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
The dataclass decorator examines the class to find fields, by looking for names in __annotations__. It is the presence of annotation which makes the field, so, you do need an annotation. You can, however, use a generic one: @dataclass class Favs: fav_number: int = 80085 fav_duck: ‘typing.Any’ = object() fav_word: str=”potato”
A lot of the comments for duck typing don’t really substantiate the claims. Not “having to worry” about a type is not sustainable for maintenance or making an application extendable. I’ve really had a good opportunity to see Grails in action over my last contract and its quite funny to watch really. Everyone is happy … 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
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
Polymorphism (in the context of object-oriented programming) means a subclass can override a method of the base class. This means a method of a class can do different things in subclasses. For example: a class Animal can have a method talk() and the subclasses Dog and Cat of Animal can let the method talk() make … Read more
In some of the answers here, I’ve seen some incorrect use of terminology, which has lead people to provide wrong answers. So, before I give my answer, I’m going to provide a few definitions: Strongly typed A language is strongly typed if it enforces the type safety of a program. That means that it guarantees … Read more
To me C++ templates are a compile-time version of duck typing. The compiler will compile e.g. Class and as long as your Duck has all needed types it will instantiate a class. If something is not correct(e.g. copy constructor missing) the compilation fails. The counterpart in real ducktyping is a failure when you call a … Read more
isinstance(your_var, basestring)
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