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Search found 50304 results on 2013 pages for 'class variables'.

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  • functional dependencies vs type families

    - by mhwombat
    I'm developing a framework for running experiments with artificial life, and I'm trying to use type families instead of functional dependencies. Type families seems to be the preferred approach among Haskellers, but I've run into a situation where functional dependencies seem like a better fit. Am I missing a trick? Here's the design using type families. (This code compiles OK.) {-# LANGUAGE TypeFamilies, FlexibleContexts #-} import Control.Monad.State (StateT) class Agent a where agentId :: a -> String liveALittle :: Universe u => a -> StateT u IO a -- plus other functions class Universe u where type MyAgent u :: * withAgent :: (MyAgent u -> StateT u IO (MyAgent u)) -> String -> StateT u IO () -- plus other functions data SimpleUniverse = SimpleUniverse { mainDir :: FilePath -- plus other fields } defaultWithAgent :: (MyAgent u -> StateT u IO (MyAgent u)) -> String -> StateT u IO () defaultWithAgent = undefined -- stub -- plus default implementations for other functions -- -- In order to use my framework, the user will need to create a typeclass -- that implements the Agent class... -- data Bug = Bug String deriving (Show, Eq) instance Agent Bug where agentId (Bug s) = s liveALittle bug = return bug -- stub -- -- .. and they'll also need to make SimpleUniverse an instance of Universe -- for their agent type. -- instance Universe SimpleUniverse where type MyAgent SimpleUniverse = Bug withAgent = defaultWithAgent -- boilerplate -- plus similar boilerplate for other functions Is there a way to avoid forcing my users to write those last two lines of boilerplate? Compare with the version using fundeps, below, which seems to make things simpler for my users. (The use of UndecideableInstances may be a red flag.) (This code also compiles OK.) {-# LANGUAGE MultiParamTypeClasses, FunctionalDependencies, FlexibleInstances, UndecidableInstances #-} import Control.Monad.State (StateT) class Agent a where agentId :: a -> String liveALittle :: Universe u a => a -> StateT u IO a -- plus other functions class Universe u a | u -> a where withAgent :: Agent a => (a -> StateT u IO a) -> String -> StateT u IO () -- plus other functions data SimpleUniverse = SimpleUniverse { mainDir :: FilePath -- plus other fields } instance Universe SimpleUniverse a where withAgent = undefined -- stub -- plus implementations for other functions -- -- In order to use my framework, the user will need to create a typeclass -- that implements the Agent class... -- data Bug = Bug String deriving (Show, Eq) instance Agent Bug where agentId (Bug s) = s liveALittle bug = return bug -- stub -- -- And now my users only have to write stuff like... -- u :: SimpleUniverse u = SimpleUniverse "mydir"

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  • Action property of interface type

    - by Daniel
    Hi, guys. With my understading, the nature of a Action is that properties can be pushed w/ request parameter values. And, one wonderful feature is that Struts2 allows you to directly populate parameter values against Class type property ;) Assuming there exists a Action and property class as below, class Action extends ActionSupport { User user; @Action(value="hello" {@result=(.......)}) public void execute() { ........ } ..... public void setUser(User user) { this.user = user; } public User getUser() { return this.user; } } class User { String name; ..... public void setName(String name) { this.name = name; } public String getName() { return this.name; } } you could populate User class property by doing like this. http://...../hello.action?user.name=John or via jsp page Then, I realize that there are actually people make an Action property as a Interface type. My question is what is the reason behind this. If there is a sample code demonstrating it will be great. Thanks in advance!

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  • gcc problem with explicit template instantiation?

    - by steve jaffe
    It is my understanding that either a declaration or typedef of a specialization ought to cause a template class to be instantiated, but this does not appear to be happening with gcc. E.g. I have a template class, template class Foo {}; I write class Foo<double>; or typedef Foo<double> DoubleFoo; but after compilation the symbol table of the resulting object file does not contain the members of Foo. If I create an instance: Foo<double> aFoo; then of course the symbols are all generated. Has anyone else experienced this and/or have an explanation?

