Search Results

Search found 21559 results on 863 pages for 'template meta programming'.

Page 448/863 | < Previous Page | 444 445 446 447 448 449 450 451 452 453 454 455  | Next Page >

• Get control in code from ControlTemplate By Name

  - by Polaris

  Hello. I have next control template in my WPF app. <Style TargetType="Label" x:Key="LabelStyle"> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="Label"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition Width="40"/> <ColumnDefinition/> </Grid.ColumnDefinitions> <TextBox x:Name="MyTextBlock" Text="{TemplateBinding Content}" Height="20" HorizontalAlignment="Left" VerticalAlignment="Top" /> <Label Content="{TemplateBinding Content}" Grid.Column="1" Grid.Row="1"/> </Grid> </ControlTemplate> </Setter.Value> </Setter> </Style> TextBox "MyTextBlock" is invisible in C# code of window. How can I access to this textblock in code

  Read the article

• Confused about theme function calls.

  - by Nick Lowman

  I've created a content type that has a CCK text field. When I select the text field using the Drupal Themer widget it tells me the last function called was theme_text_formatter_default() , which I found in the CCK text.module It also tells me that it's parents were; content-field.tpl.php < theme_markup < theme_markup < node.tpl.php < page.tpl.php So I assumed that somewhere in the content-field.tpl.php was the function call to theme('text_formatter_default',$element) but it wasn't in there. Just print $item['view'] used to display the content. I searched all the project files for theme('text_formatter_default',$element) and it doesn't exist. I know it's being called by the theme function as I override it in my template.php and it used my overridden function, which would only happen if was using the theme_hook$. Wouldn't it? So how is it being called? It's not that I need to override it. I'm just learning how drupal works and thought I had it sussed until this. Something must be calling it. Also, the function theme_text_formatter_default exists in the theme registry and it's overridable (if that's a word) as I did so in my template.php and it displayed. It's all quite confusing. Any help would be much appreciated

  Read the article

• Is there a way to create subdatabases as a kind of subfolders in sql server?

  - by user193655

  I am creating an application where there is main DB and where other data is stored in secondary databases. The secondary databases follow a "plugin" approach. I use SQL Server. A simple installation of the application will just have the mainDB, while as an option one can activate more "plug-ins" and for every plug-in there will be a new database. Now why I made this choice is because I have to work with an exisiting legacy system and this is the smartest thing I could figure to implement the plugin system. MainDB and Plugins DB have exactly the same schema (basically Plugins DB have some "special content", some important data that one can use as a kind of template - think to a letter template for example - in the application). Plugin DBs are so used in readonly mode, they are "repository of content". The "smart" thing is that the main application can also be used by "plugin writers", they just write a DB inserting content, and by making a backup of the database they creaetd a potential plugin (this is why all DBs has the same schema). Those plugins DB are downloaded from internet as there is a content upgrade available, every time the full PlugIn DB is destroyed and a new one with the same name is creaetd. This is for simplicity and even because the size of this DBs is generally small. Now this works, anyway I would prefer to organize the DBs in a kind of Tree structure, so that I can force the PlugIn DBs to be "sub-DBs" of the main application DB. As a workaround I am thinking of using naming rules, like: ApplicationDB (for the main application DB) ApplicationDB_PlugIn_N (for the N-th plugin DB) When I search for plugin 1 I try to connect to ApplicationDB_PlugIn_1, if I don't find the DB i raise an error. This situation can happen for example if som DBA renamed ApplicationDB_Plugin_1. So since those Plugin DBs are really dependant on ApplicationDB only I was trying to "do the subfolder trick". Can anyone suggest a way to do this? Can you comment on this self-made plugin approach I decribed above?

  Read the article

• C++ templates error: instantiated from 'void TestClass::testMethod(T, std::map) [with T = SomeClass]

  - by pureconsciousness

  Hello there, I've some problem in my code I cannot deal with: #ifndef TESTCLASS_H_ #define TESTCLASS_H_' #include <map> using namespace std; template <typename T> class TestClass { public: TestClass(){}; virtual ~TestClass(){}; void testMethod(T b,std::map<T,int> m); }; template <typename T> void TestClass`<T`>::testMethod(T b,std::map<T,int> m){ m[b]=0; } #endif /*TESTCLASS_H_*/ int main(int argc, char* argv[]) { SomeClass s; TestClass<SomeClass> t; map<SomeClass,int> m; t.testMethod(s,m); } Compiler gives me following error in line m[b]=0; : instantiated from 'void TestClass::testMethod(T, std::map) [with T = SomeClass] Could you help find the problem?? Thanks in advance

  Read the article

• SFINAE and detecting if a C++ function object returns void.

