Things I dislike

• Missing
  • Multiline lambdas
    • With statements
  • Mutable variable references across scope (or: mutating rather than new binding in loops etc.), e.g. par_map((lambda: f(x)) for x in xs)
• Typing is terrible
  • Also, state of tools: e.g. typing async with asynccontextmanagers() as ...
• 4 spaces!
• GIL
• Perf
• Async (generically)

Typing woes

• mostly just makes me miss typescript
• no mapped types
• no utility types
• TypedDict very limited, e.g. can only say “expect a dict with exactly these key” rather than “a superset of these keys”
• no way to get the arguments of a function as a type, e.g. to type a dict of kwargs
  • py3.12 will have Unpack but that’s not really the right direction
• unclear what is type level vs value level, where the limits are of analysis
• typevartuples won’t
• dataclass_transformer is a special case for things like dataclasses, pydantic, FieldClass: https://typing.readthedocs.io/en/latest/spec/dataclasses.html#dataclass-transform

Exceptions

• Python 3 no longer supports raise type, instance, traceback . Instead, do raise error.with_traceback(sys.exc_info()[2]).
• Python 3 supports chaining: raise RuntimeError('specific message') from error.
• Re-raising/chaining exceptions:
  • raise re-raises exactly what was raised before, with the original traceback.
  • raise error combines their stacks.
  • raise Exception() from error shows both errors and The above exception was the direct cause of the following exception.