Merge pull request #352 from cweider/modulize-share

Module Sharing

18 files changed, 800 insertions, 4295 deletions

diff --git a/static/js/AttributePoolFactory.js b/static/js/AttributePoolFactory.js
new file mode 100644
index 00000000..00b58dbb
--- /dev/null
+++ b/static/js/AttributePoolFactory.js
@@ -0,0 +1,90 @@
+/**
+ * This code represents the Attribute Pool Object of the original Etherpad.
+ * 90% of the code is still like in the original Etherpad
+ * Look at https://github.com/ether/pad/blob/master/infrastructure/ace/www/easysync2.js
+ * You can find a explanation what a attribute pool is here:
+ * https://github.com/Pita/etherpad-lite/blob/master/doc/easysync/easysync-notes.txt
+ */
+
+/*
+ * Copyright 2009 Google Inc., 2011 Peter 'Pita' Martischka (Primary Technology Ltd)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+exports.createAttributePool = function () {
+  var p = {};
+  p.numToAttrib = {}; // e.g. {0: ['foo','bar']}
+  p.attribToNum = {}; // e.g. {'foo,bar': 0}
+  p.nextNum = 0;
+
+  p.putAttrib = function (attrib, dontAddIfAbsent) {
+    var str = String(attrib);
+    if (str in p.attribToNum) {
+      return p.attribToNum[str];
+    }
+    if (dontAddIfAbsent) {
+      return -1;
+    }
+    var num = p.nextNum++;
+    p.attribToNum[str] = num;
+    p.numToAttrib[num] = [String(attrib[0] || ''), String(attrib[1] || '')];
+    return num;
+  };
+
+  p.getAttrib = function (num) {
+    var pair = p.numToAttrib[num];
+    if (!pair) {
+      return pair;
+    }
+    return [pair[0], pair[1]]; // return a mutable copy
+  };
+
+  p.getAttribKey = function (num) {
+    var pair = p.numToAttrib[num];
+    if (!pair) return '';
+    return pair[0];
+  };
+
+  p.getAttribValue = function (num) {
+    var pair = p.numToAttrib[num];
+    if (!pair) return '';
+    return pair[1];
+  };
+
+  p.eachAttrib = function (func) {
+    for (var n in p.numToAttrib) {
+      var pair = p.numToAttrib[n];
+      func(pair[0], pair[1]);
+    }
+  };
+
+  p.toJsonable = function () {
+    return {
+      numToAttrib: p.numToAttrib,
+      nextNum: p.nextNum
+    };
+  };
+
+  p.fromJsonable = function (obj) {
+    p.numToAttrib = obj.numToAttrib;
+    p.nextNum = obj.nextNum;
+    p.attribToNum = {};
+    for (var n in p.numToAttrib) {
+      p.attribToNum[String(p.numToAttrib[n])] = Number(n);
+    }
+    return p;
+  };
+
+  return p;
+}
diff --git a/static/js/easysync2.js b/static/js/Changeset.js
index cef868a1..715836d5 100644
--- a/static/js/easysync2.js
+++ b/static/js/Changeset.js
@@ -1,13 +1,16 @@
+/*
+ * This is the Changeset library copied from the old Etherpad with some modifications to use it in node.js
+ * Can be found in https://github.com/ether/pad/blob/master/infrastructure/ace/www/easysync2.js
+ */
+
 /**
- * This code is mostly from the old Etherpad. Please help us to comment this code. 
+ * This code is mostly from the old Etherpad. Please help us to comment this code.
  * This helps other people to understand this code better and helps them to improve it.
  * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
  */
 
-// THIS FILE IS ALSO AN APPJET MODULE: etherpad.collab.ace.easysync2
-// %APPJET%: jimport("com.etherpad.Easysync2Support");
-/**
- * Copyright 2009 Google Inc.
+/*
+ * Copyright 2009 Google Inc., 2011 Peter 'Pita' Martischka (Primary Technology Ltd)
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -22,203 +25,101 @@
  * limitations under the License.
  */
 
-//var _opt = (this.Easysync2Support || null);
-var _opt = null; // disable optimization for now
-
-function AttribPool()
-{
-  var p = {};
-  p.numToAttrib = {}; // e.g. {0: ['foo','bar']}
-  p.attribToNum = {}; // e.g. {'foo,bar': 0}
-  p.nextNum = 0;
-
-  p.putAttrib = function(attrib, dontAddIfAbsent)
-  {
-    var str = String(attrib);
-    if (str in p.attribToNum)
-    {
-      return p.attribToNum[str];
-    }
-    if (dontAddIfAbsent)
-    {
-      return -1;
-    }
-    var num = p.nextNum++;
-    p.attribToNum[str] = num;
-    p.numToAttrib[num] = [String(attrib[0] || ''), String(attrib[1] || '')];
-    return num;
-  };
-
-  p.getAttrib = function(num)
-  {
-    var pair = p.numToAttrib[num];
-    if (!pair) return pair;
-    return [pair[0], pair[1]]; // return a mutable copy
-  };
+var AttributePoolFactory = require("/AttributePoolFactory");
 
-  p.getAttribKey = function(num)
-  {
-    var pair = p.numToAttrib[num];
-    if (!pair) return '';
-    return pair[0];
-  };
-
-  p.getAttribValue = function(num)
-  {
-    var pair = p.numToAttrib[num];
-    if (!pair) return '';
-    return pair[1];
-  };
-
-  p.eachAttrib = function(func)
-  {
-    for (var n in p.numToAttrib)
-    {
-      var pair = p.numToAttrib[n];
-      func(pair[0], pair[1]);
-    }
-  };
-
-  p.toJsonable = function()
-  {
-    return {
-      numToAttrib: p.numToAttrib,
-      nextNum: p.nextNum
-    };
-  };
-
-  p.fromJsonable = function(obj)
-  {
-    p.numToAttrib = obj.numToAttrib;
-    p.nextNum = obj.nextNum;
-    p.attribToNum = {};
-    for (var n in p.numToAttrib)
-    {
-      p.attribToNum[String(p.numToAttrib[n])] = Number(n);
-    }
-    return p;
-  };
-
-  return p;
-}
+var _opt = null;
 
-var Changeset = {};
-
-Changeset.error = function error(msg)
-{
+//var exports = {};
+exports.error = function error(msg) {
   var e = new Error(msg);
   e.easysync = true;
   throw e;
 };
-Changeset.assert = function assert(b, msgParts)
-{
-  if (!b)
-  {
+exports.assert = function assert(b, msgParts) {
+  if (!b) {
     var msg = Array.prototype.slice.call(arguments, 1).join('');
-    Changeset.error("Changeset: " + msg);
+    exports.error("exports: " + msg);
   }
 };
 
-Changeset.parseNum = function(str)
-{
+exports.parseNum = function (str) {
   return parseInt(str, 36);
 };
-Changeset.numToString = function(num)
-{
+exports.numToString = function (num) {
   return num.toString(36).toLowerCase();
 };
-Changeset.toBaseTen = function(cs)
-{
+exports.toBaseTen = function (cs) {
   var dollarIndex = cs.indexOf('$');
   var beforeDollar = cs.substring(0, dollarIndex);
   var fromDollar = cs.substring(dollarIndex);
-  return beforeDollar.replace(/[0-9a-z]+/g, function(s)
-  {
-    return String(Changeset.parseNum(s));
+  return beforeDollar.replace(/[0-9a-z]+/g, function (s) {
+    return String(exports.parseNum(s));
   }) + fromDollar;
 };
 
-Changeset.oldLen = function(cs)
-{
-  return Changeset.unpack(cs).oldLen;
+exports.oldLen = function (cs) {
+  return exports.unpack(cs).oldLen;
 };
-Changeset.newLen = function(cs)
-{
-  return Changeset.unpack(cs).newLen;
+exports.newLen = function (cs) {
+  return exports.unpack(cs).newLen;
 };
 
-Changeset.opIterator = function(opsStr, optStartIndex)
-{
+exports.opIterator = function (opsStr, optStartIndex) {
   //print(opsStr);
   var regex = /((?:\*[0-9a-z]+)*)(?:\|([0-9a-z]+))?([-+=])([0-9a-z]+)|\?|/g;
   var startIndex = (optStartIndex || 0);
   var curIndex = startIndex;
   var prevIndex = curIndex;
 
-  function nextRegexMatch()
-  {
+  function nextRegexMatch() {
     prevIndex = curIndex;
     var result;
-    if (_opt)
-    {
+    if (_opt) {
       result = _opt.nextOpInString(opsStr, curIndex);
-      if (result)
-      {
-        if (result.opcode() == '?')
-        {
-          Changeset.error("Hit error opcode in op stream");
+      if (result) {
+        if (result.opcode() == '?') {
+          exports.error("Hit error opcode in op stream");
         }
         curIndex = result.lastIndex();
       }
-    }
-    else
-    {
+    } else {
       regex.lastIndex = curIndex;
       result = regex.exec(opsStr);
       curIndex = regex.lastIndex;
-      if (result[0] == '?')
-      {
-        Changeset.error("Hit error opcode in op stream");
+      if (result[0] == '?') {
+        exports.error("Hit error opcode in op stream");
       }
     }
     return result;
   }
   var regexResult = nextRegexMatch();
-  var obj = Changeset.newOp();
+  var obj = exports.newOp();
 
-  function next(optObj)
-  {
+  function next(optObj) {
     var op = (optObj || obj);
-    if (_opt && regexResult)
-    {
+    if (_opt && regexResult) {
       op.attribs = regexResult.attribs();
       op.lines = regexResult.lines();
       op.chars = regexResult.chars();
       op.opcode = regexResult.opcode();
       regexResult = nextRegexMatch();
-    }
-    else if ((!_opt) && regexResult[0])
-    {
+    } else if ((!_opt) && regexResult[0]) {
       op.attribs = regexResult[1];
-      op.lines = Changeset.parseNum(regexResult[2] || 0);
+      op.lines = exports.parseNum(regexResult[2] || 0);
       op.opcode = regexResult[3];
-      op.chars = Changeset.parseNum(regexResult[4]);
+      op.chars = exports.parseNum(regexResult[4]);
       regexResult = nextRegexMatch();
-    }
-    else
-    {
-      Changeset.clearOp(op);
+    } else {
+      exports.clearOp(op);
     }
     return op;
   }
 
-  function hasNext()
-  {
+  function hasNext() {
     return !!(_opt ? regexResult : regexResult[0]);
   }
 
-  function lastIndex()
-  {
+  function lastIndex() {
     return prevIndex;
   }
   return {
@@ -228,15 +129,13 @@ Changeset.opIterator = function(opsStr, optStartIndex)
   };
 };
 
-Changeset.clearOp = function(op)
-{
+exports.clearOp = function (op) {
   op.opcode = '';
   op.chars = 0;
   op.lines = 0;
   op.attribs = '';
 };
-Changeset.newOp = function(optOpcode)
-{
+exports.newOp = function (optOpcode) {
   return {
     opcode: (optOpcode || ''),
     chars: 0,
@@ -244,8 +143,7 @@ Changeset.newOp = function(optOpcode)
     attribs: ''
   };
 };
-Changeset.cloneOp = function(op)
-{
+exports.cloneOp = function (op) {
   return {
     opcode: op.opcode,
     chars: op.chars,
@@ -253,60 +151,54 @@ Changeset.cloneOp = function(op)
     attribs: op.attribs
   };
 };
-Changeset.copyOp = function(op1, op2)
-{
+exports.copyOp = function (op1, op2) {
   op2.opcode = op1.opcode;
   op2.chars = op1.chars;
   op2.lines = op1.lines;
   op2.attribs = op1.attribs;
 };
-Changeset.opString = function(op)
-{
+exports.opString = function (op) {
   // just for debugging
   if (!op.opcode) return 'null';
-  var assem = Changeset.opAssembler();
+  var assem = exports.opAssembler();
   assem.append(op);
   return assem.toString();
 };
-Changeset.stringOp = function(str)
-{
+exports.stringOp = function (str) {
   // just for debugging
-  return Changeset.opIterator(str).next();
+  return exports.opIterator(str).next();
 };
 
-Changeset.checkRep = function(cs)
-{
+exports.checkRep = function (cs) {
   // doesn't check things that require access to attrib pool (e.g. attribute order)
   // or original string (e.g. newline positions)
-  var unpacked = Changeset.unpack(cs);
+  var unpacked = exports.unpack(cs);
   var oldLen = unpacked.oldLen;
   var newLen = unpacked.newLen;
   var ops = unpacked.ops;
   var charBank = unpacked.charBank;
 
-  var assem = Changeset.smartOpAssembler();
+  var assem = exports.smartOpAssembler();
   var oldPos = 0;
   var calcNewLen = 0;
   var numInserted = 0;
-  var iter = Changeset.opIterator(ops);
-  while (iter.hasNext())
-  {
+  var iter = exports.opIterator(ops);
+  while (iter.hasNext()) {
     var o = iter.next();
-    switch (o.opcode)
-    {
+    switch (o.opcode) {
     case '=':
       oldPos += o.chars;
       calcNewLen += o.chars;
       break;
     case '-':
       oldPos += o.chars;
-      Changeset.assert(oldPos < oldLen, oldPos, " >= ", oldLen, " in ", cs);
+      exports.assert(oldPos < oldLen, oldPos, " >= ", oldLen, " in ", cs);
       break;
     case '+':
       {
         calcNewLen += o.chars;
         numInserted += o.chars;
-        Changeset.assert(calcNewLen < newLen, calcNewLen, " >= ", newLen, " in ", cs);
+        exports.assert(calcNewLen < newLen, calcNewLen, " >= ", newLen, " in ", cs);
         break;
       }
     }
@@ -315,75 +207,62 @@ Changeset.checkRep = function(cs)
 
   calcNewLen += oldLen - oldPos;
   charBank = charBank.substring(0, numInserted);
-  while (charBank.length < numInserted)
-  {
+  while (charBank.length < numInserted) {
     charBank += "?";
   }
 
   assem.endDocument();
-  var normalized = Changeset.pack(oldLen, calcNewLen, assem.toString(), charBank);
-  Changeset.assert(normalized == cs, normalized, ' != ', cs);
+  var normalized = exports.pack(oldLen, calcNewLen, assem.toString(), charBank);
+  exports.assert(normalized == cs, normalized, ' != ', cs);
 
   return cs;
 }
 
-Changeset.smartOpAssembler = function()
-{
-  // Like opAssembler but able to produce conforming changesets
+exports.smartOpAssembler = function () {
+  // Like opAssembler but able to produce conforming exportss
   // from slightly looser input, at the cost of speed.
   // Specifically:
   // - merges consecutive operations that can be merged
   // - strips final "="
   // - ignores 0-length changes
   // - reorders consecutive + and - (which margingOpAssembler doesn't do)
-  var minusAssem = Changeset.mergingOpAssembler();
-  var plusAssem = Changeset.mergingOpAssembler();
-  var keepAssem = Changeset.mergingOpAssembler();
-  var assem = Changeset.stringAssembler();
+  var minusAssem = exports.mergingOpAssembler();
+  var plusAssem = exports.mergingOpAssembler();
+  var keepAssem = exports.mergingOpAssembler();
+  var assem = exports.stringAssembler();
   var lastOpcode = '';
   var lengthChange = 0;
 
-  function flushKeeps()
-  {
+  function flushKeeps() {
     assem.append(keepAssem.toString());
     keepAssem.clear();
   }
 
-  function flushPlusMinus()
-  {
+  function flushPlusMinus() {
     assem.append(minusAssem.toString());
     minusAssem.clear();
     assem.append(plusAssem.toString());
     plusAssem.clear();
   }
 
-  function append(op)
-  {
+  function append(op) {
     if (!op.opcode) return;
     if (!op.chars) return;
 
-    if (op.opcode == '-')
-    {
-      if (lastOpcode == '=')
-      {
+    if (op.opcode == '-') {
+      if (lastOpcode == '=') {
         flushKeeps();
       }
       minusAssem.append(op);
       lengthChange -= op.chars;
-    }
-    else if (op.opcode == '+')
-    {
-      if (lastOpcode == '=')
-      {
+    } else if (op.opcode == '+') {
+      if (lastOpcode == '=') {
         flushKeeps();
       }
       plusAssem.append(op);
       lengthChange += op.chars;
-    }
-    else if (op.opcode == '=')
-    {
-      if (lastOpcode != '=')
-      {
+    } else if (op.opcode == '=') {
+      if (lastOpcode != '=') {
         flushPlusMinus();
       }
       keepAssem.append(op);
@@ -391,19 +270,15 @@ Changeset.smartOpAssembler = function()
     lastOpcode = op.opcode;
   }
 
-  function appendOpWithText(opcode, text, attribs, pool)
-  {
-    var op = Changeset.newOp(opcode);
-    op.attribs = Changeset.makeAttribsString(opcode, attribs, pool);
+  function appendOpWithText(opcode, text, attribs, pool) {
+    var op = exports.newOp(opcode);
+    op.attribs = exports.makeAttribsString(opcode, attribs, pool);
     var lastNewlinePos = text.lastIndexOf('\n');
-    if (lastNewlinePos < 0)
-    {
+    if (lastNewlinePos < 0) {
       op.chars = text.length;
       op.lines = 0;
       append(op);
-    }
-    else
-    {
+    } else {
       op.chars = lastNewlinePos + 1;
       op.lines = text.match(/\n/g).length;
       append(op);
@@ -413,15 +288,13 @@ Changeset.smartOpAssembler = function()
     }
   }
 
-  function toString()
-  {
+  function toString() {
     flushPlusMinus();
     flushKeeps();
     return assem.toString();
   }
 
-  function clear()
-  {
+  function clear() {
     minusAssem.clear();
     plusAssem.clear();
     keepAssem.clear();
@@ -429,13 +302,11 @@ Changeset.smartOpAssembler = function()
     lengthChange = 0;
   }
 
-  function endDocument()
-  {
+  function endDocument() {
     keepAssem.endDocument();
   }
 
-  function getLengthChange()
-  {
+  function getLengthChange() {
     return lengthChange;
   }
 
@@ -449,29 +320,23 @@ Changeset.smartOpAssembler = function()
   };
 };
 
-if (_opt)
-{
-  Changeset.mergingOpAssembler = function()
-  {
+if (_opt) {
+  exports.mergingOpAssembler = function () {
     var assem = _opt.mergingOpAssembler();
 
-    function append(op)
-    {
+    function append(op) {
       assem.append(op.opcode, op.chars, op.lines, op.attribs);
     }
 
-    function toString()
-    {
+    function toString() {
       return assem.toString();
     }
 
-    function clear()
-    {
+    function clear() {
       assem.clear();
     }
 
-    function endDocument()
-    {
+    function endDocument() {
       assem.endDocument();
     }
 
@@ -482,17 +347,14 @@ if (_opt)
       endDocument: endDocument
     };
   };
-}
-else
-{
-  Changeset.mergingOpAssembler = function()
-  {
+} else {
+  exports.mergingOpAssembler = function () {
     // This assembler can be used in production; it efficiently
     // merges consecutive operations that are mergeable, ignores
     // no-ops, and drops final pure "keeps".  It does not re-order
     // operations.
-    var assem = Changeset.opAssembler();
-    var bufOp = Changeset.newOp();
+    var assem = exports.opAssembler();
+    var bufOp = exports.newOp();
 
     // If we get, for example, insertions [xxx\n,yyy], those don't merge,
     // but if we get [xxx\n,yyy,zzz\n], that merges to [xxx\nyyyzzz\n].
@@ -500,19 +362,13 @@ else
     // ops immediately after it.
     var bufOpAdditionalCharsAfterNewline = 0;
 
-    function flush(isEndDocument)
-    {
-      if (bufOp.opcode)
-      {
-        if (isEndDocument && bufOp.opcode == '=' && !bufOp.attribs)
-        {
+    function flush(isEndDocument) {
+      if (bufOp.opcode) {
+        if (isEndDocument && bufOp.opcode == '=' && !bufOp.attribs) {
           // final merged keep, leave it implicit
-        }
-        else
-        {
+        } else {
           assem.append(bufOp);
-          if (bufOpAdditionalCharsAfterNewline)
-          {
+          if (bufOpAdditionalCharsAfterNewline) {
             bufOp.chars = bufOpAdditionalCharsAfterNewline;
             bufOp.lines = 0;
             assem.append(bufOp);
@@ -523,53 +379,40 @@ else
       }
     }
 
-    function append(op)
-    {
-      if (op.chars > 0)
-      {
-        if (bufOp.opcode == op.opcode && bufOp.attribs == op.attribs)
-        {
-          if (op.lines > 0)
-          {
+    function append(op) {
+      if (op.chars > 0) {
+        if (bufOp.opcode == op.opcode && bufOp.attribs == op.attribs) {
+          if (op.lines > 0) {
             // bufOp and additional chars are all mergeable into a multi-line op
             bufOp.chars += bufOpAdditionalCharsAfterNewline + op.chars;
             bufOp.lines += op.lines;
             bufOpAdditionalCharsAfterNewline = 0;
-          }
-          else if (bufOp.lines == 0)
-          {
+          } else if (bufOp.lines == 0) {
             // both bufOp and op are in-line
             bufOp.chars += op.chars;
-          }
-          else
-          {
+          } else {
             // append in-line text to multi-line bufOp
             bufOpAdditionalCharsAfterNewline += op.chars;
           }
-        }
-        else
-        {
+        } else {
           flush();
-          Changeset.copyOp(op, bufOp);
+          exports.copyOp(op, bufOp);
         }
       }
     }
 
-    function endDocument()
-    {
+    function endDocument() {
       flush(true);
     }
 
-    function toString()
-    {
+    function toString() {
       flush();
       return assem.toString();
     }
 
-    function clear()
-    {
+    function clear() {
       assem.clear();
-      Changeset.clearOp(bufOp);
+      exports.clearOp(bufOp);
     }
     return {
       append: append,
@@ -580,26 +423,20 @@ else
   };
 }
 
-if (_opt)
-{
-  Changeset.opAssembler = function()
-  {
+if (_opt) {
+  exports.opAssembler = function () {
     var assem = _opt.opAssembler();
     // this function allows op to be mutated later (doesn't keep a ref)
 
-
-    function append(op)
-    {
+    function append(op) {
       assem.append(op.opcode, op.chars, op.lines, op.attribs);
     }
 
-    function toString()
-    {
+    function toString() {
       return assem.toString();
     }
 
-    function clear()
-    {
+    function clear() {
       assem.clear();
     }
     return {
@@ -608,33 +445,25 @@ if (_opt)
       clear: clear
     };
   };
-}
-else
-{
-  Changeset.opAssembler = function()
-  {
+} else {
+  exports.opAssembler = function () {
     var pieces = [];
     // this function allows op to be mutated later (doesn't keep a ref)
 
-
-    function append(op)
-    {
+    function append(op) {
       pieces.push(op.attribs);
-      if (op.lines)
-      {
-        pieces.push('|', Changeset.numToString(op.lines));
+      if (op.lines) {
+        pieces.push('|', exports.numToString(op.lines));
       }
       pieces.push(op.opcode);
-      pieces.push(Changeset.numToString(op.chars));
+      pieces.push(exports.numToString(op.chars));
     }
 
-    function toString()
-    {
+    function toString() {
       return pieces.join('');
     }
 
-    function clear()
-    {
+    function clear() {
       pieces.length = 0;
     }
     return {
@@ -645,38 +474,32 @@ else
   };
 }
 
-Changeset.stringIterator = function(str)
-{
+exports.stringIterator = function (str) {
   var curIndex = 0;
 
-  function assertRemaining(n)
-  {
-    Changeset.assert(n <= remaining(), "!(", n, " <= ", remaining(), ")");
+  function assertRemaining(n) {
+    exports.assert(n <= remaining(), "!(", n, " <= ", remaining(), ")");
   }
 
-  function take(n)
-  {
+  function take(n) {
     assertRemaining(n);
     var s = str.substr(curIndex, n);
     curIndex += n;
     return s;
   }
 
-  function peek(n)
-  {
+  function peek(n) {
     assertRemaining(n);
     var s = str.substr(curIndex, n);
     return s;
   }
 
-  function skip(n)
-  {
+  function skip(n) {
     assertRemaining(n);
     curIndex += n;
   }
 
-  function remaining()
-  {
+  function remaining() {
     return str.length - curIndex;
   }
   return {
@@ -687,17 +510,14 @@ Changeset.stringIterator = function(str)
   };
 };
 