  - by Tom Swirly

  I've read the various authorities on this, include Dewhurst and yet haven't managed to get anywhere with this seemingly simple question. What I want to do is to call a C++ function object, (basically, anything you can call, a pure function or a class with ()), and return its value, if that is not void, or "true" otherwise. #include <stdio.h> struct Foo { void operator()() {} }; struct Bar { bool operator()() { return false; } }; Foo foo; Bar bar; bool baz() { return false; } void bang() {} const char* print(bool b) { printf(b ? "true, " : "false, "); } template <typename Functor> bool magicCallFunction(Functor f) { return true; // lots of template magic occurs here... } int main(int argc, char** argv) { print(magicCallFunction(foo)); print(magicCallFunction(bar)); print(magicCallFunction(baz)); print(magicCallFunction(bang)); printf("\n"); }

  Read the article

• XSLT: change node inner text.

  - by nabo

  I need to transform the following xml doc: <a> <b/> <c/> myText </a> into this: <a> <b/> <c/> differentText </a> So, i wrote this XSLT document <xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0"> <xsl:output method="xml" version="1.0" omit-xml-declaration="no" /> <xsl:template match="/a/text()"> <a> <b/> <c/> differentText </a> </xsl:template> </xsl:stylesheet> This way, i get the following result: <?xml version="1.0" encoding="utf-8"?> <a> <b /><c /> differentText </a> <a> <b /><c /> differentText </a> <a> <b /><c /> differentText </a> The result appears repeated 3 times because 3 matches are being done.. Why? I could i fix it? Thanks

  Read the article

• Need help optimizing this Django aggregate query

  - by Chris Lawlor

  I have the following model class Plugin(models.Model): name = models.CharField(max_length=50) # more fields which represents a plugin that can be downloaded from my site. To track downloads, I have class Download(models.Model): plugin = models.ForiegnKey(Plugin) timestamp = models.DateTimeField(auto_now=True) So to build a view showing plugins sorted by downloads, I have the following query: # pbd is plugins by download - commented here to prevent scrolling pbd = Plugin.objects.annotate(dl_total=Count('download')).order_by('-dl_total') Which works, but is very slow. With only 1,000 plugins, the avg. response is 3.6 - 3.9 seconds (devserver with local PostgreSQL db), where a similar view with a much simpler query (sorting by plugin release date) takes 160 ms or so. I'm looking for suggestions on how to optimize this query. I'd really prefer that the query return Plugin objects (as opposed to using values) since I'm sharing the same template for the other views (Plugins by rating, Plugins by release date, etc.), so the template is expecting Plugin objects - plus I'm not sure how I would get things like the absolute_url without a reference to the plugin object. Or, is my whole approach doomed to failure? Is there a better way to track downloads? I ultimately want to provide users some nice download statistics for the plugins they've uploaded - like downloads per day/week/month. Will I have to calculate and cache Downloads at some point? EDIT: In my test dataset, there are somewhere between 10-20 Download instances per Plugin - in production I expect this number would be much higher for many of the plugins.

  Read the article

• Problem with Java FX Look and Feel

  - by drachenfels

  Hi, I was looking at some of the examples from the Deitel and Deitel's book for Programming in Java, and one of the first examples is a very simple Swing display. Hence this snippet of code : import javax.swing.*; public class cdea { public static void main(String args[]){ JOptionPane.showMessageDialog(null,"\"Welcome to Java Programming!\""); System.exit(0); //end method main } } I read some stuff regarding how one can get native UI look and feel by using UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName()); to the program. However, when I just add this to my main method, it gives me a host of errors. Specifically : Multiple markers at this line - Unhandled exception type IllegalAccessException - Unhandled exception type InstantiationException - Unhandled exception type ClassNotFoundException - Unhandled exception type UnsupportedLookAndFeelException However when I use it as part of a try/catch exception loop (is that what it is called?) as detailed on http://stackoverflow.com/questions/1590863/getting-java-applications-to-look-native-on-windows-how , I get the program running properly. Could anyone tell me in simple language why this is so? As in, why can't I directly get the System look and feel; why do I have to use it with exception handling? I'm new to Java, and OOP in general, so I'm sorry if I'm being too simplistic.

