Search Results

Search found 99595 results on 3984 pages for 'file type'.

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

Page 12/3984 | < Previous Page | 8 9 10 11 12 13 14 15 16 17 18 19  | Next Page >

  • Unboxing to unknown type

    - by Robert
    I'm trying to figure out syntax that supports unboxing an integral type (short/int/long) to its intrinsic type, when the type itself is unknown. Here is a completely contrived example that demonstrates the concept: // Just a simple container that returns values as objects struct DataStruct { public short ShortVale; public int IntValue; public long LongValue; public object GetBoxedShortValue() { return LongValue; } public object GetBoxedIntValue() { return LongValue; } public object GetBoxedLongValue() { return LongValue; } } static void Main( string[] args ) { DataStruct data; // Initialize data - any value will do data.LongValue = data.IntValue = data.ShortVale = 42; DataStruct newData; // This works if you know the type you are expecting! newData.ShortVale = (short)data.GetBoxedShortValue(); newData.IntValue = (int)data.GetBoxedIntValue(); newData.LongValue = (long)data.GetBoxedLongValue(); // But what about when you don't know? newData.ShortVale = data.GetBoxedShortValue(); // error newData.IntValue = data.GetBoxedIntValue(); // error newData.LongValue = data.GetBoxedLongValue(); // error } In each case, the integral types are consistent, so there should be some form of syntax that says "the object contains a simple type of X, return that as X (even though I don't know what X is)". Because the objects ultimately come from the same source, there really can't be a mismatch (short != long). I apologize for the contrived example, it seemed like the best way to demonstrate the syntax. Thanks.

    Read the article

  • Explain ML type inference to a C++ programmer

    - by Tsubasa Gomamoto
    How does ML perform the type inference in the following function definition: let add a b = a + b Is it like C++ templates where no type-checking is performed until the point of template instantiation after which if the type supports the necessary operations, the function works or else a compilation error is thrown ? i.e. for example, the following function template template <typename NumType> NumType add(NumType a, NumType b) { return a + b; } will work for add<int>(23, 11); but won't work for add<ostream>(cout, fout); Is what I am guessing is correct or ML type inference works differently? PS: Sorry for my poor English; it's not my native language.

    Read the article

  • File Output using Gforth

    - by sheepez
    As a first project I have been writing a short program to render the Mandelbrot fractal. I have got to the point of trying to output my results to a file ( e.g. .bmp or .ppm ) and got stuck. I have not really found any examples of exactly what I am trying to do, but I have found two examples of code to copy from one file to another. The examples in the Gforth documentation ( Section 3.27 ) did not work for me ( winXP ) in fact they seemed to open and create files but not write to files properly. This is the Gforth documentation example that copies the contents of one file to another: 0 Value fd-in 0 Value fd-out : open-input ( addr u -- ) r/o open-file throw to fd-in ; : open-output ( addr u -- ) w/o create-file throw to fd-out ; s" foo.in" open-input s" foo.out" open-output : copy-file ( -- ) begin line-buffer max-line fd-in read-line throw while line-buffer swap fd-out write-line throw repeat ; I found this example ( http://rosettacode.org/wiki/File_IO#Forth ) which does work. The main problem is that I can't isolate the part that writes to a file and have it still work. The main confusion is that r doesn't seem to consume TOS as I might expect. : copy-file2 ( a1 n1 a2 n2 -- ) r/o open-file throw >r w/o create-file throw r> begin pad maxstring 2 pick read-file throw ?dup while pad swap 3 pick write-file throw repeat close-file throw close-file throw ; \ Invoke it like this: s" output.txt" s" input.txt" copy-file I would be very grateful if someone could explain exactly how the open, create read and write -file words actually work, as my investigation keeps resulting in somewhat bizarre stacks. Any clues as to why the Gforth examples do not work might help too. In summary, I want to output from Gforth to a file and so far have been thwarted. Can anyone offer any help? Thank you Vijay, I think that I understand the example that you gave. However when I try to use something like this ( which I think is similar ): 0 value test-file : write-test s" testfile.out" w/o create-file throw to test-file s" test text" test-file write-line ; I get ok but nothing is put into the file, have I made a mistake? It seems that the problem was due to not flushing the relevant buffers or explicitly closing the file. Adding something like test-file flush-file throw or test-file close-file throw between write-line and ; makes it work. Thanks again Vijay for helping.

    Read the article

  • 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"

    Read the article

  • Cannot initialize non-const reference from convertible type

    - by Julien L.
    Hi, I cannot initialize a non-const reference to type T1 from a convertible type T2. However, I can with a const reference. long l; const long long &const_ref = l; // fine long long &ref = l; // error: invalid initialization of reference of // type 'long long int&' from expression of type // 'long int' Most problems I encountered were related to r-values that cannot be assigned to a non-const reference. This is not the case here -- can someone explain? Thanks.

