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'use strict';
// --------------------------------------------------------------------// Imports// --------------------------------------------------------------------
const Interval = require('./Interval');const common = require('./common');
// --------------------------------------------------------------------// Private stuff// --------------------------------------------------------------------
// Unicode characters that are used in the `toString` output.const BALLOT_X = '\u2717';const CHECK_MARK = '\u2713';const DOT_OPERATOR = '\u22C5';const RIGHTWARDS_DOUBLE_ARROW = '\u21D2';const SYMBOL_FOR_HORIZONTAL_TABULATION = '\u2409';const SYMBOL_FOR_LINE_FEED = '\u240A';const SYMBOL_FOR_CARRIAGE_RETURN = '\u240D';
const Flags = {  succeeded: 1 << 0,  isRootNode: 1 << 1,  isImplicitSpaces: 1 << 2,  isMemoized: 1 << 3,  isHeadOfLeftRecursion: 1 << 4,  terminatesLR: 1 << 5,};
function spaces(n) {  return common.repeat(' ', n).join('');}
// Return a string representation of a portion of `input` at offset `pos`.// The result will contain exactly `len` characters.function getInputExcerpt(input, pos, len) {  const excerpt = asEscapedString(input.slice(pos, pos + len));
  // Pad the output if necessary.  if (excerpt.length < len) {    return excerpt + common.repeat(' ', len - excerpt.length).join('');  }  return excerpt;}
function asEscapedString(obj) {  if (typeof obj === 'string') {    // Replace non-printable characters with visible symbols.    return obj        .replace(/ /g, DOT_OPERATOR)        .replace(/\t/g, SYMBOL_FOR_HORIZONTAL_TABULATION)        .replace(/\n/g, SYMBOL_FOR_LINE_FEED)        .replace(/\r/g, SYMBOL_FOR_CARRIAGE_RETURN);  }  return String(obj);}
// ----------------- Trace -----------------
function Trace(input, pos1, pos2, expr, succeeded, bindings, optChildren) {  this.input = input;  this.pos = this.pos1 = pos1;  this.pos2 = pos2;  this.source = new Interval(input, pos1, pos2);  this.expr = expr;  this.bindings = bindings;  this.children = optChildren || [];  this.terminatingLREntry = null;
  this._flags = succeeded ? Flags.succeeded : 0;}
// A value that can be returned from visitor functions to indicate that a// node should not be recursed into.Trace.prototype.SKIP = {};
Object.defineProperty(Trace.prototype, 'displayString', {  get() {    return this.expr.toDisplayString();  },});
// For convenience, create a getter and setter for the boolean flags in `Flags`.Object.keys(Flags).forEach(name => {  const mask = Flags[name];  Object.defineProperty(Trace.prototype, name, {    get() {      return (this._flags & mask) !== 0;    },    set(val) {      if (val) {        this._flags |= mask;      } else {        this._flags &= ~mask;      }    },  });});
Trace.prototype.clone = function() {  return this.cloneWithExpr(this.expr);};
Trace.prototype.cloneWithExpr = function(expr) {  const ans = new Trace(      this.input,      this.pos,      this.pos2,      expr,      this.succeeded,      this.bindings,      this.children  );
  ans.isHeadOfLeftRecursion = this.isHeadOfLeftRecursion;  ans.isImplicitSpaces = this.isImplicitSpaces;  ans.isMemoized = this.isMemoized;  ans.isRootNode = this.isRootNode;  ans.terminatesLR = this.terminatesLR;  ans.terminatingLREntry = this.terminatingLREntry;  return ans;};
// Record the trace information for the terminating condition of the LR loop.Trace.prototype.recordLRTermination = function(ruleBodyTrace, value) {  this.terminatingLREntry = new Trace(      this.input,      this.pos,      this.pos2,      this.expr,      false,      [value],      [ruleBodyTrace]  );  this.terminatingLREntry.terminatesLR = true;};
// Recursively traverse this trace node and all its descendents, calling a visitor function// for each node that is visited. If `vistorObjOrFn` is an object, then its 'enter' property// is a function to call before visiting the children of a node, and its 'exit' property is// a function to call afterwards. If `visitorObjOrFn` is a function, it represents the 'enter'// function.//// The functions are called with three arguments: the Trace node, its parent Trace, and a number// representing the depth of the node in the tree. (The root node has depth 0.) `optThisArg`, if// specified, is the value to use for `this` when executing the visitor functions.Trace.prototype.walk = function(visitorObjOrFn, optThisArg) {  let visitor = visitorObjOrFn;  if (typeof visitor === 'function') {    visitor = {enter: visitor};  }
  function _walk(node, parent, depth) {    let recurse = true;    if (visitor.enter) {      if (visitor.enter.call(optThisArg, node, parent, depth) === Trace.prototype.SKIP) {        recurse = false;      }    }    if (recurse) {      node.children.forEach(child => {        _walk(child, node, depth + 1);      });      if (visitor.exit) {        visitor.exit.call(optThisArg, node, parent, depth);      }    }  }  if (this.isRootNode) {    // Don't visit the root node itself, only its children.    this.children.forEach(c => {      _walk(c, null, 0);    });  } else {    _walk(this, null, 0);  }};
// Return a string representation of the trace.// Sample://     12⋅+⋅2⋅*⋅3 ✓ exp ⇒  "12"//     12⋅+⋅2⋅*⋅3   ✓ addExp (LR) ⇒  "12"//     12⋅+⋅2⋅*⋅3       ✗ addExp_plusTrace.prototype.toString = function() {  const sb = new common.StringBuffer();  this.walk((node, parent, depth) => {    if (!node) {      return this.SKIP;    }    const ctorName = node.expr.constructor.name;    // Don't print anything for Alt nodes.    if (ctorName === 'Alt') {      return; // eslint-disable-line consistent-return    }    sb.append(getInputExcerpt(node.input, node.pos, 10) + spaces(depth * 2 + 1));    sb.append((node.succeeded ? CHECK_MARK : BALLOT_X) + ' ' + node.displayString);    if (node.isHeadOfLeftRecursion) {      sb.append(' (LR)');    }    if (node.succeeded) {      const contents = asEscapedString(node.source.contents);      sb.append(' ' + RIGHTWARDS_DOUBLE_ARROW + '  ');      sb.append(typeof contents === 'string' ? '"' + contents + '"' : contents);    }    sb.append('\n');  });  return sb.contents();};
// --------------------------------------------------------------------// Exports// --------------------------------------------------------------------
module.exports = Trace;