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  • Static Vs Non-Static Method Performance C#

    - by dotnetguts
    Hello All, I have few global methods declared in public class in my asp.net web application. I have habbit of declaring all global methods in public class in following format public static string MethodName(parameters) { } I want to know how it would impact on performance point of view? 1) Which one is Better? Static Method or Non-Static Method? 2) Reason why it is better? Following link shows Non-Static methods are good because, static methods are using locks to be Thread-safe. The always do internally a Monitor.Enter() and Monitor.exit() to ensure Thread-safety. http://bytes.com/topic/c-sharp/answers/231701-static-vs-non-static-function-performance And Following link shows Static Methods are good static methods are normally faster to invoke on the call stack than instance methods. There are several reasons for this in the C# programming language. Instance methods actually use the 'this' instance pointer as the first parameter, so an instance method will always have that overhead. Instance methods are also implemented with the callvirt instruction in the intermediate language, which imposes a slight overhead. Please note that changing your methods to static methods is unlikely to help much on ambitious performance goals, but it can help a tiny bit and possibly lead to further reductions. http://dotnetperls.com/static-method I am little confuse which one to use? Thanks

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  • iOS: click counter for row in tableview

    - by roger.arliner21
    I am developing and tableView in which in each row I have to display the click counter and row number.Each cell must have an initial click counter value of 0 when application is initialized. Then increment the click counter value within a cell whenever a user clicks on the cell. I have take 26 fixed rows. I have taken tableData.plist file as in the attached image. I am initializing the self.dataArray with the plist . Now I want to do implementation in the didSelectRowAtIndexPath delegate method,if any row is tapped that row's click counter should increment. - (void)viewDidLoad { [super viewDidLoad]; NSString *path = [[NSBundle mainBundle] pathForResource:@"tableData" ofType:@"plist"]; self.dataArray = [NSMutableArray arrayWithContentsOfFile:path];//array initialized with plist } - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return [self.dataArray count]; } - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *kCustomCellID = @"MyCellID"; UILabel *label1 = [[UILabel alloc] initWithFrame:CGRectMake(160.0f, 2.0f, 30.0f, 20.0f)]; UILabel *label2 = [[UILabel alloc] initWithFrame:CGRectMake(160.0f, 24.0f, 30.0f, 30.0f)]; label2.textColor = [UIColor grayColor]; UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:kCustomCellID]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:kCustomCellID] autorelease]; cell.selectionStyle = UITableViewCellSelectionStyleNone; } if([self.dataArray count]>indexPath.row) { label1.text = [[self.dataArray objectAtIndex:indexPath.row] objectForKey:@"Lable1"]; label2.text =[[self.dataArray objectAtIndex:indexPath.row] objectForKey:@"Lable2"]; } else { label1.text = @""; label2.text =@""; } [cell.contentView addSubview:label1]; [cell.contentView addSubview:label2]; [label1 release]; [label2 release]; return cell; } #pragma mark - #pragma mark Table view delegate - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { //implementation for row counter incrementer. }

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  • Implementing Dispose on a class derived from Stream

    - by AnthonyWJones
    I'm building a class that derives from Stream to wrap a COM IStream. However I've come across an issue where I need to release the COM IStream deteministically. Ok so that's easy just use Marshal.ReleaseComObject in the Dispose method. However I'm not sure its that simple. The Stream base class already has an protected virtual method Dispose(boolean). Here is my first idea:- ~ComStreamWrapper() { if (!_Disposed) { iop.Marshal.FreeCoTaskMem(_Int64Ptr); iop.Marshal.ReleaseComObject(_IStream); } } protected override void Dispose(bool disposing) { base.Dispose(disposing); if (!_Disposed) { if (disposing) { iop.Marshal.FreeCoTaskMem(_Int64Ptr); iop.Marshal.ReleaseComObject(_IStream); } _Disposed = true; } } You'll notice there isn't an implementation of Dispose() itself. I'm currently making the asssumption that the existing implementation on Stream does what I need it to. That is calling Diposing(true) and GC.SuppressFinalize. Is this assumption faulty? Have I missed something? Is there a better approach? You see more of the basic class in this answer to an ealier question.

