Proyectos de Subversion Moodle

/**

The data structure for documents. @nonabstract

*/

class Text {

    /**

    Get the line description around the given position.

    */

    lineAt(pos) {

        if (pos < 0 || pos > this.length)

            throw new RangeError(`Invalid position ${pos} in document of length ${this.length}`);

        return this.lineInner(pos, false, 1, 0);

    }

    /**

    Get the description for the given (1-based) line number.

    */

    line(n) {

        if (n < 1 || n > this.lines)

            throw new RangeError(`Invalid line number ${n} in ${this.lines}-line document`);

        return this.lineInner(n, true, 1, 0);

    }

    /**

    Replace a range of the text with the given content.

    */

    replace(from, to, text) {

        [from, to] = clip(this, from, to);

        let parts = [];

        this.decompose(0, from, parts, 2 /* Open.To */);

        if (text.length)

            text.decompose(0, text.length, parts, 1 /* Open.From */ | 2 /* Open.To */);

        this.decompose(to, this.length, parts, 1 /* Open.From */);

        return TextNode.from(parts, this.length - (to - from) + text.length);

    }

    /**

    Append another document to this one.

    */

    append(other) {

        return this.replace(this.length, this.length, other);

    }

    /**

    Retrieve the text between the given points.

    */

    slice(from, to = this.length) {

        [from, to] = clip(this, from, to);

        let parts = [];

        this.decompose(from, to, parts, 0);

        return TextNode.from(parts, to - from);

    }

    /**

    Test whether this text is equal to another instance.

    */

    eq(other) {

        if (other == this)

            return true;

        if (other.length != this.length || other.lines != this.lines)

            return false;

        let start = this.scanIdentical(other, 1), end = this.length - this.scanIdentical(other, -1);

        let a = new RawTextCursor(this), b = new RawTextCursor(other);

        for (let skip = start, pos = start;;) {

            a.next(skip);

            b.next(skip);

            skip = 0;

            if (a.lineBreak != b.lineBreak || a.done != b.done || a.value != b.value)

                return false;

            pos += a.value.length;

            if (a.done || pos >= end)

                return true;

        }

    }

    /**

    Iterate over the text. When `dir` is `-1`, iteration happens

    from end to start. This will return lines and the breaks between

    them as separate strings.

    */

    iter(dir = 1) { return new RawTextCursor(this, dir); }

    /**

    Iterate over a range of the text. When `from` > `to`, the

    iterator will run in reverse.

    */

    iterRange(from, to = this.length) { return new PartialTextCursor(this, from, to); }

    /**

    Return a cursor that iterates over the given range of lines,

    _without_ returning the line breaks between, and yielding empty

    strings for empty lines.

    When `from` and `to` are given, they should be 1-based line numbers.

    */

    iterLines(from, to) {

        let inner;

        if (from == null) {

            inner = this.iter();

        }

        else {

            if (to == null)

                to = this.lines + 1;

            let start = this.line(from).from;

            inner = this.iterRange(start, Math.max(start, to == this.lines + 1 ? this.length : to <= 1 ? 0 : this.line(to - 1).to));

        }

        return new LineCursor(inner);

    }

    /**

    Return the document as a string, using newline characters to

    separate lines.

    */

    toString() { return this.sliceString(0); }

    /**

    Convert the document to an array of lines (which can be

    deserialized again via [`Text.of`](https://codemirror.net/6/docs/ref/#state.Text^of)).

    */

    toJSON() {

        let lines = [];

        this.flatten(lines);

        return lines;

    }

    /**

    @internal

    */

    constructor() { }

    /**

    Create a `Text` instance for the given array of lines.

    */

    static of(text) {

        if (text.length == 0)

            throw new RangeError("A document must have at least one line");

        if (text.length == 1 && !text[0])

            return Text.empty;

        return text.length <= 32 /* Tree.Branch */ ? new TextLeaf(text) : TextNode.from(TextLeaf.split(text, []));

    }

}

// Leaves store an array of line strings. There are always line breaks

// between these strings. Leaves are limited in size and have to be

// contained in TextNode instances for bigger documents.

class TextLeaf extends Text {

    constructor(text, length = textLength(text)) {

        super();

        this.text = text;

        this.length = length;

    }

    get lines() { return this.text.length; }

    get children() { return null; }

    lineInner(target, isLine, line, offset) {

        for (let i = 0;; i++) {

            let string = this.text[i], end = offset + string.length;

            if ((isLine ? line : end) >= target)

                return new Line(offset, end, line, string);

            offset = end + 1;

            line++;

