4 ms·

No interfaces? from collections.abc import Sequence Slower? import numpy as np

• andreygrehov 8y ago
  You're referring to duck typing, which to me contradicts the Zen of Python: Explicit is better than implicit. > Slower? Yes, overall the language is slower than PHP. It's not a bad thing, just the result of benchmarks. It doesn't mean one should stop writing Python.
  • xapata 8y ago
    No, I'm not referring to duck typing. An abstract base class enforces the interface. Explicitly. Some benchmarks might be slower, but I don't know anyone doing high-performance computing with PHP. I do see the topic at Python conferences.
    • andreygrehov 8y ago
      abstract base class != interface
      • xapata 8y ago
        Right, they're even better than Interfaces: both a contract and a partial implementation. No need for an "Interface" when you've got ABCs.
        • andreygrehov 8y ago
          I see what you mean, but to me abstract classes are distinct from interfaces. Abstract class answers the question "what an object is?", whereas an interface is about what the object can do.
          • xapata 8y ago
            That distinction is unnecessary.
          • dragonwriter 8y ago
            The distinction between what an object is and what an object can do is an artifact of bad object modelling (specifically, single inheritance OOP.) Any “can do” set has an exactly corresponding “is a thing that can do” set, so there is no logical need for different constructs to model “is” sets and “can do” sets.
            • andreygrehov 8y ago
              Sounds like a controversial statement and I'm not sure how universal true this is. I'll give it a thought. Thank you.
              • xapata 8y ago
                Another way of explaining this is that Interfaces are Java's way to compensate for the lack of multiple inheritance. There's more than one variety of inheritance. Both Python and Java chose implementation-inheritance, meaning that the children get to use not only the interface, but also the implementation of the parent. For some reason, I'm not quite sure why, the Java folks thought that multiple implementation-inheritance would cause too many problems. They still recognized it's useful, so they provided a 2nd form of inheritance that supports multiple parents, interface-inheritance. There are more varieties of inheritance that a language could choose, for example, prototypes like JavaScript.
                • andreygrehov 8y ago
                  Yes, I'm familiar with all of that, but isn't the Diamond of Death [1] is the exact reason why they did it? [1] https://en.wikipedia.org/wiki/Multiple_inheritance#The_diamond_problem https://en.wikipedia.org/wiki/Multiple_inheritance#The_diamo...
      • kjeetgill 8y ago
        Let me help you two out: ABCs are like interfaces in they can be used to enforce properties (like the presence of particular functions) of a class that extends/impliments them; BUT, interfaces can also be used to enforce a particular variable always refers to something with certain properties (without worrying about what it is concretely).