  Read the article

• in haskell, why do I need to specify type constraints, why can't the compiler figure them out?

  - by Steve

  Consider the function, add a b = a + b This works: *Main> add 1 2 3 However, if I add a type signature specifying that I want to add things of the same type: add :: a -> a -> a add a b = a + b I get an error: test.hs:3:10: Could not deduce (Num a) from the context () arising from a use of `+' at test.hs:3:10-14 Possible fix: add (Num a) to the context of the type signature for `add' In the expression: a + b In the definition of `add': add a b = a + b So GHC clearly can deduce that I need the Num type constraint, since it just told me: add :: Num a => a -> a -> a add a b = a + b Works. Why does GHC require me to add the type constraint? If I'm doing generic programming, why can't it just work for anything that knows how to use the + operator? In C++ template programming, you can do this easily: #include <string> #include <cstdio> using namespace std; template<typename T> T add(T a, T b) { return a + b; } int main() { printf("%d, %f, %s\n", add(1, 2), add(1.0, 3.4), add(string("foo"), string("bar")).c_str()); return 0; } The compiler figures out the types of the arguments to add and generates a version of the function for that type. There seems to be a fundamental difference in Haskell's approach, can you describe it, and discuss the trade-offs? It seems to me like it would be resolved if GHC simply filled in the type constraint for me, since it obviously decided it was needed. Still, why the type constraint at all? Why not just compile successfully as long as the function is only used in a valid context where the arguments are in Num? Thank you.

  Read the article

• Coding the R-ight way - avoiding the for loop

  - by mropa

  I am going through one of my .R files and by cleaning it up a little bit I am trying to get more familiar with writing the code the r-ight way. As a beginner, one of my favorite starting points is to get rid of the for() loops and try to transform the expression into a functional programming form. So here is the scenario: I am assembling a bunch of data.frames into a list for later usage. dataList <- list (dataA, dataB, dataC, dataD, dataE ) Now I like to take a look at each data.frame's column names and substitute certain character strings. Eg I like to substitute each "foo" and "bar" with "baz". At the moment I am getting the job done with a for() loop which looks a bit awkward. colnames(dataList[[1]]) [1] "foo" "code" "lp15" "bar" "lh15" colnames(dataList[[2]]) [1] "a" "code" "lp50" "ls50" "foo" matchVec <- c("foo", "bar") for (i in seq(dataList)) { for (j in seq(matchVec)) { colnames (dataList[[i]])[grep(pattern=matchVec[j], x=colnames (dataList[[i]]))] <- c("baz") } } Since I am working here with a list I thought about the lapply function. My attempts handling the job with the lapply function all seem to look alright but only at first sight. If I write f <- function(i, xList) { gsub(pattern=c("foo"), replacement=c("baz"), x=colnames(xList[[i]])) } lapply(seq(dataList), f, xList=dataList) the last line prints out almost what I am looking for. However, if i take another look at the actual names of the data.frames in dataList: lapply (dataList, colnames) I see that no changes have been made to the initial character strings. So how can I rewrite the for() loop and transform it into a functional programming form? And how do I substitute both strings, "foo" and "bar", in an efficient way? Since the gsub() function takes as its pattern argument only a character vector of length one.

  Read the article

• What happens when you create an instance of an object containing no state in C#?

  - by liquorice

  I am I think ok at algorithmic programming, if that is the right term? I used to play with turbo pascal and 8086 assembly language back in the 1980s as a hobby. But only very small projects and I haven't really done any programming in the 20ish years since then. So I am struggling for understanding like a drowning swimmer. So maybe this is a very niave question or I'm just making no sense at all, but say I have an object kind of like this: class Something : IDoer { void Do(ISomethingElse x) { x.DoWhatEverYouWant(42); } } And then I do var Thing1 = new Something(); var Thing2 = new Something(); Thing1.Do(blah); Thing2.Do(blah); does Thing1 = Thing2? does "new Something()" create anything? Or is it not much different different from having a static class, except I can pass it around and swap it out etc. Is the "Do" procedure in the same location in memory for both the Thing1(blah) and Thing2(blah) objects? I mean when executing it, does it mean there are two Something.Do procedures or just one?

