'use strict';

/**
The default maximum length of a `TreeBuffer` node.
*/
const DefaultBufferLength = 1024;
let nextPropID = 0;
class Range {
    constructor(from, to) {
        this.from = from;
        this.to = to;
    }
}
/**
Each [node type](#common.NodeType) or [individual tree](#common.Tree)
can have metadata associated with it in props. Instances of this
class represent prop names.
*/
class NodeProp {
    /**
    Create a new node prop type.
    */
    constructor(config = {}) {
        this.id = nextPropID++;
        this.perNode = !!config.perNode;
        this.deserialize = config.deserialize || (() => {
            throw new Error("This node type doesn't define a deserialize function");
        });
    }
    /**
    This is meant to be used with
    [`NodeSet.extend`](#common.NodeSet.extend) or
    [`LRParser.configure`](#lr.ParserConfig.props) to compute
    prop values for each node type in the set. Takes a [match
    object](#common.NodeType^match) or function that returns undefined
    if the node type doesn't get this prop, and the prop's value if
    it does.
    */
    add(match) {
        if (this.perNode)
            throw new RangeError("Can't add per-node props to node types");
        if (typeof match != "function")
            match = NodeType.match(match);
        return (type) => {
            let result = match(type);
            return result === undefined ? null : [this, result];
        };
    }
}
/**
Prop that is used to describe matching delimiters. For opening
delimiters, this holds an array of node names (written as a
space-separated string when declaring this prop in a grammar)
for the node types of closing delimiters that match it.
*/
NodeProp.closedBy = new NodeProp({ deserialize: str => str.split(" ") });
/**
The inverse of [`closedBy`](#common.NodeProp^closedBy). This is
attached to closing delimiters, holding an array of node names
of types of matching opening delimiters.
*/
NodeProp.openedBy = new NodeProp({ deserialize: str => str.split(" ") });
/**
Used to assign node types to groups (for example, all node
types that represent an expression could be tagged with an
`"Expression"` group).
*/
NodeProp.group = new NodeProp({ deserialize: str => str.split(" ") });
/**
Attached to nodes to indicate these should be
[displayed](https://codemirror.net/docs/ref/#language.syntaxTree)
in a bidirectional text isolate, so that direction-neutral
characters on their sides don't incorrectly get associated with
surrounding text. You'll generally want to set this for nodes
that contain arbitrary text, like strings and comments, and for
nodes that appear _inside_ arbitrary text, like HTML tags. When
not given a value, in a grammar declaration, defaults to
`"auto"`.
*/
NodeProp.isolate = new NodeProp({ deserialize: value => {
        if (value && value != "rtl" && value != "ltr" && value != "auto")
            throw new RangeError("Invalid value for isolate: " + value);
        return value || "auto";
    } });
/**
The hash of the [context](#lr.ContextTracker.constructor)
that the node was parsed in, if any. Used to limit reuse of
contextual nodes.
*/
NodeProp.contextHash = new NodeProp({ perNode: true });
/**
The distance beyond the end of the node that the tokenizer
looked ahead for any of the tokens inside the node. (The LR
parser only stores this when it is larger than 25, for
efficiency reasons.)
*/
NodeProp.lookAhead = new NodeProp({ perNode: true });
/**
This per-node prop is used to replace a given node, or part of a
node, with another tree. This is useful to include trees from
different languages in mixed-language parsers.
*/
NodeProp.mounted = new NodeProp({ perNode: true });
/**
A mounted tree, which can be [stored](#common.NodeProp^mounted) on
a tree node to indicate that parts of its content are
represented by another tree.
*/
class MountedTree {
    constructor(
    /**
    The inner tree.
    */
    tree, 
    /**
    If this is null, this tree replaces the entire node (it will
    be included in the regular iteration instead of its host
    node). If not, only the given ranges are considered to be
    covered by this tree. This is used for trees that are mixed in
    a way that isn't strictly hierarchical. Such mounted trees are
    only entered by [`resolveInner`](#common.Tree.resolveInner)
    and [`enter`](#common.SyntaxNode.enter).
    */
    overlay, 
    /**
    The parser used to create this subtree.
    */
    parser) {
        this.tree = tree;
        this.overlay = overlay;
        this.parser = parser;
    }
    /**
    @internal
    */
    static get(tree) {
        return tree && tree.props && tree.props[NodeProp.mounted.id];
    }
}
const noProps = Object.create(null);
/**
Each node in a syntax tree has a node type associated with it.
*/
class NodeType {
    /**
    @internal
    */
    constructor(
    /**
    The name of the node type. Not necessarily unique, but if the
    grammar was written properly, different node types with the
    same name within a node set should play the same semantic
    role.
    */
    name, 
    /**
    @internal
    */
    props, 
    /**
    The id of this node in its set. Corresponds to the term ids
    used in the parser.
    */
    id, 
    /**
    @internal
    */
    flags = 0) {
        this.name = name;
        this.props = props;
        this.id = id;
        this.flags = flags;
    }
    /**
    Define a node type.
    */
    static define(spec) {
        let props = spec.props && spec.props.length ? Object.create(null) : noProps;
        let flags = (spec.top ? 1 /* NodeFlag.Top */ : 0) | (spec.skipped ? 2 /* NodeFlag.Skipped */ : 0) |
            (spec.error ? 4 /* NodeFlag.Error */ : 0) | (spec.name == null ? 8 /* NodeFlag.Anonymous */ : 0);
        let type = new NodeType(spec.name || "", props, spec.id, flags);
        if (spec.props)
            for (let src of spec.props) {
                if (!Array.isArray(src))
                    src = src(type);
                if (src) {
                    if (src[0].perNode)
                        throw new RangeError("Can't store a per-node prop on a node type");
                    props[src[0].id] = src[1];
                }
            }
        return type;
    }
    /**
    Retrieves a node prop for this type. Will return `undefined` if
    the prop isn't present on this node.
    */
    prop(prop) { return this.props[prop.id]; }
    /**
    True when this is the top node of a grammar.
    */
    get isTop() { return (this.flags & 1 /* NodeFlag.Top */) > 0; }
    /**
    True when this node is produced by a skip rule.
    */
    get isSkipped() { return (this.flags & 2 /* NodeFlag.Skipped */) > 0; }
    /**
    Indicates whether this is an error node.
    */
    get isError() { return (this.flags & 4 /* NodeFlag.Error */) > 0; }
    /**
    When true, this node type doesn't correspond to a user-declared
    named node, for example because it is used to cache repetition.
    */
    get isAnonymous() { return (this.flags & 8 /* NodeFlag.Anonymous */) > 0; }
    /**
    Returns true when this node's name or one of its
    [groups](#common.NodeProp^group) matches the given string.
    */
    is(name) {
        if (typeof name == 'string') {
            if (this.name == name)
                return true;
            let group = this.prop(NodeProp.group);
            return group ? group.indexOf(name) > -1 : false;
        }
        return this.id == name;
    }
    /**
    Create a function from node types to arbitrary values by
    specifying an object whose property names are node or
    [group](#common.NodeProp^group) names. Often useful with
    [`NodeProp.add`](#common.NodeProp.add). You can put multiple
    names, separated by spaces, in a single property name to map
    multiple node names to a single value.
    */
    static match(map) {
        let direct = Object.create(null);
        for (let prop in map)
            for (let name of prop.split(" "))
                direct[name] = map[prop];
        return (node) => {
            for (let groups = node.prop(NodeProp.group), i = -1; i < (groups ? groups.length : 0); i++) {
                let found = direct[i < 0 ? node.name : groups[i]];
                if (found)
                    return found;
            }
        };
    }
}
/**
An empty dummy node type to use when no actual type is available.
*/
NodeType.none = new NodeType("", Object.create(null), 0, 8 /* NodeFlag.Anonymous */);
/**
A node set holds a collection of node types. It is used to
compactly represent trees by storing their type ids, rather than a
full pointer to the type object, in a numeric array. Each parser
[has](#lr.LRParser.nodeSet) a node set, and [tree
buffers](#common.TreeBuffer) can only store collections of nodes
from the same set. A set can have a maximum of 2**16 (65536) node
types in it, so that the ids fit into 16-bit typed array slots.
*/
class NodeSet {
    /**
    Create a set with the given types. The `id` property of each
    type should correspond to its position within the array.
    */
    constructor(
    /**
    The node types in this set, by id.
    */
    types) {
        this.types = types;
        for (let i = 0; i < types.length; i++)
            if (types[i].id != i)
                throw new RangeError("Node type ids should correspond to array positions when creating a node set");
    }
    /**
    Create a copy of this set with some node properties added. The
    arguments to this method can be created with
    [`NodeProp.add`](#common.NodeProp.add).
    */
    extend(...props) {
        let newTypes = [];
        for (let type of this.types) {
            let newProps = null;
            for (let source of props) {
                let add = source(type);
                if (add) {
                    if (!newProps)
                        newProps = Object.assign({}, type.props);
                    newProps[add[0].id] = add[1];
                }
            }
            newTypes.push(newProps ? new NodeType(type.name, newProps, type.id, type.flags) : type);
        }
        return new NodeSet(newTypes);
    }
}
const CachedNode = new WeakMap(), CachedInnerNode = new WeakMap();
/**
Options that control iteration. Can be combined with the `|`
operator to enable multiple ones.
