tldr

from inference_logic import Variable, Rule, search

X, Y, Z, C, P = Variable.factory("X", "Y", "Z", "C", "P")

db = [
    dict(parent="Abe", child="Homer"),
    dict(parent="Homer", child="Lisa"),
    dict(parent="Homer", child="Bart"),
    dict(parent="Homer", child="Maggie"),
    Rule(dict(ancestor=X, descendant=Z), dict(parent=X, child=Z)),
    Rule(
        dict(ancestor=X, descendant=Z),
        dict(parent=X, child=Y),
        dict(ancestor=Y, descendant=Z),
    ),
]

query = dict(ancestor=P, descendant=C)
results = search(db, query)


assert next(results) == {C: "Lisa", P: "Abe"}
assert next(results) == {C: "Bart", P: "Abe"}
assert next(results) == {C: "Maggie", P: "Abe"}
assert next(results) == {C: "Homer", P: "Abe"}
assert next(results) == {C: "Lisa", P: "Homer"}
assert next(results) == {C: "Bart", P: "Homer"}
assert next(results) == {C: "Maggie", P: "Homer"}

Credits

This package was created with Cookiecutter and the audreyr/cookiecutter-pypackage project template.

This was originally inspired by py4fun some of this code here comes directly from this project.

Thank you to kclaurelie for helping to solve the fundamental problem that had been bugging me for months!

0.1.0 (2020-10-05)

• First release on PyPI.