        }

    }

    decompose(from, to, target, open) {

        let text = from <= 0 && to >= this.length ? this

            : new TextLeaf(sliceText(this.text, from, to), Math.min(to, this.length) - Math.max(0, from));

        if (open & 1 /* Open.From */) {

            let prev = target.pop();

            let joined = appendText(text.text, prev.text.slice(), 0, text.length);

            if (joined.length <= 32 /* Tree.Branch */) {

                target.push(new TextLeaf(joined, prev.length + text.length));

            }

            else {

                let mid = joined.length >> 1;

                target.push(new TextLeaf(joined.slice(0, mid)), new TextLeaf(joined.slice(mid)));

            }

        }

        else {

            target.push(text);

        }

    }

    replace(from, to, text) {

        if (!(text instanceof TextLeaf))

            return super.replace(from, to, text);

        [from, to] = clip(this, from, to);

        let lines = appendText(this.text, appendText(text.text, sliceText(this.text, 0, from)), to);

        let newLen = this.length + text.length - (to - from);

        if (lines.length <= 32 /* Tree.Branch */)

            return new TextLeaf(lines, newLen);

        return TextNode.from(TextLeaf.split(lines, []), newLen);

    }

    sliceString(from, to = this.length, lineSep = "\n") {

        [from, to] = clip(this, from, to);

        let result = "";

        for (let pos = 0, i = 0; pos <= to && i < this.text.length; i++) {

            let line = this.text[i], end = pos + line.length;

            if (pos > from && i)

                result += lineSep;

            if (from < end && to > pos)

                result += line.slice(Math.max(0, from - pos), to - pos);

            pos = end + 1;

        }

        return result;

    }

    flatten(target) {

        for (let line of this.text)

            target.push(line);

    }

    scanIdentical() { return 0; }

    static split(text, target) {

        let part = [], len = -1;

        for (let line of text) {

            part.push(line);

            len += line.length + 1;

            if (part.length == 32 /* Tree.Branch */) {

                target.push(new TextLeaf(part, len));

                part = [];

                len = -1;

            }

        }

        if (len > -1)

            target.push(new TextLeaf(part, len));

        return target;

    }

}

// Nodes provide the tree structure of the `Text` type. They store a

// number of other nodes or leaves, taking care to balance themselves

// on changes. There are implied line breaks _between_ the children of

// a node (but not before the first or after the last child).

class TextNode extends Text {

    constructor(children, length) {

        super();

        this.children = children;

        this.length = length;

        this.lines = 0;

        for (let child of children)

            this.lines += child.lines;

    }

    lineInner(target, isLine, line, offset) {

        for (let i = 0;; i++) {

            let child = this.children[i], end = offset + child.length, endLine = line + child.lines - 1;

            if ((isLine ? endLine : end) >= target)

                return child.lineInner(target, isLine, line, offset);

            offset = end + 1;

            line = endLine + 1;

        }

    }

    decompose(from, to, target, open) {

        for (let i = 0, pos = 0; pos <= to && i < this.children.length; i++) {

            let child = this.children[i], end = pos + child.length;

            if (from <= end && to >= pos) {

                let childOpen = open & ((pos <= from ? 1 /* Open.From */ : 0) | (end >= to ? 2 /* Open.To */ : 0));

                if (pos >= from && end <= to && !childOpen)

                    target.push(child);

                else

                    child.decompose(from - pos, to - pos, target, childOpen);

            }

            pos = end + 1;

        }

    }

    replace(from, to, text) {

        [from, to] = clip(this, from, to);

        if (text.lines < this.lines)

            for (let i = 0, pos = 0; i < this.children.length; i++) {

                let child = this.children[i], end = pos + child.length;

                // Fast path: if the change only affects one child and the

                // child's size remains in the acceptable range, only update

                // that child

                if (from >= pos && to <= end) {

                    let updated = child.replace(from - pos, to - pos, text);

                    let totalLines = this.lines - child.lines + updated.lines;

                    if (updated.lines < (totalLines >> (5 /* Tree.BranchShift */ - 1)) &&

                        updated.lines > (totalLines >> (5 /* Tree.BranchShift */ + 1))) {

                        let copy = this.children.slice();

                        copy[i] = updated;

                        return new TextNode(copy, this.length - (to - from) + text.length);

                    }

                    return super.replace(pos, end, updated);

                }

                pos = end + 1;

            }

        return super.replace(from, to, text);

