agenda for fsa

git-svn-id: https://ws10smt.googlecode.com/svn/trunk@612 ec762483-ff6d-05da-a07a-a48fb63a330f

1 files changed, 26 insertions, 0 deletions

diff --git a/utils/null_traits.h b/utils/null_traits.h
new file mode 100755
index 00000000..fac857d9
--- /dev/null
+++ b/utils/null_traits.h
@@ -0,0 +1,26 @@
+#ifndef NULL_TRAITS_H
+#define NULL_TRAITS_H
+
+template <class V>
+struct null_traits {
+  static V null; //TODO: maybe take out default null and make ppl explicitly define?  they may be surprised that they need to when they include a header lib that uses null_traits
+};
+// global bool is_null(V const& v)
+
+// definitely override this, and possibly set_null and is_null.  that's the point.
+template <class V>
+V null_traits<V>::null;
+//TODO: are we getting single init of the static null object?
+
+template <class V>
+void set_null(V &v) {
+  v=null_traits<V>::null;
+}
+
+template <class V>
+void is_null(V const& v) {
+  return v==null_traits<V>::null;
+}
+
+
+#endif