// CodeMirror is the only global var we claim
window.CodeMirror = (function() {
    "use strict";

    // BROWSER SNIFFING

    // Crude, but necessary to handle a number of hard-to-feature-detect
    // bugs and behavior differences.
    var gecko = /gecko\/\d/i.test(navigator.userAgent);
    var ie = /MSIE \d/.test(navigator.userAgent);
    var ie_lt8 = ie && (document.documentMode == null || document.documentMode < 8);
    var ie_lt9 = ie && (document.documentMode == null || document.documentMode < 9);
    var webkit = /WebKit\//.test(navigator.userAgent);
    var qtwebkit = webkit && /Qt\/\d+\.\d+/.test(navigator.userAgent);
    var chrome = /Chrome\//.test(navigator.userAgent);
    var opera = /Opera\//.test(navigator.userAgent);
    var safari = /Apple Computer/.test(navigator.vendor);
    var khtml = /KHTML\//.test(navigator.userAgent);
    var mac_geLion = /Mac OS X 1\d\D([7-9]|\d\d)\D/.test(navigator.userAgent);
    var mac_geMountainLion = /Mac OS X 1\d\D([8-9]|\d\d)\D/.test(navigator.userAgent);
    var phantom = /PhantomJS/.test(navigator.userAgent);

    var ios = /AppleWebKit/.test(navigator.userAgent) && /Mobile\/\w+/.test(navigator.userAgent);
    // This is woefully incomplete. Suggestions for alternative methods welcome.
    var mobile = ios || /Android|webOS|BlackBerry|Opera Mini|Opera Mobi|IEMobile/i.test(navigator.userAgent);
    var mac = ios || /Mac/.test(navigator.platform);
    var windows = /windows/i.test(navigator.platform);

    var opera_version = opera && navigator.userAgent.match(/Version\/(\d*\.\d*)/);
    if (opera_version) opera_version = Number(opera_version[1]);
    // Some browsers use the wrong event properties to signal cmd/ctrl on OS X
    var flipCtrlCmd = mac && (qtwebkit || opera && (opera_version == null || opera_version < 12.11));
    var captureMiddleClick = gecko || (ie && !ie_lt9);

    // Optimize some code when these features are not used
    var sawReadOnlySpans = false, sawCollapsedSpans = false;

    // CONSTRUCTOR

    function CodeMirror(place, options) {
        if (!(this instanceof CodeMirror)) return new CodeMirror(place, options);

        this.options = options = options || {};
        // Determine effective options based on given values and defaults.
        for (var opt in defaults) if (!options.hasOwnProperty(opt) && defaults.hasOwnProperty(opt))
            options[opt] = defaults[opt];
        setGuttersForLineNumbers(options);

        var docStart = typeof options.value == "string" ? 0 : options.value.first;
        var display = this.display = makeDisplay(place, docStart);
        display.wrapper.CodeMirror = this;
        updateGutters(this);
        if (options.autofocus && !mobile) focusInput(this);

        this.state = {keyMaps: [],
            overlays: [],
            modeGen: 0,
            overwrite: false, focused: false,
            suppressEdits: false, pasteIncoming: false,
            draggingText: false,
            highlight: new Delayed()};

        this.nextOpId = 0;
        themeChanged(this);
        if (options.lineWrapping)
            this.display.wrapper.className += " CodeMirror-wrap";

        var doc = options.value;
        if (typeof doc == "string") doc = new Doc(options.value, options.mode);
        operation(this, attachDoc)(this, doc);

        // Override magic textarea content restore that IE sometimes does
        // on our hidden textarea on reload
        if (ie) setTimeout(bind(resetInput, this, true), 20);

        registerEventHandlers(this);
        // IE throws unspecified error in certain cases, when
        // trying to access activeElement before onload
        var hasFocus; try { hasFocus = (document.activeElement == display.input); } catch(e) { }
        if (hasFocus || (options.autofocus && !mobile)) setTimeout(bind(onFocus, this), 20);
        else onBlur(this);

        operation(this, function() {
            for (var opt in optionHandlers)
                if (optionHandlers.propertyIsEnumerable(opt))
                    optionHandlers[opt](this, options[opt], Init);
            for (var i = 0; i < initHooks.length; ++i) initHooks[i](this);
        })();
    }

    // DISPLAY CONSTRUCTOR

    function makeDisplay(place, docStart) {
        var d = {};
        var input = d.input = elt("textarea", null, null, "position: absolute; padding: 0; width: 1px; height: 1em; outline: none;");
        if (webkit) input.style.width = "1000px";
        else input.setAttribute("wrap", "off");
        input.setAttribute("autocorrect", "off"); input.setAttribute("autocapitalize", "off");
        // Wraps and hides input textarea
        d.inputDiv = elt("div", [input], null, "overflow: hidden; position: relative; width: 3px; height: 0px;");
        // The actual fake scrollbars.
        d.scrollbarH = elt("div", [elt("div", null, null, "height: 1px")], "CodeMirror-hscrollbar");
        d.scrollbarV = elt("div", [elt("div", null, null, "width: 1px")], "CodeMirror-vscrollbar");
        d.scrollbarFiller = elt("div", null, "CodeMirror-scrollbar-filler");
        // DIVs containing the selection and the actual code
        d.lineDiv = elt("div");
        d.selectionDiv = elt("div", null, null, "position: relative; z-index: 1");
        // Blinky cursor, and element used to ensure cursor fits at the end of a line
        d.cursor = elt("div", "\u00a0", "CodeMirror-cursor");
        // Secondary cursor, shown when on a 'jump' in bi-directional text
        d.otherCursor = elt("div", "\u00a0", "CodeMirror-cursor CodeMirror-secondarycursor");
        // Used to measure text size
        d.measure = elt("div", null, "CodeMirror-measure");
        // Wraps everything that needs to exist inside the vertically-padded coordinate system
        d.lineSpace = elt("div", [d.measure, d.selectionDiv, d.lineDiv, d.cursor, d.otherCursor],
            null, "position: relative; outline: none");
        // Moved around its parent to cover visible view
        d.mover = elt("div", [elt("div", [d.lineSpace], "CodeMirror-lines")], null, "position: relative");
        // Set to the height of the text, causes scrolling
        d.sizer = elt("div", [d.mover], "CodeMirror-sizer");
        // D is needed because behavior of elts with overflow: auto and padding is inconsistent across browsers
        d.heightForcer = elt("div", "\u00a0", null, "position: absolute; height: " + scrollerCutOff + "px");
        // Will contain the gutters, if any
        d.gutters = elt("div", null, "CodeMirror-gutters");
        d.lineGutter = null;
        // Helper element to properly size the gutter backgrounds
        var scrollerInner = elt("div", [d.sizer, d.heightForcer, d.gutters], null, "position: relative; min-height: 100%");
        // Provides scrolling
        d.scroller = elt("div", [scrollerInner], "CodeMirror-scroll");
        d.scroller.setAttribute("tabIndex", "-1");
        // The element in which the editor lives.
        d.wrapper = elt("div", [d.inputDiv, d.scrollbarH, d.scrollbarV,
            d.scrollbarFiller, d.scroller], "CodeMirror");
        // Work around IE7 z-index bug
        if (ie_lt8) { d.gutters.style.zIndex = -1; d.scroller.style.paddingRight = 0; }
        if (place.appendChild) place.appendChild(d.wrapper); else place(d.wrapper);

        // Needed to hide big blue blinking cursor on Mobile Safari
        if (ios) input.style.width = "0px";
        if (!webkit) d.scroller.draggable = true;
        // Needed to handle Tab key in KHTML
        if (khtml) { d.inputDiv.style.height = "1px"; d.inputDiv.style.position = "absolute"; }
        // Need to set a minimum width to see the scrollbar on IE7 (but must not set it on IE8).
        else if (ie_lt8) d.scrollbarH.style.minWidth = d.scrollbarV.style.minWidth = "18px";

        // Current visible range (may be bigger than the view window).
        d.viewOffset = d.lastSizeC = 0;
        d.showingFrom = d.showingTo = docStart;

        // Used to only resize the line number gutter when necessary (when
        // the amount of lines crosses a boundary that makes its width change)
        d.lineNumWidth = d.lineNumInnerWidth = d.lineNumChars = null;
        // See readInput and resetInput
        d.prevInput = "";
        // Set to true when a non-horizontal-scrolling widget is added. As
        // an optimization, widget aligning is skipped when d is false.
        d.alignWidgets = false;
        // Flag that indicates whether we currently expect input to appear
        // (after some event like 'keypress' or 'input') and are polling
        // intensively.
        d.pollingFast = false;
        // Self-resetting timeout for the poller
        d.poll = new Delayed();
        // True when a drag from the editor is active
        d.draggingText = false;

        d.cachedCharWidth = d.cachedTextHeight = null;
        d.measureLineCache = [];
        d.measureLineCachePos = 0;

        // Tracks when resetInput has punted to just putting a short
        // string instead of the (large) selection.
        d.inaccurateSelection = false;

        // Tracks the maximum line length so that the horizontal scrollbar
        // can be kept static when scrolling.
        d.maxLine = null;
        d.maxLineLength = 0;
        d.maxLineChanged = false;

        // Used for measuring wheel scrolling granularity
        d.wheelDX = d.wheelDY = d.wheelStartX = d.wheelStartY = null;

        return d;
    }

    // STATE UPDATES

    // Used to get the editor into a consistent state again when options change.

    function loadMode(cm) {
        cm.doc.mode = CodeMirror.getMode(cm.options, cm.doc.modeOption);
        cm.doc.iter(function(line) {
            if (line.stateAfter) line.stateAfter = null;
            if (line.styles) line.styles = null;
        });
        cm.doc.frontier = cm.doc.first;
        startWorker(cm, 100);
        cm.state.modeGen++;
        if (cm.curOp) regChange(cm);
    }

    function wrappingChanged(cm) {
        if (cm.options.lineWrapping) {
            cm.display.wrapper.className += " CodeMirror-wrap";
            cm.display.sizer.style.minWidth = "";
        } else {
            cm.display.wrapper.className = cm.display.wrapper.className.replace(" CodeMirror-wrap", "");
            computeMaxLength(cm);
        }
        estimateLineHeights(cm);
        regChange(cm);
        clearCaches(cm);
        setTimeout(function(){updateScrollbars(cm.display, cm.doc.height);}, 100);
    }

    function estimateHeight(cm) {
        var th = textHeight(cm.display), wrapping = cm.options.lineWrapping;
        var perLine = wrapping && Math.max(5, cm.display.scroller.clientWidth / charWidth(cm.display) - 3);
        return function(line) {
            if (lineIsHidden(cm.doc, line))
                return 0;
            else if (wrapping)
                return (Math.ceil(line.text.length / perLine) || 1) * th;
            else
                return th;
        };
    }

    function estimateLineHeights(cm) {
        var doc = cm.doc, est = estimateHeight(cm);
        doc.iter(function(line) {
            var estHeight = est(line);
            if (estHeight != line.height) updateLineHeight(line, estHeight);
        });
    }

    function keyMapChanged(cm) {
        var style = keyMap[cm.options.keyMap].style;
        cm.display.wrapper.className = cm.display.wrapper.className.replace(/\s*cm-keymap-\S+/g, "") +
            (style ? " cm-keymap-" + style : "");
    }

    function themeChanged(cm) {
        cm.display.wrapper.className = cm.display.wrapper.className.replace(/\s*cm-s-\S+/g, "") +
            cm.options.theme.replace(/(^|\s)\s*/g, " cm-s-");
        clearCaches(cm);
    }

    function guttersChanged(cm) {
        updateGutters(cm);
        regChange(cm);
    }

    function updateGutters(cm) {
        var gutters = cm.display.gutters, specs = cm.options.gutters;
        removeChildren(gutters);
        for (var i = 0; i < specs.length; ++i) {
            var gutterClass = specs[i];
            var gElt = gutters.appendChild(elt("div", null, "CodeMirror-gutter " + gutterClass));
            if (gutterClass == "CodeMirror-linenumbers") {
                cm.display.lineGutter = gElt;
                gElt.style.width = (cm.display.lineNumWidth || 1) + "px";
            }
        }
        gutters.style.display = i ? "" : "none";
    }

    function lineLength(doc, line) {
        if (line.height == 0) return 0;
        var len = line.text.length, merged, cur = line;
        while (merged = collapsedSpanAtStart(cur)) {
            var found = merged.find();
            cur = getLine(doc, found.from.line);
            len += found.from.ch - found.to.ch;
        }
        cur = line;
        while (merged = collapsedSpanAtEnd(cur)) {
            var found = merged.find();
            len -= cur.text.length - found.from.ch;
            cur = getLine(doc, found.to.line);
            len += cur.text.length - found.to.ch;
        }
        return len;
    }

    function computeMaxLength(cm) {
        var d = cm.display, doc = cm.doc;
        d.maxLine = getLine(doc, doc.first);
        d.maxLineLength = lineLength(doc, d.maxLine);
        d.maxLineChanged = true;
        doc.iter(function(line) {
            var len = lineLength(doc, line);
            if (len > d.maxLineLength) {
                d.maxLineLength = len;
                d.maxLine = line;
            }
        });
    }

    // Make sure the gutters options contains the element
    // "CodeMirror-linenumbers" when the lineNumbers option is true.
    function setGuttersForLineNumbers(options) {
        var found = false;
        for (var i = 0; i < options.gutters.length; ++i) {
            if (options.gutters[i] == "CodeMirror-linenumbers") {
                if (options.lineNumbers) found = true;
                else options.gutters.splice(i--, 1);
            }
        }
        if (!found && options.lineNumbers)
            options.gutters.push("CodeMirror-linenumbers");
    }

    // SCROLLBARS

    // Re-synchronize the fake scrollbars with the actual size of the
    // content. Optionally force a scrollTop.
    function updateScrollbars(d /* display */, docHeight) {
        var totalHeight = docHeight + 2 * paddingTop(d);
        d.sizer.style.minHeight = d.heightForcer.style.top = totalHeight + "px";
        var scrollHeight = Math.max(totalHeight, d.scroller.scrollHeight);
        var needsH = d.scroller.scrollWidth > d.scroller.clientWidth;
        var needsV = scrollHeight > d.scroller.clientHeight;
        if (needsV) {
            d.scrollbarV.style.display = "block";
            d.scrollbarV.style.bottom = needsH ? scrollbarWidth(d.measure) + "px" : "0";
            d.scrollbarV.firstChild.style.height =
                (scrollHeight - d.scroller.clientHeight + d.scrollbarV.clientHeight) + "px";
        } else d.scrollbarV.style.display = "";
        if (needsH) {
            d.scrollbarH.style.display = "block";
            d.scrollbarH.style.right = needsV ? scrollbarWidth(d.measure) + "px" : "0";
            d.scrollbarH.firstChild.style.width =
                (d.scroller.scrollWidth - d.scroller.clientWidth + d.scrollbarH.clientWidth) + "px";
        } else d.scrollbarH.style.display = "";
        if (needsH && needsV) {
            d.scrollbarFiller.style.display = "block";
            d.scrollbarFiller.style.height = d.scrollbarFiller.style.width = scrollbarWidth(d.measure) + "px";
        } else d.scrollbarFiller.style.display = "";

        if (mac_geLion && scrollbarWidth(d.measure) === 0)
            d.scrollbarV.style.minWidth = d.scrollbarH.style.minHeight = mac_geMountainLion ? "18px" : "12px";
    }

    function visibleLines(display, doc, viewPort) {
        var top = display.scroller.scrollTop, height = display.wrapper.clientHeight;
        if (typeof viewPort == "number") top = viewPort;
        else if (viewPort) {top = viewPort.top; height = viewPort.bottom - viewPort.top;}
        top = Math.floor(top - paddingTop(display));
        var bottom = Math.ceil(top + height);
        return {from: lineAtHeight(doc, top), to: lineAtHeight(doc, bottom)};
    }

    // LINE NUMBERS

    function alignHorizontally(cm) {
        var display = cm.display;
        if (!display.alignWidgets && (!display.gutters.firstChild || !cm.options.fixedGutter)) return;
        var comp = compensateForHScroll(display) - display.scroller.scrollLeft + cm.doc.scrollLeft;
        var gutterW = display.gutters.offsetWidth, l = comp + "px";
        for (var n = display.lineDiv.firstChild; n; n = n.nextSibling) if (n.alignable) {
            for (var i = 0, a = n.alignable; i < a.length; ++i) a[i].style.left = l;
        }
        if (cm.options.fixedGutter)
            display.gutters.style.left = (comp + gutterW) + "px";
    }

    function maybeUpdateLineNumberWidth(cm) {
        if (!cm.options.lineNumbers) return false;
        var doc = cm.doc, last = lineNumberFor(cm.options, doc.first + doc.size - 1), display = cm.display;
        if (last.length != display.lineNumChars) {
            var test = display.measure.appendChild(elt("div", [elt("div", last)],
                "CodeMirror-linenumber CodeMirror-gutter-elt"));
            var innerW = test.firstChild.offsetWidth, padding = test.offsetWidth - innerW;
            display.lineGutter.style.width = "";
            display.lineNumInnerWidth = Math.max(innerW, display.lineGutter.offsetWidth - padding);
            display.lineNumWidth = display.lineNumInnerWidth + padding;
            display.lineNumChars = display.lineNumInnerWidth ? last.length : -1;
            display.lineGutter.style.width = display.lineNumWidth + "px";
            return true;
        }
        return false;
    }

    function lineNumberFor(options, i) {
        return String(options.lineNumberFormatter(i + options.firstLineNumber));
    }
    function compensateForHScroll(display) {
        return getPixelRect(display.scroller).left - getPixelRect(display.sizer).left;
    }

    // DISPLAY DRAWING

    function updateDisplay(cm, changes, viewPort) {
        var oldFrom = cm.display.showingFrom, oldTo = cm.display.showingTo;
        var updated = updateDisplayInner(cm, changes, viewPort);
        if (updated) {
            signalLater(cm, "update", cm);
            if (cm.display.showingFrom != oldFrom || cm.display.showingTo != oldTo)
                signalLater(cm, "viewportChange", cm, cm.display.showingFrom, cm.display.showingTo);
        }
        updateSelection(cm);
        updateScrollbars(cm.display, cm.doc.height);

        return updated;
    }

    // Uses a set of changes plus the current scroll position to
    // determine which DOM updates have to be made, and makes the
    // updates.
    function updateDisplayInner(cm, changes, viewPort) {
        var display = cm.display, doc = cm.doc;
        if (!display.wrapper.clientWidth) {
            display.showingFrom = display.showingTo = doc.first;
            display.viewOffset = 0;
            return;
        }

        // Compute the new visible window
        // If scrollTop is specified, use that to determine which lines
        // to render instead of the current scrollbar position.
        var visible = visibleLines(display, doc, viewPort);
        // Bail out if the visible area is already rendered and nothing changed.
        if (changes.length == 0 &&
            visible.from > display.showingFrom && visible.to < display.showingTo)
            return;

        if (maybeUpdateLineNumberWidth(cm))
            changes = [{from: doc.first, to: doc.first + doc.size}];
        var gutterW = display.sizer.style.marginLeft = display.gutters.offsetWidth + "px";
        display.scrollbarH.style.left = cm.options.fixedGutter ? gutterW : "0";

        // When merged lines are present, the line that needs to be
        // redrawn might not be the one that was changed.
        if (sawCollapsedSpans)
            for (var i = 0; i < changes.length; ++i) {
                var ch = changes[i], merged;
                while (merged = collapsedSpanAtStart(getLine(doc, ch.from))) {
                    var from = merged.find().from.line;
                    if (ch.diff) ch.diff -= ch.from - from;
                    ch.from = from;
                }
            }

        // Used to determine which lines need their line numbers updated
        var positionsChangedFrom = Infinity;
        if (cm.options.lineNumbers)
            for (var i = 0; i < changes.length; ++i)
                if (changes[i].diff) { positionsChangedFrom = changes[i].from; break; }

        var end = doc.first + doc.size;
        var from = Math.max(visible.from - cm.options.viewportMargin, doc.first);
        var to = Math.min(end, visible.to + cm.options.viewportMargin);
        if (display.showingFrom < from && from - display.showingFrom < 20) from = Math.max(doc.first, display.showingFrom);
        if (display.showingTo > to && display.showingTo - to < 20) to = Math.min(end, display.showingTo);
        if (sawCollapsedSpans) {
            from = lineNo(visualLine(doc, getLine(doc, from)));
            while (to < end && lineIsHidden(doc, getLine(doc, to))) ++to;
        }

        // Create a range of theoretically intact lines, and punch holes
        // in that using the change info.
        var intact = computeIntact([{from: display.showingFrom, to: display.showingTo}], 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.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 && from == display.showingFrom && to == display.showingTo) {
            updateViewOffset(cm);
            return;
        }
        intact.sort(function(a, b) {return a.from - b.from;});

        var focused = document.activeElement;
        if (intactLines < (to - from) * .7) display.lineDiv.style.display = "none";
        patchDisplay(cm, from, to, intact, positionsChangedFrom);
        display.lineDiv.style.display = "";
        if (document.activeElement != focused && focused.offsetHeight) focused.focus();

        var different = from != display.showingFrom || to != display.showingTo ||
            display.lastSizeC != display.wrapper.clientHeight;
        // This is just a bogus formula that detects when the editor is
        // resized or the font size changes.
        if (different) display.lastSizeC = display.wrapper.clientHeight;
        display.showingFrom = from; display.showingTo = to;
        startWorker(cm, 100);

        var prevBottom = display.lineDiv.offsetTop;
        for (var node = display.lineDiv.firstChild, height; node; node = node.nextSibling) if (node.lineObj) {
            if (ie_lt8) {
                var bot = node.offsetTop + node.offsetHeight;
                height = bot - prevBottom;
                prevBottom = bot;
            } else {
                var box = getLogicalRect(node);
                height = box.bottom - box.top;
            }
            var diff = node.lineObj.height - height;
            if (height < 2) height = textHeight(display);
            if (diff > .001 || diff < -.001) {
                updateLineHeight(node.lineObj, height);
                var widgets = node.lineObj.widgets;
                if (widgets) for (var i = 0; i < widgets.length; ++i)
                    widgets[i].height = widgets[i].node.offsetHeight;
            }
        }
        updateViewOffset(cm);

        if (visibleLines(display, doc, viewPort).to >= to)
            updateDisplayInner(cm, [], viewPort);
        return true;
    }

    function updateViewOffset(cm) {
        var off = cm.display.viewOffset = heightAtLine(cm, getLine(cm.doc, cm.display.showingFrom));
        // Position the mover div to align with the current virtual scroll position
        cm.display.mover.style.top = off + "px";
    }