    }

    sliceString(from, to = this.length, lineSep = "\n") {

        [from, to] = clip(this, from, to);

        let result = "";

        for (let i = 0, pos = 0; i < this.children.length && pos <= to; i++) {

            let child = this.children[i], end = pos + child.length;

            if (pos > from && i)

                result += lineSep;

            if (from < end && to > pos)

                result += child.sliceString(from - pos, to - pos, lineSep);

            pos = end + 1;

        }

        return result;

    }

    flatten(target) {

        for (let child of this.children)

            child.flatten(target);

    }

    scanIdentical(other, dir) {

        if (!(other instanceof TextNode))

            return 0;

        let length = 0;

        let [iA, iB, eA, eB] = dir > 0 ? [0, 0, this.children.length, other.children.length]

            : [this.children.length - 1, other.children.length - 1, -1, -1];

        for (;; iA += dir, iB += dir) {

            if (iA == eA || iB == eB)

                return length;

            let chA = this.children[iA], chB = other.children[iB];

            if (chA != chB)

                return length + chA.scanIdentical(chB, dir);

            length += chA.length + 1;

        }

    }

    static from(children, length = children.reduce((l, ch) => l + ch.length + 1, -1)) {

        let lines = 0;

        for (let ch of children)

            lines += ch.lines;

        if (lines < 32 /* Tree.Branch */) {

            let flat = [];

            for (let ch of children)

                ch.flatten(flat);

            return new TextLeaf(flat, length);

        }

        let chunk = Math.max(32 /* Tree.Branch */, lines >> 5 /* Tree.BranchShift */), maxChunk = chunk << 1, minChunk = chunk >> 1;

        let chunked = [], currentLines = 0, currentLen = -1, currentChunk = [];

        function add(child) {

            let last;

            if (child.lines > maxChunk && child instanceof TextNode) {

                for (let node of child.children)

                    add(node);

            }

            else if (child.lines > minChunk && (currentLines > minChunk || !currentLines)) {

                flush();

                chunked.push(child);

            }

            else if (child instanceof TextLeaf && currentLines &&

                (last = currentChunk[currentChunk.length - 1]) instanceof TextLeaf &&

                child.lines + last.lines <= 32 /* Tree.Branch */) {

                currentLines += child.lines;

                currentLen += child.length + 1;

                currentChunk[currentChunk.length - 1] = new TextLeaf(last.text.concat(child.text), last.length + 1 + child.length);

            }

            else {

                if (currentLines + child.lines > chunk)

                    flush();

                currentLines += child.lines;

                currentLen += child.length + 1;

                currentChunk.push(child);

            }

        }

        function flush() {

            if (currentLines == 0)

                return;

            chunked.push(currentChunk.length == 1 ? currentChunk[0] : TextNode.from(currentChunk, currentLen));

            currentLen = -1;

            currentLines = currentChunk.length = 0;

        }

        for (let child of children)

            add(child);

        flush();

        return chunked.length == 1 ? chunked[0] : new TextNode(chunked, length);

    }

}

Text.empty = /*@__PURE__*/new TextLeaf([""], 0);

function textLength(text) {

    let length = -1;

    for (let line of text)

        length += line.length + 1;

    return length;

}

function appendText(text, target, from = 0, to = 1e9) {

    for (let pos = 0, i = 0, first = true; i < text.length && pos <= to; i++) {

        let line = text[i], end = pos + line.length;

        if (end >= from) {

            if (end > to)

                line = line.slice(0, to - pos);

            if (pos < from)

                line = line.slice(from - pos);

            if (first) {

                target[target.length - 1] += line;

                first = false;

            }

            else

                target.push(line);

        }

        pos = end + 1;

    }

    return target;

}

function sliceText(text, from, to) {

    return appendText(text, [""], from, to);

}

class RawTextCursor {

    constructor(text, dir = 1) {

        this.dir = dir;

        this.done = false;

        this.lineBreak = false;

        this.value = "";

        this.nodes = [text];

        this.offsets = [dir > 0 ? 1 : (text instanceof TextLeaf ? text.text.length : text.children.length) << 1];

    }

    nextInner(skip, dir) {

        this.done = this.lineBreak = false;

        for (;;) {

            let last = this.nodes.length - 1;

            let top = this.nodes[last], offsetValue = this.offsets[last], offset = offsetValue >> 1;

            let size = top instanceof TextLeaf ? top.text.length : top.children.length;

            if (offset == (dir > 0 ? size : 0)) {

                if (last == 0) {

                    this.done = true;

                    this.value = "";

                    return this;

