diff --git a/diff.js b/diff.js
index 84d5cff..c1b9c02 100644
--- a/diff.js
+++ b/diff.js
@@ -599,6 +599,26 @@ object.Constructor('OR', Object.assign(Object.create(Pattern.prototype), {
 	},
 }))
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
+// XXX XOR
+var XOR =
+module.XOR = 
+object.Constructor('XOR', Object.assign(Object.create(Pattern.prototype), {
+	__cmp__: function(obj, cmp, context){
+		/* XXX
+		for(var m of this.members){
+			if(cmp(m, obj, context)){
+				return true
+			}
+		}
+		return false
+		//*/
+	},
+	__init__: function(...members){
+		this.members = members
+	},
+}))
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
 // Will compare as true if all of the .members compare as true...
 var AND = 
diff --git a/format.js b/format.js
index 1118c7c..6fbeaaf 100644
--- a/format.js
+++ b/format.js
@@ -14,7 +14,7 @@ var diff = require('./diff')
 var {
 	ANY,
 	NULL, BOOL, B, NUMBER, N, STRING, S, ARRAY, L, FUNCTION, F,
-	OR, AND, NOT,
+	OR, XOR, AND, NOT,
 	AT, OF, IN,
 	VAR, LIKE, TEST,
 	// non-pattern values...