    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});
                } 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});
                    if (change.to < range.to)
                        intact2.push({from: change.to + diff, to: range.to + diff});
                }
            }
            intact = intact2;
        }
        return intact;
    }

    function getDimensions(cm) {
        var d = cm.display, left = {}, width = {};
        for (var n = d.gutters.firstChild, i = 0; n; n = n.nextSibling, ++i) {
            left[cm.options.gutters[i]] = n.offsetLeft;
            width[cm.options.gutters[i]] = n.offsetWidth;
        }
        return {fixedPos: compensateForHScroll(d),
            gutterTotalWidth: d.gutters.offsetWidth,
            gutterLeft: left,
            gutterWidth: width,
            wrapperWidth: d.wrapper.clientWidth};
    }

    function patchDisplay(cm, from, to, intact, updateNumbersFrom) {
        var dims = getDimensions(cm);
        var display = cm.display, lineNumbers = cm.options.lineNumbers;
        if (!intact.length && (!webkit || !cm.display.currentWheelTarget))
            removeChildren(display.lineDiv);
        var container = display.lineDiv, cur = container.firstChild;

        function rm(node) {
            var next = node.nextSibling;
            if (webkit && mac && cm.display.currentWheelTarget == node) {
                node.style.display = "none";
                node.lineObj = null;
            } else {
                node.parentNode.removeChild(node);
            }
            return next;
        }

        var nextIntact = intact.shift(), lineN = from;
        cm.doc.iter(from, to, function(line) {
            if (nextIntact && nextIntact.to == lineN) nextIntact = intact.shift();
            if (lineIsHidden(cm.doc, line)) {
                if (line.height != 0) updateLineHeight(line, 0);
                if (line.widgets && cur.previousSibling) for (var i = 0; i < line.widgets.length; ++i)
                    if (line.widgets[i].showIfHidden) {
                        var prev = cur.previousSibling;
                        if (/pre/i.test(prev.nodeName)) {
                            var wrap = elt("div", null, null, "position: relative");
                            prev.parentNode.replaceChild(wrap, prev);
                            wrap.appendChild(prev);
                            prev = wrap;
                        }
                        var wnode = prev.appendChild(elt("div", [line.widgets[i].node], "CodeMirror-linewidget"));
                        positionLineWidget(line.widgets[i], wnode, prev, dims);
                    }
            } else if (nextIntact && nextIntact.from <= lineN && nextIntact.to > lineN) {
                // This line is intact. Skip to the actual node. Update its
                // line number if needed.
                while (cur.lineObj != line) cur = rm(cur);
                if (lineNumbers && updateNumbersFrom <= lineN && cur.lineNumber)
                    setTextContent(cur.lineNumber, lineNumberFor(cm.options, lineN));
                cur = cur.nextSibling;
            } else {
                // For lines with widgets, make an attempt to find and reuse
                // the existing element, so that widgets aren't needlessly
                // removed and re-inserted into the dom
                if (line.widgets) for (var j = 0, search = cur, reuse; search && j < 20; ++j, search = search.nextSibling)
                    if (search.lineObj == line && /div/i.test(search.nodeName)) { reuse = search; break; }
                // This line needs to be generated.
                var lineNode = buildLineElement(cm, line, lineN, dims, reuse);
                if (lineNode != reuse) {
                    container.insertBefore(lineNode, cur);
                } else {
                    while (cur != reuse) cur = rm(cur);
                    cur = cur.nextSibling;
                }

                lineNode.lineObj = line;
            }
            ++lineN;
        });
        while (cur) cur = rm(cur);
    }

    function buildLineElement(cm, line, lineNo, dims, reuse) {
        var lineElement = lineContent(cm, line);
        var markers = line.gutterMarkers, display = cm.display, wrap;

        if (!cm.options.lineNumbers && !markers && !line.bgClass && !line.wrapClass && !line.widgets)
            return lineElement;

        // Lines with gutter elements, widgets or a background class need
        // to be wrapped again, and have the extra elements added to the
        // wrapper div

        if (reuse) {
            reuse.alignable = null;
            var isOk = true, widgetsSeen = 0;
            for (var n = reuse.firstChild, next; n; n = next) {
                next = n.nextSibling;
                if (!/\bCodeMirror-linewidget\b/.test(n.className)) {
                    reuse.removeChild(n);
                } else {
                    for (var i = 0, first = true; i < line.widgets.length; ++i) {
                        var widget = line.widgets[i], isFirst = false;
                        if (!widget.above) { isFirst = first; first = false; }
                        if (widget.node == n.firstChild) {
                            positionLineWidget(widget, n, reuse, dims);
                            ++widgetsSeen;
                            if (isFirst) reuse.insertBefore(lineElement, n);
                            break;
                        }
                    }
                    if (i == line.widgets.length) { isOk = false; break; }
                }
            }
            if (isOk && widgetsSeen == line.widgets.length) {
                wrap = reuse;
                reuse.className = line.wrapClass || "";
            }
        }
        if (!wrap) {
            wrap = elt("div", null, line.wrapClass, "position: relative");
            wrap.appendChild(lineElement);
        }
        // Kludge to make sure the styled element lies behind the selection (by z-index)
        if (line.bgClass)
            wrap.insertBefore(elt("div", "\u00a0", line.bgClass + " CodeMirror-linebackground"), wrap.firstChild);
        if (cm.options.lineNumbers || markers) {
            var gutterWrap = wrap.insertBefore(elt("div", null, null, "position: absolute; left: " +
                (cm.options.fixedGutter ? dims.fixedPos : -dims.gutterTotalWidth) + "px"),
                wrap.firstChild);
            if (cm.options.fixedGutter) (wrap.alignable || (wrap.alignable = [])).push(gutterWrap);
            if (cm.options.lineNumbers && (!markers || !markers["CodeMirror-linenumbers"]))
                wrap.lineNumber = gutterWrap.appendChild(
                    elt("div", lineNumberFor(cm.options, lineNo),
                        "CodeMirror-linenumber CodeMirror-gutter-elt",
                        "left: " + dims.gutterLeft["CodeMirror-linenumbers"] + "px; width: "
                            + display.lineNumInnerWidth + "px"));
            if (markers)
                for (var k = 0; k < cm.options.gutters.length; ++k) {
                    var id = cm.options.gutters[k], found = markers.hasOwnProperty(id) && markers[id];
                    if (found)
                        gutterWrap.appendChild(elt("div", [found], "CodeMirror-gutter-elt", "left: " +
                            dims.gutterLeft[id] + "px; width: " + dims.gutterWidth[id] + "px"));
                }
        }
        if (ie_lt8) wrap.style.zIndex = 2;
        if (line.widgets && wrap != reuse) for (var i = 0, ws = line.widgets; i < ws.length; ++i) {
            var widget = ws[i], node = elt("div", [widget.node], "CodeMirror-linewidget");
            positionLineWidget(widget, node, wrap, dims);
            if (widget.above)
                wrap.insertBefore(node, cm.options.lineNumbers && line.height != 0 ? gutterWrap : lineElement);
            else
                wrap.appendChild(node);
            signalLater(widget, "redraw");
        }
        return wrap;
    }

    function positionLineWidget(widget, node, wrap, dims) {
        if (widget.noHScroll) {
            (wrap.alignable || (wrap.alignable = [])).push(node);
            var width = dims.wrapperWidth;
            node.style.left = dims.fixedPos + "px";
            if (!widget.coverGutter) {
                width -= dims.gutterTotalWidth;
                node.style.paddingLeft = dims.gutterTotalWidth + "px";
            }
            node.style.width = width + "px";
        }
        if (widget.coverGutter) {
            node.style.zIndex = 5;
            node.style.position = "relative";
            if (!widget.noHScroll) node.style.marginLeft = -dims.gutterTotalWidth + "px";
        }
    }

    // SELECTION / CURSOR

    function updateSelection(cm) {
        var display = cm.display;
        var collapsed = posEq(cm.doc.sel.from, cm.doc.sel.to);
        if (collapsed || cm.options.showCursorWhenSelecting)
            updateSelectionCursor(cm);
        else
            display.cursor.style.display = display.otherCursor.style.display = "none";
        if (!collapsed)
            updateSelectionRange(cm);
        else
            display.selectionDiv.style.display = "none";

        // Move the hidden textarea near the cursor to prevent scrolling artifacts
        var headPos = cursorCoords(cm, cm.doc.sel.head, "div");
        var wrapOff = getPixelRect(display.wrapper), lineOff = getPixelRect(display.lineDiv);
        display.inputDiv.style.top = Math.max(0, Math.min(display.wrapper.clientHeight - 10,
            headPos.top + lineOff.top - wrapOff.top)) + "px";
        display.inputDiv.style.left = Math.max(0, Math.min(display.wrapper.clientWidth - 10,
            headPos.left + lineOff.left - wrapOff.left)) + "px";
    }

    // No selection, plain cursor
    function updateSelectionCursor(cm) {
        var display = cm.display, pos = cursorCoords(cm, cm.doc.sel.head, "div");
        display.cursor.style.left = pos.left + "px";
        display.cursor.style.top = pos.top + "px";
        display.cursor.style.height = Math.max(0, pos.bottom - pos.top) * cm.options.cursorHeight + "px";
        display.cursor.style.display = "";

        if (pos.other) {
            display.otherCursor.style.display = "";
            display.otherCursor.style.left = pos.other.left + "px";
            display.otherCursor.style.top = pos.other.top + "px";
            display.otherCursor.style.height = (pos.other.bottom - pos.other.top) * .85 + "px";
        } else { display.otherCursor.style.display = "none"; }
    }

    // Highlight selection
    function updateSelectionRange(cm) {
        var display = cm.display, doc = cm.doc, sel = cm.doc.sel;
        var fragment = document.createDocumentFragment();
        var clientWidth = display.lineSpace.offsetWidth, pl = paddingLeft(cm.display);

        function add(left, top, width, bottom) {
            if (top < 0) top = 0;
            fragment.appendChild(elt("div", null, "CodeMirror-selected", "position: absolute; left: " + left +
                "px; top: " + top + "px; width: " + (width == null ? clientWidth - left : width) +
                "px; height: " + (bottom - top) + "px"));
        }

        function drawForLine(line, fromArg, toArg, retTop) {
            var lineObj = getLine(doc, line);
            var lineLen = lineObj.text.length, rVal = retTop ? Infinity : -Infinity;
            function coords(ch) {
                return charCoords(cm, Pos(line, ch), "div", lineObj);
            }

            iterateBidiSections(getOrder(lineObj), fromArg || 0, toArg == null ? lineLen : toArg, function(from, to, dir) {
                var leftPos = coords(dir == "rtl" ? to - 1 : from);
                var rightPos = coords(dir == "rtl" ? from : to - 1);
                var left = leftPos.left, right = rightPos.right;
                if (rightPos.top - leftPos.top > 3) { // Different lines, draw top part
                    add(left, leftPos.top, null, leftPos.bottom);
                    left = pl;
                    if (leftPos.bottom < rightPos.top) add(left, leftPos.bottom, null, rightPos.top);
                }
                if (toArg == null && to == lineLen) right = clientWidth;
                if (fromArg == null && from == 0) left = pl;
                rVal = retTop ? Math.min(rightPos.top, rVal) : Math.max(rightPos.bottom, rVal);
                if (left < pl + 1) left = pl;
                add(left, rightPos.top, right - left, rightPos.bottom);
            });
            return rVal;
        }

        if (sel.from.line == sel.to.line) {
            drawForLine(sel.from.line, sel.from.ch, sel.to.ch);
        } else {
            var fromObj = getLine(doc, sel.from.line);
            var cur = fromObj, merged, path = [sel.from.line, sel.from.ch], singleLine;
            while (merged = collapsedSpanAtEnd(cur)) {
                var found = merged.find();
                path.push(found.from.ch, found.to.line, found.to.ch);
                if (found.to.line == sel.to.line) {
                    path.push(sel.to.ch);
                    singleLine = true;
                    break;
                }
                cur = getLine(doc, found.to.line);
            }

            // This is a single, merged line
            if (singleLine) {
                for (var i = 0; i < path.length; i += 3)
                    drawForLine(path[i], path[i+1], path[i+2]);
            } else {
                var middleTop, middleBot, toObj = getLine(doc, sel.to.line);
                if (sel.from.ch)
                // Draw the first line of selection.
                    middleTop = drawForLine(sel.from.line, sel.from.ch, null, false);
                else
                // Simply include it in the middle block.
                    middleTop = heightAtLine(cm, fromObj) - display.viewOffset;

                if (!sel.to.ch)
                    middleBot = heightAtLine(cm, toObj) - display.viewOffset;
                else
                    middleBot = drawForLine(sel.to.line, collapsedSpanAtStart(toObj) ? null : 0, sel.to.ch, true);

                if (middleTop < middleBot) add(pl, middleTop, null, middleBot);
            }
        }

        removeChildrenAndAdd(display.selectionDiv, fragment);
        display.selectionDiv.style.display = "";
    }

    // Cursor-blinking
    function restartBlink(cm) {
        var display = cm.display;
        clearInterval(display.blinker);
        var on = true;
        display.cursor.style.visibility = display.otherCursor.style.visibility = "";
        display.blinker = setInterval(function() {
            if (!display.cursor.offsetHeight) return;
            display.cursor.style.visibility = display.otherCursor.style.visibility = (on = !on) ? "" : "hidden";
        }, cm.options.cursorBlinkRate);
    }

    // HIGHLIGHT WORKER

    function startWorker(cm, time) {
        if (cm.doc.mode.startState && cm.doc.frontier < cm.display.showingTo)
            cm.state.highlight.set(time, bind(highlightWorker, cm));
    }

    function highlightWorker(cm) {
        var doc = cm.doc;
        if (doc.frontier < doc.first) doc.frontier = doc.first;
        if (doc.frontier >= cm.display.showingTo) return;
        var end = +new Date + cm.options.workTime;
        var state = copyState(doc.mode, getStateBefore(cm, doc.frontier));
        var changed = [], prevChange;
        doc.iter(doc.frontier, Math.min(doc.first + doc.size, cm.display.showingTo + 500), function(line) {
            if (doc.frontier >= cm.display.showingFrom) { // Visible
                var oldStyles = line.styles;
                line.styles = highlightLine(cm, line, state);
                var ischange = !oldStyles || oldStyles.length != line.styles.length;
                for (var i = 0; !ischange && i < oldStyles.length; ++i) ischange = oldStyles[i] != line.styles[i];
                if (ischange) {
                    if (prevChange && prevChange.end == doc.frontier) prevChange.end++;
                    else changed.push(prevChange = {start: doc.frontier, end: doc.frontier + 1});
                }
                line.stateAfter = copyState(doc.mode, state);
            } else {
                processLine(cm, line, state);
                line.stateAfter = doc.frontier % 5 == 0 ? copyState(doc.mode, state) : null;
            }
            ++doc.frontier;
            if (+new Date > end) {
                startWorker(cm, cm.options.workDelay);
                return true;
            }
        });
        if (changed.length)
            operation(cm, function() {
                for (var i = 0; i < changed.length; ++i)
                    regChange(this, changed[i].start, changed[i].end);
            })();
    }

    // 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(cm, n) {
        var minindent, minline, doc = cm.doc;
        for (var search = n, lim = n - 100; search > lim; --search) {
            if (search <= doc.first) return doc.first;
            var line = getLine(doc, search - 1);
            if (line.stateAfter) return search;
            var indented = countColumn(line.text, null, cm.options.tabSize);
            if (minline == null || minindent > indented) {
                minline = search - 1;
                minindent = indented;
            }
        }
        return minline;
    }

    function getStateBefore(cm, n) {
        var doc = cm.doc, display = cm.display;
        if (!doc.mode.startState) return true;
        var pos = findStartLine(cm, n), state = pos > doc.first && getLine(doc, pos-1).stateAfter;
        if (!state) state = startState(doc.mode);
        else state = copyState(doc.mode, state);
        doc.iter(pos, n, function(line) {
            processLine(cm, line, state);
            var save = pos == n - 1 || pos % 5 == 0 || pos >= display.showingFrom && pos < display.showingTo;
            line.stateAfter = save ? copyState(doc.mode, state) : null;
            ++pos;
        });
        return state;
    }

    // POSITION MEASUREMENT

    function paddingTop(display) {return display.lineSpace.offsetTop;}
    function paddingLeft(display) {
        var e = removeChildrenAndAdd(display.measure, elt("pre")).appendChild(elt("span", "x"));
        return e.offsetLeft;
    }

    function measureChar(cm, line, ch, data) {
        var dir = -1;
        data = data || measureLine(cm, line);

        for (var pos = ch;; pos += dir) {
            var r = data[pos];
            if (r) break;
            if (dir < 0 && pos == 0) dir = 1;
        }
        return {left: pos < ch ? r.right : r.left,
            right: pos > ch ? r.left : r.right,
            top: r.top, bottom: r.bottom};
    }

    function measureLine(cm, line) {
        // First look in the cache
        var display = cm.display, cache = cm.display.measureLineCache;
        for (var i = 0; i < cache.length; ++i) {
            var memo = cache[i];
            if (memo.text == line.text && memo.markedSpans == line.markedSpans &&
                display.scroller.clientWidth == memo.width &&
                memo.classes == line.textClass + "|" + line.bgClass + "|" + line.wrapClass)
                return memo.measure;
        }

        var measure = measureLineInner(cm, line);
        // Store result in the cache
        var memo = {text: line.text, width: display.scroller.clientWidth,
            markedSpans: line.markedSpans, measure: measure,
            classes: line.textClass + "|" + line.bgClass + "|" + line.wrapClass};
        if (cache.length == 16) cache[++display.measureLineCachePos % 16] = memo;
        else cache.push(memo);
        return measure;
    }

    function measureLineInner(cm, line) {
        var display = cm.display, measure = emptyArray(line.text.length);
        var pre = lineContent(cm, line, measure);

        // IE does not cache element positions of inline elements between
        // calls to getBoundingClientRect. This makes the loop below,
        // which gathers the positions of all the characters on the line,
        // do an amount of layout work quadratic to the number of
        // characters. When line wrapping is off, we try to improve things
        // by first subdividing the line into a bunch of inline blocks, so
        // that IE can reuse most of the layout information from caches
        // for those blocks. This does interfere with line wrapping, so it
        // doesn't work when wrapping is on, but in that case the
        // situation is slightly better, since IE does cache line-wrapping
        // information and only recomputes per-line.
        if (ie && !ie_lt8 && !cm.options.lineWrapping && pre.childNodes.length > 100) {
            var fragment = document.createDocumentFragment();
            var chunk = 10, n = pre.childNodes.length;
            for (var i = 0, chunks = Math.ceil(n / chunk); i < chunks; ++i) {
                var wrap = elt("div", null, null, "display: inline-block");
                for (var j = 0; j < chunk && n; ++j) {
                    wrap.appendChild(pre.firstChild);
                    --n;
                }
                fragment.appendChild(wrap);
            }
            pre.appendChild(fragment);
        }

        removeChildrenAndAdd(display.measure, pre);

        var outer = getLogicalRect(display.lineDiv);
        var vranges = [], data = emptyArray(line.text.length), maxBot = pre.offsetHeight;
        // Work around an IE7/8 bug where it will sometimes have randomly
        // replaced our pre with a clone at this point.
        if (ie_lt9 && display.measure.first != pre)
            removeChildrenAndAdd(display.measure, pre);

        for (var i = 0, cur; i < measure.length; ++i) if (cur = measure[i]) {
            var size = getLogicalRect(cur);
            var top = Math.max(0, size.top - outer.top), bot = Math.min(size.bottom - outer.top, maxBot);
            for (var j = 0; j < vranges.length; j += 2) {
                var rtop = vranges[j], rbot = vranges[j+1];
                if (rtop > bot || rbot < top) continue;
                if (rtop <= top && rbot >= bot ||
                    top <= rtop && bot >= rbot ||
                    Math.min(bot, rbot) - Math.max(top, rtop) >= (bot - top) >> 1) {
                    vranges[j] = Math.min(top, rtop);
                    vranges[j+1] = Math.max(bot, rbot);
                    break;
                }
            }
            if (j == vranges.length) vranges.push(top, bot);
            data[i] = {left: size.left - outer.left, right: size.right - outer.left, top: j};
        }
        for (var i = 0, cur; i < data.length; ++i) if (cur = data[i]) {
            var vr = cur.top;
            cur.top = vranges[vr]; cur.bottom = vranges[vr+1];
        }
        if (!cm.options.lineWrapping) {
            var last = pre.lastChild;
            if (last.nodeType == 3) last = pre.appendChild(elt("span", "\u200b"));
            data.width = getPixelRect(last).right - outer.left;
        }

        return data;
    }

    function clearCaches(cm) {
        cm.display.measureLineCache.length = cm.display.measureLineCachePos = 0;
        cm.display.cachedCharWidth = cm.display.cachedTextHeight = null;
        cm.display.maxLineChanged = true;
        cm.display.lineNumChars = null;
    }

    // Context is one of "line", "div" (display.lineDiv), "local"/null (editor), or "page"
    function intoCoordSystem(cm, lineObj, rect, context) {
        if (lineObj.widgets) for (var i = 0; i < lineObj.widgets.length; ++i) if (lineObj.widgets[i].above) {
            var size = widgetHeight(lineObj.widgets[i]);
            rect.top += size; rect.bottom += size;
        }
        if (context == "line") return rect;
        if (!context) context = "local";
        var yOff = heightAtLine(cm, lineObj);
        if (context != "local") yOff -= cm.display.viewOffset;
        if (context == "page") {
            var lOff = getPixelRect(cm.display.lineSpace);
            yOff += lOff.top + (window.pageYOffset || (document.documentElement || document.body).scrollTop);
            var xOff = lOff.left + (window.pageXOffset || (document.documentElement || document.body).scrollLeft);
            rect.left += xOff; rect.right += xOff;
        }
        rect.top += yOff; rect.bottom += yOff;
        return rect;
    }

    function charCoords(cm, pos, context, lineObj) {
        if (!lineObj) lineObj = getLine(cm.doc, pos.line);
        return intoCoordSystem(cm, lineObj, measureChar(cm, lineObj, pos.ch), context);
    }

    function cursorCoords(cm, pos, context, lineObj, measurement) {
        lineObj = lineObj || getLine(cm.doc, pos.line);
        if (!measurement) measurement = measureLine(cm, lineObj);
        function get(ch, right) {
            var m = measureChar(cm, lineObj, ch, measurement);
            if (right) m.left = m.right; else m.right = m.left;
            return intoCoordSystem(cm, lineObj, m, context);
        }
        var order = getOrder(lineObj), ch = pos.ch;
        if (!order) return get(ch);
        var main, other, linedir = order[0].level;
        for (var i = 0; i < order.length; ++i) {
            var part = order[i], rtl = part.level % 2, nb, here;
            if (part.from < ch && part.to > ch) return get(ch, rtl);
            var left = rtl ? part.to : part.from, right = rtl ? part.from : part.to;
            if (left == ch) {
                // Opera and IE return bogus offsets and widths for edges
                // where the direction flips, but only for the side with the
                // lower level. So we try to use the side with the higher
                // level.
                if (i && part.level < (nb = order[i-1]).level) here = get(nb.level % 2 ? nb.from : nb.to - 1, true);
                else here = get(rtl && part.from != part.to ? ch - 1 : ch);
                if (rtl == linedir) main = here; else other = here;
            } else if (right == ch) {
                var nb = i < order.length - 1 && order[i+1];
                if (!rtl && nb && nb.from == nb.to) continue;
                if (nb && part.level < nb.level) here = get(nb.level % 2 ? nb.to - 1 : nb.from);
                else here = get(rtl ? ch : ch - 1, true);
                if (rtl == linedir) main = here; else other = here;
            }
        }
        if (linedir && !ch) other = get(order[0].to - 1);
        if (!main) return other;
        if (other) main.other = other;
        return main;
    }