  Read the article

• C++ IDE for Linux?

  - by Sven

  I want to expand my programming horizons to Linux. A good, dependable basic toolset is important, and what is more basic than an IDE? I could find these SO topics: Lightweight IDE for linux and What tools do you use to develop C++ applications on Linux? I'm not looking for a lightweight IDE. If an IDE is worth the money, then I will pay for it, so it need not be free. My question, then: What good, C++ programming IDE is available for Linux? The minimums are fairly standard: syntax highlighting, code completion (like intellisense or its Eclipse counterpart) and integrated debugging (e.g., basic breakpoints). I have searched for it myself, but there are so many that it is almost impossible to separate the good from the bads by hand, especially for someone like me who has little C++ coding experience in Linux. I know that Eclipse supports C++, and I really like that IDE for Java, but is it any good for C++ and is there something better? The second post actually has some good suggestions, but what I am missing is what exactly makes the sugested IDE so good for the user, what are its (dis)advantages? Maybe my question should therefore be: What IDE do you propose (given your experiences), and why?

  Read the article

• Website displays in chrome perfectly, but not in mozilla or IE

  - by Atharul Khan

  here are the code snippets for the html and css. It works finds in Google chrome, but when I try to display it in mozilla or IE, it shows something completely different. I cannot attach images as I do not have the required reputation. I really appreciate the help. Thank you! HTML <!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <meta http-equiv="Content-type" content="text/html; charset=utf-8" /> <meta name="viewport" content="width=device-width, initial-scale=1" /> <link rel="stylesheet" type="text/css" href="style.css"> <link rel="shortcut icon" href="ak.png"> <title>Home</title> </head> <body> <div class="Nav"> <nav> <ul class="navigation fade-in2"> <li><a href="#home">Home</a></li> <li><a href="#about">About</a></li> <li><a href="#portfolio">Portfolio</a></li> <li><a href="#shop">Shop</a></li> <li><a href="#blog">Blog</a></li> <li><a href="#contact">Contact</a></li> </ul> </nav> </div> <div class="logo"><a href="#home"><img class="ak fade-in2" src="ak.png"></a></div> <div class="background"><img class="beauty" src="beauty.jpg"></div> <div class="header"> <h1 class="headerName fade-in">DESIGN | DEVELOP | BRAND</h1> <h4 class="service fade-in3"><a href="#portfolio">VIEW PORTFOLIO</a></h4> <h4 class="service fade-in3"><a href="#services">VIEW SERVICES</a></h4> </div> <!--<div class="mainbody"><p>safsdaf</p></div>--> </body> </html> CSS @-webkit-keyframes fadeIn { from { opacity:0; } to { opacity:1; } } @-moz-keyframes fadeIn { from { opacity:0; } to { opacity:1; } } @keyframes fadeIn { from { opacity:0; } to { opacity:1; } } * { padding: 0; margin: 0; } li { display: inline; font-size: 15px; font-family: verdana; } nav { width: 100%; text-align: right; background-color: #222222; padding: 0; margin: 0px; line-height: 47px; position: fixed; z-index: 100; } .ak{ width: 90px; height: 55px; z-index: 101; position: fixed; background: transparent; color: transparent; background-color: transparent; } .Nav a{ text-decoration: none; padding: 15px; } .Nav a:link{ color: #A7A7A7; } .Nav a:visited{ color: #A7A7A7; } .Nav a:hover{ color: #DBDBDB; transition: all 0.3s ease-out 0s; transition-property: all; transition-duration: 0.3s; transition-timing-function: ease-out; transition-delay: 0s; } .header { background-color: rgba(0,0,0, 0.25); width: 100%; height: 626px; text-align: center; position: fixed; z-index: 10; } .background { position: fixed; z-index: 8; } .beauty { width: 100%; height: 626px; } .headerName { font-size: 2.5em; text-align: center; color: #D3D3D3; padding: 180px; padding-bottom: 50px; margin: 0px; letter-spacing: 