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  • Can't resolve CalledFromWrongThreadException with Handler

    - by michel
    I will try to keep it simple: In my main activity I make a handler: public class ARViewer extends ARDisplayActivity { public final MHandler mHandler = new MHandler(this); public void onCreate(Bundle savedInstanceState) { ... The class MHandler: public final class MHandler extends Handler{ //main activity private ARViewer arnv; public MHandler(ARViewer arnv){ this.arnv = arnv; } @Override public void handleMessage(Message msg) { ... case H_RR : arnv.setContentView(R.layout.routeplanner); break; ... super.handleMessage(msg); } } But if I call the handleMessage method from a callback function in a other Class, definitely from a other thread, I still get the exception message: CalledFromWrongThreadException (Only the original thread that created a view hierarchy can touch its views) : public void rFound(Route route) { Message msg = new Message(); msg.what = MHandler.H_RR; ARViewer.arnv.mHandler.handleMessage(msg); }

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  • java: "downcasting" to new object / opposite of slicing

    - by rhavin
    Sorry, i really dont know how to make a headline for that question; maybe there is a name for what im trying to do that i dont know, but i can explain it with some code: Guess you have a class that unfortunately neither has a copy-constructor nor a public static copy method. class A { private int i; // <- private, cant access String x; // <- even worse: cant access unless in same pkg! /* … other stuff, ctor, etc. … */ public A clone() { A a = new A(); a.i = i; a.x = x; return x; } } Guess further, there is some function that returns an object of that class: public static A someFn(x,y,z); Now the problem: I want to derive from that class to add some functionality. Unfortunately, i neither have a sizeof in java nor a cc or static copy method. So when i do a class B extends A { protected w; public B clone() { /* as usual */ } } then i can clone my B and get a new one, but how can i convert the returned A from someFn() into a B. Is there anyway to do the opposite of slicing in java? if i clone it, it's still an A, and i cant copy it field by field. This is all simple in c++, but how to do this in Java?

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  • Do COM Dll References Require Manual Disposal? If so, How?

    - by Drew
    I have written some code in VB that verifies that a particular port in the Windows Firewall is open, and opens one otherwise. The code uses references to three COM DLLs. I wrote a WindowsFirewall class, which Imports the primary namespace defined by the DLLs. Within members of the WindowsFirewall class I construct some of the types defined by the DLLs referenced. The following code isn't the entire class, but demonstrates what I am doing. Imports NetFwTypeLib Public Class WindowsFirewall Public Shared Function IsFirewallEnabled as Boolean Dim icfMgr As INetFwMgr icfMgr = CType(System.Activator.CreateInstance(Type.GetTypeFromProgID("HNetCfg.FwMgr")), INetFwMgr) Dim profile As INetFwProfile profile = icfMgr.LocalPolicy.CurrentProfile Dim fIsFirewallEnabled as Boolean fIsFirewallEnabled = profile.FirewallEnabled return fIsFirewallEnabled End Function End Class I do not reference COM DLLs very often. I have read that unmanaged code may not be cleaned up by the garbage collector and I would like to know how to make sure that I have not introduced any memory leaks. Please tell me (a) if I have introduced a memory leak, and (b) how I may clean it up. (My theory is that the icfMgr and profile objects do allocate memory that remains unreleased until after the application closes. I am hopeful that setting their references equal to nothing will mark them for garbage collection, since I can find no other way to dispose of them. Neither one implements IDisposable, and neither contains a Finalize method. I suspect they may not even be relevant here, and that both of those methods of releasing memory only apply to .Net types.)

