// All functions that need access to the editor's state live inside
// the CodeMirror function. Below that, at the bottom of the file,
// some utilities are defined.

// CodeMirror is the only global var we claim
var CodeMirror = (function() {
  // This is the function that produces an editor instance. It's
  // closure is used to store the editor state.
  function CodeMirror(place, givenOptions) {
    // Determine effective options based on given values and defaults.
    var options = {}, defaults = CodeMirror.defaults;
    for (var opt in defaults)
      if (defaults.hasOwnProperty(opt))
        options[opt] = (givenOptions && givenOptions.hasOwnProperty(opt) ? givenOptions : defaults)[opt];

    var targetDocument = options["document"];
    // The element in which the editor lives.
    var wrapper = targetDocument.createElement("div");
    wrapper.className = "CodeMirror" + (options.lineWrapping ? " CodeMirror-wrap" : "");
    // This mess creates the base DOM structure for the editor.
    wrapper.innerHTML =
      '<div style="overflow: hidden; position: relative; width: 3px; height: 0px;">' + // Wraps and hides input textarea
        '<textarea style="position: absolute; padding: 0; width: 1px; height: 1em" wrap="off" ' +
          'autocorrect="off" autocapitalize="off"></textarea></div>' +
      '<div class="CodeMirror-scroll" tabindex="-1">' +
        '<div style="position: relative">' + // Set to the height of the text, causes scrolling
          '<div style="position: relative">' + // Moved around its parent to cover visible view
            '<div class="CodeMirror-gutter"><div class="CodeMirror-gutter-text"></div></div>' +
            // Provides positioning relative to (visible) text origin
            '<div class="CodeMirror-lines"><div style="position: relative; z-index: 0">' +
              '<div style="position: absolute; width: 100%; height: 0; overflow: hidden; visibility: hidden; outline: 5px auto none"></div>' +
              '<pre class="CodeMirror-cursor">&#160;</pre>' + // Absolutely positioned blinky cursor
              '<div style="position: relative; z-index: -1"></div><div></div>' + // DIVs containing the selection and the actual code
            '</div></div></div></div></div>';
    if (place.appendChild) place.appendChild(wrapper); else place(wrapper);
    // I've never seen more elegant code in my life.
    var inputDiv = wrapper.firstChild, input = inputDiv.firstChild,
        scroller = wrapper.lastChild, code = scroller.firstChild,
        mover = code.firstChild, gutter = mover.firstChild, gutterText = gutter.firstChild,
        lineSpace = gutter.nextSibling.firstChild, measure = lineSpace.firstChild,
        cursor = measure.nextSibling, selectionDiv = cursor.nextSibling,
        lineDiv = selectionDiv.nextSibling;
    themeChanged();
    // Needed to hide big blue blinking cursor on Mobile Safari
    if (ios) input.style.width = "0px";
    if (!webkit) lineSpace.draggable = true;
    lineSpace.style.outline = "none";
    if (options.tabindex != null) input.tabIndex = options.tabindex;
    if (!options.gutter && !options.lineNumbers) gutter.style.display = "none";

    // Check for problem with IE innerHTML not working when we have a
    // P (or similar) parent node.
    try { stringWidth("x"); }
    catch (e) {
      if (e.message.match(/runtime/i))
        e = new Error("A CodeMirror inside a P-style element does not work in Internet Explorer. (innerHTML bug)");
      throw e;
    }

    // Delayed object wrap timeouts, making sure only one is active. blinker holds an interval.
    var poll = new Delayed(), highlight = new Delayed(), blinker;

    // mode holds a mode API object. doc is the tree of Line objects,
    // work an array of lines that should be parsed, and history the
    // undo history (instance of History constructor).
    var mode, doc = new BranchChunk([new LeafChunk([new Line("")])]), work, focused;
    loadMode();
    // The selection. These are always maintained to point at valid
    // positions. Inverted is used to remember that the user is
    // selecting bottom-to-top.
    var sel = {from: {line: 0, ch: 0}, to: {line: 0, ch: 0}, inverted: false};
    // Selection-related flags. shiftSelecting obviously tracks
    // whether the user is holding shift.
    var shiftSelecting, lastClick, lastDoubleClick, lastScrollPos = 0, draggingText,
        overwrite = false, suppressEdits = false;
    // Variables used by startOperation/endOperation to track what
    // happened during the operation.
    var updateInput, userSelChange, changes, textChanged, selectionChanged, leaveInputAlone,
        gutterDirty, callbacks;
    // Current visible range (may be bigger than the view window).
    var displayOffset = 0, showingFrom = 0, showingTo = 0, lastSizeC = 0;
    // bracketHighlighted is used to remember that a backet has been
    // marked.
    var bracketHighlighted;
    // Tracks the maximum line length so that the horizontal scrollbar
    // can be kept static when scrolling.
    var maxLine = "", maxWidth, tabText = computeTabText();

    // Initialize the content.
    operation(function(){setValue(options.value || ""); updateInput = false;})();
    var history = new History();

    // Register our event handlers.
    connect(scroller, "mousedown", operation(onMouseDown));
    connect(scroller, "dblclick", operation(onDoubleClick));
    connect(lineSpace, "dragstart", onDragStart);
    connect(lineSpace, "selectstart", e_preventDefault);
    // Gecko browsers fire contextmenu *after* opening the menu, at
    // which point we can't mess with it anymore. Context menu is
    // handled in onMouseDown for Gecko.
    if (!gecko) connect(scroller, "contextmenu", onContextMenu);
    connect(scroller, "scroll", function() {
      lastScrollPos = scroller.scrollTop;
      updateDisplay([]);
      if (options.fixedGutter) gutter.style.left = scroller.scrollLeft + "px";
      if (options.onScroll) options.onScroll(instance);
    });
    connect(window, "resize", function() {updateDisplay(true);});
    connect(input, "keyup", operation(onKeyUp));
    connect(input, "input", fastPoll);
    connect(input, "keydown", operation(onKeyDown));
    connect(input, "keypress", operation(onKeyPress));
    connect(input, "focus", onFocus);
    connect(input, "blur", onBlur);

    connect(scroller, "dragenter", e_stop);
    connect(scroller, "dragover", e_stop);
    connect(scroller, "drop", operation(onDrop));
    connect(scroller, "paste", function(){focusInput(); fastPoll();});
    connect(input, "paste", fastPoll);
    connect(input, "cut", operation(function(){
      if (!options.readOnly) replaceSelection("");
    }));

    // IE throws unspecified error in certain cases, when
    // trying to access activeElement before onload
    var hasFocus; try { hasFocus = (targetDocument.activeElement == input); } catch(e) { }
    if (hasFocus) setTimeout(onFocus, 20);
    else onBlur();

    function isLine(l) {return l >= 0 && l < doc.size;}
    // The instance object that we'll return. Mostly calls out to
    // local functions in the CodeMirror function. Some do some extra
    // range checking and/or clipping. operation is used to wrap the
    // call so that changes it makes are tracked, and the display is
    // updated afterwards.
    var instance = wrapper.CodeMirror = {
      getValue: getValue,
      setValue: operation(setValue),
      getSelection: getSelection,
      replaceSelection: operation(replaceSelection),
      focus: function(){focusInput(); onFocus(); fastPoll();},
      setOption: function(option, value) {
        var oldVal = options[option];
        options[option] = value;
        if (option == "mode" || option == "indentUnit") loadMode();
        else if (option == "readOnly" && value == "nocursor") {onBlur(); input.blur();}
        else if (option == "readOnly" && !value) {resetInput(true);}
        else if (option == "theme") themeChanged();
        else if (option == "lineWrapping" && oldVal != value) operation(wrappingChanged)();
        else if (option == "tabSize") operation(tabsChanged)();
        if (option == "lineNumbers" || option == "gutter" || option == "firstLineNumber" || option == "theme") {
          gutterChanged();
          updateDisplay(true);
        }
      },
      getOption: function(option) {return options[option];},
      undo: operation(undo),
      redo: operation(redo),
      indentLine: operation(function(n, dir) {
        if (typeof dir != "string") {
          if (dir == null) dir = options.smartIndent ? "smart" : "prev";
          else dir = dir ? "add" : "subtract";
        }
        if (isLine(n)) indentLine(n, dir);
      }),
      indentSelection: operation(indentSelected),
      historySize: function() {return {undo: history.done.length, redo: history.undone.length};},
      clearHistory: function() {history = new History();},
      matchBrackets: operation(function(){matchBrackets(true);}),
      getTokenAt: operation(function(pos) {
        pos = clipPos(pos);
        return getLine(pos.line).getTokenAt(mode, getStateBefore(pos.line), pos.ch);
      }),
      getStateAfter: function(line) {
        line = clipLine(line == null ? doc.size - 1: line);
        return getStateBefore(line + 1);
      },
      cursorCoords: function(start){
        if (start == null) start = sel.inverted;
        return pageCoords(start ? sel.from : sel.to);
      },
      charCoords: function(pos){return pageCoords(clipPos(pos));},
      coordsChar: function(coords) {
        var off = eltOffset(lineSpace);
        return coordsChar(coords.x - off.left, coords.y - off.top);
      },
      markText: operation(markText),
      setBookmark: setBookmark,
      setMarker: operation(addGutterMarker),
      clearMarker: operation(removeGutterMarker),
      setLineClass: operation(setLineClass),
      hideLine: operation(function(h) {return setLineHidden(h, true);}),
      showLine: operation(function(h) {return setLineHidden(h, false);}),
      onDeleteLine: function(line, f) {
        if (typeof line == "number") {
          if (!isLine(line)) return null;
          line = getLine(line);
        }
        (line.handlers || (line.handlers = [])).push(f);
        return line;
      },
      lineInfo: lineInfo,
      addWidget: function(pos, node, scroll, vert, horiz) {
        pos = localCoords(clipPos(pos));
        var top = pos.yBot, left = pos.x;
        node.style.position = "absolute";
        code.appendChild(node);
        if (vert == "over") top = pos.y;
        else if (vert == "near") {
          var vspace = Math.max(scroller.offsetHeight, doc.height * textHeight()),
              hspace = Math.max(code.clientWidth, lineSpace.clientWidth) - paddingLeft();
          if (pos.yBot + node.offsetHeight > vspace && pos.y > node.offsetHeight)
            top = pos.y - node.offsetHeight;
          if (left + node.offsetWidth > hspace)
            left = hspace - node.offsetWidth;
        }
        node.style.top = (top + paddingTop()) + "px";
        node.style.left = node.style.right = "";
        if (horiz == "right") {
          left = code.clientWidth - node.offsetWidth;
          node.style.right = "0px";
        } else {
          if (horiz == "left") left = 0;
          else if (horiz == "middle") left = (code.clientWidth - node.offsetWidth) / 2;
          node.style.left = (left + paddingLeft()) + "px";
        }
        if (scroll)
          scrollIntoView(left, top, left + node.offsetWidth, top + node.offsetHeight);
      },

      lineCount: function() {return doc.size;},
      clipPos: clipPos,
      getCursor: function(start) {
        if (start == null) start = sel.inverted;
        return copyPos(start ? sel.from : sel.to);
      },
      somethingSelected: function() {return !posEq(sel.from, sel.to);},
      setCursor: operation(function(line, ch, user) {
        if (ch == null && typeof line.line == "number") setCursor(line.line, line.ch, user);
        else setCursor(line, ch, user);
      }),
      setSelection: operation(function(from, to, user) {
        (user ? setSelectionUser : setSelection)(clipPos(from), clipPos(to || from));
      }),
      getLine: function(line) {if (isLine(line)) return getLine(line).text;},
      getLineHandle: function(line) {if (isLine(line)) return getLine(line);},
      setLine: operation(function(line, text) {
        if (isLine(line)) replaceRange(text, {line: line, ch: 0}, {line: line, ch: getLine(line).text.length});
      }),
      removeLine: operation(function(line) {
        if (isLine(line)) replaceRange("", {line: line, ch: 0}, clipPos({line: line+1, ch: 0}));
      }),
      replaceRange: operation(replaceRange),
      getRange: function(from, to) {return getRange(clipPos(from), clipPos(to));},

      execCommand: function(cmd) {return commands[cmd](instance);},
      // Stuff used by commands, probably not much use to outside code.
      moveH: operation(moveH),
      deleteH: operation(deleteH),
      moveV: operation(moveV),
      toggleOverwrite: function() {overwrite = !overwrite;},

      posFromIndex: function(off) {
        var lineNo = 0, ch;
        doc.iter(0, doc.size, function(line) {
          var sz = line.text.length + 1;
          if (sz > off) { ch = off; return true; }
          off -= sz;
          ++lineNo;
        });
        return clipPos({line: lineNo, ch: ch});
      },
      indexFromPos: function (coords) {
        if (coords.line < 0 || coords.ch < 0) return 0;
        var index = coords.ch;
        doc.iter(0, coords.line, function (line) {
          index += line.text.length + 1;
        });
        return index;
      },
      scrollTo: function(x, y) {
        if (x != null) scroller.scrollLeft = x;
        if (y != null) scroller.scrollTop = y;
        updateDisplay([]);
      },

      operation: function(f){return operation(f)();},
      refresh: function(){
        updateDisplay(true);
        if (scroller.scrollHeight > lastScrollPos)
          scroller.scrollTop = lastScrollPos;
      },
      getInputField: function(){return input;},
      getWrapperElement: function(){return wrapper;},
      getScrollerElement: function(){return scroller;},
      getGutterElement: function(){return gutter;}
    };

    function getLine(n) { return getLineAt(doc, n); }
    function updateLineHeight(line, height) {
      gutterDirty = true;
      var diff = height - line.height;
      for (var n = line; n; n = n.parent) n.height += diff;
    }

    function setValue(code) {
      var top = {line: 0, ch: 0};
      updateLines(top, {line: doc.size - 1, ch: getLine(doc.size-1).text.length},
                  splitLines(code), top, top);
      updateInput = true;
    }
    function getValue(code) {
      var text = [];
      doc.iter(0, doc.size, function(line) { text.push(line.text); });
      return text.join("\n");
    }

    function onMouseDown(e) {
      setShift(e_prop(e, "shiftKey"));
      // Check whether this is a click in a widget
      for (var n = e_target(e); n != wrapper; n = n.parentNode)
        if (n.parentNode == code && n != mover) return;