                }

                if (dir > 0)

                    this.offsets[last - 1]++;

                this.nodes.pop();

                this.offsets.pop();

            }

            else if ((offsetValue & 1) == (dir > 0 ? 0 : 1)) {

                this.offsets[last] += dir;

                if (skip == 0) {

                    this.lineBreak = true;

                    this.value = "\n";

                    return this;

                }

                skip--;

            }

            else if (top instanceof TextLeaf) {

                // Move to the next string

                let next = top.text[offset + (dir < 0 ? -1 : 0)];

                this.offsets[last] += dir;

                if (next.length > Math.max(0, skip)) {

                    this.value = skip == 0 ? next : dir > 0 ? next.slice(skip) : next.slice(0, next.length - skip);

                    return this;

                }

                skip -= next.length;

            }

            else {

                let next = top.children[offset + (dir < 0 ? -1 : 0)];

                if (skip > next.length) {

                    skip -= next.length;

                    this.offsets[last] += dir;

                }

                else {

                    if (dir < 0)

                        this.offsets[last]--;

                    this.nodes.push(next);

                    this.offsets.push(dir > 0 ? 1 : (next instanceof TextLeaf ? next.text.length : next.children.length) << 1);

                }

            }

        }

    }

    next(skip = 0) {

        if (skip < 0) {

            this.nextInner(-skip, (-this.dir));

            skip = this.value.length;

        }

        return this.nextInner(skip, this.dir);

    }

}

class PartialTextCursor {

    constructor(text, start, end) {

        this.value = "";

        this.done = false;

        this.cursor = new RawTextCursor(text, start > end ? -1 : 1);

        this.pos = start > end ? text.length : 0;

        this.from = Math.min(start, end);

        this.to = Math.max(start, end);

    }

    nextInner(skip, dir) {

        if (dir < 0 ? this.pos <= this.from : this.pos >= this.to) {

            this.value = "";

            this.done = true;

            return this;

        }

        skip += Math.max(0, dir < 0 ? this.pos - this.to : this.from - this.pos);

        let limit = dir < 0 ? this.pos - this.from : this.to - this.pos;

        if (skip > limit)

            skip = limit;

        limit -= skip;

        let { value } = this.cursor.next(skip);

        this.pos += (value.length + skip) * dir;

        this.value = value.length <= limit ? value : dir < 0 ? value.slice(value.length - limit) : value.slice(0, limit);

        this.done = !this.value;

        return this;

    }

    next(skip = 0) {

        if (skip < 0)

            skip = Math.max(skip, this.from - this.pos);

        else if (skip > 0)

            skip = Math.min(skip, this.to - this.pos);

        return this.nextInner(skip, this.cursor.dir);

    }

    get lineBreak() { return this.cursor.lineBreak && this.value != ""; }

}

class LineCursor {

    constructor(inner) {

        this.inner = inner;

        this.afterBreak = true;

        this.value = "";

        this.done = false;

    }

    next(skip = 0) {

        let { done, lineBreak, value } = this.inner.next(skip);

        if (done && this.afterBreak) {

            this.value = "";

            this.afterBreak = false;

        }

        else if (done) {

            this.done = true;

            this.value = "";

        }

        else if (lineBreak) {

            if (this.afterBreak) {

                this.value = "";

            }

            else {

                this.afterBreak = true;

                this.next();

            }

        }

        else {

            this.value = value;

            this.afterBreak = false;

        }

        return this;

    }

    get lineBreak() { return false; }

}

if (typeof Symbol != "undefined") {

    Text.prototype[Symbol.iterator] = function () { return this.iter(); };

    RawTextCursor.prototype[Symbol.iterator] = PartialTextCursor.prototype[Symbol.iterator] =

        LineCursor.prototype[Symbol.iterator] = function () { return this; };

}

/**

This type describes a line in the document. It is created

on-demand when lines are [queried](https://codemirror.net/6/docs/ref/#state.Text.lineAt).

*/

class Line {

    /**

    @internal

    */

    constructor(

    /**

    The position of the start of the line.

    */

    from,

    /**

    The position at the end of the line (_before_ the line break,

    or at the end of document for the last line).

    */

    to,

    /**

    This line's line number (1-based).

    */

    number,

    /**

    The line's content.

    */

    text) {

        this.from = from;

        this.to = to;

        this.number = number;

        this.text = text;

    }

    /**

    The length of the line (not including any line break after it).