    // Coords must be lineSpace-local
    function coordsChar(cm, x, y) {
        var doc = cm.doc;
        y += cm.display.viewOffset;
        if (y < 0) return {line: doc.first, ch: 0, outside: true};
        var lineNo = lineAtHeight(doc, y), last = doc.first + doc.size - 1;
        if (lineNo > last)
            return Pos(doc.size - 1, getLine(doc, last).text.length);
        if (x < 0) x = 0;

        for (;;) {
            var lineObj = getLine(doc, lineNo);
            var found = coordsCharInner(cm, lineObj, lineNo, x, y);
            var merged = collapsedSpanAtEnd(lineObj);
            var mergedPos = merged && merged.find();
            if (merged && found.ch >= mergedPos.from.ch)
                lineNo = mergedPos.to.line;
            else
                return found;
        }
    }

    function coordsCharInner(cm, lineObj, lineNo, x, y) {
        var innerOff = y - heightAtLine(cm, lineObj);
        var wrongLine = false, cWidth = cm.display.wrapper.clientWidth;
        var measurement = measureLine(cm, lineObj);

        function getX(ch) {
            var sp = cursorCoords(cm, Pos(lineNo, ch), "line",
                lineObj, measurement);
            wrongLine = true;
            if (innerOff > sp.bottom) return Math.max(0, sp.left - cWidth);
            else if (innerOff < sp.top) return sp.left + cWidth;
            else wrongLine = false;
            return sp.left;
        }

        var bidi = getOrder(lineObj), dist = lineObj.text.length;
        var from = lineLeft(lineObj), to = lineRight(lineObj);
        var fromX = getX(from), fromOutside = wrongLine, toX = getX(to), toOutside = wrongLine;

        if (x > toX) return {line: lineNo, ch: to, outside: toOutside};
        // Do a binary search between these bounds.
        for (;;) {
            if (bidi ? to == from || to == moveVisually(lineObj, from, 1) : to - from <= 1) {
                var after = x - fromX < toX - x, ch = after ? from : to;
                while (isExtendingChar.test(lineObj.text.charAt(ch))) ++ch;
                return {line: lineNo, ch: ch, after: after, outside: after ? fromOutside : toOutside};
            }
            var step = Math.ceil(dist / 2), middle = from + step;
            if (bidi) {
                middle = from;
                for (var i = 0; i < step; ++i) middle = moveVisually(lineObj, middle, 1);
            }
            var middleX = getX(middle);
            if (middleX > x) {to = middle; toX = middleX; if (toOutside = wrongLine) toX += 1000; dist -= step;}
            else {from = middle; fromX = middleX; fromOutside = wrongLine; dist = step;}
        }
    }

    var measureText;
    function textHeight(display) {
        if (display.cachedTextHeight != null) return display.cachedTextHeight;
        if (measureText == null) {
            measureText = elt("pre");
            // Measure a bunch of lines, for browsers that compute
            // fractional heights.
            for (var i = 0; i < 49; ++i) {
                measureText.appendChild(document.createTextNode("x"));
                measureText.appendChild(elt("br"));
            }
            measureText.appendChild(document.createTextNode("x"));
        }
        removeChildrenAndAdd(display.measure, measureText);
        var height = measureText.offsetHeight / 50;
        if (height > 3) display.cachedTextHeight = height;
        removeChildren(display.measure);
        return height || 1;
    }

    function charWidth(display) {
        if (display.cachedCharWidth != null) return display.cachedCharWidth;
        var anchor = elt("span", "x");
        var pre = elt("pre", [anchor]);
        removeChildrenAndAdd(display.measure, pre);
        var width = anchor.offsetWidth;
        if (width > 2) display.cachedCharWidth = width;
        return width || 10;
    }

    // OPERATIONS

    // 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(cm) {
        cm.curOp = {
            // An array of ranges of lines that have to be updated. See
            // updateDisplay.
            changes: [],
            updateInput: null,
            userSelChange: null,
            textChanged: null,
            selectionChanged: false,
            updateMaxLine: false,
            updateScrollPos: false,
            id: ++cm.nextOpId
        };
        if (!delayedCallbackDepth++) delayedCallbacks = [];
    }

    function endOperation(cm) {
        var op = cm.curOp, doc = cm.doc, display = cm.display;
        cm.curOp = null;

        if (op.updateMaxLine) computeMaxLength(cm);
        if (display.maxLineChanged && !cm.options.lineWrapping) {
            var width = measureLine(cm, display.maxLine).width;
            display.sizer.style.minWidth = Math.max(0, width + 3 + scrollerCutOff) + "px";
            display.maxLineChanged = false;
            var maxScrollLeft = Math.max(0, display.sizer.offsetLeft + display.sizer.offsetWidth - display.scroller.clientWidth);
            if (maxScrollLeft < doc.scrollLeft && !op.updateScrollPos)
                setScrollLeft(cm, Math.min(display.scroller.scrollLeft, maxScrollLeft), true);
        }
        var newScrollPos, updated;
        if (op.updateScrollPos) {
            newScrollPos = op.updateScrollPos;
        } else if (op.selectionChanged) {
            var coords = cursorCoords(cm, doc.sel.head);
            newScrollPos = calculateScrollPos(cm, coords.left, coords.top, coords.left, coords.bottom);
        }
        if (op.changes.length || newScrollPos && newScrollPos.scrollTop != null)
            updated = updateDisplay(cm, op.changes, newScrollPos && newScrollPos.scrollTop);
        if (!updated && op.selectionChanged) updateSelection(cm);
        if (op.updateScrollPos) {
            display.scroller.scrollTop = display.scrollbarV.scrollTop = doc.scrollTop = newScrollPos.scrollTop;
            display.scroller.scrollLeft = display.scrollbarH.scrollLeft = doc.scrollLeft = newScrollPos.scrollLeft;
            alignHorizontally(cm);
        } else if (newScrollPos) {
            scrollCursorIntoView(cm);
        }
        if (op.selectionChanged) restartBlink(cm);

        if (cm.state.focused && op.updateInput)
            resetInput(cm, op.userSelChange);

        var hidden = op.maybeHiddenMarkers, unhidden = op.maybeUnhiddenMarkers;
        if (hidden) for (var i = 0; i < hidden.length; ++i)
            if (!hidden[i].lines.length) signal(hidden[i], "hide");
        if (unhidden) for (var i = 0; i < unhidden.length; ++i)
            if (unhidden[i].lines.length) signal(unhidden[i], "unhide");

        var delayed;
        if (!--delayedCallbackDepth) {
            delayed = delayedCallbacks;
            delayedCallbacks = null;
        }

        if (op.textChanged)
            signal(cm, "change", cm, op.textChanged);

        if (op.textChanged && op.onChange && instance)
            op.onChange(instance, op.textChanged);

        if (op.selectionChanged) signal(cm, "cursorActivity", cm);
        if (delayed) for (var i = 0; i < delayed.length; ++i) delayed[i]();
    }

    // Wraps a function in an operation. Returns the wrapped function.
    function operation(cm1, f) {
        return function() {
            var cm = cm1 || this, withOp = !cm.curOp;
            if (withOp) startOperation(cm);
            try { var result = f.apply(cm, arguments); }
            finally { if (withOp) endOperation(cm); }
            return result;
        };
    }
    function docOperation(f) {
        return function() {
            var withOp = this.cm && !this.cm.curOp, result;
            if (withOp) startOperation(this.cm);
            try { result = f.apply(this, arguments); }
            finally { if (withOp) endOperation(this.cm); }
            return result;
        };
    }
    function runInOp(cm, f) {
        var withOp = !cm.curOp, result;
        if (withOp) startOperation(cm);
        try { result = f(); }
        finally { if (withOp) endOperation(cm); }
        return result;
    }

    function regChange(cm, from, to, lendiff) {
        if (from == null) from = cm.doc.first;
        if (to == null) to = cm.doc.first + cm.doc.size;
        cm.curOp.changes.push({from: from, to: to, diff: lendiff});
    }

    // INPUT HANDLING

    function slowPoll(cm) {
        if (cm.display.pollingFast) return;
        cm.display.poll.set(cm.options.pollInterval, function() {
            readInput(cm);
            if (cm.state.focused) slowPoll(cm);
        });
    }

    function fastPoll(cm) {
        var missed = false;
        cm.display.pollingFast = true;
        function p() {
            var changed = readInput(cm);
            if (!changed && !missed) {missed = true; cm.display.poll.set(60, p);}
            else {cm.display.pollingFast = false; slowPoll(cm);}
        }
        cm.display.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.)
    function readInput(cm) {
        var input = cm.display.input, prevInput = cm.display.prevInput, doc = cm.doc, sel = doc.sel;
        if (!cm.state.focused || hasSelection(input) || isReadOnly(cm)) return false;
        var text = input.value;
        if (text == prevInput && posEq(sel.from, sel.to)) return false;
        // IE enjoys randomly deselecting our input's text when
        // re-focusing. If the selection is gone but the cursor is at the
        // start of the input, that's probably what happened.
        if (ie && text && input.selectionStart === 0) {
            resetInput(cm, true);
            return false;
        }
        var withOp = !cm.curOp;
        if (withOp) startOperation(cm);
        sel.shift = false;
        var same = 0, l = Math.min(prevInput.length, text.length);
        while (same < l && prevInput[same] == text[same]) ++same;
        var from = sel.from, to = sel.to;
        if (same < prevInput.length)
            from = Pos(from.line, from.ch - (prevInput.length - same));
        else if (cm.state.overwrite && posEq(from, to) && !cm.state.pasteIncoming)
            to = Pos(to.line, Math.min(getLine(doc, to.line).text.length, to.ch + (text.length - same)));
        var updateInput = cm.curOp.updateInput;
        makeChange(cm.doc, {from: from, to: to, text: splitLines(text.slice(same)),
            origin: cm.state.pasteIncoming ? "paste" : "+input"}, "end");

        cm.curOp.updateInput = updateInput;
        if (text.length > 1000) input.value = cm.display.prevInput = "";
        else cm.display.prevInput = text;
        if (withOp) endOperation(cm);
        cm.state.pasteIncoming = false;
        return true;
    }

    function resetInput(cm, user) {
        var minimal, selected, doc = cm.doc;
        if (!posEq(doc.sel.from, doc.sel.to)) {
            cm.display.prevInput = "";
            minimal = hasCopyEvent &&
                (doc.sel.to.line - doc.sel.from.line > 100 || (selected = cm.getSelection()).length > 1000);
            if (minimal) cm.display.input.value = "-";
            else cm.display.input.value = selected || cm.getSelection();
            if (cm.state.focused) selectInput(cm.display.input);
        } else if (user) cm.display.prevInput = cm.display.input.value = "";
        cm.display.inaccurateSelection = minimal;
    }

    function focusInput(cm) {
        if (cm.options.readOnly != "nocursor" && (!mobile || document.activeElement != cm.display.input))
            cm.display.input.focus();
    }

    function isReadOnly(cm) {
        return cm.options.readOnly || cm.doc.cantEdit;
    }

    // EVENT HANDLERS

    function registerEventHandlers(cm) {
        var d = cm.display;
        on(d.scroller, "mousedown", operation(cm, onMouseDown));
        on(d.scroller, "dblclick", operation(cm, e_preventDefault));
        on(d.lineSpace, "selectstart", function(e) {
            if (!eventInWidget(d, e)) e_preventDefault(e);
        });
        // 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 (!captureMiddleClick) on(d.scroller, "contextmenu", function(e) {onContextMenu(cm, e);});

        on(d.scroller, "scroll", function() {
            setScrollTop(cm, d.scroller.scrollTop);
            setScrollLeft(cm, d.scroller.scrollLeft, true);
            signal(cm, "scroll", cm);
        });
        on(d.scrollbarV, "scroll", function() {
            setScrollTop(cm, d.scrollbarV.scrollTop);
        });
        on(d.scrollbarH, "scroll", function() {
            setScrollLeft(cm, d.scrollbarH.scrollLeft);
        });

        on(d.scroller, "mousewheel", function(e){onScrollWheel(cm, e);});
        on(d.scroller, "DOMMouseScroll", function(e){onScrollWheel(cm, e);});

        function reFocus() { if (cm.state.focused) setTimeout(bind(focusInput, cm), 0); }
        on(d.scrollbarH, "mousedown", reFocus);
        on(d.scrollbarV, "mousedown", reFocus);
        // Prevent wrapper from ever scrolling
        on(d.wrapper, "scroll", function() { d.wrapper.scrollTop = d.wrapper.scrollLeft = 0; });

        function onResize() {
            // Might be a text scaling operation, clear size caches.
            d.cachedCharWidth = d.cachedTextHeight = null;
            clearCaches(cm);
            runInOp(cm, bind(regChange, cm));
        }
        on(window, "resize", onResize);
        // Above handler holds on to the editor and its data structures.
        // Here we poll to unregister it when the editor is no longer in
        // the document, so that it can be garbage-collected.
        function unregister() {
            for (var p = d.wrapper.parentNode; p && p != document.body; p = p.parentNode) {}
            if (p) setTimeout(unregister, 5000);
            else off(window, "resize", onResize);
        }
        setTimeout(unregister, 5000);

        on(d.input, "keyup", operation(cm, function(e) {
            if (cm.options.onKeyEvent && cm.options.onKeyEvent(cm, addStop(e))) return;
            if (e_prop(e, "keyCode") == 16) cm.doc.sel.shift = false;
        }));
        on(d.input, "input", bind(fastPoll, cm));
        on(d.input, "keydown", operation(cm, onKeyDown));
        on(d.input, "keypress", operation(cm, onKeyPress));
        on(d.input, "focus", bind(onFocus, cm));
        on(d.input, "blur", bind(onBlur, cm));

        function drag_(e) {
            if (cm.options.onDragEvent && cm.options.onDragEvent(cm, addStop(e))) return;
            e_stop(e);
        }
        if (cm.options.dragDrop) {
            on(d.scroller, "dragstart", function(e){onDragStart(cm, e);});
            on(d.scroller, "dragenter", drag_);
            on(d.scroller, "dragover", drag_);
            on(d.scroller, "drop", operation(cm, onDrop));
        }
        on(d.scroller, "paste", function(e){
            if (eventInWidget(d, e)) return;
            focusInput(cm);
            fastPoll(cm);
        });
        on(d.input, "paste", function() {
            cm.state.pasteIncoming = true;
            fastPoll(cm);
        });

        function prepareCopy() {
            if (d.inaccurateSelection) {
                d.prevInput = "";
                d.inaccurateSelection = false;
                d.input.value = cm.getSelection();
                selectInput(d.input);
            }
        }
        on(d.input, "cut", prepareCopy);
        on(d.input, "copy", prepareCopy);

        // Needed to handle Tab key in KHTML
        if (khtml) on(d.sizer, "mouseup", function() {
            if (document.activeElement == d.input) d.input.blur();
            focusInput(cm);
        });
    }

    function eventInWidget(display, e) {
        for (var n = e_target(e); n != display.wrapper; n = n.parentNode) {
            if (!n) return true;
            if (/\bCodeMirror-(?:line)?widget\b/.test(n.className) ||
                n.parentNode == display.sizer && n != display.mover) return true;
        }
    }

    function posFromMouse(cm, e, liberal) {
        var display = cm.display;
        if (!liberal) {
            var target = e_target(e);
            if (target == display.scrollbarH || target == display.scrollbarH.firstChild ||
                target == display.scrollbarV || target == display.scrollbarV.firstChild ||
                target == display.scrollbarFiller) return null;
        }
        var x, y, space = getPixelRect(display.lineSpace);
        // Fails unpredictably on IE[67] when mouse is dragged around quickly.
        try { x = e.clientX; y = e.clientY; } catch (e) { return null; }
        return coordsChar(cm, x - space.left, y - space.top);
    }

    var lastClick, lastDoubleClick;
    function onMouseDown(e) {
        var cm = this, display = cm.display, doc = cm.doc, sel = doc.sel;
        sel.shift = e_prop(e, "shiftKey");

        if (eventInWidget(display, e)) {
            if (!webkit) {
                display.scroller.draggable = false;
                setTimeout(function(){display.scroller.draggable = true;}, 100);
            }
            return;
        }
        if (clickInGutter(cm, e)) return;
        var start = posFromMouse(cm, e);

        switch (e_button(e)) {
            case 3:
                if (captureMiddleClick) onContextMenu.call(cm, cm, e);
                return;
            case 2:
                if (start) extendSelection(cm.doc, start);
                setTimeout(bind(focusInput, cm), 20);
                e_preventDefault(e);
                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) == display.scroller) e_preventDefault(e); return;}

        if (!cm.state.focused) onFocus(cm);

        var now = +new Date, type = "single";
        if (lastDoubleClick && lastDoubleClick.time > now - 400 && posEq(lastDoubleClick.pos, start)) {
            type = "triple";
            e_preventDefault(e);
            setTimeout(bind(focusInput, cm), 20);
            selectLine(cm, start.line);
        } else if (lastClick && lastClick.time > now - 400 && posEq(lastClick.pos, start)) {
            type = "double";
            lastDoubleClick = {time: now, pos: start};
            e_preventDefault(e);
            var word = findWordAt(getLine(doc, start.line).text, start);
            extendSelection(cm.doc, word.from, word.to);
        } else { lastClick = {time: now, pos: start}; }

        var last = start;
        if (cm.options.dragDrop && dragAndDrop && !isReadOnly(cm) && !posEq(sel.from, sel.to) &&
            !posLess(start, sel.from) && !posLess(sel.to, start) && type == "single") {
            var dragEnd = operation(cm, function(e2) {
                if (webkit) display.scroller.draggable = false;
                cm.state.draggingText = false;
                off(document, "mouseup", dragEnd);
                off(display.scroller, "drop", dragEnd);
                if (Math.abs(e.clientX - e2.clientX) + Math.abs(e.clientY - e2.clientY) < 10) {
                    e_preventDefault(e2);
                    extendSelection(cm.doc, start);
                    focusInput(cm);
                }
            });
            // Let the drag handler handle this.
            if (webkit) display.scroller.draggable = true;
            cm.state.draggingText = dragEnd;
            // IE's approach to draggable
            if (display.scroller.dragDrop) display.scroller.dragDrop();
            on(document, "mouseup", dragEnd);
            on(display.scroller, "drop", dragEnd);
            return;
        }
        e_preventDefault(e);
        if (type == "single") extendSelection(cm.doc, clipPos(doc, start));

        var startstart = sel.from, startend = sel.to;

        function doSelect(cur) {
            if (type == "single") {
                extendSelection(cm.doc, clipPos(doc, start), cur);
                return;
            }

            startstart = clipPos(doc, startstart);
            startend = clipPos(doc, startend);
            if (type == "double") {
                var word = findWordAt(getLine(doc, cur.line).text, cur);
                if (posLess(cur, startstart)) extendSelection(cm.doc, word.from, startend);
                else extendSelection(cm.doc, startstart, word.to);
            } else if (type == "triple") {
                if (posLess(cur, startstart)) extendSelection(cm.doc, startend, clipPos(doc, Pos(cur.line, 0)));
                else extendSelection(cm.doc, startstart, clipPos(doc, Pos(cur.line + 1, 0)));
            }
        }

        var editorSize = getPixelRect(display.wrapper);
        // Used to ensure timeout re-tries don't fire when another extend
        // happened in the meantime (clearTimeout isn't reliable -- at
        // least on Chrome, the timeouts still happen even when cleared,
        // if the clear happens after their scheduled firing time).
        var counter = 0;

        function extend(e) {
            var curCount = ++counter;
            var cur = posFromMouse(cm, e, true);
            if (!cur) return;
            if (!posEq(cur, last)) {
                if (!cm.state.focused) onFocus(cm);
                last = cur;
                doSelect(cur);
                var visible = visibleLines(display, doc);
                if (cur.line >= visible.to || cur.line < visible.from)
                    setTimeout(operation(cm, function(){if (counter == curCount) extend(e);}), 150);
            } else {
                var outside = e.clientY < editorSize.top ? -20 : e.clientY > editorSize.bottom ? 20 : 0;
                if (outside) setTimeout(operation(cm, function() {
                    if (counter != curCount) return;
                    display.scroller.scrollTop += outside;
                    extend(e);
                }), 50);
            }
        }

        function done(e) {
            counter = Infinity;
            var cur = posFromMouse(cm, e);
            if (cur) doSelect(cur);
            e_preventDefault(e);
            focusInput(cm);
            off(document, "mousemove", move);
            off(document, "mouseup", up);
        }

        var move = operation(cm, function(e) {
            if (!ie && !e_button(e)) done(e);
            else extend(e);
        });
        var up = operation(cm, done);
        on(document, "mousemove", move);
        on(document, "mouseup", up);
    }

    function onDrop(e) {
        var cm = this;
        if (eventInWidget(cm.display, e) || (cm.options.onDragEvent && cm.options.onDragEvent(cm, addStop(e))))
            return;
        e_preventDefault(e);
        var pos = posFromMouse(cm, e, true), files = e.dataTransfer.files;
        if (!pos || isReadOnly(cm)) return;
        if (files && files.length && window.FileReader && window.File) {
            var n = files.length, text = Array(n), read = 0;
            var loadFile = function(file, i) {
                var reader = new FileReader;
                reader.onload = function() {
                    text[i] = reader.result;
                    if (++read == n) {
                        pos = clipPos(cm.doc, pos);
                        replaceRange(cm.doc, text.join(""), pos, "around", "paste");
                    }
                };
                reader.readAsText(file);
            };
            for (var i = 0; i < n; ++i) loadFile(files[i], i);
        } else {
            // Don't do a replace if the drop happened inside of the selected text.
            if (cm.state.draggingText && !(posLess(pos, cm.doc.sel.from) || posLess(cm.doc.sel.to, pos))) {
                cm.state.draggingText(e);
                // Ensure the editor is re-focused
                setTimeout(bind(focusInput, cm), 20);
                return;
            }
            try {
                var text = e.dataTransfer.getData("Text");
                if (text) {
                    var curFrom = cm.doc.sel.from, curTo = cm.doc.sel.to;
                    setSelection(cm.doc, pos, pos);
                    if (cm.state.draggingText) replaceRange(cm.doc, "", curFrom, curTo, "paste");
                    cm.replaceSelection(text, null, "paste");
                    focusInput(cm);
                    onFocus(cm);
                }
            }
            catch(e){}
        }
    }

    function clickInGutter(cm, e) {
        var display = cm.display;
        try { var mX = e.clientX, mY = e.clientY; }
        catch(e) { return false; }

        if (mX >= Math.floor(getPixelRect(display.gutters).right)) return false;
        e_preventDefault(e);
        if (!hasHandler(cm, "gutterClick")) return true;

        var lineBox = getPixelRect(display.lineDiv);
        if (mY > lineBox.bottom) return true;
        mY -= lineBox.top - display.viewOffset;

        for (var i = 0; i < cm.options.gutters.length; ++i) {
            var g = display.gutters.childNodes[i];
            if (g && getPixelRect(g).right >= mX) {
                var line = lineAtHeight(cm.doc, mY);
                var gutter = cm.options.gutters[i];
                signalLater(cm, "gutterClick", cm, line, gutter, e);
                break;
            }
        }
        return true;
    }

    function onDragStart(cm, e) {
        if (eventInWidget(cm.display, e)) return;

        var txt = cm.getSelection();
        e.dataTransfer.setData("Text", txt);

        // Use dummy image instead of default browsers image.
        // Recent Safari (~6.0.2) have a tendency to segfault when this happens, so we don't do it there.
        if (e.dataTransfer.setDragImage && !safari) {
            var img = elt("img", null, null, "position: fixed; left: 0; top: 0;");
            if (opera) {
                img.width = img.height = 1;
                cm.display.wrapper.appendChild(img);
                // Force a relayout, or Opera won't use our image for some obscure reason
                img._top = img.offsetTop;
            }
            e.dataTransfer.setDragImage(img, 0, 0);
            if (opera) img.parentNode.removeChild(img);
        }
    }

    function setScrollTop(cm, val) {
        if (Math.abs(cm.doc.scrollTop - val) < 2) return;
        cm.doc.scrollTop = val;
        if (!gecko) updateDisplay(cm, [], val);
        if (cm.display.scroller.scrollTop != val) cm.display.scroller.scrollTop = val;
        if (cm.display.scrollbarV.scrollTop != val) cm.display.scrollbarV.scrollTop = val;
        if (gecko) updateDisplay(cm, []);
    }
    function setScrollLeft(cm, val, isScroller) {
        if (isScroller ? val == cm.doc.scrollLeft : Math.abs(cm.doc.scrollLeft - val) < 2) return;
        val = Math.min(val, cm.display.scroller.scrollWidth - cm.display.scroller.clientWidth);
        cm.doc.scrollLeft = val;
        alignHorizontally(cm);
        if (cm.display.scroller.scrollLeft != val) cm.display.scroller.scrollLeft = val;
        if (cm.display.scrollbarH.scrollLeft != val) cm.display.scrollbarH.scrollLeft = val;
    }

    // Since the delta values reported on mouse wheel events are
    // unstandardized between browsers and even browser versions, and
    // generally horribly unpredictable, this code starts by measuring
    // the scroll effect that the first few mouse wheel events have,
    // and, from that, detects the way it can convert deltas to pixel
    // offsets afterwards.
    //
    // The reason we want to know the amount a wheel event will scroll
    // is that it gives us a chance to update the display before the
    // actual scrolling happens, reducing flickering.

