def SipStrategy(query,
sipCollection,
factGraph,
derivedPreds,
bindings={},
processedRules=None,
network=None,
debug=False,
buildProof=False,
memoizeMemory=None,
proofLevel=1):
"""
Accordingly, we define a sip-strategy for computing the answers to a query
expressed using a set of Datalog rules, and a set of sips, one for each
adornment of a rule head, as follows...
Each evaluation uses memoization (via Python decorators) but also relies on well-formed
rewrites for using semi-naive bottom up method over large SPARQL data.
"""
memoizeMemory = memoizeMemory and memoizeMemory or {}
queryLiteral = BuildUnitermFromTuple(query)
processedRules = processedRules and processedRules or set()
if bindings:
# There are bindings. Apply them to the terms in the query
queryLiteral.ground(bindings)
if debug:
print("%sSolving" % ('\t' * proofLevel), queryLiteral, bindings)
# Only consider ground triple pattern isomorphism with matching bindings
goalRDFStatement = queryLiteral.toRDFTuple()
if queryLiteral in memoizeMemory:
if debug:
print("%sReturning previously calculated results for " %
('\t' * proofLevel), queryLiteral)
for answers in memoizeMemory[queryLiteral]:
yield answers
elif AlphaNode(goalRDFStatement).alphaNetworkHash(
True,
skolemTerms=list(bindings.values())) in \
[AlphaNode(r.toRDFTuple()).alphaNetworkHash(True,
skolemTerms=list(bindings.values()))
for r in processedRules
if AdornLiteral(goalRDFStatement).adornment ==
r.adornment]:
if debug:
print("%s Goal already processed..." %
('\t' * proofLevel))
else:
isGround = literalIsGround(queryLiteral)
if buildProof:
ns = NodeSet(goalRDFStatement,
network=network, identifier=BNode())
else:
ns = None
# adornedProgram = factGraph.adornedProgram
queryPred = GetOp(queryLiteral)
if sipCollection is None:
rules = []
else:
# For every rule head matching the query, we invoke the rule,
# thus determining an adornment, and selecting a sip to follow
rules = sipCollection.headToRule.get(queryPred, set())
if None in sipCollection.headToRule:
# If there are second order rules, we add them
# since they are a 'wildcard'
rules.update(sipCollection.headToRule[None])
# maintained list of rules that haven't been processed before and
# match the query
validRules = []
# each subquery contains values for the bound arguments that are passed
# through the sip arcs entering the node corresponding to that literal. For
# each subquery generated, there is a set of answers.
answers = []
# variableMapping = {}
# Some TBox queries can be 'joined' together into SPARQL queries against
# 'base' predicates via an RDF dataset
# These atomic concept inclusion axioms can be evaluated together
# using a disjunctive operator at the body of a horn clause
# where each item is a query of the form uniPredicate(?X):
# Or( uniPredicate1(?X1), uniPredicate2(?X), uniPredicate3(?X), ..)
# In this way massive, conjunctive joins can be 'mediated'
# between the stated facts and the top-down solver
@parameterizedPredicate([i for i in derivedPreds])
def IsAtomicInclusionAxiomRHS(rule, dPreds):
"""
This is an atomic inclusion axiom with
a variable (or bound) RHS: uniPred(?ENTITY)
"""
bodyList = list(iterCondition(rule.formula.body))
body = first(bodyList)
return GetOp(body) not in dPreds and \
len(bodyList) == 1 and \
body.op == RDF.type
atomicInclusionAxioms = list(filter(
IsAtomicInclusionAxiomRHS, rules))
if atomicInclusionAxioms and len(atomicInclusionAxioms) > 1:
if debug:
print("\tCombining atomic inclusion axioms: ")
pprint(atomicInclusionAxioms, sys.stderr)
if buildProof:
factStep = InferenceStep(ns, source='some RDF graph')
ns.steps.append(factStep)
axioms = [rule.formula.body
for rule in atomicInclusionAxioms]
# attempt to exaustively apply any available substitutions
# and determine if query if fully ground
vars = [v for v in GetArgs(queryLiteral,
secondOrder=True)
if isinstance(v, Variable)]
openVars, axioms, _bindings = \
normalizeBindingsAndQuery(vars,
bindings,
axioms)
if openVars:
# mappings = {}
# See if we need to do any variable mappings from the query literals
# to the literals in the applicable rules
query, rt = EDBQuery(axioms,
factGraph,
openVars,
_bindings).evaluate(debug,
symmAtomicInclusion=True)
if buildProof:
# FIXME: subquery undefined
factStep.groundQuery = subquery
for ans in rt:
if buildProof:
factStep.bindings.update(ans)
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(ans), ns))
yield ans, ns
else:
# All the relevant derivations have been explored and the result
# is a ground query we can directly execute against the facts
if buildProof:
factStep.bindings.update(bindings)
query, rt = EDBQuery(axioms,
factGraph,
_bindings).evaluate(debug,
symmAtomicInclusion=True)
if buildProof:
# FIXME: subquery undefined
factStep.groundQuery = subquery
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(rt), ns))
yield rt, ns
rules = filter(
lambda i: not IsAtomicInclusionAxiomRHS(i), rules)
for rule in rules:
# An exception is the special predicate ph; it is treated as a base
# predicate and the tuples in it are those supplied for qb by
# unification.
headBindings = getBindingsFromLiteral(
goalRDFStatement, rule.formula.head)
# comboBindings = dict([(k, v) for k, v in itertools.chain(
# bindings.items(),
# headBindings.items())])
varMap = rule.formula.head.getVarMapping(queryLiteral)
if headBindings and\
[term for term in rule.formula.head.getDistinguishedVariables(True)
if varMap.get(term, term) not in headBindings]:
continue
# subQueryAnswers = []
# dontStop = True
# projectedBindings = comboBindings.copy()
if debug:
print("%sProcessing rule" %
('\t' * proofLevel), rule.formula)
if debug and sipCollection:
print(
"Sideways Information Passing (sip) graph for %s: " % queryLiteral)
print(sipCollection.serialize(format='n3'))
for sip in SIPRepresentation(sipCollection):
print(sip)
try:
# Invoke the rule
if buildProof:
step = InferenceStep(ns, rule.formula)
else:
step = None
for rt, step in\
invokeRule([headBindings],
iter(iterCondition(rule.formula.body)),
rule.sip,
(proofLevel + 1,
memoizeMemory,
sipCollection,
factGraph,
derivedPreds,
processedRules.union([
AdornLiteral(query)])),
step=step,
debug=debug):
if rt:
if isinstance(rt, dict):
# We received a mapping and must rewrite it via
# correlation between the variables in the rule head
# and the variables in the original query (after applying
# bindings)
varMap = rule.formula.head.getVarMapping(
queryLiteral)
if varMap:
rt = MakeImmutableDict(
refactorMapping(varMap, rt))
if buildProof:
step.bindings = rt
else:
if buildProof:
step.bindings = headBindings
validRules.append(rule)
if buildProof:
ns.steps.append(step)
if isGround:
yield True, ns
else:
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(rt),
ns))
yield rt, ns
except RuleFailure:
# Clean up failed antecedents
if buildProof:
if ns in step.antecedents:
step.antecedents.remove(ns)
if not validRules:
# No rules matching, query factGraph for answers
successful = False
if buildProof:
factStep = InferenceStep(ns, source='some RDF graph')
ns.steps.append(factStep)
if not isGround:
subquery, rt = EDBQuery([queryLiteral],
factGraph,
[v for v in GetArgs(queryLiteral,
secondOrder=True)
if isinstance(v, Variable)],
bindings).evaluate(debug)
if buildProof:
factStep.groundQuery = subquery
for ans in rt:
successful = True
if buildProof:
factStep.bindings.update(ans)
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(ans),
ns))
yield ans, ns
if not successful and queryPred not in derivedPreds:
# Open query didn't return any results and the predicate
# is ostensibly marked as derived predicate, so we have
# failed
memoizeMemory.setdefault(
queryLiteral, set()).add((False, ns))
yield False, ns
else:
# All the relevant derivations have been explored and the result
# is a ground query we can directly execute against the facts
if buildProof:
factStep.bindings.update(bindings)
subquery, rt = EDBQuery([queryLiteral],
factGraph,
bindings).evaluate(debug)
if buildProof:
factStep.groundQuery = subquery
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(rt),
ns))
yield rt, ns
def SipStrategy(query,
sipCollection,
factGraph,
derivedPreds,
bindings={},
processedRules=None,
network=None,
debug=False,
buildProof=False,
memoizeMemory=None,
proofLevel=1):
"""
Accordingly, we define a sip-strategy for computing the answers to a query
expressed using a set of Datalog rules, and a set of sips, one for each
adornment of a rule head, as follows...
Each evaluation uses memoization (via Python decorators) but also relies on well-formed
rewrites for using semi-naive bottom up method over large SPARQL data.
