duck-typing

问题 There was an earlier question (8 years ago!) about the relationship between templates and duck typing here: What's the relationship between C++ template and duck typing? I've borrowed and modified the tag line for my question on a new feature of C++. With C++20 there will be the new feature of "concept" that looks much more like a duck-typing feature. Is it correct that the new C++ "concept" is equivalent to duck typing for C++? If not, how is it different? 回答1: With C++20 there will be the

问题 C++ has some sort of duck typing for types given by template parameters. We have no idea what type DUCK1 and DUCK2 will be, but as long as they can quack() , it will compile and run: template <class DUCK1, class DUCK2> void let_them_quack(DUCK1* donald, DUCK2* daisy){ donald->quack(); daisy->quack(); } But it's a bit inconvenient to write. When I do absolutely not care what actual types DUCK1 and DUCK2 are but rather want to fully use the idea of duck typing, then I would like to have

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 6 years ago . Improve this question I see many saying "eval is evil/dangerous/insecure", because one can do things like: eval("os.system('rm -rf /')") while in other posts, pythoner are considered as " consenting adults ", you don't have to do type checking because of python is of style

问题 Looks like in TypeScript it's absolutely fine (from the compiler perspective) to have such code: class Vehicle { public run(): void { console.log('Vehicle.run'); } } class Task { public run(): void { console.log('Task.run'); } } function runTask(t: Task) { t.run(); } runTask(new Task()); runTask(new Vehicle()); But at the same time I would expect a compilation error , because Vehicle and Task don't have anything in common. And sane usages can be implemented via explicit interface definition:

来源： https://stackoverflow.com/questions/64185810/how-can-i-use-static-checking-to-ensure-an-object-has-a-certain-method-attribute

来源： https://stackoverflow.com/questions/64185810/how-can-i-use-static-checking-to-ensure-an-object-has-a-certain-method-attribute

来源： https://stackoverflow.com/questions/64185810/how-can-i-use-static-checking-to-ensure-an-object-has-a-certain-method-attribute

问题 This question already has answers here : How to use type hints in python 3.6? (3 answers) Closed 13 days ago . The typing module implements type hints in Python 3.5+. However, this is not enforced, it seems to currently only exist for the benefit of static type checkers such as mypy and PyCharm. I was hoping it would be a viable alternative to duck typing. Question : Is there a way to turn on dynamic type checking in Python 3.7+ that I didn't find in Google search? So for example, if I define

问题 I have an object handed into our library and passed through various processes. I need to attach some additional information to these objects as they pass through various stages and out the other end - a kind of dynamic decorator pattern, I guess, except adding additional properties rather than changing existing behaviour. I was hoping to use LinFu or Castle to create a dynamic proxy and implement an additional interface on the object to store this. Components that know about the extended

问题 Below syntax, interface StringArray { [index: number]: string; } states that when a StringArray is indexed with a number , it will return a string . For example - let myArray: StringArray;myArray = ["Bob", "Fred"];let myStr: string = myArray[0]; So, myArray is type constrained on values stored as string type, by declaring it with type StringArray . Key(index) is always string type, under the hood(JavaScript), despite mentioning it as number From the below syntax, class Animal{ name: string; }