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  • Why won't WPF databindings show text when ToString() has a collaborating object?

    - by Jay
    In a simple form, I bind to a number of different objects -- some go in listboxes; some in textblocks. A couple of these objects have collaborating objects upon which the ToString() method calls when doing its work -- typically a formatter of some kind. When I step through the code I see that when the databinding is being set up, ToString() is called the collaborating object is not null and returns the expected result when inspected in the debugger, the objects return the expected result from ToString() BUT the text does not show up in the form. The only common thread I see is that these use a collaborating object, whereas the other bindings that show up as expected simply work from properties and methods of the containing object. If this is confusing, here is the gist in code: public class ThisThingWorks { private SomeObject some_object; public ThisThingWorks(SomeObject s) { some_object = s; } public override string ToString() { return some_object.name; } } public class ThisDoesntWork { private Formatter formatter; private SomeObject some_object; public ThisDoesntWork(SomeObject o, Formatter f) { formatter = f; some_object = o; } public override string ToString() { return formatter.Format(some_object.name); } } Again, let me reiterate -- the ToString() method works in every other context -- but when I bind to the object in WPF and expect it to display the result of ToString(), I get nothing. Update: The issue seems to be what I see as a buggy behaviour in the TextBlock binding. If I bind the Text property to a property of the DataContext that is declared as an interface type, ToString() is never called. If I change the property declaration to an implementation of the interface, it works as expected. Other controls, like Label work fine when binding the Content property to a DataContext property declared as either the implementation or the interface. Because this is so far removed from the title and content of this question, I've created a new question here: http://stackoverflow.com/questions/2917878/why-doesnt-textblock-databinding-call-tostring-on-a-property-whose-compile-tim

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  • Parameterized SPARQL query with JENA

    - by sandra
    I'm trying to build a small semantic web application using Jena framework, JSP and JAVA. I have a remote SPARQL endpoint and I've already written a simple query which works fine but now I need to use some parameters. Here is my code so far: final static String serviceEndpoint = "http://fishdelish.cs.man.ac.uk/sparql/"; String comNameQuery = "PREFIX fd: <http://fishdelish.cs.man.ac.uk/rdf/vocab/resource/> " + "SELECT ?name ?language ?type" + "WHERE { ?nameID fd:comnames_ComName ?name ;" + "fd:comnames_Language ?language ;" + "fd:comnames_NameType ?type ." + "}"; Query query = QueryFactory.create(comNameQuery); QueryExecution qe = QueryExecutionFactory.sparqlService(serviceEndpoint,query); try { ResultSet rs = qe.execSelect(); if ( rs.hasNext() ) { System.out.println(ResultSetFormatter.asText(rs)); } } catch(Exception e) { System.out.println(e.getMessage()); } finally { qe.close(); } What I want to do is to parameterized ?name. I'm new to Jena and I'm not really sure how to use parameters in a SPARQL query. I would appreciate it if someone could help me with this.

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  • Algorithm for generating an array of non-equal costs for a transport problem optimization

    - by Carlos
    I have an optimizer that solves a transportation problem, using a cost matrix of all the possible paths. The optimiser works fine, but if two of the costs are equal, the solution contains one more path that the minimum number of paths. (Think of it as load balancing routers; if two routes are same cost, you'll use them both.) I would like the minimum number of routes, and to do that I need a cost matrix that doesn't have two costs that are equal within a certain tolerance. At the moment, I'm passing the cost matrix through a baking function which tests every entry for equality to each of the other entries, and moves it a fixed percentage if it matches. However, this approach seems to require N^2 comparisons, and if the starting values are all the same, the last cost will be r^N bigger. (r is the arbitrary fixed percentage). Also there is the problem that by multiplying by the percentage, you end up on top of another value. So the problem seems to have an element of recursion, or at least repeated checking, which bloats the code. The current implementation is basically not very good (I won't paste my GOTO-using code here for you all to mock), and I'd like to improve it. Is there a name for what I'm after, and is there a standard implementation? Example: {1,1,2,3,4,5} (tol = 0.05) becomes {1,1.05,2,3,4,5}

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  • Diff/Merge functionality for objects (not files!)

