() < neighbor5.tower1.ElementAtOrDefault()) { neighbor5.tower1.AddFirst(neighbor5.tower3.RemoveFirst()); neighbors.AddLast(neighbor5); } } else { neighbor5.tower1.AddFirst(neighbor5.tower3.RemoveFirst()); neighbors.AddLast(neighbor5); } if (neighbor6.tower2.Count() != 0) { if(neighbor6.tower3.element() < neighbor6.tower2.element()) { neighbor6.tower2.addFirst(neighbor6.tower3.removeFirst()); neighbors.addLast(neighbor6); } } else { neighbor6.tower2.addFirst(neighbor6.tower3.removeFirst()); neighbors.addLast(neighbor6); } } } public override string ToString() { string str; str="tower1"+ tower1.ToString() + " tower2" + tower2.ToString() + " tower3" + tower3.ToString(); return str; } public Sol copy() { Sol So; LinkedList<int> l1= new LinkedList<int>(); LinkedList<int> l2=new LinkedList<int>(); LinkedList<int> l3 = new LinkedList<int>(); for(int i=0;i<=this.tower1.Count() -1;i++) { l1.AddLast(tower1.get(i)); } for(int i=0;i<=this.tower2.size()-1;i++) { l2.addLast(tower2.get(i)); } for(int i=0;i<=this.tower3.size()-1;i++) { l3.addLast(tower3.get(i)); } So = new Sol(l1, l2, l3); return So; } public bool Equals(Sol sol) { if (this.tower1.Equals(sol.tower1) & this.tower2.Equals(sol.tower2) & this.tower3.Equals(sol.tower3)) return true; return false; } public virtual bool containedin(Stack<Sol> vec) { bool found =false; for(int i=0;i<= vec.Count-1;i++) { if(vec.get(i).tower1.Equals(this.tower1) && vec.get(i).tower2.Equals(this.tower2) && vec.get(i).tower3.Equals(this.tower3)) { found=true; break; } } return found; } } }

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  • writing a web service with dynamically determined web methods

    - by quillbreaker
    Let's say I have a text file of basic mathematical functions. I want to make a web service that answers these mathematical functions. Say the first one is y=x*x. If I wanted to turn this into a web service, I could simply do this: [WebMethod] public int A(int x) { return x*x; } However, I've extracted the function from the list by hand and coded it into a function by hand. That's not what I want to do. I want the wsdl for the service to be generated at call time directly from the text file, and I want the web method calls to the service to go to a specific method that also parses the text file at run time. How much heavy lifting is this? I've found a sample on how to generate WSDLs dynamically at this link, but there's a lot more to do beyond that and I don't want to bark up this tree if there are parts of the project that arn't feasible. Does anyone have any links, guides, books, or positive experiences trying this kind of thing?

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  • differing methods of alloc / init / retaining an object in objective-c

    - by taber
    In several pieces of sample objective-c code I've seen people create new objects like this: RootViewController *viewController = [[RootViewController alloc] init]; self.rootViewController = viewController; // self.rootViewController is a (nonatomic,retain) synthesized property [viewController release]; [window addSubview: [self.rootViewController view]]; Is that any different "behind the scenes" than doing it like this instead? self.rootViewController = [[RootViewController alloc] init]; [window addSubview: [self.rootViewController view]]; Seems a bit more straightforward/streamlined that way so I'm wondering why anyone would opt for the first method. Thanks!

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  • Need help with Xpath methods in javascript (selectSingleNode, selectNodes)

    - by Andrija
    I want to optimize my javascript but I ran into a bit of trouble. I'm using XSLT transformation and the basic idea is to get a part of the XML and subquery it so the calls are faster and less expensive. This is a part of the XML: <suite> <table id="spis" runat="client"> <rows> <row id="spis_1"> <dispatch>'2008', '288627'</dispatch> <data col="urGod"> <title>2008</title> <description>Ur. god.</description> </data> <data col="rbr"> <title>288627</title> <description>Rbr.</description> </data> ... </rows> </table> </suite> In the page, this is the javascript that works with this: // this is my global variable for getting the elements so I just get the most // I can in one call elemCollection = iDom3.Table.all["spis"].XML.DOM.selectNodes("/suite/table/rows/row").context; //then I have the method that uses this by getting the subresults from elemCollection //rest of the method isn't interesting, only the selectNodes call _buildResults = function (){ var _RowList = elemCollection.selectNodes("/data[@col = 'urGod']/title"); var tmpResult = ['']; var substringResult=""; for (i=0; i<_RowList.length; i++) { tmpResult.push(_RowList[i].text,iDom3.Global.Delimiter); } ... //this variant works elemCollection = iDom3.Table.all["spis"].XML.DOM _buildResults = function (){ var _RowList = elemCollection.selectNodes("/suite/table/rows/row/data[@col = 'urGod']/title"); var tmpResult = ['']; var substringResult=""; for (i=0; i<_RowList.length; i++) { tmpResult.push(_RowList[i].text,iDom3.Global.Delimiter); } ... The problem is, I can't find a way to use the subresults to get what I need.

