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  • Template does not exist: 500.html

    - by xRobot
    I have created a template for 500 http error. I have insert my template 500.html in: 1) /project/ 2) /project/templates/ 3) /python2.5/ 4) /python2.5/templates/ . but I always get this error: TemplateDoesNotExist: 500.html Same problem for Http 404 error. WHY ???

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  • Sharepoint Custom Field default template

    - by Mina Samy
    Hi all I want to develop a custom lookup field for sharepoint. I created a class as the following public class CustomLookupControl:BaseFieldControl and overided this method protected override string DefaultTemplateName { get { return base.DefaultTemplateName; } } but when I edit an item I find that the place of the field is empty. my question is that I don't want to implement a custom rendering template for the field, I want to use the default template of the lookup field how can this be achieved.

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  • [C++] Multiple inheritance from template class

    - by Tom P.
    Hello, I'm having issues with multiple inheritance from different instantiations of the same template class. Specifically, I'm trying to do this: template <class T> class Base { public: Base() : obj(NULL) { } virtual ~Base() { if( obj != NULL ) delete obj; } template <class T> T* createBase() { obj = new T(); return obj; } protected: T* obj; }; class Something { // ... }; class SomethingElse { // ... }; class Derived : public Base<Something>, public Base<SomethingElse> { }; int main() { Derived* d = new Derived(); Something* smth1 = d->createBase<Something>(); SomethingElse* smth2 = d->createBase<SomethingElse>(); delete d; return 0; } When I try to compile the above code, I get the following errors: 1>[...](41) : error C2440: '=' : cannot convert from 'SomethingElse *' to 'Something *' 1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast 1> [...](71) : see reference to function template instantiation 'T *Base<Something>::createBase<SomethingElse>(void)' being compiled 1> with 1> [ 1> T=SomethingElse 1> ] 1>[...](43) : error C2440: 'return' : cannot convert from 'Something *' to 'SomethingElse *' 1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast The issue seems to be ambiguity due to member obj being inherited from both Base< Something and Base< SomethingElse , and I can work around it by disambiguating my calls to createBase: Something* smth1 = d->Base<Something>::createBase<Something>(); SomethingElse* smth2 = d->Base<SomethingElse>::createBase<SomethingElse>(); However, this solution is dreadfully impractical, syntactically speaking, and I'd prefer something more elegant. Moreover, I'm puzzled by the first error message. It seems to imply that there is an instantiation createBase< SomethingElse in Base< Something , but how is that even possible? Any information or advice regarding this issue would be much appreciated.

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  • Why is writing a compiler in a functional language so efficient and easier?

    - by wvd
    Hello all, I've been thinking of this question very long, but really couldn't find the answer on Google as well a similar question on Stackoverflow. If there is a duplicate, I'm sorry for that. A lot of people seem to say that writing compilers and other language tools in functional languages such as OCaml and Haskell is much more efficient and easier then writing them in imperative languages. Is this true? And if so -- why is so efficient and easy to write them in functional languages instead of in an imperative language, like C? Also -- isn't a language tool in a functional language slower then in some low-level language like C? Thanks in advance, William v. Doorn

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  • Why is writing a compiler in a functional language easier?

    - by wvd
    Hello all, I've been thinking of this question very long, but really couldn't find the answer on Google as well a similar question on Stackoverflow. If there is a duplicate, I'm sorry for that. A lot of people seem to say that writing compilers and other language tools in functional languages such as OCaml and Haskell is much more efficient and easier then writing them in imperative languages. Is this true? And if so -- why is it so efficient and easy to write them in functional languages instead of in an imperative language, like C? Also -- isn't a language tool in a functional language slower then in some low-level language like C? Thanks in advance, William v. Doorn

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  • Returning modified data to a template

    - by Duncan
    I need to amend QuerySet data when i return it to a template. for example, model.objects.all() returns a date (with other fields), but i also want to return the number of days since that date has passed. This is so that in the template, i can say "you last logged in 4 days ago". What is the best way to do this?

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  • T4 template for Validation in MVC

    - by GibboK
    I'm using ASp.Net MVC and EF 4.3.1. Using POCO t4 template I'm able to create the POCO classes for my model but not validation. At the moment I'm using Partial Classes with MetaData for adding the annotation (leaving intact the POCO auto generated). My question: Could you point me out a tutorial, or show me an example of code or a link to a T4 template the also include automatic VALIDATION for my POCO? THanks

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  • Why isn't my IO executed in order?