    - by gehho
    I have a collection of objects of the same type, let's call it DataItem. The user can view and edit these items in an editor. It should also be possible to compare and merge different items, i.e. some sort of diff/merge for DataItem instances. The DIFF functionality should compare all (relevant) properties/fields of the items and detect possible differences. The MERGE functionality should then be able to merge two instances by applying selected differences to one of the items. For example (pseudo objects): DataItem1 { DataItem2 { Prop1 = 10 Prop1 = 10 Prop2 = 25 Prop2 = 13 Prop3 = 0 Prop3 = 5 Coll = { 7, 4, 8 } Coll = { 7, 4, 8, 12 } } } Now, the user should be provided with a list of differences (i.e. Prop2, Prop3, and Coll) and he should be able to select which differences he wants to eliminate by assigning the value from one item to the other. He should also be able to choose if he wants to assign the value from DataItem1 to DataItem2 or vice versa. Are there common practices which should be used to implement this functionality? Since the same editor should also provide undo/redo functionality (using the Command pattern), I was thinking about reusing the ICommand implementations because both scenarios basically handle with property assignments, collection changes, and so on... My idea was to create Difference objects with ICommand properties which can be used to perform a merge operation for this specific Difference. Btw: The programming language will be C# with .NET 3.5SP1/4.0. However, I think this is more of a language-independent question. Any design pattern/idea/whatsoever is welcome!

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  • What's a good way to provide additional decoration/metadata for Python function parameters?

    - by Will Dean
    We're considering using Python (IronPython, but I don't think that's relevant) to provide a sort of 'macro' support for another application, which controls a piece of equipment. We'd like to write fairly simple functions in Python, which take a few arguments - these would be things like times and temperatures and positions. Different functions would take different arguments, and the main application would contain user interface (something like a property grid) which allows the users to provide values for the Python function arguments. So, for example function1 might take a time and a temperature, and function2 might take a position and a couple of times. We'd like to be able to dynamically build the user interface from the Python code. Things which are easy to do are to find a list of functions in a module, and (using inspect.getargspec) to get a list of arguments to each function. However, just a list of argument names is not really enough - ideally we'd like to be able to include some more information about each argument - for instance, it's 'type' (high-level type - time, temperature, etc, not language-level type), and perhaps a 'friendly name' or description. So, the question is, what are good 'pythonic' ways of adding this sort of information to a function. The two possibilities I have thought of are: Use a strict naming convention for arguments, and then infer stuff about them from their names (fetched using getargspec) Invent our own docstring meta-language (could be little more than CSV) and use the docstring for our metadata. Because Python seems pretty popular for building scripting into large apps, I imagine this is a solved problem with some common conventions, but I haven't been able to find them.

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  • Memory management of objects returned by methods (iOS / Objective-C)

    - by iOSNewb
    I am learning Objective-C and iOS programming through the terrific iTunesU course posted by Stanford (http://www.stanford.edu/class/cs193p/cgi-bin/drupal/) Assignment 2 is to create a calculator with variable buttons. The chain of commands (e.g. 3+x-y) is stored in a NSMutableArray as "anExpression", and then we sub in random values for x and y based on an NSDictionary to get a solution. This part of the assignment is tripping me up: The final two [methods] “convert” anExpression to/from a property list: + (id)propertyListForExpression:(id)anExpression; + (id)expressionForPropertyList:(id)propertyList; You’ll remember from lecture that a property list is just any combination of NSArray, NSDictionary, NSString, NSNumber, etc., so why do we even need this method since anExpression is already a property list? (Since the expressions we build are NSMutableArrays that contain only NSString and NSNumber objects, they are, indeed, already property lists.) Well, because the caller of our API has no idea that anExpression is a property list. That’s an internal implementation detail we have chosen not to expose to callers. Even so, you may think, the implementation of these two methods is easy because anExpression is already a property list so we can just return the argument right back, right? Well, yes and no. The memory management on this one is a bit tricky. We’ll leave it up to you to figure out. Give it your best shot. Obviously, I am missing something with respect to memory management because I don't see why I can't just return the passed arguments right back. Thanks in advance for any answers!

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  • What *is* an IPM.DistList?

