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  • Is the F# language reference documentation available in an offline format (PDF, CHM)?

    - by stakx
    I've found several posts on hubFS of people asking if there is, or will be, offline documentation for F#. These posts haven't been answered. So I want to give it a shot and ask the same question here on SO. Where I've looked for offline documentation so far: The April 2010 CTP release of Visual F# (version 2.0) is available for VS 2008, but it doesn't come without an offline help. There's a question on SO about offline documentation for various programming languages, but F# isn't mentioned there at the time of this writing. There is of course Microsoft's F# language reference documentation (available on MSDN), which could be downloaded for offline browsing using e.g. wget. Question: Does anyone know whether any "official" offline documentation is on the way, anytime soon? (And related to this, albeit this probably can't be answered objectively: Would it be reasonable to expect that F# likely won't undergo ECMA or ISO standardization, ie. there likely won't be a standards document describing the language?)

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  • Ruby implementation of conversion between Latitude/Longitude and OS National Grid Reference point?

    - by Harry Wood
    For converting between Latitude/Longitude and UK's Ordnance Survey National Grid eastings and northings, this seems to be the most popular explanation and reference implementation in JavaScript: http://www.movable-type.co.uk/scripts/latlong-gridref.html The web is littered with other implementations in different languages. Making the conversion via PostGIS queries is another alternative. ...but did anyone implement this maths in ruby? OSGridToLatLong is the direction I'm looking for just at this moment, but I would have thought a library for converting in both directions must surely be available in a gem somewhere. I'm just not searching for the right thing.

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  • How to attach boost::shared_ptr (or another smart pointer) to reference counter of object's parent?

    - by Checkers
    I remember encountering this concept before, but can't find it in Google now. If I have an object of type A, which directly embeds an object of type B: class A { B b; }; How can I have a smart pointer to B, e. g. boost::shared_ptr<B>, but use reference count of A? Assume an instance of A itself is heap-allocated I can safely get its shared count using, say, enable_shared_from_this.

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  • Are memory barriers necessary for atomic reference counting shared immutable data?

    - by Dietrich Epp
    I have some immutable data structures that I would like to manage using reference counts, sharing them across threads on an SMP system. Here's what the release code looks like: void avocado_release(struct avocado *p) { if (atomic_dec(p->refcount) == 0) { free(p->pit); free(p->juicy_innards); free(p); } } Does atomic_dec need a memory barrier in it? If so, what kind of memory barrier? Additional notes: The application must run on PowerPC and x86, so any processor-specific information is welcomed. I already know about the GCC atomic builtins. As for immutability, the refcount is the only field that changes over the duration of the object.

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  • How do I reference members of a single object passed to the View?

    - by Juxtaposed
    I'm new to MVC2 in ASP.NET/C#, so please forgive me if I misunderstand something. I have code similar to this in my Controller: var singleInstance = new Person("John"); ViewData["myInstance"] = singleInstance; return View(); So in my view, Index.aspx, I want to be able to reference members in that object. For example, Person has a member called Name, which is set in the constructor. In the view I want to get Person.Name from what is stored in the ViewData object. Ex.: <%= ViewData["myInstance"].name %> That doesn't work. The only real workaround I've found is to do something like this: <% var thePerson = ViewData["myInstance"]; print (or whatever the method is) thePerson.Name; %> Any help would be much appreciated... This was so much easier in PHP/Zend Framework... sigh

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  • Visual studio do not add my Component (from a dll) to the toolbox even if I reference it

    - by Fire-Dragon-DoL
    As stated in the title, I copied my dll in visual studio project, set it to "content" and "copy always". Added a reference to this dll and set it to "copy locally". I successfully managed to instance my component to a form through code but it doesn't appear in the toolbox, really boring. How can I solve this issue? If I link directly the dll project to this project it works, but now I'm treating the dll as "external" so it's not part of the same solution of the dll project. Thanks for any help

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  • Is there a way to reference a certain class/interface/... by enclosing it with its namespace rather than a using directive "using namespace_name" ?!

    - by Ahmed
    Is there a way to reference a certain class/interface/... by enclosing it with its namespace rather than a using directive "using namespace_name" ?! As, I'm working on a website, which uses SAP .NET connector. I already added a reference for connector ddl, and while referencing its namespace "using namespace_name", or set class namespace to another one rather than connector namespace, I got error regarding connector classes with that error message "The type or namespace couldn't be found, are you missing a using directive or an assembly reference?". But while changing namespace name to connector namespace, everything is going well?! // Set namespace to be IDestinationConfiguration interface namespace. namespace SAP.Middleware.Connector { public class ConnectorConfiguration : IDestinationConfiguration { } } So, connector types forced me to set namespace of class to their namespace! Is this possible? If so, how?

