Description

jsrozner

opened on Apr 5, 2024

Issue body actions

Consider the example in 24-class-metaprog/factories.py (corresponds to example 24-2, page 912 in my copy)

Dog = record_factory('Dog', 'name weight owner') 
rex = Dog('Rex', 30, 'Bob')

We do not get static type checking on, e.g., rex.name

Is there an easy fix, or is this because types in metaclasses / metaprogramming are hard?

Activity

1. ramalho commented on Apr 11, 2024

   

   ramalho

   on Apr 11, 2024

   Member

   More actions

   We do not get static type checking because all effects of metaprogramming happen at runtime, and a static type checker does not run your program. It can only analyze the static source code, and it is not smart enough to understand what record_factory does, or that the string `'name weight owner' is actually naming attributes of a class that will be built at runtime.
2. ramalho commented on Apr 11, 2024

   

   ramalho

   on Apr 11, 2024

   Member

   More actions

   This is an interesting question, so I will leave the issue open until I work on chapter 24 for the third edition, hopefully in 2025.

   Thanks, @jsrozner !

   Reacted by Josh

Issue actions