Introduced yes/no/unknown value enum.

editor/editor.pro

@@ -25,3 +25,4 @@ HEADERS += \
   server_api.hpp \
   ui2oh.hpp \
   xml_feature.hpp \
+  yes_no_unknown.hpp \

editor/yes_no_unknown.hpp

@@ -0,0 +1,27 @@
+#pragma once
+
+#include "std/cstdint.hpp"
+#include "std/string.hpp"
+
+/// Used to store and edit 3-state OSM information, for example,
+/// "This place has internet", "does not have", or "it's not specified yet".
+/// Explicit values are given for easier reuse in Java code.
+namespace osm
+{
+enum YesNoUnknown
+{
+  Unknown = 0,
+  Yes = 1,
+  No = 2
+};
+
+inline string DebugPrint(YesNoUnknown value)
+{
+  switch (value)
+  {
+  case Unknown: return "Unknown";
+  case Yes: return "Yes";
+  case No: return "No";
+  }
+}
+}  // namespace osm