*/
exports.IterMode = void 0;
(function (IterMode) {
    /**
    When enabled, iteration will only visit [`Tree`](#common.Tree)
    objects, not nodes packed into
    [`TreeBuffer`](#common.TreeBuffer)s.
    */
    IterMode[IterMode["ExcludeBuffers"] = 1] = "ExcludeBuffers";
    /**
    Enable this to make iteration include anonymous nodes (such as
    the nodes that wrap repeated grammar constructs into a balanced
    tree).
    */
    IterMode[IterMode["IncludeAnonymous"] = 2] = "IncludeAnonymous";
    /**
    By default, regular [mounted](#common.NodeProp^mounted) nodes
    replace their base node in iteration. Enable this to ignore them
    instead.
    */
    IterMode[IterMode["IgnoreMounts"] = 4] = "IgnoreMounts";
    /**
    This option only applies in
    [`enter`](#common.SyntaxNode.enter)-style methods. It tells the
    library to not enter mounted overlays if one covers the given
    position.
    */
    IterMode[IterMode["IgnoreOverlays"] = 8] = "IgnoreOverlays";
})(exports.IterMode || (exports.IterMode = {}));
/**
A piece of syntax tree. There are two ways to approach these
trees: the way they are actually stored in memory, and the
convenient way.

Syntax trees are stored as a tree of `Tree` and `TreeBuffer`
objects. By packing detail information into `TreeBuffer` leaf
nodes, the representation is made a lot more memory-efficient.

However, when you want to actually work with tree nodes, this
representation is very awkward, so most client code will want to
use the [`TreeCursor`](#common.TreeCursor) or
[`SyntaxNode`](#common.SyntaxNode) interface instead, which provides
a view on some part of this data structure, and can be used to
move around to adjacent nodes.
*/
class Tree {
    /**
    Construct a new tree. See also [`Tree.build`](#common.Tree^build).
    */
    constructor(
    /**
    The type of the top node.
    */
    type, 
    /**
    This node's child nodes.
    */
    children, 
    /**
    The positions (offsets relative to the start of this tree) of
    the children.
    */
    positions, 
    /**
    The total length of this tree
    */
    length, 
    /**
    Per-node [node props](#common.NodeProp) to associate with this node.
    */
    props) {
        this.type = type;
        this.children = children;
        this.positions = positions;
        this.length = length;
        /**
        @internal
        */
        this.props = null;
        if (props && props.length) {
            this.props = Object.create(null);
            for (let [prop, value] of props)
                this.props[typeof prop == "number" ? prop : prop.id] = value;
        }
    }
    /**
    @internal
    */
    toString() {
        let mounted = MountedTree.get(this);
        if (mounted && !mounted.overlay)
            return mounted.tree.toString();
        let children = "";
        for (let ch of this.children) {
            let str = ch.toString();
            if (str) {
                if (children)
                    children += ",";
                children += str;
            }
        }
        return !this.type.name ? children :
            (/\W/.test(this.type.name) && !this.type.isError ? JSON.stringify(this.type.name) : this.type.name) +
                (children.length ? "(" + children + ")" : "");
    }
    /**
    Get a [tree cursor](#common.TreeCursor) positioned at the top of
    the tree. Mode can be used to [control](#common.IterMode) which
    nodes the cursor visits.
    */
    cursor(mode = 0) {
        return new TreeCursor(this.topNode, mode);
    }
    /**
    Get a [tree cursor](#common.TreeCursor) pointing into this tree
    at the given position and side (see
    [`moveTo`](#common.TreeCursor.moveTo).
    */
    cursorAt(pos, side = 0, mode = 0) {
        let scope = CachedNode.get(this) || this.topNode;
        let cursor = new TreeCursor(scope);
        cursor.moveTo(pos, side);
        CachedNode.set(this, cursor._tree);
        return cursor;
    }
    /**
    Get a [syntax node](#common.SyntaxNode) object for the top of the
    tree.
    */
    get topNode() {
        return new TreeNode(this, 0, 0, null);
    }
    /**
    Get the [syntax node](#common.SyntaxNode) at the given position.
    If `side` is -1, this will move into nodes that end at the
    position. If 1, it'll move into nodes that start at the
    position. With 0, it'll only enter nodes that cover the position
    from both sides.
    
    Note that this will not enter
    [overlays](#common.MountedTree.overlay), and you often want
    [`resolveInner`](#common.Tree.resolveInner) instead.
    */
    resolve(pos, side = 0) {
        let node = resolveNode(CachedNode.get(this) || this.topNode, pos, side, false);
        CachedNode.set(this, node);
        return node;
    }
    /**
    Like [`resolve`](#common.Tree.resolve), but will enter
    [overlaid](#common.MountedTree.overlay) nodes, producing a syntax node
    pointing into the innermost overlaid tree at the given position
    (with parent links going through all parent structure, including
    the host trees).
    */
    resolveInner(pos, side = 0) {
        let node = resolveNode(CachedInnerNode.get(this) || this.topNode, pos, side, true);
        CachedInnerNode.set(this, node);
        return node;
    }
    /**
    In some situations, it can be useful to iterate through all
    nodes around a position, including those in overlays that don't
    directly cover the position. This method gives you an iterator
    that will produce all nodes, from small to big, around the given
    position.
    */
    resolveStack(pos, side = 0) {
        return stackIterator(this, pos, side);
    }
    /**
    Iterate over the tree and its children, calling `enter` for any
    node that touches the `from`/`to` region (if given) before
    running over such a node's children, and `leave` (if given) when
    leaving the node. When `enter` returns `false`, that node will
    not have its children iterated over (or `leave` called).
    */
    iterate(spec) {
        let { enter, leave, from = 0, to = this.length } = spec;
        let mode = spec.mode || 0, anon = (mode & exports.IterMode.IncludeAnonymous) > 0;
        for (let c = this.cursor(mode | exports.IterMode.IncludeAnonymous);;) {
            let entered = false;
            if (c.from <= to && c.to >= from && (!anon && c.type.isAnonymous || enter(c) !== false)) {
                if (c.firstChild())
                    continue;
                entered = true;
            }
            for (;;) {
                if (entered && leave && (anon || !c.type.isAnonymous))
                    leave(c);
                if (c.nextSibling())
                    break;
                if (!c.parent())
                    return;
                entered = true;
            }
        }
    }
    /**
    Get the value of the given [node prop](#common.NodeProp) for this
    node. Works with both per-node and per-type props.
    */
    prop(prop) {
        return !prop.perNode ? this.type.prop(prop) : this.props ? this.props[prop.id] : undefined;
    }
    /**
    Returns the node's [per-node props](#common.NodeProp.perNode) in a
    format that can be passed to the [`Tree`](#common.Tree)
    constructor.
    */
    get propValues() {
        let result = [];
        if (this.props)
            for (let id in this.props)
                result.push([+id, this.props[id]]);
        return result;
    }
    /**
    Balance the direct children of this tree, producing a copy of
    which may have children grouped into subtrees with type
    [`NodeType.none`](#common.NodeType^none).
    */
    balance(config = {}) {
        return this.children.length <= 8 /* Balance.BranchFactor */ ? this :
            balanceRange(NodeType.none, this.children, this.positions, 0, this.children.length, 0, this.length, (children, positions, length) => new Tree(this.type, children, positions, length, this.propValues), config.makeTree || ((children, positions, length) => new Tree(NodeType.none, children, positions, length)));
    }
    /**
    Build a tree from a postfix-ordered buffer of node information,
    or a cursor over such a buffer.
    */
    static build(data) { return buildTree(data); }
}
/**
The empty tree
*/
Tree.empty = new Tree(NodeType.none, [], [], 0);
class FlatBufferCursor {
    constructor(buffer, index) {
        this.buffer = buffer;
        this.index = index;
    }
    get id() { return this.buffer[this.index - 4]; }
    get start() { return this.buffer[this.index - 3]; }
    get end() { return this.buffer[this.index - 2]; }
    get size() { return this.buffer[this.index - 1]; }
    get pos() { return this.index; }
    next() { this.index -= 4; }
    fork() { return new FlatBufferCursor(this.buffer, this.index); }
}
/**
Tree buffers contain (type, start, end, endIndex) quads for each
node. In such a buffer, nodes are stored in prefix order (parents
before children, with the endIndex of the parent indicating which
children belong to it).
*/
class TreeBuffer {
    /**
    Create a tree buffer.
    */
    constructor(
    /**
    The buffer's content.
    */
    buffer, 
    /**
    The total length of the group of nodes in the buffer.
    */
    length, 
    /**
    The node set used in this buffer.