-Changeset.stringAssembler = function()
-{
+exports.stringAssembler = function () {
   var pieces = [];
 
-  function append(x)
-  {
+  function append(x) {
     pieces.push(String(x));
   }
 
-  function toString()
-  {
+  function toString() {
     return pieces.join('');
   }
   return {
@@ -707,10 +527,9 @@ Changeset.stringAssembler = function()
 };
 
 // "lines" need not be an array as long as it supports certain calls (lines_foo inside).
-Changeset.textLinesMutator = function(lines)
-{
+exports.textLinesMutator = function (lines) {
   // Mutates lines, an array of strings, in place.
-  // Mutation operations have the same constraints as changeset operations
+  // Mutation operations have the same constraints as exports operations
   // with respect to newlines, but not the other additional constraints
   // (i.e. ins/del ordering, forbidden no-ops, non-mergeability, final newline).
   // Can be used to mutate lists of strings where the last char of each string
@@ -727,120 +546,87 @@ Changeset.textLinesMutator = function(lines)
   // invariant: if (inSplice && (curLine >= curSplice[0] + curSplice.length - 2)) then
   //            curCol == 0
 
-  function lines_applySplice(s)
-  {
+  function lines_applySplice(s) {
     lines.splice.apply(lines, s);
   }
 
-  function lines_toSource()
-  {
+  function lines_toSource() {
     return lines.toSource();
   }
 
-  function lines_get(idx)
-  {
-    if (lines.get)
-    {
+  function lines_get(idx) {
+    if (lines.get) {
       return lines.get(idx);
-    }
-    else
-    {
+    } else {
       return lines[idx];
     }
   }
   // can be unimplemented if removeLines's return value not needed
 
-
-  function lines_slice(start, end)
-  {
-    if (lines.slice)
-    {
+  function lines_slice(start, end) {
+    if (lines.slice) {
       return lines.slice(start, end);
-    }
-    else
-    {
+    } else {
       return [];
     }
   }
 
-  function lines_length()
-  {
-    if ((typeof lines.length) == "number")
-    {
+  function lines_length() {
+    if ((typeof lines.length) == "number") {
       return lines.length;
-    }
-    else
-    {
+    } else {
       return lines.length();
     }
   }
 
-  function enterSplice()
-  {
+  function enterSplice() {
     curSplice[0] = curLine;
     curSplice[1] = 0;
-    if (curCol > 0)
-    {
+    if (curCol > 0) {
       putCurLineInSplice();
     }
     inSplice = true;
   }
 
-  function leaveSplice()
-  {
+  function leaveSplice() {
     lines_applySplice(curSplice);
     curSplice.length = 2;
     curSplice[0] = curSplice[1] = 0;
     inSplice = false;
   }
 
-  function isCurLineInSplice()
-  {
+  function isCurLineInSplice() {
     return (curLine - curSplice[0] < (curSplice.length - 2));
   }
 
-  function debugPrint(typ)
-  {
+  function debugPrint(typ) {
     print(typ + ": " + curSplice.toSource() + " / " + curLine + "," + curCol + " / " + lines_toSource());
   }
 
-  function putCurLineInSplice()
-  {
-    if (!isCurLineInSplice())
-    {
+  function putCurLineInSplice() {
+    if (!isCurLineInSplice()) {
       curSplice.push(lines_get(curSplice[0] + curSplice[1]));
       curSplice[1]++;
     }
     return 2 + curLine - curSplice[0];
   }
 
-  function skipLines(L, includeInSplice)
-  {
-    if (L)
-    {
-      if (includeInSplice)
-      {
-        if (!inSplice)
-        {
+  function skipLines(L, includeInSplice) {
+    if (L) {
+      if (includeInSplice) {
+        if (!inSplice) {
           enterSplice();
         }
-        for (var i = 0; i < L; i++)
-        {
+        for (var i = 0; i < L; i++) {
           curCol = 0;
           putCurLineInSplice();
           curLine++;
         }
-      }
-      else
-      {
-        if (inSplice)
-        {
-          if (L > 1)
-          {
+      } else {
+        if (inSplice) {
+          if (L > 1) {
             leaveSplice();
-          }
-          else
-          {
+          } else {
             putCurLineInSplice();
           }
         }
@@ -857,22 +643,15 @@ Changeset.textLinesMutator = function(lines)
     //debugPrint("skip");
   }
 
-  function skip(N, L, includeInSplice)
-  {
-    if (N)
-    {
-      if (L)
-      {
+  function skip(N, L, includeInSplice) {
+    if (N) {
+      if (L) {
         skipLines(L, includeInSplice);
-      }
-      else
-      {
-        if (includeInSplice && !inSplice)
-        {
+      } else {
+        if (includeInSplice && !inSplice) {
           enterSplice();
         }
-        if (inSplice)
-        {
+        if (inSplice) {
           putCurLineInSplice();
         }
         curCol += N;
@@ -881,34 +660,26 @@ Changeset.textLinesMutator = function(lines)
     }
   }
 
-  function removeLines(L)
-  {
+  function removeLines(L) {
     var removed = '';
-    if (L)
-    {
-      if (!inSplice)
-      {
+    if (L) {
+      if (!inSplice) {
         enterSplice();
       }
 
-      function nextKLinesText(k)
-      {
+      function nextKLinesText(k) {
         var m = curSplice[0] + curSplice[1];
         return lines_slice(m, m + k).join('');
       }
-      if (isCurLineInSplice())
-      {
+      if (isCurLineInSplice()) {
         //print(curCol);
-        if (curCol == 0)
-        {
+        if (curCol == 0) {
           removed = curSplice[curSplice.length - 1];
           // print("FOO"); // case foo
           curSplice.length--;
           removed += nextKLinesText(L - 1);
           curSplice[1] += L - 1;
-        }
-        else
-        {
+        } else {
           removed = nextKLinesText(L - 1);
           curSplice[1] += L - 1;
           var sline = curSplice.length - 1;
@@ -916,9 +687,7 @@ Changeset.textLinesMutator = function(lines)
           curSplice[sline] = curSplice[sline].substring(0, curCol) + lines_get(curSplice[0] + curSplice[1]);
           curSplice[1] += 1;
         }
-      }
-      else
-      {
+      } else {
         removed = nextKLinesText(L);
         curSplice[1] += L;
       }
@@ -927,19 +696,13 @@ Changeset.textLinesMutator = function(lines)
     return removed;
   }
 
-  function remove(N, L)
-  {
+  function remove(N, L) {
     var removed = '';
-    if (N)
-    {
-      if (L)
-      {
+    if (N) {
+      if (L) {
         return removeLines(L);
-      }
-      else
-      {
-        if (!inSplice)
-        {
+      } else {
+        if (!inSplice) {
           enterSplice();
         }
         var sline = putCurLineInSplice();
@@ -951,19 +714,14 @@ Changeset.textLinesMutator = function(lines)
     return removed;
   }
 
-  function insert(text, L)
-  {
-    if (text)
-    {
-      if (!inSplice)
-      {
+  function insert(text, L) {
+    if (text) {
+      if (!inSplice) {
         enterSplice();
       }
-      if (L)
-      {
-        var newLines = Changeset.splitTextLines(text);
-        if (isCurLineInSplice())
-        {
+      if (L) {
+        var newLines = exports.splitTextLines(text);
+        if (isCurLineInSplice()) {
           //if (curCol == 0) {
           //curSplice.length--;
           //curSplice[1]--;
@@ -982,15 +740,11 @@ Changeset.textLinesMutator = function(lines)
           curSplice.push(theLine.substring(lineCol));
           curCol = 0;
           //}
-        }
-        else
-        {
+        } else {
           Array.prototype.push.apply(curSplice, newLines);
           curLine += newLines.length;
         }
-      }
-      else
-      {
+      } else {
         var sline = putCurLineInSplice();
         curSplice[sline] = curSplice[sline].substring(0, curCol) + text + curSplice[sline].substring(curCol);
         curCol += text.length;
@@ -999,21 +753,17 @@ Changeset.textLinesMutator = function(lines)
     }
   }
 
-  function hasMore()
-  {
+  function hasMore() {
     //print(lines.length+" / "+inSplice+" / "+(curSplice.length - 2)+" / "+curSplice[1]);
     var docLines = lines_length();
-    if (inSplice)
-    {
+    if (inSplice) {
       docLines += curSplice.length - 2 - curSplice[1];
     }
     return curLine < docLines;
   }
 
-  function close()
-  {
-    if (inSplice)
-    {
+  function close() {
+    if (inSplice) {
       leaveSplice();
     }
     //debugPrint("close");
@@ -1031,21 +781,18 @@ Changeset.textLinesMutator = function(lines)
   return self;
 };
 
-Changeset.applyZip = function(in1, idx1, in2, idx2, func)
-{
-  var iter1 = Changeset.opIterator(in1, idx1);
-  var iter2 = Changeset.opIterator(in2, idx2);
-  var assem = Changeset.smartOpAssembler();
-  var op1 = Changeset.newOp();
-  var op2 = Changeset.newOp();
-  var opOut = Changeset.newOp();
-  while (op1.opcode || iter1.hasNext() || op2.opcode || iter2.hasNext())
-  {
+exports.applyZip = function (in1, idx1, in2, idx2, func) {
+  var iter1 = exports.opIterator(in1, idx1);
+  var iter2 = exports.opIterator(in2, idx2);
+  var assem = exports.smartOpAssembler();
+  var op1 = exports.newOp();
+  var op2 = exports.newOp();
+  var opOut = exports.newOp();
+  while (op1.opcode || iter1.hasNext() || op2.opcode || iter2.hasNext()) {
     if ((!op1.opcode) && iter1.hasNext()) iter1.next(op1);
     if ((!op2.opcode) && iter2.hasNext()) iter2.next(op2);
     func(op1, op2, opOut);
-    if (opOut.opcode)
-    {
+    if (opOut.opcode) {
       //print(opOut.toSource());
       assem.append(opOut);
       opOut.opcode = '';
@@ -1055,17 +802,15 @@ Changeset.applyZip = function(in1, idx1, in2, idx2, func)
   return assem.toString();
 };
 
-Changeset.unpack = function(cs)
-{
+exports.unpack = function (cs) {
   var headerRegex = /Z:([0-9a-z]+)([><])([0-9a-z]+)|/;
   var headerMatch = headerRegex.exec(cs);
-  if ((!headerMatch) || (!headerMatch[0]))
-  {
-    Changeset.error("Not a changeset: " + cs);
+  if ((!headerMatch) || (!headerMatch[0])) {
+    exports.error("Not a exports: " + cs);
   }
-  var oldLen = Changeset.parseNum(headerMatch[1]);
+  var oldLen = exports.parseNum(headerMatch[1]);
   var changeSign = (headerMatch[2] == '>') ? 1 : -1;
-  var changeMag = Changeset.parseNum(headerMatch[3]);
+  var changeMag = exports.parseNum(headerMatch[3]);
   var newLen = oldLen + changeSign * changeMag;
   var opsStart = headerMatch[0].length;
   var opsEnd = cs.indexOf("$");
@@ -1078,28 +823,24 @@ Changeset.unpack = function(cs)
   };
 };
 
-Changeset.pack = function(oldLen, newLen, opsStr, bank)
-{
+exports.pack = function (oldLen, newLen, opsStr, bank) {
   var lenDiff = newLen - oldLen;
-  var lenDiffStr = (lenDiff >= 0 ? '>' + Changeset.numToString(lenDiff) : '<' + Changeset.numToString(-lenDiff));
+  var lenDiffStr = (lenDiff >= 0 ? '>' + exports.numToString(lenDiff) : '<' + exports.numToString(-lenDiff));
   var a = [];
-  a.push('Z:', Changeset.numToString(oldLen), lenDiffStr, opsStr, '$', bank);
+  a.push('Z:', exports.numToString(oldLen), lenDiffStr, opsStr, '$', bank);
   return a.join('');
 };
 
-Changeset.applyToText = function(cs, str)
-{
-  var unpacked = Changeset.unpack(cs);
-  Changeset.assert(str.length == unpacked.oldLen, "mismatched apply: ", str.length, " / ", unpacked.oldLen);
-  var csIter = Changeset.opIterator(unpacked.ops);
-  var bankIter = Changeset.stringIterator(unpacked.charBank);
-  var strIter = Changeset.stringIterator(str);
-  var assem = Changeset.stringAssembler();
-  while (csIter.hasNext())
-  {
+exports.applyToText = function (cs, str) {
+  var unpacked = exports.unpack(cs);
+  exports.assert(str.length == unpacked.oldLen, "mismatched apply: ", str.length, " / ", unpacked.oldLen);
+  var csIter = exports.opIterator(unpacked.ops);
+  var bankIter = exports.stringIterator(unpacked.charBank);
+  var strIter = exports.stringIterator(str);
+  var assem = exports.stringAssembler();
+  while (csIter.hasNext()) {
     var op = csIter.next();
-    switch (op.opcode)
-    {
+    switch (op.opcode) {
     case '+':
       assem.append(bankIter.take(op.chars));
       break;
@@ -1115,17 +856,14 @@ Changeset.applyToText = function(cs, str)
   return assem.toString();
 };
 
-Changeset.mutateTextLines = function(cs, lines)
-{
-  var unpacked = Changeset.unpack(cs);
-  var csIter = Changeset.opIterator(unpacked.ops);
-  var bankIter = Changeset.stringIterator(unpacked.charBank);
-  var mut = Changeset.textLinesMutator(lines);
-  while (csIter.hasNext())
-  {
+exports.mutateTextLines = function (cs, lines) {
+  var unpacked = exports.unpack(cs);
+  var csIter = exports.opIterator(unpacked.ops);
+  var bankIter = exports.stringIterator(unpacked.charBank);
+  var mut = exports.textLinesMutator(lines);
+  while (csIter.hasNext()) {
     var op = csIter.next();
-    switch (op.opcode)
-    {
+    switch (op.opcode) {
     case '+':
       mut.insert(bankIter.take(op.chars), op.lines);
       break;
@@ -1140,8 +878,7 @@ Changeset.mutateTextLines = function(cs, lines)
   mut.close();
 };
 
-Changeset.composeAttributes = function(att1, att2, resultIsMutation, pool)
-{
+exports.composeAttributes = function (att1, att2, resultIsMutation, pool) {
   // att1 and att2 are strings like "*3*f*1c", asMutation is a boolean.
   // Sometimes attribute (key,value) pairs are treated as attribute presence
   // information, while other times they are treated as operations that
@@ -1155,9 +892,8 @@ Changeset.composeAttributes = function(att1, att2, resultIsMutation, pool)
   // ([(bold, true)], [(bold, )], true) -> [(bold, )]
   // ([(bold, true)], [(bold, )], false) -> []
   // pool can be null if att2 has no attributes.
-  if ((!att1) && resultIsMutation)
-  {
-    // In the case of a mutation (i.e. composing two changesets),
+  if ((!att1) && resultIsMutation) {
+    // In the case of a mutation (i.e. composing two exportss),
     // an att2 composed with an empy att1 is just att2.  If att1
     // is part of an attribution string, then att2 may remove
     // attributes that are already gone, so don't do this optimization.
@@ -1165,76 +901,58 @@ Changeset.composeAttributes = function(att1, att2, resultIsMutation, pool)
   }
   if (!att2) return att1;
   var atts = [];
-  att1.replace(/\*([0-9a-z]+)/g, function(_, a)
-  {
-    atts.push(pool.getAttrib(Changeset.parseNum(a)));
+  att1.replace(/\*([0-9a-z]+)/g, function (_, a) {
+    atts.push(pool.getAttrib(exports.parseNum(a)));
     return '';
   });
-  att2.replace(/\*([0-9a-z]+)/g, function(_, a)
-  {
-    var pair = pool.getAttrib(Changeset.parseNum(a));
+  att2.replace(/\*([0-9a-z]+)/g, function (_, a) {
+    var pair = pool.getAttrib(exports.parseNum(a));
     var found = false;
-    for (var i = 0; i < atts.length; i++)
-    {
+    for (var i = 0; i < atts.length; i++) {
       var oldPair = atts[i];
-      if (oldPair[0] == pair[0])
-      {
-        if (pair[1] || resultIsMutation)
-        {
+      if (oldPair[0] == pair[0]) {
+        if (pair[1] || resultIsMutation) {
           oldPair[1] = pair[1];
-        }
-        else
-        {
+        } else {
           atts.splice(i, 1);
         }
         found = true;
         break;
       }
     }
-    if ((!found) && (pair[1] || resultIsMutation))
-    {
+    if ((!found) && (pair[1] || resultIsMutation)) {
       atts.push(pair);
     }
     return '';
   });
   atts.sort();
-  var buf = Changeset.stringAssembler();
-  for (var i = 0; i < atts.length; i++)
-  {
+  var buf = exports.stringAssembler();
+  for (var i = 0; i < atts.length; i++) {
     buf.append('*');
-    buf.append(Changeset.numToString(pool.putAttrib(atts[i])));
+    buf.append(exports.numToString(pool.putAttrib(atts[i])));
   }
   //print(att1+" / "+att2+" / "+buf.toString());
   return buf.toString();
 };
 
-Changeset._slicerZipperFunc = function(attOp, csOp, opOut, pool)
-{
+exports._slicerZipperFunc = function (attOp, csOp, opOut, pool) {
   // attOp is the op from the sequence that is being operated on, either an
-  // attribution string or the earlier of two changesets being composed.
+  // attribution string or the earlier of two exportss being composed.
   // pool can be null if definitely not needed.
   //print(csOp.toSource()+" "+attOp.toSource()+" "+opOut.toSource());
-  if (attOp.opcode == '-')
-  {
-    Changeset.copyOp(attOp, opOut);
+  if (attOp.opcode == '-') {
+    exports.copyOp(attOp, opOut);
     attOp.opcode = '';
-  }
-  else if (!attOp.opcode)
-  {
-    Changeset.copyOp(csOp, opOut);
+  } else if (!attOp.opcode) {
+    exports.copyOp(csOp, opOut);
     csOp.opcode = '';
-  }
-  else
-  {
-    switch (csOp.opcode)
-    {
+  } else {
+    switch (csOp.opcode) {
     case '-':
       {
-        if (csOp.chars <= attOp.chars)
-        {
+        if (csOp.chars <= attOp.chars) {
           // delete or delete part
-          if (attOp.opcode == '=')
-          {
+          if (attOp.opcode == '=') {
             opOut.opcode = '-';
             opOut.chars = csOp.chars;
             opOut.lines = csOp.lines;
@@ -1243,16 +961,12 @@ Changeset._slicerZipperFunc = function(attOp, csOp, opOut, pool)
           attOp.chars -= csOp.chars;
           attOp.lines -= csOp.lines;
           csOp.opcode = '';
-          if (!attOp.chars)
-          {
+          if (!attOp.chars) {
             attOp.opcode = '';
           }
-        }
-        else
-        {
+        } else {
           // delete and keep going
-          if (attOp.opcode == '=')
-          {
+          if (attOp.opcode == '=') {
             opOut.opcode = '-';
             opOut.chars = attOp.chars;
             opOut.lines = attOp.lines;
@@ -1267,34 +981,30 @@ Changeset._slicerZipperFunc = function(attOp, csOp, opOut, pool)
     case '+':
       {
         // insert
-        Changeset.copyOp(csOp, opOut);
+        exports.copyOp(csOp, opOut);
         csOp.opcode = '';
         break;
       }
     case '=':
       {
-        if (csOp.chars <= attOp.chars)
-        {
+        if (csOp.chars <= attOp.chars) {
           // keep or keep part
           opOut.opcode = attOp.opcode;
           opOut.chars = csOp.chars;
           opOut.lines = csOp.lines;
-          opOut.attribs = Changeset.composeAttributes(attOp.attribs, csOp.attribs, attOp.opcode == '=', pool);
+          opOut.attribs = exports.composeAttributes(attOp.attribs, csOp.attribs, attOp.opcode == '=', pool);
           csOp.opcode = '';
           attOp.chars -= csOp.chars;
           attOp.lines -= csOp.lines;
-          if (!attOp.chars)
-          {
+          if (!attOp.chars) {
             attOp.opcode = '';
           }
-        }
-        else
-        {
+        } else {
           // keep and keep going
           opOut.opcode = attOp.opcode;
           opOut.chars = attOp.chars;
           opOut.lines = attOp.lines;
-          opOut.attribs = Changeset.composeAttributes(attOp.attribs, csOp.attribs, attOp.opcode == '=', pool);
+          opOut.attribs = exports.composeAttributes(attOp.attribs, csOp.attribs, attOp.opcode == '=', pool);
           attOp.opcode = '';
           csOp.chars -= attOp.chars;
           csOp.lines -= attOp.lines;
@@ -1303,7 +1013,7 @@ Changeset._slicerZipperFunc = function(attOp, csOp, opOut, pool)
       }
     case '':
       {
-        Changeset.copyOp(attOp, opOut);
+        exports.copyOp(attOp, opOut);
         attOp.opcode = '';
         break;
       }
@@ -1311,190 +1021,155 @@ Changeset._slicerZipperFunc = function(attOp, csOp, opOut, pool)
   }
 };
 
-Changeset.applyToAttribution = function(cs, astr, pool)
-{
-  var unpacked = Changeset.unpack(cs);
+exports.applyToAttribution = function (cs, astr, pool) {
+  var unpacked = exports.unpack(cs);
 
-  return Changeset.applyZip(astr, 0, unpacked.ops, 0, function(op1, op2, opOut)
-  {
-    return Changeset._slicerZipperFunc(op1, op2, opOut, pool);
+  return exports.applyZip(astr, 0, unpacked.ops, 0, function (op1, op2, opOut) {
+    return exports._slicerZipperFunc(op1, op2, opOut, pool);
   });
 };
 
-/*Changeset.oneInsertedLineAtATimeOpIterator = function(opsStr, optStartIndex, charBank) {
-  var iter = Changeset.opIterator(opsStr, optStartIndex);
+/*exports.oneInsertedLineAtATimeOpIterator = function(opsStr, optStartIndex, charBank) {
+  var iter = exports.opIterator(opsStr, optStartIndex);
   var bankIndex = 0;
 
 };*/
 
-Changeset.mutateAttributionLines = function(cs, lines, pool)
-{
+exports.mutateAttributionLines = function (cs, lines, pool) {
   //dmesg(cs);
   //dmesg(lines.toSource()+" ->");
-  var unpacked = Changeset.unpack(cs);
-  var csIter = Changeset.opIterator(unpacked.ops);
+  var unpacked = exports.unpack(cs);
+  var csIter = exports.opIterator(unpacked.ops);
   var csBank = unpacked.charBank;
   var csBankIndex = 0;
   // treat the attribution lines as text lines, mutating a line at a time
-  var mut = Changeset.textLinesMutator(lines);
+  var mut = exports.textLinesMutator(lines);
 
   var lineIter = null;
 
-  function isNextMutOp()
-  {
+  function isNextMutOp() {
     return (lineIter && lineIter.hasNext()) || mut.hasMore();
   }
 
-  function nextMutOp(destOp)
-  {
-    if ((!(lineIter && lineIter.hasNext())) && mut.hasMore())
-    {
+  function nextMutOp(destOp) {
+    if ((!(lineIter && lineIter.hasNext())) && mut.hasMore()) {
       var line = mut.removeLines(1);
-      lineIter = Changeset.opIterator(line);
+      lineIter = exports.opIterator(line);
     }
-    if (lineIter && lineIter.hasNext())
-    {
+    if (lineIter && lineIter.hasNext()) {
       lineIter.next(destOp);
-    }
-    else
-    {
+    } else {
       destOp.opcode = '';
     }
   }
   var lineAssem = null;
 
-  function outputMutOp(op)
-  {
+  function outputMutOp(op) {
     //print("outputMutOp: "+op.toSource());
-    if (!lineAssem)
-    {
-      lineAssem = Changeset.mergingOpAssembler();
+    if (!lineAssem) {
+      lineAssem = exports.mergingOpAssembler();
     }
     lineAssem.append(op);
-    if (op.lines > 0)
-    {
-      Changeset.assert(op.lines == 1, "Can't have op.lines of ", op.lines, " in attribution lines");
+    if (op.lines > 0) {
+      exports.assert(op.lines == 1, "Can't have op.lines of ", op.lines, " in attribution lines");
       // ship it to the mut
       mut.insert(lineAssem.toString(), 1);
       lineAssem = null;
     }
   }
 
