Example of refactoring using rope library.

tools/telemetry/third_party/rope/rope/refactor/localtofield.py

Index: tools/telemetry/third_party/rope/rope/refactor/localtofield.py
diff --git a/tools/telemetry/third_party/rope/rope/refactor/localtofield.py b/tools/telemetry/third_party/rope/rope/refactor/localtofield.py
new file mode 100644
index 0000000000000000000000000000000000000000..f276070f71fab99a7efadeed8e91c2437c201328
--- /dev/null
+++ b/tools/telemetry/third_party/rope/rope/refactor/localtofield.py
@@ -0,0 +1,49 @@
+from rope.base import pynames, evaluate, exceptions, worder
+from rope.refactor.rename import Rename
+
+
+class LocalToField(object):
+
+    def __init__(self, project, resource, offset):
+        self.project = project
+        self.resource = resource
+        self.offset = offset
+
+    def get_changes(self):
+        name = worder.get_name_at(self.resource, self.offset)
+        this_pymodule = self.project.get_pymodule(self.resource)
+        pyname = evaluate.eval_location(this_pymodule, self.offset)
+        if not self._is_a_method_local(pyname):
+            raise exceptions.RefactoringError(
+                'Convert local variable to field should be performed on \n'
+                'a local variable of a method.')
+
+        pymodule, lineno = pyname.get_definition_location()
+        function_scope = pymodule.get_scope().get_inner_scope_for_line(lineno)
+        # Not checking redefinition
+        #self._check_redefinition(name, function_scope)
+
+        new_name = self._get_field_name(function_scope.pyobject, name)
+        changes = Rename(self.project, self.resource, self.offset).\
+            get_changes(new_name, resources=[self.resource])
+        return changes
+
+    def _check_redefinition(self, name, function_scope):
+        class_scope = function_scope.parent
+        if name in class_scope.pyobject:
+            raise exceptions.RefactoringError(
+                'The field %s already exists' % name)
+
+    def _get_field_name(self, pyfunction, name):
+        self_name = pyfunction.get_param_names()[0]
+        new_name = self_name + '.' + name
+        return new_name
+
+    def _is_a_method_local(self, pyname):
+        pymodule, lineno = pyname.get_definition_location()
+        holding_scope = pymodule.get_scope().get_inner_scope_for_line(lineno)
+        parent = holding_scope.parent
+        return isinstance(pyname, pynames.AssignedName) and \
+            pyname in holding_scope.get_names().values() and \
+            holding_scope.get_kind() == 'Function' and \
+            parent is not None and parent.get_kind() == 'Class'