New node pattern to express alternatives.

git-svn-id: https://wala.svn.sourceforge.net/svnroot/wala/trunk@4435 f5eafffb-2e1d-0410-98e4-8ec43c5233c4

com.ibm.wala.cast/source/java/com/ibm/wala/cast/tree/pattern/Alt.java

@@ -0,0 +1,23 @@
+package com.ibm.wala.cast.tree.pattern;
+
+import com.ibm.wala.cast.tree.CAstNode;
+
+/**
+ * Pattern to match one of two alternatives.
+ * 
+ * @author mschaefer
+ *
+ */
+public class Alt implements NodePattern {
+  private final NodePattern left, right;
+  
+  public Alt(NodePattern left, NodePattern right) {
+    this.left = left;
+    this.right = right;
+  }
+
+  public boolean matches(CAstNode node) {
+    return left.matches(node) || right.matches(node);
+  }
+
+}