def __init__(self, expr, kb=None):
parts = split_on(expr, ':-')
self.head = Term(parts[0], kb=kb)
self.goals = []
if len(parts) == 2:
sub_goals = split_on(parts[1], ',')
for sub_goal in sub_goals:
self.goals.append(Term(sub_goal, kb=kb))
def __init__(self, expr, on_change=None):
parts = split_on(expr, ':-')
self.head = Term(parts[0])
self.goals = []
self.on_change = on_change
self._locked = False
if len(parts) == 2:
context.kb._variable_rules.append(self)
sub_goals = split_on(parts[1], ',')
for sub_goal in sub_goals:
self.goals.append(Term(sub_goal))
def query(self, statement):
"""Query the KB.
:param str statement: A rule to query on.
:return: Generator of alternative bindings to variables that match the query
:Example:
>>> kb = KB()
>>> kb.store('a(a)')
0
>>> kb.query('a(X)') #doctest: +ELLIPSIS
<generator object KB._search at 0x...>
>>> list(kb.query('a(X)'))
[{'X': 'a'}]"""
return self._search(Term(strip_all_whitespace(statement)))
def process(term, bindings, graph=None):
if isAtom(term):
return term
if isVar(term):
ans = bindings.get(term.pred, None)
if not ans:
return None
else:
return process(ans, bindings)
args = []
for arg in term.args:
a = process(arg, bindings)
if not a:
return None
args.append(a)
return Term(term.pred, args)