      // See if this is a click in the gutter
      for (var n = e_target(e); n != wrapper; n = n.parentNode)
        if (n.parentNode == gutterText) {
          if (options.onGutterClick)
            options.onGutterClick(instance, indexOf(gutterText.childNodes, n) + showingFrom, e);
          return e_preventDefault(e);
        }

      var start = posFromMouse(e);

      switch (e_button(e)) {
      case 3:
        if (gecko && !mac) onContextMenu(e);
        return;
      case 2:
        if (start) setCursor(start.line, start.ch, true);
        return;
      }
      // For button 1, if it was clicked inside the editor
      // (posFromMouse returning non-null), we have to adjust the
      // selection.
      if (!start) {if (e_target(e) == scroller) e_preventDefault(e); return;}

      if (!focused) onFocus();

      var now = +new Date;
      if (lastDoubleClick && lastDoubleClick.time > now - 400 && posEq(lastDoubleClick.pos, start)) {
        e_preventDefault(e);
        setTimeout(focusInput, 20);
        return selectLine(start.line);
      } else if (lastClick && lastClick.time > now - 400 && posEq(lastClick.pos, start)) {
        lastDoubleClick = {time: now, pos: start};
        e_preventDefault(e);
        return selectWordAt(start);
      } else { lastClick = {time: now, pos: start}; }

      var last = start, going;
      if (dragAndDrop && !options.readOnly && !posEq(sel.from, sel.to) &&
          !posLess(start, sel.from) && !posLess(sel.to, start)) {
        // Let the drag handler handle this.
        if (webkit) lineSpace.draggable = true;
        var up = connect(targetDocument, "mouseup", operation(function(e2) {
          if (webkit) lineSpace.draggable = false;
          draggingText = false;
          up();
          if (Math.abs(e.clientX - e2.clientX) + Math.abs(e.clientY - e2.clientY) < 10) {
            e_preventDefault(e2);
            setCursor(start.line, start.ch, true);
            focusInput();
          }
        }), true);
        draggingText = true;
        return;
      }
      e_preventDefault(e);
      setCursor(start.line, start.ch, true);

      function extend(e) {
        var cur = posFromMouse(e, true);
        if (cur && !posEq(cur, last)) {
          if (!focused) onFocus();
          last = cur;
          setSelectionUser(start, cur);
          updateInput = false;
          var visible = visibleLines();
          if (cur.line >= visible.to || cur.line < visible.from)
            going = setTimeout(operation(function(){extend(e);}), 150);
        }
      }

      var move = connect(targetDocument, "mousemove", operation(function(e) {
        clearTimeout(going);
        e_preventDefault(e);
        extend(e);
      }), true);
      var up = connect(targetDocument, "mouseup", operation(function(e) {
        clearTimeout(going);
        var cur = posFromMouse(e);
        if (cur) setSelectionUser(start, cur);
        e_preventDefault(e);
        focusInput();
        updateInput = true;
        move(); up();
      }), true);
    }
    function onDoubleClick(e) {
      for (var n = e_target(e); n != wrapper; n = n.parentNode)
        if (n.parentNode == gutterText) return e_preventDefault(e);
      var start = posFromMouse(e);
      if (!start) return;
      lastDoubleClick = {time: +new Date, pos: start};
      e_preventDefault(e);
      selectWordAt(start);
    }
    function onDrop(e) {
      e.preventDefault();
      var pos = posFromMouse(e, true), files = e.dataTransfer.files;
      if (!pos || options.readOnly) return;
      if (files && files.length && window.FileReader && window.File) {
        function loadFile(file, i) {
          var reader = new FileReader;
          reader.onload = function() {
            text[i] = reader.result;
            if (++read == n) {
	      pos = clipPos(pos);
	      operation(function() {
                var end = replaceRange(text.join(""), pos, pos);
                setSelectionUser(pos, end);
              })();
	    }
          };
          reader.readAsText(file);
        }
        var n = files.length, text = Array(n), read = 0;
        for (var i = 0; i < n; ++i) loadFile(files[i], i);
      }
      else {
        try {
          var text = e.dataTransfer.getData("Text");
          if (text) {
            var curFrom = sel.from, curTo = sel.to;
            setSelectionUser(pos, pos);
            if (draggingText) replaceRange("", curFrom, curTo);
            replaceSelection(text);
	    focusInput();
	  }
        }
        catch(e){}
      }
    }
    function onDragStart(e) {
      var txt = getSelection();
      // This will reset escapeElement
      htmlEscape(txt);
      e.dataTransfer.setDragImage(escapeElement, 0, 0);
      e.dataTransfer.setData("Text", txt);
    }
    function handleKeyBinding(e) {
      var name = keyNames[e_prop(e, "keyCode")], next = keyMap[options.keyMap].auto, bound, dropShift;
      function handleNext() {
        return next.call ? next.call(null, instance) : next;
      }
      if (name == null || e.altGraphKey) {
        if (next) options.keyMap = handleNext();
        return null;
      }
      if (e_prop(e, "altKey")) name = "Alt-" + name;
      if (e_prop(e, "ctrlKey")) name = "Ctrl-" + name;
      if (e_prop(e, "metaKey")) name = "Cmd-" + name;
      if (e_prop(e, "shiftKey") &&
          (bound = lookupKey("Shift-" + name, options.extraKeys, options.keyMap))) {
        dropShift = true;
      } else {
        bound = lookupKey(name, options.extraKeys, options.keyMap);
      }
      if (typeof bound == "string") {
        if (commands.propertyIsEnumerable(bound)) bound = commands[bound];
        else bound = null;
      }
      if (next && (bound || !isModifierKey(e))) options.keyMap = handleNext();
      if (!bound) return false;
      var prevShift = shiftSelecting;
      try {
        if (options.readOnly) suppressEdits = true;
        if (dropShift) shiftSelecting = null;
        bound(instance);
      } finally {
        shiftSelecting = prevShift;
        suppressEdits = false;
      }
      e_preventDefault(e);
      return true;
    }
    var lastStoppedKey = null;
    function onKeyDown(e) {
      if (!focused) onFocus();
      if (ie && e.keyCode == 27) { e.returnValue = false; }
      if (options.onKeyEvent && options.onKeyEvent(instance, addStop(e))) return;
      var code = e_prop(e, "keyCode");
      // IE does strange things with escape.
      setShift(code == 16 || e_prop(e, "shiftKey"));
      // First give onKeyEvent option a chance to handle this.
      var handled = handleKeyBinding(e);
      if (window.opera) {
        lastStoppedKey = handled ? code : null;
        // Opera has no cut event... we try to at least catch the key combo
        if (!handled && code == 88 && e_prop(e, mac ? "metaKey" : "ctrlKey"))
          replaceSelection("");
      }
    }
    function onKeyPress(e) {
      if (options.onKeyEvent && options.onKeyEvent(instance, addStop(e))) return;
      var keyCode = e_prop(e, "keyCode"), charCode = e_prop(e, "charCode");
      if (window.opera && keyCode == lastStoppedKey) {lastStoppedKey = null; e_preventDefault(e); return;}
      if (window.opera && !e.which && handleKeyBinding(e)) return;
      if (options.electricChars && mode.electricChars && options.smartIndent && !options.readOnly) {
        var ch = String.fromCharCode(charCode == null ? keyCode : charCode);
        if (mode.electricChars.indexOf(ch) > -1)
          setTimeout(operation(function() {indentLine(sel.to.line, "smart");}), 75);
      }
      fastPoll();
    }
    function onKeyUp(e) {
      if (options.onKeyEvent && options.onKeyEvent(instance, addStop(e))) return;
      if (e_prop(e, "keyCode") == 16) shiftSelecting = null;
    }

    function onFocus() {
      if (options.readOnly == "nocursor") return;
      if (!focused) {
        if (options.onFocus) options.onFocus(instance);
        focused = true;
        if (wrapper.className.search(/\bCodeMirror-focused\b/) == -1)
          wrapper.className += " CodeMirror-focused";
        if (!leaveInputAlone) resetInput(true);
      }
      slowPoll();
      restartBlink();
    }
    function onBlur() {
      if (focused) {
        if (options.onBlur) options.onBlur(instance);
        focused = false;
        if (bracketHighlighted)
          operation(function(){
            if (bracketHighlighted) { bracketHighlighted(); bracketHighlighted = null; }
          })();
        wrapper.className = wrapper.className.replace(" CodeMirror-focused", "");
      }
      clearInterval(blinker);
      setTimeout(function() {if (!focused) shiftSelecting = null;}, 150);
    }

    // Replace the range from from to to by the strings in newText.
    // Afterwards, set the selection to selFrom, selTo.
    function updateLines(from, to, newText, selFrom, selTo) {
      if (suppressEdits) return;
      if (history) {
        var old = [];
        doc.iter(from.line, to.line + 1, function(line) { old.push(line.text); });
        history.addChange(from.line, newText.length, old);
        while (history.done.length > options.undoDepth) history.done.shift();
      }
      updateLinesNoUndo(from, to, newText, selFrom, selTo);
    }
    function unredoHelper(from, to, dir) {
      var set = from.pop(), len = set ? set.length : 0, out = [];
      for (var i = dir > 0 ? 0 : len - 1, e = dir > 0 ? len : -1; i != e; i += dir) {
        var change = set[i];
        var replaced = [], end = change.start + change.added;
        doc.iter(change.start, end, function(line) { replaced.push(line.text); });
        out.push({start: change.start, added: change.old.length, old: replaced});
        var pos = clipPos({line: change.start + change.old.length - 1,
                           ch: editEnd(replaced[replaced.length-1], change.old[change.old.length-1])});
        updateLinesNoUndo({line: change.start, ch: 0}, {line: end - 1, ch: getLine(end-1).text.length}, change.old, pos, pos);
      }
      updateInput = true;
      to.push(out);
    }
    function undo() {unredoHelper(history.done, history.undone, -1);}
    function redo() {unredoHelper(history.undone, history.done, 1);}

    function updateLinesNoUndo(from, to, newText, selFrom, selTo) {
      if (suppressEdits) return;
      var recomputeMaxLength = false, maxLineLength = maxLine.length;
      if (!options.lineWrapping)
        doc.iter(from.line, to.line, function(line) {
          if (line.text.length == maxLineLength) {recomputeMaxLength = true; return true;}
        });
      if (from.line != to.line || newText.length > 1) gutterDirty = true;

      var nlines = to.line - from.line, firstLine = getLine(from.line), lastLine = getLine(to.line);
      // First adjust the line structure, taking some care to leave highlighting intact.
      if (from.ch == 0 && to.ch == 0 && newText[newText.length - 1] == "") {
        // This is a whole-line replace. Treated specially to make
        // sure line objects move the way they are supposed to.
        var added = [], prevLine = null;
        if (from.line) {
          prevLine = getLine(from.line - 1);
          prevLine.fixMarkEnds(lastLine);
        } else lastLine.fixMarkStarts();
        for (var i = 0, e = newText.length - 1; i < e; ++i)
          added.push(Line.inheritMarks(newText[i], prevLine));
        if (nlines) doc.remove(from.line, nlines, callbacks);
        if (added.length) doc.insert(from.line, added);
      } else if (firstLine == lastLine) {
        if (newText.length == 1)
          firstLine.replace(from.ch, to.ch, newText[0]);
        else {
          lastLine = firstLine.split(to.ch, newText[newText.length-1]);
          firstLine.replace(from.ch, null, newText[0]);
          firstLine.fixMarkEnds(lastLine);
          var added = [];
          for (var i = 1, e = newText.length - 1; i < e; ++i)
            added.push(Line.inheritMarks(newText[i], firstLine));
          added.push(lastLine);
          doc.insert(from.line + 1, added);
        }
      } else if (newText.length == 1) {
        firstLine.replace(from.ch, null, newText[0]);
        lastLine.replace(null, to.ch, "");
        firstLine.append(lastLine);
        doc.remove(from.line + 1, nlines, callbacks);
      } else {
        var added = [];
        firstLine.replace(from.ch, null, newText[0]);
        lastLine.replace(null, to.ch, newText[newText.length-1]);
        firstLine.fixMarkEnds(lastLine);
        for (var i = 1, e = newText.length - 1; i < e; ++i)
          added.push(Line.inheritMarks(newText[i], firstLine));
        if (nlines > 1) doc.remove(from.line + 1, nlines - 1, callbacks);
        doc.insert(from.line + 1, added);
      }
      if (options.lineWrapping) {
        var perLine = scroller.clientWidth / charWidth() - 3;
        doc.iter(from.line, from.line + newText.length, function(line) {
          if (line.hidden) return;
          var guess = Math.ceil(line.text.length / perLine) || 1;
          if (guess != line.height) updateLineHeight(line, guess);
        });
      } else {
        doc.iter(from.line, i + newText.length, function(line) {
          var l = line.text;
          if (l.length > maxLineLength) {
            maxLine = l; maxLineLength = l.length; maxWidth = null;
            recomputeMaxLength = false;
          }
        });
        if (recomputeMaxLength) {
          maxLineLength = 0; maxLine = ""; maxWidth = null;
          doc.iter(0, doc.size, function(line) {
            var l = line.text;
            if (l.length > maxLineLength) {
              maxLineLength = l.length; maxLine = l;
            }
          });
        }
      }

      // Add these lines to the work array, so that they will be
      // highlighted. Adjust work lines if lines were added/removed.
      var newWork = [], lendiff = newText.length - nlines - 1;
      for (var i = 0, l = work.length; i < l; ++i) {
        var task = work[i];
        if (task < from.line) newWork.push(task);
        else if (task > to.line) newWork.push(task + lendiff);
      }
      var hlEnd = from.line + Math.min(newText.length, 500);
      highlightLines(from.line, hlEnd);
      newWork.push(hlEnd);
      work = newWork;
      startWorker(100);
      // Remember that these lines changed, for updating the display
      changes.push({from: from.line, to: to.line + 1, diff: lendiff});
      var changeObj = {from: from, to: to, text: newText};
      if (textChanged) {
        for (var cur = textChanged; cur.next; cur = cur.next) {}
        cur.next = changeObj;
      } else textChanged = changeObj;

      // Update the selection
      function updateLine(n) {return n <= Math.min(to.line, to.line + lendiff) ? n : n + lendiff;}
      setSelection(selFrom, selTo, updateLine(sel.from.line), updateLine(sel.to.line));

