diff --git a/src/structs.h b/src/structs.h
index a543d3b..9f1d479 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -3628,15 +3628,17 @@
  */
 typedef enum
 {
-    TYPE_UNKNOWN = 0,
-    TYPE_EQUAL,		// ==
-    TYPE_NEQUAL,	// !=
-    TYPE_GREATER,	// >
-    TYPE_GEQUAL,	// >=
-    TYPE_SMALLER,	// <
-    TYPE_SEQUAL,	// <=
-    TYPE_MATCH,		// =~
-    TYPE_NOMATCH,	// !~
+    ETYPE_UNKNOWN = 0,
+    ETYPE_EQUAL,	// ==
+    ETYPE_NEQUAL,	// !=
+    ETYPE_GREATER,	// >
+    ETYPE_GEQUAL,	// >=
+    ETYPE_SMALLER,	// <
+    ETYPE_SEQUAL,	// <=
+    ETYPE_MATCH,	// =~
+    ETYPE_NOMATCH,	// !~
+    ETYPE_IS,		// is
+    ETYPE_ISNOT,	// isnot
 } exptype_T;
 
 /*