    - by Jeremy
    I'm trying to get the recipient addresses within an IPM.DistList that is stored in a public folder (of type contacts) in Exchange 2003. The typeName of the object (once I get hold of it) is a Message (with a parent object being a Messages collection) and the messageType is "IPM.DistList". I can find all sorts of things about IPM.DistListItems, which you would think an IPM.DistList would contain, but there apparently isn't any documentation on the DistList (that I can find) and DistListItems documentation lists no parent possibilities in MSDN. I'll state it another way in case I've left you confused: We have an Exchange 2003 info store with Public Folders. Within those Public Folders is a [sub]folder (that holds items of type "Contact") that has a bunch of distribution lists (IPM.DistList's) that have contact entries, members of the list essentially. I need to get the addresses of the members of the lists in the Public Folder sub-folder using any VB language, because the company I work for hired me as a VB guy and expects me to write VB solutions, even though I could do it in C++... alas, I digress. VB is the language I'm supposed to figure this out in. (.net, script, vba, vb6, it doesn't matter which one. Yes, I know vb.net is not really related to those that came before, but they don't know that.) Anyone ran into anything like this? Am I just not finding the IPM.DistList documentation but it does actually exist somewhere? This isn't a Message.MAPIOBJECT (iUnknown) problem is it? Thanks.... Jeremy

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  • Rescuing a failed WCF call

    - by illdev
    Hello, I am happily using Castle's WcfFacility. From Monorail I know the handy concept of Rescues - consumer friendly results that often, but not necessarily, contain Data about what went wrong. I am creating a Silverlight application right now, doing quite a few WCF service calls. All these request return an implementation of public class ServiceResponse { private string _messageToUser = string.Empty; private ActionResult _result = ActionResult.Success; public ActionResult Result // Success, Failure, Timeout { get { return _result; } set { _result = value; } } public string MessageToUser { get { return _messageToUser; } set { _messageToUser = value; } } } public abstract class ServiceResponse<TResponseData> : ServiceResponse { public TResponseData Data { get; set; } } If the service has trouble responding the right way, I would want the thrown Exception to be intercepted and converted to the expected implementation. base on the thrown exception, I would want to pass on a nice message. here is how one of the service methods looks like: [Transaction(TransactionMode.Requires)] public virtual SaveResponse InsertOrUpdate(WarehouseDto dto) { var w = dto.Id > 0 ? _dao.GetById(dto.Id) : new Warehouse(); w.Name = dto.Name; _dao.SaveOrUpdate(w); return new SaveResponse { Data = new InsertData { Id = w.Id } }; } I need the thrown Exception for the Transaction to be rolled back, so i cannot actually catch it and return something else. Any ideas, where I could hook in?

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  • How do I get a less than in a javascript for loop in XSL to work?

    - by Kyle
    I am using CDATA to escape the script but in IE8's debugger I still get this message: "Expected ')'" in the for loop conditions. I am assuming it still thinks that the ; in the &lt; generated by CDATA is ending the loop conditions. Original script in my XSL template: <script type="text/javascript" language="javascript"> <![CDATA[ function submitform(form){ var oErrorArray = new Array(); for (i=0;i<form.length;i++) eval("oErrorArray["+i+"]=oError"+i); var goForm = true; for(i=0;i<form.length;i++) { oErrorArray[i].innerHTML = ""; if(form[i].value="")){ oErrorArray[i].innerHTML = "Error - input field is blank"; goForm = false; } } if(goForm == true) form.submit(); } function resetform(form){ form.reset(); } ]]> </script> Code generated after transformation (from IE8 debugger): <script type="text/javascript" language="javascript"> function submitform(form){ var oErrorArray = new Array(); for (i=0;i&lt;form.length;i++) eval("oErrorArray["+i+"]=oError"+i); goForm = true; for(i=0;i&lt;form.length;i++) { oErrorArray[i].innerHTML = ""; if(form[i].value="")){ oErrorArray[i].innerHTML = "Error - input field is blank"; goForm = false; } } if(goForm == true) form.submit(); } function resetform(form){ form.reset(); } </script> Error reported by IE8 debugger: Expected ')' login.xml, line 29 character 30 (which is right after the first "form.length")