    var wheelSamples = 0, wheelPixelsPerUnit = null;
    // Fill in a browser-detected starting value on browsers where we
    // know one. These don't have to be accurate -- the result of them
    // being wrong would just be a slight flicker on the first wheel
    // scroll (if it is large enough).
    if (ie) wheelPixelsPerUnit = -.53;
    else if (gecko) wheelPixelsPerUnit = 15;
    else if (chrome) wheelPixelsPerUnit = -.7;
    else if (safari) wheelPixelsPerUnit = -1/3;

    function onScrollWheel(cm, e) {
        var dx = e.wheelDeltaX, dy = e.wheelDeltaY;
        if (dx == null && e.detail && e.axis == e.HORIZONTAL_AXIS) dx = e.detail;
        if (dy == null && e.detail && e.axis == e.VERTICAL_AXIS) dy = e.detail;
        else if (dy == null) dy = e.wheelDelta;

        // Webkit browsers on OS X abort momentum scrolls when the target
        // of the scroll event is removed from the scrollable element.
        // This hack (see related code in patchDisplay) makes sure the
        // element is kept around.
        if (dy && mac && webkit) {
            for (var cur = e.target; cur != scroll; cur = cur.parentNode) {
                if (cur.lineObj) {
                    cm.display.currentWheelTarget = cur;
                    break;
                }
            }
        }

        var display = cm.display, scroll = display.scroller;
        // On some browsers, horizontal scrolling will cause redraws to
        // happen before the gutter has been realigned, causing it to
        // wriggle around in a most unseemly way. When we have an
        // estimated pixels/delta value, we just handle horizontal
        // scrolling entirely here. It'll be slightly off from native, but
        // better than glitching out.
        if (dx && !gecko && !opera && wheelPixelsPerUnit != null) {
            if (dy)
                setScrollTop(cm, Math.max(0, Math.min(scroll.scrollTop + dy * wheelPixelsPerUnit, scroll.scrollHeight - scroll.clientHeight)));
            setScrollLeft(cm, Math.max(0, Math.min(scroll.scrollLeft + dx * wheelPixelsPerUnit, scroll.scrollWidth - scroll.clientWidth)));
            e_preventDefault(e);
            display.wheelStartX = null; // Abort measurement, if in progress
            return;
        }

        if (dy && wheelPixelsPerUnit != null) {
            var pixels = dy * wheelPixelsPerUnit;
            var top = cm.doc.scrollTop, bot = top + display.wrapper.clientHeight;
            if (pixels < 0) top = Math.max(0, top + pixels - 50);
            else bot = Math.min(cm.doc.height, bot + pixels + 50);
            updateDisplay(cm, [], {top: top, bottom: bot});
        }

        if (wheelSamples < 20) {
            if (display.wheelStartX == null) {
                display.wheelStartX = scroll.scrollLeft; display.wheelStartY = scroll.scrollTop;
                display.wheelDX = dx; display.wheelDY = dy;
                setTimeout(function() {
                    if (display.wheelStartX == null) return;
                    var movedX = scroll.scrollLeft - display.wheelStartX;
                    var movedY = scroll.scrollTop - display.wheelStartY;
                    var sample = (movedY && display.wheelDY && movedY / display.wheelDY) ||
                        (movedX && display.wheelDX && movedX / display.wheelDX);
                    display.wheelStartX = display.wheelStartY = null;
                    if (!sample) return;
                    wheelPixelsPerUnit = (wheelPixelsPerUnit * wheelSamples + sample) / (wheelSamples + 1);
                    ++wheelSamples;
                }, 200);
            } else {
                display.wheelDX += dx; display.wheelDY += dy;
            }
        }
    }

    function doHandleBinding(cm, bound, dropShift) {
        if (typeof bound == "string") {
            bound = commands[bound];
            if (!bound) return false;
        }
        // Ensure previous input has been read, so that the handler sees a
        // consistent view of the document
        if (cm.display.pollingFast && readInput(cm)) cm.display.pollingFast = false;
        var doc = cm.doc, prevShift = doc.sel.shift, done = false;
        try {
            if (isReadOnly(cm)) cm.state.suppressEdits = true;
            if (dropShift) doc.sel.shift = false;
            done = bound(cm) != Pass;
        } finally {
            doc.sel.shift = prevShift;
            cm.state.suppressEdits = false;
        }
        return done;
    }

    function allKeyMaps(cm) {
        var maps = cm.state.keyMaps.slice(0);
        maps.push(cm.options.keyMap);
        if (cm.options.extraKeys) maps.unshift(cm.options.extraKeys);
        return maps;
    }

    var maybeTransition;
    function handleKeyBinding(cm, e) {
        // Handle auto keymap transitions
        var startMap = getKeyMap(cm.options.keyMap), next = startMap.auto;
        clearTimeout(maybeTransition);
        if (next && !isModifierKey(e)) maybeTransition = setTimeout(function() {
            if (getKeyMap(cm.options.keyMap) == startMap)
                cm.options.keyMap = (next.call ? next.call(null, cm) : next);
        }, 50);

        var name = keyName(e, true), handled = false;
        if (!name) return false;
        var keymaps = allKeyMaps(cm);

        if (e_prop(e, "shiftKey")) {
            // First try to resolve full name (including 'Shift-'). Failing
            // that, see if there is a cursor-motion command (starting with
            // 'go') bound to the keyname without 'Shift-'.
            handled = lookupKey("Shift-" + name, keymaps, function(b) {return doHandleBinding(cm, b, true);})
                || lookupKey(name, keymaps, function(b) {
                if (typeof b == "string" && /^go[A-Z]/.test(b)) return doHandleBinding(cm, b);
            });
        } else {
            handled = lookupKey(name, keymaps, function(b) { return doHandleBinding(cm, b); });
        }
        if (handled == "stop") handled = false;

        if (handled) {
            e_preventDefault(e);
            restartBlink(cm);
            if (ie_lt9) { e.oldKeyCode = e.keyCode; e.keyCode = 0; }
        }
        return handled;
    }

    function handleCharBinding(cm, e, ch) {
        var handled = lookupKey("'" + ch + "'", allKeyMaps(cm),
            function(b) { return doHandleBinding(cm, b, true); });
        if (handled) {
            e_preventDefault(e);
            restartBlink(cm);
        }
        return handled;
    }

    var lastStoppedKey = null;
    function onKeyDown(e) {
        var cm = this;
        if (!cm.state.focused) onFocus(cm);
        if (ie && e.keyCode == 27) { e.returnValue = false; }
        if (cm.options.onKeyEvent && cm.options.onKeyEvent(cm, addStop(e))) return;
        var code = e_prop(e, "keyCode");
        // IE does strange things with escape.
        cm.doc.sel.shift = code == 16 || e_prop(e, "shiftKey");
        // First give onKeyEvent option a chance to handle this.
        var handled = handleKeyBinding(cm, e);
        if (opera) {
            lastStoppedKey = handled ? code : null;
            // Opera has no cut event... we try to at least catch the key combo
            if (!handled && code == 88 && !hasCopyEvent && e_prop(e, mac ? "metaKey" : "ctrlKey"))
                cm.replaceSelection("");
        }
    }

    function onKeyPress(e) {
        var cm = this;
        if (cm.options.onKeyEvent && cm.options.onKeyEvent(cm, addStop(e))) return;
        var keyCode = e_prop(e, "keyCode"), charCode = e_prop(e, "charCode");
        if (opera && keyCode == lastStoppedKey) {lastStoppedKey = null; e_preventDefault(e); return;}
        if (((opera && (!e.which || e.which < 10)) || khtml) && handleKeyBinding(cm, e)) return;
        var ch = String.fromCharCode(charCode == null ? keyCode : charCode);
        if (this.options.electricChars && this.doc.mode.electricChars &&
            this.options.smartIndent && !isReadOnly(this) &&
            this.doc.mode.electricChars.indexOf(ch) > -1)
            setTimeout(operation(cm, function() {indentLine(cm, cm.doc.sel.to.line, "smart");}), 75);
        if (handleCharBinding(cm, e, ch)) return;
        fastPoll(cm);
    }

    function onFocus(cm) {
        if (cm.options.readOnly == "nocursor") return;
        if (!cm.state.focused) {
            signal(cm, "focus", cm);
            cm.state.focused = true;
            if (cm.display.wrapper.className.search(/\bCodeMirror-focused\b/) == -1)
                cm.display.wrapper.className += " CodeMirror-focused";
            resetInput(cm, true);
        }
        slowPoll(cm);
        restartBlink(cm);
    }
    function onBlur(cm) {
        if (cm.state.focused) {
            signal(cm, "blur", cm);
            cm.state.focused = false;
            cm.display.wrapper.className = cm.display.wrapper.className.replace(" CodeMirror-focused", "");
        }
        clearInterval(cm.display.blinker);
        setTimeout(function() {if (!cm.state.focused) cm.doc.sel.shift = false;}, 150);
    }

    var detectingSelectAll;
    function onContextMenu(cm, e) {
        var display = cm.display, sel = cm.doc.sel;
        if (eventInWidget(display, e)) return;

        var pos = posFromMouse(cm, e), scrollPos = display.scroller.scrollTop;
        if (!pos || opera) return; // Opera is difficult.
        if (posEq(sel.from, sel.to) || posLess(pos, sel.from) || !posLess(pos, sel.to))
            operation(cm, setSelection)(cm.doc, pos, pos);

        var oldCSS = display.input.style.cssText;
        display.inputDiv.style.position = "absolute";
        display.input.style.cssText = "position: fixed; width: 30px; height: 30px; top: " + (e.clientY - 5) +
            "px; left: " + (e.clientX - 5) + "px; z-index: 1000; background: white; outline: none;" +
            "border-width: 0; outline: none; overflow: hidden; opacity: .05; -ms-opacity: .05; filter: alpha(opacity=5);";
        focusInput(cm);
        resetInput(cm, true);
        // Adds "Select all" to context menu in FF
        if (posEq(sel.from, sel.to)) display.input.value = display.prevInput = " ";

        function rehide() {
            display.inputDiv.style.position = "relative";
            display.input.style.cssText = oldCSS;
            if (ie_lt9) display.scrollbarV.scrollTop = display.scroller.scrollTop = scrollPos;
            slowPoll(cm);

            // Try to detect the user choosing select-all 
            if (display.input.selectionStart != null && (!ie || ie_lt9)) {
                clearTimeout(detectingSelectAll);
                var extval = display.input.value = " " + (posEq(sel.from, sel.to) ? "" : display.input.value), i = 0;
                display.prevInput = " ";
                display.input.selectionStart = 1; display.input.selectionEnd = extval.length;
                var poll = function(){
                    if (display.prevInput == " " && display.input.selectionStart == 0)
                        operation(cm, commands.selectAll)(cm);
                    else if (i++ < 10) detectingSelectAll = setTimeout(poll, 500);
                    else resetInput(cm);
                };
                detectingSelectAll = setTimeout(poll, 200);
            }
        }

        if (captureMiddleClick) {
            e_stop(e);
            var mouseup = function() {
                off(window, "mouseup", mouseup);
                setTimeout(rehide, 20);
            };
            on(window, "mouseup", mouseup);
        } else {
            setTimeout(rehide, 50);
        }
    }

    // UPDATING

    function changeEnd(change) {
        return Pos(change.from.line + change.text.length - 1,
            lst(change.text).length + (change.text.length == 1 ? change.from.ch : 0));
    }

    // Hint can be null|"end"|"start"|"around"|{anchor,head}
    function computeSelAfterChange(sel, change, hint) {
        if (hint && typeof hint == "object") return hint; // Assumed to be {from, to} object
        if (hint == "start") return {anchor: change.from, head: change.from};

        var end = changeEnd(change);
        if (hint == "around") return {anchor: change.from, head: end};
        if (hint == "end") return {anchor: end, head: end};

        // hint is null, leave the selection alone as much as possible
        var adjustPos = function(pos) {
            if (posLess(pos, change.from)) return pos;
            if (!posLess(change.to, pos)) return end;

            var line = pos.line + change.text.length - (change.to.line - change.from.line) - 1, ch = pos.ch;
            if (pos.line == change.to.line) ch += end.ch - change.to.ch;
            return Pos(line, ch);
        };
        return {anchor: adjustPos(sel.anchor), head: adjustPos(sel.head)};
    }

    // Replace the range from from to to by the strings in replacement.
    // change is a {from, to, text [, origin]} object
    function makeChange(doc, change, selUpdate, ignoreReadOnly) {
        if (doc.cm) {
            if (!doc.cm.curOp) return operation(doc.cm, makeChange)(doc, change, selUpdate, ignoreReadOnly);
            if (doc.cm.state.suppressEdits) return;
        }

        // Possibly split or suppress the update based on the presence
        // of read-only spans in its range.
        var split = sawReadOnlySpans && !ignoreReadOnly && removeReadOnlyRanges(doc, change.from, change.to);
        if (split) {
            for (var i = split.length - 1; i >= 1; --i)
                makeChangeNoReadonly(doc, {from: split[i].from, to: split[i].to, text: [""]});
            if (split.length)
                makeChangeNoReadonly(doc, {from: split[0].from, to: split[0].to, text: change.text}, selUpdate);
        } else {
            makeChangeNoReadonly(doc, change, selUpdate);
        }
    }

    function makeChangeNoReadonly(doc, change, selUpdate) {
        var selAfter = computeSelAfterChange(doc.sel, change, selUpdate);
        addToHistory(doc, change, selAfter, doc.cm ? doc.cm.curOp.id : NaN);

        makeChangeSingleDoc(doc, change, selAfter, stretchSpansOverChange(doc, change));
        var rebased = [];

        linkedDocs(doc, function(doc, sharedHist) {
            if (!sharedHist && indexOf(rebased, doc.history) == -1) {
                rebaseHist(doc.history, change);
                rebased.push(doc.history);
            }
            makeChangeSingleDoc(doc, change, null, stretchSpansOverChange(doc, change));
        });
    }

    function makeChangeFromHistory(doc, type) {
        var hist = doc.history;
        var event = (type == "undo" ? hist.done : hist.undone).pop();
        if (!event) return;
        hist.dirtyCounter += type == "undo" ? -1 : 1;

        var anti = {changes: [], anchorBefore: event.anchorAfter, headBefore: event.headAfter,
            anchorAfter: event.anchorBefore, headAfter: event.headBefore};
        (type == "undo" ? hist.undone : hist.done).push(anti);

        for (var i = event.changes.length - 1; i >= 0; --i) {
            var change = event.changes[i];
            change.origin = type;
            anti.changes.push(historyChangeFromChange(doc, change));

            var after = i ? computeSelAfterChange(doc.sel, change, null)
                : {anchor: event.anchorBefore, head: event.headBefore};
            makeChangeSingleDoc(doc, change, after, mergeOldSpans(doc, change));
            var rebased = [];

            linkedDocs(doc, function(doc, sharedHist) {
                if (!sharedHist && indexOf(rebased, doc.history) == -1) {
                    rebaseHist(doc.history, change);
                    rebased.push(doc.history);
                }
                makeChangeSingleDoc(doc, change, null, mergeOldSpans(doc, change));
            });
        }
    }

    function shiftDoc(doc, distance) {
        function shiftPos(pos) {return Pos(pos.line + distance, pos.ch);}
        doc.first += distance;
        if (doc.cm) regChange(doc.cm, doc.first, doc.first, distance);
        doc.sel.head = shiftPos(doc.sel.head); doc.sel.anchor = shiftPos(doc.sel.anchor);
        doc.sel.from = shiftPos(doc.sel.from); doc.sel.to = shiftPos(doc.sel.to);
    }

    function makeChangeSingleDoc(doc, change, selAfter, spans) {
        if (doc.cm && !doc.cm.curOp)
            return operation(doc.cm, makeChangeSingleDoc)(doc, change, selAfter, spans);

        if (change.to.line < doc.first) {
            shiftDoc(doc, change.text.length - 1 - (change.to.line - change.from.line));
            return;
        }
        if (change.from.line > doc.lastLine()) return;

        // Clip the change to the size of this doc
        if (change.from.line < doc.first) {
            var shift = change.text.length - 1 - (doc.first - change.from.line);
            shiftDoc(doc, shift);
            change = {from: Pos(doc.first, 0), to: Pos(change.to.line + shift, change.to.ch),
                text: [lst(change.text)], origin: change.origin};
        }
        var last = doc.lastLine();
        if (change.to.line > last) {
            change = {from: change.from, to: Pos(last, getLine(doc, last).text.length),
                text: [change.text[0]], origin: change.origin};
        }

        if (!selAfter) selAfter = computeSelAfterChange(doc.sel, change, null);
        if (doc.cm) makeChangeSingleDocInEditor(doc.cm, change, spans, selAfter);
        else updateDoc(doc, change, spans, selAfter);
    }

    function makeChangeSingleDocInEditor(cm, change, spans, selAfter) {
        var doc = cm.doc, display = cm.display, from = change.from, to = change.to;

        var recomputeMaxLength = false, checkWidthStart = from.line;
        if (!cm.options.lineWrapping) {
            checkWidthStart = lineNo(visualLine(doc, getLine(doc, from.line)));
            doc.iter(checkWidthStart, to.line + 1, function(line) {
                if (line == display.maxLine) {
                    recomputeMaxLength = true;
                    return true;
                }
            });
        }

        updateDoc(doc, change, spans, selAfter, estimateHeight(cm));

        if (!cm.options.lineWrapping) {
            doc.iter(checkWidthStart, from.line + change.text.length, function(line) {
                var len = lineLength(doc, line);
                if (len > display.maxLineLength) {
                    display.maxLine = line;
                    display.maxLineLength = len;
                    display.maxLineChanged = true;
                    recomputeMaxLength = false;
                }
            });
            if (recomputeMaxLength) cm.curOp.updateMaxLine = true;
        }

        // Adjust frontier, schedule worker
        doc.frontier = Math.min(doc.frontier, from.line);
        startWorker(cm, 400);

        var lendiff = change.text.length - (to.line - from.line) - 1;
        // Remember that these lines changed, for updating the display
        regChange(cm, from.line, to.line + 1, lendiff);
        if (hasHandler(cm, "change")) {
            var changeObj = {from: from, to: to, text: change.text, origin: change.origin};
            if (cm.curOp.textChanged) {
                for (var cur = cm.curOp.textChanged; cur.next; cur = cur.next) {}
                cur.next = changeObj;
            } else cm.curOp.textChanged = changeObj;
        }
    }

    function replaceRange(doc, code, from, to, origin) {
        if (!to) to = from;
        if (posLess(to, from)) { var tmp = to; to = from; from = tmp; }
        if (typeof code == "string") code = splitLines(code);
        makeChange(doc, {from: from, to: to, text: code, origin: origin}, null);
    }

    // POSITION OBJECT

    function Pos(line, ch) {
        if (!(this instanceof Pos)) return new Pos(line, ch);
        this.line = line; this.ch = ch;
    }
    CodeMirror.Pos = Pos;

    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 Pos(x.line, x.ch);}

    // SELECTION

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

    // If shift is held, this will move the selection anchor. Otherwise,
    // it'll set the whole selection.
    function extendSelection(doc, pos, other, bias) {
        if (doc.sel.shift || doc.sel.extend) {
            var anchor = doc.sel.anchor;
            if (other) {
                var posBefore = posLess(pos, anchor);
                if (posBefore != posLess(other, anchor)) {
                    anchor = pos;
                    pos = other;
                } else if (posBefore != posLess(pos, other)) {
                    pos = other;
                }
            }
            setSelection(doc, anchor, pos, bias);
        } else {
            setSelection(doc, pos, other || pos, bias);
        }
        if (doc.cm) doc.cm.curOp.userSelChange = true;
    }

    // Update the selection. Last two args are only used by
    // updateDoc, since they have to be expressed in the line
    // numbers before the update.
    function setSelection(doc, anchor, head, bias, checkAtomic) {
        var sel = doc.sel;
        sel.goalColumn = null;
        // Skip over atomic spans.
        if (checkAtomic || !posEq(anchor, sel.anchor))
            anchor = skipAtomic(doc, anchor, bias, checkAtomic != "push");
        if (checkAtomic || !posEq(head, sel.head))
            head = skipAtomic(doc, head, bias, checkAtomic != "push");

        if (posEq(sel.anchor, anchor) && posEq(sel.head, head)) return;

        sel.anchor = anchor; sel.head = head;
        var inv = posLess(head, anchor);
        sel.from = inv ? head : anchor;
        sel.to = inv ? anchor : head;

        if (doc.cm)
            doc.cm.curOp.updateInput = doc.cm.curOp.selectionChanged = true;

        signalLater(doc, "cursorActivity", doc);
    }

    function reCheckSelection(cm) {
        setSelection(cm.doc, cm.doc.sel.from, cm.doc.sel.to, null, "push");
    }

    function skipAtomic(doc, pos, bias, mayClear) {
        var flipped = false, curPos = pos;
        var dir = bias || 1;
        doc.cantEdit = false;
        search: for (;;) {
            var line = getLine(doc, curPos.line), toClear;
            if (line.markedSpans) {
                for (var i = 0; i < line.markedSpans.length; ++i) {
                    var sp = line.markedSpans[i], m = sp.marker;
                    if ((sp.from == null || (m.inclusiveLeft ? sp.from <= curPos.ch : sp.from < curPos.ch)) &&
                        (sp.to == null || (m.inclusiveRight ? sp.to >= curPos.ch : sp.to > curPos.ch))) {
                        if (mayClear && m.clearOnEnter) {
                            (toClear || (toClear = [])).push(m);
                            continue;
                        } else if (!m.atomic) continue;
                        var newPos = m.find()[dir < 0 ? "from" : "to"];
                        if (posEq(newPos, curPos)) {
                            newPos.ch += dir;
                            if (newPos.ch < 0) {
                                if (newPos.line > doc.first) newPos = clipPos(doc, Pos(newPos.line - 1));
                                else newPos = null;
                            } else if (newPos.ch > line.text.length) {
                                if (newPos.line < doc.first + doc.size - 1) newPos = Pos(newPos.line + 1, 0);
                                else newPos = null;
                            }
                            if (!newPos) {
                                if (flipped) {
                                    // Driven in a corner -- no valid cursor position found at all
                                    // -- try again *with* clearing, if we didn't already
                                    if (!mayClear) return skipAtomic(doc, pos, bias, true);
                                    // Otherwise, turn off editing until further notice, and return the start of the doc
                                    doc.cantEdit = true;
                                    return Pos(doc.first, 0);
                                }
                                flipped = true; newPos = pos; dir = -dir;
                            }
                        }
                        curPos = newPos;
                        continue search;
                    }
                }
                if (toClear) for (var i = 0; i < toClear.length; ++i) toClear[i].clear();
            }
            return curPos;
        }
    }

    // SCROLLING

    function scrollCursorIntoView(cm) {
        var coords = scrollPosIntoView(cm, cm.doc.sel.head);
        if (!cm.state.focused) return;
        var display = cm.display, box = getPixelRect(display.sizer), doScroll = null;
        if (coords.top + box.top < 0) doScroll = true;
        else if (coords.bottom + box.top > (window.innerHeight || document.documentElement.clientHeight)) doScroll = false;
        if (doScroll != null && !phantom) {
            var hidden = display.cursor.style.display == "none";
            if (hidden) {
                display.cursor.style.display = "";
                display.cursor.style.left = coords.left + "px";
                display.cursor.style.top = (coords.top - display.viewOffset) + "px";
            }
            display.cursor.scrollIntoView(doScroll);
            if (hidden) display.cursor.style.display = "none";
        }
    }

    function scrollPosIntoView(cm, pos) {
        for (;;) {
            var changed = false, coords = cursorCoords(cm, pos);
            var scrollPos = calculateScrollPos(cm, coords.left, coords.top, coords.left, coords.bottom);
            var startTop = cm.doc.scrollTop, startLeft = cm.doc.scrollLeft;
            if (scrollPos.scrollTop != null) {
                setScrollTop(cm, scrollPos.scrollTop);
                if (Math.abs(cm.doc.scrollTop - startTop) > 1) changed = true;
            }
            if (scrollPos.scrollLeft != null) {
                setScrollLeft(cm, scrollPos.scrollLeft);
                if (Math.abs(cm.doc.scrollLeft - startLeft) > 1) changed = true;
            }
            if (!changed) return coords;
        }
    }

    function scrollIntoView(cm, x1, y1, x2, y2) {
        var scrollPos = calculateScrollPos(cm, x1, y1, x2, y2);
        if (scrollPos.scrollTop != null) setScrollTop(cm, scrollPos.scrollTop);
        if (scrollPos.scrollLeft != null) setScrollLeft(cm, scrollPos.scrollLeft);
    }

    function calculateScrollPos(cm, x1, y1, x2, y2) {
        var display = cm.display, pt = paddingTop(display);
        y1 += pt; y2 += pt;
        var screen = display.scroller.clientHeight - scrollerCutOff, screentop = display.scroller.scrollTop, result = {};
        var docBottom = cm.doc.height + 2 * pt;
        var atTop = y1 < pt + 10, atBottom = y2 + pt > docBottom - 10;
        if (y1 < screentop) result.scrollTop = atTop ? 0 : Math.max(0, y1);
        else if (y2 > screentop + screen) result.scrollTop = (atBottom ? docBottom : y2) - screen;

        var screenw = display.scroller.clientWidth - scrollerCutOff, screenleft = display.scroller.scrollLeft;
        x1 += display.gutters.offsetWidth; x2 += display.gutters.offsetWidth;
        var gutterw = display.gutters.offsetWidth;
        var atLeft = x1 < gutterw + 10;
        if (x1 < screenleft + gutterw || atLeft) {
            if (atLeft) x1 = 0;
            result.scrollLeft = Math.max(0, x1 - 10 - gutterw);
        } else if (x2 > screenw + screenleft - 3) {
            result.scrollLeft = x2 + 10 - screenw;
        }
        return result;
    }

