apply-defaults 0.1.1

Apply values to optional params

apply_defaults

Apply default values to functions.

Makes configuration easy! Application settings come from a config file into your code cleanly and with minimal effort.

No more val = val if val is not None else config.val if 'val' in config else val ugliness.

pip install apply_defaults

apply_config

This decorator applies options from a ConfigParser object.

from apply_defaults import apply_config
from configparser import ConfigParser

config = ConfigParser()
config.read_dict({"general": {"option": True}})  # alteratively read a file

@apply_config(config)
def func(option: bool = False) -> bool:
    return option

The option parameter takes the value from the configuration.

>>> func()
True

Override the configuration by passing a value.

>>> func(option=False)
'False'

If the option is not in the configuration, the default value from the parameter list is used.

>>> config.remove_option("general", "option")
>>> func()
False

Note: ConfigParser's options are strings. Type hints in the function signature allow the apply_config decorator to cast options to the desired type. Alternatively cast the value yourself.

apply_self

This decorator applies attributes from the bound object.

from apply_defaults import apply_self

class MyObject:
    def __init__(self):
        self.option = True

    @apply_self
    def func(self, option=False):
        return value

Type hints allow the decorator to cast the config option to the desired type. Otherwise, the config option will be a string every time.

The parameter takes the value from the bound object, i.e. self.foo.

>>> obj = MyObject()
>>> obj.func()
True

Override by passing a value.

>>> obj.func(option=False)
False

If the attribute is not in the bound object, the default value from the parameter list is used.

>>> del obj.option
>>> obj.func()
False