    */
    set) {
        this.buffer = buffer;
        this.length = length;
        this.set = set;
    }
    /**
    @internal
    */
    get type() { return NodeType.none; }
    /**
    @internal
    */
    toString() {
        let result = [];
        for (let index = 0; index < this.buffer.length;) {
            result.push(this.childString(index));
            index = this.buffer[index + 3];
        }
        return result.join(",");
    }
    /**
    @internal
    */
    childString(index) {
        let id = this.buffer[index], endIndex = this.buffer[index + 3];
        let type = this.set.types[id], result = type.name;
        if (/\W/.test(result) && !type.isError)
            result = JSON.stringify(result);
        index += 4;
        if (endIndex == index)
            return result;
        let children = [];
        while (index < endIndex) {
            children.push(this.childString(index));
            index = this.buffer[index + 3];
        }
        return result + "(" + children.join(",") + ")";
    }
    /**
    @internal
    */
    findChild(startIndex, endIndex, dir, pos, side) {
        let { buffer } = this, pick = -1;
        for (let i = startIndex; i != endIndex; i = buffer[i + 3]) {
            if (checkSide(side, pos, buffer[i + 1], buffer[i + 2])) {
                pick = i;
                if (dir > 0)
                    break;
            }
        }
        return pick;
    }
    /**
    @internal
    */
    slice(startI, endI, from) {
        let b = this.buffer;
        let copy = new Uint16Array(endI - startI), len = 0;
        for (let i = startI, j = 0; i < endI;) {
            copy[j++] = b[i++];
            copy[j++] = b[i++] - from;
            let to = copy[j++] = b[i++] - from;
            copy[j++] = b[i++] - startI;
            len = Math.max(len, to);
        }
        return new TreeBuffer(copy, len, this.set);
    }
}
function checkSide(side, pos, from, to) {
    switch (side) {
        case -2 /* Side.Before */: return from < pos;
        case -1 /* Side.AtOrBefore */: return to >= pos && from < pos;
        case 0 /* Side.Around */: return from < pos && to > pos;
        case 1 /* Side.AtOrAfter */: return from <= pos && to > pos;
        case 2 /* Side.After */: return to > pos;
        case 4 /* Side.DontCare */: return true;
    }
}
function resolveNode(node, pos, side, overlays) {
    var _a;
    // Move up to a node that actually holds the position, if possible
    while (node.from == node.to ||
        (side < 1 ? node.from >= pos : node.from > pos) ||
        (side > -1 ? node.to <= pos : node.to < pos)) {
        let parent = !overlays && node instanceof TreeNode && node.index < 0 ? null : node.parent;
        if (!parent)
            return node;
        node = parent;
    }
    let mode = overlays ? 0 : exports.IterMode.IgnoreOverlays;
    // Must go up out of overlays when those do not overlap with pos
    if (overlays)
        for (let scan = node, parent = scan.parent; parent; scan = parent, parent = scan.parent) {
            if (scan instanceof TreeNode && scan.index < 0 && ((_a = parent.enter(pos, side, mode)) === null || _a === void 0 ? void 0 : _a.from) != scan.from)
                node = parent;
        }
    for (;;) {
        let inner = node.enter(pos, side, mode);
        if (!inner)
            return node;
        node = inner;
    }
}
class BaseNode {
    cursor(mode = 0) { return new TreeCursor(this, mode); }
    getChild(type, before = null, after = null) {
        let r = getChildren(this, type, before, after);
        return r.length ? r[0] : null;
    }
    getChildren(type, before = null, after = null) {
        return getChildren(this, type, before, after);
    }
    resolve(pos, side = 0) {
        return resolveNode(this, pos, side, false);
    }
    resolveInner(pos, side = 0) {
        return resolveNode(this, pos, side, true);
    }
    matchContext(context) {
        return matchNodeContext(this, context);
    }
    enterUnfinishedNodesBefore(pos) {
        let scan = this.childBefore(pos), node = this;
        while (scan) {
            let last = scan.lastChild;
            if (!last || last.to != scan.to)
                break;
            if (last.type.isError && last.from == last.to) {
                node = scan;
                scan = last.prevSibling;
            }
            else {
                scan = last;
            }
        }
        return node;
    }
    get node() { return this; }
    get next() { return this.parent; }
}
class TreeNode extends BaseNode {
    constructor(_tree, from, 
    // Index in parent node, set to -1 if the node is not a direct child of _parent.node (overlay)
    index, _parent) {
        super();
        this._tree = _tree;
        this.from = from;
        this.index = index;
        this._parent = _parent;
    }
    get type() { return this._tree.type; }
    get name() { return this._tree.type.name; }
    get to() { return this.from + this._tree.length; }
    nextChild(i, dir, pos, side, mode = 0) {
        for (let parent = this;;) {
            for (let { children, positions } = parent._tree, e = dir > 0 ? children.length : -1; i != e; i += dir) {
                let next = children[i], start = positions[i] + parent.from;
                if (!checkSide(side, pos, start, start + next.length))
                    continue;
                if (next instanceof TreeBuffer) {
                    if (mode & exports.IterMode.ExcludeBuffers)
                        continue;
                    let index = next.findChild(0, next.buffer.length, dir, pos - start, side);
                    if (index > -1)
                        return new BufferNode(new BufferContext(parent, next, i, start), null, index);
                }
                else if ((mode & exports.IterMode.IncludeAnonymous) || (!next.type.isAnonymous || hasChild(next))) {
                    let mounted;
                    if (!(mode & exports.IterMode.IgnoreMounts) && (mounted = MountedTree.get(next)) && !mounted.overlay)
                        return new TreeNode(mounted.tree, start, i, parent);
                    let inner = new TreeNode(next, start, i, parent);
                    return (mode & exports.IterMode.IncludeAnonymous) || !inner.type.isAnonymous ? inner
                        : inner.nextChild(dir < 0 ? next.children.length - 1 : 0, dir, pos, side);
                }
            }
            if ((mode & exports.IterMode.IncludeAnonymous) || !parent.type.isAnonymous)
                return null;
            if (parent.index >= 0)
                i = parent.index + dir;
            else
                i = dir < 0 ? -1 : parent._parent._tree.children.length;
            parent = parent._parent;
            if (!parent)
                return null;
        }
    }
    get firstChild() { return this.nextChild(0, 1, 0, 4 /* Side.DontCare */); }
    get lastChild() { return this.nextChild(this._tree.children.length - 1, -1, 0, 4 /* Side.DontCare */); }
    childAfter(pos) { return this.nextChild(0, 1, pos, 2 /* Side.After */); }
    childBefore(pos) { return this.nextChild(this._tree.children.length - 1, -1, pos, -2 /* Side.Before */); }
    enter(pos, side, mode = 0) {
        let mounted;
        if (!(mode & exports.IterMode.IgnoreOverlays) && (mounted = MountedTree.get(this._tree)) && mounted.overlay) {
            let rPos = pos - this.from;
            for (let { from, to } of mounted.overlay) {
                if ((side > 0 ? from <= rPos : from < rPos) &&
                    (side < 0 ? to >= rPos : to > rPos))
                    return new TreeNode(mounted.tree, mounted.overlay[0].from + this.from, -1, this);
            }
        }
        return this.nextChild(0, 1, pos, side, mode);
    }
    nextSignificantParent() {
        let val = this;
        while (val.type.isAnonymous && val._parent)
            val = val._parent;
        return val;
    }
    get parent() {
        return this._parent ? this._parent.nextSignificantParent() : null;
    }
    get nextSibling() {
        return this._parent && this.index >= 0 ? this._parent.nextChild(this.index + 1, 1, 0, 4 /* Side.DontCare */) : null;
    }
    get prevSibling() {
        return this._parent && this.index >= 0 ? this._parent.nextChild(this.index - 1, -1, 0, 4 /* Side.DontCare */) : null;
    }
    get tree() { return this._tree; }
    toTree() { return this._tree; }
    /**
    @internal
    */
    toString() { return this._tree.toString(); }
}
function getChildren(node, type, before, after) {
    let cur = node.cursor(), result = [];
    if (!cur.firstChild())
        return result;
    if (before != null)
        for (let found = false; !found;) {
            found = cur.type.is(before);
            if (!cur.nextSibling())
                return result;
        }
    for (;;) {
        if (after != null && cur.type.is(after))
            return result;
        if (cur.type.is(type))
            result.push(cur.node);
        if (!cur.nextSibling())
            return after == null ? result : [];
    }
}
function matchNodeContext(node, context, i = context.length - 1) {
    for (let p = node.parent; i >= 0; p = p.parent) {
        if (!p)
            return false;
        if (!p.type.isAnonymous) {
            if (context[i] && context[i] != p.name)
                return false;
            i--;
        }
    }
    return true;
}
class BufferContext {
    constructor(parent, buffer, index, start) {
        this.parent = parent;
        this.buffer = buffer;
        this.index = index;
        this.start = start;
    }
}
class BufferNode extends BaseNode {
    get name() { return this.type.name; }
    get from() { return this.context.start + this.context.buffer.buffer[this.index + 1]; }
    get to() { return this.context.start + this.context.buffer.buffer[this.index + 2]; }
    constructor(context, _parent, index) {
        super();
        this.context = context;
        this._parent = _parent;
        this.index = index;
        this.type = context.buffer.set.types[context.buffer.buffer[index]];
    }
    child(dir, pos, side) {
        let { buffer } = this.context;
        let index = buffer.findChild(this.index + 4, buffer.buffer[this.index + 3], dir, pos - this.context.start, side);
        return index < 0 ? null : new BufferNode(this.context, this, index);
    }
    get firstChild() { return this.child(1, 0, 4 /* Side.DontCare */); }
    get lastChild() { return this.child(-1, 0, 4 /* Side.DontCare */); }
    childAfter(pos) { return this.child(1, pos, 2 /* Side.After */); }
    childBefore(pos) { return this.child(-1, pos, -2 /* Side.Before */); }
