cara/cara/dataclass_utils.py

26 lines
913 B
Python

import dataclasses
import typing
def nested_replace(obj, new_values: typing.Dict[str, typing.Any]):
"""Replace an attribute on a dataclass, much like dataclasses.replace,
except it supports nested replacement definitions. For example:
>>> new_obj = nested_replace(obj, {'attr1.sub_attr2.sub_sub_attr3': 4})
>>> new_obj.attr1.sub_attr2.sub_sub_attr3
4
"""
new_inst = obj
for name, value in new_values.items():
if '.' in name:
# Recurse into the desired name and come out with a top-level
# dataclass which has been updated appropriately.
name, remainder = name.split('.', 1)
value = nested_replace(
getattr(new_inst, name),
{remainder: value}
)
# We have a plain old name. So set it.
new_inst = dataclasses.replace(new_inst, **{name: value})
return new_inst