diff --git a/src/range_factory.cc b/src/range_factory.cc
new file mode 100644
index 0000000..4c58044
--- /dev/null
+++ b/src/range_factory.cc
@@ -0,0 +1 @@
+// -*- C++ -*-
diff --git a/src/range_factory.h b/src/range_factory.h
new file mode 100644
index 0000000..4c58044
--- /dev/null
+++ b/src/range_factory.h
@@ -0,0 +1 @@
+// -*- C++ -*-