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  • Should I use a modified singleton design pattern that only allows one reference to its instance?

    - by Graham
    Hi, I have a class that would normally just generate factory objects, however this class should only used once throughout the program in once specifix place. What is the best design pattern to use in this instance? I throught that having a modified singleton design which only allows one reference to instance throughout the program would be the correct way to go. So only the first call to getInstance() returns the factory library. Is this a good or bad idea? Have I missed out another fundermental design pattern for solving this problem? Thanks for your help.

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  • How do you pull the URL for an ASP.NET web reference from a configuration file in Visual Studio 2008

    - by Ian Robinson
    I have a web reference for our report server embedded in our application. The server that the reports live on could change though, and I'd like to be able to change it "on the fly" if necessary. I know I've done this before, but can't seem to remember how. Thanks for your help. update - I've manually driven around this for the time being. It's not a big deal to set the URL in the code, but I'd like to figure out what the "proper" way of doing this in VS 2008 is. Could anyone provide any further insights? Thanks!

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  • What if I made an explicit reference to 'this' for use inside an inner class?

    - by badp
    So far, I've used this approach to access this from the scope of an inner class: class FooManagementWindow extends JFrame { JButton rejectFoo; //... void getFooAcceptingPanel(){ //... final FooManagementWindow referenceToThis = this; rejectFoo = new JButton("Reject"); rejectFoo.addEventListener(new EventListener() { @Override public void actionPerformed(ActionEvent arg) { referenceToThis.setEnabled(false); //this requires a network call //... referenceToThis.setEnabled(true); //the user may resume his work } }); //... } } However, I just learned that instead of declaring referenceToThis, a direct reference is kept for me as: FooManagementWindow.this I have no reason to think my less standard approach may lead to errors or weird corner cases. Or are there?

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  • Is it a good practice to create a reference to application context and use it anywhere?

    - by kknight
    I have to use context in many places of my code such as database operations, preference operations, etc. I don't want to pass in context for every method. Is it a good practice to create a reference to application context at the main Activity and use it anywhere such as database operations? So, I don't need some many context in method parameters, and the code can avoid position memory leak due to use of Activity Context. public class MainActivity extends Activity { public static Context s_appContext; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); s_appContext = this.getApplicationContext();

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  • How to pass and set a CGFloat by reference?

    - by mystify
    I want to make an method which takes an CGFloat by reference. Could I do something like this? - (void)doStuff:(CGFloat*)floatPointer I guess this must look different than other object pointers which have two of those stars. Also I'm not sure if I must do something like: - (void)doStuff:(const CGFloat*)floatPointer And of course, no idea how to assign an CGFloat value to that floatPointer. Maybe &floatPointer = 5.0f; ? Could someone give some examples and explain these? Would be great!

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  • Inheritance: possible to change base reference to something else?

    - by fred
    For example I have two classes, Base and Derived as shown below: class Base { public string Name { get; set; } public Base() { } } class Derived : Base { public Derived(Base b) { base = b; // doesn't compile, but is there any way to do something similar? } } So that they behave like this: Base b = new Base(); b.Name = "Bob"; Derived d = new Derived(b); d.Name = "John"; // b.Name is now "John" also Is this possible? I guess one way would be to keep the Base b reference in Derived and override Derived.Name to point to b.Name? Is there an easier way though, for example if I have like 50 properties to override? class Derived : Base { Base b; public override string Name { get { return b.Name; } set { b.Name = value; } } public Derived(Base b) { this.b = b; } }

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  • Is it possible to use a back reference to specify the number of replications in a regular expression

    - by user307894
    Is it possible to use a back reference to specify the number of replications in a regular expression? foo= 'ADCKAL+2AG.+2AG.+2AG.+2AGGG+.+G+3AGGa4.' The substrings that start with '+[0-9]' followed by '[A-z]{n}.' need to be replaced with simply '+' where the variable n is the digit from earlier in the substring. Can that n be back referenced? For example (doesn't work) '+([0-9])[A-z]{/1}.' is the pattern I want replaced with "+" (that last dot can be any character and represents a quality score) so that foo should come out to ADCKAL++++G.G+. foo = 'ADCKAL+2AG.+2AG.+2AG.+2AGGG^+.+G+3AGGa4.' indelpatt = re.compile('\+([0-9])') while indelpatt.search(foo): indelsize=int(indelpatt.search(foo).group(1)) new_regex = '\+%s[ACGTNacgtn]{%s}.' % (indelsize,indelsize) newpatt=re.compile(new_regex) foo = newpatt.sub("+", foo) I'm probably missing an easier way to parse the string.