    Read the article

  • GHC.Generics and Type Families

    - by jberryman
    This is a question related to my module here, and is simplified a bit. It's also related to this previous question, in which I oversimplified my problem and didn't get the answer I was looking for. I hope this isn't too specific, and please change the title if you can think if a better one. Background My module uses a concurrent chan, split into a read side and write side. I use a special class with an associated type synonym to support polymorphic channel "joins": {-# LANGUAGE TypeFamilies #-} class Sources s where type Joined s newJoinedChan :: IO (s, Messages (Joined s)) -- NOT EXPORTED --output and input sides of channel: data Messages a -- NOT EXPORTED data Mailbox a instance Sources (Mailbox a) where type Joined (Mailbox a) = a newJoinedChan = undefined instance (Sources a, Sources b)=> Sources (a,b) where type Joined (a,b) = (Joined a, Joined b) newJoinedChan = undefined -- and so on for tuples of 3,4,5... The code above allows us to do this kind of thing: example = do (mb , msgsA) <- newJoinedChan ((mb1, mb2), msgsB) <- newJoinedChan --say that: msgsA, msgsB :: Messages (Int,Int) --and: mb :: Mailbox (Int,Int) -- mb1,mb2 :: Mailbox Int We have a recursive action called a Behavior that we can run on the messages we pull out of the "read" end of the channel: newtype Behavior a = Behavior (a -> IO (Behavior a)) runBehaviorOn :: Behavior a -> Messages a -> IO () -- NOT EXPORTED This would allow us to run a Behavior (Int,Int) on either of msgsA or msgsB, where in the second case both Ints in the tuple it receives actually came through separate Mailboxes. This is all tied together for the user in the exposed spawn function spawn :: (Sources s) => Behavior (Joined s) -> IO s ...which calls newJoinedChan and runBehaviorOn, and returns the input Sources. What I'd like to do I'd like users to be able to create a Behavior of arbitrary product type (not just tuples) , so for instance we could run a Behavior (Pair Int Int) on the example Messages above. I'd like to do this with GHC.Generics while still having a polymorphic Sources, but can't manage to make it work. spawn :: (Sources s, Generic (Joined s), Rep (Joined s) ~ ??) => Behavior (Joined s) -> IO s The parts of the above example that are actually exposed in the API are the fst of the newJoinedChan action, and Behaviors, so an acceptable solution can modify one or all of runBehaviorOn or the snd of newJoinedChan. I'll also be extending the API above to support sums (not implemented yet) like Behavior (Either a b) so I hoped GHC.Generics would work for me. Questions Is there a way I can extend the API above to support arbitrary Generic a=> Behavior a? If not using GHC's Generics, are there other ways I can get the API I want with minimal end-user pain (i.e. they just have to add a deriving clause to their type)?

    Read the article

  • php : get file content and store file in particular folder

    - by Sanjay
    hi , i am getting file content from file_get_content funtion in php. and want to store that file in particular folder. how could i store that file in particular folder. $image = file_get_contents('http://www.affiliatewindow.com/logos/1961/logo.gif'); i want to save this image in particular folder. any idea abt it?

    Read the article

  • Indirect load of type fails in PowerShell

    - by Dan
    When invoking [System.Configuration.ConfigurationManager]::GetSection("MySection") from within a PowerShell prompt, it throws an exception because the assembly containing the type represented by "MySection" in the app config is unable to be loaded. However, I have previously loaded the assembly containing that type, and I am even able to instantiate the type directly using 'new-object'. How is the ConfigurationManager resolving types such that the assemblies already loaded into the PowerShell app domain are not visible to it?

    Read the article

  • C#: Determine Type for (De-)Serialization

    - by dbemerlin
    Hi, i have a little problem implementing some serialization/deserialization logic. I have several classes that each take a different type of Request object, all implementing a common interface and inheriting from a default implementation: This is how i think it should be: Requests interface IRequest { public String Action {get;set;} } class DefaultRequest : IRequest { public String Action {get;set;} } class LoginRequest : DefaultRequest { public String User {get;set;} public String Pass {get;set;} } Handlers interface IHandler<T> { public Type GetRequestType(); public IResponse HandleRequest(IModel model, T request); } class DefaultHandler<T> : IHandler<T> // Used as fallback if the handler cannot be determined { public Type GetRequestType() { return /* ....... how to get the Type of T? ((new T()).GetType()) ? .......... */ } public IResponse HandleRequest(IModel model, T request) { /* ... */ } } class LoginHandler : DefaultHandler<LoginRequest> { public IResponse HandleRequest(IModel mode, LoginRequest request) { } } Calling class Controller { public ProcessRequest(String action, String serializedRequest) { IHandler handler = GetHandlerForAction(action); IRequest request = serializer.Deserialize<handler.GetRequestType()>(serializedRequest); handler(this.Model, request); } } Is what i think of even possible? My current Solution is that each handler gets the serialized String and is itself responsible for deserialization. This is not a good solution as it contains duplicate code, the beginning of each HandleRequest method looks the same (FooRequest request = Deserialize(serializedRequest); + try/catch and other Error Handling on failed deserialization). Embedding type information into the serialized Data is not possible and not intended. Thanks for any Hints.

