The Tor Browser: browser/devtools/shared/Parser.jsm@6474c204b198 (annotated)

browser/devtools/shared/Parser.jsm@6474c204b198 (annotated)

browser/devtools/shared/Parser.jsm

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: javascript; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ft=javascript ts=2 et sw=2 tw=80: */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 "use strict";
 const Ci = Components.interfaces;
 const Cu = Components.utils;
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 const { DevToolsUtils } = Cu.import("resource://gre/modules/devtools/DevToolsUtils.jsm", {});
 XPCOMUtils.defineLazyModuleGetter(this,
   "Reflect", "resource://gre/modules/reflect.jsm");
 this.EXPORTED_SYMBOLS = ["Parser", "ParserHelpers", "SyntaxTreeVisitor"];
 /**
  * A JS parser using the reflection API.
  */
 this.Parser = function Parser() {
   this._cache = new Map();
   this.errors = [];
 };
 Parser.prototype = {
   /**
    * Gets a collection of parser methods for a specified source.
    *
    * @param string aSource
    *        The source text content.
    * @param string aUrl [optional]
    *        The source url. The AST nodes will be cached, so you can use this
    *        identifier to avoid parsing the whole source again.
    */
   get: function(aSource, aUrl = "") {
     // Try to use the cached AST nodes, to avoid useless parsing operations.
     if (this._cache.has(aUrl)) {
       return this._cache.get(aUrl);
     }
     // The source may not necessarily be JS, in which case we need to extract
     // all the scripts. Fastest/easiest way is with a regular expression.
     // Don't worry, the rules of using a <script> tag are really strict,
     // this will work.
     let regexp = /<script[^>]*>([^]*?)<\/script\s*>/gim;
     let syntaxTrees = [];
     let scriptMatches = [];
     let scriptMatch;
     if (aSource.match(/^\s*</)) {
       // First non whitespace character is &lt, so most definitely HTML.
       while (scriptMatch = regexp.exec(aSource)) {
         scriptMatches.push(scriptMatch[1]); // Contents are captured at index 1.
       }
     }
     // If there are no script matches, send the whole source directly to the
     // reflection API to generate the AST nodes.
     if (!scriptMatches.length) {
       // Reflect.parse throws when encounters a syntax error.
       try {
         let nodes = Reflect.parse(aSource);
         let length = aSource.length;
         syntaxTrees.push(new SyntaxTree(nodes, aUrl, length));
       } catch (e) {
         this.errors.push(e);
         DevToolsUtils.reportException(aUrl, e);
       }
     }
     // Generate the AST nodes for each script.
     else {
       for (let script of scriptMatches) {
         // Reflect.parse throws when encounters a syntax error.
         try {
           let nodes = Reflect.parse(script);
           let offset = aSource.indexOf(script);
           let length = script.length;
           syntaxTrees.push(new SyntaxTree(nodes, aUrl, length, offset));
         } catch (e) {
           this.errors.push(e);
           DevToolsUtils.reportException(aUrl, e);
         }
       }
     }
     let pool = new SyntaxTreesPool(syntaxTrees, aUrl);
     // Cache the syntax trees pool by the specified url. This is entirely
     // optional, but it's strongly encouraged to cache ASTs because
     // generating them can be costly with big/complex sources.
     if (aUrl) {
       this._cache.set(aUrl, pool);
     }
     return pool;
   },
   /**
    * Clears all the parsed sources from cache.
    */
   clearCache: function() {
     this._cache.clear();
   },
   /**
    * Clears the AST for a particular source.
    *
    * @param String aUrl
    *        The URL of the source that is being cleared.
    */
   clearSource: function(aUrl) {
     this._cache.delete(aUrl);
   },
   _cache: null,
   errors: null
 };
 /**
  * A pool handling a collection of AST nodes generated by the reflection API.
  *
  * @param object aSyntaxTrees
  *        A collection of AST nodes generated for a source.
  * @param string aUrl [optional]
  *        The source url.
  */
 function SyntaxTreesPool(aSyntaxTrees, aUrl = "<unknown>") {
   this._trees = aSyntaxTrees;
   this._url = aUrl;
   this._cache = new Map();
 }
 SyntaxTreesPool.prototype = {
   /**
    * @see SyntaxTree.prototype.getIdentifierAt
    */
   getIdentifierAt: function({ line, column, scriptIndex, ignoreLiterals }) {
     return this._call("getIdentifierAt", scriptIndex, line, column, ignoreLiterals)[0];
   },
   /**
    * @see SyntaxTree.prototype.getNamedFunctionDefinitions
    */
   getNamedFunctionDefinitions: function(aSubstring) {
     return this._call("getNamedFunctionDefinitions", -1, aSubstring);
   },
   /**
    * Gets the total number of scripts in the parent source.
    * @return number
    */
   get scriptCount() {
     return this._trees.length;
   },
   /**
    * Finds the start and length of the script containing the specified offset
    * relative to its parent source.
    *
    * @param number aOffset
    *        The offset relative to the parent source.
    * @return object
    *         The offset and length relative to the enclosing script.
    */
   getScriptInfo: function(aOffset) {
     let info = { start: -1, length: -1, index: -1 };
     for (let { offset, length } of this._trees) {
       info.index++;
       if (offset <= aOffset && offset + length >= aOffset) {
         info.start = offset;
         info.length = length;
         return info;
       }
     }
     info.index = -1;
     return info;
   },
   /**
    * Handles a request for a specific or all known syntax trees.
    *
    * @param string aFunction
    *        The function name to call on the SyntaxTree instances.
    * @param number aSyntaxTreeIndex
    *        The syntax tree for which to handle the request. If the tree at
    *        the specified index isn't found, the accumulated results for all
    *        syntax trees are returned.
    * @param any aParams
    *        Any kind params to pass to the request function.
    * @return array
    *         The results given by all known syntax trees.