4px; font-weight: 100; font-family: 'Lato', sans-serif; } .fade-in { opacity:0; /* make things invisible upon start */ -webkit-animation:fadeIn ease-in 1; /* call our keyframe named fadeIn, use animation ease-in and repeat it only 1 time */ -moz-animation:fadeIn ease-in 1; animation:fadeIn ease-in 1; -webkit-animation-fill-mode:forwards; /* this makes sure that after animation is done we remain at the last keyframe value (opacity: 1)*/ -moz-animation-fill-mode:forwards; animation-fill-mode:forwards; -webkit-animation-duration:1s; -moz-animation-duration:1s; animation-duration:1s; -webkit-animation-delay: 0.3s; -moz-animation-delay:0.3s; animation-delay: 0.3s; } .fade-in2 { opacity:0; /* make things invisible upon start */ -webkit-animation:fadeIn ease-in 1; /* call our keyframe named fadeIn, use animation ease-in and repeat it only 1 time */ -moz-animation:fadeIn ease-in 1; animation:fadeIn ease-in 1; -webkit-animation-fill-mode:forwards; /* this makes sure that after animation is done we remain at the last keyframe value (opacity: 1)*/ -moz-animation-fill-mode:forwards; animation-fill-mode:forwards; -webkit-animation-duration:1s; -moz-animation-duration:1s; animation-duration:1s; -webkit-animation-delay: 0.6s; -moz-animation-delay:0.6s; animation-delay: 0.6s; } .fade-in3 { opacity:0; /* make things invisible upon start */ -webkit-animation:fadeIn ease-in 1; /* call our keyframe named fadeIn, use animation ease-in and repeat it only 1 time */ -moz-animation:fadeIn ease-in 1; animation:fadeIn ease-in 1; -webkit-animation-fill-mode:forwards; /* this makes sure that after animation is done we remain at the last keyframe value (opacity: 1)*/ -moz-animation-fill-mode:forwards; animation-fill-mode:forwards; -webkit-animation-duration:1s; -moz-animation-duration:1s; animation-duration:1s; -webkit-animation-delay: 0.9s; -moz-animation-delay:0.9s; animation-delay: 0.9s; } .service{ font-size: 14px; width: 190px; text-align: center; font-family: 'Lato', sans-serif; color: #D3D3D3; border: 2px #A7A7A7 solid; border-color: rgba(255, 255, 255, 0.5); display: inline-block; border-radius: 5px; background-color: transparent; letter-spacing: 2px; } .service a{ text-decoration: none; display: block; padding: 15px 20px; } .service a:link{ color: #D3D3D3; } .service a:visited{ color: #D3D3D3; } .service a:hover{ background-color: rgba(255, 255, 255, 0.15); transition: background-color .15s ease-in; -webkit-transition: background-color .15s ease-in; -moz-transition: background-color .15s ease-in; -o-transition: background-color .15s ease-in; } UPDATE 1: I updated both browsers and it seems the css3 animations work perfectly fine on both browsers. What seems to be the problem is the positioning of the pages UPDATE 2: Here are the links to the different browser screen shots Chrome: https://www.dropbox.com/s/jlpa4vu51kdnews/Chrome.JPG InternetExplorer: https://www.dropbox.com/s/zbchs3su9ahxr0n/IE.JPG Mozilla Firefox: dropbox(.)com/s/fyalnhsha9ktadz/Mozilla.JPG (I can't post the third link because I don't have enough reputation)

  Read the article

• Get current node's local-name in XSL

  - by green67

  Here's the structure of my XML <FileRoot> <UserSet1> <User> <FirstName></FirstName> <LastName></LastName> </User> <User> <FirstName></FirstName> <LastName></LastName> </User> ... </UserSet1> <InactiveUsers> <User> <FirstName></FirstName> <LastName></LastName> </User> <User> <FirstName></FirstName> <LastName></LastName> </User> ... </InactiveUsers> </FileRoot> In my XSL template <xsl:template match="/*/*"> <File> <xsl attribute name="Name"> <xsl:value-of select="local-name(/*/*)"/> </xsl:attribute> </File> </xsl> After transforming, for both UserSet1 and InactiveUsers, gave me "UserSet1". The expected results should be "UserSet1" for UserSet1, and "InactiveUsers" for InactiveUsers. How do I correctly retrieve the value? Thanks

  Read the article

• Create a subtitle for menu items in Silverstripe CMS?

