There is no compiler flag to make the compiler behave in a nominal way, indeed there in principle can’t be such a flag as that would break a lot of javascript scenarios. There are several techniques generally used to emulate some kind of nominal typing. Branded types are usually used for primitives (pick one from … Read more
If you have control over all of the object types that you will be using dynamically, another option would be to force them to inherit from a subclass of the DynamicObject class that is tailored to not fail when a method that does not exist is invoked: A quick and dirty version would look like … Read more
isinstance(your_var, basestring)
What is the purpose of excess property check, in second case? It correctly detects bugs (as shown in this case, the misspelling of color) without creating too many false positives. Because the object isn’t aliased anywhere else, TypeScript can be fairly confident that the excess property isn’t going to be used for a different purpose … Read more
There’s nothing special about IDisposable here – but there is something special about iterators. Before C# 2, using this duck type on foreach was the only way you could implement a strongly-typed iterator, and also the only way of iterating over value types without boxing. I suspect that if C# and .NET had had generics … Read more
Java is by design not fit for duck typing. The way you might choose to do it is reflection: public void doSomething(Object obj) throws Exception { obj.getClass().getMethod(“getName”, new Class<?>[] {}).invoke(obj); } But I would advocate doing it in a dynamic language, such as Groovy, where it makes more sense: class Duck { quack() { println … Read more
You can access the namespace’s dictionary with vars(): >>> import argparse >>> args = argparse.Namespace() >>> args.foo = 1 >>> args.bar = [1,2,3] >>> d = vars(args) >>> d {‘foo’: 1, ‘bar’: [1, 2, 3]} You can modify the dictionary directly if you wish: >>> d[‘baz’] = ‘store me’ >>> args.baz ‘store me’ Yes, it … Read more
This is the way structural typing works. Typescript has a structural type system to best emulate how Javscript works. Since Javascript uses duck typing, any object that defines the contract can be used in any function. Typescript just tries to validate duck typing at compile time instead of at runtime. Your problem will however only … Read more
It is a term used in dynamic languages that do not have strong typing. The idea is that you don’t need a type in order to invoke an existing method on an object – if a method is defined on it, you can invoke it. The name comes from the phrase “If it looks like … Read more