    */
   _call: function(aFunction, aSyntaxTreeIndex, ...aParams) {
     let results = [];
     let requestId = [aFunction, aSyntaxTreeIndex, aParams].toSource();
     if (this._cache.has(requestId)) {
       return this._cache.get(requestId);
     }
     let requestedTree = this._trees[aSyntaxTreeIndex];
     let targettedTrees = requestedTree ? [requestedTree] : this._trees;
     for (let syntaxTree of targettedTrees) {
       try {
         let parseResults = syntaxTree[aFunction].apply(syntaxTree, aParams);
         if (parseResults) {
           parseResults.sourceUrl = syntaxTree.url;
           parseResults.scriptLength = syntaxTree.length;
           parseResults.scriptOffset = syntaxTree.offset;
           results.push(parseResults);
         }
       } catch (e) {
         // Can't guarantee that the tree traversal logic is forever perfect :)
         // Language features may be added, in which case the recursive methods
         // need to be updated. If an exception is thrown here, file a bug.
         DevToolsUtils.reportException("Syntax tree visitor for " + aUrl, e);
       }
     }
     this._cache.set(requestId, results);
     return results;
   },
   _trees: null,
   _cache: null
 };
 /**
  * A collection of AST nodes generated by the reflection API.
  *
  * @param object aNodes
  *        The AST nodes.
  * @param string aUrl
  *        The source url.
  * @param number aLength
  *        The total number of chars of the parsed script in the parent source.
  * @param number aOffset [optional]
  *        The char offset of the parsed script in the parent source.
  */
 function SyntaxTree(aNodes, aUrl, aLength, aOffset = 0) {
   this.AST = aNodes;
   this.url = aUrl;
   this.length = aLength;
   this.offset = aOffset;
 };
 SyntaxTree.prototype = {
   /**
    * Gets the identifier at the specified location.
    *
    * @param number aLine
    *        The line in the source.
    * @param number aColumn
    *        The column in the source.
    * @param boolean aIgnoreLiterals
    *        Specifies if alone literals should be ignored.
    * @return object
    *         An object containing identifier information as { name, location,
    *         evalString } properties, or null if nothing is found.
    */
   getIdentifierAt: function(aLine, aColumn, aIgnoreLiterals) {
     let info = null;
     SyntaxTreeVisitor.walk(this.AST, {
       /**
        * Callback invoked for each identifier node.
        * @param Node aNode
        */
       onIdentifier: function(aNode) {
         if (ParserHelpers.nodeContainsPoint(aNode, aLine, aColumn)) {
           info = {
             name: aNode.name,
             location: ParserHelpers.getNodeLocation(aNode),
             evalString: ParserHelpers.getIdentifierEvalString(aNode)
           };
           // Abruptly halt walking the syntax tree.
           SyntaxTreeVisitor.break = true;
         }
       },
       /**
        * Callback invoked for each literal node.
        * @param Node aNode
        */
       onLiteral: function(aNode) {
         if (!aIgnoreLiterals) {
           this.onIdentifier(aNode);
         }
       },
       /**
        * Callback invoked for each 'this' node.
        * @param Node aNode
        */
       onThisExpression: function(aNode) {
         this.onIdentifier(aNode);
       }
     });
     return info;
   },
   /**
    * Searches for all function definitions (declarations and expressions)
    * whose names (or inferred names) contain a string.
    *
    * @param string aSubstring
    *        The string to be contained in the function name (or inferred name).
    *        Can be an empty string to match all functions.
    * @return array
    *         All the matching function declarations and expressions, as
    *         { functionName, functionLocation ... } object hashes.
    */
   getNamedFunctionDefinitions: function(aSubstring) {
     let lowerCaseToken = aSubstring.toLowerCase();
     let store = [];
     SyntaxTreeVisitor.walk(this.AST, {
       /**
        * Callback invoked for each function declaration node.
        * @param Node aNode
        */
       onFunctionDeclaration: function(aNode) {
         let functionName = aNode.id.name;
         if (functionName.toLowerCase().contains(lowerCaseToken)) {
           store.push({
             functionName: functionName,
             functionLocation: ParserHelpers.getNodeLocation(aNode)
           });
         }
       },
       /**
        * Callback invoked for each function expression node.
        * @param Node aNode
        */
       onFunctionExpression: function(aNode) {
         // Function expressions don't necessarily have a name.
         let functionName = aNode.id ? aNode.id.name : "";
         let functionLocation = ParserHelpers.getNodeLocation(aNode);
         // Infer the function's name from an enclosing syntax tree node.
         let inferredInfo = ParserHelpers.inferFunctionExpressionInfo(aNode);
         let inferredName = inferredInfo.name;
         let inferredChain = inferredInfo.chain;
         let inferredLocation = inferredInfo.loc;
         // Current node may be part of a larger assignment expression stack.
         if (aNode._parent.type == "AssignmentExpression") {
           this.onFunctionExpression(aNode._parent);
         }
         if ((functionName && functionName.toLowerCase().contains(lowerCaseToken)) ||
             (inferredName && inferredName.toLowerCase().contains(lowerCaseToken))) {
           store.push({
             functionName: functionName,
             functionLocation: functionLocation,
             inferredName: inferredName,
             inferredChain: inferredChain,
             inferredLocation: inferredLocation
           });
         }
       },
       /**
        * Callback invoked for each arrow expression node.
        * @param Node aNode
        */
       onArrowExpression: function(aNode) {
         // Infer the function's name from an enclosing syntax tree node.
         let inferredInfo = ParserHelpers.inferFunctionExpressionInfo(aNode);
         let inferredName = inferredInfo.name;
         let inferredChain = inferredInfo.chain;
         let inferredLocation = inferredInfo.loc;
         // Current node may be part of a larger assignment expression stack.
         if (aNode._parent.type == "AssignmentExpression") {
           this.onFunctionExpression(aNode._parent);
         }
         if (inferredName && inferredName.toLowerCase().contains(lowerCaseToken)) {
           store.push({
             inferredName: inferredName,
             inferredChain: inferredChain,
             inferredLocation: inferredLocation
           });
         }
       }
     });
     return store;
   },
   AST: null,
   url: "",
   length: 0,
   offset: 0
 };
 /**
  * Parser utility methods.
  */
 let ParserHelpers = {
   /**
    * Gets the location information for a node. Not all nodes have a
    * location property directly attached, or the location information
    * is incorrect, in which cases it's accessible via the parent.
    *
    * @param Node aNode
    *        The node who's location needs to be retrieved.
    * @return object
    *         An object containing { line, column } information.
