But see the section "Intentional differences from Python", which is after your quote, https://docs.modular.com/mojo/why-mojo.html#intentional-differences-from-

But see the section "Intentional differences from Python", which is after your quote, https://docs.modular.com/mojo/why-mojo.html#intentional-differences-from-python https://docs.modular.com/mojo/why-mojo.html#intentional-diff... > our approach to compatibility is two fold: > 1. We utilize CPython to run all existing Python3 code “out of the box” without modification and use its runtime, unmodified, for full compatibility with the entire ecosystem. > 2. We will provide a mechanical migrator that provides very good compatibility for people who want to move Python code to Mojo. > Together, this allows Mojo to integrate well in a mostly-CPython world, but allows Mojo programmers to be able to progressively move code (a module or file at a time) to Mojo. This approach was used and proved by the Objective-C to Swift migration that Apple performed. Maybe the long-term goal is to try to make it a true superset, but it sounds like the detailed plan is more practical, to basically provide a "Python-next" language, like Swift for Objective-C.