      // Make sure the scroll-size div has the correct height.
      if (scroller.clientHeight)
        code.style.height = (doc.height * textHeight() + 2 * paddingTop()) + "px";
    }

    function replaceRange(code, from, to) {
      from = clipPos(from);
      if (!to) to = from; else to = clipPos(to);
      code = splitLines(code);
      function adjustPos(pos) {
        if (posLess(pos, from)) return pos;
        if (!posLess(to, pos)) return end;
        var line = pos.line + code.length - (to.line - from.line) - 1;
        var ch = pos.ch;
        if (pos.line == to.line)
          ch += code[code.length-1].length - (to.ch - (to.line == from.line ? from.ch : 0));
        return {line: line, ch: ch};
      }
      var end;
      replaceRange1(code, from, to, function(end1) {
        end = end1;
        return {from: adjustPos(sel.from), to: adjustPos(sel.to)};
      });
      return end;
    }
    function replaceSelection(code, collapse) {
      replaceRange1(splitLines(code), sel.from, sel.to, function(end) {
        if (collapse == "end") return {from: end, to: end};
        else if (collapse == "start") return {from: sel.from, to: sel.from};
        else return {from: sel.from, to: end};
      });
    }
    function replaceRange1(code, from, to, computeSel) {
      var endch = code.length == 1 ? code[0].length + from.ch : code[code.length-1].length;
      var newSel = computeSel({line: from.line + code.length - 1, ch: endch});
      updateLines(from, to, code, newSel.from, newSel.to);
    }

    function getRange(from, to) {
      var l1 = from.line, l2 = to.line;
      if (l1 == l2) return getLine(l1).text.slice(from.ch, to.ch);
      var code = [getLine(l1).text.slice(from.ch)];
      doc.iter(l1 + 1, l2, function(line) { code.push(line.text); });
      code.push(getLine(l2).text.slice(0, to.ch));
      return code.join("\n");
    }
    function getSelection() {
      return getRange(sel.from, sel.to);
    }

    var pollingFast = false; // Ensures slowPoll doesn't cancel fastPoll
    function slowPoll() {
      if (pollingFast) return;
      poll.set(options.pollInterval, function() {
        startOperation();
        readInput();
        if (focused) slowPoll();
        endOperation();
      });
    }
    function fastPoll() {
      var missed = false;
      pollingFast = true;
      function p() {
        startOperation();
        var changed = readInput();
        if (!changed && !missed) {missed = true; poll.set(60, p);}
        else {pollingFast = false; slowPoll();}
        endOperation();
      }
      poll.set(20, p);
    }

    // Previnput is a hack to work with IME. If we reset the textarea
    // on every change, that breaks IME. So we look for changes
    // compared to the previous content instead. (Modern browsers have
    // events that indicate IME taking place, but these are not widely
    // supported or compatible enough yet to rely on.)
    var prevInput = "";
    function readInput() {
      if (leaveInputAlone || !focused || hasSelection(input) || options.readOnly) return false;
      var text = input.value;
      if (text == prevInput) return false;
      shiftSelecting = null;
      var same = 0, l = Math.min(prevInput.length, text.length);
      while (same < l && prevInput[same] == text[same]) ++same;
      if (same < prevInput.length)
        sel.from = {line: sel.from.line, ch: sel.from.ch - (prevInput.length - same)};
      else if (overwrite && posEq(sel.from, sel.to))
        sel.to = {line: sel.to.line, ch: Math.min(getLine(sel.to.line).text.length, sel.to.ch + (text.length - same))};
      replaceSelection(text.slice(same), "end");
      prevInput = text;
      return true;
    }
    function resetInput(user) {
      if (!posEq(sel.from, sel.to)) {
        prevInput = "";
        input.value = getSelection();
        selectInput(input);
      } else if (user) prevInput = input.value = "";
    }

    function focusInput() {
      if (options.readOnly != "nocursor") input.focus();
    }

    function scrollEditorIntoView() {
      if (!cursor.getBoundingClientRect) return;
      var rect = cursor.getBoundingClientRect();
      // IE returns bogus coordinates when the instance sits inside of an iframe and the cursor is hidden
      if (ie && rect.top == rect.bottom) return;
      var winH = window.innerHeight || Math.max(document.body.offsetHeight, document.documentElement.offsetHeight);
      if (rect.top < 0 || rect.bottom > winH) cursor.scrollIntoView();
    }
    function scrollCursorIntoView() {
      var cursor = localCoords(sel.inverted ? sel.from : sel.to);
      var x = options.lineWrapping ? Math.min(cursor.x, lineSpace.offsetWidth) : cursor.x;
      return scrollIntoView(x, cursor.y, x, cursor.yBot);
    }
    function scrollIntoView(x1, y1, x2, y2) {
      var pl = paddingLeft(), pt = paddingTop(), lh = textHeight();
      y1 += pt; y2 += pt; x1 += pl; x2 += pl;
      var screen = scroller.clientHeight, screentop = scroller.scrollTop, scrolled = false, result = true;
      if (y1 < screentop) {scroller.scrollTop = Math.max(0, y1 - 2*lh); scrolled = true;}
      else if (y2 > screentop + screen) {scroller.scrollTop = y2 + lh - screen; scrolled = true;}

      var screenw = scroller.clientWidth, screenleft = scroller.scrollLeft;
      var gutterw = options.fixedGutter ? gutter.clientWidth : 0;
      if (x1 < screenleft + gutterw) {
        if (x1 < 50) x1 = 0;
        scroller.scrollLeft = Math.max(0, x1 - 10 - gutterw);
        scrolled = true;
      }
      else if (x2 > screenw + screenleft - 3) {
        scroller.scrollLeft = x2 + 10 - screenw;
        scrolled = true;
        if (x2 > code.clientWidth) result = false;
      }
      if (scrolled && options.onScroll) options.onScroll(instance);
      return result;
    }

    function visibleLines() {
      var lh = textHeight(), top = scroller.scrollTop - paddingTop();
      var from_height = Math.max(0, Math.floor(top / lh));
      var to_height = Math.ceil((top + scroller.clientHeight) / lh);
      return {from: lineAtHeight(doc, from_height),
              to: lineAtHeight(doc, to_height)};
    }
    // Uses a set of changes plus the current scroll position to
    // determine which DOM updates have to be made, and makes the
    // updates.
    function updateDisplay(changes, suppressCallback) {
      if (!scroller.clientWidth) {
        showingFrom = showingTo = displayOffset = 0;
        return;
      }
      // Compute the new visible window
      var visible = visibleLines();
      // Bail out if the visible area is already rendered and nothing changed.
      if (changes !== true && changes.length == 0 && visible.from > showingFrom && visible.to < showingTo) return;
      var from = Math.max(visible.from - 100, 0), to = Math.min(doc.size, visible.to + 100);
      if (showingFrom < from && from - showingFrom < 20) from = showingFrom;
      if (showingTo > to && showingTo - to < 20) to = Math.min(doc.size, showingTo);

      // Create a range of theoretically intact lines, and punch holes
      // in that using the change info.
      var intact = changes === true ? [] :
        computeIntact([{from: showingFrom, to: showingTo, domStart: 0}], changes);
      // Clip off the parts that won't be visible
      var intactLines = 0;
      for (var i = 0; i < intact.length; ++i) {
        var range = intact[i];
        if (range.from < from) {range.domStart += (from - range.from); range.from = from;}
        if (range.to > to) range.to = to;
        if (range.from >= range.to) intact.splice(i--, 1);
        else intactLines += range.to - range.from;
      }
      if (intactLines == to - from) return;
      intact.sort(function(a, b) {return a.domStart - b.domStart;});

      var th = textHeight(), gutterDisplay = gutter.style.display;
      lineDiv.style.display = "none";
      patchDisplay(from, to, intact);
      lineDiv.style.display = gutter.style.display = "";

      // Position the mover div to align with the lines it's supposed
      // to be showing (which will cover the visible display)
      var different = from != showingFrom || to != showingTo || lastSizeC != scroller.clientHeight + th;
      // This is just a bogus formula that detects when the editor is
      // resized or the font size changes.
      if (different) lastSizeC = scroller.clientHeight + th;
      showingFrom = from; showingTo = to;
      displayOffset = heightAtLine(doc, from);
      mover.style.top = (displayOffset * th) + "px";
      if (scroller.clientHeight)
        code.style.height = (doc.height * th + 2 * paddingTop()) + "px";

      // Since this is all rather error prone, it is honoured with the
      // only assertion in the whole file.
      if (lineDiv.childNodes.length != showingTo - showingFrom)
        throw new Error("BAD PATCH! " + JSON.stringify(intact) + " size=" + (showingTo - showingFrom) +
                        " nodes=" + lineDiv.childNodes.length);

      if (options.lineWrapping) {
        maxWidth = scroller.clientWidth;
        var curNode = lineDiv.firstChild, heightChanged = false;
        doc.iter(showingFrom, showingTo, function(line) {
          if (!line.hidden) {
            var height = Math.round(curNode.offsetHeight / th) || 1;
            if (line.height != height) {
              updateLineHeight(line, height);
              gutterDirty = heightChanged = true;
            }
          }
          curNode = curNode.nextSibling;
        });
        if (heightChanged)
          code.style.height = (doc.height * th + 2 * paddingTop()) + "px";
      } else {
        if (maxWidth == null) maxWidth = stringWidth(maxLine);
        if (maxWidth > scroller.clientWidth) {
          lineSpace.style.width = maxWidth + "px";
          // Needed to prevent odd wrapping/hiding of widgets placed in here.
          code.style.width = "";
          code.style.width = scroller.scrollWidth + "px";
        } else {
          lineSpace.style.width = code.style.width = "";
        }
      }
      gutter.style.display = gutterDisplay;
      if (different || gutterDirty) updateGutter();
      updateSelection();
      if (!suppressCallback && options.onUpdate) options.onUpdate(instance);
      return true;
    }

    function computeIntact(intact, changes) {
      for (var i = 0, l = changes.length || 0; i < l; ++i) {
        var change = changes[i], intact2 = [], diff = change.diff || 0;
        for (var j = 0, l2 = intact.length; j < l2; ++j) {
          var range = intact[j];
          if (change.to <= range.from && change.diff)
            intact2.push({from: range.from + diff, to: range.to + diff,
                          domStart: range.domStart});
          else if (change.to <= range.from || change.from >= range.to)
            intact2.push(range);
          else {
            if (change.from > range.from)
              intact2.push({from: range.from, to: change.from, domStart: range.domStart});
            if (change.to < range.to)
              intact2.push({from: change.to + diff, to: range.to + diff,
                            domStart: range.domStart + (change.to - range.from)});
          }
        }
        intact = intact2;
      }
      return intact;
    }

    function patchDisplay(from, to, intact) {
      // The first pass removes the DOM nodes that aren't intact.
      if (!intact.length) lineDiv.innerHTML = "";
      else {
        function killNode(node) {
          var tmp = node.nextSibling;
          node.parentNode.removeChild(node);
          return tmp;
        }
        var domPos = 0, curNode = lineDiv.firstChild, n;
        for (var i = 0; i < intact.length; ++i) {
          var cur = intact[i];
          while (cur.domStart > domPos) {curNode = killNode(curNode); domPos++;}
          for (var j = 0, e = cur.to - cur.from; j < e; ++j) {curNode = curNode.nextSibling; domPos++;}
        }
        while (curNode) curNode = killNode(curNode);
      }
      // This pass fills in the lines that actually changed.
      var nextIntact = intact.shift(), curNode = lineDiv.firstChild, j = from;
      var scratch = targetDocument.createElement("div"), newElt;
      doc.iter(from, to, function(line) {
        if (nextIntact && nextIntact.to == j) nextIntact = intact.shift();
        if (!nextIntact || nextIntact.from > j) {
          if (line.hidden) var html = scratch.innerHTML = "<pre></pre>";
          else {
            var html = '<pre>' + line.getHTML(tabText) + '</pre>';
            // Kludge to make sure the styled element lies behind the selection (by z-index)
            if (line.className)
              html = '<div style="position: relative"><pre class="' + line.className +
              '" style="position: absolute; left: 0; right: 0; top: 0; bottom: 0; z-index: -2">&#160;</pre>' + html + "</div>";
          }
          scratch.innerHTML = html;
          lineDiv.insertBefore(scratch.firstChild, curNode);
        } else {
          curNode = curNode.nextSibling;
        }
        ++j;
      });
    }

    function updateGutter() {
      if (!options.gutter && !options.lineNumbers) return;
      var hText = mover.offsetHeight, hEditor = scroller.clientHeight;
      gutter.style.height = (hText - hEditor < 2 ? hEditor : hText) + "px";
      var html = [], i = showingFrom;
      doc.iter(showingFrom, Math.max(showingTo, showingFrom + 1), function(line) {
        if (line.hidden) {
          html.push("<pre></pre>");
        } else {
          var marker = line.gutterMarker;
          var text = options.lineNumbers ? i + options.firstLineNumber : null;
          if (marker && marker.text)
            text = marker.text.replace("%N%", text != null ? text : "");
          else if (text == null)
            text = "\u00a0";
          html.push((marker && marker.style ? '<pre class="' + marker.style + '">' : "<pre>"), text);
          for (var j = 1; j < line.height; ++j) html.push("<br/>&#160;");
          html.push("</pre>");
        }
        ++i;
      });
      gutter.style.display = "none";
      gutterText.innerHTML = html.join("");
      var minwidth = String(doc.size).length, firstNode = gutterText.firstChild, val = eltText(firstNode), pad = "";
      while (val.length + pad.length < minwidth) pad += "\u00a0";
      if (pad) firstNode.insertBefore(targetDocument.createTextNode(pad), firstNode.firstChild);
      gutter.style.display = "";
      lineSpace.style.marginLeft = gutter.offsetWidth + "px";
      gutterDirty = false;
    }
    function updateSelection() {
      var collapsed = posEq(sel.from, sel.to);
      var fromPos = localCoords(sel.from, true);
      var toPos = collapsed ? fromPos : localCoords(sel.to, true);
      var headPos = sel.inverted ? fromPos : toPos, th = textHeight();
      var wrapOff = eltOffset(wrapper), lineOff = eltOffset(lineDiv);
      inputDiv.style.top = Math.max(0, Math.min(scroller.offsetHeight, headPos.y + lineOff.top - wrapOff.top)) + "px";
      inputDiv.style.left = Math.max(0, Math.min(scroller.offsetWidth, headPos.x + lineOff.left - wrapOff.left)) + "px";
      if (collapsed) {
        cursor.style.top = headPos.y + "px";
        cursor.style.left = (options.lineWrapping ? Math.min(headPos.x, lineSpace.offsetWidth) : headPos.x) + "px";
        cursor.style.display = "";
        selectionDiv.style.display = "none";
      } else {
        var sameLine = fromPos.y == toPos.y, html = "";
        function add(left, top, right, height) {
          html += '<div class="CodeMirror-selected" style="position: absolute; left: ' + left +
            'px; top: ' + top + 'px; right: ' + right + 'px; height: ' + height + 'px"></div>';
        }
        if (sel.from.ch && fromPos.y >= 0) {
          var right = sameLine ? lineSpace.clientWidth - toPos.x : 0;
          add(fromPos.x, fromPos.y, right, th);
        }
        var middleStart = Math.max(0, fromPos.y + (sel.from.ch ? th : 0));
        var middleHeight = Math.min(toPos.y, lineSpace.clientHeight) - middleStart;
        if (middleHeight > 0.2 * th)
          add(0, middleStart, 0, middleHeight);
        if ((!sameLine || !sel.from.ch) && toPos.y < lineSpace.clientHeight - .5 * th)
          add(0, toPos.y, lineSpace.clientWidth - toPos.x, th);
        selectionDiv.innerHTML = html;
        cursor.style.display = "none";
        selectionDiv.style.display = "";
      }
    }