    */
   getNodeLocation: function(aNode) {
     if (aNode.type != "Identifier") {
       return aNode.loc;
     }
     // Work around the fact that some identifier nodes don't have the
     // correct location attached.
     let { loc: parentLocation, type: parentType } = aNode._parent;
     let { loc: nodeLocation } = aNode;
     if (!nodeLocation) {
       if (parentType == "FunctionDeclaration" ||
           parentType == "FunctionExpression") {
         // e.g. "function foo() {}" or "{ bar: function foo() {} }"
         // The location is unavailable for the identifier node "foo".
         let loc = JSON.parse(JSON.stringify(parentLocation));
         loc.end.line = loc.start.line;
         loc.end.column = loc.start.column + aNode.name.length;
         return loc;
       }
       if (parentType == "MemberExpression") {
         // e.g. "foo.bar"
         // The location is unavailable for the identifier node "bar".
         let loc = JSON.parse(JSON.stringify(parentLocation));
         loc.start.line = loc.end.line;
         loc.start.column = loc.end.column - aNode.name.length;
         return loc;
       }
       if (parentType == "LabeledStatement") {
         // e.g. label: ...
         // The location is unavailable for the identifier node "label".
         let loc = JSON.parse(JSON.stringify(parentLocation));
         loc.end.line = loc.start.line;
         loc.end.column = loc.start.column + aNode.name.length;
         return loc;
       }
       if (parentType == "ContinueStatement") {
         // e.g. continue label
         // The location is unavailable for the identifier node "label".
         let loc = JSON.parse(JSON.stringify(parentLocation));
         loc.start.line = loc.end.line;
         loc.start.column = loc.end.column - aNode.name.length;
         return loc;
       }
     } else {
       if (parentType == "VariableDeclarator") {
         // e.g. "let foo = 42"
         // The location incorrectly spans across the whole variable declaration,
         // not just the identifier node "foo".
         let loc = JSON.parse(JSON.stringify(nodeLocation));
         loc.end.line = loc.start.line;
         loc.end.column = loc.start.column + aNode.name.length;
         return loc;
       }
     }
     return aNode.loc;
   },
   /**
    * Checks if a node's bounds contains a specified line.
    *
    * @param Node aNode
    *        The node's bounds used as reference.
    * @param number aLine
    *        The line number to check.
    * @return boolean
    *         True if the line and column is contained in the node's bounds.
    */
   nodeContainsLine: function(aNode, aLine) {
     let { start: s, end: e } = this.getNodeLocation(aNode);
     return s.line <= aLine && e.line >= aLine;
   },
   /**
    * Checks if a node's bounds contains a specified line and column.
    *
    * @param Node aNode
    *        The node's bounds used as reference.
    * @param number aLine
    *        The line number to check.
    * @param number aColumn
    *        The column number to check.
    * @return boolean
    *         True if the line and column is contained in the node's bounds.
    */
   nodeContainsPoint: function(aNode, aLine, aColumn) {
     let { start: s, end: e } = this.getNodeLocation(aNode);
     return s.line == aLine && e.line == aLine &&
            s.column <= aColumn && e.column >= aColumn;
   },
   /**
    * Try to infer a function expression's name & other details based on the
    * enclosing VariableDeclarator, AssignmentExpression or ObjectExpression.
    *
    * @param Node aNode
    *        The function expression node to get the name for.
    * @return object
    *         The inferred function name, or empty string can't infer the name,
    *         along with the chain (a generic "context", like a prototype chain)
    *         and location if available.
    */
   inferFunctionExpressionInfo: function(aNode) {
     let parent = aNode._parent;
     // A function expression may be defined in a variable declarator,
     // e.g. var foo = function(){}, in which case it is possible to infer
     // the variable name.
     if (parent.type == "VariableDeclarator") {
       return {
         name: parent.id.name,
         chain: null,
         loc: this.getNodeLocation(parent.id)
       };
     }
     // Function expressions can also be defined in assignment expressions,
     // e.g. foo = function(){} or foo.bar = function(){}, in which case it is
     // possible to infer the assignee name ("foo" and "bar" respectively).
     if (parent.type == "AssignmentExpression") {
       let propertyChain = this._getMemberExpressionPropertyChain(parent.left);
       let propertyLeaf = propertyChain.pop();
       return {
         name: propertyLeaf,
         chain: propertyChain,
         loc: this.getNodeLocation(parent.left)
       };
     }
     // If a function expression is defined in an object expression,
     // e.g. { foo: function(){} }, then it is possible to infer the name
     // from the corresponding property.
     if (parent.type == "ObjectExpression") {
       let propertyKey = this._getObjectExpressionPropertyKeyForValue(aNode);
       let propertyChain = this._getObjectExpressionPropertyChain(parent);
       let propertyLeaf = propertyKey.name;
       return {
         name: propertyLeaf,
         chain: propertyChain,
         loc: this.getNodeLocation(propertyKey)
       };
     }
     // Can't infer the function expression's name.
     return {
       name: "",
       chain: null,
       loc: null
     };
   },
   /**
    * Gets the name of an object expression's property to which a specified
    * value is assigned.
    *
    * Used for inferring function expression information and retrieving
    * an identifier evaluation string.
    *
    * For example, if aNode represents the "bar" identifier in a hypothetical
    * "{ foo: bar }" object expression, the returned node is the "foo" identifier.
    *
    * @param Node aNode
    *        The value node in an object expression.
    * @return object
    *         The key identifier node in the object expression.
    */
   _getObjectExpressionPropertyKeyForValue: function(aNode) {
     let parent = aNode._parent;
     if (parent.type != "ObjectExpression") {
       return null;
     }
     for (let property of parent.properties) {
       if (property.value == aNode) {
         return property.key;
       }
     }
   },
   /**
    * Gets an object expression's property chain to its parent
    * variable declarator or assignment expression, if available.
    *
    * Used for inferring function expression information and retrieving
    * an identifier evaluation string.
    *
    * For example, if aNode represents the "baz: {}" object expression in a
    * hypothetical "foo = { bar: { baz: {} } }" assignment expression, the
    * returned chain is ["foo", "bar", "baz"].
    *
    * @param Node aNode
    *        The object expression node to begin the scan from.
    * @param array aStore [optional]
    *        The chain to store the nodes into.
    * @return array
    *         The chain to the parent variable declarator, as strings.
