def get_predicate_arguments(atomspace, predicate_name):
"""
Finds the unique EvaluationLink for a predicate and returns its list
of arguments.
(Adapted from Alex's PLNUnitTester class)
:param atomspace: the atomspace where the predicate should be looked for
:param predicate_name: the name of the predicate
:return: a list of the predicate arguments
"""
chainer = Chainer(atomspace)
var = chainer.new_variable()
predicate = chainer.atomspace.add_node(types.PredicateNode, predicate_name)
template = chainer.link(types.EvaluationLink,
[predicate, var])
queries = chainer.lookup_atoms(template, "")
# The template needs to be removed from the results
queries.remove(template)
if len(queries) != 1:
if predicate_name == "undesired_outputs":
return None
else:
raise ValueError("Predicate {0} must have 1 EvaluationLink"
.format(predicate_name))
return queries[0].out[1].out
def get_predicate_arguments(atomspace, predicate_name):
"""
Finds the unique EvaluationLink for a predicate and returns its list
of arguments.
(Adapted from Alex's PLNUnitTester class)
:param atomspace: the atomspace where the predicate should be looked for
:param predicate_name: the name of the predicate
:return: a list of the predicate arguments
"""
chainer = Chainer(atomspace)
var = chainer.new_variable()
predicate = chainer.atomspace.add_node(types.PredicateNode, predicate_name)
template = chainer.link(types.EvaluationLink, [predicate, var])
queries = chainer.lookup_atoms(template, "")
# The template needs to be removed from the results
queries.remove(template)
if len(queries) != 1:
if predicate_name == "undesired_outputs":
return None
else:
raise ValueError("Predicate {0} must have 1 EvaluationLink".format(
predicate_name))
return queries[0].out[1].out