    function setShift(val) {
      if (val) shiftSelecting = shiftSelecting || (sel.inverted ? sel.to : sel.from);
      else shiftSelecting = null;
    }
    function setSelectionUser(from, to) {
      var sh = shiftSelecting && clipPos(shiftSelecting);
      if (sh) {
        if (posLess(sh, from)) from = sh;
        else if (posLess(to, sh)) to = sh;
      }
      setSelection(from, to);
      userSelChange = true;
    }
    // Update the selection. Last two args are only used by
    // updateLines, since they have to be expressed in the line
    // numbers before the update.
    function setSelection(from, to, oldFrom, oldTo) {
      goalColumn = null;
      if (oldFrom == null) {oldFrom = sel.from.line; oldTo = sel.to.line;}
      if (posEq(sel.from, from) && posEq(sel.to, to)) return;
      if (posLess(to, from)) {var tmp = to; to = from; from = tmp;}

      // Skip over hidden lines.
      if (from.line != oldFrom) from = skipHidden(from, oldFrom, sel.from.ch);
      if (to.line != oldTo) to = skipHidden(to, oldTo, sel.to.ch);

      if (posEq(from, to)) sel.inverted = false;
      else if (posEq(from, sel.to)) sel.inverted = false;
      else if (posEq(to, sel.from)) sel.inverted = true;

      sel.from = from; sel.to = to;
      selectionChanged = true;
    }
    function skipHidden(pos, oldLine, oldCh) {
      function getNonHidden(dir) {
        var lNo = pos.line + dir, end = dir == 1 ? doc.size : -1;
        while (lNo != end) {
          var line = getLine(lNo);
          if (!line.hidden) {
            var ch = pos.ch;
            if (ch > oldCh || ch > line.text.length) ch = line.text.length;
            return {line: lNo, ch: ch};
          }
          lNo += dir;
        }
      }
      var line = getLine(pos.line);
      if (!line.hidden) return pos;
      if (pos.line >= oldLine) return getNonHidden(1) || getNonHidden(-1);
      else return getNonHidden(-1) || getNonHidden(1);
    }
    function setCursor(line, ch, user) {
      var pos = clipPos({line: line, ch: ch || 0});
      (user ? setSelectionUser : setSelection)(pos, pos);
    }

    function clipLine(n) {return Math.max(0, Math.min(n, doc.size-1));}
    function clipPos(pos) {
      if (pos.line < 0) return {line: 0, ch: 0};
      if (pos.line >= doc.size) return {line: doc.size-1, ch: getLine(doc.size-1).text.length};
      var ch = pos.ch, linelen = getLine(pos.line).text.length;
      if (ch == null || ch > linelen) return {line: pos.line, ch: linelen};
      else if (ch < 0) return {line: pos.line, ch: 0};
      else return pos;
    }

    function findPosH(dir, unit) {
      var end = sel.inverted ? sel.from : sel.to, line = end.line, ch = end.ch;
      var lineObj = getLine(line);
      function findNextLine() {
        for (var l = line + dir, e = dir < 0 ? -1 : doc.size; l != e; l += dir) {
          var lo = getLine(l);
          if (!lo.hidden) { line = l; lineObj = lo; return true; }
        }
      }
      function moveOnce(boundToLine) {
        if (ch == (dir < 0 ? 0 : lineObj.text.length)) {
          if (!boundToLine && findNextLine()) ch = dir < 0 ? lineObj.text.length : 0;
          else return false;
        } else ch += dir;
        return true;
      }
      if (unit == "char") moveOnce();
      else if (unit == "column") moveOnce(true);
      else if (unit == "word") {
        var sawWord = false;
        for (;;) {
          if (dir < 0) if (!moveOnce()) break;
          if (isWordChar(lineObj.text.charAt(ch))) sawWord = true;
          else if (sawWord) {if (dir < 0) {dir = 1; moveOnce();} break;}
          if (dir > 0) if (!moveOnce()) break;
        }
      }
      return {line: line, ch: ch};
    }
    function moveH(dir, unit) {
      var pos = dir < 0 ? sel.from : sel.to;
      if (shiftSelecting || posEq(sel.from, sel.to)) pos = findPosH(dir, unit);
      setCursor(pos.line, pos.ch, true);
    }
    function deleteH(dir, unit) {
      if (!posEq(sel.from, sel.to)) replaceRange("", sel.from, sel.to);
      else if (dir < 0) replaceRange("", findPosH(dir, unit), sel.to);
      else replaceRange("", sel.from, findPosH(dir, unit));
      userSelChange = true;
    }
    var goalColumn = null;
    function moveV(dir, unit) {
      var dist = 0, pos = localCoords(sel.inverted ? sel.from : sel.to, true);
      if (goalColumn != null) pos.x = goalColumn;
      if (unit == "page") dist = Math.min(scroller.clientHeight, window.innerHeight || document.documentElement.clientHeight);
      else if (unit == "line") dist = textHeight();
      var target = coordsChar(pos.x, pos.y + dist * dir + 2);
      setCursor(target.line, target.ch, true);
      goalColumn = pos.x;
    }

    function selectWordAt(pos) {
      var line = getLine(pos.line).text;
      var start = pos.ch, end = pos.ch;
      while (start > 0 && isWordChar(line.charAt(start - 1))) --start;
      while (end < line.length && isWordChar(line.charAt(end))) ++end;
      setSelectionUser({line: pos.line, ch: start}, {line: pos.line, ch: end});
    }
    function selectLine(line) {
      setSelectionUser({line: line, ch: 0}, {line: line, ch: getLine(line).text.length});
    }
    function indentSelected(mode) {
      if (posEq(sel.from, sel.to)) return indentLine(sel.from.line, mode);
      var e = sel.to.line - (sel.to.ch ? 0 : 1);
      for (var i = sel.from.line; i <= e; ++i) indentLine(i, mode);
    }

    function indentLine(n, how) {
      if (!how) how = "add";
      if (how == "smart") {
        if (!mode.indent) how = "prev";
        else var state = getStateBefore(n);
      }

      var line = getLine(n), curSpace = line.indentation(options.tabSize),
          curSpaceString = line.text.match(/^\s*/)[0], indentation;
      if (how == "prev") {
        if (n) indentation = getLine(n-1).indentation(options.tabSize);
        else indentation = 0;
      }
      else if (how == "smart") indentation = mode.indent(state, line.text.slice(curSpaceString.length), line.text);
      else if (how == "add") indentation = curSpace + options.indentUnit;
      else if (how == "subtract") indentation = curSpace - options.indentUnit;
      indentation = Math.max(0, indentation);
      var diff = indentation - curSpace;

      if (!diff) {
        if (sel.from.line != n && sel.to.line != n) return;
        var indentString = curSpaceString;
      }
      else {
        var indentString = "", pos = 0;
        if (options.indentWithTabs)
          for (var i = Math.floor(indentation / options.tabSize); i; --i) {pos += options.tabSize; indentString += "\t";}
        while (pos < indentation) {++pos; indentString += " ";}
      }

      replaceRange(indentString, {line: n, ch: 0}, {line: n, ch: curSpaceString.length});
    }

    function loadMode() {
      mode = CodeMirror.getMode(options, options.mode);
      doc.iter(0, doc.size, function(line) { line.stateAfter = null; });
      work = [0];
      startWorker();
    }
    function gutterChanged() {
      var visible = options.gutter || options.lineNumbers;
      gutter.style.display = visible ? "" : "none";
      if (visible) gutterDirty = true;
      else lineDiv.parentNode.style.marginLeft = 0;
    }
    function wrappingChanged(from, to) {
      if (options.lineWrapping) {
        wrapper.className += " CodeMirror-wrap";
        var perLine = scroller.clientWidth / charWidth() - 3;
        doc.iter(0, doc.size, function(line) {
          if (line.hidden) return;
          var guess = Math.ceil(line.text.length / perLine) || 1;
          if (guess != 1) updateLineHeight(line, guess);
        });
        lineSpace.style.width = code.style.width = "";
      } else {
        wrapper.className = wrapper.className.replace(" CodeMirror-wrap", "");
        maxWidth = null; maxLine = "";
        doc.iter(0, doc.size, function(line) {
          if (line.height != 1 && !line.hidden) updateLineHeight(line, 1);
          if (line.text.length > maxLine.length) maxLine = line.text;
        });
      }
      changes.push({from: 0, to: doc.size});
    }
    function computeTabText() {
      for (var str = '<span class="cm-tab">', i = 0; i < options.tabSize; ++i) str += " ";
      return str + "</span>";
    }
    function tabsChanged() {
      tabText = computeTabText();
      updateDisplay(true);
    }
    function themeChanged() {
      scroller.className = scroller.className.replace(/\s*cm-s-\w+/g, "") +
        options.theme.replace(/(^|\s)\s*/g, " cm-s-");
    }

    function TextMarker() { this.set = []; }
    TextMarker.prototype.clear = operation(function() {
      var min = Infinity, max = -Infinity;
      for (var i = 0, e = this.set.length; i < e; ++i) {
        var line = this.set[i], mk = line.marked;
        if (!mk || !line.parent) continue;
        var lineN = lineNo(line);
        min = Math.min(min, lineN); max = Math.max(max, lineN);
        for (var j = 0; j < mk.length; ++j)
          if (mk[j].set == this.set) mk.splice(j--, 1);
      }
      if (min != Infinity)
        changes.push({from: min, to: max + 1});
    });
    TextMarker.prototype.find = function() {
      var from, to;
      for (var i = 0, e = this.set.length; i < e; ++i) {
        var line = this.set[i], mk = line.marked;
        for (var j = 0; j < mk.length; ++j) {
          var mark = mk[j];
          if (mark.set == this.set) {
            if (mark.from != null || mark.to != null) {
              var found = lineNo(line);
              if (found != null) {
                if (mark.from != null) from = {line: found, ch: mark.from};
                if (mark.to != null) to = {line: found, ch: mark.to};
              }
            }
          }
        }
      }
      return {from: from, to: to};
    };

    function markText(from, to, className) {
      from = clipPos(from); to = clipPos(to);
      var tm = new TextMarker();
      function add(line, from, to, className) {
        getLine(line).addMark(new MarkedText(from, to, className, tm.set));
      }
      if (from.line == to.line) add(from.line, from.ch, to.ch, className);
      else {
        add(from.line, from.ch, null, className);
        for (var i = from.line + 1, e = to.line; i < e; ++i)
          add(i, null, null, className);
        add(to.line, null, to.ch, className);
      }
      changes.push({from: from.line, to: to.line + 1});
      return tm;
    }

    function setBookmark(pos) {
      pos = clipPos(pos);
      var bm = new Bookmark(pos.ch);
      getLine(pos.line).addMark(bm);
      return bm;
    }

    function addGutterMarker(line, text, className) {
      if (typeof line == "number") line = getLine(clipLine(line));
      line.gutterMarker = {text: text, style: className};
      gutterDirty = true;
      return line;
    }
    function removeGutterMarker(line) {
      if (typeof line == "number") line = getLine(clipLine(line));
      line.gutterMarker = null;
      gutterDirty = true;
    }

    function changeLine(handle, op) {
      var no = handle, line = handle;
      if (typeof handle == "number") line = getLine(clipLine(handle));
      else no = lineNo(handle);
      if (no == null) return null;
      if (op(line, no)) changes.push({from: no, to: no + 1});
      else return null;
      return line;
    }
    function setLineClass(handle, className) {
      return changeLine(handle, function(line) {
        if (line.className != className) {
          line.className = className;
          return true;
        }
      });
    }
    function setLineHidden(handle, hidden) {
      return changeLine(handle, function(line, no) {
        if (line.hidden != hidden) {
          line.hidden = hidden;
          updateLineHeight(line, hidden ? 0 : 1);
          var fline = sel.from.line, tline = sel.to.line;
          if (hidden && (fline == no || tline == no)) {
            var from = fline == no ? skipHidden({line: fline, ch: 0}, fline, 0) : sel.from;
            var to = tline == no ? skipHidden({line: tline, ch: 0}, tline, 0) : sel.to;
            setSelection(from, to);
          }
          return (gutterDirty = true);
        }
      });
    }

    function lineInfo(line) {
      if (typeof line == "number") {
        if (!isLine(line)) return null;
        var n = line;
        line = getLine(line);
        if (!line) return null;
      }
      else {
        var n = lineNo(line);
        if (n == null) return null;
      }
      var marker = line.gutterMarker;
      return {line: n, handle: line, text: line.text, markerText: marker && marker.text,
              markerClass: marker && marker.style, lineClass: line.className};
    }

