1 files changed, 72 insertions, 0 deletions
diff --git a/src/runtime/ovalue.r b/src/runtime/ovalue.r
new file mode 100644
index 0000000..e428868
--- /dev/null
+++ b/src/runtime/ovalue.r
@@ -0,0 +1,72 @@
+/*
+ * File: ovalue.r
+ *  Contents: nonnull, null, value, conj
+ */
+
+"\\x - test x for nonnull value."
+
+operator{0,1} \ nonnull(underef x -> dx)
+   abstract {
+      return type(x)
+      }
+   /*
+    * If the dereferenced value dx is not null, the pre-dereferenced
+    *  x is returned, otherwise, the function fails.
+    */
+   if is:null(dx) then
+      inline {
+         fail;
+         }
+   else {
+      inline {
+         return x;
+         }
+      }
+end
+
+
+
+"/x - test x for null value."
+
+operator{0,1} / null(underef x -> dx)
+   abstract {
+      return type(x)
+      }
+   /*
+    * If the dereferenced value dx is null, the pre-derefereneced value
+    *  x is returned, otherwise, the function fails.
+    */
+   if is:null(dx) then {
+      inline {
+         return x;
+         }
+      }
+   else
+      inline {
+         fail;
+      }
+end
+
+
+".x - produce value of x."
+
+operator{1} . value(x)
+  abstract {
+     return type(x)
+     }
+  inline {
+     return x;
+     }
+end
+
+
+"x & y - produce value of y."
+
+operator{1} & conj(underef x, underef y)
+   abstract {
+      return type(y)
+      }
+   inline {
+      return y;
+      }
+end