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  • C++0x: how to get variadic template parameters without reference?

    - by Sydius
    Given the following contrived (and yes, terrible) example: template<typename... Args> void something(Args... args) { std::tuple<Args...> tuple; // not initializing for sake of example std::get<0>(tuple) = 5; } It works if you call it like so: int x = 10; something<int>(x); However, it does not work if you call it like this: int x = 10; something<int&>(x); Because of the assignment to 5. Assuming that I cannot, for whatever reason, initialize the tuple when it is defined, how might I get this to work when specifying the type as a reference? Specifically, I would like the tuple to be std::tuple<int> even when Args... is int&.

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  • How do I reference a pointer from a different class?

    - by Justagruvn
    First off, I despise singletons with a passion. Though I should probably be trying to use one, I just don't want to. I want to create a data class (that is instantiated only once by a view controller on loading), and then using a different class, message the crap out of that data instance until it is brimming with so much data, it smiles. So, how do I do that? I made a pointer to the instance of the data class when I instantiated it. I'm now over in a separate view controller, action occurs, and I want to update the initial data object. I think I need to reference that object by way of pointer, but I have no idea how to do that. Yes, I've set properties and getters and setters, which seem to work, but only in the initial view controller class. Peace Love applesauce.

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  • How to reference/link another project in grails workspace without using jar files?

    - by Ivan Alagenchev
    I have a Grails website that references a java core application. I have been successful in adding a .jar dependency to that project; however the java project is in the same workspace as my grails project and I would ultimately like to reference that project directly. I don't want to deal with the added step of creating a new jar file every time that there is a modification to the java project, cleaning and updating my dependencies. I added the java project to my grails' project "Java Build Path" and at first everything seemed to work fine, but when I run grailscompile, the compiler fails to resolve all imports that point to the java project. I am using Spring Source Toolsuite as my IDE.

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  • How do i get (is it possible to) a reference to the class that creates an instance of another class.

    - by Cadde
    Odd situation... I need to create a new instance of a class that needs a member of the calling class. But i can't pass a reference to the calling class through the constructor. The solution i am looking for is something like this: Public Class ChildClass Public Sub New(args) _MyMember = GetMemberFromCallingClass() ... ... End Sub End Class I want this to work without having to manually pass any references or variables from the calling class to the new instance of ChildClass. Is this possible and if so, what should i look at to make this part of my code.

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  • Checking for a session variable... returns (Object reference not set to an instance of an object.)

    - by Chocol8
    In the Session_Start i have Sub Session_Start(ByVal sender As Object, ByVal e As EventArgs) Session("login") = False End Sub and in a custom .aspx page i included the following... Public ReadOnly Property GetLoginState() As Boolean Get If Current.Session("login") Is Nothing Then Current.Session("login") = False End If Return Current.Session("login") End Get End Property Why i am getting error the error Object reference not set to an instance of an object. at line If Current.Session("login") Is Nothing Then while checking for the login state as follows? If GetLogin = False Then 'Do something End if I mean i have already created the instance on the Session_Start... Haven't i? What am i doing wrong here?

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  • How Do I Reference An Element By Name With [] Brackets In It?

    - by user384030
    How do you reference a element in jquery BY NAME that has the [] in it. <select name="values[]" multiple="true"> <option value="1">1</option> <option value="2">2</option> <option value="2">2</option> </select> <script type="text/javascript"> $('[name=values[]]'); </script> this should grab the element, but it does not work, I believe the [] in the name is messing it up, escaping it doesn't seem to work either. I can't figure out what I'm doing wrong

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  • C#/.NET Little Pitfalls: The Dangers of Casting Boxed Values