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  • JPA - Entity design problem

    - by Yatendra Goel
    I am developing a Java Desktop Application and using JPA for persistence. I have a problem mentioned below: I have two entities: Country City Country has the following attribute: CountryName (PK) City has the following attribute: CityName Now as there can be two cities with same name in two different countries, the primaryKey for City table in the datbase is a composite primary key composed of CityName and CountryName. Now my question is How to implement the primary key of the City as an Entity in Java @Entity public class Country implements Serializable { private String countryName; @Id public String getCountryName() { return this.countryName; } } @Entity public class City implements Serializable { private CityPK cityPK; private Country country; @EmbeddedId public CityPK getCityPK() { return this.cityPK; } } @Embeddable public class CityPK implements Serializable { public String cityName; public String countryName; } Now as we know that the relationship from Country to City is OneToMany and to show this relationship in the above code, I have added a country variable in City class. But then we have duplicate data(countryName) stored in two places in the City class: one in the country object and other in the cityPK object. But on the other hand, both are necessary: countryName in cityPK object is necessary because we implement composite primary keys in this way. countryName in country object is necessary because it is the standard way of showing relashionship between objects. How to get around this problem?

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  • Python and the self parameter

    - by Svend
    I'm having some issues with the self parameter, and some seemingly inconsistent behavior in Python is annoying me, so I figure I better ask some people in the know. I have a class, Foo. This class will have a bunch of methods, m1, through mN. For some of these, I will use a standard definition, like in the case of m1 below. But for others, it's more convinient to just assign the method name directly, like I've done with m2 and m3. import os def myfun(x, y): return x + y class Foo(): def m1(self, y, z): return y + z + 42 m2 = os.access m3 = myfun f = Foo() print f.m1(1, 2) print f.m2("/", os.R_OK) print f.m3(3, 4) Now, I know that os.access does not take a self parameter (seemingly). And it still has no issues with this type of assignment. However, I cannot do the same for my own modules (imagine myfun defined off in mymodule.myfun). Running the above code yields the following output: 3 True Traceback (most recent call last): File "foo.py", line 16, in <module> print f.m3(3, 4) TypeError: myfun() takes exactly 2 arguments (3 given) The problem is that, due to the framework I work in, I cannot avoid having a class Foo at least. But I'd like to avoid having my mymodule stuff in a dummy class. In order to do this, I need to do something ala def m3(self,a1, a2): return mymodule.myfun(a1,a2) Which is hugely redundant when you have like 20 of them. So, the question is, either how do I do this in a totally different and obviously much smarter way, or how can I make my own modules behave like the built-in ones, so it does not complain about receiving 1 argument too many.

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  • Ninject giving NullReferenceException

    - by Iceman
    I'm using asp.net MVC 2 and Ninject 2. The setup is very simple. Controller calls service that calls repository. In my controller I use inject to instantiate the service classes with no problem. But the service classes don't instantiate the repositories, giving me NullReferenceException. public class BaseController : Controller { [Inject] public IRoundService roundService { get; set; } } This works. But then this does not... public class BaseService { [Inject] public IRoundRepository roundRepository { get; set; } } Giving a NullReferenceException, when I try to use the roundRepository in my RoundService class. IList<Round> rounds = roundRepository.GetRounds( ); Module classes... public class ServiceModule : NinjectModule { public override void Load( ) { Bind( ).To( ).InRequestScope( ); } } public class RepositoryModule : NinjectModule { public override void Load( ) { Bind<IRoundRepository>( ).To<RoundRepository>( ).InRequestScope( ); } } In global.axax.cs protected override IKernel CreateKernel( ) { return new StandardKernel( new ServiceModule( ), new RepositoryModule( ) ); }

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  • How can I find all attributes with single quotes in a Sublime Text 2 document and replace with double quotes?

    - by Brandon Durham
    I'm feeling particularly nit-picky today. I'm working in some HTML docs that have single quotes around all attribute values through the docs, like this: <div class='classone classtwo'> I'd love to be able to do a find-and-replace in each doc and replace with double quotes, like this: <div class="classone classtwo"> Many elements in the document will have multiple attributes: <div class='classone classtwo' data-scripts='lazyload'> And some will have the correct double quotes: <div class='classone classtwo' data-scripts="lazyload"> What's the best way to replace all single quotes wrapping values with double?