    function stringWidth(str) {
      measure.innerHTML = "<pre><span>x</span></pre>";
      measure.firstChild.firstChild.firstChild.nodeValue = str;
      return measure.firstChild.firstChild.offsetWidth || 10;
    }
    // These are used to go from pixel positions to character
    // positions, taking varying character widths into account.
    function charFromX(line, x) {
      if (x <= 0) return 0;
      var lineObj = getLine(line), text = lineObj.text;
      function getX(len) {
        measure.innerHTML = "<pre><span>" + lineObj.getHTML(tabText, len) + "</span></pre>";
        return measure.firstChild.firstChild.offsetWidth;
      }
      var from = 0, fromX = 0, to = text.length, toX;
      // Guess a suitable upper bound for our search.
      var estimated = Math.min(to, Math.ceil(x / charWidth()));
      for (;;) {
        var estX = getX(estimated);
        if (estX <= x && estimated < to) estimated = Math.min(to, Math.ceil(estimated * 1.2));
        else {toX = estX; to = estimated; break;}
      }
      if (x > toX) return to;
      // Try to guess a suitable lower bound as well.
      estimated = Math.floor(to * 0.8); estX = getX(estimated);
      if (estX < x) {from = estimated; fromX = estX;}
      // Do a binary search between these bounds.
      for (;;) {
        if (to - from <= 1) return (toX - x > x - fromX) ? from : to;
        var middle = Math.ceil((from + to) / 2), middleX = getX(middle);
        if (middleX > x) {to = middle; toX = middleX;}
        else {from = middle; fromX = middleX;}
      }
    }

    var tempId = Math.floor(Math.random() * 0xffffff).toString(16);
    function measureLine(line, ch) {
      if (ch == 0) return {top: 0, left: 0};
      var extra = "";
      // Include extra text at the end to make sure the measured line is wrapped in the right way.
      if (options.lineWrapping) {
        var end = line.text.indexOf(" ", ch + 2);
        extra = htmlEscape(line.text.slice(ch + 1, end < 0 ? line.text.length : end + (ie ? 5 : 0)));
      }
      measure.innerHTML = "<pre>" + line.getHTML(tabText, ch) +
        '<span id="CodeMirror-temp-' + tempId + '">' + htmlEscape(line.text.charAt(ch) || " ") + "</span>" +
        extra + "</pre>";
      var elt = document.getElementById("CodeMirror-temp-" + tempId);
      var top = elt.offsetTop, left = elt.offsetLeft;
      // Older IEs report zero offsets for spans directly after a wrap
      if (ie && top == 0 && left == 0) {
        var backup = document.createElement("span");
        backup.innerHTML = "x";
        elt.parentNode.insertBefore(backup, elt.nextSibling);
        top = backup.offsetTop;
      }
      return {top: top, left: left};
    }
    function localCoords(pos, inLineWrap) {
      var x, lh = textHeight(), y = lh * (heightAtLine(doc, pos.line) - (inLineWrap ? displayOffset : 0));
      if (pos.ch == 0) x = 0;
      else {
        var sp = measureLine(getLine(pos.line), pos.ch);
        x = sp.left;
        if (options.lineWrapping) y += Math.max(0, sp.top);
      }
      return {x: x, y: y, yBot: y + lh};
    }
    // Coords must be lineSpace-local
    function coordsChar(x, y) {
      if (y < 0) y = 0;
      var th = textHeight(), cw = charWidth(), heightPos = displayOffset + Math.floor(y / th);
      var lineNo = lineAtHeight(doc, heightPos);
      if (lineNo >= doc.size) return {line: doc.size - 1, ch: getLine(doc.size - 1).text.length};
      var lineObj = getLine(lineNo), text = lineObj.text;
      var tw = options.lineWrapping, innerOff = tw ? heightPos - heightAtLine(doc, lineNo) : 0;
      if (x <= 0 && innerOff == 0) return {line: lineNo, ch: 0};
      function getX(len) {
        var sp = measureLine(lineObj, len);
        if (tw) {
          var off = Math.round(sp.top / th);
          return Math.max(0, sp.left + (off - innerOff) * scroller.clientWidth);
        }
        return sp.left;
      }
      var from = 0, fromX = 0, to = text.length, toX;
      // Guess a suitable upper bound for our search.
      var estimated = Math.min(to, Math.ceil((x + innerOff * scroller.clientWidth * .9) / cw));
      for (;;) {
        var estX = getX(estimated);
        if (estX <= x && estimated < to) estimated = Math.min(to, Math.ceil(estimated * 1.2));
        else {toX = estX; to = estimated; break;}
      }
      if (x > toX) return {line: lineNo, ch: to};
      // Try to guess a suitable lower bound as well.
      estimated = Math.floor(to * 0.8); estX = getX(estimated);
      if (estX < x) {from = estimated; fromX = estX;}
      // Do a binary search between these bounds.
      for (;;) {
        if (to - from <= 1) return {line: lineNo, ch: (toX - x > x - fromX) ? from : to};
        var middle = Math.ceil((from + to) / 2), middleX = getX(middle);
        if (middleX > x) {to = middle; toX = middleX;}
        else {from = middle; fromX = middleX;}
      }
    }
    function pageCoords(pos) {
      var local = localCoords(pos, true), off = eltOffset(lineSpace);
      return {x: off.left + local.x, y: off.top + local.y, yBot: off.top + local.yBot};
    }

    var cachedHeight, cachedHeightFor, measureText;
    function textHeight() {
      if (measureText == null) {
        measureText = "<pre>";
        for (var i = 0; i < 49; ++i) measureText += "x<br/>";
        measureText += "x</pre>";
      }
      var offsetHeight = lineDiv.clientHeight;
      if (offsetHeight == cachedHeightFor) return cachedHeight;
      cachedHeightFor = offsetHeight;
      measure.innerHTML = measureText;
      cachedHeight = measure.firstChild.offsetHeight / 50 || 1;
      measure.innerHTML = "";
      return cachedHeight;
    }
    var cachedWidth, cachedWidthFor = 0;
    function charWidth() {
      if (scroller.clientWidth == cachedWidthFor) return cachedWidth;
      cachedWidthFor = scroller.clientWidth;
      return (cachedWidth = stringWidth("x"));
    }
    function paddingTop() {return lineSpace.offsetTop;}
    function paddingLeft() {return lineSpace.offsetLeft;}

    function posFromMouse(e, liberal) {
      var offW = eltOffset(scroller, true), x, y;
      // Fails unpredictably on IE[67] when mouse is dragged around quickly.
      try { x = e.clientX; y = e.clientY; } catch (e) { return null; }
      // This is a mess of a heuristic to try and determine whether a
      // scroll-bar was clicked or not, and to return null if one was
      // (and !liberal).
      if (!liberal && (x - offW.left > scroller.clientWidth || y - offW.top > scroller.clientHeight))
        return null;
      var offL = eltOffset(lineSpace, true);
      return coordsChar(x - offL.left, y - offL.top);
    }
    function onContextMenu(e) {
      var pos = posFromMouse(e);
      if (!pos || window.opera) return; // Opera is difficult.
      if (posEq(sel.from, sel.to) || posLess(pos, sel.from) || !posLess(pos, sel.to))
        operation(setCursor)(pos.line, pos.ch);

      var oldCSS = input.style.cssText;
      inputDiv.style.position = "absolute";
      input.style.cssText = "position: fixed; width: 30px; height: 30px; top: " + (e.clientY - 5) +
        "px; left: " + (e.clientX - 5) + "px; z-index: 1000; background: white; " +
        "border-width: 0; outline: none; overflow: hidden; opacity: .05; filter: alpha(opacity=5);";
      leaveInputAlone = true;
      var val = input.value = getSelection();
      focusInput();
      selectInput(input);
      function rehide() {
        var newVal = splitLines(input.value).join("\n");
        if (newVal != val) operation(replaceSelection)(newVal, "end");
        inputDiv.style.position = "relative";
        input.style.cssText = oldCSS;
        leaveInputAlone = false;
        resetInput(true);
        slowPoll();
      }

      if (gecko) {
        e_stop(e);
        var mouseup = connect(window, "mouseup", function() {
          mouseup();
          setTimeout(rehide, 20);
        }, true);
      }
      else {
        setTimeout(rehide, 50);
      }
    }

    // Cursor-blinking
    function restartBlink() {
      clearInterval(blinker);
      var on = true;
      cursor.style.visibility = "";
      blinker = setInterval(function() {
        cursor.style.visibility = (on = !on) ? "" : "hidden";
      }, 650);
    }

    var matching = {"(": ")>", ")": "(<", "[": "]>", "]": "[<", "{": "}>", "}": "{<"};
    function matchBrackets(autoclear) {
      var head = sel.inverted ? sel.from : sel.to, line = getLine(head.line), pos = head.ch - 1;
      var match = (pos >= 0 && matching[line.text.charAt(pos)]) || matching[line.text.charAt(++pos)];
      if (!match) return;
      var ch = match.charAt(0), forward = match.charAt(1) == ">", d = forward ? 1 : -1, st = line.styles;
      for (var off = pos + 1, i = 0, e = st.length; i < e; i+=2)
        if ((off -= st[i].length) <= 0) {var style = st[i+1]; break;}

      var stack = [line.text.charAt(pos)], re = /[(){}[\]]/;
      function scan(line, from, to) {
        if (!line.text) return;
        var st = line.styles, pos = forward ? 0 : line.text.length - 1, cur;
        for (var i = forward ? 0 : st.length - 2, e = forward ? st.length : -2; i != e; i += 2*d) {
          var text = st[i];
          if (st[i+1] != null && st[i+1] != style) {pos += d * text.length; continue;}
          for (var j = forward ? 0 : text.length - 1, te = forward ? text.length : -1; j != te; j += d, pos+=d) {
            if (pos >= from && pos < to && re.test(cur = text.charAt(j))) {
              var match = matching[cur];
              if (match.charAt(1) == ">" == forward) stack.push(cur);
              else if (stack.pop() != match.charAt(0)) return {pos: pos, match: false};
              else if (!stack.length) return {pos: pos, match: true};
            }
          }
        }
      }
      for (var i = head.line, e = forward ? Math.min(i + 100, doc.size) : Math.max(-1, i - 100); i != e; i+=d) {
        var line = getLine(i), first = i == head.line;
        var found = scan(line, first && forward ? pos + 1 : 0, first && !forward ? pos : line.text.length);
        if (found) break;
      }
      if (!found) found = {pos: null, match: false};
      var style = found.match ? "CodeMirror-matchingbracket" : "CodeMirror-nonmatchingbracket";
      var one = markText({line: head.line, ch: pos}, {line: head.line, ch: pos+1}, style),
          two = found.pos != null && markText({line: i, ch: found.pos}, {line: i, ch: found.pos + 1}, style);
      var clear = operation(function(){one.clear(); two && two.clear();});
      if (autoclear) setTimeout(clear, 800);
      else bracketHighlighted = clear;
    }

    // Finds the line to start with when starting a parse. Tries to
    // find a line with a stateAfter, so that it can start with a
    // valid state. If that fails, it returns the line with the
    // smallest indentation, which tends to need the least context to
    // parse correctly.
    function findStartLine(n) {
      var minindent, minline;
      for (var search = n, lim = n - 40; search > lim; --search) {
        if (search == 0) return 0;
        var line = getLine(search-1);
        if (line.stateAfter) return search;
        var indented = line.indentation(options.tabSize);
        if (minline == null || minindent > indented) {
          minline = search - 1;
          minindent = indented;
        }
      }
      return minline;
    }
    function getStateBefore(n) {
      var start = findStartLine(n), state = start && getLine(start-1).stateAfter;
      if (!state) state = startState(mode);
      else state = copyState(mode, state);
      doc.iter(start, n, function(line) {
        line.highlight(mode, state, options.tabSize);
        line.stateAfter = copyState(mode, state);
      });
      if (start < n) changes.push({from: start, to: n});
      if (n < doc.size && !getLine(n).stateAfter) work.push(n);
      return state;
    }
    function highlightLines(start, end) {
      var state = getStateBefore(start);
      doc.iter(start, end, function(line) {
        line.highlight(mode, state, options.tabSize);
        line.stateAfter = copyState(mode, state);
      });
    }
    function highlightWorker() {
      var end = +new Date + options.workTime;
      var foundWork = work.length;
      while (work.length) {
        if (!getLine(showingFrom).stateAfter) var task = showingFrom;
        else var task = work.pop();
        if (task >= doc.size) continue;
        var start = findStartLine(task), state = start && getLine(start-1).stateAfter;
        if (state) state = copyState(mode, state);
        else state = startState(mode);

        var unchanged = 0, compare = mode.compareStates, realChange = false,
            i = start, bail = false;
        doc.iter(i, doc.size, function(line) {
          var hadState = line.stateAfter;
          if (+new Date > end) {
            work.push(i);
            startWorker(options.workDelay);
            if (realChange) changes.push({from: task, to: i + 1});
            return (bail = true);
          }
          var changed = line.highlight(mode, state, options.tabSize);
          if (changed) realChange = true;
          line.stateAfter = copyState(mode, state);
          if (compare) {
            if (hadState && compare(hadState, state)) return true;
          } else {
            if (changed !== false || !hadState) unchanged = 0;
            else if (++unchanged > 3 && (!mode.indent || mode.indent(hadState, "") == mode.indent(state, "")))
              return true;
          }
          ++i;
        });
        if (bail) return;
        if (realChange) changes.push({from: task, to: i + 1});
      }
      if (foundWork && options.onHighlightComplete)
        options.onHighlightComplete(instance);
    }
    function startWorker(time) {
      if (!work.length) return;
      highlight.set(time, operation(highlightWorker));
    }

