interface

问题 Firstly, this question isn't 100% specific to Haskell, feel free to comment on the general design of typeclasses, interfaces and types. I'm reading LYAH - creating types and typeclasses The following is the passage that I'm looking for more information on: Data (Ord k) => Map k v = ... However, it's a very strong convention in Haskell to never add typeclass constraints in data declarations. Why? Well, because we don't benefit a lot, but we end up writing more class constraints, even when we

问题 I want to create an interface for "Items". Typicaly I would name an interface by adding and "I" prefix to a base word. But in this case my base word already starts with an I. Here are a couple ideas I've had IItem : Two I's Iitem : Vary the case ItemInterface : Skip the I prefix and write out Interface What looks the best? Has anyone else run into this problem. If so what did you do? 回答1: Although hard to read, IItem would be in line with some existing " II " interfaces: IItem in Windows

问题 Does it ever make sense to override a pure virtual method with another pure virtual method? Are there any functional differences or perhaps code style reasons to prefer one of the following options over the other? class Interface { public: virtual int method() = 0; }; class Abstract : public Interface { public: int method() override = 0; }; class Implementation : public Abstract { public: int method() override { return 42; } }; Versus: class Interface { public: virtual int method() = 0; };

问题 Using Delphi XE. When trying to access a Delphi interface object from a DLL, it fails if I try to do it dynamically versus statically. The interface unit in the dll implements a function to return an instance of the interface. When linked statically, the result is nil when entering the function and everything works. When loading dynamically, the result is non-nil, so when the assignment to result is being done, the IntFCopy code sees it as non-nil and so tries to free it before the assignment

问题 I have written my own GUI for playing and teaching chess. The GUI was written using HTML for the appearance, and JavaScript for the behavior of the pieces. Currently the program does not follow any of the rules of chess. It is up to the user to follow the rules of chess correctly. This allows the freedom to set up illegal positions or move the same side multiple times. This is very useful when trying to teach chess to beginners. I am now looking at the idea that I would like to hook my

问题 I have written my own GUI for playing and teaching chess. The GUI was written using HTML for the appearance, and JavaScript for the behavior of the pieces. Currently the program does not follow any of the rules of chess. It is up to the user to follow the rules of chess correctly. This allows the freedom to set up illegal positions or move the same side multiple times. This is very useful when trying to teach chess to beginners. I am now looking at the idea that I would like to hook my

问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed last year . I'm having a hard time trying to get my team comfortable with interface based programming ... anyone have some suggestions? 回答1: In order to help your team get comfortable with the idea, the best route would be to demonstrate what interface-based development can accomplish and

问题 I'm trying to bind an Activity to a LocalService to interact with it. But in my Activity I am only able to make calls to methods defined in my LocalBinder and not in my LocalService. What am I doing wrong? Not starting scratch I read another question and I have read a little how to code some sample code and my code resembles that sample code. Also I have been reading some of the Service Documentation for convenience here is a small quote from that section of the documentation: "A service is

问题 The question is not only regarding the headline, but more of a "how will I achieve this, without trying to force a Java/Flash design into an Objective C (iPhone)program". I have 6 views that extends UIView, these views all have different behavior but share certain methods, like -(void) update and -(void) changeState:(NSInteger)state . A viewController, whose job is it to update, instantiate and display these views has a switch block to do this. So switch(4) {...} instantiates UIView4, but as

问题 I realize that in most cases, it's preferred in Python to just access attributes directly, since there's no real concept of encapsulation like there is in Java and the like. However, I'm wondering if there aren't any exceptions, particularly with abstract classes that have disparate implementations. Let's say I'm writing a bunch of abstract classes (because I am) and that they represent things having to do with version control systems like repositories and revisions (because they do).