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  • How does Perl's lib pragma work?

    - by Tyug
    I use use lib "./DIR" to grab a library from a folder elsewhere. However, it doesn't seem to work on my server, but it works fine on my local desktop. Any particular reasons? And one more question, does use lib get propagated within several modules? Two situations: Say I make a base class that requires a few libraries, but I know that it needs to be extended and the extended class will need to use another library. Can I put the use lib command in the base class? or will I need to put it in every extending class? Finally, can I just have a use package where package contains a bunch of use lib, will it propagate the use lib statements over to my current module? <-- I don't think so, but asking anyways

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  • How to accept localized date format (e.g dd/mm/yy) in a DateField on an admin form ?

    - by tomjerry
    Is it possible to customize a django application to have accept localized date format (e.g dd/mm/yy) in a DateField on an admin form ? I have a model class : class MyModel(models.Model): date = models.DateField("Date") And associated admin class class MyModelAdmin(admin.ModelAdmin): pass On django administration interface, I would like to be able to input a date in following format : dd/mm/yyyy. However, the date field in the admin form expects yyyy-mm-dd. How can I customize things ? Nota bene : I have already specified my custom language code (fr-FR) in settings.py, but it seems to have no effect on this date input matter. Thanks in advance for your answer

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  • php OOP function declarations

    - by kris
    I'm a big fan of OOP in php, but i feel like defining class methods gets disorganized so fast. I have a pretty good background in OOP in C++, and i am pretty comfortable with how it is handled there, and am curious if there are ways to do it similarly in php. To be more specific, here is what i mean. I like how in C++ you can define a class header (myclass.h) and then define the actual details of the functions in the implementation file (myclass.cc). Ive found that this can easily be replicated using interfaces in php, but i havent found a good solution for the following: I like to organize my code in C++ in different files based on how they are accessed, so for example, public methods that can be called outside of the class would be in 1 place, and private methods would be organized somewhere else - this is personal preference. Ive tried to define class methods in php like: private function MyPHPClass::myFunction(){ } when the definition isnt directly inside the class block( { } ), but i havent had any success doing this. Ive been through all of the pages on php.net, but couldnt find anything like this. Im assuming that there is no support for something like this, but thought i would ask anyway. thanks

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  • Is this a bug or something I am doing wrong?

    - by Brian Gideon
    I cannot imagine how this is anything other than a bug, but since I do not currently have a login for the MS Connect website I will ask here first. I have Visual Studio 2008 SP 1 with all post SP1 hotfixes I could find relating to the crash installed. Can you reproduce the following crash? 1) Create a new "WPF Application" project using VB as the language (though I suspect it will happen in C# as well). 2) Enter the following code in the Window1.xaml.vb file. Friend MustInherit Class A End Class Friend MustInherit Class A(Of T) Inherits A End Class 3) Add a namespace declaration the Window1.xaml file so that it looks like the following. <Window x:Class="Window1" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:WpfApplication1" Title="Window1" Height="300" Width="300"> <Grid> </Grid> </Window> 4) Now attempt to edit the xaml file by opening a new xml tag via the < character. 5) CRASH! Edit: Microsoft has confirmed this bug. The issue still exists in VS2010 beta 2, but will be fixed in the next release.

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  • Wrapper Classes for Backward compatibility in Java

    - by Casebash
    There is an interesting article here on maintaing backwards compatibility for Java. In the wrapper class section, I can't actually understand what the wrapper class accomplishes. In the following code from MyApp, WrapNewClass.checkAvailable() could be replaced by Class.forName("NewClass"). static { try { WrapNewClass.checkAvailable(); mNewClassAvailable = true; } catch (Throwable ex) { mNewClassAvailable = false; } } Consider when NewClass is unavailable. In the code where we use the wrapper (see below), all we have done is replace a class that doesn't exist, with one that exists, but which can't be compiled as it uses a class that doesn't exist. public void diddle() { if (mNewClassAvailable) { WrapNewClass.setGlobalDiv(4); WrapNewClass wnc = new WrapNewClass(40); System.out.println("newer API is available - " + wnc.doStuff(10)); }else { System.out.println("newer API not available"); } } Can anyone explain why this makes a difference? I assume it has something to do with how Java compiles code - which I don't know much about.