    */
   _getObjectExpressionPropertyChain: function(aNode, aStore = []) {
     switch (aNode.type) {
       case "ObjectExpression":
         this._getObjectExpressionPropertyChain(aNode._parent, aStore);
         let propertyKey = this._getObjectExpressionPropertyKeyForValue(aNode);
         if (propertyKey) {
           aStore.push(propertyKey.name);
         }
         break;
       // Handle "var foo = { ... }" variable declarators.
       case "VariableDeclarator":
         aStore.push(aNode.id.name);
         break;
       // Handle "foo.bar = { ... }" assignment expressions, since they're
       // commonly used when defining an object's prototype methods; e.g:
       // "Foo.prototype = { ... }".
       case "AssignmentExpression":
         this._getMemberExpressionPropertyChain(aNode.left, aStore);
         break;
       // Additionally handle stuff like "foo = bar.baz({ ... })", because it's
       // commonly used in prototype-based inheritance in many libraries; e.g:
       // "Foo = Bar.extend({ ... })".
       case "NewExpression":
       case "CallExpression":
         this._getObjectExpressionPropertyChain(aNode._parent, aStore);
         break;
     }
     return aStore;
   },
   /**
    * Gets a member expression's property chain.
    *
    * Used for inferring function expression information and retrieving
    * an identifier evaluation string.
    *
    * For example, if aNode represents a hypothetical "foo.bar.baz"
    * member expression, the returned chain ["foo", "bar", "baz"].
    *
    * More complex expressions like foo.bar().baz are intentionally not handled.
    *
    * @param Node aNode
    *        The member expression node to begin the scan from.
    * @param array aStore [optional]
    *        The chain to store the nodes into.
    * @return array
    *         The full member chain, as strings.
    */
   _getMemberExpressionPropertyChain: function(aNode, aStore = []) {
     switch (aNode.type) {
       case "MemberExpression":
         this._getMemberExpressionPropertyChain(aNode.object, aStore);
         this._getMemberExpressionPropertyChain(aNode.property, aStore);
         break;
       case "ThisExpression":
         aStore.push("this");
         break;
       case "Identifier":
         aStore.push(aNode.name);
         break;
     }
     return aStore;
   },
   /**
    * Returns an evaluation string which can be used to obtain the
    * current value for the respective identifier.
    *
    * @param Node aNode
    *        The leaf node (e.g. Identifier, Literal) to begin the scan from.
    * @return string
    *         The corresponding evaluation string, or empty string if
    *         the specified leaf node can't be used.
    */
   getIdentifierEvalString: function(aNode) {
     switch (aNode._parent.type) {
       case "ObjectExpression":
         // If the identifier is the actual property value, it can be used
         // directly as an evaluation string. Otherwise, construct the property
         // access chain, since the value might have changed.
         if (!this._getObjectExpressionPropertyKeyForValue(aNode)) {
           let propertyChain = this._getObjectExpressionPropertyChain(aNode._parent);
           let propertyLeaf = aNode.name;
           return [...propertyChain, propertyLeaf].join(".");
         }
         break;
       case "MemberExpression":
         // Make sure this is a property identifier, not the parent object.
         if (aNode._parent.property == aNode) {
           return this._getMemberExpressionPropertyChain(aNode._parent).join(".");
         }
         break;
     }
     switch (aNode.type) {
       case "ThisExpression":
         return "this";
       case "Identifier":
         return aNode.name;
       case "Literal":
         return uneval(aNode.value);
       default:
         return "";
     }
   }
 };
 /**
  * A visitor for a syntax tree generated by the reflection API.
  * See https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API.
  *
  * All node types implement the following interface:
  * interface Node {
  *   type: string;
  *   loc: SourceLocation | null;
  * }
  */
 let SyntaxTreeVisitor = {
   /**
    * Walks a syntax tree.
    *
    * @param object aTree
    *        The AST nodes generated by the reflection API
    * @param object aCallbacks
    *        A map of all the callbacks to invoke when passing through certain
    *        types of noes (e.g: onFunctionDeclaration, onBlockStatement etc.).
    */
   walk: function(aTree, aCallbacks) {
     this.break = false;
     this[aTree.type](aTree, aCallbacks);
   },
   /**
    * Filters all the nodes in this syntax tree based on a predicate.
    *
    * @param object aTree
    *        The AST nodes generated by the reflection API
    * @param function aPredicate
    *        The predicate ran on each node.
    * @return array
    *         An array of nodes validating the predicate.
    */
   filter: function(aTree, aPredicate) {
     let store = [];
     this.walk(aTree, { onNode: e => { if (aPredicate(e)) store.push(e); } });
     return store;
   },
   /**
    * A flag checked on each node in the syntax tree. If true, walking is
    * abruptly halted.
    */
   break: false,
   /**
    * A complete program source tree.
    *
    * interface Program <: Node {
    *   type: "Program";
    *   body: [ Statement ];
    * }
    */
   Program: function(aNode, aCallbacks) {
     if (aCallbacks.onProgram) {
       aCallbacks.onProgram(aNode);
     }
     for (let statement of aNode.body) {
       this[statement.type](statement, aNode, aCallbacks);
     }
   },
   /**
    * Any statement.
    *
    * interface Statement <: Node { }
    */
   Statement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onStatement) {
       aCallbacks.onStatement(aNode);
     }
   },
   /**
    * An empty statement, i.e., a solitary semicolon.
    *
    * interface EmptyStatement <: Statement {
    *   type: "EmptyStatement";
    * }
    */
   EmptyStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onEmptyStatement) {
       aCallbacks.onEmptyStatement(aNode);
     }
   },
   /**
    * A block statement, i.e., a sequence of statements surrounded by braces.
    *
    * interface BlockStatement <: Statement {
    *   type: "BlockStatement";
    *   body: [ Statement ];
    * }
    */
   BlockStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onBlockStatement) {
       aCallbacks.onBlockStatement(aNode);
     }
     for (let statement of aNode.body) {
       this[statement.type](statement, aNode, aCallbacks);
     }
   },
   /**
    * An expression statement, i.e., a statement consisting of a single expression.
    *
    * interface ExpressionStatement <: Statement {
    *   type: "ExpressionStatement";
    *   expression: Expression;
    * }
    */
   ExpressionStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onExpressionStatement) {
       aCallbacks.onExpressionStatement(aNode);
     }
     this[aNode.expression.type](aNode.expression, aNode, aCallbacks);
   },
   /**
    * An if statement.