-  var csOp = Changeset.newOp();
-  var attOp = Changeset.newOp();
-  var opOut = Changeset.newOp();
-  while (csOp.opcode || csIter.hasNext() || attOp.opcode || isNextMutOp())
-  {
-    if ((!csOp.opcode) && csIter.hasNext())
-    {
+  var csOp = exports.newOp();
+  var attOp = exports.newOp();
+  var opOut = exports.newOp();
+  while (csOp.opcode || csIter.hasNext() || attOp.opcode || isNextMutOp()) {
+    if ((!csOp.opcode) && csIter.hasNext()) {
       csIter.next(csOp);
     }
     //print(csOp.toSource()+" "+attOp.toSource()+" "+opOut.toSource());
     //print(csOp.opcode+"/"+csOp.lines+"/"+csOp.attribs+"/"+lineAssem+"/"+lineIter+"/"+(lineIter?lineIter.hasNext():null));
     //print("csOp: "+csOp.toSource());
-    if ((!csOp.opcode) && (!attOp.opcode) && (!lineAssem) && (!(lineIter && lineIter.hasNext())))
-    {
+    if ((!csOp.opcode) && (!attOp.opcode) && (!lineAssem) && (!(lineIter && lineIter.hasNext()))) {
       break; // done
-    }
-    else if (csOp.opcode == '=' && csOp.lines > 0 && (!csOp.attribs) && (!attOp.opcode) && (!lineAssem) && (!(lineIter && lineIter.hasNext())))
-    {
+    } else if (csOp.opcode == '=' && csOp.lines > 0 && (!csOp.attribs) && (!attOp.opcode) && (!lineAssem) && (!(lineIter && lineIter.hasNext()))) {
       // skip multiple lines; this is what makes small changes not order of the document size
       mut.skipLines(csOp.lines);
       //print("skipped: "+csOp.lines);
       csOp.opcode = '';
-    }
-    else if (csOp.opcode == '+')
-    {
-      if (csOp.lines > 1)
-      {
+    } else if (csOp.opcode == '+') {
+      if (csOp.lines > 1) {
         var firstLineLen = csBank.indexOf('\n', csBankIndex) + 1 - csBankIndex;
-        Changeset.copyOp(csOp, opOut);
+        exports.copyOp(csOp, opOut);
         csOp.chars -= firstLineLen;
         csOp.lines--;
         opOut.lines = 1;
         opOut.chars = firstLineLen;
-      }
-      else
-      {
-        Changeset.copyOp(csOp, opOut);
+      } else {
+        exports.copyOp(csOp, opOut);
         csOp.opcode = '';
       }
       outputMutOp(opOut);
       csBankIndex += opOut.chars;
       opOut.opcode = '';
-    }
-    else
-    {
-      if ((!attOp.opcode) && isNextMutOp())
-      {
+    } else {
+      if ((!attOp.opcode) && isNextMutOp()) {
         nextMutOp(attOp);
       }
       //print("attOp: "+attOp.toSource());
-      Changeset._slicerZipperFunc(attOp, csOp, opOut, pool);
-      if (opOut.opcode)
-      {
+      exports._slicerZipperFunc(attOp, csOp, opOut, pool);
+      if (opOut.opcode) {
         outputMutOp(opOut);
         opOut.opcode = '';
       }
     }
   }
 
-  Changeset.assert(!lineAssem, "line assembler not finished");
+  exports.assert(!lineAssem, "line assembler not finished");
   mut.close();
 
   //dmesg("-> "+lines.toSource());
 };
 
-Changeset.joinAttributionLines = function(theAlines)
-{
-  var assem = Changeset.mergingOpAssembler();
-  for (var i = 0; i < theAlines.length; i++)
-  {
+exports.joinAttributionLines = function (theAlines) {
+  var assem = exports.mergingOpAssembler();
+  for (var i = 0; i < theAlines.length; i++) {
     var aline = theAlines[i];
-    var iter = Changeset.opIterator(aline);
-    while (iter.hasNext())
-    {
+    var iter = exports.opIterator(aline);
+    while (iter.hasNext()) {
       assem.append(iter.next());
     }
   }
   return assem.toString();
 };
 
-Changeset.splitAttributionLines = function(attrOps, text)
-{
-  var iter = Changeset.opIterator(attrOps);
-  var assem = Changeset.mergingOpAssembler();
+exports.splitAttributionLines = function (attrOps, text) {
+  var iter = exports.opIterator(attrOps);
+  var assem = exports.mergingOpAssembler();
   var lines = [];
   var pos = 0;
 
-  function appendOp(op)
-  {
+  function appendOp(op) {
     assem.append(op);
-    if (op.lines > 0)
-    {
+    if (op.lines > 0) {
       lines.push(assem.toString());
       assem.clear();
     }
     pos += op.chars;
   }
 
-  while (iter.hasNext())
-  {
+  while (iter.hasNext()) {
     var op = iter.next();
     var numChars = op.chars;
     var numLines = op.lines;
-    while (numLines > 1)
-    {
+    while (numLines > 1) {
       var newlineEnd = text.indexOf('\n', pos) + 1;
-      Changeset.assert(newlineEnd > 0, "newlineEnd <= 0 in splitAttributionLines");
+      exports.assert(newlineEnd > 0, "newlineEnd <= 0 in splitAttributionLines");
       op.chars = newlineEnd - pos;
       op.lines = 1;
       appendOp(op);
       numChars -= op.chars;
       numLines -= op.lines;
     }
-    if (numLines == 1)
-    {
+    if (numLines == 1) {
       op.chars = numChars;
       op.lines = 1;
     }
@@ -1504,149 +1179,121 @@ Changeset.splitAttributionLines = function(attrOps, text)
   return lines;
 };
 
-Changeset.splitTextLines = function(text)
-{
+exports.splitTextLines = function (text) {
   return text.match(/[^\n]*(?:\n|[^\n]$)/g);
 };
 
-Changeset.compose = function(cs1, cs2, pool)
-{
-  var unpacked1 = Changeset.unpack(cs1);
-  var unpacked2 = Changeset.unpack(cs2);
+exports.compose = function (cs1, cs2, pool) {
+  var unpacked1 = exports.unpack(cs1);
+  var unpacked2 = exports.unpack(cs2);
   var len1 = unpacked1.oldLen;
   var len2 = unpacked1.newLen;
-  Changeset.assert(len2 == unpacked2.oldLen, "mismatched composition");
+  exports.assert(len2 == unpacked2.oldLen, "mismatched composition");
   var len3 = unpacked2.newLen;
-  var bankIter1 = Changeset.stringIterator(unpacked1.charBank);
-  var bankIter2 = Changeset.stringIterator(unpacked2.charBank);
-  var bankAssem = Changeset.stringAssembler();
-
-  var newOps = Changeset.applyZip(unpacked1.ops, 0, unpacked2.ops, 0, function(op1, op2, opOut)
-  {
-    //var debugBuilder = Changeset.stringAssembler();
-    //debugBuilder.append(Changeset.opString(op1));
+  var bankIter1 = exports.stringIterator(unpacked1.charBank);
+  var bankIter2 = exports.stringIterator(unpacked2.charBank);
+  var bankAssem = exports.stringAssembler();
+
+  var newOps = exports.applyZip(unpacked1.ops, 0, unpacked2.ops, 0, function (op1, op2, opOut) {
+    //var debugBuilder = exports.stringAssembler();
+    //debugBuilder.append(exports.opString(op1));
     //debugBuilder.append(',');
-    //debugBuilder.append(Changeset.opString(op2));
+    //debugBuilder.append(exports.opString(op2));
     //debugBuilder.append(' / ');
     var op1code = op1.opcode;
     var op2code = op2.opcode;
-    if (op1code == '+' && op2code == '-')
-    {
+    if (op1code == '+' && op2code == '-') {
       bankIter1.skip(Math.min(op1.chars, op2.chars));
     }
-    Changeset._slicerZipperFunc(op1, op2, opOut, pool);
-    if (opOut.opcode == '+')
-    {
-      if (op2code == '+')
-      {
+    exports._slicerZipperFunc(op1, op2, opOut, pool);
+    if (opOut.opcode == '+') {
+      if (op2code == '+') {
         bankAssem.append(bankIter2.take(opOut.chars));
-      }
-      else
-      {
+      } else {
         bankAssem.append(bankIter1.take(opOut.chars));
       }
     }
 
-    //debugBuilder.append(Changeset.opString(op1));
+    //debugBuilder.append(exports.opString(op1));
     //debugBuilder.append(',');
-    //debugBuilder.append(Changeset.opString(op2));
+    //debugBuilder.append(exports.opString(op2));
     //debugBuilder.append(' -> ');
-    //debugBuilder.append(Changeset.opString(opOut));
+    //debugBuilder.append(exports.opString(opOut));
     //print(debugBuilder.toString());
   });
 
-  return Changeset.pack(len1, len3, newOps, bankAssem.toString());
+  return exports.pack(len1, len3, newOps, bankAssem.toString());
 };
 
-Changeset.attributeTester = function(attribPair, pool)
-{
+exports.attributeTester = function (attribPair, pool) {
   // returns a function that tests if a string of attributes
   // (e.g. *3*4) contains a given attribute key,value that
   // is already present in the pool.
-  if (!pool)
-  {
+  if (!pool) {
     return never;
   }
   var attribNum = pool.putAttrib(attribPair, true);
-  if (attribNum < 0)
-  {
+  if (attribNum < 0) {
     return never;
-  }
-  else
-  {
-    var re = new RegExp('\\*' + Changeset.numToString(attribNum) + '(?!\\w)');
-    return function(attribs)
-    {
+  } else {
+    var re = new RegExp('\\*' + exports.numToString(attribNum) + '(?!\\w)');
+    return function (attribs) {
       return re.test(attribs);
     };
   }
 
-  function never(attribs)
-  {
+  function never(attribs) {
     return false;
   }
 };
 
-Changeset.identity = function(N)
-{
-  return Changeset.pack(N, N, "", "");
+exports.identity = function (N) {
+  return exports.pack(N, N, "", "");
 };
 
-Changeset.makeSplice = function(oldFullText, spliceStart, numRemoved, newText, optNewTextAPairs, pool)
-{
+exports.makeSplice = function (oldFullText, spliceStart, numRemoved, newText, optNewTextAPairs, pool) {
   var oldLen = oldFullText.length;
 
-  if (spliceStart >= oldLen)
-  {
+  if (spliceStart >= oldLen) {
     spliceStart = oldLen - 1;
   }
-  if (numRemoved > oldFullText.length - spliceStart - 1)
-  {
+  if (numRemoved > oldFullText.length - spliceStart - 1) {
     numRemoved = oldFullText.length - spliceStart - 1;
   }
   var oldText = oldFullText.substring(spliceStart, spliceStart + numRemoved);
   var newLen = oldLen + newText.length - oldText.length;
 
-  var assem = Changeset.smartOpAssembler();
+  var assem = exports.smartOpAssembler();
   assem.appendOpWithText('=', oldFullText.substring(0, spliceStart));
   assem.appendOpWithText('-', oldText);
   assem.appendOpWithText('+', newText, optNewTextAPairs, pool);
   assem.endDocument();
-  return Changeset.pack(oldLen, newLen, assem.toString(), newText);
+  return exports.pack(oldLen, newLen, assem.toString(), newText);
 };
 
-Changeset.toSplices = function(cs)
-{
+exports.toSplices = function (cs) {
   // get a list of splices, [startChar, endChar, newText]
-  var unpacked = Changeset.unpack(cs);
+  var unpacked = exports.unpack(cs);
   var splices = [];
 
   var oldPos = 0;
-  var iter = Changeset.opIterator(unpacked.ops);
-  var charIter = Changeset.stringIterator(unpacked.charBank);
+  var iter = exports.opIterator(unpacked.ops);
+  var charIter = exports.stringIterator(unpacked.charBank);
   var inSplice = false;
-  while (iter.hasNext())
-  {
+  while (iter.hasNext()) {
     var op = iter.next();
-    if (op.opcode == '=')
-    {
+    if (op.opcode == '=') {
       oldPos += op.chars;
       inSplice = false;
-    }
-    else
-    {
-      if (!inSplice)
-      {
+    } else {
+      if (!inSplice) {
         splices.push([oldPos, oldPos, ""]);
         inSplice = true;
       }
-      if (op.opcode == '-')
-      {
+      if (op.opcode == '-') {
         oldPos += op.chars;
         splices[splices.length - 1][1] += op.chars;
-      }
-      else if (op.opcode == '+')
-      {
+      } else if (op.opcode == '+') {
         splices[splices.length - 1][2] += charIter.take(op.chars);
       }
     }
@@ -1655,56 +1302,40 @@ Changeset.toSplices = function(cs)
   return splices;
 };
 
-Changeset.characterRangeFollow = function(cs, startChar, endChar, insertionsAfter)
-{
+exports.characterRangeFollow = function (cs, startChar, endChar, insertionsAfter) {
   var newStartChar = startChar;
   var newEndChar = endChar;
-  var splices = Changeset.toSplices(cs);
+  var splices = exports.toSplices(cs);
   var lengthChangeSoFar = 0;
-  for (var i = 0; i < splices.length; i++)
-  {
+  for (var i = 0; i < splices.length; i++) {
     var splice = splices[i];
     var spliceStart = splice[0] + lengthChangeSoFar;
     var spliceEnd = splice[1] + lengthChangeSoFar;
     var newTextLength = splice[2].length;
     var thisLengthChange = newTextLength - (spliceEnd - spliceStart);
 
-    if (spliceStart <= newStartChar && spliceEnd >= newEndChar)
-    {
+    if (spliceStart <= newStartChar && spliceEnd >= newEndChar) {
       // splice fully replaces/deletes range
       // (also case that handles insertion at a collapsed selection)
-      if (insertionsAfter)
-      {
+      if (insertionsAfter) {
         newStartChar = newEndChar = spliceStart;
-      }
-      else
-      {
+      } else {
         newStartChar = newEndChar = spliceStart + newTextLength;
       }
-    }
-    else if (spliceEnd <= newStartChar)
-    {
+    } else if (spliceEnd <= newStartChar) {
       // splice is before range
       newStartChar += thisLengthChange;
       newEndChar += thisLengthChange;
-    }
-    else if (spliceStart >= newEndChar)
-    {
+    } else if (spliceStart >= newEndChar) {
       // splice is after range
-    }
-    else if (spliceStart >= newStartChar && spliceEnd <= newEndChar)
-    {
+    } else if (spliceStart >= newStartChar && spliceEnd <= newEndChar) {
       // splice is inside range
       newEndChar += thisLengthChange;
-    }
-    else if (spliceEnd < newEndChar)
-    {
+    } else if (spliceEnd < newEndChar) {
       // splice overlaps beginning of range
       newStartChar = spliceStart + newTextLength;
       newEndChar += thisLengthChange;
-    }
-    else
-    {
+    } else {
       // splice overlaps end of range
       newEndChar = spliceStart;
     }
@@ -1715,79 +1346,63 @@ Changeset.characterRangeFollow = function(cs, startChar, endChar, insertionsAfte
   return [newStartChar, newEndChar];
 };
 
-Changeset.moveOpsToNewPool = function(cs, oldPool, newPool)
-{
-  // works on changeset or attribution string
+exports.moveOpsToNewPool = function (cs, oldPool, newPool) {
+  // works on exports or attribution string
   var dollarPos = cs.indexOf('$');
-  if (dollarPos < 0)
-  {
+  if (dollarPos < 0) {
     dollarPos = cs.length;
   }
   var upToDollar = cs.substring(0, dollarPos);
   var fromDollar = cs.substring(dollarPos);
   // order of attribs stays the same
-  return upToDollar.replace(/\*([0-9a-z]+)/g, function(_, a)
-  {
-    var oldNum = Changeset.parseNum(a);
+  return upToDollar.replace(/\*([0-9a-z]+)/g, function (_, a) {
+    var oldNum = exports.parseNum(a);
     var pair = oldPool.getAttrib(oldNum);
     var newNum = newPool.putAttrib(pair);
-    return '*' + Changeset.numToString(newNum);
+    return '*' + exports.numToString(newNum);
   }) + fromDollar;
 };
 
-Changeset.makeAttribution = function(text)
-{
-  var assem = Changeset.smartOpAssembler();
+exports.makeAttribution = function (text) {
+  var assem = exports.smartOpAssembler();
   assem.appendOpWithText('+', text);
   return assem.toString();
 };
 
-// callable on a changeset, attribution string, or attribs property of an op
-Changeset.eachAttribNumber = function(cs, func)
-{
+// callable on a exports, attribution string, or attribs property of an op
+exports.eachAttribNumber = function (cs, func) {
   var dollarPos = cs.indexOf('$');
-  if (dollarPos < 0)
-  {
+  if (dollarPos < 0) {
     dollarPos = cs.length;
   }
   var upToDollar = cs.substring(0, dollarPos);
 
-  upToDollar.replace(/\*([0-9a-z]+)/g, function(_, a)
-  {
-    func(Changeset.parseNum(a));
+  upToDollar.replace(/\*([0-9a-z]+)/g, function (_, a) {
+    func(exports.parseNum(a));
     return '';
   });
 };
 
-// callable on a changeset, attribution string, or attribs property of an op,
+// callable on a exports, attribution string, or attribs property of an op,
 // though it may easily create adjacent ops that can be merged.
-Changeset.filterAttribNumbers = function(cs, filter)
-{
-  return Changeset.mapAttribNumbers(cs, filter);
+exports.filterAttribNumbers = function (cs, filter) {
+  return exports.mapAttribNumbers(cs, filter);
 };
 
-Changeset.mapAttribNumbers = function(cs, func)
-{
+exports.mapAttribNumbers = function (cs, func) {
   var dollarPos = cs.indexOf('$');
-  if (dollarPos < 0)
-  {
+  if (dollarPos < 0) {
     dollarPos = cs.length;
   }
   var upToDollar = cs.substring(0, dollarPos);
 
-  var newUpToDollar = upToDollar.replace(/\*([0-9a-z]+)/g, function(s, a)
-  {
-    var n = func(Changeset.parseNum(a));
-    if (n === true)
-    {
+  var newUpToDollar = upToDollar.replace(/\*([0-9a-z]+)/g, function (s, a) {
+    var n = func(exports.parseNum(a));
+    if (n === true) {
       return s;
-    }
-    else if ((typeof n) === "number")
-    {
-      return '*' + Changeset.numToString(n);
-    }
-    else
-    {
+    } else if ((typeof n) === "number") {
+      return '*' + exports.numToString(n);
+    } else {
       return '';
     }
   });
@@ -1795,108 +1410,88 @@ Changeset.mapAttribNumbers = function(cs, func)
   return newUpToDollar + cs.substring(dollarPos);
 };
 
-Changeset.makeAText = function(text, attribs)
-{
+exports.makeAText = function (text, attribs) {
   return {
     text: text,
-    attribs: (attribs || Changeset.makeAttribution(text))
+    attribs: (attribs || exports.makeAttribution(text))
   };
 };
 
-Changeset.applyToAText = function(cs, atext, pool)
-{
+exports.applyToAText = function (cs, atext, pool) {
   return {
-    text: Changeset.applyToText(cs, atext.text),
-    attribs: Changeset.applyToAttribution(cs, atext.attribs, pool)
+    text: exports.applyToText(cs, atext.text),
+    attribs: exports.applyToAttribution(cs, atext.attribs, pool)
   };
 };
 
-Changeset.cloneAText = function(atext)
-{
+exports.cloneAText = function (atext) {
   return {
     text: atext.text,
     attribs: atext.attribs
   };
 };
 
-Changeset.copyAText = function(atext1, atext2)
-{
+exports.copyAText = function (atext1, atext2) {
   atext2.text = atext1.text;
   atext2.attribs = atext1.attribs;
 };
 
-Changeset.appendATextToAssembler = function(atext, assem)
-{
+exports.appendATextToAssembler = function (atext, assem) {
   // intentionally skips last newline char of atext
-  var iter = Changeset.opIterator(atext.attribs);
-  var op = Changeset.newOp();
-  while (iter.hasNext())
-  {
+  var iter = exports.opIterator(atext.attribs);
+  var op = exports.newOp();
+  while (iter.hasNext()) {
     iter.next(op);
-    if (!iter.hasNext())
-    {
+    if (!iter.hasNext()) {
       // last op, exclude final newline
-      if (op.lines <= 1)
-      {
+      if (op.lines <= 1) {
         op.lines = 0;
         op.chars--;
-        if (op.chars)
-        {
+        if (op.chars) {
           assem.append(op);
         }
-      }
-      else
-      {
-        var nextToLastNewlineEnd = atext.text.lastIndexOf('\n', atext.text.length - 2) + 1;
+      } else {
+        var nextToLastNewlineEnd =
+        atext.text.lastIndexOf('\n', atext.text.length - 2) + 1;
         var lastLineLength = atext.text.length - nextToLastNewlineEnd - 1;
         op.lines--;
         op.chars -= (lastLineLength + 1);
         assem.append(op);
         op.lines = 0;
         op.chars = lastLineLength;
-        if (op.chars)
-        {
+        if (op.chars) {
           assem.append(op);
         }
       }
-    }
-    else
-    {
+    } else {
       assem.append(op);
     }
   }
 };
 
-Changeset.prepareForWire = function(cs, pool)
-{
-  var newPool = new AttribPool();
-  var newCs = Changeset.moveOpsToNewPool(cs, pool, newPool);
+exports.prepareForWire = function (cs, pool) {
+  var newPool = AttributePoolFactory.createAttributePool();;
+  var newCs = exports.moveOpsToNewPool(cs, pool, newPool);
   return {
     translated: newCs,
     pool: newPool
   };
 };
 
-Changeset.isIdentity = function(cs)
-{
-  var unpacked = Changeset.unpack(cs);
+exports.isIdentity = function (cs) {
+  var unpacked = exports.unpack(cs);
   return unpacked.ops == "" && unpacked.oldLen == unpacked.newLen;
 };
 
-Changeset.opAttributeValue = function(op, key, pool)
-{
-  return Changeset.attribsAttributeValue(op.attribs, key, pool);
+exports.opAttributeValue = function (op, key, pool) {
+  return exports.attribsAttributeValue(op.attribs, key, pool);
 };
 
-Changeset.attribsAttributeValue = function(attribs, key, pool)
-{
+exports.attribsAttributeValue = function (attribs, key, pool) {
   var value = '';
-  if (attribs)
-  {
-    Changeset.eachAttribNumber(attribs, function(n)
-    {
-      if (pool.getAttribKey(n) == key)
-      {
+  if (attribs) {
+    exports.eachAttribNumber(attribs, function (n) {
+      if (pool.getAttribKey(n) == key) {
         value = pool.getAttribValue(n);
       }
     });
@@ -1904,36 +1499,31 @@ Changeset.attribsAttributeValue = function(attribs, key, pool)
   return value;
 };
 
-Changeset.builder = function(oldLen)
-{
-  var assem = Changeset.smartOpAssembler();
-  var o = Changeset.newOp();
-  var charBank = Changeset.stringAssembler();
+exports.builder = function (oldLen) {
+  var assem = exports.smartOpAssembler();
+  var o = exports.newOp();
+  var charBank = exports.stringAssembler();
 
   var self = {
     // attribs are [[key1,value1],[key2,value2],...] or '*0*1...' (no pool needed in latter case)
-    keep: function(N, L, attribs, pool)
-    {
+    keep: function (N, L, attribs, pool) {
       o.opcode = '=';
-      o.attribs = (attribs && Changeset.makeAttribsString('=', attribs, pool)) || '';
+      o.attribs = (attribs && exports.makeAttribsString('=', attribs, pool)) || '';
       o.chars = N;
       o.lines = (L || 0);
       assem.append(o);
       return self;
     },
-    keepText: function(text, attribs, pool)
-    {
+    keepText: function (text, attribs, pool) {
       assem.appendOpWithText('=', text, attribs, pool);
       return self;
     },
-    insert: function(text, attribs, pool)
-    {
+    insert: function (text, attribs, pool) {
       assem.appendOpWithText('+', text, attribs, pool);
       charBank.append(text);
       return self;
     },
-    remove: function(N, L)
-    {
+    remove: function (N, L) {
       o.opcode = '-';
       o.attribs = '';
       o.chars = N;
@@ -1941,42 +1531,32 @@ Changeset.builder = function(oldLen)
       assem.append(o);
       return self;
     },
-    toString: function()
-    {
+    toString: function () {
       assem.endDocument();
       var newLen = oldLen + assem.getLengthChange();
-      return Changeset.pack(oldLen, newLen, assem.toString(), charBank.toString());
+      return exports.pack(oldLen, newLen, assem.toString(), charBank.toString());
     }
   };
 
   return self;
 };
 
