Signatures#

Utilities for assessing Python function signature equality and compatibility, with the latter accounting for subtypes (including Generics!)

Examples#

See the test suite for a full set of examples.

Equality#

# Identical function signatures are equal.
import signatures

def foo(thing: Any) -> None:
    pass

def bar(thing: Any) -> None:
    pass

assert signatures.equal(foo, bar)

# Different function signatures are not equal.
import signatures

def foo(eggs: Any) -> None:
    pass

def bar(cheese: Any) -> None:
    pass

assert not signatures.equal(foo, bar)

Compatibility#

# A function signature is compatible with a more
# generic function signature.
from typing import TypeVar

import signatures

T = TypeVar("T", bound=int)

def foo(thing: bool) -> None:
    pass

def bar(thing: T) -> None:
    pass

assert signatures.compatible(foo, bar)

# Compatibility checks support nested Generic types.
import signatures

def foo(thing: List[Tuple[bool, str]]) -> None:
    pass

def bar(thing: List[Tuple[int, str]]) -> None:
    pass

assert signatures.compatible(foo, bar)

# A function signature is not compatible when
# Generic types are not compatible.
import signatures

def foo(thing: List[int]) -> None:
    pass

def bar(thing: List[Tuple[int, str]]) -> None:
    pass

assert not signatures.compatible(foo, bar)

License#

Copyright (c) 2022 - 2024, Joseph Hale. All Rights Reserved.

signatures by Joseph Hale is licensed under the terms of the Mozilla
Public License, v 2.0, which are available at https://mozilla.org/MPL/2.0/.

You can download the source code for signatures for free from
https://github.com/thehale/signatures.