def __init__(self, ev_context):
super(self.__class__, self).__init__()
self.nodedesc_normalizer = NodeDescriptionNormalizer(
ev_context.corpus_info.feature_types)
self._ev_context = ev_context
for cls in self.constraint_factory:
cls.setup_context(self._ev_context)
self._ntyper = NodeTypeInferencer(ev_context.corpus_info.feature_types)
def __init__(self, ev_context):
super(self.__class__, self).__init__()
self.nodedesc_normalizer = NodeDescriptionNormalizer(ev_context.corpus_info.feature_types)
self._ev_context = ev_context
for cls in self.constraint_factory:
cls.setup_context(self._ev_context)
self._ntyper = NodeTypeInferencer(ev_context.corpus_info.feature_types)
class QueryFactory(ast_visitor.AstVisitor):
"""Creates the internal representation from a query AST.
A query AST is split into three parts:
* node descriptions: a dictionary of `varname: AST`
* predicates: a dictionary with `varname: nltk_contrib.tiger.query.predicates.Predicate` entries
* constraints: a list of ((left, right), nltk_contrib.tiger.query.constraints.Constraint)` tuples
These collections will be used to instantiate a `Query` object.
Anonymous node descriptions will be wrapped into a variable definition with an
automatically generated, globally unique variable name.
"""
get_anon_nodevar = (":anon:%i" % (c, ) for c in count()).next
constraint_factory = ConstraintFactory()
predicate_factory = PredicateFactory()
def __init__(self, ev_context):
super(self.__class__, self).__init__()
self.nodedesc_normalizer = NodeDescriptionNormalizer(
ev_context.corpus_info.feature_types)
self._ev_context = ev_context
for cls in self.constraint_factory:
cls.setup_context(self._ev_context)
self._ntyper = NodeTypeInferencer(ev_context.corpus_info.feature_types)
@ast_visitor.node_handler(ast.NodeDescription)
def handle_node_description(self, child_node):
"""Replaces an anonymous node description with a reference to a fresh node variable.
The node description is stored for later reference.
"""
variable = NodeVariable(self.get_anon_nodevar(), False)
self.node_defs[variable] = child_node
self.node_vars[variable.name] = variable
return self.REPLACE(create_varref(variable.name))
@ast_visitor.node_handler(ast.VariableDefinition)
def handle_node_variable_def(self, child_node):
"""Replaces a node variable definition with a reference, and stores it.
If the variable has already been defined, the node descriptions are merged.
"""
assert child_node.variable.type == ast.VariableTypes.NodeIdentifier
node_variable = NodeVariable.from_node(child_node.variable)
self.node_vars[child_node.variable.name] = node_variable
if node_variable in self.node_defs:
self.node_defs[node_variable] = ast.NodeDescription(
ast.Conjunction([
self.node_defs[node_variable].expression,
child_node.expression.expression
]))
else:
self.node_defs[node_variable] = child_node.expression
return self.REPLACE(
create_varref(child_node.variable.name,
container_type=child_node.variable.container))
@ast_visitor.node_handler(ast.Predicate)
def handle_predicate(self, child_node):
"""Stores the predicate in the list of predicates."""
self.predicates.append(child_node)
return self.CONTINUE(child_node)
@ast_visitor.node_handler(ast.SiblingOperator, ast.CornerOperator,
ast.DominanceOperator, ast.PrecedenceOperator,
ast.SecEdgeOperator)
def constraint_op(self, child_node):
"""Stores the constraint in the list of constraints."""
self.constraints.append(child_node)
return self.CONTINUE(child_node)
def setup(self, query_ast):
"""Creates the collections for the internal representation of the query."""
self.predicates = []
self.node_defs = {}
self.node_vars = {}
self.constraints = []
def _get_variable(self, variable):
"""Returns a node variable object associated with the AST fragment `variable`.
If `variable` is seen the first time, a new node variable is created using
`NodeVariable.from_node`.
"""
try:
return self.node_vars[variable.name]
except KeyError:
node_variable = self.node_vars[
variable.name] = NodeVariable.from_node(variable)
self.node_defs[node_variable] = ast.NodeDescription(ast.Nop())
return node_variable
def _process_predicates(self, predicates):
"""Creates the predicate objects.
The predicate objects are created from the AST nodes using the `predicate_factory`.
