diff -r 4ebc2e2fb97c -r 71c04702a3d5 src/jdk.jshell/share/classes/jdk/jshell/GeneralWrap.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.jshell/share/classes/jdk/jshell/GeneralWrap.java	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jshell;
+
+/**
+ * Common interface for all wrappings of snippet source to Java source.
+ *
+ * @author Robert Field
+ */
+interface GeneralWrap {
+
+    String wrapped();
+
+    int snippetIndexToWrapIndex(int sni);
+
+    int wrapIndexToSnippetIndex(int wi);
+
+    default int wrapIndexToSnippetIndex(long wi) {
+        return wrapIndexToSnippetIndex((int) wi);
+    }
+
+    int firstSnippetIndex();
+
+    int lastSnippetIndex();
+
+    int snippetLineToWrapLine(int snline);
+
+    int wrapLineToSnippetLine(int wline);
+
+    int firstSnippetLine();
+
+    int lastSnippetLine();
+
+    default String debugPos(long lpos) {
+        int pos = (int) lpos;
+        int len = wrapped().length();
+        return wrapped().substring(Math.max(0, pos - 10), Math.max(0, Math.min(len, pos)))
+                + "###"
+                + wrapped().substring(Math.max(0, Math.min(len, pos)), Math.max(0, Math.min(len, pos + 10)));
+    }
+}