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  • What does the C# compiler mean when it prints "an explicit conversion exists"?

    - by Wim Coenen
    If I make an empty test class: public class Foo { } And I try to compile code with this statement: Foo foo = "test"; Then I get this error as expected: Cannot implicitly convert type 'string' to 'ConsoleApplication1.Foo' However, if I change the declaration of Foo from class to interface, the error changes to this (emphasis mine): Cannot implicitly convert type 'string' to 'ConsoleApplication1.Foo'. An explicit conversion exists (are you missing a cast?) What is this "explicit conversion" which is supposed to exist?

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  • What makes this "declarator invalid"? C++

    - by nieldw
    I have Vertex template in vertex.h. From my graph.h: 20 template<class edgeDecor, class vertexDecor, bool dir> 21 class Vertex; which I use in my Graph template. I've used the Vertex template successfully throughout my Graph, return pointers to Vertices, etc. Now for the first time I am trying to declare and instantiate a Vertex object, and gcc is telling me that my 'declarator' is 'invalid'. How can this be? 81 template<class edgeDecor, class vertexDecor, bool dir> 82 Graph<edgeDecor,int,dir> Graph<edgeDecor,vertexDecor,dir>::Dijkstra(vertex s, bool print = false) const 83 { 84 /* Construct new Graph with apropriate decorators */ 85 Graph<edgeDecor,int,dir> span = new Graph<edgeDecor,int,dir>(); 86 span.E.reserve(this->E.size()); 87 88 typename Vertex<edgeDecor,int,dir> v = new Vertex(INT_MAX); 89 span.V = new vector<Vertex<edgeDecor,int,dir> >(this->V.size,v); 90 }; And gcc is saying: graph.h: In member function ‘Graph<edgeDecor, int, dir> Graph<edgeDecor, vertexDecor, dir>::Dijkstra(Vertex<edgeDecor, vertexDecor, dir>, bool) const’: graph.h:88: error: invalid declarator before ‘v’ graph.h:89: error: ‘v’ was not declared in this scope I know this is probably another noob question, but I'll appreciate any help.

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  • [iPhone]Objective C, objects which do not conform to NSCoding. How to write them to a file.

    - by Noah
    Hi, I am using an Objective c class, a subclass of NSObject. This class cannot be modified. I have an instance of this class that I wish to write to a file which can be retrieved and later reinstate. The object does not conform to NSCoding. To sum up, I need to save an instance of a class to a file which can be retrieved later, without using any of the NSCoding methods such as NSKeyedArchiving encodeWithCoder ... Using them returns this... NSInvalidArgumentException ...encodeWithCoder:] unrecognised selector sent to instance... Is there any other way I can store this object for later use Thank you

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  • Is it possible to convert this asp to asp.net?