  - by ELF

  Hi I'm using Silverstripe CMS on the "Simple" template. I'm wondering how to create subtitles for the menu items. The current navigation template is like so: <nav class="primary"> <span class="nav-open-button">²</span> <ul> <% loop $Menu(2) %> <li class="$LinkingMode"><a href="$Link" title="$Title.XML">$MenuTitle.XML</a></li> <% end_loop %> </ul> I'm thinking i could somehow edit $Menutitle.XML but how? Also the sub title should be displayed directly under the Title but as the same button. The SubTitle would need to have a different css rule so that it could be smaller. I know that the CMS has an area for me to edit the page titles which become the menu titles, would it be easy to add a subtitle to the admin like that or is there some other easier way? I only need to make a few of them.

  Read the article

• C++ traits question

  - by duli

  I have a templated class template <typename Data> class C { ..... } In most situations, I depend on the compiler to let me substitute types for Data. I call methods foo(), goo() on objects of type Data, so what I substitute needs to provide that. I now need to substitute int and string for my Data type. I do not want to specialize because the class is already too big and would require specializing each method (with only small code change). My options (please tell me if there are more) 1) I can provide wrapper classes around int and string which implement the methods foo(), goo() etc 2) provide a traits class traits that calls foo() or goo() on objects of classes that provide foo(),goo() (these are my present substitutable classes) and specialize these classes for int and string. Questions 1) what are the relative merits of 1 vs 2? 2) My traits classes will have static methods. Can a traits class have non-static methods as well? I see most traits classes define constants in the STL. 3) Do I make the traits classes global or should I pass them in as a template parameter for class C?

  Read the article

• C++: Trouble with dependent types in templates

  - by Rosarch

  I'm having trouble with templates and dependent types: namespace Utils { void PrintLine(const string& line, int tabLevel = 0); string getTabs(int tabLevel); template<class result_t, class Predicate> set<result_t> findAll_if(typename set<result_t>::iterator begin, set<result_t>::iterator end, Predicate pred) // warning C4346 { set<result_t> result; return findAll_if_rec(begin, end, pred, result); } } namespace detail { template<class result_t, class Predicate> set<result_t> findAll_if_rec(set<result_t>::iterator begin, set<result_t>::iterator end, Predicate pred, set<result_t> result) { typename set<result_t>::iterator nextResultElem = find_if(begin, end, pred); if (nextResultElem == end) { return result; } result.add(*nextResultElem); return findAll_if_rec(++nextResultElem, end, pred, result); } } Compiler complaints, from the location noted above: warning C4346: 'std::set<result_t>::iterator' : dependent name is not a type. prefix with 'typename' to indicate a type error C2061: syntax error : identifier 'iterator' What am I doing wrong?

  Read the article

• How to reference {{outlet}} in Ember.CollectionView's itemView

  - by ceed

  I am new to ember and ran into a problem and could not find an answer online. I have a collectionView App.MyView = Ember.CollectionView.extend({ itemViewClass: 'App.MyViewItem', contentBinding: 'controller' }); and the itemViewClass App.MyViewItem = Ember.View.extend({ templateName: 'mytemplate' }); the template looks like that: <div {{action 'select' view.content}}>{{view.content.name}}</div> {{outlet detail}} </div> This produces the content list just fine. In the controller, I have an action: select: function(evt){ this.transitionToRoute('item', evt); } What I want to do is to transition to a nested route when selecting the item (which works fine) and also load more data of the selected item into {{outlet detail}}. While I can load the content of the "item" route into an outlet of e.g. application.hbs, I don't know how to reference the outlet of the selected collectionView item so that the detailed contents are displayed within the existing view. I tried to use: this.render('item', { outlet: 'detail', into: '????' }); within the item Route, but I don't know how to reference the collectionview item template. Maybe there's also a much easier way of loading more data from an item in the item's view (while changing the route at the same time). Any help would be appreciated.

