argset 0.1.0

Description:

argset 0.1.0

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argset provides a simple interface for determining whether a callable takes
an argument with a given name, filtering a dict of potential arguments down
to just those that a callable accepts, and determining any required arguments
that are missing from a dict of potential arguments.

Installation
argset requires Python 3.6 or higher. Just use pip for Python 3 (You have pip, right?) to install
argset and its dependencies:
python3 -m pip install argset


Examples
Inspecting a function’s arguments:
>>> from argset import argset
>>> def my_func(foo, bar):
... print(f"foo={foo!r}")
... print(f"bar={bar!r}")
...
>>> a = argset(my_func)
>>> "foo" in a
True
>>> "quux" in a
False
Filtering a set of arguments to just those accepted by the function:
>>> a.select({"foo": 42, "bar": 23, "quux": 17})
{'foo': 42, 'bar': 23}
>>> my_func(**a.select({"foo": 42, "bar": 23, "quux": 17}))
foo=42
bar=23
Same as above, but now the function takes **kwargs:
>>> from argset import argset
>>> def my_func2(foo, **kwargs):
... print(f"foo={foo!r}")
... for k, v in kwargs.items():
... print(f"{k}={v!r}")
...
>>> a2 = argset(my_func2)
>>> "foo" in a2
True
>>> "quux" in a2
True
>>> a2.select({"foo": 42, "bar": 23, "quux": 17})
{'foo': 42, 'bar': 23, 'quux': 17}
>>> my_func2(**a2.select({"foo": 42, "bar": 23, "quux": 17}))
foo=42
bar=23
quux=17


API
argset(func: Callable) -> ArgSet
Inspects a callable and returns a summary of its arguments as an ArgSet
class ArgSet
A representation of the arguments taken by a callable. It has the following
attributes & properties:

required_positional_only: int
The number of arguments that are positional-only and do not have default
values

optional_positional_only: int
The number of arguments that are positional-only and have a default value

positional_only: int
The total number of positional-only arguments

required_args: frozenset[str]
The names of all positional-or-keyword or keyword-only arguments that do
not have default values

optional_args: frozenset[str]
The names of all positional-or-keyword or keyword-only arguments that have
default values

argnames: frozenset[str]
The names of all positional-or-keyword or keyword-only arguments

takes_args: bool
Whether the callable has an argument of the form *args

takes_kwargs: bool
Whether the callable has an argument of the form **kwargs


ArgSet objects support the in operator; an expression of the form
argname in a returns True iff argname is in a.argnames or
a.takes_kwargs is True.
ArgSet objects have the following methods:
ArgSet.select(kwargs: Dict[str, Any]) -> Dict[str, Any]
Returns all items in kwargs where the key is the name of a
positional-or-keyword or keyword-only argument accepted by the callable. If
takes_kwargs is True, the return value is a copy of kwargs.
ArgSet.missing(kwargs: Dict[str, Any]) -> FrozenSet[str]
Returns all keys in required_args that do not appear in kwargs