Re:Python's “Disappointing” Superpowers
by ReflectedImage on Thursday February 02, 2023 @02:05PM
(#34631524)
"a proper type checker goes far beyond that"
But if it can't catch 60% of all errors and it can't. Then it's worse than dynamic typing.
This isn't complicated. If you are excluding performance, then static typing is inferior to dynamic typing. It's that simple. No ifs, no buts.
I do write statically typed code but that's for performance critical code. Since I've got good experience of both, I understand the differences very well.
I assure you that using static typing in a scripting language like Python is a mindnumbingly stupid thing to do.
I don't work alone. Most of the time, I work on projects that predate my involvement, and are old enough to have accumulated cruft.
But I think I found the disconnect. This right here is the key:
> since the vast majority of bugs are logic bugs
You might think that there is no way a type checker could prevent a logic bug. You're wrong. It is clear to me now that when you say 3%, you are talking not about the type of bugs that static type checkers are capable of preventing, but only errors that are explicitly related to types. Because if you model your code with types as you go, types do prevent all kinds of logic errors. When you write code with strong typing, it can prevent impossible state machine transitions, ensure that you handle all cases of a set of possibilities, ensure that you follow API contract obligations, and more.
Exactly how much a given type system is capable of inferring and decoding varies. TypeScript is definitely the state of the art for type erasure systems built on script languages, and what it is capable of encoding is pretty impressive.
Maybe, maybe, the amount of bugs that you can attribute to typing issues is 3% if we're only regarding Python TypeErrors; but, a proper type checker goes far beyond that.