"""
memoizeMemory = memoizeMemory and memoizeMemory or {}
queryLiteral = BuildUnitermFromTuple(query)
processedRules = processedRules and processedRules or set()
if bindings:
#There are bindings. Apply them to the terms in the query
queryLiteral.ground(bindings)
if debug:
print("%sSolving" % ('\t' * proofLevel), queryLiteral, bindings)
# Only consider ground triple pattern isomorphism with matching bindings
goalRDFStatement = queryLiteral.toRDFTuple()
if queryLiteral in memoizeMemory:
if debug:
print("%sReturning previously calculated results for " % \
('\t' * proofLevel), queryLiteral)
for answers in memoizeMemory[queryLiteral]:
yield answers
elif AlphaNode(goalRDFStatement).alphaNetworkHash(
True,
skolemTerms=list(bindings.values())) in \
[AlphaNode(r.toRDFTuple()).alphaNetworkHash(True,
skolemTerms=list(bindings.values()))
for r in processedRules
if AdornLiteral(goalRDFStatement).adornment == \
r.adornment]:
if debug:
print("%s Goal already processed..." % \
('\t' * proofLevel))
else:
isGround = literalIsGround(queryLiteral)
if buildProof:
ns = NodeSet(goalRDFStatement, network=network, identifier=BNode())
else:
ns = None
# adornedProgram = factGraph.adornedProgram
queryPred = GetOp(queryLiteral)
if sipCollection is None:
rules = []
else:
#For every rule head matching the query, we invoke the rule,
#thus determining an adornment, and selecting a sip to follow
rules = sipCollection.headToRule.get(queryPred, set())
if None in sipCollection.headToRule:
#If there are second order rules, we add them
#since they are a 'wildcard'
rules.update(sipCollection.headToRule[None])
#maintained list of rules that haven't been processed before and
#match the query
validRules = []
#each subquery contains values for the bound arguments that are passed
#through the sip arcs entering the node corresponding to that literal. For
#each subquery generated, there is a set of answers.
answers = []
# variableMapping = {}
#Some TBox queries can be 'joined' together into SPARQL queries against
#'base' predicates via an RDF dataset
#These atomic concept inclusion axioms can be evaluated together
#using a disjunctive operator at the body of a horn clause
#where each item is a query of the form uniPredicate(?X):
#Or( uniPredicate1(?X1), uniPredicate2(?X), uniPredicate3(?X), ..)
#In this way massive, conjunctive joins can be 'mediated'
#between the stated facts and the top-down solver
@parameterizedPredicate([i for i in derivedPreds])
def IsAtomicInclusionAxiomRHS(rule, dPreds):
"""
This is an atomic inclusion axiom with
a variable (or bound) RHS: uniPred(?ENTITY)
"""
bodyList = list(iterCondition(rule.formula.body))
body = first(bodyList)
return GetOp(body) not in dPreds and \
len(bodyList) == 1 and \
body.op == RDF.type
atomicInclusionAxioms = list(filter(IsAtomicInclusionAxiomRHS, rules))
if atomicInclusionAxioms and len(atomicInclusionAxioms) > 1:
if debug:
print("\tCombining atomic inclusion axioms: ")
pprint(atomicInclusionAxioms, sys.stderr)
if buildProof:
factStep = InferenceStep(ns, source='some RDF graph')
ns.steps.append(factStep)
axioms = [rule.formula.body for rule in atomicInclusionAxioms]
#attempt to exaustively apply any available substitutions
#and determine if query if fully ground
vars = [
v for v in GetArgs(queryLiteral, secondOrder=True)
if isinstance(v, Variable)
]
openVars, axioms, _bindings = \
normalizeBindingsAndQuery(vars,
bindings,
axioms)
if openVars:
# mappings = {}
#See if we need to do any variable mappings from the query literals
#to the literals in the applicable rules
query, rt = EDBQuery(axioms, factGraph, openVars,
_bindings).evaluate(
debug, symmAtomicInclusion=True)
if buildProof:
factStep.groundQuery = subquery
for ans in rt:
if buildProof:
factStep.bindings.update(ans)
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(ans), ns))
yield ans, ns
else:
#All the relevant derivations have been explored and the result
#is a ground query we can directly execute against the facts
if buildProof:
factStep.bindings.update(bindings)
query, rt = EDBQuery(axioms, factGraph, _bindings).evaluate(
debug, symmAtomicInclusion=True)
if buildProof:
factStep.groundQuery = subquery
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(rt), ns))
yield rt, ns
rules = filter(lambda i: not IsAtomicInclusionAxiomRHS(i), rules)
for rule in rules:
#An exception is the special predicate ph; it is treated as a base
#predicate and the tuples in it are those supplied for qb by unification.