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  • Display all feeds using simplexml_load() using PHP

    - by Jean
    Hello, I want to loop to get all feeds, but displaying only one $url = "http://localhost/feeds/feeds.rss"; $xml = simplexml_load_file($url); foreach($xml->item as $result){ echo $result->description."<br>"; } RSS Feed is - <channel> <title>/</title> <link>/</link> <atom:link type="application/rss+xml" href="/" rel="self"/> <description>/</description> <language>/</language> <ttl>/</ttl> <item> <title>/</title> <description>/</description> <pubDate>/</pubDate> <guid>/</guid> <link>/</link> </item> <item> <title>/</title> <description>/</description> <pubDate>/</pubDate> <guid>/</guid> <link>/</link> </item> </channel> Thanks Jean

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  • ASP.NET MVC - How to Unit Test boundaries in the Repository pattern?

    - by JK
    Given a basic repository interface: public interface IPersonRepository { void AddPerson(Person person); List<Person> GetAllPeople(); } With a basic implementation: public class PersonRepository: IPersonRepository { public void AddPerson(Person person) { ObjectContext.AddObject(person); } public List<Person> GetAllPeople() { return ObjectSet.AsQueryable().ToList(); } } How can you unit test this in a meaningful way? Since it crosses the boundary and physically updates and reads from the database, thats not a unit test, its an integration test. Or is it wrong to want to unit test this in the first place? Should I only have integration tests on the repository? I've been googling the subject and blogs often say to make a stub that implements the IRepository: public class PersonRepositoryTestStub: IPersonRepository { private List<Person> people = new List<Person>(); public void AddPerson(Person person) { people.Add(person); } public List<Person> GetAllPeople() { return people; } } But that doesnt unit test PersonRepository, it tests the implementation of PersonRepositoryTestStub (not very helpful).

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  • Custom UIProgressView drawing weirdness

    - by Werner
    I am trying to create my own custom UIProgressView by subclassing it and then overwrite the drawRect function. Everything works as expected except the progress filling bar. I can't get the height and image right. The images are both in Retina resolution and the Simulator is in Retina mode. The images are called: "[email protected]" (28px high) and "[email protected]" (32px high). CustomProgressView.h #import <UIKit/UIKit.h> @interface CustomProgressView : UIProgressView @end CustomProgressView.m #import "CustomProgressView.h" @implementation CustomProgressView - (id)initWithFrame:(CGRect)frame { self = [super initWithFrame:frame]; if (self) { // Initialization code } return self; } // Only override drawRect: if you perform custom drawing. // An empty implementation adversely affects performance during animation. - (void)drawRect:(CGRect)rect { // Drawing code self.frame = CGRectMake(self.frame.origin.x, self.frame.origin.y, self.frame.size.width, 16); UIImage *progressBarTrack = [[UIImage imageNamed:@"progressBarTrack"] resizableImageWithCapInsets:UIEdgeInsetsZero]; UIImage *progressBar = [[UIImage imageNamed:@"progressBar"] resizableImageWithCapInsets:UIEdgeInsetsMake(4, 4, 5, 4)]; [progressBarTrack drawInRect:rect]; NSInteger maximumWidth = rect.size.width - 2; NSInteger currentWidth = floor([self progress] * maximumWidth); CGRect fillRect = CGRectMake(rect.origin.x + 1, rect.origin.y + 1, currentWidth, 14); [progressBar drawInRect:fillRect]; } @end The resulting ProgressView has the right height and width. It also fills at the right percentage (currently set at 80%). But the progress fill image isn't drawn correctly. Does anyone see where I go wrong?

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  • How to load a type in parent-child website

    - by salvationishere
    I am developing a C# VS 2008 / SQL Server 2008 website. Although this same code compiles in the Project version, the website version does not compile. Many of their files are the same so I do not understand even where to look. The only compile error I get is: Could not load type 'DataMatch' in my DataMatch.aspx file. Is the problem in my web.config file? How do websites differ from projects in VS? All four of these files reside in same directory. Default.aspx file: <%@ Page Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="AddFileToSQL" Title="Untitled Page" % ... Default.aspx.cs file: ... using System.Data.SqlClient; using System.Security.Principal; namespace AddFileToSQL { public partial class AddFileToSQL : System.Web.UI.Page { ... DataMatch.aspx file: <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="DataMatch.aspx.cs" Inherits="DataMatch" % ... DataMatch.aspx.cs file: ... using System.Web.UI.WebControls; using AddFileToSQL; public partial class DataMatch : AddFileToSQL { ...