    *
    * interface IfStatement <: Statement {
    *   type: "IfStatement";
    *   test: Expression;
    *   consequent: Statement;
    *   alternate: Statement | null;
    * }
    */
   IfStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onIfStatement) {
       aCallbacks.onIfStatement(aNode);
     }
     this[aNode.test.type](aNode.test, aNode, aCallbacks);
     this[aNode.consequent.type](aNode.consequent, aNode, aCallbacks);
     if (aNode.alternate) {
       this[aNode.alternate.type](aNode.alternate, aNode, aCallbacks);
     }
   },
   /**
    * A labeled statement, i.e., a statement prefixed by a break/continue label.
    *
    * interface LabeledStatement <: Statement {
    *   type: "LabeledStatement";
    *   label: Identifier;
    *   body: Statement;
    * }
    */
   LabeledStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onLabeledStatement) {
       aCallbacks.onLabeledStatement(aNode);
     }
     this[aNode.label.type](aNode.label, aNode, aCallbacks);
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * A break statement.
    *
    * interface BreakStatement <: Statement {
    *   type: "BreakStatement";
    *   label: Identifier | null;
    * }
    */
   BreakStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onBreakStatement) {
       aCallbacks.onBreakStatement(aNode);
     }
     if (aNode.label) {
       this[aNode.label.type](aNode.label, aNode, aCallbacks);
     }
   },
   /**
    * A continue statement.
    *
    * interface ContinueStatement <: Statement {
    *   type: "ContinueStatement";
    *   label: Identifier | null;
    * }
    */
   ContinueStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onContinueStatement) {
       aCallbacks.onContinueStatement(aNode);
     }
     if (aNode.label) {
       this[aNode.label.type](aNode.label, aNode, aCallbacks);
     }
   },
   /**
    * A with statement.
    *
    * interface WithStatement <: Statement {
    *   type: "WithStatement";
    *   object: Expression;
    *   body: Statement;
    * }
    */
   WithStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onWithStatement) {
       aCallbacks.onWithStatement(aNode);
     }
     this[aNode.object.type](aNode.object, aNode, aCallbacks);
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * A switch statement. The lexical flag is metadata indicating whether the
    * switch statement contains any unnested let declarations (and therefore
    * introduces a new lexical scope).
    *
    * interface SwitchStatement <: Statement {
    *   type: "SwitchStatement";
    *   discriminant: Expression;
    *   cases: [ SwitchCase ];
    *   lexical: boolean;
    * }
    */
   SwitchStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onSwitchStatement) {
       aCallbacks.onSwitchStatement(aNode);
     }
     this[aNode.discriminant.type](aNode.discriminant, aNode, aCallbacks);
     for (let _case of aNode.cases) {
       this[_case.type](_case, aNode, aCallbacks);
     }
   },
   /**
    * A return statement.
    *
    * interface ReturnStatement <: Statement {
    *   type: "ReturnStatement";
    *   argument: Expression | null;
    * }
    */
   ReturnStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onReturnStatement) {
       aCallbacks.onReturnStatement(aNode);
     }
     if (aNode.argument) {
       this[aNode.argument.type](aNode.argument, aNode, aCallbacks);
     }
   },
   /**
    * A throw statement.
    *
    * interface ThrowStatement <: Statement {
    *   type: "ThrowStatement";
    *   argument: Expression;
    * }
    */
   ThrowStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onThrowStatement) {
       aCallbacks.onThrowStatement(aNode);
     }
     this[aNode.argument.type](aNode.argument, aNode, aCallbacks);
   },
   /**
    * A try statement.
    *
    * interface TryStatement <: Statement {
    *   type: "TryStatement";
    *   block: BlockStatement;
    *   handler: CatchClause | null;
    *   guardedHandlers: [ CatchClause ];
    *   finalizer: BlockStatement | null;
    * }
    */
   TryStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onTryStatement) {
       aCallbacks.onTryStatement(aNode);
     }
     this[aNode.block.type](aNode.block, aNode, aCallbacks);
     if (aNode.handler) {
       this[aNode.handler.type](aNode.handler, aNode, aCallbacks);
     }
     for (let guardedHandler of aNode.guardedHandlers) {
       this[guardedHandler.type](guardedHandler, aNode, aCallbacks);
     }
     if (aNode.finalizer) {
       this[aNode.finalizer.type](aNode.finalizer, aNode, aCallbacks);
     }
   },
   /**
    * A while statement.
    *
    * interface WhileStatement <: Statement {
    *   type: "WhileStatement";
    *   test: Expression;
    *   body: Statement;
    * }
    */
   WhileStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onWhileStatement) {
       aCallbacks.onWhileStatement(aNode);
     }
     this[aNode.test.type](aNode.test, aNode, aCallbacks);
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * A do/while statement.
    *
    * interface DoWhileStatement <: Statement {
    *   type: "DoWhileStatement";
    *   body: Statement;
    *   test: Expression;
    * }
    */
   DoWhileStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onDoWhileStatement) {
       aCallbacks.onDoWhileStatement(aNode);
     }
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
     this[aNode.test.type](aNode.test, aNode, aCallbacks);
   },
   /**
    * A for statement.
    *
    * interface ForStatement <: Statement {
    *   type: "ForStatement";
    *   init: VariableDeclaration | Expression | null;
    *   test: Expression | null;
    *   update: Expression | null;
    *   body: Statement;
    * }
    */
   ForStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onForStatement) {
       aCallbacks.onForStatement(aNode);
     }
     if (aNode.init) {
       this[aNode.init.type](aNode.init, aNode, aCallbacks);
     }
     if (aNode.test) {
       this[aNode.test.type](aNode.test, aNode, aCallbacks);
     }
     if (aNode.update) {
       this[aNode.update.type](aNode.update, aNode, aCallbacks);
     }
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * A for/in statement, or, if each is true, a for each/in statement.
    *
    * interface ForInStatement <: Statement {
    *   type: "ForInStatement";
    *   left: VariableDeclaration | Expression;
    *   right: Expression;
    *   body: Statement;
    *   each: boolean;
    * }
    */
   ForInStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onForInStatement) {
       aCallbacks.onForInStatement(aNode);
     }
     this[aNode.left.type](aNode.left, aNode, aCallbacks);
     this[aNode.right.type](aNode.right, aNode, aCallbacks);
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * A for/of statement.