headBindings = getBindingsFromLiteral(goalRDFStatement,
rule.formula.head)
# comboBindings = dict([(k, v) for k, v in itertools.chain(
# bindings.items(),
# headBindings.items())])
varMap = rule.formula.head.getVarMapping(queryLiteral)
if headBindings and\
[term for term in rule.formula.head.getDistinguishedVariables(True)
if varMap.get(term, term) not in headBindings]:
continue
# subQueryAnswers = []
# dontStop = True
# projectedBindings = comboBindings.copy()
if debug:
print("%sProcessing rule" % \
('\t' * proofLevel), rule.formula)
if debug and sipCollection:
print("Sideways Information Passing (sip) graph for %s: " %
queryLiteral)
print(sipCollection.serialize(format='n3'))
for sip in SIPRepresentation(sipCollection):
print(sip)
try:
# Invoke the rule
if buildProof:
step = InferenceStep(ns, rule.formula)
else:
step = None
for rt, step in\
invokeRule([headBindings],
iter(iterCondition(rule.formula.body)),
rule.sip,
(proofLevel + 1,
memoizeMemory,
sipCollection,
factGraph,
derivedPreds,
processedRules.union([
AdornLiteral(query)])),
step=step,
debug=debug):
if rt:
if isinstance(rt, dict):
#We received a mapping and must rewrite it via
#correlation between the variables in the rule head
#and the variables in the original query (after applying
#bindings)
varMap = rule.formula.head.getVarMapping(
queryLiteral)
if varMap:
rt = MakeImmutableDict(
refactorMapping(varMap, rt))
if buildProof:
step.bindings = rt
else:
if buildProof:
step.bindings = headBindings
validRules.append(rule)
if buildProof:
ns.steps.append(step)
if isGround:
yield True, ns
else:
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(rt), ns))
yield rt, ns
except RuleFailure:
# Clean up failed antecedents
if buildProof:
if ns in step.antecedents:
step.antecedents.remove(ns)
if not validRules:
#No rules matching, query factGraph for answers
successful = False
if buildProof:
factStep = InferenceStep(ns, source='some RDF graph')
ns.steps.append(factStep)
if not isGround:
subquery, rt = EDBQuery([queryLiteral], factGraph, [
v for v in GetArgs(queryLiteral, secondOrder=True)
if isinstance(v, Variable)
], bindings).evaluate(debug)
if buildProof:
factStep.groundQuery = subquery
for ans in rt:
successful = True
if buildProof:
factStep.bindings.update(ans)
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(ans), ns))
yield ans, ns
if not successful and queryPred not in derivedPreds:
#Open query didn't return any results and the predicate
#is ostensibly marked as derived predicate, so we have failed
memoizeMemory.setdefault(queryLiteral, set()).add(
(False, ns))
yield False, ns
else:
#All the relevant derivations have been explored and the result
#is a ground query we can directly execute against the facts
if buildProof:
factStep.bindings.update(bindings)
subquery, rt = EDBQuery([queryLiteral], factGraph,
bindings).evaluate(debug)
if buildProof:
factStep.groundQuery = subquery
memoizeMemory.setdefault(queryLiteral, set()).add(
(prepMemiozedAns(rt), ns))
yield rt, ns
def invokeRule(priorAnswers,
bodyLiteralIterator,
sip,
otherargs,
priorBooleanGoalSuccess=False,
step=None,
debug=False,
buildProof=False):
"""
Continue invokation of rule using (given) prior answers and list of
remaining body literals (& rule sip). If prior answers is a list,
computation is split disjunctively
[..] By combining the answers to all these subqueries, we generate
answers for the original query involving the rule head
Can also takes a PML step and updates it as it navigates the
top-down proof tree (passing it on and updating it where necessary)
"""
assert not buildProof or step is not None
proofLevel, memoizeMemory, sipCollection, \
factGraph, derivedPreds, processedRules = otherargs
remainingBodyList = [i for i in bodyLiteralIterator]
lazyGenerator = lazyGeneratorPeek(priorAnswers, 2)
if lazyGenerator.successful:
# There are multiple answers in this step, we need to call invokeRule
# recursively for each answer, returning the first positive attempt
success = False
rt = None
_step = None
ansNo = 0
for priorAns in lazyGenerator:
ansNo += 1
try:
if buildProof:
newStep = InferenceStep(step.parent,
step.rule,
source=step.source)
newStep.antecedents = [ant for ant in step.antecedents]
else:
newStep = None
for rt, _step in\
invokeRule([priorAns],
iter([i for i in remainingBodyList]),
sip,
otherargs,
priorBooleanGoalSuccess,
newStep,
debug=debug,
buildProof=buildProof):
if rt:
yield rt, _step
except RuleFailure:
pass
if not success:
# None of prior answers were successful
# indicate termination of rule processing
raise RuleFailure(
"Unable to solve either of %s against remainder of rule: %s" % (
ansNo, remainingBodyList))
# yield False, _InferenceStep(step.parent, step.rule,
# source=step.source)
else:
lazyGenerator = lazyGeneratorPeek(lazyGenerator)
projectedBindings = lazyGenerator.successful and first(
lazyGenerator) or {}
# First we check if we can combine a large group of subsequent body literals
# into a single query
# if we have a template map then we use it to further
# distinguish which builtins can be solved via
# cumulative SPARQl query - else we solve
# builtins one at a time
def sparqlResolvable(literal):
if isinstance(literal, Uniterm):
return not literal.naf and GetOp(literal) not in derivedPreds
else:
return isinstance(literal, N3Builtin) and \
literal.uri in factGraph.templateMap
def sparqlResolvableNoTemplates(literal):
if isinstance(literal, Uniterm):
return not literal.naf and GetOp(literal) not in derivedPreds
else:
return False
conjGroundLiterals = list(
itertools.takewhile(
hasattr(factGraph, 'templateMap') and sparqlResolvable or
sparqlResolvableNoTemplates,
remainingBodyList))
bodyLiteralIterator = iter(remainingBodyList)
if len(conjGroundLiterals) > 1:
# If there are literals to combine *and* a mapping from rule
# builtins to SPARQL FILTER templates ..
basePredicateVars = set(
reduce(lambda x, y: x + y,
[list(GetVariables(arg, secondOrder=True)) for arg in conjGroundLiterals]))
if projectedBindings:
openVars = basePredicateVars.intersection(projectedBindings)
else:
# We don't have any given bindings, so we need to treat
# the body as an open query
openVars = basePredicateVars
queryConj = EDBQuery([copy.deepcopy(lit) for lit in conjGroundLiterals],
factGraph,
openVars,
projectedBindings)
query, answers = queryConj.evaluate(debug)
if isinstance(answers, bool):
combinedAnswers = {}
rtCheck = answers
else:
if projectedBindings:
combinedAnswers = (mergeMappings1To2(ans,
projectedBindings,
makeImmutable=True) for ans in answers)
else:
combinedAnswers = (MakeImmutableDict(ans)
for ans in answers)
combinedAnsLazyGenerator = lazyGeneratorPeek(combinedAnswers)
rtCheck = combinedAnsLazyGenerator.successful
if not rtCheck:
raise RuleFailure(
"No answers for combined SPARQL query: %s" % query)
else:
# We have solved the previous N body literals with a single
# conjunctive query, now we need to make each of the literals
# an antecedent to a 'query' step.
if buildProof:
queryStep = InferenceStep(None, source='some RDF graph')
# FIXME: subquery undefined
queryStep.groundQuery = subquery
queryStep.bindings = {} # combinedAnswers[-1]
# FIXME: subquery undefined
queryHash = URIRef(
"tag:[email protected]:Queries#" +
makeMD5Digest(subquery))
queryStep.identifier = queryHash
for subGoal in conjGroundLiterals:
subNs = NodeSet(subGoal.toRDFTuple(),
identifier=BNode())
subNs.steps.append(queryStep)
step.antecedents.append(subNs)
queryStep.parent = subNs
for rt, _step in invokeRule(
isinstance(answers, bool) and [
projectedBindings] or combinedAnsLazyGenerator,
iter(remainingBodyList[len(conjGroundLiterals):]),
sip,
otherargs,
isinstance(answers, bool),
step,
debug=debug,
buildProof=buildProof):
yield rt, _step
else:
# Continue processing rule body condition
# one literal at a time
try:
bodyLiteral = next(
bodyLiteralIterator) if py3compat.PY3 else bodyLiteralIterator.next()
# if a N3 builtin, execute it using given bindings for boolean answer
# builtins are moved to end of rule when evaluating rules via
# sip
if isinstance(bodyLiteral, N3Builtin):
lhs = bodyLiteral.argument
rhs = bodyLiteral.result
lhs = isinstance(
lhs, Variable) and projectedBindings[lhs] or lhs
rhs = isinstance(
rhs, Variable) and projectedBindings[rhs] or rhs
assert lhs is not None and rhs is not None
if bodyLiteral.func(lhs, rhs):
if debug:
print("Invoked %s(%s, %s) -> True" % (
bodyLiteral.uri, lhs, rhs))
# positive answer means we can continue processing the
# rule body
if buildProof:
ns = NodeSet(bodyLiteral.toRDFTuple(),
identifier=BNode())
step.antecedents.append(ns)
for rt, _step in invokeRule(
[projectedBindings],
bodyLiteralIterator,
sip,
otherargs,
step,
priorBooleanGoalSuccess,
debug=debug,
buildProof=buildProof):
yield rt, _step
else:
if debug:
print("Successfully invoked %s(%s, %s) -> False" % (
bodyLiteral.uri, lhs, rhs))
raise RuleFailure("Failed builtin invokation %s(%s, %s)" %
(bodyLiteral.uri, lhs, rhs))
else:
# For every body literal, subqueries are generated according
# to the sip
sipArcPred = URIRef(GetOp(bodyLiteral) +
'_' + '_'.join(GetArgs(bodyLiteral)))
assert len(list(IncomingSIPArcs(sip, sipArcPred))) < 2
subquery = copy.deepcopy(bodyLiteral)
subquery.ground(projectedBindings)
for N, x in IncomingSIPArcs(sip, sipArcPred):
# That is, each subquery contains values for the bound arguments
# that are passed through the sip arcs entering the node
# corresponding to that literal
# Create query out of body literal and apply
# sip-provided bindings
subquery = copy.deepcopy(bodyLiteral)
subquery.ground(projectedBindings)
if literalIsGround(subquery):
# subquery is ground, so there will only be boolean answers
# we return the conjunction of the answers for the current
# subquery
answer = False
ns = None
answers = first(
itertools.dropwhile(