-Changeset.makeAttribsString = function(opcode, attribs, pool)
-{
+exports.makeAttribsString = function (opcode, attribs, pool) {
   // makeAttribsString(opcode, '*3') or makeAttribsString(opcode, [['foo','bar']], myPool) work
-  if (!attribs)
-  {
+  if (!attribs) {
     return '';
-  }
-  else if ((typeof attribs) == "string")
-  {
+  } else if ((typeof attribs) == "string") {
     return attribs;
-  }
-  else if (pool && attribs && attribs.length)
-  {
-    if (attribs.length > 1)
-    {
+  } else if (pool && attribs && attribs.length) {
+    if (attribs.length > 1) {
       attribs = attribs.slice();
       attribs.sort();
     }
     var result = [];
-    for (var i = 0; i < attribs.length; i++)
-    {
+    for (var i = 0; i < attribs.length; i++) {
       var pair = attribs[i];
-      if (opcode == '=' || (opcode == '+' && pair[1]))
-      {
-        result.push('*' + Changeset.numToString(pool.putAttrib(pair)));
+      if (opcode == '=' || (opcode == '+' && pair[1])) {
+        result.push('*' + exports.numToString(pool.putAttrib(pair)));
       }
     }
     return result.join('');
@@ -1984,30 +1564,24 @@ Changeset.makeAttribsString = function(opcode, attribs, pool)
 };
 
 // like "substring" but on a single-line attribution string
-Changeset.subattribution = function(astr, start, optEnd)
-{
-  var iter = Changeset.opIterator(astr, 0);
-  var assem = Changeset.smartOpAssembler();
-  var attOp = Changeset.newOp();
-  var csOp = Changeset.newOp();
-  var opOut = Changeset.newOp();
-
-  function doCsOp()
-  {
-    if (csOp.chars)
-    {
-      while (csOp.opcode && (attOp.opcode || iter.hasNext()))
-      {
+exports.subattribution = function (astr, start, optEnd) {
+  var iter = exports.opIterator(astr, 0);
+  var assem = exports.smartOpAssembler();
+  var attOp = exports.newOp();
+  var csOp = exports.newOp();
+  var opOut = exports.newOp();
+
+  function doCsOp() {
+    if (csOp.chars) {
+      while (csOp.opcode && (attOp.opcode || iter.hasNext())) {
         if (!attOp.opcode) iter.next(attOp);
 
-        if (csOp.opcode && attOp.opcode && csOp.chars >= attOp.chars && attOp.lines > 0 && csOp.lines <= 0)
-        {
+        if (csOp.opcode && attOp.opcode && csOp.chars >= attOp.chars && attOp.lines > 0 && csOp.lines <= 0) {
           csOp.lines++;
         }
 
-        Changeset._slicerZipperFunc(attOp, csOp, opOut, null);
-        if (opOut.opcode)
-        {
+        exports._slicerZipperFunc(attOp, csOp, opOut, null);
+        if (opOut.opcode) {
           assem.append(opOut);
           opOut.opcode = '';
         }
@@ -2020,20 +1594,15 @@ Changeset.subattribution = function(astr, start, optEnd)
 
   doCsOp();
 
-  if (optEnd === undefined)
-  {
-    if (attOp.opcode)
-    {
+  if (optEnd === undefined) {
+    if (attOp.opcode) {
       assem.append(attOp);
     }
-    while (iter.hasNext())
-    {
+    while (iter.hasNext()) {
       iter.next(attOp);
       assem.append(attOp);
     }
-  }
-  else
-  {
+  } else {
     csOp.opcode = '=';
     csOp.chars = optEnd - start;
     doCsOp();
@@ -2042,57 +1611,39 @@ Changeset.subattribution = function(astr, start, optEnd)
   return assem.toString();
 };
 
-Changeset.inverse = function(cs, lines, alines, pool)
-{
-  // lines and alines are what the changeset is meant to apply to.
+exports.inverse = function (cs, lines, alines, pool) {
+  // lines and alines are what the exports is meant to apply to.
   // They may be arrays or objects with .get(i) and .length methods.
   // They include final newlines on lines.
 
-
-  function lines_get(idx)
-  {
-    if (lines.get)
-    {
+  function lines_get(idx) {
+    if (lines.get) {
       return lines.get(idx);
-    }
-    else
-    {
+    } else {
       return lines[idx];
     }
   }
 
-  function lines_length()
-  {
-    if ((typeof lines.length) == "number")
-    {
+  function lines_length() {
+    if ((typeof lines.length) == "number") {
       return lines.length;
-    }
-    else
-    {
+    } else {
       return lines.length();
     }
   }
 
-  function alines_get(idx)
-  {
-    if (alines.get)
-    {
+  function alines_get(idx) {
+    if (alines.get) {
       return alines.get(idx);
-    }
-    else
-    {
+    } else {
       return alines[idx];
     }
   }
 
-  function alines_length()
-  {
-    if ((typeof alines.length) == "number")
-    {
+  function alines_length() {
+    if ((typeof alines.length) == "number") {
       return alines.length;
-    }
-    else
-    {
+    } else {
       return alines.length();
     }
   }
@@ -2101,49 +1652,40 @@ Changeset.inverse = function(cs, lines, alines, pool)
   var curChar = 0;
   var curLineOpIter = null;
   var curLineOpIterLine;
-  var curLineNextOp = Changeset.newOp('+');
+  var curLineNextOp = exports.newOp('+');
 
-  var unpacked = Changeset.unpack(cs);
-  var csIter = Changeset.opIterator(unpacked.ops);
-  var builder = Changeset.builder(unpacked.newLen);
+  var unpacked = exports.unpack(cs);
+  var csIter = exports.opIterator(unpacked.ops);
+  var builder = exports.builder(unpacked.newLen);
 
-  function consumeAttribRuns(numChars, func /*(len, attribs, endsLine)*/ )
-  {
+  function consumeAttribRuns(numChars, func /*(len, attribs, endsLine)*/ ) {
 
-    if ((!curLineOpIter) || (curLineOpIterLine != curLine))
-    {
+    if ((!curLineOpIter) || (curLineOpIterLine != curLine)) {
       // create curLineOpIter and advance it to curChar
-      curLineOpIter = Changeset.opIterator(alines_get(curLine));
+      curLineOpIter = exports.opIterator(alines_get(curLine));
       curLineOpIterLine = curLine;
       var indexIntoLine = 0;
       var done = false;
-      while (!done)
-      {
+      while (!done) {
         curLineOpIter.next(curLineNextOp);
-        if (indexIntoLine + curLineNextOp.chars >= curChar)
-        {
+        if (indexIntoLine + curLineNextOp.chars >= curChar) {
           curLineNextOp.chars -= (curChar - indexIntoLine);
           done = true;
-        }
-        else
-        {
+        } else {
           indexIntoLine += curLineNextOp.chars;
         }
       }
     }
 
-    while (numChars > 0)
-    {
-      if ((!curLineNextOp.chars) && (!curLineOpIter.hasNext()))
-      {
+    while (numChars > 0) {
+      if ((!curLineNextOp.chars) && (!curLineOpIter.hasNext())) {
         curLine++;
         curChar = 0;
         curLineOpIterLine = curLine;
         curLineNextOp.chars = 0;
-        curLineOpIter = Changeset.opIterator(alines_get(curLine));
+        curLineOpIter = exports.opIterator(alines_get(curLine));
       }
-      if (!curLineNextOp.chars)
-      {
+      if (!curLineNextOp.chars) {
         curLineOpIter.next(curLineNextOp);
       }
       var charsToUse = Math.min(numChars, curLineNextOp.chars);
@@ -2153,45 +1695,34 @@ Changeset.inverse = function(cs, lines, alines, pool)
       curChar += charsToUse;
     }
 
-    if ((!curLineNextOp.chars) && (!curLineOpIter.hasNext()))
-    {
+    if ((!curLineNextOp.chars) && (!curLineOpIter.hasNext())) {
       curLine++;
       curChar = 0;
     }
   }
 
-  function skip(N, L)
-  {
-    if (L)
-    {
+  function skip(N, L) {
+    if (L) {
       curLine += L;
       curChar = 0;
-    }
-    else
-    {
-      if (curLineOpIter && curLineOpIterLine == curLine)
-      {
-        consumeAttribRuns(N, function()
-        {});
-      }
-      else
-      {
+    } else {
+      if (curLineOpIter && curLineOpIterLine == curLine) {
+        consumeAttribRuns(N, function () {});
+      } else {
         curChar += N;
       }
     }
   }
 
-  function nextText(numChars)
-  {
+  function nextText(numChars) {
     var len = 0;
-    var assem = Changeset.stringAssembler();
+    var assem = exports.stringAssembler();
     var firstString = lines_get(curLine).substring(curChar);
     len += firstString.length;
     assem.append(firstString);
 
     var lineNum = curLine + 1;
-    while (len < numChars)
-    {
+    while (len < numChars) {
       var nextString = lines_get(lineNum);
       len += nextString.length;
       assem.append(nextString);
@@ -2201,13 +1732,10 @@ Changeset.inverse = function(cs, lines, alines, pool)
     return assem.toString().substring(0, numChars);
   }
 
-  function cachedStrFunc(func)
-  {
+  function cachedStrFunc(func) {
     var cache = {};
-    return function(s)
-    {
-      if (!cache[s])
-      {
+    return function (s) {
+      if (!cache[s]) {
         cache[s] = func(s);
       }
       return cache[s];
@@ -2216,192 +1744,140 @@ Changeset.inverse = function(cs, lines, alines, pool)
 
   var attribKeys = [];
   var attribValues = [];
-  while (csIter.hasNext())
-  {
+  while (csIter.hasNext()) {
     var csOp = csIter.next();
-    if (csOp.opcode == '=')
-    {
-      if (csOp.attribs)
-      {
+    if (csOp.opcode == '=') {
+      if (csOp.attribs) {
         attribKeys.length = 0;
         attribValues.length = 0;
-        Changeset.eachAttribNumber(csOp.attribs, function(n)
-        {
+        exports.eachAttribNumber(csOp.attribs, function (n) {
           attribKeys.push(pool.getAttribKey(n));
           attribValues.push(pool.getAttribValue(n));
         });
-        var undoBackToAttribs = cachedStrFunc(function(attribs)
-        {
+        var undoBackToAttribs = cachedStrFunc(function (attribs) {
           var backAttribs = [];
-          for (var i = 0; i < attribKeys.length; i++)
-          {
+          for (var i = 0; i < attribKeys.length; i++) {
             var appliedKey = attribKeys[i];
             var appliedValue = attribValues[i];
-            var oldValue = Changeset.attribsAttributeValue(attribs, appliedKey, pool);
-            if (appliedValue != oldValue)
-            {
+            var oldValue = exports.attribsAttributeValue(attribs, appliedKey, pool);
+            if (appliedValue != oldValue) {
               backAttribs.push([appliedKey, oldValue]);
             }
           }
-          return Changeset.makeAttribsString('=', backAttribs, pool);
+          return exports.makeAttribsString('=', backAttribs, pool);
         });
-        consumeAttribRuns(csOp.chars, function(len, attribs, endsLine)
-        {
+        consumeAttribRuns(csOp.chars, function (len, attribs, endsLine) {
           builder.keep(len, endsLine ? 1 : 0, undoBackToAttribs(attribs));
         });
-      }
-      else
-      {
+      } else {
         skip(csOp.chars, csOp.lines);
         builder.keep(csOp.chars, csOp.lines);
       }
-    }
-    else if (csOp.opcode == '+')
-    {
+    } else if (csOp.opcode == '+') {
       builder.remove(csOp.chars, csOp.lines);
-    }
-    else if (csOp.opcode == '-')
-    {
+    } else if (csOp.opcode == '-') {
       var textBank = nextText(csOp.chars);
       var textBankIndex = 0;
-      consumeAttribRuns(csOp.chars, function(len, attribs, endsLine)
-      {
+      consumeAttribRuns(csOp.chars, function (len, attribs, endsLine) {
         builder.insert(textBank.substr(textBankIndex, len), attribs);
         textBankIndex += len;
       });
     }
   }
 
-  return Changeset.checkRep(builder.toString());
+  return exports.checkRep(builder.toString());
 };
 
 // %CLIENT FILE ENDS HERE%
-Changeset.follow = function(cs1, cs2, reverseInsertOrder, pool)
-{
-  var unpacked1 = Changeset.unpack(cs1);
-  var unpacked2 = Changeset.unpack(cs2);
+exports.follow = function (cs1, cs2, reverseInsertOrder, pool) {
+  var unpacked1 = exports.unpack(cs1);
+  var unpacked2 = exports.unpack(cs2);
   var len1 = unpacked1.oldLen;
   var len2 = unpacked2.oldLen;
-  Changeset.assert(len1 == len2, "mismatched follow");
-  var chars1 = Changeset.stringIterator(unpacked1.charBank);
-  var chars2 = Changeset.stringIterator(unpacked2.charBank);
+  exports.assert(len1 == len2, "mismatched follow");
+  var chars1 = exports.stringIterator(unpacked1.charBank);
+  var chars2 = exports.stringIterator(unpacked2.charBank);
 
   var oldLen = unpacked1.newLen;
   var oldPos = 0;
   var newLen = 0;
 
-  var hasInsertFirst = Changeset.attributeTester(['insertorder', 'first'], pool);
+  var hasInsertFirst = exports.attributeTester(['insertorder', 'first'], pool);
 
-  var newOps = Changeset.applyZip(unpacked1.ops, 0, unpacked2.ops, 0, function(op1, op2, opOut)
-  {
-    if (op1.opcode == '+' || op2.opcode == '+')
-    {
+  var newOps = exports.applyZip(unpacked1.ops, 0, unpacked2.ops, 0, function (op1, op2, opOut) {
+    if (op1.opcode == '+' || op2.opcode == '+') {
       var whichToDo;
-      if (op2.opcode != '+')
-      {
+      if (op2.opcode != '+') {
         whichToDo = 1;
-      }
-      else if (op1.opcode != '+')
-      {
+      } else if (op1.opcode != '+') {
         whichToDo = 2;
-      }
-      else
-      {
+      } else {
         // both +
         var firstChar1 = chars1.peek(1);
         var firstChar2 = chars2.peek(1);
         var insertFirst1 = hasInsertFirst(op1.attribs);
         var insertFirst2 = hasInsertFirst(op2.attribs);
-        if (insertFirst1 && !insertFirst2)
-        {
+        if (insertFirst1 && !insertFirst2) {
           whichToDo = 1;
-        }
-        else if (insertFirst2 && !insertFirst1)
-        {
+        } else if (insertFirst2 && !insertFirst1) {
           whichToDo = 2;
         }
         // insert string that doesn't start with a newline first so as not to break up lines
-        else if (firstChar1 == '\n' && firstChar2 != '\n')
-        {
+        else if (firstChar1 == '\n' && firstChar2 != '\n') {
           whichToDo = 2;
-        }
-        else if (firstChar1 != '\n' && firstChar2 == '\n')
-        {
+        } else if (firstChar1 != '\n' && firstChar2 == '\n') {
           whichToDo = 1;
         }
         // break symmetry:
-        else if (reverseInsertOrder)
-        {
+        else if (reverseInsertOrder) {
           whichToDo = 2;
-        }
-        else
-        {
+        } else {
           whichToDo = 1;
         }
       }
-      if (whichToDo == 1)
-      {
+      if (whichToDo == 1) {
         chars1.skip(op1.chars);
         opOut.opcode = '=';
         opOut.lines = op1.lines;
         opOut.chars = op1.chars;
         opOut.attribs = '';
         op1.opcode = '';
-      }
-      else
-      {
+      } else {
         // whichToDo == 2
         chars2.skip(op2.chars);
-        Changeset.copyOp(op2, opOut);
+        exports.copyOp(op2, opOut);
         op2.opcode = '';
       }
-    }
-    else if (op1.opcode == '-')
-    {
-      if (!op2.opcode)
-      {
+    } else if (op1.opcode == '-') {
+      if (!op2.opcode) {
         op1.opcode = '';
-      }
-      else
-      {
-        if (op1.chars <= op2.chars)
-        {
+      } else {
+        if (op1.chars <= op2.chars) {
           op2.chars -= op1.chars;
           op2.lines -= op1.lines;
           op1.opcode = '';
-          if (!op2.chars)
-          {
+          if (!op2.chars) {
             op2.opcode = '';
           }
-        }
-        else
-        {
+        } else {
           op1.chars -= op2.chars;
           op1.lines -= op2.lines;
           op2.opcode = '';
         }
       }
-    }
-    else if (op2.opcode == '-')
-    {
-      Changeset.copyOp(op2, opOut);
-      if (!op1.opcode)
-      {
+    } else if (op2.opcode == '-') {
+      exports.copyOp(op2, opOut);
+      if (!op1.opcode) {
         op2.opcode = '';
-      }
-      else if (op2.chars <= op1.chars)
-      {
+      } else if (op2.chars <= op1.chars) {
         // delete part or all of a keep
         op1.chars -= op2.chars;
         op1.lines -= op2.lines;
         op2.opcode = '';
-        if (!op1.chars)
-        {
+        if (!op1.chars) {
           op1.opcode = '';
         }
-      }
-      else
-      {
+      } else {
         // delete all of a keep, and keep going
         opOut.lines = op1.lines;
         opOut.chars = op1.chars;
@@ -2409,36 +1885,26 @@ Changeset.follow = function(cs1, cs2, reverseInsertOrder, pool)
         op2.chars -= op1.chars;
         op1.opcode = '';
       }
-    }
-    else if (!op1.opcode)
-    {
-      Changeset.copyOp(op2, opOut);
+    } else if (!op1.opcode) {
+      exports.copyOp(op2, opOut);
       op2.opcode = '';
-    }
-    else if (!op2.opcode)
-    {
-      Changeset.copyOp(op1, opOut);
+    } else if (!op2.opcode) {
+      exports.copyOp(op1, opOut);
       op1.opcode = '';
-    }
-    else
-    {
+    } else {
       // both keeps
       opOut.opcode = '=';
-      opOut.attribs = Changeset.followAttributes(op1.attribs, op2.attribs, pool);
-      if (op1.chars <= op2.chars)
-      {
+      opOut.attribs = exports.followAttributes(op1.attribs, op2.attribs, pool);
+      if (op1.chars <= op2.chars) {
         opOut.chars = op1.chars;
         opOut.lines = op1.lines;
         op2.chars -= op1.chars;
         op2.lines -= op1.lines;
         op1.opcode = '';
-        if (!op2.chars)
-        {
+        if (!op2.chars) {
           op2.opcode = '';
         }
-      }
-      else
-      {
+      } else {
         opOut.chars = op2.chars;
         opOut.lines = op2.lines;
         op1.chars -= op2.chars;
@@ -2446,8 +1912,7 @@ Changeset.follow = function(cs1, cs2, reverseInsertOrder, pool)
         op2.opcode = '';
       }
     }
-    switch (opOut.opcode)
-    {
+    switch (opOut.opcode) {
     case '=':
       oldPos += opOut.chars;
       newLen += opOut.chars;
@@ -2462,11 +1927,10 @@ Changeset.follow = function(cs1, cs2, reverseInsertOrder, pool)
   });
   newLen += oldLen - oldPos;
 
-  return Changeset.pack(oldLen, newLen, newOps, unpacked2.charBank);
+  return exports.pack(oldLen, newLen, newOps, unpacked2.charBank);
 };
 
-Changeset.followAttributes = function(att1, att2, pool)
-{
+exports.followAttributes = function (att1, att2, pool) {
   // The merge of two sets of attribute changes to the same text
   // takes the lexically-earlier value if there are two values
   // for the same key.  Otherwise, all key/value changes from
@@ -2476,21 +1940,16 @@ Changeset.followAttributes = function(att1, att2, pool)
   if ((!att2) || (!pool)) return '';
   if (!att1) return att2;
   var atts = [];
-  att2.replace(/\*([0-9a-z]+)/g, function(_, a)
-  {
-    atts.push(pool.getAttrib(Changeset.parseNum(a)));
+  att2.replace(/\*([0-9a-z]+)/g, function (_, a) {
+    atts.push(pool.getAttrib(exports.parseNum(a)));
     return '';
   });
-  att1.replace(/\*([0-9a-z]+)/g, function(_, a)
-  {
-    var pair1 = pool.getAttrib(Changeset.parseNum(a));
-    for (var i = 0; i < atts.length; i++)
-    {
+  att1.replace(/\*([0-9a-z]+)/g, function (_, a) {
+    var pair1 = pool.getAttrib(exports.parseNum(a));
+    for (var i = 0; i < atts.length; i++) {
       var pair2 = atts[i];
-      if (pair1[0] == pair2[0])
-      {
-        if (pair1[1] <= pair2[1])
-        {
+      if (pair1[0] == pair2[0]) {
+        if (pair1[1] <= pair2[1]) {
           // winner of merge is pair1, delete this attribute
           atts.splice(i, 1);
         }
@@ -2500,14 +1959,10 @@ Changeset.followAttributes = function(att1, att2, pool)
     return '';
   });
   // we've only removed attributes, so they're already sorted
-  var buf = Changeset.stringAssembler();
-  for (var i = 0; i < atts.length; i++)
-  {
+  var buf = exports.stringAssembler();
+  for (var i = 0; i < atts.length; i++) {
     buf.append('*');
-    buf.append(Changeset.numToString(pool.putAttrib(atts[i])));
+    buf.append(exports.numToString(pool.putAttrib(atts[i])));
   }
   return buf.toString();
 };
-
-exports.Changeset = Changeset;
-exports.AttribPool = AttribPool;
diff --git a/static/js/ace2_common.js b/static/js/ace2_common.js
index 1ce7810a..b4c72a92 100644
--- a/static/js/ace2_common.js
+++ b/static/js/ace2_common.js
@@ -20,6 +20,7 @@
  * limitations under the License.
  */
 
+var Security = require('/security');
 
 function isNodeText(node)
 {
@@ -137,14 +138,7 @@ function binarySearchInfinite(expectedLength, func)
 
 function htmlPrettyEscape(str)
 {
-  return str.replace(/[&"<>]/g, function (c) {
-    return {
-      '&': '&amp;',
-      '"': '&quot;',
-      '<': '&lt;',
-      '>': '&gt;'
-    }[c] || c;
-  }).replace(/\r?\n/g, '\\n');
+  return Security.escapeHTML(str).replace(/\r?\n/g, '\\n');
 }
 
 exports.isNodeText = isNodeText;
diff --git a/static/js/ace2_inner.js b/static/js/ace2_inner.js
index 31d4dac9..d2113574 100644
--- a/static/js/ace2_inner.js
+++ b/static/js/ace2_inner.js
@@ -42,8 +42,8 @@ var colorutils = require('/colorutils').colorutils;
 var makeContentCollector = require('/contentcollector').makeContentCollector;
 var makeCSSManager = require('/cssmanager').makeCSSManager;
 var domline = require('/domline').domline;
-var AttribPool = require('/easysync2').AttribPool;
-var Changeset = require('/easysync2').Changeset;
+var AttribPool = require('/AttributePoolFactory').createAttributePool;
+var Changeset = require('/Changeset');
 var linestylefilter = require('/linestylefilter').linestylefilter;
 var newSkipList = require('/skiplist').newSkipList;
 var undoModule = require('/undomodule').undoModule;
diff --git a/static/js/broadcast.js b/static/js/broadcast.js
index 020f47e7..4a7b0168 100644
--- a/static/js/broadcast.js
+++ b/static/js/broadcast.js
@@ -20,11 +20,11 @@
  * limitations under the License.
  */
 
-var makeCSSManager = require('/cssmanager_client').makeCSSManager;
-var domline = require('/domline_client').domline;
-var Changeset = require('/easysync2_client').Changeset;
-var AttribPool = require('/easysync2_client').AttribPool;
-var linestylefilter = require('/linestylefilter_client').linestylefilter;
+var makeCSSManager = require('/cssmanager').makeCSSManager;
+var domline = require('/domline').domline;
+var AttribPool = require('/AttributePoolFactory').createAttributePool;
+var Changeset = require('/Changeset');
+var linestylefilter = require('/linestylefilter').linestylefilter;
 var colorutils = require('/colorutils').colorutils;
 