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  • C++ Matrix class hierachy

    - by bpw1621
    Should a matrix software library have a root class (e.g., MatrixBase) from which more specialized (or more constrained) matrix classes (e.g., SparseMatrix, UpperTriangluarMatrix, etc.) derive? If so, should the derived classes be derived publicly/protectively/privately? If not, should they be composed with a implementation class encapsulating common functionality and be otherwise unrelated? Something else? I was having a conversation about this with a software developer colleague (I am not per se) who mentioned that it is a common programming design mistake to derive a more restricted class from a more general one (e.g., he used the example of how it was not a good idea to derive a Circle class from an Ellipse class as similar to the matrix design issue) even when it is true that a SparseMatrix "IS A" MatrixBase. The interface presented by both the base and derived classes should be the same for basic operations; for specialized operations, a derived class would have additional functionality that might not be possible to implement for an arbitrary MatrixBase object. For example, we can compute the cholesky decomposition only for a PositiveDefiniteMatrix class object; however, multiplication by a scalar should work the same way for both the base and derived classes. Also, even if the underlying data storage implementation differs the operator()(int,int) should work as expected for any type of matrix class. I have started looking at a few open-source matrix libraries and it appears like this is kind of a mixed bag (or maybe I'm looking at a mixed bag of libraries). I am planning on helping out with a refactoring of a math library where this has been a point of contention and I'd like to have opinions (that is unless there really is an objective right answer to this question) as to what design philosophy would be best and what are the pros and cons to any reasonable approach.

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  • Beginner SQL section: avoiding repeated expression

    - by polygenelubricants
    I'm entirely new at SQL, but let's say that on the StackExchange Data Explorer, I just want to list the top 15 users by reputation, and I wrote something like this: SELECT TOP 15 DisplayName, Id, Reputation, Reputation/1000 As RepInK FROM Users WHERE RepInK > 10 ORDER BY Reputation DESC Currently this gives an Error: Invalid column name 'RepInK', which makes sense, I think, because RepInK is not a column in Users. I can easily fix this by saying WHERE Reputation/1000 > 10, essentially repeating the formula. So the questions are: Can I actually use the RepInK "column" in the WHERE clause? Do I perhaps need to create a virtual table/view with this column, and then do a SELECT/WHERE query on it? Can I name an expression, e.g. Reputation/1000, so I only have to repeat the names in a few places instead of the formula? What do you call this? A substitution macro? A function? A stored procedure? Is there an SQL quicksheet, glossary of terms, language specification, anything I can use to quickly pick up the syntax and semantics of the language? I understand that there are different "flavors"?

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  • cross-platform development for mobile devices

    - by user924
    What language/framework is best worth learning for mobile application development? My specific situation is that I'm very familiar with Java and C++ (I especially love Qt), but have limited experience with other languages. Some options I'm considering: 1) Learn Objective-C and all the iPhone-specific tools I do have access to a mac. The downside here is I'm restricted to the iPhone, so I'd have to rewrite almost everything if I wanted to branch off into another mobile device (or move later to a cross-platform framework). Even after knowing Objective-C, it seems like other frameworks might be more efficient/faster to code in? 2) Use some existing cross-platform framework for development I've looked at rhomobile, but I only have limited experience with Ruby (and at first glance, it might be a little pricey comapred to other options). Appcelerator also looks popular and nice, but it uses html/css/javascript. Airplaysdk looks good, but it's new and I haven't been able to see much written about it (is it worth going for?). 3) Wait for something better to come along How far away is Qt for the iPhone? That would be ideal, but it isn't available now. So what do you recommend? Productivity/efficiency is my top priority, although learning a useful language for the long term would also be okay. Thanks

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  • are C functions declared in <c____> headers gauranteed to be in the global namespace as well as std?