lambda item: not item[0],
SipStrategy(
subquery.toRDFTuple(),
sipCollection,
factGraph,
derivedPreds,
MakeImmutableDict(projectedBindings),
processedRules,
network=step is not None and
step.parent.network or None,
debug=debug,
buildProof=buildProof,
memoizeMemory=memoizeMemory,
proofLevel=proofLevel)))
if answers:
answer, ns = answers
if not answer and not bodyLiteral.naf or \
(answer and bodyLiteral.naf):
# negative answer means the invokation of the rule fails
# either because we have a positive literal and there
# is no answer for the subgoal or the literal is
# negative and there is an answer for the subgoal
raise RuleFailure(
"No solutions solving ground query %s" % subquery)
else:
if buildProof:
if not answer and bodyLiteral.naf:
ns.naf = True
step.antecedents.append(ns)
# positive answer means we can continue processing the rule body
# either because we have a positive literal and answers
# for subgoal or a negative literal and no answers for the
# the goal
for rt, _step in invokeRule(
[projectedBindings],
bodyLiteralIterator,
sip,
otherargs,
True,
step,
debug=debug):
yield rt, _step
else:
_answers = \
SipStrategy(
subquery.toRDFTuple(),
sipCollection,
factGraph,
derivedPreds,
MakeImmutableDict(
projectedBindings),
processedRules,
network=step is not None and
step.parent.network or None,
debug=debug,
buildProof=buildProof,
memoizeMemory=memoizeMemory,
proofLevel=proofLevel)
# solve (non-ground) subgoal
def collectAnswers(_ans):
for ans, ns in _ans:
if isinstance(ans, dict):
try:
map = mergeMappings1To2(
ans, projectedBindings,
makeImmutable=True)
yield map
except:
pass
combinedAnswers = collectAnswers(_answers)
answers = lazyGeneratorPeek(combinedAnswers)
if not answers.successful \
and not bodyLiteral.naf \
or (bodyLiteral.naf and answers.successful):
raise RuleFailure(
"No solutions solving ground query %s" % subquery)
else:
# Either we have a positive subgoal and answers
# or a negative subgoal and no answers
if buildProof:
if answers.successful:
goals = set([g for a, g in answers])
assert len(goals) == 1
step.antecedents.append(goals.pop())
else:
newNs = NodeSet(
bodyLiteral.toRDFTuple(),
network=step.parent.network,
identifier=BNode(),
naf=True)
step.antecedents.append(newNs)
for rt, _step in invokeRule(
answers,
bodyLiteralIterator,
sip,
otherargs,
priorBooleanGoalSuccess,
step,
debug=debug,
buildProof=buildProof):
yield rt, _step
except StopIteration:
# Finished processing rule
if priorBooleanGoalSuccess:
yield projectedBindings and projectedBindings or True, step
elif projectedBindings:
# Return the most recent (cumulative) answers and the given
# step
yield projectedBindings, step
else:
raise RuleFailure(
"Finished processing rule unsuccessfully")
def invokeRule(priorAnswers,
bodyLiteralIterator,
sip,
otherargs,
priorBooleanGoalSuccess=False,
step=None,
debug=False,
buildProof=False):
"""
Continue invokation of rule using (given) prior answers and list of
remaining body literals (& rule sip). If prior answers is a list,
computation is split disjunctively
[..] By combining the answers to all these subqueries, we generate
answers for the original query involving the rule head
Can also takes a PML step and updates it as it navigates the
top-down proof tree (passing it on and updating it where necessary)
"""
assert not buildProof or step is not None
proofLevel, memoizeMemory, sipCollection, \
factGraph, derivedPreds, processedRules = otherargs
remainingBodyList = [i for i in bodyLiteralIterator]
lazyGenerator = lazyGeneratorPeek(priorAnswers, 2)
if lazyGenerator.successful:
# There are multiple answers in this step, we need to call invokeRule
# recursively for each answer, returning the first positive attempt
success = False
rt = None
_step = None
ansNo = 0
for priorAns in lazyGenerator:
ansNo += 1
try:
if buildProof:
newStep = InferenceStep(step.parent,
step.rule,
source=step.source)
newStep.antecedents = [ant for ant in step.antecedents]
else:
newStep = None
for rt, _step in\
invokeRule([priorAns],
iter([i for i in remainingBodyList]),
sip,
otherargs,