  Read the article

• Practice of checking 'trueness' or 'equality' of conditional statements - does it really make sense?

  - by senthilkumar1033

  I remember many years back, when I was in school, one of my computer science teachers taught us that it was better to check for 'trueness' or 'equality' of a condition and not the negative stuff like 'inequality'. Let me elaborate - If a piece of conditional code can be written by checking whether an expression is true or false, we should check the 'trueness'. Example: Finding out whether a number is odd - it can be done in two ways: if ( num % 2 != 0 ) { // Number is odd } or if ( num % 2 == 1 ) { // Number is odd } When I was beginning to code, I knew that num % 2 == 0 implies the number is even, so I just put a ! there to check if it is odd. But he was like 'Don't check NOT conditions. Have the practice of checking the 'trueness' or 'equality' of conditions whenever possible.' And he recommended that I use the second piece of code. I am not for or against either but I just wanted to know - what difference does it make? Please don't reply 'Technically the output will be the same' - we ALL know that. Is it a general programming practice or is it his own programming practice that he is preaching to others?

  Read the article

• STLifying C++ classes

  - by shambulator

  I'm trying to write a class which contains several std::vectors as data members, and provides a subset of vector's interface to access them: class Mesh { public: private: std::vector<Vector3> positions; std::vector<Vector3> normals; // Several other members along the same lines }; The main thing you can do with a mesh is add positions, normals and other stuff to it. In order to allow an STL-like way of accessing a Mesh (add from arrays, other containers, etc.), I'm toying with the idea of adding methods like this: public: template<class InIter> void AddNormals(InIter first, InIter last); Problem is, from what I understand of templates, these methods will have to be defined in the header file (seems to make sense; without a concrete iterator type, the compiler doesn't know how to generate object code for the obvious implementation of this method). Is this actually a problem? My gut reaction is not to go around sticking huge chunks of code in header files, but my C++ is a little rusty with not much STL experience outside toy examples, and I'm not sure what "acceptable" C++ coding practice is on this. Is there a better way to expose this functionality while retaining an STL-like generic programming flavour? One way would be something like this: (end list) class RestrictedVector<T> { public: RestrictedVector(std::vector<T> wrapped) : wrapped(wrapped) {} template <class InIter> void Add(InIter first, InIter last) { std::copy(first, last, std::back_insert_iterator(wrapped)); } private: std::vector<T> wrapped; }; and then expose instances of these on Mesh instead, but that's starting to reek a little of overengineering :P Any advice is greatly appreciated!

  Read the article

• XSLT, process elements one by one

  - by qui

  Hi I am quite weak at XSLT so this might seem obvious. Here is some sample XML <term> <name>cholecystocolonic fistula</name> <definition>blah blah</definition> <reference>cholecystocolostomy</reference> </term> And here is the XSLT I wrote a while ago to process it <xsl:template name="term"> { "dictitle": "<xsl:value-of select="name" disable-output-escaping="yes" />", "html": "<xsl:value-of select="definition" disable-output-escaping="yes"/>", "referece": "<xsl:value-of select="reference" disable-output-escaping="yes"/> } </xsl:template> Basically I am creating JSON from the XML. The requirements have now changed so that now the XML can have more than one definition tag and reference tag. They can appear in any order, i.e definition, reference, reference, definition, reference. How can I update the XSLT to accommodate this? Probably worth mentioning that because my XSLT processor is using .NET I can only use XSLT 1.0 commands. Many thanks!

  Read the article

• Testing variable types in Python

  - by Jasper

  Hello, I'm creating an initialising function for the class 'Room', and found that the program wouldn't accept the tests I was doing on the input variables. Why is this? def __init__(self, code, name, type, size, description, objects, exits): self.code = code self.name = name self.type = type self.size = size self.description = description self.objects = objects self.exits = exits #Check for input errors: if type(self.code) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 110' elif type(self.name) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 111' elif type(self.type) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 112' elif type(self.size) != type(int()): print 'Error found in module rooms.py!' print 'Error number: 113' elif type(self.description) != type(str()): print 'Error found in module rooms.py!' print 'Error number: 114' elif type(self.objects) != type(list()): print 'Error found in module rooms.py!' print 'Error number: 115' elif type(self.exits) != type(tuple()): print 'Error found in module rooms.py!' print 'Error number: 116' When I run this I get this error: Traceback (most recent call last): File "/Users/Jasper/Development/Programming/MyProjects/Game Making Challenge/Europa I/rooms.py", line 148, in <module> myRoom = Room(101, 'myRoom', 'Basic Room', 5, '<insert description>', myObjects, myExits) File "/Users/Jasper/Development/Programming/MyProjects/Game Making Challenge/Europa I/rooms.py", line 29, in __init__ if type(self.code) != type(str()): TypeError: 'str' object is not callable