 // These parameters were global, now they are injected. A reference to the
diff --git a/static/js/changesettracker.js b/static/js/changesettracker.js
index 7b0fb3e4..e34dc107 100644
--- a/static/js/changesettracker.js
+++ b/static/js/changesettracker.js
@@ -20,8 +20,8 @@
  * limitations under the License.
  */
 
-var Changeset = require('/easysync2').Changeset;
-var AttribPool = require('/easysync2').AttribPool;
+var AttribPool = require('/AttributePoolFactory').createAttributePool;
+var Changeset = require('/Changeset');
 
 function makeChangesetTracker(scheduler, apool, aceCallbacksProvider)
 {
diff --git a/static/js/contentcollector.js b/static/js/contentcollector.js
index 0437ccd7..96dc4b7d 100644
--- a/static/js/contentcollector.js
+++ b/static/js/contentcollector.js
@@ -25,7 +25,7 @@
 
 var _MAX_LIST_LEVEL = 8;
 
-var Changeset = require('/easysync2').Changeset
+var Changeset = require('/Changeset');
 var plugins = require('/plugins').plugins;
 
 function sanitizeUnicode(s)
diff --git a/static/js/cssmanager_client.js b/static/js/cssmanager_client.js
deleted file mode 100644
index 6d9d989e..00000000
--- a/static/js/cssmanager_client.js
+++ /dev/null
@@ -1,118 +0,0 @@
-/**
- * This code is mostly from the old Etherpad. Please help us to comment this code. 
- * This helps other people to understand this code better and helps them to improve it.
- * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
- */
-
-// DO NOT EDIT THIS FILE, edit infrastructure/ace/www/cssmanager.js
-/**
- * Copyright 2009 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS-IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-function makeCSSManager(emptyStylesheetTitle)
-{
-
-  function getSheetByTitle(title)
-  {
-    var allSheets = document.styleSheets;
-    for (var i = 0; i < allSheets.length; i++)
-    {
-      var s = allSheets[i];
-      if (s.title == title)
-      {
-        return s;
-      }
-    }
-    return null;
-  }
-
-/*function getSheetTagByTitle(title) {
-    var allStyleTags = document.getElementsByTagName("style");
-    for(var i=0;i<allStyleTags.length;i++) {
-      var t = allStyleTags[i];
-      if (t.title == title) {
-	return t;
-      }
-    }
-    return null;
-  }*/
-
-  var browserSheet = getSheetByTitle(emptyStylesheetTitle);
-  //var browserTag = getSheetTagByTitle(emptyStylesheetTitle);
-
-  function browserRules()
-  {
-    return (browserSheet.cssRules || browserSheet.rules);
-  }
-
-  function browserDeleteRule(i)
-  {
-    if (browserSheet.deleteRule) browserSheet.deleteRule(i);
-    else browserSheet.removeRule(i);
-  }
-
-  function browserInsertRule(i, selector)
-  {
-    if (browserSheet.insertRule) browserSheet.insertRule(selector + ' {}', i);
-    else browserSheet.addRule(selector, null, i);
-  }
-  var selectorList = [];
-
-  function indexOfSelector(selector)
-  {
-    for (var i = 0; i < selectorList.length; i++)
-    {
-      if (selectorList[i] == selector)
-      {
-        return i;
-      }
-    }
-    return -1;
-  }
-
-  function selectorStyle(selector)
-  {
-    var i = indexOfSelector(selector);
-    if (i < 0)
-    {
-      // add selector
-      browserInsertRule(0, selector);
-      selectorList.splice(0, 0, selector);
-      i = 0;
-    }
-    return browserRules().item(i).style;
-  }
-
-  function removeSelectorStyle(selector)
-  {
-    var i = indexOfSelector(selector);
-    if (i >= 0)
-    {
-      browserDeleteRule(i);
-      selectorList.splice(i, 1);
-    }
-  }
-
-  return {
-    selectorStyle: selectorStyle,
-    removeSelectorStyle: removeSelectorStyle,
-    info: function()
-    {
-      return selectorList.length + ":" + browserRules().length;
-    }
-  };
-}
-
-exports.makeCSSManager = makeCSSManager;
diff --git a/static/js/domline.js b/static/js/domline.js
index 8d8c2ea9..15528bf7 100644
--- a/static/js/domline.js
+++ b/static/js/domline.js
@@ -26,6 +26,7 @@
 // requires: plugins
 // requires: undefined
 
+var Security = require('/security');
 var plugins = require('/plugins').plugins;
 var map = require('/ace2_common').map;
 
@@ -103,17 +104,17 @@ domline.createDomLine = function(nonEmpty, doesWrap, optBrowser, optDocument)
       if (listType)
       {
         listType = listType[1];
-        start = start?'start="'+start[1]+'"':'';
+        start = start?'start="'+Security.escapeHTMLAttribute(start[1])+'"':'';
         if (listType)
         {
           if(listType.indexOf("number") < 0)
           {
-            preHtml = '<ul class="list-' + listType + '"><li>';
+            preHtml = '<ul class="list-' + Security.escapeHTMLAttribute(listType) + '"><li>';
             postHtml = '</li></ul>';
           }
           else
           {
-            preHtml = '<ol '+start+' class="list-' + listType + '"><li>';
+            preHtml = '<ol '+start+' class="list-' + Security.escapeHTMLAttribute(listType) + '"><li>';
             postHtml = '</li></ol>';
           }
         }
@@ -168,7 +169,7 @@ domline.createDomLine = function(nonEmpty, doesWrap, optBrowser, optDocument)
         {
           href = "http://"+href;
         }
-        extraOpenTags = extraOpenTags + '<a href="' + domline.escapeHTML(href) + '">';
+        extraOpenTags = extraOpenTags + '<a href="' + Security.escapeHTMLAttribute(href) + '">';
         extraCloseTags = '</a>' + extraCloseTags;
       }
       if (simpleTags)
@@ -178,7 +179,7 @@ domline.createDomLine = function(nonEmpty, doesWrap, optBrowser, optDocument)
         simpleTags.reverse();
         extraCloseTags = '</' + simpleTags.join('></') + '>' + extraCloseTags;
       }
-      html.push('<span class="', cls || '', '">', extraOpenTags, perTextNodeProcess(domline.escapeHTML(txt)), extraCloseTags, '</span>');
+      html.push('<span class="', Security.escapeHTMLAttribute(cls || ''), '">', extraOpenTags, perTextNodeProcess(Security.escapeHTML(txt)), extraCloseTags, '</span>');
     }
   };
   result.clearSpans = function()
@@ -224,27 +225,6 @@ domline.createDomLine = function(nonEmpty, doesWrap, optBrowser, optDocument)
   return result;
 };
 