    - by Phil
    I have been tasked with sifting through the worst classic asp spaghetti i've ever come across. The script runs a series of recordsets in sequence, getting 1 record at a time. As the record is built it takes the id and passes it to the next loop, which gets data, and passes on the id to the next loop. It then continues in this manner and builds an unordered list, kicking out the required html as it goes. Here are my efforts so far: have a class delivering data via sqldatareaders and output these to nested repeaters (this failed due to not being able to loop and get the id) Have a datatable populated with all the required data, then datatable.select to filter it out. have 4 datareaders looping and building the ul arraylists (I couldnt get the id's to match up) Please can you suggest the best method (with a bit of sample code if possible) to go about doing this conversion? Here is the code (sorry its long / horrible / spaghetti!!!) <% set RSMenuLevel0 = conn.execute("select id, DepartmentID, GroupingID, Heading, OrderID, Publish, moduleid, url, urltarget " &_ "from Grouping where (DepartmentID = 0 and GroupingID = 0 and Publish <> 0) order by OrderID") %> <% if session("JavaScriptEnabled") = "False" Then %> <% while not RSMenuLevel0.EOF if RSMenuLevel0("Publish") <> 0 then Menu0heading = RSMenuLevel0("Heading") Menu0id = RSMenuLevel0("id") %> <%if RSMenuLevel0("url") > "" and RSMenuLevel0("moduleid") = 0 then%> &nbsp;<a href="http://<%=RSMenuLevel0("url")%>" target="<%=RSMenuLevel0("urltarget")%>"><%=Menu0heading%></a> <%else%> &nbsp;<a href="/default.asp?id=<%=Menu0id%>"><%=Menu0heading%></a> <%end if%> <% end if RSMenuLevel0.MoveNext wend %> <% else %> <ul id="Menu1" class="MM"> <%if home <> 1 then%> <!-- <li><a href="/default.asp"><span class="item">Home</span></a> --> <%end if%> <% numone=0 while not RSMenuLevel0.EOF ' numone = numone + 1 Menu0heading = RSMenuLevel0("Heading") 'itemID = lcase(replace(Menu0heading," ","")) Menu0id = RSMenuLevel0("id") if RSMenuLevel0("url") > "" and RSMenuLevel0("moduleid") = 0 then url = RSMenuLevel0("url") if instr(url,"file:///") > 0 then %> <li><a href="<%=RSMenuLevel0("url")%>" target="<%=RSMenuLevel0("urltarget")%>" <%if numone=1 then%>class="CURRENT"<%end if%>><span class="item"><%=Menu0heading%></span></a> <%else%> <li><a href="http://<%=RSMenuLevel0("url")%>" target="<%=RSMenuLevel0("urltarget")%>" <%if numone=1 then%>class="CURRENT"<%end if%>><span class="item"><%=Menu0heading%></span></a> <%end if%> <%else%> <li><a href="/default.asp?id=<%=RSMenuLevel0("id")%>" <%if numone=1 then%>class="CURRENT"<%end if%>><span class="item"><%=Menu0heading%></span></a> <%end if%> <% set RSMenuLevel1 = conn.execute("select id, DepartmentID, GroupingID, Heading, OrderID, Publish, moduleid, url, urltarget " &_ "from Grouping where (DepartmentID = 0 and GroupingID = " & Menu0id & " and Publish <> 0) order by OrderID") if not RSMenuLevel1.EOF then %> <ul> <% while not RSMenuLevel1.EOF Menu1heading = RSMenuLevel1("Heading") Menu1id = RSMenuLevel1("id") if RSMenuLevel1("url") > "" and RSMenuLevel1("moduleid") = 0 then url = RSMenuLevel1("url") if instr(url,"file:///") > 0 then %> <li><a href="<%=RSMenuLevel1("url")%>" target="<%=RSMenuLevel1("urltarget")%>"><%=Menu1heading%></a> <%else%> <li><a href="http://<%=RSMenuLevel1("url")%>" target="<%=RSMenuLevel1("urltarget")%>"><%=Menu1heading%></a> <%end if%> <%else%> <li><a href="/default.asp?id=<%=RSMenuLevel1("id")%>"><%=Menu1heading%></a> <%end if%> <% set RSMenuLevel2 = conn.execute("select id, DepartmentID, GroupingID, Heading, OrderID, Publish, moduleid, url, urltarget " &_ "from Grouping where (DepartmentID = 0 and GroupingID = " & Menu1id & " and Publish <> 0) order by OrderID") if not RSMenuLevel2.EOF then %> <ul> <% while not RSMenuLevel2.EOF Menu2heading = RSMenuLevel2("Heading") Menu2id = RSMenuLevel2("id") if RSMenuLevel2("url") > "" and RSMenuLevel2("moduleid") = 0 then %> <li><a href="http://<%=RSMenuLevel2("url")%>" target="<%=RSMenuLevel2("urltarget")%>"><%=Menu2heading%></a> <%else%> <li><a href="/default.asp?id=<%=RSMenuLevel2("id")%>"><%=Menu2heading%></a> <%end if%> <% set RSMenuLevel3 = conn.execute("select id, DepartmentID, GroupingID, Heading, OrderID, Publish, moduleid, url, urltarget " &_ "from Grouping where (DepartmentID = 0 and GroupingID = " & Menu2id & " and Publish <> 0) order by OrderID") if not RSMenuLevel3.EOF then %> <ul> <% while not RSMenuLevel3.EOF Menu3heading = RSMenuLevel3("Heading") Menu3id = RSMenuLevel3("id") if RSMenuLevel3("url") > "" and RSMenuLevel3("moduleid") = 0 then %> <li><a href="http://<%=RSMenuLevel3("url")%>" target="<%=RSMenuLevel3("urltarget")%>"><%=Menu3heading%></a></li> <%else%> <li><a href="/default.asp?id=<%=RSMenuLevel3("id")%>"><%=Menu3heading%></a></li> <%end if%> <% RSMenuLevel3.MoveNext wend %> </ul> <% end if RSMenuLevel2.MoveNext %> </li> <% wend %> </ul> <% end if RSMenuLevel1.MoveNext %> </li> <% wend %> </ul> <% end if RSMenuLevel0.MoveNext %> </li> <% wend %> </ul> <% end if %>