    - by James Michael Hare
    Starting a new series to parallel the Little Wonders series.  In this series, I will examine some of the small pitfalls that can occasionally trip up developers. Introduction: Of Casts and Conversions What happens when we try to assign from an int and a double and vice-versa? 1: double pi = 3.14; 2: int theAnswer = 42; 3:  4: // implicit widening conversion, compiles! 5: double doubleAnswer = theAnswer; 6:  7: // implicit narrowing conversion, compiler error! 8: int intPi = pi; As you can see from the comments above, a conversion from a value type where there is no potential data loss is can be done with an implicit conversion.  However, when converting from one value type to another may result in a loss of data, you must make the conversion explicit so the compiler knows you accept this risk.  That is why the conversion from double to int will not compile with an implicit conversion, we can make the conversion explicit by adding a cast: 1: // explicit narrowing conversion using a cast, compiler 2: // succeeds, but results may have data loss: 3: int intPi = (int)pi; So for value types, the conversions (implicit and explicit) both convert the original value to a new value of the given type.  With widening and narrowing references, however, this is not the case.  Converting reference types is a bit different from converting value types.  First of all when you perform a widening or narrowing you don’t really convert the instance of the object, you just convert the reference itself to the wider or narrower reference type, but both the original and new reference type both refer back to the same object. Secondly, widening and narrowing for reference types refers the going down and up the class hierarchy instead of referring to precision as in value types.  That is, a narrowing conversion for a reference type means you are going down the class hierarchy (for example from Shape to Square) whereas a widening conversion means you are going up the class hierarchy (from Square to Shape).  1: var square = new Square(); 2:  3: // implicitly convers because all squares are shapes 4: // (that is, all subclasses can be referenced by a superclass reference) 5: Shape myShape = square; 6:  7: // implicit conversion not possible, not all shapes are squares! 8: // (that is, not all superclasses can be referenced by a subclass reference) 9: Square mySquare = (Square) myShape; So we had to cast the Shape back to Square because at that point the compiler has no way of knowing until runtime whether the Shape in question is truly a Square.  But, because the compiler knows that it’s possible for a Shape to be a Square, it will compile.  However, if the object referenced by myShape is not truly a Square at runtime, you will get an invalid cast exception. Of course, there are other forms of conversions as well such as user-specified conversions and helper class conversions which are beyond the scope of this post.  The main thing we want to focus on is this seemingly innocuous casting method of widening and narrowing conversions that we come to depend on every day and, in some cases, can bite us if we don’t fully understand what is going on!  The Pitfall: Conversions on Boxed Value Types Can Fail What if you saw the following code and – knowing nothing else – you were asked if it was legal or not, what would you think: 1: // assuming x is defined above this and this 2: // assignment is syntactically legal. 3: x = 3.14; 4:  5: // convert 3.14 to int. 6: int truncated = (int)x; You may think that since x is obviously a double (can’t be a float) because 3.14 is a double literal, but this is inaccurate.  Our x could also be dynamic and this would work as well, or there could be user-defined conversions in play.  But there is another, even simpler option that can often bite us: what if x is object? 1: object x; 2:  3: x = 3.14; 4:  5: int truncated = (int) x; On the surface, this seems fine.  We have a double and we place it into an object which can be done implicitly through boxing (no cast) because all types inherit from object.  Then we cast it to int.  This theoretically should be possible because we know we can explicitly convert a double to an int through a conversion process which involves truncation. But here’s the pitfall: when casting an object to another type, we are casting a reference type, not a value type!  This means that it will attempt to see at runtime if the value boxed and referred to by x is of type int or derived from type int.  Since it obviously isn’t (it’s a double after all) we get an invalid cast exception! Now, you may say this looks awfully contrived, but in truth we can run into this a lot if we’re not careful.  Consider using an IDataReader to read from a database, and then attempting to select a result row of a particular column type: 1: using (var connection = new SqlConnection("some connection string")) 2: using (var command = new SqlCommand("select * from employee", connection)) 3: using (var reader = command.ExecuteReader()) 4: { 5: while (reader.Read()) 6: { 7: // if the salary is not an int32 in the SQL database, this is an error! 8: // doesn't matter if short, long, double, float, reader [] returns object! 9: total += (int) reader["annual_salary"]; 10: } 11: } Notice that since the reader indexer returns object, if we attempt to convert using a cast to a type, we have to make darn sure we use the true, actual type or this will fail!  If the SQL database column is a double, float, short, etc this will fail at runtime with an invalid cast exception because it attempts to convert the object reference! So, how do you get around this?  There are two ways, you could first cast the object to its actual type (double), and then do a narrowing cast to on the value to int.  Or you could use a helper class like Convert which analyzes the actual run-time type and will perform a conversion as long as the type implements IConvertible. 1: object x; 2:  3: x = 3.14; 4:  5: // if you want to cast, must cast out of object to double, then 6: // cast convert. 7: int truncated = (int)(double) x; 8:  9: // or you can call a helper class like Convert which examines runtime 10: // type of the value being converted 11: int anotherTruncated = Convert.ToInt32(x); Summary You should always be careful when performing a conversion cast from values boxed in object that you are actually casting to the true type (or a sub-type). Since casting from object is a widening of the reference, be careful that you either know the exact, explicit type you expect to be held in the object, or instead avoid the cast and use a helper class to perform a safe conversion to the type you desire. Technorati Tags: C#,.NET,Pitfalls,Little Pitfalls,BlackRabbitCoder