    */

    get length() { return this.to - this.from; }

}

function clip(text, from, to) {

    from = Math.max(0, Math.min(text.length, from));

    return [from, Math.max(from, Math.min(text.length, to))];

}

// Compressed representation of the Grapheme_Cluster_Break=Extend

// information from

// http://www.unicode.org/Public/13.0.0/ucd/auxiliary/GraphemeBreakProperty.txt.

// Each pair of elements represents a range, as an offet from the

// previous range and a length. Numbers are in base-36, with the empty

// string being a shorthand for 1.

let extend = /*@__PURE__*/"lc,34,7n,7,7b,19,,,,2,,2,,,20,b,1c,l,g,,2t,7,2,6,2,2,,4,z,,u,r,2j,b,1m,9,9,,o,4,,9,,3,,5,17,3,3b,f,,w,1j,,,,4,8,4,,3,7,a,2,t,,1m,,,,2,4,8,,9,,a,2,q,,2,2,1l,,4,2,4,2,2,3,3,,u,2,3,,b,2,1l,,4,5,,2,4,,k,2,m,6,,,1m,,,2,,4,8,,7,3,a,2,u,,1n,,,,c,,9,,14,,3,,1l,3,5,3,,4,7,2,b,2,t,,1m,,2,,2,,3,,5,2,7,2,b,2,s,2,1l,2,,,2,4,8,,9,,a,2,t,,20,,4,,2,3,,,8,,29,,2,7,c,8,2q,,2,9,b,6,22,2,r,,,,,,1j,e,,5,,2,5,b,,10,9,,2u,4,,6,,2,2,2,p,2,4,3,g,4,d,,2,2,6,,f,,jj,3,qa,3,t,3,t,2,u,2,1s,2,,7,8,,2,b,9,,19,3,3b,2,y,,3a,3,4,2,9,,6,3,63,2,2,,1m,,,7,,,,,2,8,6,a,2,,1c,h,1r,4,1c,7,,,5,,14,9,c,2,w,4,2,2,,3,1k,,,2,3,,,3,1m,8,2,2,48,3,,d,,7,4,,6,,3,2,5i,1m,,5,ek,,5f,x,2da,3,3x,,2o,w,fe,6,2x,2,n9w,4,,a,w,2,28,2,7k,,3,,4,,p,2,5,,47,2,q,i,d,,12,8,p,b,1a,3,1c,,2,4,2,2,13,,1v,6,2,2,2,2,c,,8,,1b,,1f,,,3,2,2,5,2,,,16,2,8,,6m,,2,,4,,fn4,,kh,g,g,g,a6,2,gt,,6a,,45,5,1ae,3,,2,5,4,14,3,4,,4l,2,fx,4,ar,2,49,b,4w,,1i,f,1k,3,1d,4,2,2,1x,3,10,5,,8,1q,,c,2,1g,9,a,4,2,,2n,3,2,,,2,6,,4g,,3,8,l,2,1l,2,,,,,m,,e,7,3,5,5f,8,2,3,,,n,,29,,2,6,,,2,,,2,,2,6j,,2,4,6,2,,2,r,2,2d,8,2,,,2,2y,,,,2,6,,,2t,3,2,4,,5,77,9,,2,6t,,a,2,,,4,,40,4,2,2,4,,w,a,14,6,2,4,8,,9,6,2,3,1a,d,,2,ba,7,,6,,,2a,m,2,7,,2,,2,3e,6,3,,,2,,7,,,20,2,3,,,,9n,2,f0b,5,1n,7,t4,,1r,4,29,,f5k,2,43q,,,3,4,5,8,8,2,7,u,4,44,3,1iz,1j,4,1e,8,,e,,m,5,,f,11s,7,,h,2,7,,2,,5,79,7,c5,4,15s,7,31,7,240,5,gx7k,2o,3k,6o".split(",").map(s => s ? parseInt(s, 36) : 1);

// Convert offsets into absolute values

for (let i = 1; i < extend.length; i++)

    extend[i] += extend[i - 1];

function isExtendingChar(code) {

    for (let i = 1; i < extend.length; i += 2)

        if (extend[i] > code)

            return extend[i - 1] <= code;

    return false;

}

function isRegionalIndicator(code) {

    return code >= 0x1F1E6 && code <= 0x1F1FF;

}

const ZWJ = 0x200d;

/**

Returns a next grapheme cluster break _after_ (not equal to)

`pos`, if `forward` is true, or before otherwise. Returns `pos`

itself if no further cluster break is available in the string.

Moves across surrogate pairs, extending characters (when

`includeExtending` is true), characters joined with zero-width

joiners, and flag emoji.

