Writing forward-compatible software in Python

Python 3 is the future of Python. However there might be a problem in the community if both Python 3 and 2 coexist. The former one was great and brilliant, but it is time to start writing software in the new version in order to move towards new features and improvements.

Let's start by the beginning. One of the reasons I always preferred Python over the rest of the programming languages is because it is more advanced, meaning that included many concepts that other languages did not. For example, think of how early Python adopted ideas like lambda functions, dynamic typing, duck typing, context managers, metaclasses and so on, while other technologies (namely Java, C++ for example¹) were still using data structures and calling them "objects". Python has always been many steps ahead.

Great news are that this is no over: Python is still improving at a fast pace. And that is precisely the issue with Python 3. As a result of that evolution, the new version of Python must change some of its internals in order to properly implement new features, and this is what lead it to be incompatible with earlier versions, which should not be a problem. But it seems it is.

Some developers do not like the new release, and they are not keen on migrating the code base. They argue that Python 3 "is wrong" because it is not backwards compatible, but my question here is why are we thinking backwards instead of forwards. A programming language as a model or concept, must evolve, improve, so we should be thinking on the future of the language rather that on its past. I think they are missing the new ideas, the way Python is changing in order to incorporate more efficient mechanisms. Perhaps this time, the leap was too big.

I think the best for the language is to adopt its new version, and do not think of it as a different one. Therefore, when we say "Python", it should be understood that we are talking about just one single version.