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))
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 _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 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))
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))
def _pad_nodesets(self):
if all(var.is_set for var in self._node_vars):
self._node_cursors.append(
(NodeVariable("", False),
self._query_compiler.get_padding_cursor(), self._node_tips))