priorBooleanGoalSuccess,
newStep,
debug=debug,
buildProof=buildProof):
if rt:
yield rt, _step
except RuleFailure:
pass
if not success:
# None of prior answers were successful
# indicate termination of rule processing
raise RuleFailure(
"Unable to solve either of %s against remainder of rule: %s" %
(ansNo, remainingBodyList))
# yield False, _InferenceStep(step.parent, step.rule, source=step.source)
else:
lazyGenerator = lazyGeneratorPeek(lazyGenerator)
projectedBindings = lazyGenerator.successful and first(
lazyGenerator) or {}
# First we check if we can combine a large group of subsequent body literals
# into a single query
# if we have a template map then we use it to further
# distinguish which builtins can be solved via
# cumulative SPARQl query - else we solve
# builtins one at a time
def sparqlResolvable(literal):
if isinstance(literal, Uniterm):
return not literal.naf and GetOp(literal) not in derivedPreds
else:
return isinstance(literal, N3Builtin) and \
literal.uri in factGraph.templateMap
def sparqlResolvableNoTemplates(literal):
if isinstance(literal, Uniterm):
return not literal.naf and GetOp(literal) not in derivedPreds
else:
return False
conjGroundLiterals = list(
itertools.takewhile(
hasattr(factGraph, 'templateMap') and sparqlResolvable or \
sparqlResolvableNoTemplates,
remainingBodyList))
bodyLiteralIterator = iter(remainingBodyList)
if len(conjGroundLiterals) > 1:
# If there are literals to combine *and* a mapping from rule
# builtins to SPARQL FILTER templates ..
basePredicateVars = set(
reduce(lambda x, y: x + y, [
list(GetVariables(arg, secondOrder=True))
for arg in conjGroundLiterals
]))
if projectedBindings:
openVars = basePredicateVars.intersection(projectedBindings)
else:
# We don't have any given bindings, so we need to treat
# the body as an open query
openVars = basePredicateVars
queryConj = EDBQuery(
[copy.deepcopy(lit) for lit in conjGroundLiterals], factGraph,
openVars, projectedBindings)
query, answers = queryConj.evaluate(debug)
if isinstance(answers, bool):
combinedAnswers = {}
rtCheck = answers
else:
if projectedBindings:
combinedAnswers = (mergeMappings1To2(ans,
projectedBindings,
makeImmutable=True)
for ans in answers)
else:
combinedAnswers = (MakeImmutableDict(ans)
for ans in answers)
combinedAnsLazyGenerator = lazyGeneratorPeek(combinedAnswers)
rtCheck = combinedAnsLazyGenerator.successful
if not rtCheck:
raise RuleFailure("No answers for combined SPARQL query: %s" %
query)
else:
# We have solved the previous N body literals with a single
# conjunctive query, now we need to make each of the literals
# an antecedent to a 'query' step.
if buildProof:
queryStep = InferenceStep(None, source='some RDF graph')
queryStep.groundQuery = subquery
queryStep.bindings = {} # combinedAnswers[-1]
queryHash = URIRef(
"tag:[email protected]:Queries#" + \
makeMD5Digest(subquery))
queryStep.identifier = queryHash
for subGoal in conjGroundLiterals:
subNs = NodeSet(subGoal.toRDFTuple(),
identifier=BNode())
subNs.steps.append(queryStep)
step.antecedents.append(subNs)
queryStep.parent = subNs
for rt, _step in invokeRule(
isinstance(answers, bool) and [projectedBindings]
or combinedAnsLazyGenerator,
iter(remainingBodyList[len(conjGroundLiterals):]),
sip,
otherargs,
isinstance(answers, bool),
step,
debug=debug,
buildProof=buildProof):
yield rt, _step
else:
# Continue processing rule body condition
# one literal at a time
try:
bodyLiteral = next(
bodyLiteralIterator
) if py3compat.PY3 else bodyLiteralIterator.next()
# if a N3 builtin, execute it using given bindings for boolean answer
# builtins are moved to end of rule when evaluating rules via sip
if isinstance(bodyLiteral, N3Builtin):
lhs = bodyLiteral.argument
rhs = bodyLiteral.result
lhs = isinstance(
lhs, Variable) and projectedBindings[lhs] or lhs
rhs = isinstance(
rhs, Variable) and projectedBindings[rhs] or rhs
assert lhs is not None and rhs is not None
if bodyLiteral.func(lhs, rhs):
if debug:
print("Invoked %s(%s, %s) -> True" %
(bodyLiteral.uri, lhs, rhs))