    enter(pos, side, mode = 0) {
        if (mode & exports.IterMode.ExcludeBuffers)
            return null;
        let { buffer } = this.context;
        let index = buffer.findChild(this.index + 4, buffer.buffer[this.index + 3], side > 0 ? 1 : -1, pos - this.context.start, side);
        return index < 0 ? null : new BufferNode(this.context, this, index);
    }
    get parent() {
        return this._parent || this.context.parent.nextSignificantParent();
    }
    externalSibling(dir) {
        return this._parent ? null : this.context.parent.nextChild(this.context.index + dir, dir, 0, 4 /* Side.DontCare */);
    }
    get nextSibling() {
        let { buffer } = this.context;
        let after = buffer.buffer[this.index + 3];
        if (after < (this._parent ? buffer.buffer[this._parent.index + 3] : buffer.buffer.length))
            return new BufferNode(this.context, this._parent, after);
        return this.externalSibling(1);
    }
    get prevSibling() {
        let { buffer } = this.context;
        let parentStart = this._parent ? this._parent.index + 4 : 0;
        if (this.index == parentStart)
            return this.externalSibling(-1);
        return new BufferNode(this.context, this._parent, buffer.findChild(parentStart, this.index, -1, 0, 4 /* Side.DontCare */));
    }
    get tree() { return null; }
    toTree() {
        let children = [], positions = [];
        let { buffer } = this.context;
        let startI = this.index + 4, endI = buffer.buffer[this.index + 3];
        if (endI > startI) {
            let from = buffer.buffer[this.index + 1];
            children.push(buffer.slice(startI, endI, from));
            positions.push(0);
        }
        return new Tree(this.type, children, positions, this.to - this.from);
    }
    /**
    @internal
    */
    toString() { return this.context.buffer.childString(this.index); }
}
function iterStack(heads) {
    if (!heads.length)
        return null;
    let pick = 0, picked = heads[0];
    for (let i = 1; i < heads.length; i++) {
        let node = heads[i];
        if (node.from > picked.from || node.to < picked.to) {
            picked = node;
            pick = i;
        }
    }
    let next = picked instanceof TreeNode && picked.index < 0 ? null : picked.parent;
    let newHeads = heads.slice();
    if (next)
        newHeads[pick] = next;
    else
        newHeads.splice(pick, 1);
    return new StackIterator(newHeads, picked);
}
class StackIterator {
    constructor(heads, node) {
        this.heads = heads;
        this.node = node;
    }
    get next() { return iterStack(this.heads); }
}
function stackIterator(tree, pos, side) {
    let inner = tree.resolveInner(pos, side), layers = null;
    for (let scan = inner instanceof TreeNode ? inner : inner.context.parent; scan; scan = scan.parent) {
        if (scan.index < 0) { // This is an overlay root
            let parent = scan.parent;
            (layers || (layers = [inner])).push(parent.resolve(pos, side));
            scan = parent;
        }
        else {
            let mount = MountedTree.get(scan.tree);
            // Relevant overlay branching off
            if (mount && mount.overlay && mount.overlay[0].from <= pos && mount.overlay[mount.overlay.length - 1].to >= pos) {
                let root = new TreeNode(mount.tree, mount.overlay[0].from + scan.from, -1, scan);
                (layers || (layers = [inner])).push(resolveNode(root, pos, side, false));
            }
        }
    }
    return layers ? iterStack(layers) : inner;
}
/**
A tree cursor object focuses on a given node in a syntax tree, and
allows you to move to adjacent nodes.
*/
class TreeCursor {
    /**
    Shorthand for `.type.name`.
    */
    get name() { return this.type.name; }
    /**
    @internal
    */
    constructor(node, 
    /**
    @internal
    */
    mode = 0) {
        this.mode = mode;
        /**
        @internal
        */
        this.buffer = null;
        this.stack = [];
        /**
        @internal
        */
        this.index = 0;
        this.bufferNode = null;
        if (node instanceof TreeNode) {
            this.yieldNode(node);
        }
        else {
            this._tree = node.context.parent;
            this.buffer = node.context;
            for (let n = node._parent; n; n = n._parent)
                this.stack.unshift(n.index);
            this.bufferNode = node;
            this.yieldBuf(node.index);
        }
    }
    yieldNode(node) {
        if (!node)
            return false;
        this._tree = node;
        this.type = node.type;
        this.from = node.from;
        this.to = node.to;
        return true;
    }
    yieldBuf(index, type) {
        this.index = index;
        let { start, buffer } = this.buffer;
        this.type = type || buffer.set.types[buffer.buffer[index]];
        this.from = start + buffer.buffer[index + 1];
        this.to = start + buffer.buffer[index + 2];
        return true;
    }
    /**
    @internal
    */
    yield(node) {
        if (!node)
            return false;
        if (node instanceof TreeNode) {
            this.buffer = null;
            return this.yieldNode(node);
        }
        this.buffer = node.context;
        return this.yieldBuf(node.index, node.type);
    }
    /**
    @internal
    */
    toString() {
        return this.buffer ? this.buffer.buffer.childString(this.index) : this._tree.toString();
    }
    /**
    @internal
    */
    enterChild(dir, pos, side) {
        if (!this.buffer)
            return this.yield(this._tree.nextChild(dir < 0 ? this._tree._tree.children.length - 1 : 0, dir, pos, side, this.mode));
        let { buffer } = this.buffer;
        let index = buffer.findChild(this.index + 4, buffer.buffer[this.index + 3], dir, pos - this.buffer.start, side);
        if (index < 0)
            return false;
        this.stack.push(this.index);
        return this.yieldBuf(index);
    }
    /**
    Move the cursor to this node's first child. When this returns
    false, the node has no child, and the cursor has not been moved.
    */
    firstChild() { return this.enterChild(1, 0, 4 /* Side.DontCare */); }
    /**
    Move the cursor to this node's last child.
    */
    lastChild() { return this.enterChild(-1, 0, 4 /* Side.DontCare */); }
    /**
    Move the cursor to the first child that ends after `pos`.
    */
    childAfter(pos) { return this.enterChild(1, pos, 2 /* Side.After */); }
    /**
    Move to the last child that starts before `pos`.
    */
    childBefore(pos) { return this.enterChild(-1, pos, -2 /* Side.Before */); }
    /**
    Move the cursor to the child around `pos`. If side is -1 the
    child may end at that position, when 1 it may start there. This
    will also enter [overlaid](#common.MountedTree.overlay)
    [mounted](#common.NodeProp^mounted) trees unless `overlays` is
    set to false.
    */
    enter(pos, side, mode = this.mode) {
        if (!this.buffer)
            return this.yield(this._tree.enter(pos, side, mode));
        return mode & exports.IterMode.ExcludeBuffers ? false : this.enterChild(1, pos, side);
    }
    /**
    Move to the node's parent node, if this isn't the top node.
    */
    parent() {
        if (!this.buffer)
            return this.yieldNode((this.mode & exports.IterMode.IncludeAnonymous) ? this._tree._parent : this._tree.parent);
        if (this.stack.length)
            return this.yieldBuf(this.stack.pop());
        let parent = (this.mode & exports.IterMode.IncludeAnonymous) ? this.buffer.parent : this.buffer.parent.nextSignificantParent();
        this.buffer = null;
        return this.yieldNode(parent);
    }
    /**
    @internal
    */
    sibling(dir) {
        if (!this.buffer)
            return !this._tree._parent ? false
                : this.yield(this._tree.index < 0 ? null
                    : this._tree._parent.nextChild(this._tree.index + dir, dir, 0, 4 /* Side.DontCare */, this.mode));
        let { buffer } = this.buffer, d = this.stack.length - 1;
        if (dir < 0) {
            let parentStart = d < 0 ? 0 : this.stack[d] + 4;
            if (this.index != parentStart)
                return this.yieldBuf(buffer.findChild(parentStart, this.index, -1, 0, 4 /* Side.DontCare */));
        }
        else {
            let after = buffer.buffer[this.index + 3];
            if (after < (d < 0 ? buffer.buffer.length : buffer.buffer[this.stack[d] + 3]))
                return this.yieldBuf(after);
        }
        return d < 0 ? this.yield(this.buffer.parent.nextChild(this.buffer.index + dir, dir, 0, 4 /* Side.DontCare */, this.mode)) : false;
    }
    /**
    Move to this node's next sibling, if any.
    */
    nextSibling() { return this.sibling(1); }
    /**
    Move to this node's previous sibling, if any.
    */
    prevSibling() { return this.sibling(-1); }
    atLastNode(dir) {
        let index, parent, { buffer } = this;
        if (buffer) {
            if (dir > 0) {
                if (this.index < buffer.buffer.buffer.length)
                    return false;
            }
            else {
                for (let i = 0; i < this.index; i++)
                    if (buffer.buffer.buffer[i + 3] < this.index)
                        return false;
            }
            ({ index, parent } = buffer);
        }
        else {
            ({ index, _parent: parent } = this._tree);
        }
        for (; parent; { index, _parent: parent } = parent) {
            if (index > -1)
                for (let i = index + dir, e = dir < 0 ? -1 : parent._tree.children.length; i != e; i += dir) {
                    let child = parent._tree.children[i];
                    if ((this.mode & exports.IterMode.IncludeAnonymous) ||
                        child instanceof TreeBuffer ||
                        !child.type.isAnonymous ||
                        hasChild(child))
                        return false;
                }
        }
        return true;
    }
    move(dir, enter) {
        if (enter && this.enterChild(dir, 0, 4 /* Side.DontCare */))
            return true;
        for (;;) {
            if (this.sibling(dir))
                return true;
            if (this.atLastNode(dir) || !this.parent())
                return false;
        }
    }
    /**
    Move to the next node in a
    [pre-order](https://en.wikipedia.org/wiki/Tree_traversal#Pre-order,_NLR)
    traversal, going from a node to its first child or, if the
    current node is empty or `enter` is false, its next sibling or
    the next sibling of the first parent node that has one.