    *
    * interface ForOfStatement <: Statement {
    *   type: "ForOfStatement";
    *   left: VariableDeclaration | Expression;
    *   right: Expression;
    *   body: Statement;
    * }
    */
   ForOfStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onForOfStatement) {
       aCallbacks.onForOfStatement(aNode);
     }
     this[aNode.left.type](aNode.left, aNode, aCallbacks);
     this[aNode.right.type](aNode.right, aNode, aCallbacks);
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * A let statement.
    *
    * interface LetStatement <: Statement {
    *   type: "LetStatement";
    *   head: [ { id: Pattern, init: Expression | null } ];
    *   body: Statement;
    * }
    */
   LetStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onLetStatement) {
       aCallbacks.onLetStatement(aNode);
     }
     for (let { id, init } of aNode.head) {
       this[id.type](id, aNode, aCallbacks);
       if (init) {
         this[init.type](init, aNode, aCallbacks);
       }
     }
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * A debugger statement.
    *
    * interface DebuggerStatement <: Statement {
    *   type: "DebuggerStatement";
    * }
    */
   DebuggerStatement: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onDebuggerStatement) {
       aCallbacks.onDebuggerStatement(aNode);
     }
   },
   /**
    * Any declaration node. Note that declarations are considered statements;
    * this is because declarations can appear in any statement context in the
    * language recognized by the SpiderMonkey parser.
    *
    * interface Declaration <: Statement { }
    */
   Declaration: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onDeclaration) {
       aCallbacks.onDeclaration(aNode);
     }
   },
   /**
    * A function declaration.
    *
    * interface FunctionDeclaration <: Function, Declaration {
    *   type: "FunctionDeclaration";
    *   id: Identifier;
    *   params: [ Pattern ];
    *   defaults: [ Expression ];
    *   rest: Identifier | null;
    *   body: BlockStatement | Expression;
    *   generator: boolean;
    *   expression: boolean;
    * }
    */
   FunctionDeclaration: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onFunctionDeclaration) {
       aCallbacks.onFunctionDeclaration(aNode);
     }
     this[aNode.id.type](aNode.id, aNode, aCallbacks);
     for (let param of aNode.params) {
       this[param.type](param, aNode, aCallbacks);
     }
     for (let _default of aNode.defaults) {
       this[_default.type](_default, aNode, aCallbacks);
     }
     if (aNode.rest) {
       this[aNode.rest.type](aNode.rest, aNode, aCallbacks);
     }
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * A variable declaration, via one of var, let, or const.
    *
    * interface VariableDeclaration <: Declaration {
    *   type: "VariableDeclaration";
    *   declarations: [ VariableDeclarator ];
    *   kind: "var" | "let" | "const";
    * }
    */
   VariableDeclaration: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onVariableDeclaration) {
       aCallbacks.onVariableDeclaration(aNode);
     }
     for (let declaration of aNode.declarations) {
       this[declaration.type](declaration, aNode, aCallbacks);
     }
   },
   /**
    * A variable declarator.
    *
    * interface VariableDeclarator <: Node {
    *   type: "VariableDeclarator";
    *   id: Pattern;
    *   init: Expression | null;
    * }
    */
   VariableDeclarator: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onVariableDeclarator) {
       aCallbacks.onVariableDeclarator(aNode);
     }
     this[aNode.id.type](aNode.id, aNode, aCallbacks);
     if (aNode.init) {
       this[aNode.init.type](aNode.init, aNode, aCallbacks);
     }
   },
   /**
    * Any expression node. Since the left-hand side of an assignment may be any
    * expression in general, an expression can also be a pattern.
    *
    * interface Expression <: Node, Pattern { }
    */
   Expression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onExpression) {
       aCallbacks.onExpression(aNode);
     }
   },
   /**
    * A this expression.
    *
    * interface ThisExpression <: Expression {
    *   type: "ThisExpression";
    * }
    */
   ThisExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onThisExpression) {
       aCallbacks.onThisExpression(aNode);
     }
   },
   /**
    * An array expression.
    *
    * interface ArrayExpression <: Expression {
    *   type: "ArrayExpression";
    *   elements: [ Expression | null ];
    * }
    */
   ArrayExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onArrayExpression) {
       aCallbacks.onArrayExpression(aNode);
     }
     for (let element of aNode.elements) {
       // TODO: remove the typeof check when support for SpreadExpression is
       // added (bug 890913).
       if (element && typeof this[element.type] == "function") {
         this[element.type](element, aNode, aCallbacks);
       }
     }
   },
   /**
    * An object expression. A literal property in an object expression can have
    * either a string or number as its value. Ordinary property initializers
    * have a kind value "init"; getters and setters have the kind values "get"
    * and "set", respectively.
    *
    * interface ObjectExpression <: Expression {
    *   type: "ObjectExpression";
    *   properties: [ { key: Literal | Identifier,
    *                   value: Expression,
    *                   kind: "init" | "get" | "set" } ];
    * }
    */
   ObjectExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onObjectExpression) {
       aCallbacks.onObjectExpression(aNode);
     }
     for (let { key, value } of aNode.properties) {
       this[key.type](key, aNode, aCallbacks);
       this[value.type](value, aNode, aCallbacks);
     }
   },
   /**
    * A function expression.
    *
    * interface FunctionExpression <: Function, Expression {
    *   type: "FunctionExpression";
    *   id: Identifier | null;
    *   params: [ Pattern ];
    *   defaults: [ Expression ];
    *   rest: Identifier | null;
    *   body: BlockStatement | Expression;
    *   generator: boolean;
    *   expression: boolean;
    * }
    */
   FunctionExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onFunctionExpression) {
       aCallbacks.onFunctionExpression(aNode);
     }
     if (aNode.id) {
       this[aNode.id.type](aNode.id, aNode, aCallbacks);
     }
     for (let param of aNode.params) {
       this[param.type](param, aNode, aCallbacks);
     }
     for (let _default of aNode.defaults) {
       this[_default.type](_default, aNode, aCallbacks);
     }
     if (aNode.rest) {
       this[aNode.rest.type](aNode.rest, aNode, aCallbacks);
     }
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * An arrow expression.