  Read the article

• reverse many to many fields in Django + count them

  - by cleliodpaula

  I'm trying to figure out how to solve this class Item(models.Model): type = models.ForeignKey(Type) name = models.CharField(max_lenght = 10) ... class List(models.Model): items = models.ManyToManyField(Item) ... I want to count how many an Item appears in another Lists, and show on template. view def items_by_list(request, id_): list = List.objects.get(id = id_) qr = list.items.all() #NOT TESTED num = [] i = 0 for item in qr: num[i] = List.objects.filter(items__id = item__id ).count() #FINISH NOT TESTED c = {} c.update(csrf(request)) c = {'request':request, 'list' : qr, 'num' : num} return render_to_response('items_by_list.html', c, context_instance=RequestContext(request)) template {% for dia in list %} <div class="span4" > <div> <h6 style="color: #9937d8">{{item.type.description}}</h6> <small style="color: #b2e300">{{ item.name }}</small> <small style="color: #b2e300">{{COUNT HOW MANY TIMES THE ITEM APPEAR ON OTHER LISTS}}</small> </div> {% endfor %} This seems to be easy, but I could not implement yet. If anyone has some glue to me, please help me. Thanks in advance.

  Read the article

• How to use different providers for Linq to entities?

  - by Anders Svensson

  I'm trying to familiarize myself a bit more with database programming, and I'm looking at different ways of creating a data access layer for applications. I've tried out a few ways but there is such a jungle of different database technologies that I don't know what to learn. For instance I've tried using datasets with tableadapters. Using that I am able to switch data provider rather easily (by programming against the interfaces such as IDbConnection). This is one thing I would want to achieve. But I also know everyone's talking about LINQ, and I'm trying to get to know that a bit better too. So I have tried using Linq to Sql classes as the data access layer as well, but apparently this is not provider independent (works only for SQL Server). So then I read about the Entity Framework (which just as Linq to SQL apparently has gotten its share of bashing already...). It's supposed to be provider independent everybody says, but how? I tried out a tutorial to create an entity data model, but the only providers to choose from were SQL Server/Express. Just for learning purposes, I would like to know how to use the entity framework with MS Access/OleDb. Also, I would appreciate some input on what is the preferred database technology for data access. Is it LINQ still after all the bashing, or should you just use datasets because they are provider independent? Any pointers for what to learn would be great, because it's just too much to learn it all if I'm not going to use it in the end...!

  Read the article

• How to synchronize access to many objects

  - by vividos

  I have a thread pool with some threads (e.g. as many as number of cores) that work on many objects, say thousands of objects. Normally I would give each object a mutex to protect access to its internals, lock it when I'm doing work, then release it. When two threads would try to access the same object, one of the threads has to wait. Now I want to save some resources and be scalable, as there may be thousands of objects, and still only a hand full of threads. I'm thinking about a class design where the thread has some sort of mutex or lock object, and assigns the lock to the object when the object should be accessed. This would save resources, as I only have as much lock objects as I have threads. Now comes the programming part, where I want to transfer this design into code, but don't know quite where to start. I'm programming in C++ and want to use Boost classes where possible, but self written classes that handle these special requirements are ok. How would I implement this? My first idea was to have a boost::mutex object per thread, and each object has a boost::shared_ptr that initially is unset (or NULL). Now when I want to access the object, I lock it by creating a scoped_lock object and assign it to the shared_ptr. When the shared_ptr is already set, I wait on the present lock. This idea sounds like a heap full of race conditions, so I sort of abandoned it. Is there another way to accomplish this design? A completely different way?

  Read the article

< Previous Page | 444 445 446 447 448 449 450 451 452 453 454 455  | Next Page >