    */
    next(enter = true) { return this.move(1, enter); }
    /**
    Move to the next node in a last-to-first pre-order traveral. A
    node is followed by its last child or, if it has none, its
    previous sibling or the previous sibling of the first parent
    node that has one.
    */
    prev(enter = true) { return this.move(-1, enter); }
    /**
    Move the cursor to the innermost node that covers `pos`. If
    `side` is -1, it will enter nodes that end at `pos`. If it is 1,
    it will enter nodes that start at `pos`.
    */
    moveTo(pos, side = 0) {
        // Move up to a node that actually holds the position, if possible
        while (this.from == this.to ||
            (side < 1 ? this.from >= pos : this.from > pos) ||
            (side > -1 ? this.to <= pos : this.to < pos))
            if (!this.parent())
                break;
        // Then scan down into child nodes as far as possible
        while (this.enterChild(1, pos, side)) { }
        return this;
    }
    /**
    Get a [syntax node](#common.SyntaxNode) at the cursor's current
    position.
    */
    get node() {
        if (!this.buffer)
            return this._tree;
        let cache = this.bufferNode, result = null, depth = 0;
        if (cache && cache.context == this.buffer) {
            scan: for (let index = this.index, d = this.stack.length; d >= 0;) {
                for (let c = cache; c; c = c._parent)
                    if (c.index == index) {
                        if (index == this.index)
                            return c;
                        result = c;
                        depth = d + 1;
                        break scan;
                    }
                index = this.stack[--d];
            }
        }
        for (let i = depth; i < this.stack.length; i++)
            result = new BufferNode(this.buffer, result, this.stack[i]);
        return this.bufferNode = new BufferNode(this.buffer, result, this.index);
    }
    /**
    Get the [tree](#common.Tree) that represents the current node, if
    any. Will return null when the node is in a [tree
    buffer](#common.TreeBuffer).
    */
    get tree() {
        return this.buffer ? null : this._tree._tree;
    }
    /**
    Iterate over the current node and all its descendants, calling
    `enter` when entering a node and `leave`, if given, when leaving
    one. When `enter` returns `false`, any children of that node are
    skipped, and `leave` isn't called for it.
    */
    iterate(enter, leave) {
        for (let depth = 0;;) {
            let mustLeave = false;
            if (this.type.isAnonymous || enter(this) !== false) {
                if (this.firstChild()) {
                    depth++;
                    continue;
                }
                if (!this.type.isAnonymous)
                    mustLeave = true;
            }
            for (;;) {
                if (mustLeave && leave)
                    leave(this);
                mustLeave = this.type.isAnonymous;
                if (this.nextSibling())
                    break;
                if (!depth)
                    return;
                this.parent();
                depth--;
                mustLeave = true;
            }
        }
    }
    /**
    Test whether the current node matches a given context—a sequence
    of direct parent node names. Empty strings in the context array
    are treated as wildcards.
    */
    matchContext(context) {
        if (!this.buffer)
            return matchNodeContext(this.node, context);
        let { buffer } = this.buffer, { types } = buffer.set;
        for (let i = context.length - 1, d = this.stack.length - 1; i >= 0; d--) {
            if (d < 0)
                return matchNodeContext(this.node, context, i);
            let type = types[buffer.buffer[this.stack[d]]];
            if (!type.isAnonymous) {
                if (context[i] && context[i] != type.name)
                    return false;
                i--;
            }
        }
        return true;
    }
}
function hasChild(tree) {
    return tree.children.some(ch => ch instanceof TreeBuffer || !ch.type.isAnonymous || hasChild(ch));
}
function buildTree(data) {
    var _a;
    let { buffer, nodeSet, maxBufferLength = DefaultBufferLength, reused = [], minRepeatType = nodeSet.types.length } = data;
    let cursor = Array.isArray(buffer) ? new FlatBufferCursor(buffer, buffer.length) : buffer;
    let types = nodeSet.types;
    let contextHash = 0, lookAhead = 0;
    function takeNode(parentStart, minPos, children, positions, inRepeat, depth) {
        let { id, start, end, size } = cursor;
        let lookAheadAtStart = lookAhead;
        while (size < 0) {
            cursor.next();
            if (size == -1 /* SpecialRecord.Reuse */) {
                let node = reused[id];
                children.push(node);
                positions.push(start - parentStart);
                return;
            }
            else if (size == -3 /* SpecialRecord.ContextChange */) { // Context change
                contextHash = id;
                return;
            }
            else if (size == -4 /* SpecialRecord.LookAhead */) {
                lookAhead = id;
                return;
            }
            else {
                throw new RangeError(`Unrecognized record size: ${size}`);
            }
        }
        let type = types[id], node, buffer;
        let startPos = start - parentStart;
        if (end - start <= maxBufferLength && (buffer = findBufferSize(cursor.pos - minPos, inRepeat))) {
            // Small enough for a buffer, and no reused nodes inside
            let data = new Uint16Array(buffer.size - buffer.skip);
            let endPos = cursor.pos - buffer.size, index = data.length;
            while (cursor.pos > endPos)
                index = copyToBuffer(buffer.start, data, index);
            node = new TreeBuffer(data, end - buffer.start, nodeSet);
            startPos = buffer.start - parentStart;
        }
        else { // Make it a node
            let endPos = cursor.pos - size;
            cursor.next();
            let localChildren = [], localPositions = [];
            let localInRepeat = id >= minRepeatType ? id : -1;
            let lastGroup = 0, lastEnd = end;
            while (cursor.pos > endPos) {
                if (localInRepeat >= 0 && cursor.id == localInRepeat && cursor.size >= 0) {
                    if (cursor.end <= lastEnd - maxBufferLength) {
                        makeRepeatLeaf(localChildren, localPositions, start, lastGroup, cursor.end, lastEnd, localInRepeat, lookAheadAtStart);
                        lastGroup = localChildren.length;
                        lastEnd = cursor.end;
                    }
                    cursor.next();
                }
                else if (depth > 2500 /* CutOff.Depth */) {
                    takeFlatNode(start, endPos, localChildren, localPositions);
                }
                else {
                    takeNode(start, endPos, localChildren, localPositions, localInRepeat, depth + 1);
                }
            }
            if (localInRepeat >= 0 && lastGroup > 0 && lastGroup < localChildren.length)
                makeRepeatLeaf(localChildren, localPositions, start, lastGroup, start, lastEnd, localInRepeat, lookAheadAtStart);
            localChildren.reverse();
            localPositions.reverse();
            if (localInRepeat > -1 && lastGroup > 0) {
                let make = makeBalanced(type);
                node = balanceRange(type, localChildren, localPositions, 0, localChildren.length, 0, end - start, make, make);
            }
            else {
                node = makeTree(type, localChildren, localPositions, end - start, lookAheadAtStart - end);
            }
        }
        children.push(node);
        positions.push(startPos);
    }
    function takeFlatNode(parentStart, minPos, children, positions) {
        let nodes = []; // Temporary, inverted array of leaf nodes found, with absolute positions
        let nodeCount = 0, stopAt = -1;
        while (cursor.pos > minPos) {
            let { id, start, end, size } = cursor;
            if (size > 4) { // Not a leaf
                cursor.next();
            }
            else if (stopAt > -1 && start < stopAt) {
                break;
            }
            else {
                if (stopAt < 0)
                    stopAt = end - maxBufferLength;
                nodes.push(id, start, end);
                nodeCount++;
                cursor.next();
            }
        }
        if (nodeCount) {
            let buffer = new Uint16Array(nodeCount * 4);
            let start = nodes[nodes.length - 2];
            for (let i = nodes.length - 3, j = 0; i >= 0; i -= 3) {
                buffer[j++] = nodes[i];
                buffer[j++] = nodes[i + 1] - start;
                buffer[j++] = nodes[i + 2] - start;
                buffer[j++] = j;
            }
            children.push(new TreeBuffer(buffer, nodes[2] - start, nodeSet));
            positions.push(start - parentStart);
        }
    }
    function makeBalanced(type) {
        return (children, positions, length) => {
            let lookAhead = 0, lastI = children.length - 1, last, lookAheadProp;
            if (lastI >= 0 && (last = children[lastI]) instanceof Tree) {
                if (!lastI && last.type == type && last.length == length)
                    return last;
                if (lookAheadProp = last.prop(NodeProp.lookAhead))
                    lookAhead = positions[lastI] + last.length + lookAheadProp;
            }
            return makeTree(type, children, positions, length, lookAhead);
        };
    }
    function makeRepeatLeaf(children, positions, base, i, from, to, type, lookAhead) {
        let localChildren = [], localPositions = [];
        while (children.length > i) {
            localChildren.push(children.pop());
            localPositions.push(positions.pop() + base - from);
        }
        children.push(makeTree(nodeSet.types[type], localChildren, localPositions, to - from, lookAhead - to));
        positions.push(from - base);
    }
    function makeTree(type, children, positions, length, lookAhead = 0, props) {
        if (contextHash) {
            let pair = [NodeProp.contextHash, contextHash];
            props = props ? [pair].concat(props) : [pair];
        }
        if (lookAhead > 25) {
            let pair = [NodeProp.lookAhead, lookAhead];
            props = props ? [pair].concat(props) : [pair];
        }
        return new Tree(type, children, positions, length, props);
    }
    function findBufferSize(maxSize, inRepeat) {
        // Scan through the buffer to find previous siblings that fit
        // together in a TreeBuffer, and don't contain any reused nodes
        // (which can't be stored in a buffer).