    - by Evan Teran
    So this is something that I've always wondered but was never quite sure about. So it is strictly a matter of curiosity, not a real problem. As far as I understand, what you do something like #include <cstdlib> everything (except macros of course) are declared in the std:: namespace. Every implementation that I've ever seen does this by doing something like the following: #include <stdlib.h> namespace std { using ::abort; // etc.... } Which of course has the effect of things being in both the global namespace and std. Is this behavior guaranteed? Or is it possible that an implementation could put these things in std but not in the global namespace? The only way I can think of to do that would be to have your libstdc++ implement every c function itself placing them in std directly instead of just including the existing libc headers (because there is no mechanism to remove something from a namespace). Which is of course a lot of effort with little to no benefit. The essence of my question is, is the following program strictly conforming and guaranteed to work? #include <cstdio> int main() { ::printf("hello world\n"); }

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  • Is there a definitive reference document for Ruby syntax?

    - by JSW
    I'm searching for a definitive document on Ruby syntax. I know about the definitive documents for the core API and standard library, but what about the syntax itself? For instance, such a document should cover: reserved words, string literals syntax, naming rules for variables/classes/modules, all the conditional statements and their permutations, and so forth. I know there are many books and tutorials, yes, but every one of them is essentially a tutorial, each one having a range of different depth and focus. They will all, by necessity of brevity and narrative flow, omit certain details of the language that the author deems insignificant. For instance, did you know that you can use a case statement without an initial case value, and it will then execute the first true when clause? Any given Ruby book or tutorial may or may not cover that particular lesser-known functionality of the case syntax. It's not discussed in the section in "Programming Ruby" about case statements. But that is just one small example. So far the best documentation I've found is the rubyspec project, which appears to be an attempt to write a complete test suite for the language. That's not bad, but it's a bit hard to use from a practical standpoint as a developer working on my own projects. Am I just missing something or is there really no definitive readable document defining the whole of Ruby syntax?

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  • Open closed prinicple, problem

    - by Marcus
    Hi, I'm trying to apply OCP to a code snippet I have that in it's current state is really smelly, but I feel I'm not getting all the way to the end. Current code: public abstract class SomeObject {} public class SpecificObject1 : SomeObject {} public class SpecificObject2 : SomeObject {} // Smelly code public class Model { public void Store(SomeObject someObject) { if (someObject is SpecificObject1) {} else if (someObject is SpecificObject2) {} } } That is really ugly, my new approach looks like this: // No so smelly code public class Model { public void Store(SomeObject someObject) { throw new Expception("Not allowed!"); } public void Store(SpecificObject1 someObject) {} public void Store(SpecificObject2 someObject) {} } When a new SomeObject type comes along I must implement how that specific object is stored, this will break OCP cause I need to alter the Model-class. To move the store logic to SomeObject also feels wrong cause then I will violate SRP (?), becuase in this case the SomeObject is almost like a DTO, it's resposibility it not how to know to store itself. If a new implementation to SomeObject comes along who's store implementation is missing I will get a runtime error due to exception in Store method in Model class, it also feels like a code smell. This is because calling code will in the form of IEnumerable<SomeObject> sequence; I will not know the specific types of the sequence objects. I can't seem to grasp the OCP-concept. Anyone has any concrete examples or links that is a bit more than just some Car/Fruit example?

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  • Learn Prolog Now! DCG Practice Example

    - by Timothy
    I have been progressing through Learn Prolog Now! as self-study and am now learning about Definite Clause Grammars. I am having some difficulty with one of the Practical Session's tasks. The task reads: The formal language anb2mc2mdn consists of all strings of the following form: an unbroken block of as followed by an unbroken block of bs followed by an unbroken block of cs followed by an unbroken block of ds, such that the a and d blocks are exactly the same length, and the c and d blocks are also exactly the same length and furthermore consist of an even number of cs and ds respectively. For example, ε, abbccd, and aaabbbbccccddd all belong to anb2mc2mdn. Write a DCG that generates this language. I am able to write rules that generate andn, b2mc2m, and even anb2m and c2mndn... but I can't seem to join all these rules into anb2mc2mdn. The following are my rules that can generate andn and b2mc2m. s1 --> []. s1 --> a,s1,d. a --> [a]. d --> [d]. s2 --> []. s2 --> c,c,s2,d,d. c --> [c]. d --> [d]. Is anb2mc2mdn really a CFG, and is it possible to write a DCG using only what was taught in the lesson (no additional arguments or code, etc)? If so, can anyone offer me some guidance how I can join these so that I can solve the given task?