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  • Returning a C++ reference in a const member functionasses

    - by Chris Kaminski
    A have a class hierarchy that looks somethign like this: class AbstractDataType { public: virtual int getInfo() = 0; }; class DataType: public AbstractDataType { public: virtual int getInfo() { }; } class Accessor { DataType data; public: const AbstractDataType& getData() const { return(data); } } Well, GCC 4.4 reports: In member function ‘const AbstractDataType& Accessor::getData() const’: error: invalid initialization of reference of type ‘const AbstractDataType&’ from expression of type ‘const DataType’ Where am I going wrong - is this a case where I MUST use a pointer?

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  • python 'self' explained

    - by richzilla
    What is the purpose of the 'self' word in python. I understand it refers to the specific object created from that class, but i cant see why it explicitly needs to be added to very function as a parameter. To illustrate, in ruby, i could do this: class myClass def myFunc(name) @name = name end end Which i understand, quite easily, However in python i need to include self: class myClass: def myFunc(self, name): self.name = name Can anyone talk me through this? Any help would be appreciated.

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  • jQuery Prepend an Image

    - by Tom
    Hi Guys, I am trying to add a prepend of an image and then define it's attributes. Little confused as how to do this - currently I have the following but it's not working. The HTML is <div id="testID" class="test1"> <div id="testID2" class="test2" ></div> </div> And the JS is jQuery("#testID2").prepend('<img />').attr({ src: 'some src.gif', alt: '', height: '60' }); I am hoping to achieve <div id="testID" class="test1"> <div id="testID2" class="test2" > <img src='some src.gif' alt='' height='60' /> </div> </div> Any Ideas?

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  • Adding classes to all form widgets in symfony

    - by rlahay
    Hi everyone, I am trying to find a better way to assign classes to form elements in symfony. Currently, I can't seem to get away from assigning each one manually. ie: $this->widgetSchema['title']->setAttribute("class","fieldInput"); $this->widgetSchema['tag_line']->setAttribute("class","fieldInput"); $this->widgetSchema['description']->setAttribute("class","fieldInput"); // etc Things I tried without success 1) looping through $this-widgetSchema, treating it as an array and setting attributes to each key 2) $this-widgetSchema-setAttribute() but this only applied the class to the label that was generated, not the form element There must be a way to hit all the fields without specifically directing them? Can anyone point me in the right direction?

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