def eq_assoc(u, v, eq=core.eq, n=None):
""" Goal for associative equality
>>> from logpy import run, var, fact
>>> from logpy.assoccomm import eq_assoc as eq
>>> fact(commutative, 'add') # declare that 'add' is commutative
>>> fact(associative, 'add') # declare that 'add' is associative
>>> x = var()
>>> run(0, x, eq(('add', 1, 2, 3), ('add', 1, x)))
(('add', 2, 3),)
"""
op = var()
if isinstance(u, tuple) and isinstance(v, tuple):
return conde([(core.eq, u, v)],
[(heado, op, u), (heado, op, v), (associative, op),
lambda s: assocunify(u, v, s, eq, n)])
if isinstance(u, tuple) or isinstance(v, tuple):
if isinstance(v, tuple):
v, u = u, v
return conde([(core.eq, u, v)],
[(heado, op, u), (associative, op),
lambda s: assocunify(u, v, s, eq, n)])
return (core.eq, u, v)
def eq_assoc(u, v, eq=core.eq, n=None):
""" Goal for associative equality
>>> from logpy import run, var, fact
>>> from logpy.assoccomm import eq_assoc as eq
>>> fact(commutative, 'add') # declare that 'add' is commutative
>>> fact(associative, 'add') # declare that 'add' is associative
>>> x = var()
>>> run(0, x, eq(('add', 1, 2, 3), ('add', 1, x)))
(('add', 2, 3),)
"""
uop, uargs = op_args(u)
vop, vargs = op_args(v)
if uop and vop:
return conde([(core.eq, u, v)],
[(eq, uop, vop), (associative, uop),
lambda s: assocunify(u, v, s, eq, n)])
if uop or vop:
if vop:
uop, vop = vop, uop
uargs, vargs = vargs, uargs
v, u = u, v
return conde([(core.eq, u, v)],
[(associative, uop),
lambda s: assocunify(u, v, s, eq, n)])
return (core.eq, u, v)
def test_run():
x, y, z = map(var, "xyz")
assert run(1, x, eq(x, 1)) == (1,)
assert run(2, x, eq(x, 1)) == (1,)
assert run(0, x, eq(x, 1)) == (1,)
assert run(1, x, eq(x, (y, z)), eq(y, 3), eq(z, 4)) == ((3, 4),)
assert set(run(2, x, conde([eq(x, 1)], [eq(x, 2)]))) == set((1, 2))
def eq_assoccomm(u, v):
""" Associative/Commutative eq
Works like logic.core.eq but supports associative/commutative expr trees
tree-format: (op, *args)
example: (add, 1, 2, 3)
State that operations are associative or commutative with relations
>>> from logpy.assoccomm import eq_assoccomm as eq
>>> from logpy.assoccomm import commutative, associative
>>> from logpy import fact, run, var
>>> fact(commutative, 'add') # declare that 'add' is commutative
>>> x = var
>>> e1 = ('add', 1, 2, 3)
>>> e2 = ('add', 1, x)
>>> run(0, x, eq(e1, e2))
(('add', 2, 3), ('add', 3, 2))
"""
op = var()
return conde(((eq, u, v),),
((opo, u, op), (opo, v, op),
(conde,
((commutative, op), (eq_comm, u, v)),
((associative, op), (eq_assoc, u, v)))))
def test_run():
x, y, z = map(var, 'xyz')
assert run(1, x, eq(x, 1)) == (1, )
assert run(2, x, eq(x, 1)) == (1, )
assert run(0, x, eq(x, 1)) == (1, )
assert run(1, x, eq(x, (y, z)), eq(y, 3), eq(z, 4)) == ((3, 4), )
assert set(run(2, x, conde([eq(x, 1)], [eq(x, 2)]))) == set((1, 2))
def opo(x, op):
""" Operation of a tuple
op((add, 1, 2), x) --> {x: add}
"""
h = var()
return conde(((heado, h, x), (operation, h), (eq, h, op)))
def eq_assoc(u, v, eq=core.eq):
""" Goal for associative equality
>>> from logpy import run, var
>>> from logpy.assoccomm import eq_assoc as eq
>>> fact(commutative, 'add') # declare that 'add' is commutative
>>> fact(associative, 'add') # declare that 'add' is associative
>>> x = var()
>>> run(0, eq(('add', 1, 2, 3), ('add', 1, x)))
(('add', 2, 3),)
"""
op = var()
return conde([(core.eq, u, v)],
[(heado, op, u), (heado, op, v), (associative, op),
lambda s: assocunify(u, v, s, eq)])
def unify_assoccomm(u, v, s, ordering=None):
u = walk(u, s)
v = walk(v, s)
res = unify(u, v, s)
if res is not False:
yield res
if isinstance(u, tuple) and isinstance(v, tuple):
uop, u = u[0], u[1:]
vop, v = v[0], v[1:]
s = unify(uop, vop, s)
if s is False:
raise StopIteration()
op = walk(uop, s)
sm, lg = (u, v) if len(u) <= len(v) else (v, u)
for part in kbins(range(len(lg)), len(sm), ordering):
lg2 = makeops(op, partition(lg, part))
# TODO: we use logpy code within python within logpy
# There must be a more elegant way
for res in conde((eq_assoccomm, a, b) for a, b in zip(sm, lg2))(s):
yield res
def grandparent(x, z):
y = var()
return conde((parent(x, y), parent(y, z)))
def test_conde():
x = var("x")
assert results(conde([eq(x, 2)], [eq(x, 3)])) == ({x: 2}, {x: 3})
assert results(conde([eq(x, 2), eq(x, 3)])) == ()
def test_conde():
x = var('x')
assert tuple(conde([eq(x, 2)], [eq(x, 3)])({})) == ({x: 2}, {x: 3})
assert tuple(conde([eq(x, 2), eq(x, 3)])({})) == ()
def test_conde():
x = var('x')
assert results(conde([eq(x, 2)], [eq(x, 3)])) == ({x: 2}, {x: 3})
assert results(conde([eq(x, 2), eq(x, 3)])) == ()
def operation(op):
""" Either an associative or commutative operation """
return conde([commutative(op)], [associative(op)])
def grandparent(x, z):
y = var()
return conde((parent(x, y), parent(y, z)))
