def execute(self, agent, intention):
# Boolean constants.
term = pyson.evaluate(self.term, intention.scope)
if term is True:
yield
return
elif term is False:
return
try:
group = term.literal_group()
except AttributeError:
raise PysonError(
"expected boolean or literal in query context, got: '%s'" %
term)
# Query on the belief base.
for belief in agent.beliefs[group]:
for _ in pyson.unify_annotated(term, belief, intention.scope,
intention.stack):
yield
choicepoint = object()
# Follow rules.
for rule in agent.rules[group]:
rule = copy.deepcopy(rule)
intention.stack.append(choicepoint)
if pyson.unify(term, rule.head, intention.scope, intention.stack):
for _ in rule.query.execute(agent, intention):
yield
pyson.reroll(intention.scope, intention.stack, choicepoint)
def execute(self, agent, intention):
choicepoint = object()
intention.stack.append(choicepoint)
success = any(True for _ in self.query.execute(agent, intention))
pyson.reroll(intention.scope, intention.stack, choicepoint)
if not success:
yield
def _range_2(agent, term, intention):
choicepoint = object()
for i in range(int(pyson.grounded(term.args[0], intention.scope))):
intention.stack.append(choicepoint)
if pyson.unify(term.args[1], i, intention.scope, intention.stack):
yield
pyson.reroll(intention.scope, intention.stack, choicepoint)
def _member(agent, term, intention):
choicepoint = object()
for member in pyson.evaluate(term.args[1], intention.scope):
intention.stack.append(choicepoint)
if pyson.unify(term.args[0], member, intention.scope, intention.stack):
yield
pyson.reroll(intention.scope, intention.stack, choicepoint)
def _count(agent, term, intention):
query = pyson.runtime.TermQuery(term.args[0])
choicepoint = object()
count = 0
intention.stack.append(choicepoint)
for _ in query.execute(agent, intention):
count += 1
pyson.reroll(intention.scope, intention.stack, choicepoint)
if pyson.unify(count, term.args[1], intention.scope, intention.stack):
yield
def _substring(agent, term, intention):
needle = pyson_str(pyson.grounded(term.args[0], intention.scope))
haystack = pyson_str(pyson.grounded(term.args[1], intention.scope))
choicepoint = object()
pos = haystack.find(needle)
while pos != -1:
intention.stack.append(choicepoint)
if pyson.unify(term.args[2], pos, intention.scope, intention.stack):
yield
pyson.reroll(intention.scope, intention.stack, choicepoint)
pos = haystack.find(needle, pos + 1)
def remove_belief(self, term, intention):
term = pyson.evaluate(term, intention.scope)
try:
group = term.literal_group()
except AttributeError:
raise PysonError("expected belief literal, got: '%s'" % term)
choicepoint = object()
relevant_beliefs = self.beliefs[group]
for belief in relevant_beliefs:
intention.stack.append(choicepoint)
if pyson.unify(term, belief, intention.scope, intention.stack):
relevant_beliefs.remove(belief)
return True
pyson.reroll(intention.scope, intention.stack, choicepoint)
return False
def pop_choicepoint(agent, intention):
choicepoint = intention.choicepoint_stack.pop()
pyson.reroll(intention.scope, intention.stack, choicepoint)
return True