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  • How to reference a Domain Controller out of the Local Network?

    - by Adrian
    We have multiple servers scattered over different hosting providers. For learning, experimenting and, ultimately, production purposes, I set one of them as a Domain Controller. That went well, most of our services are now authenticating via AD, which helps us a lot. What I want to do now is to simplify the authentication for the multiple servers, by making each of them look at the Domain Controller. This way, our Devs can log into (Remote Desktop) the multiple servers with the same credentials from AD. I know I have to configure each server to look at the Domain Controller. But when I try to add the Domain Controller to the Computer, it cannot find it, although the Domain Controller address is a valid, reachable internet sub-domain (as in "ad.ourcompany.com"). This is the detailed error message: Note: This information is intended for a network administrator. If you are not your network's administrator, notify the administrator that you received this information, which has been recorded in the file C:\Windows\debug\dcdiag.txt. The following error occurred when DNS was queried for the service location (SRV) resource record used to locate an Active Directory Domain Controller for domain ad.ourcompany.com: The error was: "DNS name does not exist." (error code 0x0000232B RCODE_NAME_ERROR) The query was for the SRV record for _ldap._tcp.dc._msdcs.ad.ourcompany.com Common causes of this error include the following: - The DNS SRV records required to locate a AD DC for the domain are not registered in DNS. These records are registered with a DNS server automatically when a AD DC is added to a domain. They are updated by the AD DC at set intervals. This computer is configured to use DNS servers with the following IP addresses: 109.188.207.9 109.188.207.10 - One or more of the following zones do not include delegation to its child zone: ad.ourcompany.com ourcompany.com com . (the root zone) For information about correcting this problem, click Help. What am I missing? I'm an experienced Dev, but a newbie Sysdamin experimenting with new stuff. Disclaimer All IP addresses and domains/subdomains were changed to preserve security. If by any chance you still can see private information, please let me know so that I can change it.

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  • The physical working paradigm of a signal passing on wire.

    - by smwikipedia
    Hi, This may be more a question of physics, so pardon me if there's any inconvenience. When I study computer networks, I often read something like this in order to represent a signal, we place some voltage on one end of the wire and the other end will detect the voltage and thus the signal. So I am wondering how a signal exactly passes through wire? Here's my current understanding based on my formal knowledge about electronics: First we need a close circuit to constrain/hold the electronic field. When we place a voltage at somewhere A of the circuit, electronic field will start to build up within the circuit medium, this process should be as fast as light speed. And as the electronic field is being built up, the electrons within the circuit medium are moved, and thus electronic current occurs, and once the electronic current is strong enough to be detected at somewhere else B on the complete circuit, then B knows about what has happend at A and thus communication between A and B is achieved. The above is only talking about the process of sending a single voltage through wire. If there's a bitstream and we need to send a series of voltages, I am not sure which of the following is true: The 2nd voltage should only be sent from A after the 1st voltage has been detected at B, the time interval is time needed to stimulate the electronic field in the medium and form a detectable electronic current at B. Several different voltages could be sent on wire one by one, different electronic current values will exists along the wire simutaneously and arrive at B successively. I hope I made myself clear and someone else has ever pondered this question. (I tag this question with network cause I don't know if there's a better option.) Thanks, Sam

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  • Can you reference an entire column in OpenOffice Calc (like A:A in Excel)?

    - by Andy
    I'd like to refer to an entire column, like you can in Excel by using A:A. I found a discussion on the openoffice.org forums which is a few years old, and suggests there is/was no neat way to do it. The options presented are Use A1:A65536. Use OFFSET($A$1;0;0;65536;1) as the previous range may get altered if you insert or remove rows. Use Data - Define Range... to name the column range (but which for me still just equates to $A$1:$A$1048576). These approaches seem over-complicated and still don't achieve my goal perfectly. Does anyone know of a way? Thanks, Andy

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