PyUtrecht (NL) meetup: the future of Python typing - Victorien Plot¶

Tags: python, pun

(One of my summaries of the PyUtrecht meetup in Utrecht, NL).

Note: Victorien is currently the number one person maintaining Pydantic. Pydantic is basically “dataclasses with validation”.

There was a show of hands: about 70% uses type hints. Type hints has been around since python 3.5. There have been improvements during the years like str|None instead of Union[str, None] in 3.10, for instance.

Something I didn’t know: you can always introspect type hints when running your python code: typing.get_type_hints(my_func).

Getting typing-related changes into Python takes a lot of work. You need to implemeent the changes in CPython. You have to update the spec. And get it supported by the major type checkers. That’s really a difference to typescript, as typing is built-in from the start, there.

Something that helps typing in the future is 3.15’s lazy from xxx import yyy import.

There’s an upcoming PEP 764, “inline typed dictionaries”:

def get_movie() -> {"name": str, "year": int}:
    # At least something like this ^^^, I can't type that quickly :-)
    ...

He has some suggestions for a new syntax, using something like <{ .... }>, but getting a syntax change into Python takes a lot of talking and a really solid proposal.