generic-programming

问题 operator& for CComPtr is overloaded, which makes my generically written code crash. I am wondering if there is any way to force a variable into returning the address of it's object? 回答1: The solution is hideous: reinterpret_cast<CComPtr*>(&reinterpret_cast<char&>(ptr)) 回答2: If you can use boost, consider using: addressof, if you cannot, take a look at the implementation. 回答3: You could cast the CComPtr to a CComPtrBase , which, from what I can gather from the MSDN page, has no overloaded

问题 Here is some C++ template code from Programming Language Pragmatics, by Scott template<typename T> class chooser { public: virtual bool operator()(const T& a, const T& b) = 0; }; template<typename T, typename C> class arbiter { T* best_so_far; C comp; public: arbiter() { best_so_far = nullptr; } void consider(T* t) { if (!best_so_far || comp(*t, *best_so_far)) best_so_far = t; } T* best() { return best_so_far; } }; class case_sensitive : chooser<string> { public: bool operator()(const string&

问题 I'm learning about SYB and rank n types, and came across a confusing case of what seems like the monomorphism restriction. I wrote a function to find the shallowest entry that matches a predicate. Instead of a reducing function, I wanted to accept a more predicate-like function using Alternative , and transform it into a generic function myself. I decided to omit the type annotation in the let block to see how the monomorphism reduction would affect the type in this implementation: shallowest

问题 A queue implementaion using an array but i m getting an exception. I have an interface named as Queue with generic ArrayQueue as implemented class of Queue Interface ArrayQueueTest as my main class to test the code. public interface Queue<E> { public void enqueue(E e);//insert an element in a queue public E dequeue();/delete an element in queue and return that element public int size();//give the number of elements in an queue public E first();//give the first element of queue if any but not

问题 I'm having problems trying to pass an Integer object from a driver class as an argument for function of a SortedArray Generic class I created. From my driver class, I convert the user's int input into an Integer object to be cast onto Comparable of my SortedArray class. I continue to receive the error: "Exception in thread "main" java.lang.ClassCastException: java.lang.Integer cannot be cast to Comparable". I took a look at some of my classmates' source codes only to find little difference in

问题 I'm trying to understand how to implement a generic trait in Rust. While I've seen a number of examples, the examples are too tied to a specific use (e.g. genomic mutators) for me to be able to understand at this point in my Rust development. Instead, here's a simple example based on something fairly universal--incrementing: trait Incrementable { fn post_inc(&mut self) -> Self; fn post_inc_by(&mut self, n: usize) -> Self; } impl Incrementable for usize { fn post_inc(&mut self) -> Self { let

问题 Python has a very useful feature of function decorators, which, moreover, allows composition. For example, if write a function foo , then you can state that you would like foo to be memoized, but also retried more than a single time in case of a cache miss in which foo also raises an exception, by: @lru_cache @retry def foo(...): Decorator composability allows developing functions like foo and individual function decorators independently, and then mixing them as needed. It would be nice if we

问题 Python has a very useful feature of function decorators, which, moreover, allows composition. For example, if write a function foo , then you can state that you would like foo to be memoized, but also retried more than a single time in case of a cache miss in which foo also raises an exception, by: @lru_cache @retry def foo(...): Decorator composability allows developing functions like foo and individual function decorators independently, and then mixing them as needed. It would be nice if we

问题 Sorry if the question isn't too clear. I'm not sure the best way to phrase it (feel free to edit!). I think an example would be the most clear: I am attempting to define a Monad concept based off of the Haskell definition. The bind operator ( >>= ) requires that a Monad of type A can be bound to a function that takes an A and returns a Monad of type B . I can define A in terms of a value_type typedef but how do I define type B in my concept? template <typename M> concept bool Monad() { return

问题 Is there a way to create a data template that handles a list of items? I have Contact.Phones ( EntityCollection<Phone> ) and I want the data template to handle the list - add remove edit etc. Is there a way to set the DataType property of the DataTemplate to generic EntityCollection<Phone> ? 回答1: Wrap your generic list in a new class, which subclasses your generic list without adding anything. This makes it possible to bind to the list from XAML. This is described here: Can I specify a