def reify(e, s):
if isvar(e):
return walkstar(e, s)
elif isinstance(e, tuple):
return tuple(reify(arg, s) for arg in e)
else:
return e
def run(n, x, *goals):
""" Run a logic program. Obtain n solutions to satisfy goals.
n - number of desired solutions. See ``take``
0 for all
None for a lazy sequence
x - Output variable
goals - a sequence of goals. All must be true
>>> from logpy import run, var, eq
>>> run(1, x, eq(x, 1))
(1,)
"""
return take(n, unique(walkstar(x, s) for s in bindstar(({},), *goals)))
def reify(e, s):
""" Replace variables of expression with substitution
>>> e = (1, x, (3, y))
>>> s = {x: 2, y: 4}
>>> reify(e, s)
(1, 2, (3, 4))
"""
if isvar(e):
return walkstar(e, s)
elif isinstance(e, tuple):
return tuple(reify(arg, s) for arg in e)
else:
return e