    // API UTILITIES

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

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

        var indentString = "", pos = 0;
        if (cm.options.indentWithTabs)
            for (var i = Math.floor(indentation / tabSize); i; --i) {pos += tabSize; indentString += "\t";}
        if (pos < indentation) indentString += spaceStr(indentation - pos);

        if (indentString != curSpaceString)
            replaceRange(cm.doc, indentString, Pos(n, 0), Pos(n, curSpaceString.length), "+input");
        line.stateAfter = null;
    }

    function changeLine(cm, handle, op) {
        var no = handle, line = handle, doc = cm.doc;
        if (typeof handle == "number") line = getLine(doc, clipLine(doc, handle));
        else no = lineNo(handle);
        if (no == null) return null;
        if (op(line, no)) regChange(cm, no, no + 1);
        else return null;
        return line;
    }

    function findPosH(doc, dir, unit, visually) {
        var end = doc.sel.head, line = end.line, ch = end.ch;
        var lineObj = getLine(doc, line);
        function findNextLine() {
            var l = line + dir;
            if (l < doc.first || l >= doc.first + doc.size) return false;
            line = l;
            return lineObj = getLine(doc, l);
        }
        function moveOnce(boundToLine) {
            var next = (visually ? moveVisually : moveLogically)(lineObj, ch, dir, true);
            if (next == null) {
                if (!boundToLine && findNextLine()) {
                    if (visually) ch = (dir < 0 ? lineRight : lineLeft)(lineObj);
                    else ch = dir < 0 ? lineObj.text.length : 0;
                } else return false;
            } else ch = next;
            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 skipAtomic(doc, Pos(line, ch), dir, true);
    }

    function findWordAt(line, pos) {
        var start = pos.ch, end = pos.ch;
        if (line) {
            if (pos.after === false || end == line.length) --start; else ++end;
            var startChar = line.charAt(start);
            var check = isWordChar(startChar) ? isWordChar :
                /\s/.test(startChar) ? function(ch) {return /\s/.test(ch);} :
                    function(ch) {return !/\s/.test(ch) && !isWordChar(ch);};
            while (start > 0 && check(line.charAt(start - 1))) --start;
            while (end < line.length && check(line.charAt(end))) ++end;
        }
        return {from: Pos(pos.line, start), to: Pos(pos.line, end)};
    }

    function selectLine(cm, line) {
        extendSelection(cm.doc, Pos(line, 0), clipPos(cm.doc, Pos(line + 1, 0)));
    }

    // PROTOTYPE

    // The publicly visible API. Note that operation(null, f) means
    // 'wrap f in an operation, performed on its `this` parameter'

    CodeMirror.prototype = {
        focus: function(){window.focus(); focusInput(this); onFocus(this); fastPoll(this);},

        setOption: function(option, value) {
            var options = this.options, old = options[option];
            if (options[option] == value && option != "mode") return;
            options[option] = value;
            if (optionHandlers.hasOwnProperty(option))
                operation(this, optionHandlers[option])(this, value, old);
        },

        getOption: function(option) {return this.options[option];},
        getDoc: function() {return this.doc;},

        addKeyMap: function(map) {
            this.state.keyMaps.push(map);
        },
        removeKeyMap: function(map) {
            var maps = this.state.keyMaps;
            for (var i = 0; i < maps.length; ++i)
                if ((typeof map == "string" ? maps[i].name : maps[i]) == map) {
                    maps.splice(i, 1);
                    return true;
                }
        },

        addOverlay: operation(null, function(spec, options) {
            var mode = spec.token ? spec : CodeMirror.getMode(this.options, spec);
            if (mode.startState) throw new Error("Overlays may not be stateful.");
            this.state.overlays.push({mode: mode, modeSpec: spec, opaque: options && options.opaque});
            this.state.modeGen++;
            regChange(this);
        }),
        removeOverlay: operation(null, function(spec) {
            var overlays = this.state.overlays;
            for (var i = 0; i < overlays.length; ++i) {
                if (overlays[i].modeSpec == spec) {
                    overlays.splice(i, 1);
                    this.state.modeGen++;
                    regChange(this);
                    return;
                }
            }
        }),

        indentLine: operation(null, function(n, dir, aggressive) {
            if (typeof dir != "string") {
                if (dir == null) dir = this.options.smartIndent ? "smart" : "prev";
                else dir = dir ? "add" : "subtract";
            }
            if (isLine(this.doc, n)) indentLine(this, n, dir, aggressive);
        }),
        indentSelection: operation(null, function(how) {
            var sel = this.doc.sel;
            if (posEq(sel.from, sel.to)) return indentLine(this, sel.from.line, how);
            var e = sel.to.line - (sel.to.ch ? 0 : 1);
            for (var i = sel.from.line; i <= e; ++i) indentLine(this, i, how);
        }),

        // Fetch the parser token for a given character. Useful for hacks
        // that want to inspect the mode state (say, for completion).
        getTokenAt: function(pos) {
            var doc = this.doc;
            pos = clipPos(doc, pos);
            var state = getStateBefore(this, pos.line), mode = this.doc.mode;
            var line = getLine(doc, pos.line);
            var stream = new StringStream(line.text, this.options.tabSize);
            while (stream.pos < 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, // Deprecated, use 'type' instead
                type: style || null,
                state: state};
        },

        getStateAfter: function(line) {
            var doc = this.doc;
            line = clipLine(doc, line == null ? doc.first + doc.size - 1: line);
            return getStateBefore(this, line + 1);
        },

        cursorCoords: function(start, mode) {
            var pos, sel = this.doc.sel;
            if (start == null) pos = sel.head;
            else if (typeof start == "object") pos = clipPos(this.doc, start);
            else pos = start ? sel.from : sel.to;
            return cursorCoords(this, pos, mode || "page");
        },

        charCoords: function(pos, mode) {
            return charCoords(this, clipPos(this.doc, pos), mode || "page");
        },

        coordsChar: function(coords) {
            var off = getPixelRect(this.display.lineSpace);
            var scrollY = window.pageYOffset || (document.documentElement || document.body).scrollTop;
            var scrollX = window.pageXOffset || (document.documentElement || document.body).scrollLeft;
            return coordsChar(this, coords.left - off.left - scrollX, coords.top - off.top - scrollY);
        },

        defaultTextHeight: function() { return textHeight(this.display); },

        setGutterMarker: operation(null, function(line, gutterID, value) {
            return changeLine(this, line, function(line) {
                var markers = line.gutterMarkers || (line.gutterMarkers = {});
                markers[gutterID] = value;
                if (!value && isEmpty(markers)) line.gutterMarkers = null;
                return true;
            });
        }),

        clearGutter: operation(null, function(gutterID) {
            var cm = this, doc = cm.doc, i = doc.first;
            doc.iter(function(line) {
                if (line.gutterMarkers && line.gutterMarkers[gutterID]) {
                    line.gutterMarkers[gutterID] = null;
                    regChange(cm, i, i + 1);
                    if (isEmpty(line.gutterMarkers)) line.gutterMarkers = null;
                }
                ++i;
            });
        }),

        addLineClass: operation(null, function(handle, where, cls) {
            return changeLine(this, handle, function(line) {
                var prop = where == "text" ? "textClass" : where == "background" ? "bgClass" : "wrapClass";
                if (!line[prop]) line[prop] = cls;
                else if (new RegExp("\\b" + cls + "\\b").test(line[prop])) return false;
                else line[prop] += " " + cls;
                return true;
            });
        }),

        removeLineClass: operation(null, function(handle, where, cls) {
            return changeLine(this, handle, function(line) {
                var prop = where == "text" ? "textClass" : where == "background" ? "bgClass" : "wrapClass";
                var cur = line[prop];
                if (!cur) return false;
                else if (cls == null) line[prop] = null;
                else {
                    var upd = cur.replace(new RegExp("^" + cls + "\\b\\s*|\\s*\\b" + cls + "\\b"), "");
                    if (upd == cur) return false;
                    line[prop] = upd || null;
                }
                return true;
            });
        }),

        addLineWidget: operation(null, function(handle, node, options) {
            return addLineWidget(this, handle, node, options);
        }),

        removeLineWidget: function(widget) { widget.clear(); },

        lineInfo: function(line) {
            if (typeof line == "number") {
                if (!isLine(this.doc, line)) return null;
                var n = line;
                line = getLine(this.doc, line);
                if (!line) return null;
            } else {
                var n = lineNo(line);
                if (n == null) return null;
            }
            return {line: n, handle: line, text: line.text, gutterMarkers: line.gutterMarkers,
                textClass: line.textClass, bgClass: line.bgClass, wrapClass: line.wrapClass,
                widgets: line.widgets};
        },

        getViewport: function() { return {from: this.display.showingFrom, to: this.display.showingTo};},

        addWidget: function(pos, node, scroll, vert, horiz) {
            var display = this.display;
            pos = cursorCoords(this, clipPos(this.doc, pos));
            var top = pos.bottom, left = pos.left;
            node.style.position = "absolute";
            display.sizer.appendChild(node);
            if (vert == "over") {
                top = pos.top;
            } else if (vert == "above" || vert == "near") {
                var vspace = Math.max(display.wrapper.clientHeight, this.doc.height),
                    hspace = Math.max(display.sizer.clientWidth, display.lineSpace.clientWidth);
                // Default to positioning above (if specified and possible); otherwise default to positioning below
                if ((vert == 'above' || pos.bottom + node.offsetHeight > vspace) && pos.top > node.offsetHeight)
                    top = pos.top - node.offsetHeight;
                else if (pos.bottom + node.offsetHeight <= vspace)
                    top = pos.bottom;
                if (left + node.offsetWidth > hspace)
                    left = hspace - node.offsetWidth;
            }
            node.style.top = (top + paddingTop(display)) + "px";
            node.style.left = node.style.right = "";
            if (horiz == "right") {
                left = display.sizer.clientWidth - node.offsetWidth;
                node.style.right = "0px";
            } else {
                if (horiz == "left") left = 0;
                else if (horiz == "middle") left = (display.sizer.clientWidth - node.offsetWidth) / 2;
                node.style.left = left + "px";
            }
            if (scroll)
                scrollIntoView(this, left, top, left + node.offsetWidth, top + node.offsetHeight);
        },

        triggerOnKeyDown: operation(null, onKeyDown),

        execCommand: function(cmd) {return commands[cmd](this);},

        // Stuff used by commands, probably not much use to outside code.
        moveH: operation(null, function(dir, unit) {
            var sel = this.doc.sel, pos = dir < 0 ? sel.from : sel.to;
            if (sel.shift || sel.extend || posEq(sel.from, sel.to))
                pos = findPosH(this.doc, dir, unit, this.options.rtlMoveVisually);
            extendSelection(this.doc, pos, pos, dir);
        }),

        deleteH: operation(null, function(dir, unit) {
            var sel = this.doc.sel;
            if (!posEq(sel.from, sel.to)) replaceRange(this.doc, "", sel.from, sel.to, "+delete");
            else replaceRange(this.doc, "", sel.from, findPosH(this.doc, dir, unit, false), "+delete");
            this.curOp.userSelChange = true;
        }),

        moveV: operation(null, function(dir, unit) {
            var doc = this.doc, display = this.display;
            var cur = doc.sel.head, pos = cursorCoords(this, cur, "div");
            var x = pos.left, y;
            if (doc.sel.goalColumn != null) x = doc.sel.goalColumn;
            if (unit == "page") {
                var pageSize = Math.min(display.wrapper.clientHeight, window.innerHeight || document.documentElement.clientHeight);
                y = pos.top + dir * pageSize;
            } else if (unit == "line") {
                y = dir > 0 ? pos.bottom + 3 : pos.top - 3;
            }
            do {
                var target = coordsChar(this, x, y);
                y += dir * 5;
            } while (target.outside && (dir < 0 ? y > 0 : y < doc.height));

            if (unit == "page") display.scrollbarV.scrollTop += charCoords(this, target, "div").top - pos.top;
            extendSelection(this.doc, target, target, dir);
            doc.sel.goalColumn = x;
        }),

        toggleOverwrite: function() {
            if (this.state.overwrite = !this.state.overwrite)
                this.display.cursor.className += " CodeMirror-overwrite";
            else
                this.display.cursor.className = this.display.cursor.className.replace(" CodeMirror-overwrite", "");
        },

        scrollTo: operation(null, function(x, y) {
            this.curOp.updateScrollPos = {scrollLeft: x, scrollTop: y};
        }),
        getScrollInfo: function() {
            var scroller = this.display.scroller, co = scrollerCutOff;
            return {left: scroller.scrollLeft, top: scroller.scrollTop,
                height: scroller.scrollHeight - co, width: scroller.scrollWidth - co,
                clientHeight: scroller.clientHeight - co, clientWidth: scroller.clientWidth - co};
        },

        scrollIntoView: function(pos) {
            if (typeof pos == "number") pos = Pos(pos, 0);
            if (!pos || pos.line != null) {
                pos = pos ? clipPos(this.doc, pos) : this.doc.sel.head;
                scrollPosIntoView(this, pos);
            } else {
                scrollIntoView(this, pos.left, pos.top, pos.right, pos.bottom);
            }
        },

        setSize: function(width, height) {
            function interpret(val) {
                return typeof val == "number" || /^\d+$/.test(String(val)) ? val + "px" : val;
            }
            if (width != null) this.display.wrapper.style.width = interpret(width);
            if (height != null) this.display.wrapper.style.height = interpret(height);
            this.refresh();
        },

        on: function(type, f) {on(this, type, f);},
        off: function(type, f) {off(this, type, f);},

        operation: function(f){return runInOp(this, f);},

        refresh: operation(null, function() {
            clearCaches(this);
            this.curOp.updateScrollPos = {scrollTop: this.doc.scrollTop, scrollLeft: this.doc.scrollLeft};
            regChange(this);
        }),

        swapDoc: operation(null, function(doc) {
            var old = this.doc;
            old.cm = null;
            attachDoc(this, doc);
            clearCaches(this);
            this.curOp.updateScrollPos = {scrollTop: doc.scrollTop, scrollLeft: doc.scrollLeft};
            return old;
        }),

        getInputField: function(){return this.display.input;},
        getWrapperElement: function(){return this.display.wrapper;},
        getScrollerElement: function(){return this.display.scroller;},
        getGutterElement: function(){return this.display.gutters;}
    };

    // OPTION DEFAULTS

    var optionHandlers = CodeMirror.optionHandlers = {};

    // The default configuration options.
    var defaults = CodeMirror.defaults = {};

    function option(name, deflt, handle, notOnInit) {
        CodeMirror.defaults[name] = deflt;
        if (handle) optionHandlers[name] =
            notOnInit ? function(cm, val, old) {if (old != Init) handle(cm, val, old);} : handle;
    }

    var Init = CodeMirror.Init = {toString: function(){return "CodeMirror.Init";}};

    // These two are, on init, called from the constructor because they
    // have to be initialized before the editor can start at all.
    option("value", "", function(cm, val) {
        cm.setValue(val);
    }, true);
    option("mode", null, function(cm, val) {
        cm.doc.modeOption = val;
        loadMode(cm);
    }, true);

    option("indentUnit", 2, loadMode, true);
    option("indentWithTabs", false);
    option("smartIndent", true);
    option("tabSize", 4, function(cm) {
        loadMode(cm);
        clearCaches(cm);
        regChange(cm);
    }, true);
    option("electricChars", true);
    option("rtlMoveVisually", !windows);

    option("theme", "default", function(cm) {
        themeChanged(cm);
        guttersChanged(cm);
    }, true);
    option("keyMap", "default", keyMapChanged);
    option("extraKeys", null);

    option("onKeyEvent", null);
    option("onDragEvent", null);

    option("lineWrapping", false, wrappingChanged, true);
    option("gutters", [], function(cm) {
        setGuttersForLineNumbers(cm.options);
        guttersChanged(cm);
    }, true);
    option("fixedGutter", true, function(cm, val) {
        cm.display.gutters.style.left = val ? compensateForHScroll(cm.display) + "px" : "0";
        cm.refresh();
    }, true);
    option("lineNumbers", false, function(cm) {
        setGuttersForLineNumbers(cm.options);
        guttersChanged(cm);
    }, true);
    option("firstLineNumber", 1, guttersChanged, true);
    option("lineNumberFormatter", function(integer) {return integer;}, guttersChanged, true);
    option("showCursorWhenSelecting", false, updateSelection, true);

    option("readOnly", false, function(cm, val) {
        if (val == "nocursor") {onBlur(cm); cm.display.input.blur();}
        else if (!val) resetInput(cm, true);
    });
    option("dragDrop", true);

    option("cursorBlinkRate", 530);
    option("cursorHeight", 1);
    option("workTime", 100);
    option("workDelay", 100);
    option("flattenSpans", true);
    option("pollInterval", 100);
    option("undoDepth", 40, function(cm, val){cm.doc.history.undoDepth = val;});
    option("viewportMargin", 10, function(cm){cm.refresh();}, true);

    option("tabindex", null, function(cm, val) {
        cm.display.input.tabIndex = val || "";
    });
    option("autofocus", null);

    // MODE DEFINITION AND QUERYING

    // Known modes, by name and by MIME
    var modes = CodeMirror.modes = {}, mimeModes = CodeMirror.mimeModes = {};

    CodeMirror.defineMode = function(name, mode) {
        if (!CodeMirror.defaults.mode && name != "null") CodeMirror.defaults.mode = name;
        if (arguments.length > 2) {
            mode.dependencies = [];
            for (var i = 2; i < arguments.length; ++i) mode.dependencies.push(arguments[i]);
        }
        modes[name] = mode;
    };

    CodeMirror.defineMIME = function(mime, spec) {
        mimeModes[mime] = spec;
    };

    CodeMirror.resolveMode = function(spec) {
        if (typeof spec == "string" && mimeModes.hasOwnProperty(spec))
            spec = mimeModes[spec];
        else if (typeof spec == "string" && /^[\w\-]+\/[\w\-]+\+xml$/.test(spec))
            return CodeMirror.resolveMode("application/xml");
        if (typeof spec == "string") return {name: spec};
        else return spec || {name: "null"};
    };

    CodeMirror.getMode = function(options, spec) {
        spec = CodeMirror.resolveMode(spec);
        var mfactory = modes[spec.name];
        if (!mfactory) return CodeMirror.getMode(options, "text/plain");
        var modeObj = mfactory(options, spec);
        if (modeExtensions.hasOwnProperty(spec.name)) {
            var exts = modeExtensions[spec.name];
            for (var prop in exts) {
                if (!exts.hasOwnProperty(prop)) continue;
                if (modeObj.hasOwnProperty(prop)) modeObj["_" + prop] = modeObj[prop];
                modeObj[prop] = exts[prop];
            }
        }
        modeObj.name = spec.name;
        return modeObj;
    };

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

    var modeExtensions = CodeMirror.modeExtensions = {};
    CodeMirror.extendMode = function(mode, properties) {
        var exts = modeExtensions.hasOwnProperty(mode) ? modeExtensions[mode] : (modeExtensions[mode] = {});
        copyObj(properties, exts);
    };

    // EXTENSIONS

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

    CodeMirror.defineOption = option;

    var initHooks = [];
    CodeMirror.defineInitHook = function(f) {initHooks.push(f);};

    // MODE STATE HANDLING

    // 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;

    CodeMirror.innerMode = function(mode, state) {
        while (mode.innerMode) {
            var info = mode.innerMode(state);
            state = info.state;
            mode = info.mode;
        }
        return info || {mode: mode, state: state};
    };

    // STANDARD COMMANDS

    var commands = CodeMirror.commands = {
        selectAll: function(cm) {cm.setSelection(Pos(cm.firstLine(), 0), Pos(cm.lastLine()));},
        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, Pos(from.line + 1, 0), "+delete");
            else cm.replaceRange("", from, sel ? to : Pos(from.line), "+delete");
        },
        deleteLine: function(cm) {
            var l = cm.getCursor().line;
            cm.replaceRange("", Pos(l, 0), Pos(l), "+delete");
        },
        undo: function(cm) {cm.undo();},
        redo: function(cm) {cm.redo();},
        goDocStart: function(cm) {cm.extendSelection(Pos(cm.firstLine(), 0));},
        goDocEnd: function(cm) {cm.extendSelection(Pos(cm.lastLine()));},
        goLineStart: function(cm) {
            cm.extendSelection(lineStart(cm, cm.getCursor().line));
        },
        goLineStartSmart: function(cm) {
            var cur = cm.getCursor(), start = lineStart(cm, cur.line);
            var line = cm.getLineHandle(start.line);
            var order = getOrder(line);
            if (!order || order[0].level == 0) {
                var firstNonWS = Math.max(0, line.text.search(/\S/));
                var inWS = cur.line == start.line && cur.ch <= firstNonWS && cur.ch;
                cm.extendSelection(Pos(start.line, inWS ? 0 : firstNonWS));
            } else cm.extendSelection(start);
        },
        goLineEnd: function(cm) {
            cm.extendSelection(lineEnd(cm, cm.getCursor().line));
        },
        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");},
        delCharBefore: function(cm) {cm.deleteH(-1, "char");},
        delCharAfter: function(cm) {cm.deleteH(1, "char");},
        delWordBefore: function(cm) {cm.deleteH(-1, "word");},
        delWordAfter: 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", "+input");},
        defaultTab: function(cm) {
            if (cm.somethingSelected()) cm.indentSelection("add");
            else cm.replaceSelection("\t", "end", "+input");
        },
        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),
                    Pos(cur.line, cur.ch - 1), Pos(cur.line, cur.ch + 1));
        },
        newlineAndIndent: function(cm) {
            operation(cm, function() {
                cm.replaceSelection("\n", "end", "+input");
                cm.indentLine(cm.getCursor().line, null, true);
            })();
        },
        toggleOverwrite: function(cm) {cm.toggleOverwrite();}
    };

    // STANDARD KEYMAPS

    var keyMap = CodeMirror.keyMap = {};
    keyMap.basic = {
        "Left": "goCharLeft", "Right": "goCharRight", "Up": "goLineUp", "Down": "goLineDown",
        "End": "goLineEnd", "Home": "goLineStartSmart", "PageUp": "goPageUp", "PageDown": "goPageDown",
        "Delete": "delCharAfter", "Backspace": "delCharBefore", "Tab": "defaultTab", "Shift-Tab": "indentAuto",
        "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": "delWordBefore", "Ctrl-Delete": "delWordAfter", "Ctrl-S": "save", "Ctrl-F": "find",
        "Ctrl-G": "findNext", "Shift-Ctrl-G": "findPrev", "Shift-Ctrl-F": "replace", "Shift-Ctrl-R": "replaceAll",
        "Ctrl-[": "indentLess", "Ctrl-]": "indentMore",
        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": "delWordBefore",
        "Ctrl-Alt-Backspace": "delWordAfter", "Alt-Delete": "delWordAfter", "Cmd-S": "save", "Cmd-F": "find",
        "Cmd-G": "findNext", "Shift-Cmd-G": "findPrev", "Cmd-Alt-F": "replace", "Shift-Cmd-Alt-F": "replaceAll",
        "Cmd-[": "indentLess", "Cmd-]": "indentMore",
        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": "goPageDown", "Shift-Ctrl-V": "goPageUp", "Ctrl-D": "delCharAfter", "Ctrl-H": "delCharBefore",
        "Alt-D": "delWordAfter", "Alt-Backspace": "delWordBefore", "Ctrl-K": "killLine", "Ctrl-T": "transposeChars"
    };

    // KEYMAP DISPATCH

    function getKeyMap(val) {
        if (typeof val == "string") return keyMap[val];
        else return val;
    }

    function lookupKey(name, maps, handle) {
        function lookup(map) {
            map = getKeyMap(map);
            var found = map[name];
            if (found === false) return "stop";
            if (found != null && handle(found)) return true;
            if (map.nofallthrough) return "stop";

            var fallthrough = map.fallthrough;
            if (fallthrough == null) return false;
            if (Object.prototype.toString.call(fallthrough) != "[object Array]")
                return lookup(fallthrough);
            for (var i = 0, e = fallthrough.length; i < e; ++i) {
                var done = lookup(fallthrough[i]);
                if (done) return done;
            }
            return false;
        }

        for (var i = 0; i < maps.length; ++i) {
            var done = lookup(maps[i]);
            if (done) return done;
        }
    }
    function isModifierKey(event) {
        var name = keyNames[e_prop(event, "keyCode")];
        return name == "Ctrl" || name == "Alt" || name == "Shift" || name == "Mod";
    }
    function keyName(event, noShift) {
        var name = keyNames[e_prop(event, "keyCode")];
        if (name == null || event.altGraphKey) return false;
        if (e_prop(event, "altKey")) name = "Alt-" + name;
        if (e_prop(event, flipCtrlCmd ? "metaKey" : "ctrlKey")) name = "Ctrl-" + name;
        if (e_prop(event, flipCtrlCmd ? "ctrlKey" : "metaKey")) name = "Cmd-" + name;
        if (!noShift && e_prop(event, "shiftKey")) name = "Shift-" + name;
        return name;
    }
    CodeMirror.lookupKey = lookupKey;
    CodeMirror.isModifierKey = isModifierKey;
    CodeMirror.keyName = keyName;

    // FROMTEXTAREA

    CodeMirror.fromTextArea = function(textarea, options) {
        if (!options) options = {};
        options.value = textarea.value;
        if (!options.tabindex && textarea.tabindex)
            options.tabindex = textarea.tabindex;
        // Set autofocus to true if this textarea is focused, or if it has
        // autofocus and no other element is focused.
        if (options.autofocus == null) {
            var hasFocus = document.body;
            // doc.activeElement occasionally throws on IE
            try { hasFocus = document.activeElement; } catch(e) {}
            options.autofocus = hasFocus == textarea ||
                textarea.getAttribute("autofocus") != null && hasFocus == document.body;
        }

        function save() {textarea.value = cm.getValue();}
        if (textarea.form) {
            // Deplorable hack to make the submit method do the right thing.
            on(textarea.form, "submit", save);
            var form = textarea.form, realSubmit = form.submit;
            try {
                var wrappedSubmit = form.submit = function() {
                    save();
                    form.submit = realSubmit;
                    form.submit();
                    form.submit = wrappedSubmit;
                };
            } catch(e) {}
        }

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

    // STRING STREAM

    // Fed to the mode parsers, provides helper functions to make
    // parsers more succinct.