"""
for pred_ast_node in self.predicates:
ast_var, predicate = self.predicate_factory.create(pred_ast_node)
predicates[self._get_variable(ast_var)].append(predicate)
def _process_constraints(self, predicates):
"""Creates the constraint objects.
The constraints are created from the AST representations using the `constraint_factory`.
"""
result = []
for constraint_ast_node in self.constraints:
left_var = self._get_variable(
constraint_ast_node.left_operand.variable)
right_var = self._get_variable(
constraint_ast_node.right_operand.variable)
constraint = self.constraint_factory.create(
constraint_ast_node, (left_var.var_type, right_var.var_type),
self._ev_context)
result.append(((left_var, right_var), constraint))
for node_var, var_type in zip(
(left_var, right_var), constraint.get_node_variable_types()):
node_var.refine_type(var_type)
for (left_var, right_var), constraint in result:
left_p, right_p = constraint.get_predicates(left_var, right_var)
predicates[left_var].extend(left_p)
predicates[right_var].extend(right_p)
return result
def _add_type_predicates(self, predicates):
"""Adds type predicates to the predicate lists if necessary.
A type predicate is only added for a node variable if all of the following conditions
are true:
* the node description is empty
* no predicates are defined for the variable
* the variable type is not `NodeType.UNKNOWN`
This mechanism is different from handling of feature records. The type predicate
is added to each disjunct, while the feature record can differ between each disjunct.
"""
for node_variable, description in self.node_defs.iteritems():
if description.expression.TYPE is ast.Nop and len(predicates[node_variable]) == 0 \
and node_variable.var_type is not NodeType.UNKNOWN:
predicates[node_variable].append(
NodeTypePredicate(node_variable.var_type))
def from_ast(self, query_ast):
"""Convert a query AST into a result builder object.
Query ASTs are in the same state as returned by the parser.
The result builder class is injected using the `get_result_builder_class`
on the evaluator context.
"""
return self.run(query_ast)
def result(self, query_ast):
"""Processes the collected items and returns the query object."""
predicates = defaultdict(list)
for node_variable, node_desc in self.node_defs.iteritems():
self.nodedesc_normalizer.run(node_desc)
node_var_type, has_frec = self._ntyper.run(node_desc,
node_variable)
node_variable.refine_type(node_var_type)
if has_frec:
predicates[node_variable].append(
NodeTypePredicate(node_var_type))
self._process_predicates(predicates)
constraints = self._process_constraints(predicates)
self._add_type_predicates(predicates)
return self._ev_context.get_result_builder_class(len(constraints) > 0)(
self._ev_context, self.node_defs, predicates, constraints)
class QueryFactory(ast_visitor.AstVisitor):
"""Creates the internal representation from a query AST.
A query AST is split into three parts:
* node descriptions: a dictionary of `varname: AST`
* predicates: a dictionary with `varname: nltk_contrib.tiger.query.predicates.Predicate` entries
* constraints: a list of ((left, right), nltk_contrib.tiger.query.constraints.Constraint)` tuples
These collections will be used to instantiate a `Query` object.
Anonymous node descriptions will be wrapped into a variable definition with an
automatically generated, globally unique variable name.
"""
get_anon_nodevar = (":anon:%i" % (c, ) for c in count()).next
constraint_factory = ConstraintFactory()
predicate_factory = PredicateFactory()
def __init__(self, ev_context):
super(self.__class__, self).__init__()
self.nodedesc_normalizer = NodeDescriptionNormalizer(ev_context.corpus_info.feature_types)
self._ev_context = ev_context
for cls in self.constraint_factory:
cls.setup_context(self._ev_context)
self._ntyper = NodeTypeInferencer(ev_context.corpus_info.feature_types)
@ast_visitor.node_handler(ast.NodeDescription)
def handle_node_description(self, child_node):
"""Replaces an anonymous node description with a reference to a fresh node variable.
The node description is stored for later reference.
"""
variable = NodeVariable(self.get_anon_nodevar(), False)
self.node_defs[variable] = child_node
self.node_vars[variable.name] = variable
return self.REPLACE(create_varref(variable.name))
@ast_visitor.node_handler(ast.VariableDefinition)
def handle_node_variable_def(self, child_node):
"""Replaces a node variable definition with a reference, and stores it.
If the variable has already been defined, the node descriptions are merged.
