antlr-ng/dist/src/tree/TreeIterator.js

Next generation ANTLR Tool

var __defProp = Object.defineProperty;
var __name = (target, value) => __defProp(target, "name", { value, configurable: true });
import { CommonToken, Token } from "antlr4ng";
import { Constants } from "../Constants.js";
import { CommonTree } from "./CommonTree.js";
class TreeIterator {
  static {
    __name(this, "TreeIterator");
  }
  /** Navigation nodes to return during walk and at end. */
  static up = new CommonTree(CommonToken.fromType(Constants.Up, "UP"));
  static down = new CommonTree(CommonToken.fromType(Constants.Down, "DOWN"));
  static eof = new CommonTree(CommonToken.fromType(Token.EOF, "EOF"));
  root;
  tree;
  firstTime = true;
  /** If we emit UP/DOWN nodes, we need to spit out multiple nodes per next() call. */
  nodes = [];
  constructor(tree) {
    this.tree = tree;
    this.root = tree;
  }
  reset() {
    this.firstTime = true;
    this.tree = this.root;
    this.nodes.length = 0;
  }
  hasNext() {
    if (this.firstTime) {
      return this.root !== void 0;
    }
    if (this.nodes.length > 0) {
      return true;
    }
    if (this.tree === void 0) {
      return false;
    }
    if (this.tree.children.length > 0) {
      return true;
    }
    return this.tree.parent !== null;
  }
  nextTree() {
    if (this.firstTime) {
      this.firstTime = false;
      if (this.tree?.children.length === 0) {
        this.nodes.push(TreeIterator.eof);
        return this.tree;
      }
      return this.tree;
    }
    if (this.nodes.length > 0) {
      return this.nodes.shift();
    }
    if (this.tree === void 0) {
      return TreeIterator.eof;
    }
    if (this.tree.children.length > 0) {
      this.tree = this.tree.children[0];
      this.nodes.push(this.tree);
      return TreeIterator.down;
    }
    let parent = this.tree.parent;
    while (parent !== null && this.tree.childIndex + 1 >= parent.children.length) {
      this.nodes.push(TreeIterator.up);
      this.tree = parent;
      parent = this.tree.parent;
    }
    if (parent === null) {
      this.tree = void 0;
      this.nodes.push(TreeIterator.eof);
      return this.nodes.shift();
    }
    const nextSiblingIndex = this.tree.childIndex + 1;
    this.tree = parent.children[nextSiblingIndex];
    this.nodes.push(this.tree);
    return this.nodes.shift();
  }
  remove() {
    throw new Error("Remove is unsupported");
  }
}
export {
  TreeIterator
};