    // Operations are used to wrap changes in such a way that each
    // change won't have to update the cursor and display (which would
    // be awkward, slow, and error-prone), but instead updates are
    // batched and then all combined and executed at once.
    function startOperation() {
      updateInput = userSelChange = textChanged = null;
      changes = []; selectionChanged = false; callbacks = [];
    }
    function endOperation() {
      var reScroll = false, updated;
      if (selectionChanged) reScroll = !scrollCursorIntoView();
      if (changes.length) updated = updateDisplay(changes, true);
      else {
        if (selectionChanged) updateSelection();
        if (gutterDirty) updateGutter();
      }
      if (reScroll) scrollCursorIntoView();
      if (selectionChanged) {scrollEditorIntoView(); restartBlink();}

      if (focused && !leaveInputAlone &&
          (updateInput === true || (updateInput !== false && selectionChanged)))
        resetInput(userSelChange);

      if (selectionChanged && options.matchBrackets)
        setTimeout(operation(function() {
          if (bracketHighlighted) {bracketHighlighted(); bracketHighlighted = null;}
          if (posEq(sel.from, sel.to)) matchBrackets(false);
        }), 20);
      var tc = textChanged, cbs = callbacks; // these can be reset by callbacks
      if (selectionChanged && options.onCursorActivity)
        options.onCursorActivity(instance);
      if (tc && options.onChange && instance)
        options.onChange(instance, tc);
      for (var i = 0; i < cbs.length; ++i) cbs[i](instance);
      if (updated && options.onUpdate) options.onUpdate(instance);
    }
    var nestedOperation = 0;
    function operation(f) {
      return function() {
        if (!nestedOperation++) startOperation();
        try {var result = f.apply(this, arguments);}
        finally {if (!--nestedOperation) endOperation();}
        return result;
      };
    }

    for (var ext in extensions)
      if (extensions.propertyIsEnumerable(ext) &&
          !instance.propertyIsEnumerable(ext))
        instance[ext] = extensions[ext];
    return instance;
  } // (end of function CodeMirror)

  // The default configuration options.
  CodeMirror.defaults = {
    value: "",
    mode: null,
    theme: "default",
    indentUnit: 2,
    indentWithTabs: false,
    smartIndent: true,
    tabSize: 4,
    keyMap: "default",
    extraKeys: null,
    electricChars: true,
    onKeyEvent: null,
    lineWrapping: false,
    lineNumbers: false,
    gutter: false,
    fixedGutter: false,
    firstLineNumber: 1,
    readOnly: false,
    onChange: null,
    onCursorActivity: null,
    onGutterClick: null,
    onHighlightComplete: null,
    onUpdate: null,
    onFocus: null, onBlur: null, onScroll: null,
    matchBrackets: false,
    workTime: 100,
    workDelay: 200,
    pollInterval: 100,
    undoDepth: 40,
    tabindex: null,
    document: window.document
  };

  var ios = /AppleWebKit/.test(navigator.userAgent) && /Mobile\/\w+/.test(navigator.userAgent);
  var mac = ios || /Mac/.test(navigator.platform);
  var win = /Win/.test(navigator.platform);

  // Known modes, by name and by MIME
  var modes = {}, mimeModes = {};
  CodeMirror.defineMode = function(name, mode) {
    if (!CodeMirror.defaults.mode && name != "null") CodeMirror.defaults.mode = name;
    modes[name] = mode;
  };
  CodeMirror.defineMIME = function(mime, spec) {
    mimeModes[mime] = spec;
  };
  CodeMirror.getMode = function(options, spec) {
    if (typeof spec == "string" && mimeModes.hasOwnProperty(spec))
      spec = mimeModes[spec];
    if (typeof spec == "string")
      var mname = spec, config = {};
    else if (spec != null)
      var mname = spec.name, config = spec;
    var mfactory = modes[mname];
    if (!mfactory) {
      if (window.console) console.warn("No mode " + mname + " found, falling back to plain text.");
      return CodeMirror.getMode(options, "text/plain");
    }
    return mfactory(options, config || {});
  };
  CodeMirror.listModes = function() {
    var list = [];
    for (var m in modes)
      if (modes.propertyIsEnumerable(m)) list.push(m);
    return list;
  };
  CodeMirror.listMIMEs = function() {
    var list = [];
    for (var m in mimeModes)
      if (mimeModes.propertyIsEnumerable(m)) list.push({mime: m, mode: mimeModes[m]});
    return list;
  };

  var extensions = CodeMirror.extensions = {};
  CodeMirror.defineExtension = function(name, func) {
    extensions[name] = func;
  };

  var commands = CodeMirror.commands = {
    selectAll: function(cm) {cm.setSelection({line: 0, ch: 0}, {line: cm.lineCount() - 1});},
    killLine: function(cm) {
      var from = cm.getCursor(true), to = cm.getCursor(false), sel = !posEq(from, to);
      if (!sel && cm.getLine(from.line).length == from.ch) cm.replaceRange("", from, {line: from.line + 1, ch: 0});
      else cm.replaceRange("", from, sel ? to : {line: from.line});
    },
    deleteLine: function(cm) {var l = cm.getCursor().line; cm.replaceRange("", {line: l, ch: 0}, {line: l});},
    undo: function(cm) {cm.undo();},
    redo: function(cm) {cm.redo();},
    goDocStart: function(cm) {cm.setCursor(0, 0, true);},
    goDocEnd: function(cm) {cm.setSelection({line: cm.lineCount() - 1}, null, true);},
    goLineStart: function(cm) {cm.setCursor(cm.getCursor().line, 0, true);},
    goLineStartSmart: function(cm) {
      var cur = cm.getCursor();
      var text = cm.getLine(cur.line), firstNonWS = Math.max(0, text.search(/\S/));
      cm.setCursor(cur.line, cur.ch <= firstNonWS && cur.ch ? 0 : firstNonWS, true);
    },
    goLineEnd: function(cm) {cm.setSelection({line: cm.getCursor().line}, null, true);},
    goLineUp: function(cm) {cm.moveV(-1, "line");},
    goLineDown: function(cm) {cm.moveV(1, "line");},
    goPageUp: function(cm) {cm.moveV(-1, "page");},
    goPageDown: function(cm) {cm.moveV(1, "page");},
    goCharLeft: function(cm) {cm.moveH(-1, "char");},
    goCharRight: function(cm) {cm.moveH(1, "char");},
    goColumnLeft: function(cm) {cm.moveH(-1, "column");},
    goColumnRight: function(cm) {cm.moveH(1, "column");},
    goWordLeft: function(cm) {cm.moveH(-1, "word");},
    goWordRight: function(cm) {cm.moveH(1, "word");},
    delCharLeft: function(cm) {cm.deleteH(-1, "char");},
    delCharRight: function(cm) {cm.deleteH(1, "char");},
    delWordLeft: function(cm) {cm.deleteH(-1, "word");},
    delWordRight: function(cm) {cm.deleteH(1, "word");},
    indentAuto: function(cm) {cm.indentSelection("smart");},
    indentMore: function(cm) {cm.indentSelection("add");},
    indentLess: function(cm) {cm.indentSelection("subtract");},
    insertTab: function(cm) {cm.replaceSelection("\t", "end");},
    transposeChars: function(cm) {
      var cur = cm.getCursor(), line = cm.getLine(cur.line);
      if (cur.ch > 0 && cur.ch < line.length - 1)
        cm.replaceRange(line.charAt(cur.ch) + line.charAt(cur.ch - 1),
                        {line: cur.line, ch: cur.ch - 1}, {line: cur.line, ch: cur.ch + 1});
    },
    newlineAndIndent: function(cm) {
      cm.replaceSelection("\n", "end");
      cm.indentLine(cm.getCursor().line);
    },
    toggleOverwrite: function(cm) {cm.toggleOverwrite();}
  };

  var keyMap = CodeMirror.keyMap = {};
  keyMap.basic = {
    "Left": "goCharLeft", "Right": "goCharRight", "Up": "goLineUp", "Down": "goLineDown",
    "End": "goLineEnd", "Home": "goLineStartSmart", "PageUp": "goPageUp", "PageDown": "goPageDown",
    "Delete": "delCharRight", "Backspace": "delCharLeft", "Tab": "indentMore", "Shift-Tab": "indentLess",
    "Enter": "newlineAndIndent", "Insert": "toggleOverwrite"
  };
  // Note that the save and find-related commands aren't defined by
  // default. Unknown commands are simply ignored.
  keyMap.pcDefault = {
    "Ctrl-A": "selectAll", "Ctrl-D": "deleteLine", "Ctrl-Z": "undo", "Shift-Ctrl-Z": "redo", "Ctrl-Y": "redo",
    "Ctrl-Home": "goDocStart", "Alt-Up": "goDocStart", "Ctrl-End": "goDocEnd", "Ctrl-Down": "goDocEnd",
    "Ctrl-Left": "goWordLeft", "Ctrl-Right": "goWordRight", "Alt-Left": "goLineStart", "Alt-Right": "goLineEnd",
    "Ctrl-Backspace": "delWordLeft", "Ctrl-Delete": "delWordRight", "Ctrl-S": "save", "Ctrl-F": "find",
    "Ctrl-G": "findNext", "Shift-Ctrl-G": "findPrev", "Shift-Ctrl-F": "replace", "Shift-Ctrl-R": "replaceAll",
    fallthrough: "basic"
  };
  keyMap.macDefault = {
    "Cmd-A": "selectAll", "Cmd-D": "deleteLine", "Cmd-Z": "undo", "Shift-Cmd-Z": "redo", "Cmd-Y": "redo",
    "Cmd-Up": "goDocStart", "Cmd-End": "goDocEnd", "Cmd-Down": "goDocEnd", "Alt-Left": "goWordLeft",
    "Alt-Right": "goWordRight", "Cmd-Left": "goLineStart", "Cmd-Right": "goLineEnd", "Alt-Backspace": "delWordLeft",
    "Ctrl-Alt-Backspace": "delWordRight", "Alt-Delete": "delWordRight", "Cmd-S": "save", "Cmd-F": "find",
    "Cmd-G": "findNext", "Shift-Cmd-G": "findPrev", "Cmd-Alt-F": "replace", "Shift-Cmd-Alt-F": "replaceAll",
    fallthrough: ["basic", "emacsy"]
  };
  keyMap["default"] = mac ? keyMap.macDefault : keyMap.pcDefault;
  keyMap.emacsy = {
    "Ctrl-F": "goCharRight", "Ctrl-B": "goCharLeft", "Ctrl-P": "goLineUp", "Ctrl-N": "goLineDown",
    "Alt-F": "goWordRight", "Alt-B": "goWordLeft", "Ctrl-A": "goLineStart", "Ctrl-E": "goLineEnd",
    "Ctrl-V": "goPageUp", "Shift-Ctrl-V": "goPageDown", "Ctrl-D": "delCharRight", "Ctrl-H": "delCharLeft",
    "Alt-D": "delWordRight", "Alt-Backspace": "delWordLeft", "Ctrl-K": "killLine", "Ctrl-T": "transposeChars"
  };

  function lookupKey(name, extraMap, map) {
    function lookup(name, map, ft) {
      var found = map[name];
      if (found != null) return found;
      if (ft == null) ft = map.fallthrough;
      if (ft == null) return map.catchall;
      if (typeof ft == "string") return lookup(name, keyMap[ft]);
      for (var i = 0, e = ft.length; i < e; ++i) {
        found = lookup(name, keyMap[ft[i]]);
        if (found != null) return found;
      }
      return null;
    }
    return extraMap ? lookup(name, extraMap, map) : lookup(name, keyMap[map]);
  }
  function isModifierKey(event) {
    var name = keyNames[e_prop(event, "keyCode")];
    return name == "Ctrl" || name == "Alt" || name == "Shift" || name == "Mod";
  }

  CodeMirror.fromTextArea = function(textarea, options) {
    if (!options) options = {};
    options.value = textarea.value;
    if (!options.tabindex && textarea.tabindex)
      options.tabindex = textarea.tabindex;

    function save() {textarea.value = instance.getValue();}
    if (textarea.form) {
      // Deplorable hack to make the submit method do the right thing.
      var rmSubmit = connect(textarea.form, "submit", save, true);
      if (typeof textarea.form.submit == "function") {
        var realSubmit = textarea.form.submit;
        function wrappedSubmit() {
          save();
          textarea.form.submit = realSubmit;
          textarea.form.submit();
          textarea.form.submit = wrappedSubmit;
        }
        textarea.form.submit = wrappedSubmit;
      }
    }

    textarea.style.display = "none";
    var instance = CodeMirror(function(node) {
      textarea.parentNode.insertBefore(node, textarea.nextSibling);
    }, options);
    instance.save = save;
    instance.getTextArea = function() { return textarea; };
    instance.toTextArea = function() {
      save();
      textarea.parentNode.removeChild(instance.getWrapperElement());
      textarea.style.display = "";
      if (textarea.form) {
        rmSubmit();
        if (typeof textarea.form.submit == "function")
          textarea.form.submit = realSubmit;
      }
    };
    return instance;
  };

  // Utility functions for working with state. Exported because modes
  // sometimes need to do this.
  function copyState(mode, state) {
    if (state === true) return state;
    if (mode.copyState) return mode.copyState(state);
    var nstate = {};
    for (var n in state) {
      var val = state[n];
      if (val instanceof Array) val = val.concat([]);
      nstate[n] = val;
    }
    return nstate;
  }
  CodeMirror.copyState = copyState;
  function startState(mode, a1, a2) {
    return mode.startState ? mode.startState(a1, a2) : true;
  }
  CodeMirror.startState = startState;