    // 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) || undefined;},
        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") {
                var cased = function(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 && match.index > 0) return null;
                if (match && consume !== false) this.pos += match[0].length;
                return match;
            }
        },
        current: function(){return this.string.slice(this.start, this.pos);}
    };
    CodeMirror.StringStream = StringStream;

    // TEXTMARKERS

    function TextMarker(doc, type) {
        this.lines = [];
        this.type = type;
        this.doc = doc;
    }
    CodeMirror.TextMarker = TextMarker;

    TextMarker.prototype.clear = function() {
        if (this.explicitlyCleared) return;
        var cm = this.doc.cm, withOp = cm && !cm.curOp;
        if (withOp) startOperation(cm);
        var min = null, max = null;
        for (var i = 0; i < this.lines.length; ++i) {
            var line = this.lines[i];
            var span = getMarkedSpanFor(line.markedSpans, this);
            if (span.to != null) max = lineNo(line);
            line.markedSpans = removeMarkedSpan(line.markedSpans, span);
            if (span.from != null)
                min = lineNo(line);
            else if (this.collapsed && !lineIsHidden(this.doc, line) && cm)
                updateLineHeight(line, textHeight(cm.display));
        }
        if (cm && this.collapsed && !cm.options.lineWrapping) for (var i = 0; i < this.lines.length; ++i) {
            var visual = visualLine(cm.doc, this.lines[i]), len = lineLength(cm.doc, visual);
            if (len > cm.display.maxLineLength) {
                cm.display.maxLine = visual;
                cm.display.maxLineLength = len;
                cm.display.maxLineChanged = true;
            }
        }

        if (min != null && cm) regChange(cm, min, max + 1);
        this.lines.length = 0;
        this.explicitlyCleared = true;
        if (this.collapsed && this.doc.cantEdit) {
            this.doc.cantEdit = false;
            if (cm) reCheckSelection(cm);
        }
        if (withOp) endOperation(cm);
        signalLater(this, "clear");
    };

    TextMarker.prototype.find = function() {
        var from, to;
        for (var i = 0; i < this.lines.length; ++i) {
            var line = this.lines[i];
            var span = getMarkedSpanFor(line.markedSpans, this);
            if (span.from != null || span.to != null) {
                var found = lineNo(line);
                if (span.from != null) from = Pos(found, span.from);
                if (span.to != null) to = Pos(found, span.to);
            }
        }
        if (this.type == "bookmark") return from;
        return from && {from: from, to: to};
    };

    TextMarker.prototype.getOptions = function(copyWidget) {
        var repl = this.replacedWith;
        return {className: this.className,
            inclusiveLeft: this.inclusiveLeft, inclusiveRight: this.inclusiveRight,
            atomic: this.atomic,
            collapsed: this.collapsed,
            clearOnEnter: this.clearOnEnter,
            replacedWith: copyWidget ? repl && repl.cloneNode(true) : repl,
            readOnly: this.readOnly,
            startStyle: this.startStyle, endStyle: this.endStyle};
    };

    TextMarker.prototype.attachLine = function(line) {
        if (!this.lines.length && this.doc.cm) {
            var op = this.doc.cm.curOp;
            if (!op.maybeHiddenMarkers || indexOf(op.maybeHiddenMarkers, this) == -1)
                (op.maybeUnhiddenMarkers || (op.maybeUnhiddenMarkers = [])).push(this);
        }
        this.lines.push(line);
    };
    TextMarker.prototype.detachLine = function(line) {
        this.lines.splice(indexOf(this.lines, line), 1);
        if (!this.lines.length && this.doc.cm) {
            var op = this.doc.cm.curOp;
            (op.maybeHiddenMarkers || (op.maybeHiddenMarkers = [])).push(this);
        }
    };

    function markText(doc, from, to, options, type) {
        if (options && options.shared) return markTextShared(doc, from, to, options, type);
        if (doc.cm && !doc.cm.curOp) return operation(doc.cm, markText)(doc, from, to, options, type);

        var marker = new TextMarker(doc, type);
        if (type == "range" && !posLess(from, to)) return marker;
        if (options) copyObj(options, marker);
        if (marker.replacedWith) {
            marker.collapsed = true;
            marker.replacedWith = elt("span", [marker.replacedWith], "CodeMirror-widget");
        }
        if (marker.collapsed) sawCollapsedSpans = true;

        var curLine = from.line, size = 0, collapsedAtStart, collapsedAtEnd, cm = doc.cm, updateMaxLine;
        doc.iter(curLine, to.line + 1, function(line) {
            if (cm && marker.collapsed && !cm.options.lineWrapping && visualLine(doc, line) == cm.display.maxLine)
                updateMaxLine = true;
            var span = {from: null, to: null, marker: marker};
            size += line.text.length;
            if (curLine == from.line) {span.from = from.ch; size -= from.ch;}
            if (curLine == to.line) {span.to = to.ch; size -= line.text.length - to.ch;}
            if (marker.collapsed) {
                if (curLine == to.line) collapsedAtEnd = collapsedSpanAt(line, to.ch);
                if (curLine == from.line) collapsedAtStart = collapsedSpanAt(line, from.ch);
                else updateLineHeight(line, 0);
            }
            addMarkedSpan(line, span);
            ++curLine;
        });
        if (marker.collapsed) doc.iter(from.line, to.line + 1, function(line) {
            if (lineIsHidden(doc, line)) updateLineHeight(line, 0);
        });

        if (marker.readOnly) {
            sawReadOnlySpans = true;
            if (doc.history.done.length || doc.history.undone.length)
                doc.clearHistory();
        }
        if (marker.collapsed) {
            if (collapsedAtStart != collapsedAtEnd)
                throw new Error("Inserting collapsed marker overlapping an existing one");
            marker.size = size;
            marker.atomic = true;
        }
        if (cm) {
            if (updateMaxLine) cm.curOp.updateMaxLine = true;
            if (marker.className || marker.startStyle || marker.endStyle || marker.collapsed)
                regChange(cm, from.line, to.line + 1);
            if (marker.atomic) reCheckSelection(cm);
        }
        return marker;
    }

    // SHARED TEXTMARKERS

    function SharedTextMarker(markers, primary) {
        this.markers = markers;
        this.primary = primary;
        for (var i = 0, me = this; i < markers.length; ++i) {
            markers[i].parent = this;
            on(markers[i], "clear", function(){me.clear();});
        }
    }
    CodeMirror.SharedTextMarker = SharedTextMarker;

    SharedTextMarker.prototype.clear = function() {
        if (this.explicitlyCleared) return;
        this.explicitlyCleared = true;
        for (var i = 0; i < this.markers.length; ++i)
            this.markers[i].clear();
        signalLater(this, "clear");
    };
    SharedTextMarker.prototype.find = function() {
        return this.primary.find();
    };
    SharedTextMarker.prototype.getOptions = function(copyWidget) {
        var inner = this.primary.getOptions(copyWidget);
        inner.shared = true;
        return inner;
    };

    function markTextShared(doc, from, to, options, type) {
        options = copyObj(options);
        options.shared = false;
        var markers = [markText(doc, from, to, options, type)], primary = markers[0];
        linkedDocs(doc, function(doc) {
            markers.push(markText(doc, clipPos(doc, from), clipPos(doc, to), options, type));
            for (var i = 0; i < doc.linked.length; ++i)
                if (doc.linked[i].isParent) return;
            primary = lst(markers);
        });
        return new SharedTextMarker(markers, primary);
    }

    // TEXTMARKER SPANS

    function getMarkedSpanFor(spans, marker) {
        if (spans) for (var i = 0; i < spans.length; ++i) {
            var span = spans[i];
            if (span.marker == marker) return span;
        }
    }
    function removeMarkedSpan(spans, span) {
        for (var r, i = 0; i < spans.length; ++i)
            if (spans[i] != span) (r || (r = [])).push(spans[i]);
        return r;
    }
    function addMarkedSpan(line, span) {
        line.markedSpans = line.markedSpans ? line.markedSpans.concat([span]) : [span];
        span.marker.attachLine(line);
    }

    function markedSpansBefore(old, startCh, isInsert) {
        if (old) for (var i = 0, nw; i < old.length; ++i) {
            var span = old[i], marker = span.marker;
            var startsBefore = span.from == null || (marker.inclusiveLeft ? span.from <= startCh : span.from < startCh);
            if (startsBefore || marker.type == "bookmark" && span.from == startCh && (!isInsert || !span.marker.insertLeft)) {
                var endsAfter = span.to == null || (marker.inclusiveRight ? span.to >= startCh : span.to > startCh);
                (nw || (nw = [])).push({from: span.from,
                    to: endsAfter ? null : span.to,
                    marker: marker});
            }
        }
        return nw;
    }

    function markedSpansAfter(old, endCh, isInsert) {
        if (old) for (var i = 0, nw; i < old.length; ++i) {
            var span = old[i], marker = span.marker;
            var endsAfter = span.to == null || (marker.inclusiveRight ? span.to >= endCh : span.to > endCh);
            if (endsAfter || marker.type == "bookmark" && span.from == endCh && (!isInsert || span.marker.insertLeft)) {
                var startsBefore = span.from == null || (marker.inclusiveLeft ? span.from <= endCh : span.from < endCh);
                (nw || (nw = [])).push({from: startsBefore ? null : span.from - endCh,
                    to: span.to == null ? null : span.to - endCh,
                    marker: marker});
            }
        }
        return nw;
    }

    function stretchSpansOverChange(doc, change) {
        var oldFirst = isLine(doc, change.from.line) && getLine(doc, change.from.line).markedSpans;
        var oldLast = isLine(doc, change.to.line) && getLine(doc, change.to.line).markedSpans;
        if (!oldFirst && !oldLast) return null;

        var startCh = change.from.ch, endCh = change.to.ch, isInsert = posEq(change.from, change.to);
        // Get the spans that 'stick out' on both sides
        var first = markedSpansBefore(oldFirst, startCh, isInsert);
        var last = markedSpansAfter(oldLast, endCh, isInsert);

        // Next, merge those two ends
        var sameLine = change.text.length == 1, offset = lst(change.text).length + (sameLine ? startCh : 0);
        if (first) {
            // Fix up .to properties of first
            for (var i = 0; i < first.length; ++i) {
                var span = first[i];
                if (span.to == null) {
                    var found = getMarkedSpanFor(last, span.marker);
                    if (!found) span.to = startCh;
                    else if (sameLine) span.to = found.to == null ? null : found.to + offset;
                }
            }
        }
        if (last) {
            // Fix up .from in last (or move them into first in case of sameLine)
            for (var i = 0; i < last.length; ++i) {
                var span = last[i];
                if (span.to != null) span.to += offset;
                if (span.from == null) {
                    var found = getMarkedSpanFor(first, span.marker);
                    if (!found) {
                        span.from = offset;
                        if (sameLine) (first || (first = [])).push(span);
                    }
                } else {
                    span.from += offset;
                    if (sameLine) (first || (first = [])).push(span);
                }
            }
        }

        var newMarkers = [first];
        if (!sameLine) {
            // Fill gap with whole-line-spans
            var gap = change.text.length - 2, gapMarkers;
            if (gap > 0 && first)
                for (var i = 0; i < first.length; ++i)
                    if (first[i].to == null)
                        (gapMarkers || (gapMarkers = [])).push({from: null, to: null, marker: first[i].marker});
            for (var i = 0; i < gap; ++i)
                newMarkers.push(gapMarkers);
            newMarkers.push(last);
        }
        return newMarkers;
    }

    function mergeOldSpans(doc, change) {
        var old = getOldSpans(doc, change);
        var stretched = stretchSpansOverChange(doc, change);
        if (!old) return stretched;
        if (!stretched) return old;

        for (var i = 0; i < old.length; ++i) {
            var oldCur = old[i], stretchCur = stretched[i];
            if (oldCur && stretchCur) {
                spans: for (var j = 0; j < stretchCur.length; ++j) {
                    var span = stretchCur[j];
                    for (var k = 0; k < oldCur.length; ++k)
                        if (oldCur[k].marker == span.marker) continue spans;
                    oldCur.push(span);
                }
            } else if (stretchCur) {
                old[i] = stretchCur;
            }
        }
        return old;
    }

    function removeReadOnlyRanges(doc, from, to) {
        var markers = null;
        doc.iter(from.line, to.line + 1, function(line) {
            if (line.markedSpans) for (var i = 0; i < line.markedSpans.length; ++i) {
                var mark = line.markedSpans[i].marker;
                if (mark.readOnly && (!markers || indexOf(markers, mark) == -1))
                    (markers || (markers = [])).push(mark);
            }
        });
        if (!markers) return null;
        var parts = [{from: from, to: to}];
        for (var i = 0; i < markers.length; ++i) {
            var mk = markers[i], m = mk.find();
            for (var j = 0; j < parts.length; ++j) {
                var p = parts[j];
                if (posLess(p.to, m.from) || posLess(m.to, p.from)) continue;
                var newParts = [j, 1];
                if (posLess(p.from, m.from) || !mk.inclusiveLeft && posEq(p.from, m.from))
                    newParts.push({from: p.from, to: m.from});
                if (posLess(m.to, p.to) || !mk.inclusiveRight && posEq(p.to, m.to))
                    newParts.push({from: m.to, to: p.to});
                parts.splice.apply(parts, newParts);
                j += newParts.length - 1;
            }
        }
        return parts;
    }

    function collapsedSpanAt(line, ch) {
        var sps = sawCollapsedSpans && line.markedSpans, found;
        if (sps) for (var sp, i = 0; i < sps.length; ++i) {
            sp = sps[i];
            if (!sp.marker.collapsed) continue;
            if ((sp.from == null || sp.from < ch) &&
                (sp.to == null || sp.to > ch) &&
                (!found || found.width < sp.marker.width))
                found = sp.marker;
        }
        return found;
    }
    function collapsedSpanAtStart(line) { return collapsedSpanAt(line, -1); }
    function collapsedSpanAtEnd(line) { return collapsedSpanAt(line, line.text.length + 1); }

    function visualLine(doc, line) {
        var merged;
        while (merged = collapsedSpanAtStart(line))
            line = getLine(doc, merged.find().from.line);
        return line;
    }

    function lineIsHidden(doc, line) {
        var sps = sawCollapsedSpans && line.markedSpans;
        if (sps) for (var sp, i = 0; i < sps.length; ++i) {
            sp = sps[i];
            if (!sp.marker.collapsed) continue;
            if (sp.from == null) return true;
            if (sp.from == 0 && sp.marker.inclusiveLeft && lineIsHiddenInner(doc, line, sp))
                return true;
        }
    }
    function lineIsHiddenInner(doc, line, span) {
        if (span.to == null) {
            var end = span.marker.find().to, endLine = getLine(doc, end.line);
            return lineIsHiddenInner(doc, endLine, getMarkedSpanFor(endLine.markedSpans, span.marker));
        }
        if (span.marker.inclusiveRight && span.to == line.text.length)
            return true;
        for (var sp, i = 0; i < line.markedSpans.length; ++i) {
            sp = line.markedSpans[i];
            if (sp.marker.collapsed && sp.from == span.to &&
                (sp.marker.inclusiveLeft || span.marker.inclusiveRight) &&
                lineIsHiddenInner(doc, line, sp)) return true;
        }
    }

    function detachMarkedSpans(line) {
        var spans = line.markedSpans;
        if (!spans) return;
        for (var i = 0; i < spans.length; ++i)
            spans[i].marker.detachLine(line);
        line.markedSpans = null;
    }

    function attachMarkedSpans(line, spans) {
        if (!spans) return;
        for (var i = 0; i < spans.length; ++i)
            spans[i].marker.attachLine(line);
        line.markedSpans = spans;
    }

    // LINE WIDGETS

    var LineWidget = CodeMirror.LineWidget = function(cm, node, options) {
        for (var opt in options) if (options.hasOwnProperty(opt))
            this[opt] = options[opt];
        this.cm = cm;
        this.node = node;
    };
    function widgetOperation(f) {
        return function() {
            var withOp = !this.cm.curOp;
            if (withOp) startOperation(this.cm);
            try {var result = f.apply(this, arguments);}
            finally {if (withOp) endOperation(this.cm);}
            return result;
        };
    }
    LineWidget.prototype.clear = widgetOperation(function() {
        var ws = this.line.widgets, no = lineNo(this.line);
        if (no == null || !ws) return;
        for (var i = 0; i < ws.length; ++i) if (ws[i] == this) ws.splice(i--, 1);
        if (!ws.length) this.line.widgets = null;
        updateLineHeight(this.line, Math.max(0, this.line.height - widgetHeight(this)));
        regChange(this.cm, no, no + 1);
    });
    LineWidget.prototype.changed = widgetOperation(function() {
        var oldH = this.height;
        this.height = null;
        var diff = widgetHeight(this) - oldH;
        if (!diff) return;
        updateLineHeight(this.line, this.line.height + diff);
        var no = lineNo(this.line);
        regChange(this.cm, no, no + 1);
    });

    function widgetHeight(widget) {
        if (widget.height != null) return widget.height;
        if (!widget.node.parentNode || widget.node.parentNode.nodeType != 1)
            removeChildrenAndAdd(widget.cm.display.measure, elt("div", [widget.node], null, "position: relative"));
        return widget.height = widget.node.offsetHeight;
    }

    function addLineWidget(cm, handle, node, options) {
        var widget = new LineWidget(cm, node, options);
        if (widget.noHScroll) cm.display.alignWidgets = true;
        changeLine(cm, handle, function(line) {
            (line.widgets || (line.widgets = [])).push(widget);
            widget.line = line;
            if (!lineIsHidden(cm.doc, line) || widget.showIfHidden) {
                var aboveVisible = heightAtLine(cm, line) < cm.display.scroller.scrollTop;
                updateLineHeight(line, line.height + widgetHeight(widget));
                if (aboveVisible)
                    cm.curOp.updateScrollPos = {scrollTop: cm.doc.scrollTop + widget.height,
                        scrollLeft: cm.doc.scrollLeft};
            }
            return true;
        });
        return widget;
    }

    // LINE DATA STRUCTURE

    // Line objects. These hold state related to a line, including
    // highlighting info (the styles array).
    function makeLine(text, markedSpans, estimateHeight) {
        var line = {text: text};
        attachMarkedSpans(line, markedSpans);
        line.height = estimateHeight ? estimateHeight(line) : 1;
        return line;
    }

    function updateLine(line, text, markedSpans, estimateHeight) {
        line.text = text;
        if (line.stateAfter) line.stateAfter = null;
        if (line.styles) line.styles = null;
        if (line.order != null) line.order = null;
        detachMarkedSpans(line);
        attachMarkedSpans(line, markedSpans);
        var estHeight = estimateHeight ? estimateHeight(line) : 1;
        if (estHeight != line.height) updateLineHeight(line, estHeight);
        signalLater(line, "change");
    }

    function cleanUpLine(line) {
        line.parent = null;
        detachMarkedSpans(line);
    }

    // Run the given mode's parser over a line, update the styles
    // array, which contains alternating fragments of text and CSS
    // classes.
    function runMode(cm, text, mode, state, f) {
        var flattenSpans = cm.options.flattenSpans;
        var curText = "", curStyle = null;
        var stream = new StringStream(text, cm.options.tabSize);
        if (text == "" && mode.blankLine) mode.blankLine(state);
        while (!stream.eol()) {
            var style = mode.token(stream, state);
            if (stream.pos > 5000) {
                flattenSpans = false;
                // Webkit seems to refuse to render text nodes longer than 57444 characters
                stream.pos = Math.min(text.length, stream.start + 50000);
                style = null;
            }
            var substr = stream.current();
            stream.start = stream.pos;
            if (!flattenSpans || curStyle != style) {
                if (curText) f(curText, curStyle);
                curText = substr; curStyle = style;
            } else curText = curText + substr;
        }
        if (curText) f(curText, curStyle);
    }

    function highlightLine(cm, line, state) {
        // A styles array always starts with a number identifying the
        // mode/overlays that it is based on (for easy invalidation).
        var st = [cm.state.modeGen];
        // Compute the base array of styles
        runMode(cm, line.text, cm.doc.mode, state, function(txt, style) {st.push(txt, style);});

