Unification

[](https://travis-ci.org/logpy/unification)

Straightforward Unification, extensible via dispatch.

Examples

>>> from unification import *
>>> unify(1, 1)
{}
>>> unify(1, 2)
False
>>> x = var('x')

>>> unify((1, x), (1, 2))
{~x: 2}

>>> unify((x, x), (1, 2))
False

@unifiable
class Account(object):
    def __init__(self, id, name, balance):
        self.id = id
        self.name = name
        self.balance = balance

data = [Account(1, 'Alice', 100),
        Account(2, 'Bob', 0),
        Account(2, 'Charlie', 0),
        Account(2, 'Denis', 400),
        Account(2, 'Edith', 500)]

id, name, balance = var('id'), var('name'), var('balance')

>>> [unify(Account(id, name, balance), acct) for acct in data]
[{~name: 'Alice', ~balance: 100, ~id: 1},
 {~name: 'Bob', ~balance: 0, ~id: 2},
 {~name: 'Charlie', ~balance: 0, ~id: 2},
 {~name: 'Denis', ~balance: 400, ~id: 2},
 {~name: 'Edith', ~balance: 500, ~id: 2}]

>>> [unify(Account(id, name, 0), acct) for acct in data]
[False,
 {~name: 'Bob', ~id: 2},
 {~name: 'Charlie', ~id: 2},
 False,
 False]

History

This was carved out from the LogPy project.

Author

`Matthew Rocklin`_