        // If `inRepeat` is > -1, ignore node boundaries of that type for
        // nesting, but make sure the end falls either at the start
        // (`maxSize`) or before such a node.
        let fork = cursor.fork();
        let size = 0, start = 0, skip = 0, minStart = fork.end - maxBufferLength;
        let result = { size: 0, start: 0, skip: 0 };
        scan: for (let minPos = fork.pos - maxSize; fork.pos > minPos;) {
            let nodeSize = fork.size;
            // Pretend nested repeat nodes of the same type don't exist
            if (fork.id == inRepeat && nodeSize >= 0) {
                // Except that we store the current state as a valid return
                // value.
                result.size = size;
                result.start = start;
                result.skip = skip;
                skip += 4;
                size += 4;
                fork.next();
                continue;
            }
            let startPos = fork.pos - nodeSize;
            if (nodeSize < 0 || startPos < minPos || fork.start < minStart)
                break;
            let localSkipped = fork.id >= minRepeatType ? 4 : 0;
            let nodeStart = fork.start;
            fork.next();
            while (fork.pos > startPos) {
                if (fork.size < 0) {
                    if (fork.size == -3 /* SpecialRecord.ContextChange */)
                        localSkipped += 4;
                    else
                        break scan;
                }
                else if (fork.id >= minRepeatType) {
                    localSkipped += 4;
                }
                fork.next();
            }
            start = nodeStart;
            size += nodeSize;
            skip += localSkipped;
        }
        if (inRepeat < 0 || size == maxSize) {
            result.size = size;
            result.start = start;
            result.skip = skip;
        }
        return result.size > 4 ? result : undefined;
    }
    function copyToBuffer(bufferStart, buffer, index) {
        let { id, start, end, size } = cursor;
        cursor.next();
        if (size >= 0 && id < minRepeatType) {
            let startIndex = index;
            if (size > 4) {
                let endPos = cursor.pos - (size - 4);
                while (cursor.pos > endPos)
                    index = copyToBuffer(bufferStart, buffer, index);
            }
            buffer[--index] = startIndex;
            buffer[--index] = end - bufferStart;
            buffer[--index] = start - bufferStart;
            buffer[--index] = id;
        }
        else if (size == -3 /* SpecialRecord.ContextChange */) {
            contextHash = id;
        }
        else if (size == -4 /* SpecialRecord.LookAhead */) {
            lookAhead = id;
        }
        return index;
    }
    let children = [], positions = [];
    while (cursor.pos > 0)
        takeNode(data.start || 0, data.bufferStart || 0, children, positions, -1, 0);
    let length = (_a = data.length) !== null && _a !== void 0 ? _a : (children.length ? positions[0] + children[0].length : 0);
    return new Tree(types[data.topID], children.reverse(), positions.reverse(), length);
}
const nodeSizeCache = new WeakMap;
function nodeSize(balanceType, node) {
    if (!balanceType.isAnonymous || node instanceof TreeBuffer || node.type != balanceType)
        return 1;
    let size = nodeSizeCache.get(node);
    if (size == null) {
        size = 1;
        for (let child of node.children) {
            if (child.type != balanceType || !(child instanceof Tree)) {
                size = 1;
                break;
            }
            size += nodeSize(balanceType, child);
        }
        nodeSizeCache.set(node, size);
    }
    return size;
}
function balanceRange(
// The type the balanced tree's inner nodes.
balanceType, 
// The direct children and their positions
children, positions, 
// The index range in children/positions to use
from, to, 
// The start position of the nodes, relative to their parent.
start, 
// Length of the outer node
length, 
// Function to build the top node of the balanced tree
mkTop, 
// Function to build internal nodes for the balanced tree
mkTree) {
    let total = 0;
    for (let i = from; i < to; i++)
        total += nodeSize(balanceType, children[i]);
    let maxChild = Math.ceil((total * 1.5) / 8 /* Balance.BranchFactor */);
    let localChildren = [], localPositions = [];
    function divide(children, positions, from, to, offset) {
        for (let i = from; i < to;) {
            let groupFrom = i, groupStart = positions[i], groupSize = nodeSize(balanceType, children[i]);
            i++;
            for (; i < to; i++) {
                let nextSize = nodeSize(balanceType, children[i]);
                if (groupSize + nextSize >= maxChild)
                    break;
                groupSize += nextSize;
            }
            if (i == groupFrom + 1) {
                if (groupSize > maxChild) {
                    let only = children[groupFrom]; // Only trees can have a size > 1
                    divide(only.children, only.positions, 0, only.children.length, positions[groupFrom] + offset);
                    continue;
                }
                localChildren.push(children[groupFrom]);
            }
            else {
                let length = positions[i - 1] + children[i - 1].length - groupStart;
                localChildren.push(balanceRange(balanceType, children, positions, groupFrom, i, groupStart, length, null, mkTree));
            }
            localPositions.push(groupStart + offset - start);
        }
    }
    divide(children, positions, from, to, 0);
    return (mkTop || mkTree)(localChildren, localPositions, length);
}
/**
Provides a way to associate values with pieces of trees. As long
as that part of the tree is reused, the associated values can be
retrieved from an updated tree.
*/
class NodeWeakMap {
    constructor() {
        this.map = new WeakMap();
    }
    setBuffer(buffer, index, value) {
        let inner = this.map.get(buffer);
        if (!inner)
            this.map.set(buffer, inner = new Map);
        inner.set(index, value);
    }
    getBuffer(buffer, index) {
        let inner = this.map.get(buffer);
        return inner && inner.get(index);
    }
    /**
    Set the value for this syntax node.
    */
    set(node, value) {
        if (node instanceof BufferNode)
            this.setBuffer(node.context.buffer, node.index, value);
        else if (node instanceof TreeNode)
            this.map.set(node.tree, value);
    }
    /**
    Retrieve value for this syntax node, if it exists in the map.
    */
    get(node) {
        return node instanceof BufferNode ? this.getBuffer(node.context.buffer, node.index)
            : node instanceof TreeNode ? this.map.get(node.tree) : undefined;
    }
    /**
    Set the value for the node that a cursor currently points to.
    */
    cursorSet(cursor, value) {
        if (cursor.buffer)
            this.setBuffer(cursor.buffer.buffer, cursor.index, value);
        else
            this.map.set(cursor.tree, value);
    }
    /**
    Retrieve the value for the node that a cursor currently points
    to.
    */
    cursorGet(cursor) {
        return cursor.buffer ? this.getBuffer(cursor.buffer.buffer, cursor.index) : this.map.get(cursor.tree);
    }
}

/**
Tree fragments are used during [incremental
parsing](#common.Parser.startParse) to track parts of old trees
that can be reused in a new parse. An array of fragments is used
to track regions of an old tree whose nodes might be reused in new
parses. Use the static
[`applyChanges`](#common.TreeFragment^applyChanges) method to
update fragments for document changes.
*/
class TreeFragment {
    /**
    Construct a tree fragment. You'll usually want to use
    [`addTree`](#common.TreeFragment^addTree) and
    [`applyChanges`](#common.TreeFragment^applyChanges) instead of
    calling this directly.
    */
    constructor(
    /**
    The start of the unchanged range pointed to by this fragment.
    This refers to an offset in the _updated_ document (as opposed
    to the original tree).
    */
    from, 
    /**
    The end of the unchanged range.
    */
    to, 
    /**
    The tree that this fragment is based on.
    */
    tree, 
    /**
    The offset between the fragment's tree and the document that
    this fragment can be used against. Add this when going from
    document to tree positions, subtract it to go from tree to
    document positions.
    */
    offset, openStart = false, openEnd = false) {
        this.from = from;
        this.to = to;
        this.tree = tree;
        this.offset = offset;
        this.open = (openStart ? 1 /* Open.Start */ : 0) | (openEnd ? 2 /* Open.End */ : 0);
    }
    /**
    Whether the start of the fragment represents the start of a
    parse, or the end of a change. (In the second case, it may not
    be safe to reuse some nodes at the start, depending on the
    parsing algorithm.)
    */
    get openStart() { return (this.open & 1 /* Open.Start */) > 0; }
    /**
    Whether the end of the fragment represents the end of a
    full-document parse, or the start of a change.
    */
    get openEnd() { return (this.open & 2 /* Open.End */) > 0; }
    /**
    Create a set of fragments from a freshly parsed tree, or update
    an existing set of fragments by replacing the ones that overlap
    with a tree with content from the new tree. When `partial` is
    true, the parse is treated as incomplete, and the resulting
    fragment has [`openEnd`](#common.TreeFragment.openEnd) set to
    true.