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  • jquery append() method on empty XML element

    - by Anthony
    This could just be a syntax error, but I'm trying to create a Document object from scratch, starting with document.implementation.createDocument() and then using jquery's append() method to add the elements. But it's not appending: var myDoc = document.implementation.createDocument("", 'stuff', null); $("stuff",myDoc).attr("test","tested"); $("stuff",myDoc).append("<test>A</test>"); $("<test>B</test>").appendTo("stuff",soapEnv); var s = new XMLSerializer(); alert(s.serializeToString(soapEnv)); This should output: <stuff test="tested"> <test>A</test> <test>B</test> </stuff> But instead it outputs: <stuff test="tested" /> So the selector seems to be working, just not the method. My only guess is the method doesn't account for the fact that elements are empty (<stuff />) until they have children. But that's just a guess.

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  • Get Browser to send both If-None-Match and If-Modified-Since

    - by Glen
    My Browser isn't sending back an If-Modified-Since Header for PHP generated Content on the first request my script sends: (Status-Line) HTTP/1.1 200 OK Date Thu, 21 Jan 2010 08:55:25 GMT Server Apache/2.2.11 (Win32) PHP/5.2.9-1 X-Powered-By PHP/5.2.9-1 Pragma no-cache x-ua-compatible IE=8;FF=3;OtherUA=4 Last-Modfied Sat, 02 Jan 2010 02:02:20 GMT Content-Length 28453 Etag b98e0795b509be20146f58e06fbb624f Keep-Alive timeout=5, max=90 Connection Keep-Alive Content-Type image/png it on the second request it sends: (Request-Line) GET /kincumberunitingchurch/banner_image.php?id=1 HTTP/1.1 Host localhost User-Agent Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.0.17) Gecko/2009122116 Firefox/3.0.17 Accept image/png,image/*;q=0.8,*/*;q=0.5 Accept-Language en-us,en;q=0.5 Accept-Encoding gzip,deflate Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive 300 Connection keep-alive Referer http://localhost/kincumberunitingchurch/index.php?sid=tgl9jq3f71nau3cj9vps6pna03 Cookie sid=tgl9jq3f71nau3cj9vps6pna03; PHPSESSID=m0jvven6d7l65pl6odm9ecfnt4 If-None-Match b98e0795b509be20146f58e06fbb624f Cache-Control max-age=0 for other files the sever sends first: (Status-Line) HTTP/1.1 200 OK Date Thu, 21 Jan 2010 08:55:25 GMT Server Apache/2.2.11 (Win32) PHP/5.2.9-1 Last-Modified Wed, 30 Dec 2009 02:40:58 GMT Etag "1000000013d35-40d9-47be9117f6280" Accept-Ranges bytes Content-Length 16601 Keep-Alive timeout=5, max=84 Connection Keep-Alive Content-Type image/png and my browser send the following on the next request: (Request-Line) GET /kincumberunitingchurch/img/cbuttons.png HTTP/1.1 Host localhost User-Agent Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.0.17) Gecko/2009122116 Firefox/3.0.17 Accept image/png,image/*;q=0.8,*/*;q=0.5 Accept-Language en-us,en;q=0.5 Accept-Encoding gzip,deflate Accept-Charset ISO-8859-1,utf-8;q=0.7,*;q=0.7 Keep-Alive 300 Connection keep-alive Referer http://localhost/kincumberunitingchurch/mystyle.css Cookie sid=tgl9jq3f71nau3cj9vps6pna03; PHPSESSID=m0jvven6d7l65pl6odm9ecfnt4 If-Modified-Since Wed, 30 Dec 2009 02:40:58 GMT If-None-Match "1000000013d35-40d9-47be9117f6280" Cache-Control max-age=0 why would it send the If-Modified-Since header

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