LoopyLuci Advanced Python Typing
Implementing advanced Python typing — from generics and protocols through variadic generics, type narrowing, and mypy strict mode.
When to Use
- Type-safe Python codebases at scale
- Generic functions and classes
- Structural subtyping with Protocol
- Custom type guards and narrowing
Typing Patterns
from typing import TypeVar, Protocol, Generic, overload
T = TypeVar('T')
S = TypeVar('S')
class Comparable(Protocol):
def __lt__(self, other) -> bool: ...
class Stack(Generic[T]):
def __init__(self): self.items: list[T] = []
def push(self, item: T) -> None: self.items.append(item)
def pop(self) -> T: return self.items.pop()
@overload
def process(x: int) -> str: ...
@overload
def process(x: str) -> int: ...
def process(x):
if isinstance(x, int): return str(x)
return int(x)
Verification Checklist
- TypeVar for generic functions and classes
- Protocol for structural subtyping
- @overload for type-specific signatures
- Literal, TypedDict, Final type constructs
- mypy --strict compliance