unique_defaults
Replace a function's default values with objects unique to each function call. This allows writing signatures with mutable defaults without sharing the underlying object between funciton calls.
from unique_defaults import unique_lists
def classic(a=[]):
a.append("again")
return " ".join(a)
classic() == "again"
classic() == "again again"
@unique_lists
def unique(a=[]):
a.append("again")
return " ".join(a)
unique() == "again"
unique() == "again"
Using the mutable object directly in the function signature leads to shorter and more accurate annotations, as well as simplifying the function's logic.
from typing import List, Optional
from unique_defaults import unique_lists
def classic(a: Optional[List] = None):
if a is None:
a = []
a.append("again")
return " ".join(a)
classic() == again
classic() == again
@unique_lists
def unique(a: List = []):
a.append("again")
return " ".join(a)
unique() == again
unique() == again