        // Run overlays, adjust style array.
        for (var o = 0; o < cm.state.overlays.length; ++o) {
            var overlay = cm.state.overlays[o], i = 1;
            runMode(cm, line.text, overlay.mode, true, function(txt, style) {
                var start = i, len = txt.length;
                // Ensure there's a token end at the current position, and that i points at it
                while (len) {
                    var cur = st[i], len_ = cur.length;
                    if (len_ <= len) {
                        len -= len_;
                    } else {
                        st.splice(i, 1, cur.slice(0, len), st[i+1], cur.slice(len));
                        len = 0;
                    }
                    i += 2;
                }
                if (!style) return;
                if (overlay.opaque) {
                    st.splice(start, i - start, txt, style);
                    i = start + 2;
                } else {
                    for (; start < i; start += 2) {
                        var cur = st[start+1];
                        st[start+1] = cur ? cur + " " + style : style;
                    }
                }
            });
        }

        return st;
    }

    function getLineStyles(cm, line) {
        if (!line.styles || line.styles[0] != cm.state.modeGen)
            line.styles = highlightLine(cm, line, line.stateAfter = getStateBefore(cm, lineNo(line)));
        return line.styles;
    }

    // Lightweight form of highlight -- proceed over this line and
    // update state, but don't save a style array.
    function processLine(cm, line, state) {
        var mode = cm.doc.mode;
        var stream = new StringStream(line.text, cm.options.tabSize);
        if (line.text == "" && mode.blankLine) mode.blankLine(state);
        while (!stream.eol() && stream.pos <= 5000) {
            mode.token(stream, state);
            stream.start = stream.pos;
        }
    }

    var styleToClassCache = {};
    function styleToClass(style) {
        if (!style) return null;
        return styleToClassCache[style] ||
            (styleToClassCache[style] = "cm-" + style.replace(/ +/g, " cm-"));
    }

    function lineContent(cm, realLine, measure) {
        var merged, line = realLine, lineBefore, sawBefore, simple = true;
        while (merged = collapsedSpanAtStart(line)) {
            simple = false;
            line = getLine(cm.doc, merged.find().from.line);
            if (!lineBefore) lineBefore = line;
        }

        var builder = {pre: elt("pre"), col: 0, pos: 0, display: !measure,
            measure: null, addedOne: false, cm: cm};
        if (line.textClass) builder.pre.className = line.textClass;

        do {
            builder.measure = line == realLine && measure;
            builder.pos = 0;
            builder.addToken = builder.measure ? buildTokenMeasure : buildToken;
            if (measure && sawBefore && line != realLine && !builder.addedOne) {
                measure[0] = builder.pre.appendChild(zeroWidthElement(cm.display.measure));
                builder.addedOne = true;
            }
            var next = insertLineContent(line, builder, getLineStyles(cm, line));
            sawBefore = line == lineBefore;
            if (next) {
                line = getLine(cm.doc, next.to.line);
                simple = false;
            }
        } while (next);

        if (measure && !builder.addedOne)
            measure[0] = builder.pre.appendChild(simple ? elt("span", "\u00a0") : zeroWidthElement(cm.display.measure));
        if (!builder.pre.firstChild && !lineIsHidden(cm.doc, realLine))
            builder.pre.appendChild(document.createTextNode("\u00a0"));

        return builder.pre;
    }

    var tokenSpecialChars = /[\t\u0000-\u0019\u200b\u2028\u2029\uFEFF]/g;
    function buildToken(builder, text, style, startStyle, endStyle) {
        if (!text) return;
        if (!tokenSpecialChars.test(text)) {
            builder.col += text.length;
            var content = document.createTextNode(text);
        } else {
            var content = document.createDocumentFragment(), pos = 0;
            while (true) {
                tokenSpecialChars.lastIndex = pos;
                var m = tokenSpecialChars.exec(text);
                var skipped = m ? m.index - pos : text.length - pos;
                if (skipped) {
                    content.appendChild(document.createTextNode(text.slice(pos, pos + skipped)));
                    builder.col += skipped;
                }
                if (!m) break;
                pos += skipped + 1;
                if (m[0] == "\t") {
                    var tabSize = builder.cm.options.tabSize, tabWidth = tabSize - builder.col % tabSize;
                    content.appendChild(elt("span", spaceStr(tabWidth), "cm-tab"));
                    builder.col += tabWidth;
                } else {
                    var token = elt("span", "\u2022", "cm-invalidchar");
                    token.title = "\\u" + m[0].charCodeAt(0).toString(16);
                    content.appendChild(token);
                    builder.col += 1;
                }
            }
        }
        if (style || startStyle || endStyle || builder.measure) {
            var fullStyle = style || "";
            if (startStyle) fullStyle += startStyle;
            if (endStyle) fullStyle += endStyle;
            return builder.pre.appendChild(elt("span", [content], fullStyle));
        }
        builder.pre.appendChild(content);
    }

    function buildTokenMeasure(builder, text, style, startStyle, endStyle) {
        for (var i = 0; i < text.length; ++i) {
            var ch = text.charAt(i), start = i == 0;
            if (ch >= "\ud800" && ch < "\udbff" && i < text.length - 1) {
                ch = text.slice(i, i + 2);
                ++i;
            } else if (i && builder.cm.options.lineWrapping &&
                spanAffectsWrapping.test(text.slice(i - 1, i + 1))) {
                builder.pre.appendChild(elt("wbr"));
            }
            builder.measure[builder.pos] =
                buildToken(builder, ch, style,
                    start && startStyle, i == text.length - 1 && endStyle);
            builder.pos += ch.length;
        }
        if (text.length) builder.addedOne = true;
    }

    function buildCollapsedSpan(builder, size, widget) {
        if (widget) {
            if (!builder.display) widget = widget.cloneNode(true);
            builder.pre.appendChild(widget);
            if (builder.measure && size) {
                builder.measure[builder.pos] = widget;
                builder.addedOne = true;
            }
        }
        builder.pos += size;
    }

    // Outputs a number of spans to make up a line, taking highlighting
    // and marked text into account.
    function insertLineContent(line, builder, styles) {
        var spans = line.markedSpans;
        if (!spans) {
            for (var i = 1; i < styles.length; i+=2)
                builder.addToken(builder, styles[i], styleToClass(styles[i+1]));
            return;
        }

        var allText = line.text, len = allText.length;
        var pos = 0, i = 1, text = "", style;
        var nextChange = 0, spanStyle, spanEndStyle, spanStartStyle, collapsed;
        for (;;) {
            if (nextChange == pos) { // Update current marker set
                spanStyle = spanEndStyle = spanStartStyle = "";
                collapsed = null; nextChange = Infinity;
                var foundBookmark = null;
                for (var j = 0; j < spans.length; ++j) {
                    var sp = spans[j], m = sp.marker;
                    if (sp.from <= pos && (sp.to == null || sp.to > pos)) {
                        if (sp.to != null && nextChange > sp.to) { nextChange = sp.to; spanEndStyle = ""; }
                        if (m.className) spanStyle += " " + m.className;
                        if (m.startStyle && sp.from == pos) spanStartStyle += " " + m.startStyle;
                        if (m.endStyle && sp.to == nextChange) spanEndStyle += " " + m.endStyle;
                        if (m.collapsed && (!collapsed || collapsed.marker.width < m.width))
                            collapsed = sp;
                    } else if (sp.from > pos && nextChange > sp.from) {
                        nextChange = sp.from;
                    }
                    if (m.type == "bookmark" && sp.from == pos && m.replacedWith)
                        foundBookmark = m.replacedWith;
                }
                if (collapsed && (collapsed.from || 0) == pos) {
                    buildCollapsedSpan(builder, (collapsed.to == null ? len : collapsed.to) - pos,
                        collapsed.from != null && collapsed.marker.replacedWith);
                    if (collapsed.to == null) return collapsed.marker.find();
                }
                if (foundBookmark && !collapsed) buildCollapsedSpan(builder, 0, foundBookmark);
            }
            if (pos >= len) break;

            var upto = Math.min(len, nextChange);
            while (true) {
                if (text) {
                    var end = pos + text.length;
                    if (!collapsed) {
                        var tokenText = end > upto ? text.slice(0, upto - pos) : text;
                        builder.addToken(builder, tokenText, style ? style + spanStyle : spanStyle,
                            spanStartStyle, pos + tokenText.length == nextChange ? spanEndStyle : "");
                    }
                    if (end >= upto) {text = text.slice(upto - pos); pos = upto; break;}
                    pos = end;
                    spanStartStyle = "";
                }
                text = styles[i++]; style = styleToClass(styles[i++]);
            }
        }
    }

    // DOCUMENT DATA STRUCTURE

    function updateDoc(doc, change, markedSpans, selAfter, estimateHeight) {
        function spansFor(n) {return markedSpans ? markedSpans[n] : null;}

        var from = change.from, to = change.to, text = change.text;
        var firstLine = getLine(doc, from.line), lastLine = getLine(doc, to.line);
        var lastText = lst(text), lastSpans = spansFor(text.length - 1), nlines = to.line - from.line;

        // First adjust the line structure
        if (from.ch == 0 && to.ch == 0 && lastText == "") {
            // This is a whole-line replace. Treated specially to make
            // sure line objects move the way they are supposed to.
            for (var i = 0, e = text.length - 1, added = []; i < e; ++i)
                added.push(makeLine(text[i], spansFor(i), estimateHeight));
            updateLine(lastLine, lastLine.text, lastSpans, estimateHeight);
            if (nlines) doc.remove(from.line, nlines);
            if (added.length) doc.insert(from.line, added);
        } else if (firstLine == lastLine) {
            if (text.length == 1) {
                updateLine(firstLine, firstLine.text.slice(0, from.ch) + lastText + firstLine.text.slice(to.ch),
                    lastSpans, estimateHeight);
            } else {
                for (var added = [], i = 1, e = text.length - 1; i < e; ++i)
                    added.push(makeLine(text[i], spansFor(i), estimateHeight));
                added.push(makeLine(lastText + firstLine.text.slice(to.ch), lastSpans, estimateHeight));
                updateLine(firstLine, firstLine.text.slice(0, from.ch) + text[0], spansFor(0), estimateHeight);
                doc.insert(from.line + 1, added);
            }
        } else if (text.length == 1) {
            updateLine(firstLine, firstLine.text.slice(0, from.ch) + text[0] + lastLine.text.slice(to.ch),
                spansFor(0), estimateHeight);
            doc.remove(from.line + 1, nlines);
        } else {
            updateLine(firstLine, firstLine.text.slice(0, from.ch) + text[0], spansFor(0), estimateHeight);
            updateLine(lastLine, lastText + lastLine.text.slice(to.ch), lastSpans, estimateHeight);
            for (var i = 1, e = text.length - 1, added = []; i < e; ++i)
                added.push(makeLine(text[i], spansFor(i), estimateHeight));
            if (nlines > 1) doc.remove(from.line + 1, nlines - 1);
            doc.insert(from.line + 1, added);
        }

        signalLater(doc, "change", doc, change);
        setSelection(doc, selAfter.anchor, selAfter.head, null, true);
    }

    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; },
        removeInner: function(at, n) {
            for (var i = at, e = at + n; i < e; ++i) {
                var line = this.lines[i];
                this.height -= line.height;
                cleanUpLine(line);
                signalLater(line, "delete");
            }
            this.lines.splice(at, n);
        },
        collapse: function(lines) {
            lines.splice.apply(lines, [lines.length, 0].concat(this.lines));
        },
        insertInner: function(at, lines, height) {
            this.height += height;
            this.lines = this.lines.slice(0, at).concat(lines).concat(this.lines.slice(at));
            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; },
        removeInner: function(at, n) {
            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.removeInner(at, rm);
                    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);
        },
        insertInner: 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.insertInner(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();
        },
        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;
            }
        }
    };

    var nextDocId = 0;
    var Doc = CodeMirror.Doc = function(text, mode, firstLine) {
        if (!(this instanceof Doc)) return new Doc(text, mode, firstLine);
        if (firstLine == null) firstLine = 0;

        BranchChunk.call(this, [new LeafChunk([makeLine("", null)])]);
        this.first = firstLine;
        this.scrollTop = this.scrollLeft = 0;
        this.cantEdit = false;
        this.history = makeHistory();
        this.frontier = firstLine;
        var start = Pos(firstLine, 0);
        this.sel = {from: start, to: start, head: start, anchor: start, shift: false, extend: false, goalColumn: null};
        this.id = ++nextDocId;
        this.modeOption = mode;

        if (typeof text == "string") text = splitLines(text);
        updateDoc(this, {from: start, to: start, text: text}, null, {head: start, anchor: start});
    };

    Doc.prototype = createObj(BranchChunk.prototype, {
        iter: function(from, to, op) {
            if (op) this.iterN(from - this.first, to - (from - this.first), op);
            else this.iterN(this.first, this.first + this.size, from);
        },

        insert: function(at, lines) {
            var height = 0;
            for (var i = 0, e = lines.length; i < e; ++i) height += lines[i].height;
            this.insertInner(at - this.first, lines, height);
        },
        remove: function(at, n) { this.removeInner(at - this.first, n); },

        getValue: function(lineSep) {
            var lines = getLines(this, this.first, this.first + this.size);
            if (lineSep === false) return lines;
            return lines.join(lineSep || "\n");
        },
        setValue: function(code) {
            var top = Pos(this.first, 0), last = this.first + this.size - 1;
            makeChange(this, {from: top, to: Pos(last, getLine(this, last).text.length),
                    text: splitLines(code), origin: "setValue"},
                {head: top, anchor: top}, true);
        },
        replaceRange: function(code, from, to, origin) {
            from = clipPos(this, from);
            to = to ? clipPos(this, to) : from;
            replaceRange(this, code, from, to, origin);
        },
        getRange: function(from, to, lineSep) {
            var lines = getBetween(this, clipPos(this, from), clipPos(this, to));
            if (lineSep === false) return lines;
            return lines.join(lineSep || "\n");
        },

        getLine: function(line) {var l = this.getLineHandle(line); return l && l.text;},
        setLine: function(line, text) {
            if (isLine(this, line))
                replaceRange(this, text, Pos(line, 0), clipPos(this, Pos(line)));
        },
        removeLine: function(line) {
            if (isLine(this, line))
                replaceRange(this, "", Pos(line, 0), clipPos(this, Pos(line + 1, 0)));
        },

        getLineHandle: function(line) {if (isLine(this, line)) return getLine(this, line);},
        getLineNumber: function(line) {return lineNo(line);},

        lineCount: function() {return this.size;},
        firstLine: function() {return this.first;},
        lastLine: function() {return this.first + this.size - 1;},

        clipPos: function(pos) {return clipPos(this, pos);},

        getCursor: function(start) {
            var sel = this.sel, pos;
            if (start == null || start == "head") pos = sel.head;
            else if (start == "anchor") pos = sel.anchor;
            else if (start == "end" || start === false) pos = sel.to;
            else pos = sel.from;
            return copyPos(pos);
        },
        somethingSelected: function() {return !posEq(this.sel.head, this.sel.anchor);},

        setCursor: docOperation(function(line, ch, extend) {
            var pos = clipPos(this, typeof line == "number" ? Pos(line, ch || 0) : line);
            if (extend) extendSelection(this, pos);
            else setSelection(this, pos, pos);
        }),
        setSelection: docOperation(function(anchor, head) {
            setSelection(this, clipPos(this, anchor), clipPos(this, head || anchor));
        }),
        extendSelection: docOperation(function(from, to) {
            extendSelection(this, clipPos(this, from), to && clipPos(this, to));
        }),

        getSelection: function(lineSep) {return this.getRange(this.sel.from, this.sel.to, lineSep);},
        replaceSelection: function(code, collapse, origin) {
            makeChange(this, {from: this.sel.from, to: this.sel.to, text: splitLines(code), origin: origin}, collapse || "around");
        },
        undo: docOperation(function() {makeChangeFromHistory(this, "undo");}),
        redo: docOperation(function() {makeChangeFromHistory(this, "redo");}),

        setExtending: function(val) {this.sel.extend = val;},

        historySize: function() {
            var hist = this.history;
            return {undo: hist.done.length, redo: hist.undone.length};
        },
        clearHistory: function() {this.history = makeHistory();},

        markClean: function() {
            this.history.dirtyCounter = 0;
            this.history.lastOp = this.history.lastOrigin = null;
        },
        isClean: function () {return this.history.dirtyCounter == 0;},

        getHistory: function() {
            return {done: copyHistoryArray(this.history.done),
                undone: copyHistoryArray(this.history.undone)};
        },
        setHistory: function(histData) {
            var hist = this.history = makeHistory();
            hist.done = histData.done.slice(0);
            hist.undone = histData.undone.slice(0);
        },

        markText: function(from, to, options) {
            return markText(this, clipPos(this, from), clipPos(this, to), options, "range");
        },
        setBookmark: function(pos, options) {
            var realOpts = {replacedWith: options && (options.nodeType == null ? options.widget : options),
                insertLeft: options && options.insertLeft};
            pos = clipPos(this, pos);
            return markText(this, pos, pos, realOpts, "bookmark");
        },
        findMarksAt: function(pos) {
            pos = clipPos(this, pos);
            var markers = [], spans = getLine(this, pos.line).markedSpans;
            if (spans) for (var i = 0; i < spans.length; ++i) {
                var span = spans[i];
                if ((span.from == null || span.from <= pos.ch) &&
                    (span.to == null || span.to >= pos.ch))
                    markers.push(span.marker.parent || span.marker);
            }
            return markers;
        },

        posFromIndex: function(off) {
            var ch, lineNo = this.first;
            this.iter(function(line) {
                var sz = line.text.length + 1;
                if (sz > off) { ch = off; return true; }
                off -= sz;
                ++lineNo;
            });
            return clipPos(this, Pos(lineNo, ch));
        },
        indexFromPos: function (coords) {
            coords = clipPos(this, coords);
            var index = coords.ch;
            if (coords.line < this.first || coords.ch < 0) return 0;
            this.iter(this.first, coords.line, function (line) {
                index += line.text.length + 1;
            });
            return index;
        },

        copy: function(copyHistory) {
            var doc = new Doc(getLines(this, this.first, this.first + this.size), this.modeOption, this.first);
            doc.scrollTop = this.scrollTop; doc.scrollLeft = this.scrollLeft;
            doc.sel = {from: this.sel.from, to: this.sel.to, head: this.sel.head, anchor: this.sel.anchor,
                shift: this.sel.shift, extend: false, goalColumn: this.sel.goalColumn};
            if (copyHistory) {
                doc.history.undoDepth = this.history.undoDepth;
                doc.setHistory(this.getHistory());
            }
            return doc;
        },

        linkedDoc: function(options) {
            if (!options) options = {};
            var from = this.first, to = this.first + this.size;
            if (options.from != null && options.from > from) from = options.from;
            if (options.to != null && options.to < to) to = options.to;
            var copy = new Doc(getLines(this, from, to), options.mode || this.modeOption, from);
            if (options.sharedHist) copy.history = this.history;
            (this.linked || (this.linked = [])).push({doc: copy, sharedHist: options.sharedHist});
            copy.linked = [{doc: this, isParent: true, sharedHist: options.sharedHist}];
            return copy;
        },
        unlinkDoc: function(other) {
            if (other instanceof CodeMirror) other = other.doc;
            if (this.linked) for (var i = 0; i < this.linked.length; ++i) {
                var link = this.linked[i];
                if (link.doc != other) continue;
                this.linked.splice(i, 1);
                other.unlinkDoc(this);
                break;
            }
            // If the histories were shared, split them again
            if (other.history == this.history) {
                var splitIds = [other.id];
                linkedDocs(other, function(doc) {splitIds.push(doc.id);}, true);
                other.history = makeHistory();
                other.history.done = copyHistoryArray(this.history.done, splitIds);
                other.history.undone = copyHistoryArray(this.history.undone, splitIds);
            }
        },
        iterLinkedDocs: function(f) {linkedDocs(this, f);},

        getMode: function() {return this.mode;},
        getEditor: function() {return this.cm;}
    });

    Doc.prototype.eachLine = Doc.prototype.iter;

    // The Doc methods that should be available on CodeMirror instances
    var dontDelegate = "iter insert remove copy getEditor".split(" ");
    for (var prop in Doc.prototype) if (Doc.prototype.hasOwnProperty(prop) && indexOf(dontDelegate, prop) < 0)
        CodeMirror.prototype[prop] = (function(method) {
            return function() {return method.apply(this.doc, arguments);};
        })(Doc.prototype[prop]);

    function linkedDocs(doc, f, sharedHistOnly) {
        function propagate(doc, skip, sharedHist) {
            if (doc.linked) for (var i = 0; i < doc.linked.length; ++i) {
                var rel = doc.linked[i];
                if (rel.doc == skip) continue;
                var shared = sharedHist && rel.sharedHist;
                if (sharedHistOnly && !shared) continue;
                f(rel.doc, shared);
                propagate(rel.doc, doc, shared);
            }
        }
        propagate(doc, null, true);
    }

    function attachDoc(cm, doc) {
        if (doc.cm) throw new Error("This document is already in use.");
        cm.doc = doc;
        doc.cm = cm;
        estimateLineHeights(cm);
        loadMode(cm);
        if (!cm.options.lineWrapping) computeMaxLength(cm);
        cm.options.mode = doc.modeOption;
        regChange(cm);
    }

    // LINE UTILITIES

    function getLine(chunk, n) {
        n -= chunk.first;
        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 getBetween(doc, start, end) {
        var out = [], n = start.line;
        doc.iter(start.line, end.line + 1, function(line) {
            var text = line.text;
            if (n == end.line) text = text.slice(0, end.ch);
            if (n == start.line) text = text.slice(start.ch);
            out.push(text);
            ++n;
        });
        return out;
    }
    function getLines(doc, from, to) {
        var out = [];
        doc.iter(from, to, function(line) { out.push(line.text); });
        return out;
    }

    function updateLineHeight(line, height) {
        var diff = height - line.height;
        for (var n = line; n; n = n.parent) n.height += diff;
    }

    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;; ++i) {
                if (chunk.children[i] == cur) break;
                no += chunk.children[i].chunkSize();
            }
        }
        return no + cur.first;
    }

    function lineAtHeight(chunk, h) {
        var n = chunk.first;
        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(cm, lineObj) {
        lineObj = visualLine(cm.doc, lineObj);

        var h = 0, chunk = lineObj.parent;
        for (var i = 0; i < chunk.lines.length; ++i) {
            var line = chunk.lines[i];
            if (line == lineObj) break;
            else h += line.height;
        }
        for (var p = chunk.parent; p; chunk = p, p = chunk.parent) {
            for (var i = 0; i < p.children.length; ++i) {
                var cur = p.children[i];
                if (cur == chunk) break;
                else h += cur.height;
            }
        }
        return h;
    }

    function getOrder(line) {
        var order = line.order;
        if (order == null) order = line.order = bidiOrdering(line.text);
        return order;
    }