  // The character stream used by a mode's parser.
  function StringStream(string, tabSize) {
    this.pos = this.start = 0;
    this.string = string;
    this.tabSize = tabSize || 8;
  }
  StringStream.prototype = {
    eol: function() {return this.pos >= this.string.length;},
    sol: function() {return this.pos == 0;},
    peek: function() {return this.string.charAt(this.pos);},
    next: function() {
      if (this.pos < this.string.length)
        return this.string.charAt(this.pos++);
    },
    eat: function(match) {
      var ch = this.string.charAt(this.pos);
      if (typeof match == "string") var ok = ch == match;
      else var ok = ch && (match.test ? match.test(ch) : match(ch));
      if (ok) {++this.pos; return ch;}
    },
    eatWhile: function(match) {
      var start = this.pos;
      while (this.eat(match)){}
      return this.pos > start;
    },
    eatSpace: function() {
      var start = this.pos;
      while (/[\s\u00a0]/.test(this.string.charAt(this.pos))) ++this.pos;
      return this.pos > start;
    },
    skipToEnd: function() {this.pos = this.string.length;},
    skipTo: function(ch) {
      var found = this.string.indexOf(ch, this.pos);
      if (found > -1) {this.pos = found; return true;}
    },
    backUp: function(n) {this.pos -= n;},
    column: function() {return countColumn(this.string, this.start, this.tabSize);},
    indentation: function() {return countColumn(this.string, null, this.tabSize);},
    match: function(pattern, consume, caseInsensitive) {
      if (typeof pattern == "string") {
        function cased(str) {return caseInsensitive ? str.toLowerCase() : str;}
        if (cased(this.string).indexOf(cased(pattern), this.pos) == this.pos) {
          if (consume !== false) this.pos += pattern.length;
          return true;
        }
      }
      else {
        var match = this.string.slice(this.pos).match(pattern);
        if (match && consume !== false) this.pos += match[0].length;
        return match;
      }
    },
    current: function(){return this.string.slice(this.start, this.pos);}
  };
  CodeMirror.StringStream = StringStream;

  function MarkedText(from, to, className, set) {
    this.from = from; this.to = to; this.style = className; this.set = set;
  }
  MarkedText.prototype = {
    attach: function(line) { this.set.push(line); },
    detach: function(line) {
      var ix = indexOf(this.set, line);
      if (ix > -1) this.set.splice(ix, 1);
    },
    split: function(pos, lenBefore) {
      if (this.to <= pos && this.to != null) return null;
      var from = this.from < pos || this.from == null ? null : this.from - pos + lenBefore;
      var to = this.to == null ? null : this.to - pos + lenBefore;
      return new MarkedText(from, to, this.style, this.set);
    },
    dup: function() { return new MarkedText(null, null, this.style, this.set); },
    clipTo: function(fromOpen, from, toOpen, to, diff) {
      if (this.from != null && this.from >= from)
        this.from = Math.max(to, this.from) + diff;
      if (this.to != null && this.to > from)
        this.to = to < this.to ? this.to + diff : from;
      if (fromOpen && to > this.from && (to < this.to || this.to == null))
        this.from = null;
      if (toOpen && (from < this.to || this.to == null) && (from > this.from || this.from == null))
        this.to = null;
    },
    isDead: function() { return this.from != null && this.to != null && this.from >= this.to; },
    sameSet: function(x) { return this.set == x.set; }
  };

  function Bookmark(pos) {
    this.from = pos; this.to = pos; this.line = null;
  }
  Bookmark.prototype = {
    attach: function(line) { this.line = line; },
    detach: function(line) { if (this.line == line) this.line = null; },
    split: function(pos, lenBefore) {
      if (pos < this.from) {
        this.from = this.to = (this.from - pos) + lenBefore;
        return this;
      }
    },
    isDead: function() { return this.from > this.to; },
    clipTo: function(fromOpen, from, toOpen, to, diff) {
      if ((fromOpen || from < this.from) && (toOpen || to > this.to)) {
        this.from = 0; this.to = -1;
      } else if (this.from > from) {
        this.from = this.to = Math.max(to, this.from) + diff;
      }
    },
    sameSet: function(x) { return false; },
    find: function() {
      if (!this.line || !this.line.parent) return null;
      return {line: lineNo(this.line), ch: this.from};
    },
    clear: function() {
      if (this.line) {
        var found = indexOf(this.line.marked, this);
        if (found != -1) this.line.marked.splice(found, 1);
        this.line = null;
      }
    }
  };

  // Line objects. These hold state related to a line, including
  // highlighting info (the styles array).
  function Line(text, styles) {
    this.styles = styles || [text, null];
    this.text = text;
    this.height = 1;
    this.marked = this.gutterMarker = this.className = this.handlers = null;
    this.stateAfter = this.parent = this.hidden = null;
  }
  Line.inheritMarks = function(text, orig) {
    var ln = new Line(text), mk = orig && orig.marked;
    if (mk) {
      for (var i = 0; i < mk.length; ++i) {
        if (mk[i].to == null && mk[i].style) {
          var newmk = ln.marked || (ln.marked = []), mark = mk[i];
          var nmark = mark.dup(); newmk.push(nmark); nmark.attach(ln);
        }
      }
    }
    return ln;
  }
  Line.prototype = {
    // Replace a piece of a line, keeping the styles around it intact.
    replace: function(from, to_, text) {
      var st = [], mk = this.marked, to = to_ == null ? this.text.length : to_;
      copyStyles(0, from, this.styles, st);
      if (text) st.push(text, null);
      copyStyles(to, this.text.length, this.styles, st);
      this.styles = st;
      this.text = this.text.slice(0, from) + text + this.text.slice(to);
      this.stateAfter = null;
      if (mk) {
        var diff = text.length - (to - from);
        for (var i = 0; i < mk.length; ++i) {
          var mark = mk[i];
          mark.clipTo(from == null, from || 0, to_ == null, to, diff);
          if (mark.isDead()) {mark.detach(this); mk.splice(i--, 1);}
        }
      }
    },
    // Split a part off a line, keeping styles and markers intact.
    split: function(pos, textBefore) {
      var st = [textBefore, null], mk = this.marked;
      copyStyles(pos, this.text.length, this.styles, st);
      var taken = new Line(textBefore + this.text.slice(pos), st);
      if (mk) {
        for (var i = 0; i < mk.length; ++i) {
          var mark = mk[i];
          var newmark = mark.split(pos, textBefore.length);
          if (newmark) {
            if (!taken.marked) taken.marked = [];
            taken.marked.push(newmark); newmark.attach(taken);
          }
        }
      }
      return taken;
    },
    append: function(line) {
      var mylen = this.text.length, mk = line.marked, mymk = this.marked;
      this.text += line.text;
      copyStyles(0, line.text.length, line.styles, this.styles);
      if (mymk) {
        for (var i = 0; i < mymk.length; ++i)
          if (mymk[i].to == null) mymk[i].to = mylen;
      }
      if (mk && mk.length) {
        if (!mymk) this.marked = mymk = [];
        outer: for (var i = 0; i < mk.length; ++i) {
          var mark = mk[i];
          if (!mark.from) {
            for (var j = 0; j < mymk.length; ++j) {
              var mymark = mymk[j];
              if (mymark.to == mylen && mymark.sameSet(mark)) {
                mymark.to = mark.to == null ? null : mark.to + mylen;
                if (mymark.isDead()) {
                  mymark.detach(this);
                  mk.splice(i--, 1);
                }
                continue outer;
              }
            }
          }
          mymk.push(mark);
          mark.attach(this);
          mark.from += mylen;
          if (mark.to != null) mark.to += mylen;
        }
      }
    },
    fixMarkEnds: function(other) {
      var mk = this.marked, omk = other.marked;
      if (!mk) return;
      for (var i = 0; i < mk.length; ++i) {
        var mark = mk[i], close = mark.to == null;
        if (close && omk) {
          for (var j = 0; j < omk.length; ++j)
            if (omk[j].sameSet(mark)) {close = false; break;}
        }
        if (close) mark.to = this.text.length;
      }
    },
    fixMarkStarts: function() {
      var mk = this.marked;
      if (!mk) return;
      for (var i = 0; i < mk.length; ++i)
        if (mk[i].from == null) mk[i].from = 0;
    },
    addMark: function(mark) {
      mark.attach(this);
      if (this.marked == null) this.marked = [];
      this.marked.push(mark);
      this.marked.sort(function(a, b){return (a.from || 0) - (b.from || 0);});
    },
    // Run the given mode's parser over a line, update the styles
    // array, which contains alternating fragments of text and CSS
    // classes.
    highlight: function(mode, state, tabSize) {
      var stream = new StringStream(this.text, tabSize), st = this.styles, pos = 0;
      var changed = false, curWord = st[0], prevWord;
      if (this.text == "" && mode.blankLine) mode.blankLine(state);
      while (!stream.eol()) {
        var style = mode.token(stream, state);
        var substr = this.text.slice(stream.start, stream.pos);
        stream.start = stream.pos;
        if (pos && st[pos-1] == style)
          st[pos-2] += substr;
        else if (substr) {
          if (!changed && (st[pos+1] != style || (pos && st[pos-2] != prevWord))) changed = true;
          st[pos++] = substr; st[pos++] = style;
          prevWord = curWord; curWord = st[pos];
        }
        // Give up when line is ridiculously long
        if (stream.pos > 5000) {
          st[pos++] = this.text.slice(stream.pos); st[pos++] = null;
          break;
        }
      }
      if (st.length != pos) {st.length = pos; changed = true;}
      if (pos && st[pos-2] != prevWord) changed = true;
      // Short lines with simple highlights return null, and are
      // counted as changed by the driver because they are likely to
      // highlight the same way in various contexts.
      return changed || (st.length < 5 && this.text.length < 10 ? null : false);
    },
    // Fetch the parser token for a given character. Useful for hacks
    // that want to inspect the mode state (say, for completion).
    getTokenAt: function(mode, state, ch) {
      var txt = this.text, stream = new StringStream(txt);
      while (stream.pos < ch && !stream.eol()) {
        stream.start = stream.pos;
        var style = mode.token(stream, state);
      }
      return {start: stream.start,
              end: stream.pos,
              string: stream.current(),
              className: style || null,
              state: state};
    },
    indentation: function(tabSize) {return countColumn(this.text, null, tabSize);},
    // Produces an HTML fragment for the line, taking selection,
    // marking, and highlighting into account.
    getHTML: function(tabText, endAt) {
      var html = [], first = true;
      function span(text, style) {
        if (!text) return;
        // Work around a bug where, in some compat modes, IE ignores leading spaces
        if (first && ie && text.charAt(0) == " ") text = "\u00a0" + text.slice(1);
        first = false;
        if (style) html.push('<span class="', style, '">', htmlEscape(text).replace(/\t/g, tabText), "</span>");
        else html.push(htmlEscape(text).replace(/\t/g, tabText));
      }
      var st = this.styles, allText = this.text, marked = this.marked;
      var len = allText.length;
      if (endAt != null) len = Math.min(endAt, len);
      function styleToClass(style) {
        if (!style) return null;
        return "cm-" + style.replace(/ +/g, " cm-");
      }

      if (!allText && endAt == null)
        span(" ");
      else if (!marked || !marked.length)
        for (var i = 0, ch = 0; ch < len; i+=2) {
          var str = st[i], style = st[i+1], l = str.length;
          if (ch + l > len) str = str.slice(0, len - ch);
          ch += l;
          span(str, styleToClass(style));
        }
      else {
        var pos = 0, i = 0, text = "", style, sg = 0;
        var nextChange = marked[0].from || 0, marks = [], markpos = 0;
        function advanceMarks() {
          var m;
          while (markpos < marked.length &&
                 ((m = marked[markpos]).from == pos || m.from == null)) {
            if (m.style != null) marks.push(m);
            ++markpos;
          }
          nextChange = markpos < marked.length ? marked[markpos].from : Infinity;
          for (var i = 0; i < marks.length; ++i) {
            var to = marks[i].to || Infinity;
            if (to == pos) marks.splice(i--, 1);
            else nextChange = Math.min(to, nextChange);
          }
        }
        var m = 0;
        while (pos < len) {
          if (nextChange == pos) advanceMarks();
          var upto = Math.min(len, nextChange);
          while (true) {
            if (text) {
              var end = pos + text.length;
              var appliedStyle = style;
              for (var j = 0; j < marks.length; ++j)
                appliedStyle = (appliedStyle ? appliedStyle + " " : "") + marks[j].style;
              span(end > upto ? text.slice(0, upto - pos) : text, appliedStyle);
              if (end >= upto) {text = text.slice(upto - pos); pos = upto; break;}
              pos = end;
            }
            text = st[i++]; style = styleToClass(st[i++]);
          }
        }
      }
      return html.join("");
    },
    cleanUp: function() {
      this.parent = null;
      if (this.marked)
        for (var i = 0, e = this.marked.length; i < e; ++i) this.marked[i].detach(this);
    }
  };
  // Utility used by replace and split above
  function copyStyles(from, to, source, dest) {
    for (var i = 0, pos = 0, state = 0; pos < to; i+=2) {
      var part = source[i], end = pos + part.length;
      if (state == 0) {
        if (end > from) dest.push(part.slice(from - pos, Math.min(part.length, to - pos)), source[i+1]);
        if (end >= from) state = 1;
      }
      else if (state == 1) {
        if (end > to) dest.push(part.slice(0, to - pos), source[i+1]);
        else dest.push(part, source[i+1]);
      }
      pos = end;
    }
  }

  // Data structure that holds the sequence of lines.
  function LeafChunk(lines) {
    this.lines = lines;
    this.parent = null;
    for (var i = 0, e = lines.length, height = 0; i < e; ++i) {
      lines[i].parent = this;
      height += lines[i].height;
    }
    this.height = height;
  }
  LeafChunk.prototype = {
    chunkSize: function() { return this.lines.length; },
    remove: function(at, n, callbacks) {
      for (var i = at, e = at + n; i < e; ++i) {
        var line = this.lines[i];
        this.height -= line.height;
        line.cleanUp();
        if (line.handlers)
          for (var j = 0; j < line.handlers.length; ++j) callbacks.push(line.handlers[j]);
      }
      this.lines.splice(at, n);
    },
    collapse: function(lines) {
      lines.splice.apply(lines, [lines.length, 0].concat(this.lines));
    },
    insertHeight: function(at, lines, height) {
      this.height += height;
      this.lines.splice.apply(this.lines, [at, 0].concat(lines));
      for (var i = 0, e = lines.length; i < e; ++i) lines[i].parent = this;
    },
    iterN: function(at, n, op) {
      for (var e = at + n; at < e; ++at)
        if (op(this.lines[at])) return true;
    }
  };
  function BranchChunk(children) {
    this.children = children;
    var size = 0, height = 0;
    for (var i = 0, e = children.length; i < e; ++i) {
      var ch = children[i];
      size += ch.chunkSize(); height += ch.height;
      ch.parent = this;
    }
    this.size = size;
    this.height = height;
    this.parent = null;
  }
  BranchChunk.prototype = {
    chunkSize: function() { return this.size; },
    remove: function(at, n, callbacks) {
      this.size -= n;
      for (var i = 0; i < this.children.length; ++i) {
        var child = this.children[i], sz = child.chunkSize();
        if (at < sz) {
          var rm = Math.min(n, sz - at), oldHeight = child.height;
          child.remove(at, rm, callbacks);
          this.height -= oldHeight - child.height;
          if (sz == rm) { this.children.splice(i--, 1); child.parent = null; }
          if ((n -= rm) == 0) break;
          at = 0;
        } else at -= sz;
      }
      if (this.size - n < 25) {
        var lines = [];
        this.collapse(lines);
        this.children = [new LeafChunk(lines)];
        this.children[0].parent = this;
      }
    },
    collapse: function(lines) {
      for (var i = 0, e = this.children.length; i < e; ++i) this.children[i].collapse(lines);
    },
    insert: function(at, lines) {
      var height = 0;
      for (var i = 0, e = lines.length; i < e; ++i) height += lines[i].height;
      this.insertHeight(at, lines, height);
    },
    insertHeight: function(at, lines, height) {
      this.size += lines.length;
      this.height += height;
      for (var i = 0, e = this.children.length; i < e; ++i) {
        var child = this.children[i], sz = child.chunkSize();
        if (at <= sz) {
          child.insertHeight(at, lines, height);
          if (child.lines && child.lines.length > 50) {
            while (child.lines.length > 50) {
              var spilled = child.lines.splice(child.lines.length - 25, 25);
              var newleaf = new LeafChunk(spilled);
              child.height -= newleaf.height;
              this.children.splice(i + 1, 0, newleaf);
              newleaf.parent = this;
            }
            this.maybeSpill();
          }
          break;
        }
        at -= sz;
      }
    },
    maybeSpill: function() {
      if (this.children.length <= 10) return;
      var me = this;
      do {
        var spilled = me.children.splice(me.children.length - 5, 5);
        var sibling = new BranchChunk(spilled);
        if (!me.parent) { // Become the parent node
          var copy = new BranchChunk(me.children);
          copy.parent = me;
          me.children = [copy, sibling];
          me = copy;
        } else {
          me.size -= sibling.size;
          me.height -= sibling.height;
          var myIndex = indexOf(me.parent.children, me);
          me.parent.children.splice(myIndex + 1, 0, sibling);
        }
        sibling.parent = me.parent;
      } while (me.children.length > 10);
      me.parent.maybeSpill();
    },
    iter: function(from, to, op) { this.iterN(from, to - from, op); },
    iterN: function(at, n, op) {
      for (var i = 0, e = this.children.length; i < e; ++i) {
        var child = this.children[i], sz = child.chunkSize();
        if (at < sz) {
          var used = Math.min(n, sz - at);
          if (child.iterN(at, used, op)) return true;
          if ((n -= used) == 0) break;
          at = 0;
        } else at -= sz;
      }
    }
  };