-domline.escapeHTML = function(s)
-{
-  var re = /[&<>'"]/g;
-  /']/; // stupid indentation thing
-  if (!re.MAP)
-  {
-    // persisted across function calls!
-    re.MAP = {
-      '&': '&amp;',
-      '<': '&lt;',
-      '>': '&gt;',
-      '"': '&quot;',
-      "'": '&#39;'
-    };
-  }
-  return s.replace(re, function(c)
-  {
-    return re.MAP[c];
-  });
-};
-
 domline.processSpaces = function(s, doesWrap)
 {
   if (s.indexOf("<") < 0 && !doesWrap)
diff --git a/static/js/domline_client.js b/static/js/domline_client.js
deleted file mode 100644
index 87b6ed55..00000000
--- a/static/js/domline_client.js
+++ /dev/null
@@ -1,309 +0,0 @@
-/**
- * This code is mostly from the old Etherpad. Please help us to comment this code. 
- * This helps other people to understand this code better and helps them to improve it.
- * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
- */
-
-// DO NOT EDIT THIS FILE, edit infrastructure/ace/www/domline.js
-// THIS FILE IS ALSO AN APPJET MODULE: etherpad.collab.ace.domline
-/**
- * Copyright 2009 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS-IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-// requires: top
-// requires: plugins
-// requires: undefined
-
-var plugins = require('/plugins').plugins;
-var map = require('/ace2_common').map;
-
-var domline = {};
-domline.noop = function()
-{};
-domline.identity = function(x)
-{
-  return x;
-};
-
-domline.addToLineClass = function(lineClass, cls)
-{
-  // an "empty span" at any point can be used to add classes to
-  // the line, using line:className.  otherwise, we ignore
-  // the span.
-  cls.replace(/\S+/g, function(c)
-  {
-    if (c.indexOf("line:") == 0)
-    {
-      // add class to line
-      lineClass = (lineClass ? lineClass + ' ' : '') + c.substring(5);
-    }
-  });
-  return lineClass;
-}
-
-// if "document" is falsy we don't create a DOM node, just
-// an object with innerHTML and className
-domline.createDomLine = function(nonEmpty, doesWrap, optBrowser, optDocument)
-{
-  var result = {
-    node: null,
-    appendSpan: domline.noop,
-    prepareForAdd: domline.noop,
-    notifyAdded: domline.noop,
-    clearSpans: domline.noop,
-    finishUpdate: domline.noop,
-    lineMarker: 0
-  };
-
-  var browser = (optBrowser || {});
-  var document = optDocument;
-
-  if (document)
-  {
-    result.node = document.createElement("div");
-  }
-  else
-  {
-    result.node = {
-      innerHTML: '',
-      className: ''
-    };
-  }
-
-  var html = [];
-  var preHtml, postHtml;
-  var curHTML = null;
-
-  function processSpaces(s)
-  {
-    return domline.processSpaces(s, doesWrap);
-  }
-  var identity = domline.identity;
-  var perTextNodeProcess = (doesWrap ? identity : processSpaces);
-  var perHtmlLineProcess = (doesWrap ? processSpaces : identity);
-  var lineClass = 'ace-line';
-  result.appendSpan = function(txt, cls)
-  {
-    if (cls.indexOf('list') >= 0)
-    {
-      var listType = /(?:^| )list:(\S+)/.exec(cls);
-      var start = /(?:^| )start:(\S+)/.exec(cls);
-      if (listType)
-      {
-        listType = listType[1];
-        start = start?'start="'+start[1]+'"':'';
-        if (listType)
-        {
-          if(listType.indexOf("number") < 0)
-          {
-            preHtml = '<ul class="list-' + listType + '"><li>';
-            postHtml = '</li></ul>';
-          }
-          else
-          {
-            preHtml = '<ol '+start+' class="list-' + listType + '"><li>';
-            postHtml = '</li></ol>';
-          }
-        }
-        result.lineMarker += txt.length;
-        return; // don't append any text
-      }
-    }
-    var href = null;
-    var simpleTags = null;
-    if (cls.indexOf('url') >= 0)
-    {
-      cls = cls.replace(/(^| )url:(\S+)/g, function(x0, space, url)
-      {
-        href = url;
-        return space + "url";
-      });
-    }
-    if (cls.indexOf('tag') >= 0)
-    {
-      cls = cls.replace(/(^| )tag:(\S+)/g, function(x0, space, tag)
-      {
-        if (!simpleTags) simpleTags = [];
-        simpleTags.push(tag.toLowerCase());
-        return space + tag;
-      });
-    }
-
-    var extraOpenTags = "";
-    var extraCloseTags = "";
-
-    var plugins_ = plugins;
-
-    map(plugins_.callHook("aceCreateDomLine", {
-      domline: domline,
-      cls: cls
-    }), function(modifier)
-    {
-      cls = modifier.cls;
-      extraOpenTags = extraOpenTags + modifier.extraOpenTags;
-      extraCloseTags = modifier.extraCloseTags + extraCloseTags;
-    });
-
-    if ((!txt) && cls)
-    {
-      lineClass = domline.addToLineClass(lineClass, cls);
-    }
-    else if (txt)
-    {
-      if (href)
-      {
-        if(!~href.indexOf("http")) // if the url doesn't include http or https etc prefix it.
-        {
-          href = "http://"+href;
-        }
-        extraOpenTags = extraOpenTags + '<a href="' + href.replace(/\"/g, '&quot;') + '">';
-        extraCloseTags = '</a>' + extraCloseTags;
-      }
-      if (simpleTags)
-      {
-        simpleTags.sort();
-        extraOpenTags = extraOpenTags + '<' + simpleTags.join('><') + '>';
-        simpleTags.reverse();
-        extraCloseTags = '</' + simpleTags.join('></') + '>' + extraCloseTags;
-      }
-      html.push('<span class="', cls || '', '">', extraOpenTags, perTextNodeProcess(domline.escapeHTML(txt)), extraCloseTags, '</span>');
-    }
-  };
-  result.clearSpans = function()
-  {
-    html = [];
-    lineClass = ''; // non-null to cause update
-    result.lineMarker = 0;
-  };
-
-  function writeHTML()
-  {
-    var newHTML = perHtmlLineProcess(html.join(''));
-    if (!newHTML)
-    {
-      if ((!document) || (!optBrowser))
-      {
-        newHTML += '&nbsp;';
-      }
-      else if (!browser.msie)
-      {
-        newHTML += '<br/>';
-      }
-    }
-    if (nonEmpty)
-    {
-      newHTML = (preHtml || '') + newHTML + (postHtml || '');
-    }
-    html = preHtml = postHtml = null; // free memory
-    if (newHTML !== curHTML)
-    {
-      curHTML = newHTML;
-      result.node.innerHTML = curHTML;
-    }
-    if (lineClass !== null) result.node.className = lineClass;
-  }
-  result.prepareForAdd = writeHTML;
-  result.finishUpdate = writeHTML;
-  result.getInnerHTML = function()
-  {
-    return curHTML || '';
-  };
-
-  return result;
-};
-
-domline.escapeHTML = function(s)
-{
-  var re = /[&<>'"]/g;
-  /']/; // stupid indentation thing
-  if (!re.MAP)
-  {
-    // persisted across function calls!
-    re.MAP = {
-      '&': '&amp;',
-      '<': '&lt;',
-      '>': '&gt;',
-      '"': '&#34;',
-      "'": '&#39;'
-    };
-  }
-  return s.replace(re, function(c)
-  {
-    return re.MAP[c];
-  });
-};
-
-domline.processSpaces = function(s, doesWrap)
-{
-  if (s.indexOf("<") < 0 && !doesWrap)
-  {
-    // short-cut
-    return s.replace(/ /g, '&nbsp;');
-  }
-  var parts = [];
-  s.replace(/<[^>]*>?| |[^ <]+/g, function(m)
-  {
-    parts.push(m);
-  });
-  if (doesWrap)
-  {
-    var endOfLine = true;
-    var beforeSpace = false;
-    // last space in a run is normal, others are nbsp,
-    // end of line is nbsp
-    for (var i = parts.length - 1; i >= 0; i--)
-    {
-      var p = parts[i];
-      if (p == " ")
-      {
-        if (endOfLine || beforeSpace) parts[i] = '&nbsp;';
-        endOfLine = false;
-        beforeSpace = true;
-      }
-      else if (p.charAt(0) != "<")
-      {
-        endOfLine = false;
-        beforeSpace = false;
-      }
-    }
-    // beginning of line is nbsp
-    for (var i = 0; i < parts.length; i++)
-    {
-      var p = parts[i];
-      if (p == " ")
-      {
-        parts[i] = '&nbsp;';
-        break;
-      }
-      else if (p.charAt(0) != "<")
-      {
-        break;
-      }
-    }
-  }
-  else
-  {
-    for (var i = 0; i < parts.length; i++)
-    {
-      var p = parts[i];
-      if (p == " ")
-      {
-        parts[i] = '&nbsp;';
-      }
-    }
-  }
-  return parts.join('');
-};
-
-exports.domline = domline;
diff --git a/static/js/easysync2_client.js b/static/js/easysync2_client.js
deleted file mode 100644
index f4f3d08f..00000000
--- a/static/js/easysync2_client.js
+++ /dev/null
@@ -1,2274 +0,0 @@
-/**
- * This code is mostly from the old Etherpad. Please help us to comment this code. 
- * This helps other people to understand this code better and helps them to improve it.
- * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
- */
-
-// DO NOT EDIT THIS FILE, edit infrastructure/ace/www/easysync2.js
-// THIS FILE IS ALSO AN APPJET MODULE: etherpad.collab.ace.easysync2
-/**
- * Copyright 2009 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS-IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-//var _opt = (this.Easysync2Support || null);
-var _opt = null; // disable optimization for now
-
-function AttribPool()
-{
-  var p = {};
-  p.numToAttrib = {}; // e.g. {0: ['foo','bar']}
-  p.attribToNum = {}; // e.g. {'foo,bar': 0}
-  p.nextNum = 0;
-
-  p.putAttrib = function(attrib, dontAddIfAbsent)
-  {
-    var str = String(attrib);
-    if (str in p.attribToNum)
-    {
-      return p.attribToNum[str];
-    }
-    if (dontAddIfAbsent)
-    {
-      return -1;
-    }
-    var num = p.nextNum++;
-    p.attribToNum[str] = num;
-    p.numToAttrib[num] = [String(attrib[0] || ''), String(attrib[1] || '')];
-    return num;
-  };
-
-  p.getAttrib = function(num)
-  {
-    var pair = p.numToAttrib[num];
-    if (!pair) return pair;
-    return [pair[0], pair[1]]; // return a mutable copy
-  };
-
-  p.getAttribKey = function(num)
-  {
-    var pair = p.numToAttrib[num];
-    if (!pair) return '';
-    return pair[0];
-  };
-
-  p.getAttribValue = function(num)
-  {
-    var pair = p.numToAttrib[num];
-    if (!pair) return '';
-    return pair[1];
-  };
-
-  p.eachAttrib = function(func)
-  {
-    for (var n in p.numToAttrib)
-    {
-      var pair = p.numToAttrib[n];
-      func(pair[0], pair[1]);
-    }
-  };
-
-  p.toJsonable = function()
-  {
-    return {
-      numToAttrib: p.numToAttrib,
-      nextNum: p.nextNum
-    };
-  };
-
-  p.fromJsonable = function(obj)
-  {
-    p.numToAttrib = obj.numToAttrib;
-    p.nextNum = obj.nextNum;
-    p.attribToNum = {};
-    for (var n in p.numToAttrib)
-    {
-      p.attribToNum[String(p.numToAttrib[n])] = Number(n);
-    }
-    return p;
-  };
-
-  return p;
-}
-
-var Changeset = {};
-
-Changeset.error = function error(msg)
-{
-  var e = new Error(msg);
-  e.easysync = true;
-  throw e;
-};
-Changeset.assert = function assert(b, msgParts)
-{
-  if (!b)
-  {
-    var msg = Array.prototype.slice.call(arguments, 1).join('');
-    Changeset.error("Changeset: " + msg);
-  }
-};
-
-Changeset.parseNum = function(str)
-{
-  return parseInt(str, 36);
-};
-Changeset.numToString = function(num)
-{
-  return num.toString(36).toLowerCase();
-};
-Changeset.toBaseTen = function(cs)
-{
-  var dollarIndex = cs.indexOf('$');
-  var beforeDollar = cs.substring(0, dollarIndex);
-  var fromDollar = cs.substring(dollarIndex);
-  return beforeDollar.replace(/[0-9a-z]+/g, function(s)
-  {
-    return String(Changeset.parseNum(s));
-  }) + fromDollar;
-};
-
-Changeset.oldLen = function(cs)
-{
-  return Changeset.unpack(cs).oldLen;
-};
-Changeset.newLen = function(cs)
-{
-  return Changeset.unpack(cs).newLen;
-};
-
-Changeset.opIterator = function(opsStr, optStartIndex)
-{
-  //print(opsStr);
-  var regex = /((?:\*[0-9a-z]+)*)(?:\|([0-9a-z]+))?([-+=])([0-9a-z]+)|\?|/g;
-  var startIndex = (optStartIndex || 0);
-  var curIndex = startIndex;
-  var prevIndex = curIndex;
-
-  function nextRegexMatch()
-  {
-    prevIndex = curIndex;
-    var result;
-    if (_opt)
-    {
-      result = _opt.nextOpInString(opsStr, curIndex);
-      if (result)
-      {
-        if (result.opcode() == '?')
-        {
-          Changeset.error("Hit error opcode in op stream");
-        }
-        curIndex = result.lastIndex();
-      }
-    }
-    else
-    {
-      regex.lastIndex = curIndex;
-      result = regex.exec(opsStr);
-      curIndex = regex.lastIndex;
-      if (result[0] == '?')
-      {
-        Changeset.error("Hit error opcode in op stream");
-      }
-    }
-    return result;
-  }
-  var regexResult = nextRegexMatch();
-  var obj = Changeset.newOp();
-
-  function next(optObj)
-  {
-    var op = (optObj || obj);
-    if (_opt && regexResult)
-    {
-      op.attribs = regexResult.attribs();
-      op.lines = regexResult.lines();
-      op.chars = regexResult.chars();
-      op.opcode = regexResult.opcode();
-      regexResult = nextRegexMatch();
-    }
-    else if ((!_opt) && regexResult[0])
-    {
-      op.attribs = regexResult[1];
-      op.lines = Changeset.parseNum(regexResult[2] || 0);
-      op.opcode = regexResult[3];
-      op.chars = Changeset.parseNum(regexResult[4]);
-      regexResult = nextRegexMatch();
-    }
-    else
-    {
-      Changeset.clearOp(op);
-    }
-    return op;
-  }
-
-  function hasNext()
-  {
-    return !!(_opt ? regexResult : regexResult[0]);
-  }
-
-  function lastIndex()
-  {
-    return prevIndex;
-  }
-  return {
-    next: next,
-    hasNext: hasNext,
-    lastIndex: lastIndex
-  };
-};
-
-Changeset.clearOp = function(op)
-{
-  op.opcode = '';
-  op.chars = 0;
-  op.lines = 0;
-  op.attribs = '';
-};
-Changeset.newOp = function(optOpcode)
-{
-  return {
-    opcode: (optOpcode || ''),
-    chars: 0,
-    lines: 0,
-    attribs: ''
-  };
-};
-Changeset.cloneOp = function(op)
-{
-  return {
-    opcode: op.opcode,
-    chars: op.chars,
-    lines: op.lines,
-    attribs: op.attribs
-  };
-};
-Changeset.copyOp = function(op1, op2)
-{
-  op2.opcode = op1.opcode;
-  op2.chars = op1.chars;
-  op2.lines = op1.lines;
-  op2.attribs = op1.attribs;
-};
-Changeset.opString = function(op)
-{
-  // just for debugging
-  if (!op.opcode) return 'null';
-  var assem = Changeset.opAssembler();
-  assem.append(op);
-  return assem.toString();
-};
-Changeset.stringOp = function(str)
-{
-  // just for debugging
-  return Changeset.opIterator(str).next();
-};
-
-Changeset.checkRep = function(cs)
-{
-  // doesn't check things that require access to attrib pool (e.g. attribute order)
-  // or original string (e.g. newline positions)
-  var unpacked = Changeset.unpack(cs);
-  var oldLen = unpacked.oldLen;
-  var newLen = unpacked.newLen;
-  var ops = unpacked.ops;
-  var charBank = unpacked.charBank;
-
-  var assem = Changeset.smartOpAssembler();
-  var oldPos = 0;
-  var calcNewLen = 0;
-  var numInserted = 0;
-  var iter = Changeset.opIterator(ops);
-  while (iter.hasNext())
-  {
-    var o = iter.next();
-    switch (o.opcode)
-    {
-    case '=':
-      oldPos += o.chars;
-      calcNewLen += o.chars;
-      break;
-    case '-':
-      oldPos += o.chars;
-      Changeset.assert(oldPos < oldLen, oldPos, " >= ", oldLen, " in ", cs);
-      break;
-    case '+':
-      {
-        calcNewLen += o.chars;
-        numInserted += o.chars;
-        Changeset.assert(calcNewLen < newLen, calcNewLen, " >= ", newLen, " in ", cs);
-        break;
-      }
-    }
-    assem.append(o);
-  }
-
-  calcNewLen += oldLen - oldPos;
-  charBank = charBank.substring(0, numInserted);
-  while (charBank.length < numInserted)
-  {
-    charBank += "?";
-  }
-
-  assem.endDocument();
-  var normalized = Changeset.pack(oldLen, calcNewLen, assem.toString(), charBank);
-  Changeset.assert(normalized == cs, normalized, ' != ', cs);
-
-  return cs;
-}
-
-Changeset.smartOpAssembler = function()
-{
-  // Like opAssembler but able to produce conforming changesets
-  // from slightly looser input, at the cost of speed.
-  // Specifically:
-  // - merges consecutive operations that can be merged
-  // - strips final "="
-  // - ignores 0-length changes
-  // - reorders consecutive + and - (which margingOpAssembler doesn't do)
-  var minusAssem = Changeset.mergingOpAssembler();
-  var plusAssem = Changeset.mergingOpAssembler();
-  var keepAssem = Changeset.mergingOpAssembler();
-  var assem = Changeset.stringAssembler();
-  var lastOpcode = '';
-  var lengthChange = 0;
-
-  function flushKeeps()
-  {
-    assem.append(keepAssem.toString());
-    keepAssem.clear();
-  }
-
-  function flushPlusMinus()
-  {
-    assem.append(minusAssem.toString());
-    minusAssem.clear();
-    assem.append(plusAssem.toString());
-    plusAssem.clear();
-  }
-
-  function append(op)
-  {
-    if (!op.opcode) return;
-    if (!op.chars) return;
-
-    if (op.opcode == '-')
-    {
-      if (lastOpcode == '=')
-      {
-        flushKeeps();
-      }
-      minusAssem.append(op);
-      lengthChange -= op.chars;
-    }
-    else if (op.opcode == '+')
-    {
-      if (lastOpcode == '=')
-      {
-        flushKeeps();
-      }
-      plusAssem.append(op);
-      lengthChange += op.chars;
-    }
-    else if (op.opcode == '=')
-    {
-      if (lastOpcode != '=')
-      {
-        flushPlusMinus();
-      }
-      keepAssem.append(op);
-    }
-    lastOpcode = op.opcode;
-  }
-
-  function appendOpWithText(opcode, text, attribs, pool)
-  {
-    var op = Changeset.newOp(opcode);
-    op.attribs = Changeset.makeAttribsString(opcode, attribs, pool);
-    var lastNewlinePos = text.lastIndexOf('\n');
-    if (lastNewlinePos < 0)
-    {
-      op.chars = text.length;
-      op.lines = 0;
-      append(op);
-    }
-    else
-    {
-      op.chars = lastNewlinePos + 1;
-      op.lines = text.match(/\n/g).length;
-      append(op);
-      op.chars = text.length - (lastNewlinePos + 1);
-      op.lines = 0;
-      append(op);
-    }
-  }
-
-  function toString()
-  {
-    flushPlusMinus();
-    flushKeeps();
-    return assem.toString();
-  }
-
-  function clear()
-  {
-    minusAssem.clear();
-    plusAssem.clear();
-    keepAssem.clear();
-    assem.clear();
-    lengthChange = 0;
-  }
-
-  function endDocument()
-  {
-    keepAssem.endDocument();
-  }
-
-  function getLengthChange()
-  {
-    return lengthChange;
-  }
-
-  return {
-    append: append,
-    toString: toString,
-    clear: clear,
-    endDocument: endDocument,
-    appendOpWithText: appendOpWithText,
-    getLengthChange: getLengthChange
-  };
-};
-
-if (_opt)
-{
-  Changeset.mergingOpAssembler = function()
-  {
-    var assem = _opt.mergingOpAssembler();
-
-    function append(op)
-    {
-      assem.append(op.opcode, op.chars, op.lines, op.attribs);
-    }
-
-    function toString()
-    {
-      return assem.toString();
-    }
-
-    function clear()
-    {
-      assem.clear();
-    }
-
-    function endDocument()
-    {
-      assem.endDocument();
-    }
-
-    return {
-      append: append,
-      toString: toString,
-      clear: clear,
-      endDocument: endDocument
-    };
-  };
-}
-else
-{
-  Changeset.mergingOpAssembler = function()
-  {
-    // This assembler can be used in production; it efficiently
-    // merges consecutive operations that are mergeable, ignores
-    // no-ops, and drops final pure "keeps".  It does not re-order
-    // operations.
-    var assem = Changeset.opAssembler();
-    var bufOp = Changeset.newOp();
-
-    // If we get, for example, insertions [xxx\n,yyy], those don't merge,
-    // but if we get [xxx\n,yyy,zzz\n], that merges to [xxx\nyyyzzz\n].
-    // This variable stores the length of yyy and any other newline-less
-    // ops immediately after it.
-    var bufOpAdditionalCharsAfterNewline = 0;
-
-    function flush(isEndDocument)
-    {
-      if (bufOp.opcode)
-      {
-        if (isEndDocument && bufOp.opcode == '=' && !bufOp.attribs)
-        {
-          // final merged keep, leave it implicit
-        }
-        else
-        {
-          assem.append(bufOp);
-          if (bufOpAdditionalCharsAfterNewline)
-          {
-            bufOp.chars = bufOpAdditionalCharsAfterNewline;
-            bufOp.lines = 0;
-            assem.append(bufOp);
-            bufOpAdditionalCharsAfterNewline = 0;
-          }
-        }
-        bufOp.opcode = '';
-      }
-    }
-
-    function append(op)
-    {
-      if (op.chars > 0)
-      {
-        if (bufOp.opcode == op.opcode && bufOp.attribs == op.attribs)
-        {
-          if (op.lines > 0)
-          {
-            // bufOp and additional chars are all mergeable into a multi-line op
-            bufOp.chars += bufOpAdditionalCharsAfterNewline + op.chars;
-            bufOp.lines += op.lines;
-            bufOpAdditionalCharsAfterNewline = 0;
-          }
-          else if (bufOp.lines == 0)
-          {
-            // both bufOp and op are in-line
-            bufOp.chars += op.chars;
-          }
-          else
-          {
-            // append in-line text to multi-line bufOp
-            bufOpAdditionalCharsAfterNewline += op.chars;
-          }
-        }
-        else
-        {
-          flush();
-          Changeset.copyOp(op, bufOp);
-        }
-      }
-    }
-
-    function endDocument()
-    {
-      flush(true);
-    }
-
-    function toString()
-    {
-      flush();
-      return assem.toString();
-    }
-
-    function clear()
-    {
-      assem.clear();
-      Changeset.clearOp(bufOp);
-    }
-    return {
-      append: append,
-      toString: toString,
-      clear: clear,
-      endDocument: endDocument
-    };
-  };
-}
-
-if (_opt)
-{
-  Changeset.opAssembler = function()
-  {
-    var assem = _opt.opAssembler();
-    // this function allows op to be mutated later (doesn't keep a ref)
-
-    function append(op)
-    {
-      assem.append(op.opcode, op.chars, op.lines, op.attribs);
-    }
-
-    function toString()
-    {
-      return assem.toString();
-    }
-
-    function clear()
-    {
-      assem.clear();
-    }
-    return {
-      append: append,
-      toString: toString,
-      clear: clear
-    };
-  };
-}
-else
-{
-  Changeset.opAssembler = function()
-  {
-    var pieces = [];
-    // this function allows op to be mutated later (doesn't keep a ref)
-
-    function append(op)
-    {
-      pieces.push(op.attribs);
-      if (op.lines)
-      {
-        pieces.push('|', Changeset.numToString(op.lines));
-      }
-      pieces.push(op.opcode);
-      pieces.push(Changeset.numToString(op.chars));
-    }
-
-    function toString()
-    {
-      return pieces.join('');
-    }
-
-    function clear()
-    {
-      pieces.length = 0;
-    }
-    return {
-      append: append,
-      toString: toString,
-      clear: clear
-    };
-  };
-}
-
-Changeset.stringIterator = function(str)
-{
-  var curIndex = 0;
-
-  function assertRemaining(n)
-  {
-    Changeset.assert(n <= remaining(), "!(", n, " <= ", remaining(), ")");
-  }
-
-  function take(n)
-  {
-    assertRemaining(n);
-    var s = str.substr(curIndex, n);
-    curIndex += n;
-    return s;
-  }
-
-  function peek(n)
-  {
-    assertRemaining(n);
-    var s = str.substr(curIndex, n);
-    return s;
-  }
-
-  function skip(n)
-  {
-    assertRemaining(n);
-    curIndex += n;
-  }
-
-  function remaining()
-  {
-    return str.length - curIndex;
-  }
-  return {
-    take: take,
-    skip: skip,
-    remaining: remaining,
-    peek: peek
-  };
-};
-
-Changeset.stringAssembler = function()
-{
-  var pieces = [];
-
-  function append(x)
-  {
-    pieces.push(String(x));
-  }
-
-  function toString()
-  {
-    return pieces.join('');
-  }
-  return {
-    append: append,
-    toString: toString
-  };
-};
-
-// "lines" need not be an array as long as it supports certain calls (lines_foo inside).
-Changeset.textLinesMutator = function(lines)
-{
-  // Mutates lines, an array of strings, in place.
-  // Mutation operations have the same constraints as changeset operations
-  // with respect to newlines, but not the other additional constraints
-  // (i.e. ins/del ordering, forbidden no-ops, non-mergeability, final newline).
-  // Can be used to mutate lists of strings where the last char of each string
-  // is not actually a newline, but for the purposes of N and L values,
-  // the caller should pretend it is, and for things to work right in that case, the input
-  // to insert() should be a single line with no newlines.
-  var curSplice = [0, 0];
-  var inSplice = false;
-  // position in document after curSplice is applied:
-  var curLine = 0,
-      curCol = 0;
-  // invariant: if (inSplice) then (curLine is in curSplice[0] + curSplice.length - {2,3}) &&
-  //            curLine >= curSplice[0]
-  // invariant: if (inSplice && (curLine >= curSplice[0] + curSplice.length - 2)) then
-  //            curCol == 0
-
-  function lines_applySplice(s)
-  {
-    lines.splice.apply(lines, s);
-  }
-
-  function lines_toSource()
-  {
-    return lines.toSource();
-  }
-
-  function lines_get(idx)
-  {
-    if (lines.get)
-    {
-      return lines.get(idx);
-    }
-    else
-    {
-      return lines[idx];
-    }
-  }
-  // can be unimplemented if removeLines's return value not needed
-
-  function lines_slice(start, end)
-  {
-    if (lines.slice)
-    {
-      return lines.slice(start, end);
-    }
-    else
-    {
-      return [];
-    }
-  }
-
-  function lines_length()
-  {
-    if ((typeof lines.length) == "number")
-    {
-      return lines.length;
-    }
-    else
-    {
-      return lines.length();
-    }
-  }
-
-  function enterSplice()
-  {
-    curSplice[0] = curLine;
-    curSplice[1] = 0;
-    if (curCol > 0)
-    {
-      putCurLineInSplice();
-    }
-    inSplice = true;
-  }
-
-  function leaveSplice()
-  {
-    lines_applySplice(curSplice);
-    curSplice.length = 2;
-    curSplice[0] = curSplice[1] = 0;
-    inSplice = false;
-  }
-
-  function isCurLineInSplice()
-  {
-    return (curLine - curSplice[0] < (curSplice.length - 2));
-  }
-
-  function debugPrint(typ)
-  {
-    print(typ + ": " + curSplice.toSource() + " / " + curLine + "," + curCol + " / " + lines_toSource());
-  }
-
-  function putCurLineInSplice()
-  {
-    if (!isCurLineInSplice())
-    {
-      curSplice.push(lines_get(curSplice[0] + curSplice[1]));
-      curSplice[1]++;
-    }
-    return 2 + curLine - curSplice[0];
-  }
-
-  function skipLines(L, includeInSplice)
-  {
-    if (L)
-    {
-      if (includeInSplice)
-      {
-        if (!inSplice)
-        {
-          enterSplice();
-        }
-        for (var i = 0; i < L; i++)
-        {
-          curCol = 0;
-          putCurLineInSplice();
-          curLine++;
-        }
-      }
-      else
-      {
-        if (inSplice)
-        {
-          if (L > 1)
-          {
-            leaveSplice();
-          }
-          else
-          {
-            putCurLineInSplice();
-          }
-        }
-        curLine += L;
-        curCol = 0;
-      }
-      //print(inSplice+" / "+isCurLineInSplice()+" / "+curSplice[0]+" / "+curSplice[1]+" / "+lines.length);
-/*if (inSplice && (! isCurLineInSplice()) && (curSplice[0] + curSplice[1] < lines.length)) {
-	  print("BLAH");
-	  putCurLineInSplice();
-	}*/
-      // tests case foo in remove(), which isn't otherwise covered in current impl
-    }
-    //debugPrint("skip");
-  }
-
-  function skip(N, L, includeInSplice)
-  {
-    if (N)
-    {
-      if (L)
-      {
-        skipLines(L, includeInSplice);
-      }
-      else
-      {
-        if (includeInSplice && !inSplice)
-        {
-          enterSplice();
-        }
-        if (inSplice)
-        {
-          putCurLineInSplice();
-        }
-        curCol += N;
-        //debugPrint("skip");
-      }
-    }
-  }
-
-  function removeLines(L)
-  {
-    var removed = '';
-    if (L)
-    {
-      if (!inSplice)
-      {
-        enterSplice();
-      }
-
-      function nextKLinesText(k)
-      {
-        var m = curSplice[0] + curSplice[1];
-        return lines_slice(m, m + k).join('');
-      }
-      if (isCurLineInSplice())
-      {
-        //print(curCol);
-        if (curCol == 0)
-        {
-          removed = curSplice[curSplice.length - 1];
-          // print("FOO"); // case foo
-          curSplice.length--;
-          removed += nextKLinesText(L - 1);
-          curSplice[1] += L - 1;
-        }
-        else
-        {
-          removed = nextKLinesText(L - 1);
-          curSplice[1] += L - 1;
-          var sline = curSplice.length - 1;
-          removed = curSplice[sline].substring(curCol) + removed;
-          curSplice[sline] = curSplice[sline].substring(0, curCol) + lines_get(curSplice[0] + curSplice[1]);
-          curSplice[1] += 1;
-        }
-      }
-      else
-      {
-        removed = nextKLinesText(L);
-        curSplice[1] += L;
-      }
-      //debugPrint("remove");
-    }
-    return removed;
-  }
-
-  function remove(N, L)
-  {
-    var removed = '';
-    if (N)
-    {
-      if (L)
-      {
-        return removeLines(L);
-      }
-      else
-      {
-        if (!inSplice)
-        {
-          enterSplice();
-        }
-        var sline = putCurLineInSplice();
-        removed = curSplice[sline].substring(curCol, curCol + N);
-        curSplice[sline] = curSplice[sline].substring(0, curCol) + curSplice[sline].substring(curCol + N);
-        //debugPrint("remove");
-      }
-    }
-    return removed;
-  }
-
-  function insert(text, L)
-  {
-    if (text)
-    {
-      if (!inSplice)
-      {
-        enterSplice();
-      }
-      if (L)
-      {
-        var newLines = Changeset.splitTextLines(text);
-        if (isCurLineInSplice())
-        {
-          //if (curCol == 0) {
-          //curSplice.length--;
-          //curSplice[1]--;
-          //Array.prototype.push.apply(curSplice, newLines);
-          //curLine += newLines.length;
-          //}
-          //else {
-          var sline = curSplice.length - 1;
-          var theLine = curSplice[sline];
-          var lineCol = curCol;
-          curSplice[sline] = theLine.substring(0, lineCol) + newLines[0];
-          curLine++;
-          newLines.splice(0, 1);
-          Array.prototype.push.apply(curSplice, newLines);
-          curLine += newLines.length;
-          curSplice.push(theLine.substring(lineCol));
-          curCol = 0;
-          //}
-        }
-        else
-        {
-          Array.prototype.push.apply(curSplice, newLines);
-          curLine += newLines.length;
-        }
-      }
-      else
-      {
-        var sline = putCurLineInSplice();
-        curSplice[sline] = curSplice[sline].substring(0, curCol) + text + curSplice[sline].substring(curCol);
-        curCol += text.length;
-      }
-      //debugPrint("insert");
-    }
-  }
-
-  function hasMore()
-  {
-    //print(lines.length+" / "+inSplice+" / "+(curSplice.length - 2)+" / "+curSplice[1]);
-    var docLines = lines_length();
-    if (inSplice)
-    {
-      docLines += curSplice.length - 2 - curSplice[1];
-    }
-    return curLine < docLines;
-  }
-
-  function close()
-  {
-    if (inSplice)
-    {
-      leaveSplice();
-    }
-    //debugPrint("close");
-  }
-
-  var self = {
-    skip: skip,
-    remove: remove,
-    insert: insert,
-    close: close,
-    hasMore: hasMore,
-    removeLines: removeLines,
-    skipLines: skipLines
-  };
-  return self;
-};
-
-Changeset.applyZip = function(in1, idx1, in2, idx2, func)
-{
-  var iter1 = Changeset.opIterator(in1, idx1);
-  var iter2 = Changeset.opIterator(in2, idx2);
-  var assem = Changeset.smartOpAssembler();
-  var op1 = Changeset.newOp();
-  var op2 = Changeset.newOp();
-  var opOut = Changeset.newOp();
-  while (op1.opcode || iter1.hasNext() || op2.opcode || iter2.hasNext())
-  {
-    if ((!op1.opcode) && iter1.hasNext()) iter1.next(op1);
-    if ((!op2.opcode) && iter2.hasNext()) iter2.next(op2);
-    func(op1, op2, opOut);
-    if (opOut.opcode)
-    {
-      //print(opOut.toSource());
-      assem.append(opOut);
-      opOut.opcode = '';
-    }
-  }
-  assem.endDocument();
-  return assem.toString();
-};
-
-Changeset.unpack = function(cs)
-{
-  var headerRegex = /Z:([0-9a-z]+)([><])([0-9a-z]+)|/;