    *
    * interface ArrowExpression <: Function, Expression {
    *   type: "ArrowExpression";
    *   params: [ Pattern ];
    *   defaults: [ Expression ];
    *   rest: Identifier | null;
    *   body: BlockStatement | Expression;
    *   generator: boolean;
    *   expression: boolean;
    * }
    */
   ArrowExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onArrowExpression) {
       aCallbacks.onArrowExpression(aNode);
     }
     for (let param of aNode.params) {
       this[param.type](param, aNode, aCallbacks);
     }
     for (let _default of aNode.defaults) {
       this[_default.type](_default, aNode, aCallbacks);
     }
     if (aNode.rest) {
       this[aNode.rest.type](aNode.rest, aNode, aCallbacks);
     }
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * A sequence expression, i.e., a comma-separated sequence of expressions.
    *
    * interface SequenceExpression <: Expression {
    *   type: "SequenceExpression";
    *   expressions: [ Expression ];
    * }
    */
   SequenceExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onSequenceExpression) {
       aCallbacks.onSequenceExpression(aNode);
     }
     for (let expression of aNode.expressions) {
       this[expression.type](expression, aNode, aCallbacks);
     }
   },
   /**
    * A unary operator expression.
    *
    * interface UnaryExpression <: Expression {
    *   type: "UnaryExpression";
    *   operator: UnaryOperator;
    *   prefix: boolean;
    *   argument: Expression;
    * }
    */
   UnaryExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onUnaryExpression) {
       aCallbacks.onUnaryExpression(aNode);
     }
     this[aNode.argument.type](aNode.argument, aNode, aCallbacks);
   },
   /**
    * A binary operator expression.
    *
    * interface BinaryExpression <: Expression {
    *   type: "BinaryExpression";
    *   operator: BinaryOperator;
    *   left: Expression;
    *   right: Expression;
    * }
    */
   BinaryExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onBinaryExpression) {
       aCallbacks.onBinaryExpression(aNode);
     }
     this[aNode.left.type](aNode.left, aNode, aCallbacks);
     this[aNode.right.type](aNode.right, aNode, aCallbacks);
   },
   /**
    * An assignment operator expression.
    *
    * interface AssignmentExpression <: Expression {
    *   type: "AssignmentExpression";
    *   operator: AssignmentOperator;
    *   left: Expression;
    *   right: Expression;
    * }
    */
   AssignmentExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onAssignmentExpression) {
       aCallbacks.onAssignmentExpression(aNode);
     }
     this[aNode.left.type](aNode.left, aNode, aCallbacks);
     this[aNode.right.type](aNode.right, aNode, aCallbacks);
   },
   /**
    * An update (increment or decrement) operator expression.
    *
    * interface UpdateExpression <: Expression {
    *   type: "UpdateExpression";
    *   operator: UpdateOperator;
    *   argument: Expression;
    *   prefix: boolean;
    * }
    */
   UpdateExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onUpdateExpression) {
       aCallbacks.onUpdateExpression(aNode);
     }
     this[aNode.argument.type](aNode.argument, aNode, aCallbacks);
   },
   /**
    * A logical operator expression.
    *
    * interface LogicalExpression <: Expression {
    *   type: "LogicalExpression";
    *   operator: LogicalOperator;
    *   left: Expression;
    *   right: Expression;
    * }
    */
   LogicalExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onLogicalExpression) {
       aCallbacks.onLogicalExpression(aNode);
     }
     this[aNode.left.type](aNode.left, aNode, aCallbacks);
     this[aNode.right.type](aNode.right, aNode, aCallbacks);
   },
   /**
    * A conditional expression, i.e., a ternary ?/: expression.
    *
    * interface ConditionalExpression <: Expression {
    *   type: "ConditionalExpression";
    *   test: Expression;
    *   alternate: Expression;
    *   consequent: Expression;
    * }
    */
   ConditionalExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onConditionalExpression) {
       aCallbacks.onConditionalExpression(aNode);
     }
     this[aNode.test.type](aNode.test, aNode, aCallbacks);
     this[aNode.alternate.type](aNode.alternate, aNode, aCallbacks);
     this[aNode.consequent.type](aNode.consequent, aNode, aCallbacks);
   },
   /**
    * A new expression.
    *
    * interface NewExpression <: Expression {
    *   type: "NewExpression";
    *   callee: Expression;
    *   arguments: [ Expression | null ];
    * }
    */
   NewExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onNewExpression) {
       aCallbacks.onNewExpression(aNode);
     }
     this[aNode.callee.type](aNode.callee, aNode, aCallbacks);
     for (let argument of aNode.arguments) {
       if (argument) {
         this[argument.type](argument, aNode, aCallbacks);
       }
     }
   },
   /**
    * A function or method call expression.
    *
    * interface CallExpression <: Expression {
    *   type: "CallExpression";
    *   callee: Expression;
    *   arguments: [ Expression | null ];
    * }
    */
   CallExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onCallExpression) {
       aCallbacks.onCallExpression(aNode);
     }
     this[aNode.callee.type](aNode.callee, aNode, aCallbacks);
     for (let argument of aNode.arguments) {
       if (argument) {
         this[argument.type](argument, aNode, aCallbacks);
       }
     }
   },
   /**
    * A member expression. If computed is true, the node corresponds to a
    * computed e1[e2] expression and property is an Expression. If computed is
    * false, the node corresponds to a static e1.x expression and property is an
    * Identifier.
    *
    * interface MemberExpression <: Expression {
    *   type: "MemberExpression";
    *   object: Expression;
    *   property: Identifier | Expression;
    *   computed: boolean;
    * }
    */
   MemberExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onMemberExpression) {
       aCallbacks.onMemberExpression(aNode);
     }
     this[aNode.object.type](aNode.object, aNode, aCallbacks);
     this[aNode.property.type](aNode.property, aNode, aCallbacks);
   },
   /**
    * A yield expression.
    *
    * interface YieldExpression <: Expression {
    *   argument: Expression | null;
    * }
    */
   YieldExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onYieldExpression) {
       aCallbacks.onYieldExpression(aNode);
     }
     if (aNode.argument) {
       this[aNode.argument.type](aNode.argument, aNode, aCallbacks);
     }
   },
   /**
    * An array comprehension. The blocks array corresponds to the sequence of
    * for and for each blocks. The optional filter expression corresponds to the
    * final if clause, if present.