    - by HaskellElephant
    Hi, I'm having some fun learning about the haskell IO. However in my recent exploration of it I have encountered some problems with IO not executing in order, even inside a do construct. In the following code I am just keeping track of what cards are left, where the card is a tuple of chars (one for suit and one for value) then the user is continously asked for wich cards have been played. I want the putStr to be executed between each input, and not at the very end like it is now. module Main where main = doLoop cards doLoop xs = do putStr $ show xs s <- getChar n <- getChar doLoop $ remove (s,n) xs suits = "SCDH" vals = "A23456789JQK" cards = [(s,n) | s <- suits, n <- vals] type Card = (Char,Char) remove :: Card -> [Card] -> [Card] remove card xs = filter (/= card) xs

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  • Missing something with Reader monad - passing the damn thing around everywhere

    - by Richard Huxton
    Learning Haskell, managing syntax, have a rough grasp of what monads etc are about but I'm clearly missing something. In main I can read my config file, and supply it as runReader (somefunc) myEnv just fine. But somefunc doesn't need access to the myEnv the reader supplies, nor do the next couple in the chain. The function that needs something from myEnv is a tiny leaf function. So - how do I get access to the environment in a function without tagging all the intervening functions as (Reader Env)? That can't be right because otherwise you'd just pass myEnv around in the first place. And passing unused parameters through multiple levels of functions is just ugly (isn't it?). There are plenty of examples I can find on the net but they all seem to have only one level between runReader and accessing the environment.

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  • inspect C++ template instantiation

    - by aaa
    hello. Is there some utility which would allow me to inspect template instantiation? my compiler is g++ or Intel. Specific points I would like: Step by step instantiation. Instantiation backtrace (can hack this by crashing compiler. Better method?) Inspection of template parameters. Thanks

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  • Alias for a C++ template?

    - by porgarmingduod
    typedef boost::interprocess::managed_shared_memory::segment_manager segment_manager_t; // Works fine, segment_manager is a class typedef boost::interprocess::adaptive_pool allocator_t; // Can't do this, adaptive_pool is a template The idea is that if I want to switch between boost interprocess' several different options for shared memory and allocators, I just modify the typedefs. Unfortunately the allocators are templates, so I can't typedef the allocator I want to use. Is there a way to achieve an alias to a template in C++? (Except for the obvious #define ALLOCATOR_T boost::interprocess::adaptive_pool)

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  • Type signature "Maybe a" doesn't like "Just [Event]"

    - by sisif
    I'm still learning Haskell and need help with the type inference please! Using packages SDL and Yampa I get the following type signature from FRP.Yampa.reactimate: (Bool -> IO (DTime, Maybe a)) and I want to use it for: myInput :: Bool -> IO (DTime, Maybe [SDL.Event]) myInput isBlocking = do event <- SDL.pollEvent return (1, Just [event]) ... reactimate myInit myInput myOutput mySF but it says Couldn't match expected type `()' against inferred type `[SDL.Event]' Expected type: IO (DTime, Maybe ()) Inferred type: IO (DTime, Maybe [SDL.Event]) In the second argument of `reactimate', namely `input' In the expression: reactimate initialize input output process I thought Maybe a allows me to use anything, even a SDL.Event list? Why is it expecting Maybe () when the type signature is actually Maybe a? Why does it want an empty tuple, or a function taking no arguments, or what is () supposed to be?

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  • Population count of rightmost n integers

    - by Jason Baker
    I'm implementing Bagwell's Ideal Hash Trie in Haskell. To find an element in a sub-trie, he says to do the following: Finding the arc for a symbol s, requires ?nding its corresponding bit in the bit map and then counting the one bits below it in the map to compute an index into the ordered sub-trie. What is the best way to do this? It sounds like the most straightforward way of doing this is to select the bits below that bit and do a population count on the resulting number. Is there a faster or better way to do this?

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  • template; operator (int)

    - by Oops
    Hi, regarding my Point struct already mentioned here: http://stackoverflow.com/questions/2794369/template-class-ctor-against-function-new-c-standard is there a chance to replace the function toint() with a cast-operator (int)? namespace point { template < unsigned int dims, typename T > struct Point { T X[ dims ]; //umm??? template < typename U > Point< dims, U > operator U() const { Point< dims, U > ret; std::copy( X, X + dims, ret.X ); return ret; } //umm??? Point< dims, int > operator int() const { Point<dims, int> ret; std::copy( X, X + dims, ret.X ); return ret; } //OK Point<dims, int> toint() { Point<dims, int> ret; std::copy( X, X + dims, ret.X ); return ret; } }; //struct Point template < typename T > Point< 2, T > Create( T X0, T X1 ) { Point< 2, T > ret; ret.X[ 0 ] = X0; ret.X[ 1 ] = X1; return ret; } }; //namespace point int main(void) { using namespace point; Point< 2, double > p2d = point::Create( 12.3, 34.5 ); Point< 2, int > p2i = (int)p2d; //äähhm??? std::cout << p2d.str() << std::endl; char c; std::cin >> c; return 0; } I think the problem is here that C++ cannot distinguish between different return types? many thanks in advance. regards Oops