*/

function findClusterBreak(str, pos, forward = true, includeExtending = true) {

    return (forward ? nextClusterBreak : prevClusterBreak)(str, pos, includeExtending);

}

function nextClusterBreak(str, pos, includeExtending) {

    if (pos == str.length)

        return pos;

    // If pos is in the middle of a surrogate pair, move to its start

    if (pos && surrogateLow(str.charCodeAt(pos)) && surrogateHigh(str.charCodeAt(pos - 1)))

        pos--;

    let prev = codePointAt(str, pos);

    pos += codePointSize(prev);

    while (pos < str.length) {

        let next = codePointAt(str, pos);

        if (prev == ZWJ || next == ZWJ || includeExtending && isExtendingChar(next)) {

            pos += codePointSize(next);

            prev = next;

        }

        else if (isRegionalIndicator(next)) {

            let countBefore = 0, i = pos - 2;

            while (i >= 0 && isRegionalIndicator(codePointAt(str, i))) {

                countBefore++;

                i -= 2;

            }

            if (countBefore % 2 == 0)

                break;

            else

                pos += 2;

        }

        else {

            break;

        }

    }

    return pos;

}

function prevClusterBreak(str, pos, includeExtending) {

    while (pos > 0) {

        let found = nextClusterBreak(str, pos - 2, includeExtending);

        if (found < pos)

            return found;

        pos--;

    }

    return 0;

}

function surrogateLow(ch) { return ch >= 0xDC00 && ch < 0xE000; }

function surrogateHigh(ch) { return ch >= 0xD800 && ch < 0xDC00; }

/**

Find the code point at the given position in a string (like the

[`codePointAt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/codePointAt)

string method).

*/

function codePointAt(str, pos) {

    let code0 = str.charCodeAt(pos);

    if (!surrogateHigh(code0) || pos + 1 == str.length)

        return code0;

    let code1 = str.charCodeAt(pos + 1);

    if (!surrogateLow(code1))

        return code0;

    return ((code0 - 0xd800) << 10) + (code1 - 0xdc00) + 0x10000;

}

/**

Given a Unicode codepoint, return the JavaScript string that

respresents it (like

[`String.fromCodePoint`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/fromCodePoint)).

*/

function fromCodePoint(code) {

    if (code <= 0xffff)

        return String.fromCharCode(code);

    code -= 0x10000;

    return String.fromCharCode((code >> 10) + 0xd800, (code & 1023) + 0xdc00);

}

/**

The amount of positions a character takes up a JavaScript string.

*/

function codePointSize(code) { return code < 0x10000 ? 1 : 2; }

const DefaultSplit = /\r\n?|\n/;

/**

Distinguishes different ways in which positions can be mapped.

*/

var MapMode = /*@__PURE__*/(function (MapMode) {

    /**

    Map a position to a valid new position, even when its context

    was deleted.

    */

    MapMode[MapMode["Simple"] = 0] = "Simple";

    /**

    Return null if deletion happens across the position.

    */

    MapMode[MapMode["TrackDel"] = 1] = "TrackDel";

    /**

    Return null if the character _before_ the position is deleted.

    */

    MapMode[MapMode["TrackBefore"] = 2] = "TrackBefore";

    /**

    Return null if the character _after_ the position is deleted.

    */

    MapMode[MapMode["TrackAfter"] = 3] = "TrackAfter";

return MapMode})(MapMode || (MapMode = {}));

/**

A change description is a variant of [change set](https://codemirror.net/6/docs/ref/#state.ChangeSet)

that doesn't store the inserted text. As such, it can't be

applied, but is cheaper to store and manipulate.

*/

class ChangeDesc {

    // Sections are encoded as pairs of integers. The first is the

    // length in the current document, and the second is -1 for

    // unaffected sections, and the length of the replacement content

    // otherwise. So an insertion would be (0, n>0), a deletion (n>0,

    // 0), and a replacement two positive numbers.

    /**

    @internal

    */

    constructor(

    /**

    @internal

    */

    sections) {

        this.sections = sections;

    }

    /**

    The length of the document before the change.

    */

    get length() {

        let result = 0;

        for (let i = 0; i < this.sections.length; i += 2)

            result += this.sections[i];

        return result;

    }

    /**

    The length of the document after the change.

    */

    get newLength() {

        let result = 0;

        for (let i = 0; i < this.sections.length; i += 2) {

            let ins = this.sections[i + 1];

            result += ins < 0 ? this.sections[i] : ins;

        }

        return result;

    }

    /**

    False when there are actual changes in this set.