# positive answer means we can continue processing the rule body
if buildProof:
ns = NodeSet(bodyLiteral.toRDFTuple(),
identifier=BNode())
step.antecedents.append(ns)
for rt, _step in invokeRule([projectedBindings],
bodyLiteralIterator,
sip,
otherargs,
step,
priorBooleanGoalSuccess,
debug=debug,
buildProof=buildProof):
yield rt, _step
else:
if debug:
print("Successfully invoked %s(%s, %s) -> False" %
(bodyLiteral.uri, lhs, rhs))
raise RuleFailure(
"Failed builtin invokation %s(%s, %s)" %
(bodyLiteral.uri, lhs, rhs))
else:
# For every body literal, subqueries are generated according
# to the sip
sipArcPred = URIRef(GetOp(bodyLiteral) + \
'_' + '_'.join(GetArgs(bodyLiteral)))
assert len(list(IncomingSIPArcs(sip, sipArcPred))) < 2
subquery = copy.deepcopy(bodyLiteral)
subquery.ground(projectedBindings)
for N, x in IncomingSIPArcs(sip, sipArcPred):
#That is, each subquery contains values for the bound arguments
#that are passed through the sip arcs entering the node
#corresponding to that literal
#Create query out of body literal and apply sip-provided bindings
subquery = copy.deepcopy(bodyLiteral)
subquery.ground(projectedBindings)
if literalIsGround(subquery):
#subquery is ground, so there will only be boolean answers
#we return the conjunction of the answers for the current
#subquery
answer = False
ns = None
answers = first(
itertools.dropwhile(
lambda item: not item[0],
SipStrategy(
subquery.toRDFTuple(),
sipCollection,
factGraph,
derivedPreds,
MakeImmutableDict(projectedBindings),
processedRules,
network=step is not None and \
step.parent.network or None,
debug=debug,
buildProof=buildProof,
memoizeMemory=memoizeMemory,
proofLevel=proofLevel)))
if answers:
answer, ns = answers
if not answer and not bodyLiteral.naf or \
(answer and bodyLiteral.naf):
#negative answer means the invokation of the rule fails
#either because we have a positive literal and there
#is no answer for the subgoal or the literal is
#negative and there is an answer for the subgoal
raise RuleFailure(
"No solutions solving ground query %s" %
subquery)
else:
if buildProof:
if not answer and bodyLiteral.naf:
ns.naf = True
step.antecedents.append(ns)
#positive answer means we can continue processing the rule body
#either because we have a positive literal and answers
#for subgoal or a negative literal and no answers for the
#the goal
for rt, _step in invokeRule([projectedBindings],
bodyLiteralIterator,
sip,
otherargs,
True,
step,
debug=debug):
yield rt, _step
else:
_answers = \
SipStrategy(subquery.toRDFTuple(),
sipCollection,
factGraph,
derivedPreds,
MakeImmutableDict(projectedBindings),
processedRules,
network=step is not None and \
step.parent.network or None,
debug=debug,
buildProof=buildProof,
memoizeMemory=memoizeMemory,
proofLevel=proofLevel)
# solve (non-ground) subgoal
def collectAnswers(_ans):
for ans, ns in _ans:
if isinstance(ans, dict):
try:
map = mergeMappings1To2(
ans,
projectedBindings,
makeImmutable=True)
yield map
except:
pass
combinedAnswers = collectAnswers(_answers)
answers = lazyGeneratorPeek(combinedAnswers)
if not answers.successful \
and not bodyLiteral.naf \
or (bodyLiteral.naf and answers.successful):
raise RuleFailure(
"No solutions solving ground query %s" %
subquery)
else:
# Either we have a positive subgoal and answers
# or a negative subgoal and no answers
if buildProof:
if answers.successful:
goals = set([g for a, g in answers])
assert len(goals) == 1
step.antecedents.append(goals.pop())
else:
newNs = NodeSet(
bodyLiteral.toRDFTuple(),
network=step.parent.network,
identifier=BNode(),
naf=True)
step.antecedents.append(newNs)
for rt, _step in invokeRule(
answers,
bodyLiteralIterator,
sip,
otherargs,
priorBooleanGoalSuccess,
step,
debug=debug,
buildProof=buildProof):
yield rt, _step
except StopIteration:
#Finished processing rule
if priorBooleanGoalSuccess:
yield projectedBindings and projectedBindings or True, step
elif projectedBindings:
#Return the most recent (cumulative) answers and the given step
yield projectedBindings, step
else:
raise RuleFailure(
"Finished processing rule unsuccessfully")