-  var headerMatch = headerRegex.exec(cs);
-  if ((!headerMatch) || (!headerMatch[0]))
-  {
-    Changeset.error("Not a changeset: " + cs);
-  }
-  var oldLen = Changeset.parseNum(headerMatch[1]);
-  var changeSign = (headerMatch[2] == '>') ? 1 : -1;
-  var changeMag = Changeset.parseNum(headerMatch[3]);
-  var newLen = oldLen + changeSign * changeMag;
-  var opsStart = headerMatch[0].length;
-  var opsEnd = cs.indexOf("$");
-  if (opsEnd < 0) opsEnd = cs.length;
-  return {
-    oldLen: oldLen,
-    newLen: newLen,
-    ops: cs.substring(opsStart, opsEnd),
-    charBank: cs.substring(opsEnd + 1)
-  };
-};
-
-Changeset.pack = function(oldLen, newLen, opsStr, bank)
-{
-  var lenDiff = newLen - oldLen;
-  var lenDiffStr = (lenDiff >= 0 ? '>' + Changeset.numToString(lenDiff) : '<' + Changeset.numToString(-lenDiff));
-  var a = [];
-  a.push('Z:', Changeset.numToString(oldLen), lenDiffStr, opsStr, '$', bank);
-  return a.join('');
-};
-
-Changeset.applyToText = function(cs, str)
-{
-  var unpacked = Changeset.unpack(cs);
-  Changeset.assert(str.length == unpacked.oldLen, "mismatched apply: ", str.length, " / ", unpacked.oldLen);
-  var csIter = Changeset.opIterator(unpacked.ops);
-  var bankIter = Changeset.stringIterator(unpacked.charBank);
-  var strIter = Changeset.stringIterator(str);
-  var assem = Changeset.stringAssembler();
-  while (csIter.hasNext())
-  {
-    var op = csIter.next();
-    switch (op.opcode)
-    {
-    case '+':
-      assem.append(bankIter.take(op.chars));
-      break;
-    case '-':
-      strIter.skip(op.chars);
-      break;
-    case '=':
-      assem.append(strIter.take(op.chars));
-      break;
-    }
-  }
-  assem.append(strIter.take(strIter.remaining()));
-  return assem.toString();
-};
-
-Changeset.mutateTextLines = function(cs, lines)
-{
-  var unpacked = Changeset.unpack(cs);
-  var csIter = Changeset.opIterator(unpacked.ops);
-  var bankIter = Changeset.stringIterator(unpacked.charBank);
-  var mut = Changeset.textLinesMutator(lines);
-  while (csIter.hasNext())
-  {
-    var op = csIter.next();
-    switch (op.opcode)
-    {
-    case '+':
-      mut.insert(bankIter.take(op.chars), op.lines);
-      break;
-    case '-':
-      mut.remove(op.chars, op.lines);
-      break;
-    case '=':
-      mut.skip(op.chars, op.lines, ( !! op.attribs));
-      break;
-    }
-  }
-  mut.close();
-};
-
-Changeset.composeAttributes = function(att1, att2, resultIsMutation, pool)
-{
-  // att1 and att2 are strings like "*3*f*1c", asMutation is a boolean.
-  // Sometimes attribute (key,value) pairs are treated as attribute presence
-  // information, while other times they are treated as operations that
-  // mutate a set of attributes, and this affects whether an empty value
-  // is a deletion or a change.
-  // Examples, of the form (att1Items, att2Items, resultIsMutation) -> result
-  // ([], [(bold, )], true) -> [(bold, )]
-  // ([], [(bold, )], false) -> []
-  // ([], [(bold, true)], true) -> [(bold, true)]
-  // ([], [(bold, true)], false) -> [(bold, true)]
-  // ([(bold, true)], [(bold, )], true) -> [(bold, )]
-  // ([(bold, true)], [(bold, )], false) -> []
-  // pool can be null if att2 has no attributes.
-  if ((!att1) && resultIsMutation)
-  {
-    // In the case of a mutation (i.e. composing two changesets),
-    // an att2 composed with an empy att1 is just att2.  If att1
-    // is part of an attribution string, then att2 may remove
-    // attributes that are already gone, so don't do this optimization.
-    return att2;
-  }
-  if (!att2) return att1;
-  var atts = [];
-  att1.replace(/\*([0-9a-z]+)/g, function(_, a)
-  {
-    atts.push(pool.getAttrib(Changeset.parseNum(a)));
-    return '';
-  });
-  att2.replace(/\*([0-9a-z]+)/g, function(_, a)
-  {
-    var pair = pool.getAttrib(Changeset.parseNum(a));
-    var found = false;
-    for (var i = 0; i < atts.length; i++)
-    {
-      var oldPair = atts[i];
-      if (oldPair[0] == pair[0])
-      {
-        if (pair[1] || resultIsMutation)
-        {
-          oldPair[1] = pair[1];
-        }
-        else
-        {
-          atts.splice(i, 1);
-        }
-        found = true;
-        break;
-      }
-    }
-    if ((!found) && (pair[1] || resultIsMutation))
-    {
-      atts.push(pair);
-    }
-    return '';
-  });
-  atts.sort();
-  var buf = Changeset.stringAssembler();
-  for (var i = 0; i < atts.length; i++)
-  {
-    buf.append('*');
-    buf.append(Changeset.numToString(pool.putAttrib(atts[i])));
-  }
-  //print(att1+" / "+att2+" / "+buf.toString());
-  return buf.toString();
-};
-
-Changeset._slicerZipperFunc = function(attOp, csOp, opOut, pool)
-{
-  // attOp is the op from the sequence that is being operated on, either an
-  // attribution string or the earlier of two changesets being composed.
-  // pool can be null if definitely not needed.
-  //print(csOp.toSource()+" "+attOp.toSource()+" "+opOut.toSource());
-  if (attOp.opcode == '-')
-  {
-    Changeset.copyOp(attOp, opOut);
-    attOp.opcode = '';
-  }
-  else if (!attOp.opcode)
-  {
-    Changeset.copyOp(csOp, opOut);
-    csOp.opcode = '';
-  }
-  else
-  {
-    switch (csOp.opcode)
-    {
-    case '-':
-      {
-        if (csOp.chars <= attOp.chars)
-        {
-          // delete or delete part
-          if (attOp.opcode == '=')
-          {
-            opOut.opcode = '-';
-            opOut.chars = csOp.chars;
-            opOut.lines = csOp.lines;
-            opOut.attribs = '';
-          }
-          attOp.chars -= csOp.chars;
-          attOp.lines -= csOp.lines;
-          csOp.opcode = '';
-          if (!attOp.chars)
-          {
-            attOp.opcode = '';
-          }
-        }
-        else
-        {
-          // delete and keep going
-          if (attOp.opcode == '=')
-          {
-            opOut.opcode = '-';
-            opOut.chars = attOp.chars;
-            opOut.lines = attOp.lines;
-            opOut.attribs = '';
-          }
-          csOp.chars -= attOp.chars;
-          csOp.lines -= attOp.lines;
-          attOp.opcode = '';
-        }
-        break;
-      }
-    case '+':
-      {
-        // insert
-        Changeset.copyOp(csOp, opOut);
-        csOp.opcode = '';
-        break;
-      }
-    case '=':
-      {
-        if (csOp.chars <= attOp.chars)
-        {
-          // keep or keep part
-          opOut.opcode = attOp.opcode;
-          opOut.chars = csOp.chars;
-          opOut.lines = csOp.lines;
-          opOut.attribs = Changeset.composeAttributes(attOp.attribs, csOp.attribs, attOp.opcode == '=', pool);
-          csOp.opcode = '';
-          attOp.chars -= csOp.chars;
-          attOp.lines -= csOp.lines;
-          if (!attOp.chars)
-          {
-            attOp.opcode = '';
-          }
-        }
-        else
-        {
-          // keep and keep going
-          opOut.opcode = attOp.opcode;
-          opOut.chars = attOp.chars;
-          opOut.lines = attOp.lines;
-          opOut.attribs = Changeset.composeAttributes(attOp.attribs, csOp.attribs, attOp.opcode == '=', pool);
-          attOp.opcode = '';
-          csOp.chars -= attOp.chars;
-          csOp.lines -= attOp.lines;
-        }
-        break;
-      }
-    case '':
-      {
-        Changeset.copyOp(attOp, opOut);
-        attOp.opcode = '';
-        break;
-      }
-    }
-  }
-};
-
-Changeset.applyToAttribution = function(cs, astr, pool)
-{
-  var unpacked = Changeset.unpack(cs);
-
-  return Changeset.applyZip(astr, 0, unpacked.ops, 0, function(op1, op2, opOut)
-  {
-    return Changeset._slicerZipperFunc(op1, op2, opOut, pool);
-  });
-};
-
-/*Changeset.oneInsertedLineAtATimeOpIterator = function(opsStr, optStartIndex, charBank) {
-  var iter = Changeset.opIterator(opsStr, optStartIndex);
-  var bankIndex = 0;
-
-};*/
-
-Changeset.mutateAttributionLines = function(cs, lines, pool)
-{
-  //dmesg(cs);
-  //dmesg(lines.toSource()+" ->");
-  var unpacked = Changeset.unpack(cs);
-  var csIter = Changeset.opIterator(unpacked.ops);
-  var csBank = unpacked.charBank;
-  var csBankIndex = 0;
-  // treat the attribution lines as text lines, mutating a line at a time
-  var mut = Changeset.textLinesMutator(lines);
-
-  var lineIter = null;
-
-  function isNextMutOp()
-  {
-    return (lineIter && lineIter.hasNext()) || mut.hasMore();
-  }
-
-  function nextMutOp(destOp)
-  {
-    if ((!(lineIter && lineIter.hasNext())) && mut.hasMore())
-    {
-      var line = mut.removeLines(1);
-      lineIter = Changeset.opIterator(line);
-    }
-    if (lineIter && lineIter.hasNext())
-    {
-      lineIter.next(destOp);
-    }
-    else
-    {
-      destOp.opcode = '';
-    }
-  }
-  var lineAssem = null;
-
-  function outputMutOp(op)
-  {
-    //print("outputMutOp: "+op.toSource());
-    if (!lineAssem)
-    {
-      lineAssem = Changeset.mergingOpAssembler();
-    }
-    lineAssem.append(op);
-    if (op.lines > 0)
-    {
-      Changeset.assert(op.lines == 1, "Can't have op.lines of ", op.lines, " in attribution lines");
-      // ship it to the mut
-      mut.insert(lineAssem.toString(), 1);
-      lineAssem = null;
-    }
-  }
-
-  var csOp = Changeset.newOp();
-  var attOp = Changeset.newOp();
-  var opOut = Changeset.newOp();
-  while (csOp.opcode || csIter.hasNext() || attOp.opcode || isNextMutOp())
-  {
-    if ((!csOp.opcode) && csIter.hasNext())
-    {
-      csIter.next(csOp);
-    }
-    //print(csOp.toSource()+" "+attOp.toSource()+" "+opOut.toSource());
-    //print(csOp.opcode+"/"+csOp.lines+"/"+csOp.attribs+"/"+lineAssem+"/"+lineIter+"/"+(lineIter?lineIter.hasNext():null));
-    //print("csOp: "+csOp.toSource());
-    if ((!csOp.opcode) && (!attOp.opcode) && (!lineAssem) && (!(lineIter && lineIter.hasNext())))
-    {
-      break; // done
-    }
-    else if (csOp.opcode == '=' && csOp.lines > 0 && (!csOp.attribs) && (!attOp.opcode) && (!lineAssem) && (!(lineIter && lineIter.hasNext())))
-    {
-      // skip multiple lines; this is what makes small changes not order of the document size
-      mut.skipLines(csOp.lines);
-      //print("skipped: "+csOp.lines);
-      csOp.opcode = '';
-    }
-    else if (csOp.opcode == '+')
-    {
-      if (csOp.lines > 1)
-      {
-        var firstLineLen = csBank.indexOf('\n', csBankIndex) + 1 - csBankIndex;
-        Changeset.copyOp(csOp, opOut);
-        csOp.chars -= firstLineLen;
-        csOp.lines--;
-        opOut.lines = 1;
-        opOut.chars = firstLineLen;
-      }
-      else
-      {
-        Changeset.copyOp(csOp, opOut);
-        csOp.opcode = '';
-      }
-      outputMutOp(opOut);
-      csBankIndex += opOut.chars;
-      opOut.opcode = '';
-    }
-    else
-    {
-      if ((!attOp.opcode) && isNextMutOp())
-      {
-        nextMutOp(attOp);
-      }
-      //print("attOp: "+attOp.toSource());
-      Changeset._slicerZipperFunc(attOp, csOp, opOut, pool);
-      if (opOut.opcode)
-      {
-        outputMutOp(opOut);
-        opOut.opcode = '';
-      }
-    }
-  }
-
-  Changeset.assert(!lineAssem, "line assembler not finished");
-  mut.close();
-
-  //dmesg("-> "+lines.toSource());
-};
-
-Changeset.joinAttributionLines = function(theAlines)
-{
-  var assem = Changeset.mergingOpAssembler();
-  for (var i = 0; i < theAlines.length; i++)
-  {
-    var aline = theAlines[i];
-    var iter = Changeset.opIterator(aline);
-    while (iter.hasNext())
-    {
-      assem.append(iter.next());
-    }
-  }
-  return assem.toString();
-};
-
-Changeset.splitAttributionLines = function(attrOps, text)
-{
-  var iter = Changeset.opIterator(attrOps);
-  var assem = Changeset.mergingOpAssembler();
-  var lines = [];
-  var pos = 0;
-
-  function appendOp(op)
-  {
-    assem.append(op);
-    if (op.lines > 0)
-    {
-      lines.push(assem.toString());
-      assem.clear();
-    }
-    pos += op.chars;
-  }
-
-  while (iter.hasNext())
-  {
-    var op = iter.next();
-    var numChars = op.chars;
-    var numLines = op.lines;
-    while (numLines > 1)
-    {
-      var newlineEnd = text.indexOf('\n', pos) + 1;
-      Changeset.assert(newlineEnd > 0, "newlineEnd <= 0 in splitAttributionLines");
-      op.chars = newlineEnd - pos;
-      op.lines = 1;
-      appendOp(op);
-      numChars -= op.chars;
-      numLines -= op.lines;
-    }
-    if (numLines == 1)
-    {
-      op.chars = numChars;
-      op.lines = 1;
-    }
-    appendOp(op);
-  }
-
-  return lines;
-};
-
-Changeset.splitTextLines = function(text)
-{
-  return text.match(/[^\n]*(?:\n|[^\n]$)/g);
-};
-
-Changeset.compose = function(cs1, cs2, pool)
-{
-  var unpacked1 = Changeset.unpack(cs1);
-  var unpacked2 = Changeset.unpack(cs2);
-  var len1 = unpacked1.oldLen;
-  var len2 = unpacked1.newLen;
-  Changeset.assert(len2 == unpacked2.oldLen, "mismatched composition");
-  var len3 = unpacked2.newLen;
-  var bankIter1 = Changeset.stringIterator(unpacked1.charBank);
-  var bankIter2 = Changeset.stringIterator(unpacked2.charBank);
-  var bankAssem = Changeset.stringAssembler();
-
-  var newOps = Changeset.applyZip(unpacked1.ops, 0, unpacked2.ops, 0, function(op1, op2, opOut)
-  {
-    //var debugBuilder = Changeset.stringAssembler();
-    //debugBuilder.append(Changeset.opString(op1));
-    //debugBuilder.append(',');
-    //debugBuilder.append(Changeset.opString(op2));
-    //debugBuilder.append(' / ');
-    var op1code = op1.opcode;
-    var op2code = op2.opcode;
-    if (op1code == '+' && op2code == '-')
-    {
-      bankIter1.skip(Math.min(op1.chars, op2.chars));
-    }
-    Changeset._slicerZipperFunc(op1, op2, opOut, pool);
-    if (opOut.opcode == '+')
-    {
-      if (op2code == '+')
-      {
-        bankAssem.append(bankIter2.take(opOut.chars));
-      }
-      else
-      {
-        bankAssem.append(bankIter1.take(opOut.chars));
-      }
-    }
-
-    //debugBuilder.append(Changeset.opString(op1));
-    //debugBuilder.append(',');
-    //debugBuilder.append(Changeset.opString(op2));
-    //debugBuilder.append(' -> ');
-    //debugBuilder.append(Changeset.opString(opOut));
-    //print(debugBuilder.toString());
-  });
-
-  return Changeset.pack(len1, len3, newOps, bankAssem.toString());
-};
-
-Changeset.attributeTester = function(attribPair, pool)
-{
-  // returns a function that tests if a string of attributes
-  // (e.g. *3*4) contains a given attribute key,value that
-  // is already present in the pool.
-  if (!pool)
-  {
-    return never;
-  }
-  var attribNum = pool.putAttrib(attribPair, true);
-  if (attribNum < 0)
-  {
-    return never;
-  }
-  else
-  {
-    var re = new RegExp('\\*' + Changeset.numToString(attribNum) + '(?!\\w)');
-    return function(attribs)
-    {
-      return re.test(attribs);
-    };
-  }
-
-  function never(attribs)
-  {
-    return false;
-  }
-};
-
-Changeset.identity = function(N)
-{
-  return Changeset.pack(N, N, "", "");
-};
-
-Changeset.makeSplice = function(oldFullText, spliceStart, numRemoved, newText, optNewTextAPairs, pool)
-{
-  var oldLen = oldFullText.length;
-
-  if (spliceStart >= oldLen)
-  {
-    spliceStart = oldLen - 1;
-  }
-  if (numRemoved > oldFullText.length - spliceStart - 1)
-  {
-    numRemoved = oldFullText.length - spliceStart - 1;
-  }
-  var oldText = oldFullText.substring(spliceStart, spliceStart + numRemoved);
-  var newLen = oldLen + newText.length - oldText.length;
-
-  var assem = Changeset.smartOpAssembler();
-  assem.appendOpWithText('=', oldFullText.substring(0, spliceStart));
-  assem.appendOpWithText('-', oldText);
-  assem.appendOpWithText('+', newText, optNewTextAPairs, pool);
-  assem.endDocument();
-  return Changeset.pack(oldLen, newLen, assem.toString(), newText);
-};
-
-Changeset.toSplices = function(cs)
-{
-  // get a list of splices, [startChar, endChar, newText]
-  var unpacked = Changeset.unpack(cs);
-  var splices = [];
-
-  var oldPos = 0;
-  var iter = Changeset.opIterator(unpacked.ops);
-  var charIter = Changeset.stringIterator(unpacked.charBank);
-  var inSplice = false;
-  while (iter.hasNext())
-  {
-    var op = iter.next();
-    if (op.opcode == '=')
-    {
-      oldPos += op.chars;
-      inSplice = false;
-    }
-    else
-    {
-      if (!inSplice)
-      {
-        splices.push([oldPos, oldPos, ""]);
-        inSplice = true;
-      }
-      if (op.opcode == '-')
-      {
-        oldPos += op.chars;
-        splices[splices.length - 1][1] += op.chars;
-      }
-      else if (op.opcode == '+')
-      {
-        splices[splices.length - 1][2] += charIter.take(op.chars);
-      }
-    }
-  }
-
-  return splices;
-};
-
-Changeset.characterRangeFollow = function(cs, startChar, endChar, insertionsAfter)
-{
-  var newStartChar = startChar;
-  var newEndChar = endChar;
-  var splices = Changeset.toSplices(cs);
-  var lengthChangeSoFar = 0;
-  for (var i = 0; i < splices.length; i++)
-  {
-    var splice = splices[i];
-    var spliceStart = splice[0] + lengthChangeSoFar;
-    var spliceEnd = splice[1] + lengthChangeSoFar;
-    var newTextLength = splice[2].length;
-    var thisLengthChange = newTextLength - (spliceEnd - spliceStart);
-
-    if (spliceStart <= newStartChar && spliceEnd >= newEndChar)
-    {
-      // splice fully replaces/deletes range
-      // (also case that handles insertion at a collapsed selection)
-      if (insertionsAfter)
-      {
-        newStartChar = newEndChar = spliceStart;
-      }
-      else
-      {
-        newStartChar = newEndChar = spliceStart + newTextLength;
-      }
-    }
-    else if (spliceEnd <= newStartChar)
-    {
-      // splice is before range
-      newStartChar += thisLengthChange;
-      newEndChar += thisLengthChange;
-    }
-    else if (spliceStart >= newEndChar)
-    {
-      // splice is after range
-    }
-    else if (spliceStart >= newStartChar && spliceEnd <= newEndChar)
-    {
-      // splice is inside range
-      newEndChar += thisLengthChange;
-    }
-    else if (spliceEnd < newEndChar)
-    {
-      // splice overlaps beginning of range
-      newStartChar = spliceStart + newTextLength;
-      newEndChar += thisLengthChange;
-    }
-    else
-    {
-      // splice overlaps end of range
-      newEndChar = spliceStart;
-    }
-
-    lengthChangeSoFar += thisLengthChange;
-  }
-
-  return [newStartChar, newEndChar];
-};
-
-Changeset.moveOpsToNewPool = function(cs, oldPool, newPool)
-{
-  // works on changeset or attribution string
-  var dollarPos = cs.indexOf('$');
-  if (dollarPos < 0)
-  {
-    dollarPos = cs.length;
-  }
-  var upToDollar = cs.substring(0, dollarPos);
-  var fromDollar = cs.substring(dollarPos);
-  // order of attribs stays the same
-  return upToDollar.replace(/\*([0-9a-z]+)/g, function(_, a)
-  {
-    var oldNum = Changeset.parseNum(a);
-    var pair = oldPool.getAttrib(oldNum);
-    var newNum = newPool.putAttrib(pair);
-    return '*' + Changeset.numToString(newNum);
-  }) + fromDollar;
-};
-
-Changeset.makeAttribution = function(text)
-{
-  var assem = Changeset.smartOpAssembler();
-  assem.appendOpWithText('+', text);
-  return assem.toString();
-};
-
-// callable on a changeset, attribution string, or attribs property of an op
-Changeset.eachAttribNumber = function(cs, func)
-{
-  var dollarPos = cs.indexOf('$');
-  if (dollarPos < 0)
-  {
-    dollarPos = cs.length;
-  }
-  var upToDollar = cs.substring(0, dollarPos);
-
-  upToDollar.replace(/\*([0-9a-z]+)/g, function(_, a)
-  {
-    func(Changeset.parseNum(a));
-    return '';
-  });
-};
-
-// callable on a changeset, attribution string, or attribs property of an op,
-// though it may easily create adjacent ops that can be merged.
-Changeset.filterAttribNumbers = function(cs, filter)
-{
-  return Changeset.mapAttribNumbers(cs, filter);
-};
-
-Changeset.mapAttribNumbers = function(cs, func)
-{
-  var dollarPos = cs.indexOf('$');
-  if (dollarPos < 0)
-  {
-    dollarPos = cs.length;
-  }
-  var upToDollar = cs.substring(0, dollarPos);
-
-  var newUpToDollar = upToDollar.replace(/\*([0-9a-z]+)/g, function(s, a)
-  {
-    var n = func(Changeset.parseNum(a));
-    if (n === true)
-    {
-      return s;
-    }
-    else if ((typeof n) === "number")
-    {
-      return '*' + Changeset.numToString(n);
-    }
-    else
-    {
-      return '';
-    }
-  });
-
-  return newUpToDollar + cs.substring(dollarPos);
-};
-
-Changeset.makeAText = function(text, attribs)
-{
-  return {
-    text: text,
-    attribs: (attribs || Changeset.makeAttribution(text))
-  };
-};
-
-Changeset.applyToAText = function(cs, atext, pool)
-{
-  return {
-    text: Changeset.applyToText(cs, atext.text),
-    attribs: Changeset.applyToAttribution(cs, atext.attribs, pool)
-  };
-};
-
-Changeset.cloneAText = function(atext)
-{
-  return {
-    text: atext.text,
-    attribs: atext.attribs
-  };
-};
-
-Changeset.copyAText = function(atext1, atext2)
-{
-  atext2.text = atext1.text;
-  atext2.attribs = atext1.attribs;
-};
-
-Changeset.appendATextToAssembler = function(atext, assem)
-{
-  // intentionally skips last newline char of atext
-  var iter = Changeset.opIterator(atext.attribs);
-  var op = Changeset.newOp();
-  while (iter.hasNext())
-  {
-    iter.next(op);
-    if (!iter.hasNext())
-    {
-      // last op, exclude final newline
-      if (op.lines <= 1)
-      {
-        op.lines = 0;
-        op.chars--;
-        if (op.chars)
-        {
-          assem.append(op);
-        }
-      }
-      else
-      {
-        var nextToLastNewlineEnd = atext.text.lastIndexOf('\n', atext.text.length - 2) + 1;
-        var lastLineLength = atext.text.length - nextToLastNewlineEnd - 1;
-        op.lines--;
-        op.chars -= (lastLineLength + 1);
-        assem.append(op);
-        op.lines = 0;
-        op.chars = lastLineLength;
-        if (op.chars)
-        {
-          assem.append(op);
-        }
-      }
-    }
-    else
-    {
-      assem.append(op);
-    }
-  }
-};
-
-Changeset.prepareForWire = function(cs, pool)
-{
-  var newPool = new AttribPool();
-  var newCs = Changeset.moveOpsToNewPool(cs, pool, newPool);
-  return {
-    translated: newCs,
-    pool: newPool
-  };
-};
-
-Changeset.isIdentity = function(cs)
-{
-  var unpacked = Changeset.unpack(cs);
-  return unpacked.ops == "" && unpacked.oldLen == unpacked.newLen;
-};
-
-Changeset.opAttributeValue = function(op, key, pool)
-{
-  return Changeset.attribsAttributeValue(op.attribs, key, pool);
-};
-
-Changeset.attribsAttributeValue = function(attribs, key, pool)
-{
-  var value = '';
-  if (attribs)
-  {
-    Changeset.eachAttribNumber(attribs, function(n)
-    {
-      if (pool.getAttribKey(n) == key)
-      {
-        value = pool.getAttribValue(n);
-      }
-    });
-  }
-  return value;
-};
-
-Changeset.builder = function(oldLen)
-{
-  var assem = Changeset.smartOpAssembler();
-  var o = Changeset.newOp();
-  var charBank = Changeset.stringAssembler();
-
-  var self = {
-    // attribs are [[key1,value1],[key2,value2],...] or '*0*1...' (no pool needed in latter case)
-    keep: function(N, L, attribs, pool)
-    {
-      o.opcode = '=';
-      o.attribs = (attribs && Changeset.makeAttribsString('=', attribs, pool)) || '';
-      o.chars = N;
-      o.lines = (L || 0);
-      assem.append(o);
-      return self;
-    },
-    keepText: function(text, attribs, pool)
-    {
-      assem.appendOpWithText('=', text, attribs, pool);
-      return self;
-    },
-    insert: function(text, attribs, pool)
-    {
-      assem.appendOpWithText('+', text, attribs, pool);
-      charBank.append(text);
-      return self;
-    },
-    remove: function(N, L)
-    {
-      o.opcode = '-';
-      o.attribs = '';
-      o.chars = N;
-      o.lines = (L || 0);
-      assem.append(o);
-      return self;
-    },
-    toString: function()
-    {
-      assem.endDocument();
-      var newLen = oldLen + assem.getLengthChange();
-      return Changeset.pack(oldLen, newLen, assem.toString(), charBank.toString());
-    }
-  };
-
-  return self;
-};
-
-Changeset.makeAttribsString = function(opcode, attribs, pool)
-{
-  // makeAttribsString(opcode, '*3') or makeAttribsString(opcode, [['foo','bar']], myPool) work
-  if (!attribs)
-  {
-    return '';
-  }
-  else if ((typeof attribs) == "string")
-  {
-    return attribs;
-  }
-  else if (pool && attribs && attribs.length)
-  {
-    if (attribs.length > 1)
-    {
-      attribs = attribs.slice();
-      attribs.sort();
-    }
-    var result = [];
-    for (var i = 0; i < attribs.length; i++)
-    {
-      var pair = attribs[i];
-      if (opcode == '=' || (opcode == '+' && pair[1]))
-      {
-        result.push('*' + Changeset.numToString(pool.putAttrib(pair)));
-      }
-    }
-    return result.join('');
-  }
-};
-
-// like "substring" but on a single-line attribution string
-Changeset.subattribution = function(astr, start, optEnd)
-{
-  var iter = Changeset.opIterator(astr, 0);
-  var assem = Changeset.smartOpAssembler();
-  var attOp = Changeset.newOp();
-  var csOp = Changeset.newOp();
-  var opOut = Changeset.newOp();
-
-  function doCsOp()
-  {
-    if (csOp.chars)
-    {
-      while (csOp.opcode && (attOp.opcode || iter.hasNext()))
-      {
-        if (!attOp.opcode) iter.next(attOp);
-
-        if (csOp.opcode && attOp.opcode && csOp.chars >= attOp.chars && attOp.lines > 0 && csOp.lines <= 0)
-        {
-          csOp.lines++;
-        }
-
-        Changeset._slicerZipperFunc(attOp, csOp, opOut, null);
-        if (opOut.opcode)
-        {
-          assem.append(opOut);
-          opOut.opcode = '';
-        }
-      }
-    }
-  }
-
-  csOp.opcode = '-';
-  csOp.chars = start;
-
-  doCsOp();
-
-  if (optEnd === undefined)
-  {
-    if (attOp.opcode)
-    {
-      assem.append(attOp);
-    }
-    while (iter.hasNext())
-    {
-      iter.next(attOp);
-      assem.append(attOp);
-    }
-  }
-  else
-  {
-    csOp.opcode = '=';
-    csOp.chars = optEnd - start;
-    doCsOp();
-  }
-
-  return assem.toString();
-};
-
-Changeset.inverse = function(cs, lines, alines, pool)
-{
-  // lines and alines are what the changeset is meant to apply to.
-  // They may be arrays or objects with .get(i) and .length methods.
-  // They include final newlines on lines.
-
-  function lines_get(idx)
-  {
-    if (lines.get)
-    {
-      return lines.get(idx);
-    }
-    else
-    {
-      return lines[idx];
-    }
-  }
-
-  function lines_length()
-  {
-    if ((typeof lines.length) == "number")
-    {
-      return lines.length;
-    }
-    else
-    {
-      return lines.length();
-    }
-  }
-
-  function alines_get(idx)
-  {
-    if (alines.get)
-    {
-      return alines.get(idx);
-    }
-    else
-    {
-      return alines[idx];
-    }
-  }
-
-  function alines_length()
-  {
-    if ((typeof alines.length) == "number")
-    {
-      return alines.length;
-    }
-    else
-    {
-      return alines.length();
-    }
-  }
-
-  var curLine = 0;
-  var curChar = 0;
-  var curLineOpIter = null;
-  var curLineOpIterLine;
-  var curLineNextOp = Changeset.newOp('+');
-
-  var unpacked = Changeset.unpack(cs);
-  var csIter = Changeset.opIterator(unpacked.ops);
-  var builder = Changeset.builder(unpacked.newLen);
-
-  function consumeAttribRuns(numChars, func /*(len, attribs, endsLine)*/ )
-  {
-
-    if ((!curLineOpIter) || (curLineOpIterLine != curLine))
-    {
-      // create curLineOpIter and advance it to curChar
-      curLineOpIter = Changeset.opIterator(alines_get(curLine));
-      curLineOpIterLine = curLine;
-      var indexIntoLine = 0;
-      var done = false;
-      while (!done)
-      {
-        curLineOpIter.next(curLineNextOp);
-        if (indexIntoLine + curLineNextOp.chars >= curChar)
-        {
-          curLineNextOp.chars -= (curChar - indexIntoLine);
-          done = true;
-        }
-        else
-        {
-          indexIntoLine += curLineNextOp.chars;
-        }
-      }
-    }
-
-    while (numChars > 0)
-    {
-      if ((!curLineNextOp.chars) && (!curLineOpIter.hasNext()))
-      {
-        curLine++;
-        curChar = 0;
-        curLineOpIterLine = curLine;
-        curLineNextOp.chars = 0;
-        curLineOpIter = Changeset.opIterator(alines_get(curLine));
-      }
-      if (!curLineNextOp.chars)
-      {
-        curLineOpIter.next(curLineNextOp);
-      }
-      var charsToUse = Math.min(numChars, curLineNextOp.chars);
-      func(charsToUse, curLineNextOp.attribs, charsToUse == curLineNextOp.chars && curLineNextOp.lines > 0);
-      numChars -= charsToUse;
-      curLineNextOp.chars -= charsToUse;
-      curChar += charsToUse;
-    }
-
-    if ((!curLineNextOp.chars) && (!curLineOpIter.hasNext()))
-    {
-      curLine++;
-      curChar = 0;
-    }
-  }
-
-  function skip(N, L)
-  {
-    if (L)
-    {
-      curLine += L;
-      curChar = 0;
-    }
-    else
-    {
-      if (curLineOpIter && curLineOpIterLine == curLine)
-      {
-        consumeAttribRuns(N, function()
-        {});
-      }
-      else
-      {
-        curChar += N;
-      }
-    }
-  }
-
-  function nextText(numChars)
-  {
-    var len = 0;
-    var assem = Changeset.stringAssembler();
-    var firstString = lines_get(curLine).substring(curChar);
-    len += firstString.length;
-    assem.append(firstString);
-
-    var lineNum = curLine + 1;
-    while (len < numChars)
-    {
-      var nextString = lines_get(lineNum);
-      len += nextString.length;
-      assem.append(nextString);
-      lineNum++;
-    }
-
-    return assem.toString().substring(0, numChars);
-  }
-
-  function cachedStrFunc(func)
-  {
-    var cache = {};
-    return function(s)
-    {
-      if (!cache[s])
-      {
-        cache[s] = func(s);
-      }
-      return cache[s];
-    };
-  }
-
-  var attribKeys = [];
-  var attribValues = [];
-  while (csIter.hasNext())
-  {
-    var csOp = csIter.next();
-    if (csOp.opcode == '=')
-    {
-      if (csOp.attribs)
-      {
-        attribKeys.length = 0;
-        attribValues.length = 0;
-        Changeset.eachAttribNumber(csOp.attribs, function(n)
-        {
-          attribKeys.push(pool.getAttribKey(n));
-          attribValues.push(pool.getAttribValue(n));
-        });
-        var undoBackToAttribs = cachedStrFunc(function(attribs)
-        {
-          var backAttribs = [];
-          for (var i = 0; i < attribKeys.length; i++)
-          {
-            var appliedKey = attribKeys[i];
-            var appliedValue = attribValues[i];
-            var oldValue = Changeset.attribsAttributeValue(attribs, appliedKey, pool);
-            if (appliedValue != oldValue)
-            {
-              backAttribs.push([appliedKey, oldValue]);
-            }
-          }
-          return Changeset.makeAttribsString('=', backAttribs, pool);
-        });
-        consumeAttribRuns(csOp.chars, function(len, attribs, endsLine)
-        {
-          builder.keep(len, endsLine ? 1 : 0, undoBackToAttribs(attribs));
-        });
-      }
-      else
-      {
-        skip(csOp.chars, csOp.lines);
-        builder.keep(csOp.chars, csOp.lines);
-      }
-    }
-    else if (csOp.opcode == '+')
-    {
-      builder.remove(csOp.chars, csOp.lines);
-    }
-    else if (csOp.opcode == '-')
-    {
-      var textBank = nextText(csOp.chars);
-      var textBankIndex = 0;
-      consumeAttribRuns(csOp.chars, function(len, attribs, endsLine)
-      {
-        builder.insert(textBank.substr(textBankIndex, len), attribs);
-        textBankIndex += len;
-      });
-    }
-  }
-
-  return Changeset.checkRep(builder.toString());
-};
-
-exports.Changeset = Changeset;
-exports.AttribPool = AttribPool;
diff --git a/static/js/linestylefilter.js b/static/js/linestylefilter.js
index d0b5bc6e..4b455724 100644
--- a/static/js/linestylefilter.js
+++ b/static/js/linestylefilter.js
@@ -28,7 +28,7 @@
 // requires: plugins
 // requires: undefined
 