    */
    static addTree(tree, fragments = [], partial = false) {
        let result = [new TreeFragment(0, tree.length, tree, 0, false, partial)];
        for (let f of fragments)
            if (f.to > tree.length)
                result.push(f);
        return result;
    }
    /**
    Apply a set of edits to an array of fragments, removing or
    splitting fragments as necessary to remove edited ranges, and
    adjusting offsets for fragments that moved.
    */
    static applyChanges(fragments, changes, minGap = 128) {
        if (!changes.length)
            return fragments;
        let result = [];
        let fI = 1, nextF = fragments.length ? fragments[0] : null;
        for (let cI = 0, pos = 0, off = 0;; cI++) {
            let nextC = cI < changes.length ? changes[cI] : null;
            let nextPos = nextC ? nextC.fromA : 1e9;
            if (nextPos - pos >= minGap)
                while (nextF && nextF.from < nextPos) {
                    let cut = nextF;
                    if (pos >= cut.from || nextPos <= cut.to || off) {
                        let fFrom = Math.max(cut.from, pos) - off, fTo = Math.min(cut.to, nextPos) - off;
                        cut = fFrom >= fTo ? null : new TreeFragment(fFrom, fTo, cut.tree, cut.offset + off, cI > 0, !!nextC);
                    }
                    if (cut)
                        result.push(cut);
                    if (nextF.to > nextPos)
                        break;
                    nextF = fI < fragments.length ? fragments[fI++] : null;
                }
            if (!nextC)
                break;
            pos = nextC.toA;
            off = nextC.toA - nextC.toB;
        }
        return result;
    }
}
/**
A superclass that parsers should extend.
*/
class Parser {
    /**
    Start a parse, returning a [partial parse](#common.PartialParse)
    object. [`fragments`](#common.TreeFragment) can be passed in to
    make the parse incremental.
    
    By default, the entire input is parsed. You can pass `ranges`,
    which should be a sorted array of non-empty, non-overlapping
    ranges, to parse only those ranges. The tree returned in that
    case will start at `ranges[0].from`.
    */
    startParse(input, fragments, ranges) {
        if (typeof input == "string")
            input = new StringInput(input);
        ranges = !ranges ? [new Range(0, input.length)] : ranges.length ? ranges.map(r => new Range(r.from, r.to)) : [new Range(0, 0)];
        return this.createParse(input, fragments || [], ranges);
    }
    /**
    Run a full parse, returning the resulting tree.
    */
    parse(input, fragments, ranges) {
        let parse = this.startParse(input, fragments, ranges);
        for (;;) {
            let done = parse.advance();
            if (done)
                return done;
        }
    }
}
class StringInput {
    constructor(string) {
        this.string = string;
    }
    get length() { return this.string.length; }
    chunk(from) { return this.string.slice(from); }
    get lineChunks() { return false; }
    read(from, to) { return this.string.slice(from, to); }
}

/**
Create a parse wrapper that, after the inner parse completes,
scans its tree for mixed language regions with the `nest`
function, runs the resulting [inner parses](#common.NestedParse),
and then [mounts](#common.NodeProp^mounted) their results onto the
tree.
*/
function parseMixed(nest) {
    return (parse, input, fragments, ranges) => new MixedParse(parse, nest, input, fragments, ranges);
}
class InnerParse {
    constructor(parser, parse, overlay, target, from) {
        this.parser = parser;
        this.parse = parse;
        this.overlay = overlay;
        this.target = target;
        this.from = from;
    }
}
function checkRanges(ranges) {
    if (!ranges.length || ranges.some(r => r.from >= r.to))
        throw new RangeError("Invalid inner parse ranges given: " + JSON.stringify(ranges));
}
class ActiveOverlay {
    constructor(parser, predicate, mounts, index, start, target, prev) {
        this.parser = parser;
        this.predicate = predicate;
        this.mounts = mounts;
        this.index = index;
        this.start = start;
        this.target = target;
        this.prev = prev;
        this.depth = 0;
        this.ranges = [];
    }
}
const stoppedInner = new NodeProp({ perNode: true });
class MixedParse {
    constructor(base, nest, input, fragments, ranges) {
        this.nest = nest;
        this.input = input;
        this.fragments = fragments;
        this.ranges = ranges;
        this.inner = [];
        this.innerDone = 0;
        this.baseTree = null;
        this.stoppedAt = null;
        this.baseParse = base;
    }
    advance() {
        if (this.baseParse) {
            let done = this.baseParse.advance();
            if (!done)
                return null;
            this.baseParse = null;
            this.baseTree = done;
            this.startInner();
            if (this.stoppedAt != null)
                for (let inner of this.inner)
                    inner.parse.stopAt(this.stoppedAt);
        }
        if (this.innerDone == this.inner.length) {
            let result = this.baseTree;
            if (this.stoppedAt != null)
                result = new Tree(result.type, result.children, result.positions, result.length, result.propValues.concat([[stoppedInner, this.stoppedAt]]));
            return result;
        }
        let inner = this.inner[this.innerDone], done = inner.parse.advance();
        if (done) {
            this.innerDone++;
            // This is a somewhat dodgy but super helpful hack where we
            // patch up nodes created by the inner parse (and thus
            // presumably not aliased anywhere else) to hold the information
            // about the inner parse.
            let props = Object.assign(Object.create(null), inner.target.props);
            props[NodeProp.mounted.id] = new MountedTree(done, inner.overlay, inner.parser);
            inner.target.props = props;
        }
        return null;
    }
    get parsedPos() {
        if (this.baseParse)
            return 0;
        let pos = this.input.length;
        for (let i = this.innerDone; i < this.inner.length; i++) {
            if (this.inner[i].from < pos)
                pos = Math.min(pos, this.inner[i].parse.parsedPos);
        }
        return pos;
    }
    stopAt(pos) {
        this.stoppedAt = pos;
        if (this.baseParse)
            this.baseParse.stopAt(pos);
        else
            for (let i = this.innerDone; i < this.inner.length; i++)
                this.inner[i].parse.stopAt(pos);
    }
    startInner() {
        let fragmentCursor = new FragmentCursor(this.fragments);
        let overlay = null;
        let covered = null;
        let cursor = new TreeCursor(new TreeNode(this.baseTree, this.ranges[0].from, 0, null), exports.IterMode.IncludeAnonymous | exports.IterMode.IgnoreMounts);
        scan: for (let nest, isCovered;;) {
            let enter = true, range;
            if (this.stoppedAt != null && cursor.from >= this.stoppedAt) {
                enter = false;
            }
            else if (fragmentCursor.hasNode(cursor)) {
                if (overlay) {
                    let match = overlay.mounts.find(m => m.frag.from <= cursor.from && m.frag.to >= cursor.to && m.mount.overlay);
                    if (match)
                        for (let r of match.mount.overlay) {
                            let from = r.from + match.pos, to = r.to + match.pos;
                            if (from >= cursor.from && to <= cursor.to && !overlay.ranges.some(r => r.from < to && r.to > from))
                                overlay.ranges.push({ from, to });
                        }
                }
                enter = false;
            }
            else if (covered && (isCovered = checkCover(covered.ranges, cursor.from, cursor.to))) {
                enter = isCovered != 2 /* Cover.Full */;
            }
            else if (!cursor.type.isAnonymous && (nest = this.nest(cursor, this.input)) &&
                (cursor.from < cursor.to || !nest.overlay)) {
                if (!cursor.tree)
                    materialize(cursor);
                let oldMounts = fragmentCursor.findMounts(cursor.from, nest.parser);
                if (typeof nest.overlay == "function") {
                    overlay = new ActiveOverlay(nest.parser, nest.overlay, oldMounts, this.inner.length, cursor.from, cursor.tree, overlay);
                }
                else {
                    let ranges = punchRanges(this.ranges, nest.overlay ||
                        (cursor.from < cursor.to ? [new Range(cursor.from, cursor.to)] : []));
                    if (ranges.length)
                        checkRanges(ranges);
                    if (ranges.length || !nest.overlay)
                        this.inner.push(new InnerParse(nest.parser, ranges.length ? nest.parser.startParse(this.input, enterFragments(oldMounts, ranges), ranges)
                            : nest.parser.startParse(""), nest.overlay ? nest.overlay.map(r => new Range(r.from - cursor.from, r.to - cursor.from)) : null, cursor.tree, ranges.length ? ranges[0].from : cursor.from));
                    if (!nest.overlay)
                        enter = false;
                    else if (ranges.length)
                        covered = { ranges, depth: 0, prev: covered };
                }
            }
            else if (overlay && (range = overlay.predicate(cursor))) {
                if (range === true)
                    range = new Range(cursor.from, cursor.to);
                if (range.from < range.to)
                    overlay.ranges.push(range);
            }
            if (enter && cursor.firstChild()) {
                if (overlay)
                    overlay.depth++;
                if (covered)
                    covered.depth++;
            }
            else {
                for (;;) {
                    if (cursor.nextSibling())
                        break;
                    if (!cursor.parent())
                        break scan;
                    if (overlay && !--overlay.depth) {
                        let ranges = punchRanges(this.ranges, overlay.ranges);
                        if (ranges.length) {
                            checkRanges(ranges);
                            this.inner.splice(overlay.index, 0, new InnerParse(overlay.parser, overlay.parser.startParse(this.input, enterFragments(overlay.mounts, ranges), ranges), overlay.ranges.map(r => new Range(r.from - overlay.start, r.to - overlay.start)), overlay.target, ranges[0].from));
                        }
                        overlay = overlay.prev;
                    }
                    if (covered && !--covered.depth)
                        covered = covered.prev;
                }
            }
        }
    }
}
function checkCover(covered, from, to) {
    for (let range of covered) {
        if (range.from >= to)
            break;
        if (range.to > from)
            return range.from <= from && range.to >= to ? 2 /* Cover.Full */ : 1 /* Cover.Partial */;
    }
    return 0 /* Cover.None */;
}
// Take a piece of buffer and convert it into a stand-alone
// TreeBuffer.