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  • (newbie) type signature "Maybe a" doesn't like "Just [Event]"

    - by sisif
    i'm still learning Haskell and need help with the type inference please! using packages SDL and Yampa i get the following type signature from FRP.Yampa.reactimate: (Bool -> IO (DTime, Maybe a)) and i want to use it for: myInput :: Bool -> IO (DTime, Maybe [SDL.Event]) myInput isBlocking = do event <- SDL.pollEvent return (1, Just [event]) ... reactimate myInit myInput myOutput mySF but it says Couldn't match expected type `()' against inferred type `[SDL.Event]' Expected type: IO (DTime, Maybe ()) Inferred type: IO (DTime, Maybe [SDL.Event]) In the second argument of `reactimate', namely `input' In the expression: reactimate initialize input output process i thought "Maybe a" allows me to use anything, even a SDL.Event list? why is it expecting "Maybe ()" when the type signature is actually "Maybe a"? why does it want an empty tuple, or a function taking no arguments, or what is () supposed to be?

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  • Last element not getting insert in Tree

    - by rdk1992
    So I was asked to make a Binary Tree in Haskell taking as input a list of Integers. Below is my code. My problem is that the last element of the list is not getting inserted in the Tree. For example [1,2,3,4] it only inserts to the tree until "3" and 4 is not inserted in the Tree. data ArbolBinario a = Node a (ArbolBinario a) (ArbolBinario a) | EmptyNode deriving(Show) insert(x) EmptyNode= insert(tail x) (Node (head x) EmptyNode EmptyNode) insert(x) (Node e izq der) |x == [] = EmptyNode --I added this line to fix the Prelude.Head Empty List error, after I added this line the last element started to be ignored and not inserted in the tree |head x == e = (Node e izq der) |head x < e = (Node e (insert x izq) der) |head x > e = (Node e izq (insert x der)) Any ideas on whats going on here? Help is much appreciated

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  • Cartesian Plane

    - by NuNu
    I'm trying to define a function in Haskell that takes an integer argument c and returns the list of all points on the cartesian plane of the form (x/c,y/c) where x and y are integers. x/c is between -2 and 1 and y/r is between -1 and 1 This is what I've gotten so far which I'm almost sure is right but I'm getting a parse error on input = when I run it particularly at this line: cart xs ys c = [(y/c,x/c) | x <- xs, y <- ys] plane :: Int -> [a] plane c = cart [-1*c .. 1*c] [-2*c .. 1*c] c cart xs ys c = [(y/c,x/c) | x <- xs, y <- ys] A sample output would be: plane 1 would generate: [(-2.0, -1.0), (-1.0, -1.0), ( 0.0, -1.0), ( 1.0, -1.0), (-2.0, 0.0), (-1.0, 0.0), ( 0.0, 0.0), ( 1.0, 0.0), (-2.0, 1.0), (-1.0, 1.0), ( 0.0, 1.0), ( 1.0, 1.0)] Anyone have any idea how I can fix this! Thanks

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  • Multiplying numbers on horizontal, vertial, and diagonal lines

    - by untwisted
    I'm currently working on a project Euler problem (www.projecteuler.net) for fun but have hit a stumbling block. One of the problem provides a 20x20 grid of numbers and asks for the greatest product of 4 numbers on a straight line. This line can be either horizontal, vertical, or diagonal. Using a procedural language I'd have no problem solving this, but part of my motivation for doing these problems in the first place is to gain more experience and learn more Haskell. As of right now I'm reading in the grid and converting it to a list of list of ints, eg -- [[Int]]. This makes the horizontal multiplication trivial, and by transposing this grid the vertical also becomes trivial. The diagonal is what is giving me trouble. I've thought of a few ways where I could use explicit array slicing or indexing, to get a solution, but it seems overly complicated and hackey. I believe there is probably an elegant, functional solution here, and I'd love to hear what others can come up with.

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  • Using type passed as a template in C++

    - by MeDiCS
    Is it possible to actually use the type passed as a template for control flow? I'd like to write a function that uses templates, which in turn calls another function based on the type passed: template <class T> void test_function (T var) { //Do stuff if (T == char) { bar (var); } else { foo (var); } //Do even more stuff } If not, I'll have to fallback to enums...

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  • C++ Template Usage

    - by MalcomTucker
    If I have a template definition like the one below, can someone provide a code sample for how I would actually instantiate an instance of this with two of my own classes? template <class T1, class T2> class LookUpTable { public: LookUpTable(); void set(Tl x, T2* y); T2* get(Tl x); }; Thanks.

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