-var Changeset = require('/easysync2').Changeset
+var Changeset = require('/Changeset');
 var plugins = require('/plugins').plugins;
 var map = require('/ace2_common').map;
 
diff --git a/static/js/linestylefilter_client.js b/static/js/linestylefilter_client.js
deleted file mode 100644
index f057e21a..00000000
--- a/static/js/linestylefilter_client.js
+++ /dev/null
@@ -1,343 +0,0 @@
-/**
- * This code is mostly from the old Etherpad. Please help us to comment this code. 
- * This helps other people to understand this code better and helps them to improve it.
- * TL;DR COMMENTS ON THIS FILE ARE HIGHLY APPRECIATED
- */
-
-// DO NOT EDIT THIS FILE, edit infrastructure/ace/www/linestylefilter.js
-// THIS FILE IS ALSO AN APPJET MODULE: etherpad.collab.ace.linestylefilter
-/**
- * Copyright 2009 Google Inc.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS-IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-// requires: easysync2.Changeset
-// requires: top
-// requires: plugins
-// requires: undefined
-
-var Changeset = require('/easysync2_client').Changeset
-var plugins = require('/plugins').plugins;
-var map = require('/ace2_common').map;
-
-var linestylefilter = {};
-
-linestylefilter.ATTRIB_CLASSES = {
-  'bold': 'tag:b',
-  'italic': 'tag:i',
-  'underline': 'tag:u',
-  'strikethrough': 'tag:s'
-};
-
-linestylefilter.getAuthorClassName = function(author)
-{
-  return "author-" + author.replace(/[^a-y0-9]/g, function(c)
-  {
-    if (c == ".") return "-";
-    return 'z' + c.charCodeAt(0) + 'z';
-  });
-};
-
-// lineLength is without newline; aline includes newline,
-// but may be falsy if lineLength == 0
-linestylefilter.getLineStyleFilter = function(lineLength, aline, textAndClassFunc, apool)
-{
-
-  var plugins_ = plugins;
-
-  if (lineLength == 0) return textAndClassFunc;
-
-  var nextAfterAuthorColors = textAndClassFunc;
-
-  var authorColorFunc = (function()
-  {
-    var lineEnd = lineLength;
-    var curIndex = 0;
-    var extraClasses;
-    var leftInAuthor;
-
-    function attribsToClasses(attribs)
-    {
-      var classes = '';
-      Changeset.eachAttribNumber(attribs, function(n)
-      {
-        var key = apool.getAttribKey(n);
-        if (key)
-        {
-          var value = apool.getAttribValue(n);
-          if (value)
-          {
-            if (key == 'author')
-            {
-              classes += ' ' + linestylefilter.getAuthorClassName(value);
-            }
-            else if (key == 'list')
-            {
-              classes += ' list:' + value;
-            }
-            else if (key == 'start')
-            {
-              classes += ' start:' + value;
-            }
-            else if (linestylefilter.ATTRIB_CLASSES[key])
-            {
-              classes += ' ' + linestylefilter.ATTRIB_CLASSES[key];
-            }
-            else
-            {
-              classes += plugins_.callHookStr("aceAttribsToClasses", {
-                linestylefilter: linestylefilter,
-                key: key,
-                value: value
-              }, " ", " ", "");
-            }
-          }
-        }
-      });
-      return classes.substring(1);
-    }
-
-    var attributionIter = Changeset.opIterator(aline);
-    var nextOp, nextOpClasses;
-
-    function goNextOp()
-    {
-      nextOp = attributionIter.next();
-      nextOpClasses = (nextOp.opcode && attribsToClasses(nextOp.attribs));
-    }
-    goNextOp();
-
-    function nextClasses()
-    {
-      if (curIndex < lineEnd)
-      {
-        extraClasses = nextOpClasses;
-        leftInAuthor = nextOp.chars;
-        goNextOp();
-        while (nextOp.opcode && nextOpClasses == extraClasses)
-        {
-          leftInAuthor += nextOp.chars;
-          goNextOp();
-        }
-      }
-    }
-    nextClasses();
-
-    return function(txt, cls)
-    {
-      while (txt.length > 0)
-      {
-        if (leftInAuthor <= 0)
-        {
-          // prevent infinite loop if something funny's going on
-          return nextAfterAuthorColors(txt, cls);
-        }
-        var spanSize = txt.length;
-        if (spanSize > leftInAuthor)
-        {
-          spanSize = leftInAuthor;
-        }
-        var curTxt = txt.substring(0, spanSize);
-        txt = txt.substring(spanSize);
-        nextAfterAuthorColors(curTxt, (cls && cls + " ") + extraClasses);
-        curIndex += spanSize;
-        leftInAuthor -= spanSize;
-        if (leftInAuthor == 0)
-        {
-          nextClasses();
-        }
-      }
-    };
-  })();
-  return authorColorFunc;
-};
-
-linestylefilter.getAtSignSplitterFilter = function(lineText, textAndClassFunc)
-{
-  var at = /@/g;
-  at.lastIndex = 0;
-  var splitPoints = null;
-  var execResult;
-  while ((execResult = at.exec(lineText)))
-  {
-    if (!splitPoints)
-    {
-      splitPoints = [];
-    }
-    splitPoints.push(execResult.index);
-  }
-
-  if (!splitPoints) return textAndClassFunc;
-
-  return linestylefilter.textAndClassFuncSplitter(textAndClassFunc, splitPoints);
-};
-
-linestylefilter.getRegexpFilter = function(regExp, tag)
-{
-  return function(lineText, textAndClassFunc)
-  {
-    regExp.lastIndex = 0;
-    var regExpMatchs = null;
-    var splitPoints = null;
-    var execResult;
-    while ((execResult = regExp.exec(lineText)))
-    {
-      if (!regExpMatchs)
-      {
-        regExpMatchs = [];
-        splitPoints = [];
-      }
-      var startIndex = execResult.index;
-      var regExpMatch = execResult[0];
-      regExpMatchs.push([startIndex, regExpMatch]);
-      splitPoints.push(startIndex, startIndex + regExpMatch.length);
-    }
-
-    if (!regExpMatchs) return textAndClassFunc;
-
-    function regExpMatchForIndex(idx)
-    {
-      for (var k = 0; k < regExpMatchs.length; k++)
-      {
-        var u = regExpMatchs[k];
-        if (idx >= u[0] && idx < u[0] + u[1].length)
-        {
-          return u[1];
-        }
-      }
-      return false;
-    }
-
-    var handleRegExpMatchsAfterSplit = (function()
-    {
-      var curIndex = 0;
-      return function(txt, cls)
-      {
-        var txtlen = txt.length;
-        var newCls = cls;
-        var regExpMatch = regExpMatchForIndex(curIndex);
-        if (regExpMatch)
-        {
-          newCls += " " + tag + ":" + regExpMatch;
-        }
-        textAndClassFunc(txt, newCls);
-        curIndex += txtlen;
-      };
-    })();
-
-    return linestylefilter.textAndClassFuncSplitter(handleRegExpMatchsAfterSplit, splitPoints);
-  };
-};
-
-
-linestylefilter.REGEX_WORDCHAR = /[\u0030-\u0039\u0041-\u005A\u0061-\u007A\u00C0-\u00D6\u00D8-\u00F6\u00F8-\u00FF\u0100-\u1FFF\u3040-\u9FFF\uF900-\uFDFF\uFE70-\uFEFE\uFF10-\uFF19\uFF21-\uFF3A\uFF41-\uFF5A\uFF66-\uFFDC]/;
-linestylefilter.REGEX_URLCHAR = new RegExp('(' + /[-:@a-zA-Z0-9_.,~%+\/\\?=&#;()$]/.source + '|' + linestylefilter.REGEX_WORDCHAR.source + ')');
-linestylefilter.REGEX_URL = new RegExp(/(?:(?:https?|s?ftp|ftps|file|smb|afp|nfs|(x-)?man|gopher|txmt):\/\/|mailto:|www\.)/.source + linestylefilter.REGEX_URLCHAR.source + '*(?![:.,;])' + linestylefilter.REGEX_URLCHAR.source, 'g');
-linestylefilter.getURLFilter = linestylefilter.getRegexpFilter(
-linestylefilter.REGEX_URL, 'url');
-
-linestylefilter.textAndClassFuncSplitter = function(func, splitPointsOpt)
-{
-  var nextPointIndex = 0;
-  var idx = 0;
-
-  // don't split at 0
-  while (splitPointsOpt && nextPointIndex < splitPointsOpt.length && splitPointsOpt[nextPointIndex] == 0)
-  {
-    nextPointIndex++;
-  }
-
-  function spanHandler(txt, cls)
-  {
-    if ((!splitPointsOpt) || nextPointIndex >= splitPointsOpt.length)
-    {
-      func(txt, cls);
-      idx += txt.length;
-    }
-    else
-    {
-      var splitPoints = splitPointsOpt;
-      var pointLocInSpan = splitPoints[nextPointIndex] - idx;
-      var txtlen = txt.length;
-      if (pointLocInSpan >= txtlen)
-      {
-        func(txt, cls);
-        idx += txt.length;
-        if (pointLocInSpan == txtlen)
-        {
-          nextPointIndex++;
-        }
-      }
-      else
-      {
-        if (pointLocInSpan > 0)
-        {
-          func(txt.substring(0, pointLocInSpan), cls);
-          idx += pointLocInSpan;
-        }
-        nextPointIndex++;
-        // recurse
-        spanHandler(txt.substring(pointLocInSpan), cls);
-      }
-    }
-  }
-  return spanHandler;
-};
-
-linestylefilter.getFilterStack = function(lineText, textAndClassFunc, browser)
-{
-  var func = linestylefilter.getURLFilter(lineText, textAndClassFunc);
-
-  var plugins_ = plugins;
-
-  var hookFilters = plugins_.callHook("aceGetFilterStack", {
-    linestylefilter: linestylefilter,
-    browser: browser
-  });
-  map(hookFilters, function(hookFilter)
-  {
-    func = hookFilter(lineText, func);
-  });
-
-  if (browser !== undefined && browser.msie)
-  {
-    // IE7+ will take an e-mail address like <foo@bar.com> and linkify it to foo@bar.com.
-    // We then normalize it back to text with no angle brackets.  It's weird.  So always
-    // break spans at an "at" sign.
-    func = linestylefilter.getAtSignSplitterFilter(
-    lineText, func);
-  }
-  return func;
-};
-
-// domLineObj is like that returned by domline.createDomLine
-linestylefilter.populateDomLine = function(textLine, aline, apool, domLineObj)
-{
-  // remove final newline from text if any
-  var text = textLine;
-  if (text.slice(-1) == '\n')
-  {
-    text = text.substring(0, text.length - 1);
-  }
-
-  function textAndClassFunc(tokenText, tokenClass)
-  {
-    domLineObj.appendSpan(tokenText, tokenClass);
-  }
-
-  var func = linestylefilter.getFilterStack(text, textAndClassFunc);
-  func = linestylefilter.getLineStyleFilter(text.length, aline, func, apool);
-  func(text, '');
-};
-
-exports.linestylefilter = linestylefilter;
diff --git a/static/js/pad.js b/static/js/pad.js
index 9dab9c61..eb480080 100644
--- a/static/js/pad.js
+++ b/static/js/pad.js
@@ -46,47 +46,9 @@ var padsavedrevs = require('/pad_savedrevs').padsavedrevs;
 var paduserlist = require('/pad_userlist').paduserlist;
 var padutils = require('/pad_utils').padutils;
 
-function createCookie(name, value, days, path)
-{
-  if (days)
-  {
-    var date = new Date();
-    date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
-    var expires = "; expires=" + date.toGMTString();
-  }
-  else var expires = "";
-  
-  if(!path)
-    path = "/";
-  
-  document.cookie = name + "=" + value + expires + "; path=" + path;
-}
-
-function readCookie(name)
-{
-  var nameEQ = name + "=";
-  var ca = document.cookie.split(';');
-  for (var i = 0; i < ca.length; i++)
-  {
-    var c = ca[i];
-    while (c.charAt(0) == ' ') c = c.substring(1, c.length);
-    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length, c.length);
-  }
-  return null;
-}
-
-function randomString()
-{
-  var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
-  var string_length = 20;
-  var randomstring = '';
-  for (var i = 0; i < string_length; i++)
-  {
-    var rnum = Math.floor(Math.random() * chars.length);
-    randomstring += chars.substring(rnum, rnum + 1);
-  }
-  return "t." + randomstring;
-}
+var createCookie = require('/pad_utils').createCookie;
+var readCookie = require('/pad_utils').readCookie;
+var randomString = require('/pad_utils').randomString;
 
 function getParams()
 {
@@ -210,7 +172,7 @@ function handshake()
     var token = readCookie("token");
     if (token == null)
     {
-      token = randomString();
+      token = "t." + randomString();
       createCookie("token", token, 60);
     }
     
diff --git a/static/js/pad_utils.js b/static/js/pad_utils.js
index 071185a8..fb538211 100644
--- a/static/js/pad_utils.js
+++ b/static/js/pad_utils.js
@@ -20,17 +20,58 @@
  * limitations under the License.
  */
 
+var Security = require('/security');
+
+/**
+ * Generates a random String with the given length. Is needed to generate the Author, Group, readonly, session Ids
+ */
+
+function randomString(len)
+{
+  var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
+  var randomstring = '';
+  len = len || 20
+  for (var i = 0; i < len; i++)
+  {
+    var rnum = Math.floor(Math.random() * chars.length);
+    randomstring += chars.substring(rnum, rnum + 1);
+  }
+  return randomstring;
+}
+
+function createCookie(name, value, days, path)
+{
+  if (days)
+  {
+    var date = new Date();
+    date.setTime(date.getTime() + (days * 24 * 60 * 60 * 1000));
+    var expires = "; expires=" + date.toGMTString();
+  }
+  else var expires = "";
+
+  if(!path)
+    path = "/";
+
+  document.cookie = name + "=" + value + expires + "; path=" + path;
+}
+
+function readCookie(name)
+{
+  var nameEQ = name + "=";
+  var ca = document.cookie.split(';');
+  for (var i = 0; i < ca.length; i++)
+  {
+    var c = ca[i];
+    while (c.charAt(0) == ' ') c = c.substring(1, c.length);
+    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length, c.length);
+  }
+  return null;
+}
+
 var padutils = {
   escapeHtml: function(x)
   {
-    return String(x).replace(/[&"<>]/g, function (c) {
-      return {
-        '&': '&amp;',
-        '"': '&quot;',
-        '<': '&lt;',
-        '>': '&gt;'
-      }[c] || c;
-    });
+    return Security.escapeHTML(String(x));
   },
   uniqueId: function()
   {
@@ -159,7 +200,7 @@ var padutils = {
     {
       if (i > idx)
       {
-        pieces.push(padutils.escapeHtml(text.substring(idx, i)));
+        pieces.push(Security.escapeHTML(text.substring(idx, i)));
         idx = i;
       }
     }
@@ -170,7 +211,7 @@ var padutils = {
         var startIndex = urls[j][0];
         var href = urls[j][1];
         advanceTo(startIndex);
-        pieces.push('<a ', (target ? 'target="' + target + '" ' : ''), 'href="', padutils.escapeHtml(href), '">');
+        pieces.push('<a ', (target ? 'target="' + Security.escapeHTMLAttribute(target) + '" ' : ''), 'href="', Security.escapeHTMLAttribute(href), '">');
         advanceTo(startIndex + href.length);
         pieces.push('</a>');
       }
@@ -481,4 +522,7 @@ padutils.setupGlobalExceptionHandler = setupGlobalExceptionHandler;
 
 padutils.binarySearch = require('/ace2_common').binarySearch;
 
+exports.randomString = randomString;
+exports.createCookie = createCookie;
+exports.readCookie = readCookie;
 exports.padutils = padutils;
diff --git a/static/js/security.js b/static/js/security.js
new file mode 100644
index 00000000..6f42d051
--- /dev/null
+++ b/static/js/security.js
@@ -0,0 +1,54 @@
+/**
+ * Copyright 2009 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS-IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+var HTML_ENTITY_MAP = {
+  '&': '&amp;'
+, '<': '&lt;'
+, '>': '&gt;'
+, '"': '&quot;'
+, "'": '&#x27;'
+, '/': '&#x2F;'
+};
+
+// OSWASP Guidlines: &, <, >, ", ' plus forward slash.
+var HTML_CHARACTERS_EXPRESSION = /[&"'<>\/]/g;
+function escapeHTML(text) {
+  return text && text.replace(HTML_CHARACTERS_EXPRESSION, function (c) {
+    return HTML_ENTITY_MAP[c] || c;
+  });
+}
+
+// OSWASP Guidlines: escape all non alphanumeric characters in ASCII space.
+var HTML_ATTRIBUTE_CHARACTERS_EXPRESSION =
+    /[\x00-\x2F\x3A-\x40\5B-\x60\x7B-\xFF]/g;
+function escapeHTMLAttribute(text) {
+  return text && text.replace(HTML_ATTRIBUTE_CHARACTERS_EXPRESSION, function (c) {
+    return "&#x" + ('00' + c.charCodeAt(0).toString(16)).slice(-2) + ";";
+  });
+};
+
+// OSWASP Guidlines: escape all non alphanumeric characters in ASCII space.
+var JAVASCRIPT_CHARACTERS_EXPRESSION =
+    /[\x00-\x2F\x3A-\x40\5B-\x60\x7B-\xFF]/g;
+function escapeJavaScriptData(text) {
+  return text && text.replace(JAVASCRIPT_CHARACTERS_EXPRESSION, function (c) {
+    return "\\x" + ('00' + c.charCodeAt(0).toString(16)).slice(-2);
+  });
+}
+
+exports.escapeHTML = escapeHTML;
+exports.escapeHTMLAttribute = escapeHTMLAttribute;
+exports.escapeJavaScriptData = escapeJavaScriptData;
diff --git a/static/js/timeslider.js b/static/js/timeslider.js
index d2fce8fd..143ef328 100644
--- a/static/js/timeslider.js
+++ b/static/js/timeslider.js
@@ -26,39 +26,9 @@ require('/jquery');
 JSON = require('/json2');
 require('/undo-xpopup');
 
-function createCookie(name,value,days)
-{
-  if (days) {
-    var date = new Date();
-    date.setTime(date.getTime()+(days*24*60*60*1000));
-    var expires = "; expires="+date.toGMTString();
-  }
-  else var expires = "";
-  document.cookie = name+"="+value+expires+"; path=/";
-}
-
-function readCookie(name)
-{
-  var nameEQ = name + "=";
-  var ca = document.cookie.split(';');
-  for(var i=0;i < ca.length;i++) {
-    var c = ca[i];
-    while (c.charAt(0)==' ') c = c.substring(1,c.length);
-    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
-  }
-  return null;
-}
-
-function randomString() {
-  var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
-  var string_length = 20;
-  var randomstring = '';
-  for (var i=0; i<string_length; i++) {
-    var rnum = Math.floor(Math.random() * chars.length);
-    randomstring += chars.substring(rnum,rnum+1);
-  }
-  return "t." + randomstring;
-}
+var createCookie = require('/pad_utils').createCookie;
+var readCookie = require('/pad_utils').readCookie;
+var randomString = require('/pad_utils').randomString;
 
 var socket, token, padId, export_links;
 
@@ -79,7 +49,7 @@ function init() {
     token = readCookie("token");
     if(token == null)
     {
-      token = randomString();
+      token = "t." + randomString();
       createCookie("token", token, 60);
     }
 
diff --git a/static/js/undomodule.js b/static/js/undomodule.js
index aff41a70..886cbdf0 100644
--- a/static/js/undomodule.js
+++ b/static/js/undomodule.js
@@ -20,7 +20,7 @@
  * limitations under the License.
  */
 
-var Changeset = require('/easysync2').Changeset;
+var Changeset = require('/Changeset');
 var extend = require('/ace2_common').extend;
 
 var undoModule = (function()