function sliceBuf(buf, startI, endI, nodes, positions, off) {
    if (startI < endI) {
        let from = buf.buffer[startI + 1];
        nodes.push(buf.slice(startI, endI, from));
        positions.push(from - off);
    }
}
// This function takes a node that's in a buffer, and converts it, and
// its parent buffer nodes, into a Tree. This is again acting on the
// assumption that the trees and buffers have been constructed by the
// parse that was ran via the mix parser, and thus aren't shared with
// any other code, making violations of the immutability safe.
function materialize(cursor) {
    let { node } = cursor, stack = [];
    let buffer = node.context.buffer;
    // Scan up to the nearest tree
    do {
        stack.push(cursor.index);
        cursor.parent();
    } while (!cursor.tree);
    // Find the index of the buffer in that tree
    let base = cursor.tree, i = base.children.indexOf(buffer);
    let buf = base.children[i], b = buf.buffer, newStack = [i];
    // Split a level in the buffer, putting the nodes before and after
    // the child that contains `node` into new buffers.
    function split(startI, endI, type, innerOffset, length, stackPos) {
        let targetI = stack[stackPos];
        let children = [], positions = [];
        sliceBuf(buf, startI, targetI, children, positions, innerOffset);
        let from = b[targetI + 1], to = b[targetI + 2];
        newStack.push(children.length);
        let child = stackPos
            ? split(targetI + 4, b[targetI + 3], buf.set.types[b[targetI]], from, to - from, stackPos - 1)
            : node.toTree();
        children.push(child);
        positions.push(from - innerOffset);
        sliceBuf(buf, b[targetI + 3], endI, children, positions, innerOffset);
        return new Tree(type, children, positions, length);
    }
    base.children[i] = split(0, b.length, NodeType.none, 0, buf.length, stack.length - 1);
    // Move the cursor back to the target node
    for (let index of newStack) {
        let tree = cursor.tree.children[index], pos = cursor.tree.positions[index];
        cursor.yield(new TreeNode(tree, pos + cursor.from, index, cursor._tree));
    }
}
class StructureCursor {
    constructor(root, offset) {
        this.offset = offset;
        this.done = false;
        this.cursor = root.cursor(exports.IterMode.IncludeAnonymous | exports.IterMode.IgnoreMounts);
    }
    // Move to the first node (in pre-order) that starts at or after `pos`.
    moveTo(pos) {
        let { cursor } = this, p = pos - this.offset;
        while (!this.done && cursor.from < p) {
            if (cursor.to >= pos && cursor.enter(p, 1, exports.IterMode.IgnoreOverlays | exports.IterMode.ExcludeBuffers)) ;
            else if (!cursor.next(false))
                this.done = true;
        }
    }
    hasNode(cursor) {
        this.moveTo(cursor.from);
        if (!this.done && this.cursor.from + this.offset == cursor.from && this.cursor.tree) {
            for (let tree = this.cursor.tree;;) {
                if (tree == cursor.tree)
                    return true;
                if (tree.children.length && tree.positions[0] == 0 && tree.children[0] instanceof Tree)
                    tree = tree.children[0];
                else
                    break;
            }
        }
        return false;
    }
}
class FragmentCursor {
    constructor(fragments) {
        var _a;
        this.fragments = fragments;
        this.curTo = 0;
        this.fragI = 0;
        if (fragments.length) {
            let first = this.curFrag = fragments[0];
            this.curTo = (_a = first.tree.prop(stoppedInner)) !== null && _a !== void 0 ? _a : first.to;
            this.inner = new StructureCursor(first.tree, -first.offset);
        }
        else {
            this.curFrag = this.inner = null;
        }
    }
    hasNode(node) {
        while (this.curFrag && node.from >= this.curTo)
            this.nextFrag();
        return this.curFrag && this.curFrag.from <= node.from && this.curTo >= node.to && this.inner.hasNode(node);
    }
    nextFrag() {
        var _a;
        this.fragI++;
        if (this.fragI == this.fragments.length) {
            this.curFrag = this.inner = null;
        }
        else {
            let frag = this.curFrag = this.fragments[this.fragI];
            this.curTo = (_a = frag.tree.prop(stoppedInner)) !== null && _a !== void 0 ? _a : frag.to;
            this.inner = new StructureCursor(frag.tree, -frag.offset);
        }
    }
    findMounts(pos, parser) {
        var _a;
        let result = [];
        if (this.inner) {
            this.inner.cursor.moveTo(pos, 1);
            for (let pos = this.inner.cursor.node; pos; pos = pos.parent) {
                let mount = (_a = pos.tree) === null || _a === void 0 ? void 0 : _a.prop(NodeProp.mounted);
                if (mount && mount.parser == parser) {
                    for (let i = this.fragI; i < this.fragments.length; i++) {
                        let frag = this.fragments[i];
                        if (frag.from >= pos.to)
                            break;
                        if (frag.tree == this.curFrag.tree)
                            result.push({
                                frag,
                                pos: pos.from - frag.offset,
                                mount
                            });
                    }
                }
            }
        }
        return result;
    }
}
function punchRanges(outer, ranges) {
    let copy = null, current = ranges;
    for (let i = 1, j = 0; i < outer.length; i++) {
        let gapFrom = outer[i - 1].to, gapTo = outer[i].from;
        for (; j < current.length; j++) {
            let r = current[j];
            if (r.from >= gapTo)
                break;
            if (r.to <= gapFrom)
                continue;
            if (!copy)
                current = copy = ranges.slice();
            if (r.from < gapFrom) {
                copy[j] = new Range(r.from, gapFrom);
                if (r.to > gapTo)
                    copy.splice(j + 1, 0, new Range(gapTo, r.to));
            }
            else if (r.to > gapTo) {
                copy[j--] = new Range(gapTo, r.to);
            }
            else {
                copy.splice(j--, 1);
            }
        }
    }
    return current;
}
function findCoverChanges(a, b, from, to) {
    let iA = 0, iB = 0, inA = false, inB = false, pos = -1e9;
    let result = [];
    for (;;) {
        let nextA = iA == a.length ? 1e9 : inA ? a[iA].to : a[iA].from;
        let nextB = iB == b.length ? 1e9 : inB ? b[iB].to : b[iB].from;
        if (inA != inB) {
            let start = Math.max(pos, from), end = Math.min(nextA, nextB, to);
            if (start < end)
                result.push(new Range(start, end));
        }
        pos = Math.min(nextA, nextB);
        if (pos == 1e9)
            break;
        if (nextA == pos) {
            if (!inA)
                inA = true;
            else {
                inA = false;
                iA++;
            }
        }
        if (nextB == pos) {
            if (!inB)
                inB = true;
            else {
                inB = false;
                iB++;
            }
        }
    }
    return result;
}
// Given a number of fragments for the outer tree, and a set of ranges
// to parse, find fragments for inner trees mounted around those
// ranges, if any.
function enterFragments(mounts, ranges) {
    let result = [];
    for (let { pos, mount, frag } of mounts) {
        let startPos = pos + (mount.overlay ? mount.overlay[0].from : 0), endPos = startPos + mount.tree.length;
        let from = Math.max(frag.from, startPos), to = Math.min(frag.to, endPos);
        if (mount.overlay) {
            let overlay = mount.overlay.map(r => new Range(r.from + pos, r.to + pos));
            let changes = findCoverChanges(ranges, overlay, from, to);
            for (let i = 0, pos = from;; i++) {
                let last = i == changes.length, end = last ? to : changes[i].from;
                if (end > pos)
                    result.push(new TreeFragment(pos, end, mount.tree, -startPos, frag.from >= pos || frag.openStart, frag.to <= end || frag.openEnd));
                if (last)
                    break;
                pos = changes[i].to;
            }
        }
        else {
            result.push(new TreeFragment(from, to, mount.tree, -startPos, frag.from >= startPos || frag.openStart, frag.to <= endPos || frag.openEnd));
        }
    }
    return result;
}

exports.DefaultBufferLength = DefaultBufferLength;
exports.MountedTree = MountedTree;
exports.NodeProp = NodeProp;
exports.NodeSet = NodeSet;
exports.NodeType = NodeType;
exports.NodeWeakMap = NodeWeakMap;
exports.Parser = Parser;
exports.Tree = Tree;
exports.TreeBuffer = TreeBuffer;
exports.TreeCursor = TreeCursor;
exports.TreeFragment = TreeFragment;
exports.parseMixed = parseMixed;