    // HISTORY

    function makeHistory() {
        return {
            // Arrays of history events. Doing something adds an event to
            // done and clears undo. Undoing moves events from done to
            // undone, redoing moves them in the other direction.
            done: [], undone: [], undoDepth: Infinity,
            // Used to track when changes can be merged into a single undo
            // event
            lastTime: 0, lastOp: null, lastOrigin: null,
            // Used by the isClean() method
            dirtyCounter: 0
        };
    }

    function attachLocalSpans(doc, change, from, to) {
        var existing = change["spans_" + doc.id], n = 0;
        doc.iter(Math.max(doc.first, from), Math.min(doc.first + doc.size, to), function(line) {
            if (line.markedSpans)
                (existing || (existing = change["spans_" + doc.id] = {}))[n] = line.markedSpans;
            ++n;
        });
    }

    function historyChangeFromChange(doc, change) {
        var histChange = {from: change.from, to: changeEnd(change), text: getBetween(doc, change.from, change.to)};
        attachLocalSpans(doc, histChange, change.from.line, change.to.line + 1);
        linkedDocs(doc, function(doc) {attachLocalSpans(doc, histChange, change.from.line, change.to.line + 1);}, true);
        return histChange;
    }

    function addToHistory(doc, change, selAfter, opId) {
        var hist = doc.history;
        hist.undone.length = 0;
        var time = +new Date, cur = lst(hist.done);

        if (cur &&
            (hist.lastOp == opId ||
                hist.lastOrigin == change.origin && change.origin &&
                    ((change.origin.charAt(0) == "+" && hist.lastTime > time - 600) || change.origin.charAt(0) == "*"))) {
            // Merge this change into the last event
            var last = lst(cur.changes);
            if (posEq(change.from, change.to) && posEq(change.from, last.to)) {
                // Optimized case for simple insertion -- don't want to add
                // new changesets for every character typed
                last.to = changeEnd(change);
            } else {
                // Add new sub-event
                cur.changes.push(historyChangeFromChange(doc, change));
            }
            cur.anchorAfter = selAfter.anchor; cur.headAfter = selAfter.head;
        } else {
            // Can not be merged, start a new event.
            cur = {changes: [historyChangeFromChange(doc, change)],
                anchorBefore: doc.sel.anchor, headBefore: doc.sel.head,
                anchorAfter: selAfter.anchor, headAfter: selAfter.head};
            hist.done.push(cur);
            while (hist.done.length > hist.undoDepth)
                hist.done.shift();
            if (hist.dirtyCounter < 0)
            // The user has made a change after undoing past the last clean state. 
            // We can never get back to a clean state now until markClean() is called.
                hist.dirtyCounter = NaN;
            else
                hist.dirtyCounter++;
        }
        hist.lastTime = time;
        hist.lastOp = opId;
        hist.lastOrigin = change.origin;
    }

    function removeClearedSpans(spans) {
        if (!spans) return null;
        for (var i = 0, out; i < spans.length; ++i) {
            if (spans[i].marker.explicitlyCleared) { if (!out) out = spans.slice(0, i); }
            else if (out) out.push(spans[i]);
        }
        return !out ? spans : out.length ? out : null;
    }

    function getOldSpans(doc, change) {
        var found = change["spans_" + doc.id];
        if (!found) return null;
        for (var i = 0, nw = []; i < change.text.length; ++i)
            nw.push(removeClearedSpans(found[i]));
        return nw;
    }

    // Used both to provide a JSON-safe object in .getHistory, and, when
    // detaching a document, to split the history in two
    function copyHistoryArray(events, newGroup) {
        for (var i = 0, copy = []; i < events.length; ++i) {
            var event = events[i], changes = event.changes, newChanges = [];
            copy.push({changes: newChanges, anchorBefore: event.anchorBefore, headBefore: event.headBefore,
                anchorAfter: event.anchorAfter, headAfter: event.headAfter});
            for (var j = 0; j < changes.length; ++j) {
                var change = changes[j], m;
                newChanges.push({from: change.from, to: change.to, text: change.text});
                if (newGroup) for (var prop in change) if (m = prop.match(/^spans_(\d+)$/)) {
                    if (indexOf(newGroup, Number(m[1])) > -1) {
                        lst(newChanges)[prop] = change[prop];
                        delete change[prop];
                    }
                }
            }
        }
        return copy;
    }

    // Rebasing/resetting history to deal with externally-sourced changes

    function rebaseHistSel(pos, from, to, diff) {
        if (to < pos.line) {
            pos.line += diff;
        } else if (from < pos.line) {
            pos.line = from;
            pos.ch = 0;
        }
    }

    // Tries to rebase an array of history events given a change in the
    // document. If the change touches the same lines as the event, the
    // event, and everything 'behind' it, is discarded. If the change is
    // before the event, the event's positions are updated. Uses a
    // copy-on-write scheme for the positions, to avoid having to
    // reallocate them all on every rebase, but also avoid problems with
    // shared position objects being unsafely updated.
    function rebaseHistArray(array, from, to, diff) {
        for (var i = 0; i < array.length; ++i) {
            var sub = array[i], ok = true;
            for (var j = 0; j < sub.changes.length; ++j) {
                var cur = sub.changes[j];
                if (!sub.copied) { cur.from = copyPos(cur.from); cur.to = copyPos(cur.to); }
                if (to < cur.from.line) {
                    cur.from.line += diff;
                    cur.to.line += diff;
                } else if (from <= cur.to.line) {
                    ok = false;
                    break;
                }
            }
            if (!sub.copied) {
                sub.anchorBefore = copyPos(sub.anchorBefore); sub.headBefore = copyPos(sub.headBefore);
                sub.anchorAfter = copyPos(sub.anchorAfter); sub.readAfter = copyPos(sub.headAfter);
                sub.copied = true;
            }
            if (!ok) {
                array.splice(0, i + 1);
                i = 0;
            } else {
                rebaseHistSel(sub.anchorBefore); rebaseHistSel(sub.headBefore);
                rebaseHistSel(sub.anchorAfter); rebaseHistSel(sub.headAfter);
            }
        }
    }

    function rebaseHist(hist, change) {
        var from = change.from.line, to = change.to.line, diff = change.text.length - (to - from) - 1;
        rebaseHistArray(hist.done, from, to, diff);
        rebaseHistArray(hist.undone, from, to, diff);
    }

    // EVENT OPERATORS

    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) {
        var b = e.which;
        if (b == null) {
            if (e.button & 1) b = 1;
            else if (e.button & 2) b = 3;
            else if (e.button & 4) b = 2;
        }
        if (mac && e.ctrlKey && b == 1) b = 3;
        return b;
    }

    // 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 HANDLING

    function on(emitter, type, f) {
        if (emitter.addEventListener)
            emitter.addEventListener(type, f, false);
        else if (emitter.attachEvent)
            emitter.attachEvent("on" + type, f);
        else {
            var map = emitter._handlers || (emitter._handlers = {});
            var arr = map[type] || (map[type] = []);
            arr.push(f);
        }
    }

    function off(emitter, type, f) {
        if (emitter.removeEventListener)
            emitter.removeEventListener(type, f, false);
        else if (emitter.detachEvent)
            emitter.detachEvent("on" + type, f);
        else {
            var arr = emitter._handlers && emitter._handlers[type];
            if (!arr) return;
            for (var i = 0; i < arr.length; ++i)
                if (arr[i] == f) { arr.splice(i, 1); break; }
        }
    }

    function signal(emitter, type /*, values...*/) {
        var arr = emitter._handlers && emitter._handlers[type];
        if (!arr) return;
        var args = Array.prototype.slice.call(arguments, 2);
        for (var i = 0; i < arr.length; ++i) arr[i].apply(null, args);
    }

    var delayedCallbacks, delayedCallbackDepth = 0;
    function signalLater(emitter, type /*, values...*/) {
        var arr = emitter._handlers && emitter._handlers[type];
        if (!arr) return;
        var args = Array.prototype.slice.call(arguments, 2);
        if (!delayedCallbacks) {
            ++delayedCallbackDepth;
            delayedCallbacks = [];
            setTimeout(fireDelayed, 0);
        }
        function bnd(f) {return function(){f.apply(null, args);};};
        for (var i = 0; i < arr.length; ++i)
            delayedCallbacks.push(bnd(arr[i]));
    }

    function fireDelayed() {
        --delayedCallbackDepth;
        var delayed = delayedCallbacks;
        delayedCallbacks = null;
        for (var i = 0; i < delayed.length; ++i) delayed[i]();
    }

    function hasHandler(emitter, type) {
        var arr = emitter._handlers && emitter._handlers[type];
        return arr && arr.length > 0;
    }

    CodeMirror.on = on; CodeMirror.off = off; CodeMirror.signal = signal;

    // MISC UTILITIES

    // Number of pixels added to scroller and sizer to hide scrollbar
    var scrollerCutOff = 30;

    // Returned or thrown by various protocols to signal 'I'm not
    // handling this'.
    var Pass = CodeMirror.Pass = {toString: function(){return "CodeMirror.Pass";}};

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

    // 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;
    }
    CodeMirror.countColumn = countColumn;

    var spaceStrs = [""];
    function spaceStr(n) {
        while (spaceStrs.length <= n)
            spaceStrs.push(lst(spaceStrs) + " ");
        return spaceStrs[n];
    }

    function lst(arr) { return arr[arr.length-1]; }

    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();
    }

    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 createObj(base, props) {
        function Obj() {}
        Obj.prototype = base;
        var inst = new Obj();
        if (props) copyObj(props, inst);
        return inst;
    }

    function copyObj(obj, target) {
        if (!target) target = {};
        for (var prop in obj) if (obj.hasOwnProperty(prop)) target[prop] = obj[prop];
        return target;
    }

    function emptyArray(size) {
        for (var a = [], i = 0; i < size; ++i) a.push(undefined);
        return a;
    }

    function bind(f) {
        var args = Array.prototype.slice.call(arguments, 1);
        return function(){return f.apply(null, args);};
    }

    var nonASCIISingleCaseWordChar = /[\u3040-\u309f\u30a0-\u30ff\u3400-\u4db5\u4e00-\u9fcc]/;
    function isWordChar(ch) {
        return /\w/.test(ch) || ch > "\x80" &&
            (ch.toUpperCase() != ch.toLowerCase() || nonASCIISingleCaseWordChar.test(ch));
    }

    function isEmpty(obj) {
        for (var n in obj) if (obj.hasOwnProperty(n) && obj[n]) return false;
        return true;
    }

    var isExtendingChar = /[\u0300-\u036F\u0483-\u0487\u0488-\u0489\u0591-\u05BD\u05BF\u05C1-\u05C2\u05C4-\u05C5\u05C7\u0610-\u061A\u064B-\u065F\u0670\u06D6-\u06DC\u06DF-\u06E4\u06E7-\u06E8\u06EA-\u06ED\uA66F\uA670-\uA672\uA674-\uA67D\uA69F\udc00-\udfff]/;

    // DOM UTILITIES

    function elt(tag, content, className, style) {
        var e = document.createElement(tag);
        if (className) e.className = className;
        if (style) e.style.cssText = style;
        if (typeof content == "string") setTextContent(e, content);
        else if (content) for (var i = 0; i < content.length; ++i) e.appendChild(content[i]);
        return e;
    }

    function removeChildren(e) {
        // IE will break all parent-child relations in subnodes when setting innerHTML
        if (!ie) e.innerHTML = "";
        else while (e.firstChild) e.removeChild(e.firstChild);
        return e;
    }

    function removeChildrenAndAdd(parent, e) {
        return removeChildren(parent).appendChild(e);
    }

    function setTextContent(e, str) {
        if (ie_lt9) {
            e.innerHTML = "";
            e.appendChild(document.createTextNode(str));
        } else e.textContent = str;
    }

    function getPixelRect(node) { return node.getBoundingClientRect();}
    function getLogicalRect(node) { return node.getBoundingClientRect();}
    CodeMirror.replacePixelRect = function(f) { getPixelRect = f; };
    CodeMirror.replaceLogicalRect = function(f) { getLogicalRect = f; };

    // FEATURE DETECTION

    // Detect drag-and-drop
    var dragAndDrop = function() {
        // There is *some* kind of drag-and-drop support in IE6-8, but I
        // couldn't get it to work yet.
        if (ie_lt9) return false;
        var div = elt('div');
        return "draggable" in div || "dragDrop" in div;
    }();

    // For a reason I have yet to figure out, some browsers disallow
    // word wrapping between certain characters *only* if a new inline
    // element is started between them. This makes it hard to reliably
    // measure the position of things, since that requires inserting an
    // extra span. This terribly fragile set of regexps matches the
    // character combinations that suffer from this phenomenon on the
    // various browsers.
    var spanAffectsWrapping = /^$/; // Won't match any two-character string
    if (gecko) spanAffectsWrapping = /$'/;
    else if (safari) spanAffectsWrapping = /\-[^ \-?]|\?[^ !'\"\),.\-\/:;\?\]\}]/;
    else if (chrome) spanAffectsWrapping = /\-[^ \-\.?]|\?[^ \-\.?\]\}:;!'\"\),\/]|[\.!\"#&%\)*+,:;=>\]|\}~][\(\{\[<]|\$'/;

    var knownScrollbarWidth;
    function scrollbarWidth(measure) {
        if (knownScrollbarWidth != null) return knownScrollbarWidth;
        var test = elt("div", null, null, "width: 50px; height: 50px; overflow-x: scroll");
        removeChildrenAndAdd(measure, test);
        if (test.offsetWidth)
            knownScrollbarWidth = test.offsetHeight - test.clientHeight;
        return knownScrollbarWidth || 0;
    }

    var zwspSupported;
    function zeroWidthElement(measure) {
        if (zwspSupported == null) {
            var test = elt("span", "\u200b");
            removeChildrenAndAdd(measure, elt("span", [test, document.createTextNode("x")]));
            if (measure.firstChild.offsetHeight != 0)
                zwspSupported = test.offsetWidth <= 1 && test.offsetHeight > 2 && !ie_lt8;
        }
        if (zwspSupported) return elt("span", "\u200b");
        else return elt("span", "\u00a0", null, "display: inline-block; width: 1px; margin-right: -1px");
    }

    // 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, result = [], l = string.length;
        while (pos <= l) {
            var nl = string.indexOf("\n", pos);
            if (nl == -1) nl = string.length;
            var line = string.slice(pos, string.charAt(nl - 1) == "\r" ? nl - 1 : nl);
            var rt = line.indexOf("\r");
            if (rt != -1) {
                result.push(line.slice(0, rt));
                pos += rt + 1;
            } else {
                result.push(line);
                pos = nl + 1;
            }
        }
        return result;
    } : function(string){return string.split(/\r\n?|\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;
    };

    var hasCopyEvent = (function() {
        var e = elt("div");
        if ("oncopy" in e) return true;
        e.setAttribute("oncopy", "return;");
        return typeof e.oncopy == 'function';
    })();

    // KEY NAMING

    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", 109: "-", 107: "=", 127: "Delete",
        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;
    })();

    // BIDI HELPERS

    function iterateBidiSections(order, from, to, f) {
        if (!order) return f(from, to, "ltr");
        for (var i = 0; i < order.length; ++i) {
            var part = order[i];
            if (part.from < to && part.to > from || from == to && part.to == from)
                f(Math.max(part.from, from), Math.min(part.to, to), part.level == 1 ? "rtl" : "ltr");
        }
    }

    function bidiLeft(part) { return part.level % 2 ? part.to : part.from; }
    function bidiRight(part) { return part.level % 2 ? part.from : part.to; }

    function lineLeft(line) { var order = getOrder(line); return order ? bidiLeft(order[0]) : 0; }
    function lineRight(line) {
        var order = getOrder(line);
        if (!order) return line.text.length;
        return bidiRight(lst(order));
    }

    function lineStart(cm, lineN) {
        var line = getLine(cm.doc, lineN);
        var visual = visualLine(cm.doc, line);
        if (visual != line) lineN = lineNo(visual);
        var order = getOrder(visual);
        var ch = !order ? 0 : order[0].level % 2 ? lineRight(visual) : lineLeft(visual);
        return Pos(lineN, ch);
    }
    function lineEnd(cm, lineN) {
        var merged, line;
        while (merged = collapsedSpanAtEnd(line = getLine(cm.doc, lineN)))
            lineN = merged.find().to.line;
        var order = getOrder(line);
        var ch = !order ? line.text.length : order[0].level % 2 ? lineLeft(line) : lineRight(line);
        return Pos(lineN, ch);
    }

    // This is somewhat involved. It is needed in order to move
    // 'visually' through bi-directional text -- i.e., pressing left
    // should make the cursor go left, even when in RTL text. The
    // tricky part is the 'jumps', where RTL and LTR text touch each
    // other. This often requires the cursor offset to move more than
    // one unit, in order to visually move one unit.
    function moveVisually(line, start, dir, byUnit) {
        var bidi = getOrder(line);
        if (!bidi) return moveLogically(line, start, dir, byUnit);
        var moveOneUnit = byUnit ? function(pos, dir) {
            do pos += dir;
            while (pos > 0 && isExtendingChar.test(line.text.charAt(pos)));
            return pos;
        } : function(pos, dir) { return pos + dir; };
        var linedir = bidi[0].level;
        for (var i = 0; i < bidi.length; ++i) {
            var part = bidi[i], sticky = part.level % 2 == linedir;
            if ((part.from < start && part.to > start) ||
                (sticky && (part.from == start || part.to == start))) break;
        }
        var target = moveOneUnit(start, part.level % 2 ? -dir : dir);

        while (target != null) {
            if (part.level % 2 == linedir) {
                if (target < part.from || target > part.to) {
                    part = bidi[i += dir];
                    target = part && (dir > 0 == part.level % 2 ? moveOneUnit(part.to, -1) : moveOneUnit(part.from, 1));
                } else break;
            } else {
                if (target == bidiLeft(part)) {
                    part = bidi[--i];
                    target = part && bidiRight(part);
                } else if (target == bidiRight(part)) {
                    part = bidi[++i];
                    target = part && bidiLeft(part);
                } else break;
            }
        }

        return target < 0 || target > line.text.length ? null : target;
    }

    function moveLogically(line, start, dir, byUnit) {
        var target = start + dir;
        if (byUnit) while (target > 0 && isExtendingChar.test(line.text.charAt(target))) target += dir;
        return target < 0 || target > line.text.length ? null : target;
    }


    // 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;



    // Bidirectional ordering algorithm
    // See http://unicode.org/reports/tr9/tr9-13.html for the algorithm
    // that this (partially) implements.

    // One-char codes used for character types:
    // L (L):   Left-to-Right
    // R (R):   Right-to-Left
    // r (AL):  Right-to-Left Arabic
    // 1 (EN):  European Number
    // + (ES):  European Number Separator
    // % (ET):  European Number Terminator
    // n (AN):  Arabic Number
    // , (CS):  Common Number Separator
    // m (NSM): Non-Spacing Mark
    // b (BN):  Boundary Neutral
    // s (B):   Paragraph Separator
    // t (S):   Segment Separator
    // w (WS):  Whitespace
    // N (ON):  Other Neutrals

    // Returns null if characters are ordered as they appear
    // (left-to-right), or an array of sections ({from, to, level}
    // objects) in the order in which they occur visually.
    var bidiOrdering = (function() {
        // Character types for codepoints 0 to 0xff
        var lowTypes = "bbbbbbbbbtstwsbbbbbbbbbbbbbbssstwNN%%%NNNNNN,N,N1111111111NNNNNNNLLLLLLLLLLLLLLLLLLLLLLLLLLNNNNNNLLLLLLLLLLLLLLLLLLLLLLLLLLNNNNbbbbbbsbbbbbbbbbbbbbbbbbbbbbbbbbb,N%%%%NNNNLNNNNN%%11NLNNN1LNNNNNLLLLLLLLLLLLLLLLLLLLLLLNLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLNLLLLLLLL";
        // Character types for codepoints 0x600 to 0x6ff
        var arabicTypes = "rrrrrrrrrrrr,rNNmmmmmmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmrrrrrrrnnnnnnnnnn%nnrrrmrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrmmmmmmmmmmmmmmmmmmmNmmmmrrrrrrrrrrrrrrrrrr";
        function charType(code) {
            if (code <= 0xff) return lowTypes.charAt(code);
            else if (0x590 <= code && code <= 0x5f4) return "R";
            else if (0x600 <= code && code <= 0x6ff) return arabicTypes.charAt(code - 0x600);
            else if (0x700 <= code && code <= 0x8ac) return "r";
            else return "L";
        }

        var bidiRE = /[\u0590-\u05f4\u0600-\u06ff\u0700-\u08ac]/;
        var isNeutral = /[stwN]/, isStrong = /[LRr]/, countsAsLeft = /[Lb1n]/, countsAsNum = /[1n]/;
        // Browsers seem to always treat the boundaries of block elements as being L.
        var outerType = "L";

        return function(str) {
            if (!bidiRE.test(str)) return false;
            var len = str.length, types = [];
            for (var i = 0, type; i < len; ++i)
                types.push(type = charType(str.charCodeAt(i)));

            // W1. Examine each non-spacing mark (NSM) in the level run, and
            // change the type of the NSM to the type of the previous
            // character. If the NSM is at the start of the level run, it will
            // get the type of sor.
            for (var i = 0, prev = outerType; i < len; ++i) {
                var type = types[i];
                if (type == "m") types[i] = prev;
                else prev = type;
            }

            // W2. Search backwards from each instance of a European number
            // until the first strong type (R, L, AL, or sor) is found. If an
            // AL is found, change the type of the European number to Arabic
            // number.
            // W3. Change all ALs to R.
            for (var i = 0, cur = outerType; i < len; ++i) {
                var type = types[i];
                if (type == "1" && cur == "r") types[i] = "n";
                else if (isStrong.test(type)) { cur = type; if (type == "r") types[i] = "R"; }
            }

            // W4. A single European separator between two European numbers
            // changes to a European number. A single common separator between
            // two numbers of the same type changes to that type.
            for (var i = 1, prev = types[0]; i < len - 1; ++i) {
                var type = types[i];
                if (type == "+" && prev == "1" && types[i+1] == "1") types[i] = "1";
                else if (type == "," && prev == types[i+1] &&
                    (prev == "1" || prev == "n")) types[i] = prev;
                prev = type;
            }

            // W5. A sequence of European terminators adjacent to European
            // numbers changes to all European numbers.
            // W6. Otherwise, separators and terminators change to Other
            // Neutral.
            for (var i = 0; i < len; ++i) {
                var type = types[i];
                if (type == ",") types[i] = "N";
                else if (type == "%") {
                    for (var end = i + 1; end < len && types[end] == "%"; ++end) {}
                    var replace = (i && types[i-1] == "!") || (end < len - 1 && types[end] == "1") ? "1" : "N";
                    for (var j = i; j < end; ++j) types[j] = replace;
                    i = end - 1;
                }
            }

            // W7. Search backwards from each instance of a European number
            // until the first strong type (R, L, or sor) is found. If an L is
            // found, then change the type of the European number to L.
            for (var i = 0, cur = outerType; i < len; ++i) {
                var type = types[i];
                if (cur == "L" && type == "1") types[i] = "L";
                else if (isStrong.test(type)) cur = type;
            }

            // N1. A sequence of neutrals takes the direction of the
            // surrounding strong text if the text on both sides has the same
            // direction. European and Arabic numbers act as if they were R in
            // terms of their influence on neutrals. Start-of-level-run (sor)
            // and end-of-level-run (eor) are used at level run boundaries.
            // N2. Any remaining neutrals take the embedding direction.
            for (var i = 0; i < len; ++i) {
                if (isNeutral.test(types[i])) {
                    for (var end = i + 1; end < len && isNeutral.test(types[end]); ++end) {}
                    var before = (i ? types[i-1] : outerType) == "L";
                    var after = (end < len - 1 ? types[end] : outerType) == "L";
                    var replace = before || after ? "L" : "R";
                    for (var j = i; j < end; ++j) types[j] = replace;
                    i = end - 1;
                }
            }

            // Here we depart from the documented algorithm, in order to avoid
            // building up an actual levels array. Since there are only three
            // levels (0, 1, 2) in an implementation that doesn't take
            // explicit embedding into account, we can build up the order on
            // the fly, without following the level-based algorithm.
            var order = [], m;
            for (var i = 0; i < len;) {
                if (countsAsLeft.test(types[i])) {
                    var start = i;
                    for (++i; i < len && countsAsLeft.test(types[i]); ++i) {}
                    order.push({from: start, to: i, level: 0});
                } else {
                    var pos = i, at = order.length;
                    for (++i; i < len && types[i] != "L"; ++i) {}
                    for (var j = pos; j < i;) {
                        if (countsAsNum.test(types[j])) {
                            if (pos < j) order.splice(at, 0, {from: pos, to: j, level: 1});
                            var nstart = j;
                            for (++j; j < i && countsAsNum.test(types[j]); ++j) {}
                            order.splice(at, 0, {from: nstart, to: j, level: 2});
                            pos = j;
                        } else ++j;
                    }
                    if (pos < i) order.splice(at, 0, {from: pos, to: i, level: 1});
                }
            }
            if (order[0].level == 1 && (m = str.match(/^\s+/))) {
                order[0].from = m[0].length;
                order.unshift({from: 0, to: m[0].length, level: 0});
            }
            if (lst(order).level == 1 && (m = str.match(/\s+$/))) {
                lst(order).to -= m[0].length;
                order.push({from: len - m[0].length, to: len, level: 0});
            }
            if (order[0].level != lst(order).level)
                order.push({from: len, to: len, level: order[0].level});

            return order;
        };
    })();

    // THE END

    CodeMirror.version = "3.02 +";

    return CodeMirror;
})();
