def __init__(self, compiler, namespace, statement):
State.__init__(self, compiler, namespace, statement)
self._result = None
self._child_statements = {}
self.__attributes = {}
self._refs = {}
self._resolved = False
self._result_ref = ResultVariable(self)
class DynamicState(State):
"""
Represents a dynamic state
"""
def __init__(self, compiler, namespace, statement):
State.__init__(self, compiler, namespace, statement)
self._result = None
self._child_statements = {}
self.__attributes = {}
self._refs = {}
self._resolved = False
self._result_ref = ResultVariable(self)
def add_to_graph(self, graph):
"""
@see State#add_to_graph
This method ensures that the statement can be statically executed,
which means that all types have been resolved.
"""
State.add_to_graph(self, graph)
# make sure all types are resolved
if not State.resolved(self):
# provide a meaningful error
for req_type in self._required_types:
if req_type not in self._resolved_types:
type_name = str(self._required_types[req_type])
raise Exception("Unable to resolve %s for statement %s in file %s:%d" %
(type_name, self.statement, self.statement.filename, self.statement.line))
raise Exception("Unable to resolve all required types")
# get all references this statement needs
for ref_def in self.statement.references():
name = ref_def[0]
value = ref_def[1]
ref_type = "use"
if len(ref_def) > 2:
ref_type = ref_def[2]
if ref_type == "use":
value_ref = get_ref(self, value)
self._refs[name] = value_ref
elif ref_type == "def":
scope = self.get_local_scope()
scope.add_placeholder(name.name)
else:
raise Exception("Unknown ref type given by %s" % self)
# add any statements under this node to the graph as well
self.statement.new_statements(self)
def resolved(self):
"""
Are all dynamic references of this statement resolved?
"""
if self._resolved:
return True
scope = self.get_local_scope()
for ref in self._refs.values():
if not ref.is_available(scope):
return False
self._resolved = True
self.graph.add_actions(self, self.statement.actions(self))
return True
def can_evaluate(self):
"""
Can this statement be evaluated in the current state it is in?
"""
if not self.graph.can_evaluate(self):
return False
return self.statement.can_evaluate(self)
def get_ref(self, name):
"""
Get a reference
"""
reference = self._refs[name]
if reference.__class__ == Reference:
return self.get_local_scope().resolve_reference(reference)
return reference
def get_result(self):
"""
Get the result of evaluating this statement
"""
return self._result
def get_result_reference(self):
"""
This method returns a reference to a result
"""
return self._result_ref
def set_evaluated(self):
"""
Mark this state as evaluated
"""
State.set_evaluated(self)
def evaluate(self):
"""
Evaluate this statement and if successful mark it as evaluated.
@param force: Force the evaluation even if the statement is lazy.
"""
local_scope = self.get_local_scope()
value = self.statement.evaluate(self, local_scope)
if hasattr(value, "_get_instance"):
value = value._get_instance()
if not isinstance(value, Variable):
value = Variable(value)
self._result = value
if self._result is not None:
self._result_ref.value_available()
self.set_evaluated()
def get_state(self, statement):
"""
Get the state of a statement that has been added to the graph by
this state.
"""
if statement in self._child_statements:
return self._child_statements[statement]
raise KeyError()
def add_statement(self, statement, child_ns = False):
"""
Add a new statement that is generated or included by the statement
linked to this state. The new statement is defined in the
same namespace as this statement or in a child namespace.
@param statement: The new statement
@param child_ns: Optional can be set to true to define it in a child
namespace.
"""
if statement in self._child_statements:
raise Exception("Statement %s already added by %s" %
(statement, self))
namespace = self.namespace
if child_ns:
object_id = Scope.object_to_name(self)
namespace = Namespace(object_id, self.namespace)
child_state = DynamicState(self.compiler, namespace, statement)
child_state.add_to_graph(self.graph)
self._child_statements[statement] = child_state
return child_state
def get_attribute(self, name):
"""
Get an attribute that is stored in this state
"""
if name in self.__attributes:
return self.__attributes[name]
raise KeyError(name)
def set_attribute(self, name, value):
"""
Set a value in this state
"""
self.__attributes[name] = value
def has_attribute(self, name):
"""
Is the attribute with name set?
"""
return name in self.__attributes