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  • Method binding to base method in external library can't handle new virtual methods "between"

    - by Berg
    Lets say I have a library, version 1.0.0, with the following contents: public class Class1 { public virtual void Test() { Console.WriteLine( "Library:Class1 - Test" ); Console.WriteLine( "" ); } } public class Class2 : Class1 { } and I reference this library in a console application with the following contents: class Program { static void Main( string[] args ) { var c3 = new Class3(); c3.Test(); Console.ReadKey(); } } public class Class3 : ClassLibrary1.Class2 { public override void Test() { Console.WriteLine("Console:Class3 - Test"); base.Test(); } } Running the program will output the following: Console:Class3 - Test Library:Class1 - Test If I build a new version of the library, version 2.0.0, looking like this: public class Class1 { public virtual void Test() { Console.WriteLine( "Library:Class1 - Test V2" ); Console.WriteLine( "" ); } } public class Class2 : Class1 { public override void Test() { Console.WriteLine("Library:Class2 - Test V2"); base.Test(); } } and copy this version to the bin folder containing my console program and run it, the results are: Console:Class3 - Test Library:Class1 - Test V2 I.e, the Class2.Test method is never executed, the base.Test call in Class3.Test seems to be bound to Class1.Test since Class2.Test didn't exist when the console program was compiled. This was very surprising to me and could be a big problem in situations where you deploy new versions of a library without recompiling applications. Does anyone else have experience with this? Are there any good solutions? This makes it tempting to add empty overrides that just calls base in case I need to add some code at that level in the future...

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  • SKProductsRequest delegate methods are never called.

    - by coneybeare
    This used to work for me but is now not working anymore and I can't figure out why. I have in-app purchase setup in my app. I confirmed that I have a correct set of product identifiers, matched by corresponding in-app purchase items in itunesconnect. The call goes out to Apple view [productRequest start], but I never get a response back, despite setting the delegate to myself. What am I missing? NSLog(@"productIdentifiersSet: %@", productIdentifiersSet); if ([productIdentifiersSet count]) { SKProductsRequest *productRequest = [[SKProductsRequest alloc] initWithProductIdentifiers:productIdentifiersSet]; [productRequest setDelegate:self]; [productRequest start]; } ……… - (void)productsRequest:(SKProductsRequest *)request didReceiveResponse:(SKProductsResponse *)response { <never called> } - (void)requestDidFinish:(SKRequest *)request { <never called> } - (void)request:(SKRequest *)request didFailWithError:(NSError *)error { <never called> }

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  • How to avoid code duplication for one-off methods with a slightly different signature

    - by Sean
    I am wrapping a number of functions from a vender API in C#. Each of the wrapping functions will fit the pattern: public IEnumerator<IValues> GetAggregateValues(string pointID, DateTime startDate, DateTime endDate, TimeSpan period) { // Validate Data // Break up Requesting Time-Span // Make Requests // Read Results (through another method call } 5 of the 6 requests are aggregate data pulls and have the same signature, so it makes sense to put them in one method and pass the aggregate type to avoid duplication of code. The 6th method however follows the exact same pattern with the same result-set, but is not an aggregate, so no time period is passed to the function (changing the signature). Is there an elegant way to handle this kind of situation without coding a one-off function to handle the non-aggregate request?

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  • Compiler error when overwriting virtual methods

    - by Stefan Hubert
    Using VC71 compiler and get compiler errors, that i don't understand. Here comes the example class A { public: virtual int& myMethod() = 0; virtual const int& myMethod()const = 0; }; class B: public A { public: // generates: error C3241: 'const int &B::myMethod(void)' : this method was not introduced by 'A' virtual const int& A::myMethod() const; virtual int& A::myMethod(); }; when i switch order of both method definitions in B then I see a different compiler error: class B: public A { public: virtual const int& A::myMethod() const; // error C2556: 'const int &B::myMethod(void)' : overloaded function differs only by return type from 'int &B::myMethod(void)' // error C2373: 'B::myMethod' : redefinition; different type modifiers virtual int& A::myMethod(); }; however, if I omit the A:: stuff then i don't get any compiler error: class B: public A { public: virtual int& myMethod(); virtual const int& myMethod() const; }; So, what exactly does A:: in front of my method names and why do i see these diverse compiler errors? Any explanation welcome!

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  • good __eq__, __lt__, ..., __hash__ methods for image class?

    - by Marten Bauer
    I create the following class: class Image(object): def __init__(self, extension, data, urls=None, user_data=None): self._extension = extension self._data = data self._urls = urls self._user_data = user_data self._hex_digest = hashlib.sha1(self._data).hexDigest() Images should be equal when all values are equal. Therefore I wrote: def __eq__(self, other): if isinstance(other, Image) and self.__dict__ == other.__dict__: return True return False def __ne__(self, other): return not self.__eq__(other) def __lt__(self, other): return self.__dict__ < other.__dict__ ... But how should the __hash__ method look like? Equal Images should return equal hashes... def __hash__(self): # won't work !?! return hash(self.__dict__) Is the way I try to use __eq__, __ne__, __lt__, __hash__, ... recommend?

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