    */

    get empty() { return this.sections.length == 0 || this.sections.length == 2 && this.sections[1] < 0; }

    /**

    Iterate over the unchanged parts left by these changes. `posA`

    provides the position of the range in the old document, `posB`

    the new position in the changed document.

    */

    iterGaps(f) {

        for (let i = 0, posA = 0, posB = 0; i < this.sections.length;) {

            let len = this.sections[i++], ins = this.sections[i++];

            if (ins < 0) {

                f(posA, posB, len);

                posB += len;

            }

            else {

                posB += ins;

            }

            posA += len;

        }

    }

    /**

    Iterate over the ranges changed by these changes. (See

    [`ChangeSet.iterChanges`](https://codemirror.net/6/docs/ref/#state.ChangeSet.iterChanges) for a

    variant that also provides you with the inserted text.)

    `fromA`/`toA` provides the extent of the change in the starting

    document, `fromB`/`toB` the extent of the replacement in the

    changed document.

    When `individual` is true, adjacent changes (which are kept

    separate for [position mapping](https://codemirror.net/6/docs/ref/#state.ChangeDesc.mapPos)) are

    reported separately.

    */

    iterChangedRanges(f, individual = false) {

        iterChanges(this, f, individual);

    }

    /**

    Get a description of the inverted form of these changes.

    */

    get invertedDesc() {

        let sections = [];

        for (let i = 0; i < this.sections.length;) {

            let len = this.sections[i++], ins = this.sections[i++];

            if (ins < 0)

                sections.push(len, ins);

            else

                sections.push(ins, len);

        }

        return new ChangeDesc(sections);

    }

    /**

    Compute the combined effect of applying another set of changes

    after this one. The length of the document after this set should

    match the length before `other`.

    */

    composeDesc(other) { return this.empty ? other : other.empty ? this : composeSets(this, other); }

    /**

    Map this description, which should start with the same document

    as `other`, over another set of changes, so that it can be

    applied after it. When `before` is true, map as if the changes

    in `other` happened before the ones in `this`.

    */

    mapDesc(other, before = false) { return other.empty ? this : mapSet(this, other, before); }

    mapPos(pos, assoc = -1, mode = MapMode.Simple) {

        let posA = 0, posB = 0;

        for (let i = 0; i < this.sections.length;) {

            let len = this.sections[i++], ins = this.sections[i++], endA = posA + len;

            if (ins < 0) {

                if (endA > pos)

                    return posB + (pos - posA);

                posB += len;

            }

            else {

                if (mode != MapMode.Simple && endA >= pos &&

                    (mode == MapMode.TrackDel && posA < pos && endA > pos ||

                        mode == MapMode.TrackBefore && posA < pos ||

                        mode == MapMode.TrackAfter && endA > pos))

                    return null;

                if (endA > pos || endA == pos && assoc < 0 && !len)

                    return pos == posA || assoc < 0 ? posB : posB + ins;

                posB += ins;

            }

            posA = endA;

        }

        if (pos > posA)

            throw new RangeError(`Position ${pos} is out of range for changeset of length ${posA}`);

        return posB;

    }

    /**

    Check whether these changes touch a given range. When one of the

    changes entirely covers the range, the string `"cover"` is

    returned.

    */

    touchesRange(from, to = from) {

        for (let i = 0, pos = 0; i < this.sections.length && pos <= to;) {

            let len = this.sections[i++], ins = this.sections[i++], end = pos + len;

            if (ins >= 0 && pos <= to && end >= from)

                return pos < from && end > to ? "cover" : true;

            pos = end;

        }

        return false;

    }

    /**

    @internal

    */

    toString() {

        let result = "";

        for (let i = 0; i < this.sections.length;) {

            let len = this.sections[i++], ins = this.sections[i++];

            result += (result ? " " : "") + len + (ins >= 0 ? ":" + ins : "");

        }

        return result;

    }

    /**

    Serialize this change desc to a JSON-representable value.

    */

    toJSON() { return this.sections; }

    /**

    Create a change desc from its JSON representation (as produced

    by [`toJSON`](https://codemirror.net/6/docs/ref/#state.ChangeDesc.toJSON).

    */

    static fromJSON(json) {

        if (!Array.isArray(json) || json.length % 2 || json.some(a => typeof a != "number"))

            throw new RangeError("Invalid JSON representation of ChangeDesc");

        return new ChangeDesc(json);

    }

    /**

    @internal

    */

    static create(sections) { return new ChangeDesc(sections); }

}

/**

A change set represents a group of modifications to a document. It

stores the document length, and can only be applied to documents

with exactly that length.