    Read the article

  • Obtain container type from (its) iterator type in C++ (STL)

    - by KRao
    It is easy given a container to get the associated iterators, example: std::vector<double>::iterator i; //An iterator to a std::vector<double> I was wondering if it is possible, given an iterator type, to deduce the type of the "corresponding container" (here I am assuming that for each container there is one and only one (non-const) iterator). More precisely, I would like a template metafunction that works with all STL containers (without having to specialize it manually for each single container) such that, for example: ContainerOf< std::vector<double>::iterator >::type evaluates to std::vector<double> Is it possible? If not, why? Thank you in advance for any help!

    Read the article

  • How do I force specific permissions for new files/folders on Linux file server?

    - by humble_coder
    I'm having an issue with my install of Ubuntu 9.10 (file server) and its samba permissions. Logging in and reading works fine. However, creation of new directories by users restricts access for other users. For instance, if Bob (Windows user who maps the drive) creates a folder in the directory, Jane (Mac user that simply smb mounts) can read from it, but can't write to it -- and vice versa. I then must go CHMOD 777 the directory for everyone to be happy. I've tried editing the "create/directory mask", and "force" options in the smb.conf file but this doesn't seem to help. I'm about to resort to CRONTABing a recursive chmod routine, although I'm sure this isn't the fix. How do I get all new items to always be 777? Does anyone have any suggestions to fix this ever-occurring situation? Best

    Read the article

  • How to determine MIME Type set by htaccess in PHP

    - by Ed Marty
    I have a .htaccess file set up to define specific MIME types in directory root/a/b/, and all of the files are in the same directory. I have a php file that wants to serve those files, in directory root/c/, and needs to determine the content-type as defined by the .htaccess file. Is there any way to do this? PHP version is 5.1.6. mime_content_type returns text/plain, and I'd rather not try to parse the .htaccess file manually. I can move the file if necessary.

    Read the article

  • NoSQL as file meta database

    - by fga
    I am trying to implement a virtual file system structure in front of an object storage (Openstack). For availability reasons we initially chose Cassandra, however while designing file system data model, it looked like a tree structure similar to a relational model. Here is the dilemma for availability and partition tolerance we need NoSQL, but our data model is relational. The intended file system must be able to handle filtered search based on date, name etc. as fast as possible. So what path should i take? Stick to relational with some indexing mechanism backed by 3 rd tools like Apache Solr or dig deeper into NoSQL and find a suitable model and database satisfying the model? P.S: Currently from NoSQL Cassandra or MongoDB are choices proposed by my colleagues.

    Read the article

  • How to organize my site's file system properly?

    - by Wolfpack'08
    Doing some reading on Stack Overflow, I've found a lot of information suggesting that proper organization of a file system is crucial to a well-written web app. One of the key pieces of evidence is high-frequency references to "separation of concerns" in questions related to keeping programs organized. Now, I've found some information on organizing file systems (Filesystem Hierarchy Standard) from 2004. It raises only two concerns: first, the standard's a bit dated, so I believe it may be possible to do better given the changes in technology over the past 8 years; second, and most important, my application is very small compared to an entire Linux distro. I think that the file system should be organized very differently because of that. Here's what I'm looking at, currently: /scripts, /databases, /www -> /dev, /production -> login, router, admin pages, /sites -> content types, static pages /modules, /includes, /css, /media -> /module-specific-media

    Read the article

  • Dynamically loading type in Silverlight with Type.GetType()

    - by ondesertverge
    Trying to specify the assembly name like this: Type.GetType(string.Format("{0}.{1}, {0}", widget.Assembly, widget.Class)); Throws this: The requested assembly version conflicts with what is already bound in the app domain or specified in the manifest Trying it without the the assembly: Type.GetType(string.Format("{0}.{1}", widget.Assembly, widget.Class)); Returns null. I am looking for a way to instantiate a class using it's fully qualified name in Silverlight 4.0. Thanks.

    Read the article

  • Unable to cast object of type MyObject to type MyObject

    - by Robert W
    I have this scenario where a webservice method I'm consuming in C# returns a Business object, when calling the webservice method with the following code I get the exception "Unable to cast object of type ContactInfo to type ContactInfo" in the reference.cs class of the web reference Code: ContactInfo contactInfo = new ContactInfo(); Contact contact = new Contact(); contactInfo = contact.Load(this.ContactID.Value); Any help would be much appreciated.

    Read the article

  • Object of type "X" cannot be converted to object of type "X"

    - by Benjol
    (Can't believe this hasn't already been asked, but I can't find a dup) In Visual Studio with lots of projects, when I first open the solution, I sometimes get the warning Object of type "X" cannot be converted to object of type "X". Generally rebuilding seems to make it go away, but does anyone know what this is caused by, and how to avoid it? UPDATE I read somewhere that deleting all your resx files and rebuilding can help. I unthinkingly tried this. Not a good idea...

    Read the article

facebook twitter digg google delicious technorati stumbleupon myspace wordpress linkedin gmail igoogle windows live tumblr viadeo yahoo buzz yahoo mail yahoo bookmarks favorites email print

< Previous Page | 8 9 10 11 12 13 14 15 16 17 18 19  | Next Page >