"""
assert child_node.variable.type == ast.VariableTypes.NodeIdentifier
node_variable = NodeVariable.from_node(child_node.variable)
self.node_vars[child_node.variable.name] = node_variable
if node_variable in self.node_defs:
self.node_defs[node_variable] = ast.NodeDescription(
ast.Conjunction([self.node_defs[node_variable].expression,
child_node.expression.expression]))
else:
self.node_defs[node_variable] = child_node.expression
return self.REPLACE(create_varref(child_node.variable.name,
container_type = child_node.variable.container))
@ast_visitor.node_handler(ast.Predicate)
def handle_predicate(self, child_node):
"""Stores the predicate in the list of predicates."""
self.predicates.append(child_node)
return self.CONTINUE(child_node)
@ast_visitor.node_handler(ast.SiblingOperator,
ast.CornerOperator,
ast.DominanceOperator,
ast.PrecedenceOperator,
ast.SecEdgeOperator)
def constraint_op(self, child_node):
"""Stores the constraint in the list of constraints."""
self.constraints.append(child_node)
return self.CONTINUE(child_node)
def setup(self, query_ast):
"""Creates the collections for the internal representation of the query."""
self.predicates = []
self.node_defs = {}
self.node_vars = {}
self.constraints = []
def _get_variable(self, variable):
"""Returns a node variable object associated with the AST fragment `variable`.
If `variable` is seen the first time, a new node variable is created using
`NodeVariable.from_node`.
"""
try:
return self.node_vars[variable.name]
except KeyError:
node_variable = self.node_vars[variable.name] = NodeVariable.from_node(variable)
self.node_defs[node_variable] = ast.NodeDescription(ast.Nop())
return node_variable
def _process_predicates(self, predicates):
"""Creates the predicate objects.
The predicate objects are created from the AST nodes using the `predicate_factory`.
"""
for pred_ast_node in self.predicates:
ast_var, predicate = self.predicate_factory.create(pred_ast_node)
predicates[self._get_variable(ast_var)].append(predicate)
def _process_constraints(self, predicates):
"""Creates the constraint objects.
The constraints are created from the AST representations using the `constraint_factory`.
"""
result = []
for constraint_ast_node in self.constraints:
left_var = self._get_variable(constraint_ast_node.left_operand.variable)
right_var = self._get_variable(constraint_ast_node.right_operand.variable)
constraint = self.constraint_factory.create(
constraint_ast_node, (left_var.var_type, right_var.var_type), self._ev_context)
result.append(((left_var, right_var), constraint))
for node_var, var_type in zip((left_var, right_var),
constraint.get_node_variable_types()):
node_var.refine_type(var_type)
for (left_var, right_var), constraint in result:
left_p, right_p = constraint.get_predicates(left_var, right_var)
predicates[left_var].extend(left_p)
predicates[right_var].extend(right_p)
return result
def _add_type_predicates(self, predicates):
"""Adds type predicates to the predicate lists if necessary.
A type predicate is only added for a node variable if all of the following conditions
are true:
* the node description is empty
* no predicates are defined for the variable
* the variable type is not `NodeType.UNKNOWN`
This mechanism is different from handling of feature records. The type predicate
is added to each disjunct, while the feature record can differ between each disjunct.
"""
for node_variable, description in self.node_defs.iteritems():
if description.expression.TYPE is ast.Nop and len(predicates[node_variable]) == 0 \
and node_variable.var_type is not NodeType.UNKNOWN:
predicates[node_variable].append(NodeTypePredicate(node_variable.var_type))
def from_ast(self, query_ast):
"""Convert a query AST into a result builder object.
Query ASTs are in the same state as returned by the parser.
The result builder class is injected using the `get_result_builder_class`
on the evaluator context.
"""
return self.run(query_ast)
def result(self, query_ast):
"""Processes the collected items and returns the query object."""
predicates = defaultdict(list)
for node_variable, node_desc in self.node_defs.iteritems():
self.nodedesc_normalizer.run(node_desc)
node_var_type, has_frec = self._ntyper.run(node_desc, node_variable)
node_variable.refine_type(node_var_type)
if has_frec:
predicates[node_variable].append(NodeTypePredicate(node_var_type))
self._process_predicates(predicates)
constraints = self._process_constraints(predicates)
self._add_type_predicates(predicates)
return self._ev_context.get_result_builder_class(len(constraints) > 0)(
self._ev_context, self.node_defs, predicates, constraints)