    *
    * interface ComprehensionExpression <: Expression {
    *   body: Expression;
    *   blocks: [ ComprehensionBlock ];
    *   filter: Expression | null;
    * }
    */
   ComprehensionExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onComprehensionExpression) {
       aCallbacks.onComprehensionExpression(aNode);
     }
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
     for (let block of aNode.blocks) {
       this[block.type](block, aNode, aCallbacks);
     }
     if (aNode.filter) {
       this[aNode.filter.type](aNode.filter, aNode, aCallbacks);
     }
   },
   /**
    * A generator expression. As with array comprehensions, the blocks array
    * corresponds to the sequence of for and for each blocks, and the optional
    * filter expression corresponds to the final if clause, if present.
    *
    * interface GeneratorExpression <: Expression {
    *   body: Expression;
    *   blocks: [ ComprehensionBlock ];
    *   filter: Expression | null;
    * }
    */
   GeneratorExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onGeneratorExpression) {
       aCallbacks.onGeneratorExpression(aNode);
     }
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
     for (let block of aNode.blocks) {
       this[block.type](block, aNode, aCallbacks);
     }
     if (aNode.filter) {
       this[aNode.filter.type](aNode.filter, aNode, aCallbacks);
     }
   },
   /**
    * A graph expression, aka "sharp literal," such as #1={ self: #1# }.
    *
    * interface GraphExpression <: Expression {
    *   index: uint32;
    *   expression: Literal;
    * }
    */
   GraphExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onGraphExpression) {
       aCallbacks.onGraphExpression(aNode);
     }
     this[aNode.expression.type](aNode.expression, aNode, aCallbacks);
   },
   /**
    * A graph index expression, aka "sharp variable," such as #1#.
    *
    * interface GraphIndexExpression <: Expression {
    *   index: uint32;
    * }
    */
   GraphIndexExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onGraphIndexExpression) {
       aCallbacks.onGraphIndexExpression(aNode);
     }
   },
   /**
    * A let expression.
    *
    * interface LetExpression <: Expression {
    *   type: "LetExpression";
    *   head: [ { id: Pattern, init: Expression | null } ];
    *   body: Expression;
    * }
    */
   LetExpression: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onLetExpression) {
       aCallbacks.onLetExpression(aNode);
     }
     for (let { id, init } of aNode.head) {
       this[id.type](id, aNode, aCallbacks);
       if (init) {
         this[init.type](init, aNode, aCallbacks);
       }
     }
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * Any pattern.
    *
    * interface Pattern <: Node { }
    */
   Pattern: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onPattern) {
       aCallbacks.onPattern(aNode);
     }
   },
   /**
    * An object-destructuring pattern. A literal property in an object pattern
    * can have either a string or number as its value.
    *
    * interface ObjectPattern <: Pattern {
    *   type: "ObjectPattern";
    *   properties: [ { key: Literal | Identifier, value: Pattern } ];
    * }
    */
   ObjectPattern: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onObjectPattern) {
       aCallbacks.onObjectPattern(aNode);
     }
     for (let { key, value } of aNode.properties) {
       this[key.type](key, aNode, aCallbacks);
       this[value.type](value, aNode, aCallbacks);
     }
   },
   /**
    * An array-destructuring pattern.
    *
    * interface ArrayPattern <: Pattern {
    *   type: "ArrayPattern";
    *   elements: [ Pattern | null ];
    * }
    */
   ArrayPattern: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onArrayPattern) {
       aCallbacks.onArrayPattern(aNode);
     }
     for (let element of aNode.elements) {
       if (element) {
         this[element.type](element, aNode, aCallbacks);
       }
     }
   },
   /**
    * A case (if test is an Expression) or default (if test is null) clause in
    * the body of a switch statement.
    *
    * interface SwitchCase <: Node {
    *   type: "SwitchCase";
    *   test: Expression | null;
    *   consequent: [ Statement ];
    * }
    */
   SwitchCase: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onSwitchCase) {
       aCallbacks.onSwitchCase(aNode);
     }
     if (aNode.test) {
       this[aNode.test.type](aNode.test, aNode, aCallbacks);
     }
     for (let consequent of aNode.consequent) {
       this[consequent.type](consequent, aNode, aCallbacks);
     }
   },
   /**
    * A catch clause following a try block. The optional guard property
    * corresponds to the optional expression guard on the bound variable.
    *
    * interface CatchClause <: Node {
    *   type: "CatchClause";
    *   param: Pattern;
    *   guard: Expression | null;
    *   body: BlockStatement;
    * }
    */
   CatchClause: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onCatchClause) {
       aCallbacks.onCatchClause(aNode);
     }
     this[aNode.param.type](aNode.param, aNode, aCallbacks);
     if (aNode.guard) {
       this[aNode.guard.type](aNode.guard, aNode, aCallbacks);
     }
     this[aNode.body.type](aNode.body, aNode, aCallbacks);
   },
   /**
    * A for or for each block in an array comprehension or generator expression.
    *
    * interface ComprehensionBlock <: Node {
    *   left: Pattern;
    *   right: Expression;
    *   each: boolean;
    * }
    */
   ComprehensionBlock: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onComprehensionBlock) {
       aCallbacks.onComprehensionBlock(aNode);
     }
     this[aNode.left.type](aNode.left, aNode, aCallbacks);
     this[aNode.right.type](aNode.right, aNode, aCallbacks);
   },
   /**
    * An identifier. Note that an identifier may be an expression or a
    * destructuring pattern.
    *
    * interface Identifier <: Node, Expression, Pattern {
    *   type: "Identifier";
    *   name: string;
    * }
    */
   Identifier: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onIdentifier) {
       aCallbacks.onIdentifier(aNode);
     }
   },
   /**
    * A literal token. Note that a literal can be an expression.
    *
    * interface Literal <: Node, Expression {
    *   type: "Literal";
    *   value: string | boolean | null | number | RegExp;
    * }
    */
   Literal: function(aNode, aParent, aCallbacks) {
     aNode._parent = aParent;
     if (this.break) {
       return;
     }
     if (aCallbacks.onNode) {
       if (aCallbacks.onNode(aNode, aParent) === false) {
         return;
       }
     }
     if (aCallbacks.onLiteral) {
       aCallbacks.onLiteral(aNode);
     }
   }
 };
 XPCOMUtils.defineLazyGetter(Parser, "reflectionAPI", () => Reflect);

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browser/devtools/shared/Parser.jsm@6474c204b198 (annotated)

browser/devtools/shared/Parser.jsm