  function getLineAt(chunk, n) {
    while (!chunk.lines) {
      for (var i = 0;; ++i) {
        var child = chunk.children[i], sz = child.chunkSize();
        if (n < sz) { chunk = child; break; }
        n -= sz;
      }
    }
    return chunk.lines[n];
  }
  function lineNo(line) {
    if (line.parent == null) return null;
    var cur = line.parent, no = indexOf(cur.lines, line);
    for (var chunk = cur.parent; chunk; cur = chunk, chunk = chunk.parent) {
      for (var i = 0, e = chunk.children.length; ; ++i) {
        if (chunk.children[i] == cur) break;
        no += chunk.children[i].chunkSize();
      }
    }
    return no;
  }
  function lineAtHeight(chunk, h) {
    var n = 0;
    outer: do {
      for (var i = 0, e = chunk.children.length; i < e; ++i) {
        var child = chunk.children[i], ch = child.height;
        if (h < ch) { chunk = child; continue outer; }
        h -= ch;
        n += child.chunkSize();
      }
      return n;
    } while (!chunk.lines);
    for (var i = 0, e = chunk.lines.length; i < e; ++i) {
      var line = chunk.lines[i], lh = line.height;
      if (h < lh) break;
      h -= lh;
    }
    return n + i;
  }
  function heightAtLine(chunk, n) {
    var h = 0;
    outer: do {
      for (var i = 0, e = chunk.children.length; i < e; ++i) {
        var child = chunk.children[i], sz = child.chunkSize();
        if (n < sz) { chunk = child; continue outer; }
        n -= sz;
        h += child.height;
      }
      return h;
    } while (!chunk.lines);
    for (var i = 0; i < n; ++i) h += chunk.lines[i].height;
    return h;
  }

  // The history object 'chunks' changes that are made close together
  // and at almost the same time into bigger undoable units.
  function History() {
    this.time = 0;
    this.done = []; this.undone = [];
  }
  History.prototype = {
    addChange: function(start, added, old) {
      this.undone.length = 0;
      var time = +new Date, cur = this.done[this.done.length - 1], last = cur && cur[cur.length - 1];
      var dtime = time - this.time;
      if (dtime > 400 || !last) {
        this.done.push([{start: start, added: added, old: old}]);
      } else if (last.start > start + added || last.start + last.added < start - last.added + last.old.length) {
        cur.push({start: start, added: added, old: old});
      } else {
        var oldoff = 0;
        if (start < last.start) {
          for (var i = last.start - start - 1; i >= 0; --i)
            last.old.unshift(old[i]);
          last.added += last.start - start;
          last.start = start;
        }
        else if (last.start < start) {
          oldoff = start - last.start;
          added += oldoff;
        }
        for (var i = last.added - oldoff, e = old.length; i < e; ++i)
          last.old.push(old[i]);
        if (last.added < added) last.added = added;
      }
      this.time = time;
    }
  };

  function stopMethod() {e_stop(this);}
  // Ensure an event has a stop method.
  function addStop(event) {
    if (!event.stop) event.stop = stopMethod;
    return event;
  }

  function e_preventDefault(e) {
    if (e.preventDefault) e.preventDefault();
    else e.returnValue = false;
  }
  function e_stopPropagation(e) {
    if (e.stopPropagation) e.stopPropagation();
    else e.cancelBubble = true;
  }
  function e_stop(e) {e_preventDefault(e); e_stopPropagation(e);}
  CodeMirror.e_stop = e_stop;
  CodeMirror.e_preventDefault = e_preventDefault;
  CodeMirror.e_stopPropagation = e_stopPropagation;

  function e_target(e) {return e.target || e.srcElement;}
  function e_button(e) {
    if (e.which) return e.which;
    else if (e.button & 1) return 1;
    else if (e.button & 2) return 3;
    else if (e.button & 4) return 2;
  }

  // Allow 3rd-party code to override event properties by adding an override
  // object to an event object.
  function e_prop(e, prop) {
    var overridden = e.override && e.override.hasOwnProperty(prop);
    return overridden ? e.override[prop] : e[prop];
  }

  // Event handler registration. If disconnect is true, it'll return a
  // function that unregisters the handler.
  function connect(node, type, handler, disconnect) {
    if (typeof node.addEventListener == "function") {
      node.addEventListener(type, handler, false);
      if (disconnect) return function() {node.removeEventListener(type, handler, false);};
    }
    else {
      var wrapHandler = function(event) {handler(event || window.event);};
      node.attachEvent("on" + type, wrapHandler);
      if (disconnect) return function() {node.detachEvent("on" + type, wrapHandler);};
    }
  }
  CodeMirror.connect = connect;

  function Delayed() {this.id = null;}
  Delayed.prototype = {set: function(ms, f) {clearTimeout(this.id); this.id = setTimeout(f, ms);}};

  // Detect drag-and-drop
  var dragAndDrop = function() {
    // IE8 has ondragstart and ondrop properties, but doesn't seem to
    // actually support ondragstart the way it's supposed to work.
    if (/MSIE [1-8]\b/.test(navigator.userAgent)) return false;
    var div = document.createElement('div');
    return "draggable" in div;
  }();

  var gecko = /gecko\/\d{7}/i.test(navigator.userAgent);
  var ie = /MSIE \d/.test(navigator.userAgent);
  var webkit = /WebKit\//.test(navigator.userAgent);

  var lineSep = "\n";
  // Feature-detect whether newlines in textareas are converted to \r\n
  (function () {
    var te = document.createElement("textarea");
    te.value = "foo\nbar";
    if (te.value.indexOf("\r") > -1) lineSep = "\r\n";
  }());

  // Counts the column offset in a string, taking tabs into account.
  // Used mostly to find indentation.
  function countColumn(string, end, tabSize) {
    if (end == null) {
      end = string.search(/[^\s\u00a0]/);
      if (end == -1) end = string.length;
    }
    for (var i = 0, n = 0; i < end; ++i) {
      if (string.charAt(i) == "\t") n += tabSize - (n % tabSize);
      else ++n;
    }
    return n;
  }

  function computedStyle(elt) {
    if (elt.currentStyle) return elt.currentStyle;
    return window.getComputedStyle(elt, null);
  }

  // Find the position of an element by following the offsetParent chain.
  // If screen==true, it returns screen (rather than page) coordinates.
  function eltOffset(node, screen) {
    var bod = node.ownerDocument.body;
    var x = 0, y = 0, skipBody = false;
    for (var n = node; n; n = n.offsetParent) {
      var ol = n.offsetLeft, ot = n.offsetTop;
      // Firefox reports weird inverted offsets when the body has a border.
      if (n == bod) { x += Math.abs(ol); y += Math.abs(ot); }
      else { x += ol, y += ot; }
      if (screen && computedStyle(n).position == "fixed")
        skipBody = true;
    }
    var e = screen && !skipBody ? null : bod;
    for (var n = node.parentNode; n != e; n = n.parentNode)
      if (n.scrollLeft != null) { x -= n.scrollLeft; y -= n.scrollTop;}
    return {left: x, top: y};
  }
  // Use the faster and saner getBoundingClientRect method when possible.
  if (document.documentElement.getBoundingClientRect != null) eltOffset = function(node, screen) {
    // Take the parts of bounding client rect that we are interested in so we are able to edit if need be,
    // since the returned value cannot be changed externally (they are kept in sync as the element moves within the page)
    try { var box = node.getBoundingClientRect(); box = { top: box.top, left: box.left }; }
    catch(e) { box = {top: 0, left: 0}; }
    if (!screen) {
      // Get the toplevel scroll, working around browser differences.
      if (window.pageYOffset == null) {
        var t = document.documentElement || document.body.parentNode;
        if (t.scrollTop == null) t = document.body;
        box.top += t.scrollTop; box.left += t.scrollLeft;
      } else {
        box.top += window.pageYOffset; box.left += window.pageXOffset;
      }
    }
    return box;
  };

  // Get a node's text content.
  function eltText(node) {
    return node.textContent || node.innerText || node.nodeValue || "";
  }
  function selectInput(node) {
    if (ios) { // Mobile Safari apparently has a bug where select() is broken.
      node.selectionStart = 0;
      node.selectionEnd = node.value.length;
    } else node.select();
  }

  // Operations on {line, ch} objects.
  function posEq(a, b) {return a.line == b.line && a.ch == b.ch;}
  function posLess(a, b) {return a.line < b.line || (a.line == b.line && a.ch < b.ch);}
  function copyPos(x) {return {line: x.line, ch: x.ch};}

  var escapeElement = document.createElement("pre");
  function htmlEscape(str) {
    escapeElement.textContent = str;
    return escapeElement.innerHTML;
  }
  // Recent (late 2011) Opera betas insert bogus newlines at the start
  // of the textContent, so we strip those.
  if (htmlEscape("a") == "\na")
    htmlEscape = function(str) {
      escapeElement.textContent = str;
      return escapeElement.innerHTML.slice(1);
    };
  // Some IEs don't preserve tabs through innerHTML
  else if (htmlEscape("\t") != "\t")
    htmlEscape = function(str) {
      escapeElement.innerHTML = "";
      escapeElement.appendChild(document.createTextNode(str));
      return escapeElement.innerHTML;
    };
  CodeMirror.htmlEscape = htmlEscape;

  // Used to position the cursor after an undo/redo by finding the
  // last edited character.
  function editEnd(from, to) {
    if (!to) return 0;
    if (!from) return to.length;
    for (var i = from.length, j = to.length; i >= 0 && j >= 0; --i, --j)
      if (from.charAt(i) != to.charAt(j)) break;
    return j + 1;
  }

  function indexOf(collection, elt) {
    if (collection.indexOf) return collection.indexOf(elt);
    for (var i = 0, e = collection.length; i < e; ++i)
      if (collection[i] == elt) return i;
    return -1;
  }
  function isWordChar(ch) {
    return /\w/.test(ch) || ch.toUpperCase() != ch.toLowerCase();
  }

  // See if "".split is the broken IE version, if so, provide an
  // alternative way to split lines.
  var splitLines = "\n\nb".split(/\n/).length != 3 ? function(string) {
    var pos = 0, nl, result = [];
    while ((nl = string.indexOf("\n", pos)) > -1) {
      result.push(string.slice(pos, string.charAt(nl-1) == "\r" ? nl - 1 : nl));
      pos = nl + 1;
    }
    result.push(string.slice(pos));
    return result;
  } : function(string){return string.split(/\r?\n/);};
  CodeMirror.splitLines = splitLines;

  var hasSelection = window.getSelection ? function(te) {
    try { return te.selectionStart != te.selectionEnd; }
    catch(e) { return false; }
  } : function(te) {
    try {var range = te.ownerDocument.selection.createRange();}
    catch(e) {}
    if (!range || range.parentElement() != te) return false;
    return range.compareEndPoints("StartToEnd", range) != 0;
  };

  CodeMirror.defineMode("null", function() {
    return {token: function(stream) {stream.skipToEnd();}};
  });
  CodeMirror.defineMIME("text/plain", "null");

  var keyNames = {3: "Enter", 8: "Backspace", 9: "Tab", 13: "Enter", 16: "Shift", 17: "Ctrl", 18: "Alt",
                  19: "Pause", 20: "CapsLock", 27: "Esc", 32: "Space", 33: "PageUp", 34: "PageDown", 35: "End",
                  36: "Home", 37: "Left", 38: "Up", 39: "Right", 40: "Down", 44: "PrintScrn", 45: "Insert",
                  46: "Delete", 59: ";", 91: "Mod", 92: "Mod", 93: "Mod", 186: ";", 187: "=", 188: ",",
                  189: "-", 190: ".", 191: "/", 192: "`", 219: "[", 220: "\\", 221: "]", 222: "'", 63276: "PageUp",
                  63277: "PageDown", 63275: "End", 63273: "Home", 63234: "Left", 63232: "Up", 63235: "Right",
                  63233: "Down", 63302: "Insert", 63272: "Delete"};
  CodeMirror.keyNames = keyNames;
  (function() {
    // Number keys
    for (var i = 0; i < 10; i++) keyNames[i + 48] = String(i);
    // Alphabetic keys
    for (var i = 65; i <= 90; i++) keyNames[i] = String.fromCharCode(i);
    // Function keys
    for (var i = 1; i <= 12; i++) keyNames[i + 111] = keyNames[i + 63235] = "F" + i;
  })();

  return CodeMirror;
})();