*/

class ChangeSet extends ChangeDesc {

    constructor(sections,

    /**

    @internal

    */

    inserted) {

        super(sections);

        this.inserted = inserted;

    }

    /**

    Apply the changes to a document, returning the modified

    document.

    */

    apply(doc) {

        if (this.length != doc.length)

            throw new RangeError("Applying change set to a document with the wrong length");

        iterChanges(this, (fromA, toA, fromB, _toB, text) => doc = doc.replace(fromB, fromB + (toA - fromA), text), false);

        return doc;

    }

    mapDesc(other, before = false) { return mapSet(this, other, before, true); }

    /**

    Given the document as it existed _before_ the changes, return a

    change set that represents the inverse of this set, which could

    be used to go from the document created by the changes back to

    the document as it existed before the changes.

    */

    invert(doc) {

        let sections = this.sections.slice(), inserted = [];

        for (let i = 0, pos = 0; i < sections.length; i += 2) {

            let len = sections[i], ins = sections[i + 1];

            if (ins >= 0) {

                sections[i] = ins;

                sections[i + 1] = len;

                let index = i >> 1;

                while (inserted.length < index)

                    inserted.push(Text.empty);

                inserted.push(len ? doc.slice(pos, pos + len) : Text.empty);

            }

            pos += len;

        }

        return new ChangeSet(sections, inserted);

    }

    /**

    Combine two subsequent change sets into a single set. `other`

    must start in the document produced by `this`. If `this` goes

    `docA` → `docB` and `other` represents `docB` → `docC`, the

    returned value will represent the change `docA` → `docC`.

    */

    compose(other) { return this.empty ? other : other.empty ? this : composeSets(this, other, true); }

    /**

    Given another change set starting in the same document, maps this

    change set over the other, producing a new change set that can be

    applied to the document produced by applying `other`. When

    `before` is `true`, order changes as if `this` comes before

    `other`, otherwise (the default) treat `other` as coming first.

    Given two changes `A` and `B`, `A.compose(B.map(A))` and

    `B.compose(A.map(B, true))` will produce the same document. This

    provides a basic form of [operational

    transformation](https://en.wikipedia.org/wiki/Operational_transformation),

    and can be used for collaborative editing.

    */

    map(other, before = false) { return other.empty ? this : mapSet(this, other, before, true); }

    /**

    Iterate over the changed ranges in the document, calling `f` for

    each, with the range in the original document (`fromA`-`toA`)

    and the range that replaces it in the new document

    (`fromB`-`toB`).

    When `individual` is true, adjacent changes are reported

    separately.

    */

    iterChanges(f, individual = false) {

        iterChanges(this, f, individual);

    }

    /**

    Get a [change description](https://codemirror.net/6/docs/ref/#state.ChangeDesc) for this change

    set.

    */

    get desc() { return ChangeDesc.create(this.sections); }

    /**

    @internal

    */

    filter(ranges) {

        let resultSections = [], resultInserted = [], filteredSections = [];

        let iter = new SectionIter(this);

        done: for (let i = 0, pos = 0;;) {

            let next = i == ranges.length ? 1e9 : ranges[i++];

            while (pos < next || pos == next && iter.len == 0) {

                if (iter.done)

                    break done;

                let len = Math.min(iter.len, next - pos);

                addSection(filteredSections, len, -1);

                let ins = iter.ins == -1 ? -1 : iter.off == 0 ? iter.ins : 0;

                addSection(resultSections, len, ins);

                if (ins > 0)

                    addInsert(resultInserted, resultSections, iter.text);

                iter.forward(len);

                pos += len;

            }

            let end = ranges[i++];

            while (pos < end) {

                if (iter.done)

                    break done;

                let len = Math.min(iter.len, end - pos);

                addSection(resultSections, len, -1);

                addSection(filteredSections, len, iter.ins == -1 ? -1 : iter.off == 0 ? iter.ins : 0);

                iter.forward(len);

                pos += len;

            }

        }

        return { changes: new ChangeSet(resultSections, resultInserted),

            filtered: ChangeDesc.create(filteredSections) };

    }

    /**

    Serialize this change set to a JSON-representable value.

    */

    toJSON() {

        let parts = [];

        for (let i = 0; i < this.sections.length; i += 2) {

            let len = this.sections[i], ins = this.sections[i + 1];

            if (ins < 0)