--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Implab/Automaton/RegularExpressions/BinaryToken.cs	Wed Feb 24 08:39:53 2016 +0300
@@ -0,0 +1,21 @@
+using Implab;
+
+namespace Implab.Automaton.RegularExpressions {
+    public abstract class BinaryToken<TTag> : Token<TTag> {
+        readonly Token<TTag> m_left;
+        readonly Token<TTag> m_right;
+
+        public Token<TTag> Left {
+            get { return m_left; }
+        }
+
+        public Token<TTag> Right {
+            get { return m_right; }
+        }
+
+        protected BinaryToken(Token<TTag> left, Token<TTag> right) {
+            Safe.ArgumentNotNull(m_left = left, "left");
+            Safe.ArgumentNotNull(m_right = right, "right");
+        }
+    }
+}