text: // AST walker module for Mozilla Parser API compatible trees
  
  (function(exports) {
    "use strict";
  
    // A simple walk is one where you simply specify callbacks to be
    // called on specific nodes. The last two arguments are optional. A
    // simple use would be
    //
    //     walk.simple(myTree, {
    //         Expression: function(node) { ... }
    //     });
    //
    // to do something with all expressions. All Parser API node types
    // can be used to identify node types, as well as Expression,
    // Statement, and ScopeBody, which denote categories of nodes.
    //
    // The base argument can be used to pass a custom (recursive)
    // walker, and state can be used to give this walked an initial
    // state.
    exports.simple = function(node, visitors, base, state) {
      if (!base) base = exports;
      function c(node, st, override) {
        var type = override || node.type, found = visitors[type];
        base[type](node, st, c);
        if (found) found(node, st);
      }
      c(node, state);
    };
  
    // A recursive walk is one where your functions override the default
    // walkers. They can modify and replace the state parameter that's
    // threaded through the walk, and can opt how and whether to walk
    // their child nodes (by calling their third argument on these
    // nodes).
    exports.recursive = function(node, state, funcs, base) {
      var visitor = funcs ? exports.make(funcs, base) : base;
      function c(node, st, override) {
        visitor[override || node.type](node, st, c);
      }
      c(node, state);
    };
  
    // Used to create a custom walker. Will fill in all missing node
    // type properties with the defaults.
    exports.make = function(funcs, base) {
      if (!base) base = exports;
      var visitor = {};
      for (var type in base) visitor[type] = base[type];
      for (var type in funcs) visitor[type] = funcs[type];
      return visitor;
    };
  
    function skipThrough(node, st, c) { c(node, st); }
    function ignore(node, st, c) {}
  
    // Node walkers.
  
    exports.Program = exports.BlockStatement = function(node, st, c) {
      for (var i = 0; i < node.body.length; ++i)
        c(node.body[i], st, "Statement");
    };
    exports.Statement = skipThrough;
    exports.EmptyStatement = ignore;
    exports.ExpressionStatement = function(node, st, c) {
      c(node.expression, st, "Expression");
    };
    exports.IfStatement = function(node, st, c) {
      c(node.test, st, "Expression");
      c(node.consequent, st, "Statement");
      if (node.alternate) c(node.alternate, st, "Statement");
    };
    exports.LabeledStatement = function(node, st, c) {
      c(node.body, st, "Statement");
    };
    exports.BreakStatement = exports.ContinueStatement = ignore;
    exports.WithStatement = function(node, st, c) {
      c(node.object, st, "Expression");
      c(node.body, st, "Statement");
    };
    exports.SwitchStatement = function(node, st, c) {
      c(node.discriminant, st, "Expression");
      for (var i = 0; i < node.cases.length; ++i) {
        var cs = node.cases[i];
        if (cs.test) c(cs.test, st, "Expression");
        for (var j = 0; j < cs.consequent.length; ++j)
          c(cs.consequent[j], st, "Statement");
      }
    };
    exports.ReturnStatement = function(node, st, c) {
      if (node.argument) c(node.argument, st, "Expression");
    };
    exports.ThrowStatement = function(node, st, c) {
      c(node.argument, st, "Expression");
    };
    exports.TryStatement = function(node, st, c) {
      c(node.block, st, "Statement");
      for (var i = 0; i < node.handlers.length; ++i)
        c(node.handlers[i].body, st, "ScopeBody");
      if (node.finalizer) c(node.finalizer, st, "Statement");
    };
    exports.WhileStatement = function(node, st, c) {
      c(node.test, st, "Expression");
      c(node.body, st, "Statement");
    };
    exports.DoWhileStatement = exports.WhileStatement;
    exports.ForStatement = function(node, st, c) {
      if (node.init) c(node.init, st, "ForInit");
      if (node.test) c(node.test, st, "Expression");
      if (node.update) c(node.update, st, "Expression");
      c(node.body, st, "Statement");
    };
    exports.ForInStatement = function(node, st, c) {
      c(node.left, st, "ForInit");
      c(node.right, st, "Expression");
      c(node.body, st, "Statement");
    };
    exports.ForInit = function(node, st, c) {
      if (node.type == "VariableDeclaration") c(node, st);
      else c(node, st, "Expression");
    };
    exports.DebuggerStatement = ignore;
  
    exports.FunctionDeclaration = function(node, st, c) {
      c(node, st, "Function");
    };
    exports.VariableDeclaration = function(node, st, c) {
      for (var i = 0; i < node.declarations.length; ++i) {
        var decl = node.declarations[i];
        if (decl.init) c(decl.init, st, "Expression");
      }
    };
  
    exports.Function = function(node, st, c) {
      c(node.body, st, "ScopeBody");
    };
    exports.ScopeBody = function(node, st, c) {
      c(node, st, "Statement");
    };
  
    exports.Expression = skipThrough;
    exports.ThisExpression = ignore;
    exports.ArrayExpression = function(node, st, c) {
      for (var i = 0; i < node.elements.length; ++i) {
        var elt = node.elements[i];
        if (elt) c(elt, st, "Expression");
      }
    };
    exports.ObjectExpression = function(node, st, c) {
      for (var i = 0; i < node.properties.length; ++i)
        c(node.properties[i].value, st, "Expression");
    };
    exports.FunctionExpression = exports.FunctionDeclaration;
    exports.SequenceExpression = function(node, st, c) {
      for (var i = 0; i < node.expressions.length; ++i)
        c(node.expressions[i], st, "Expression");
    };
    exports.UnaryExpression = exports.UpdateExpression = function(node, st, c) {
      c(node.argument, st, "Expression");
    };
    exports.BinaryExpression = exports.AssignmentExpression = exports.LogicalExpression = function(node, st, c) {
      c(node.left, st, "Expression");
      c(node.right, st, "Expression");
    };
    exports.ConditionalExpression = function(node, st, c) {
      c(node.test, st, "Expression");
      c(node.consequent, st, "Expression");
      c(node.alternate, st, "Expression");
    };
    exports.NewExpression = exports.CallExpression = function(node, st, c) {
      c(node.callee, st, "Expression");
      if (node.arguments) for (var i = 0; i < node.arguments.length; ++i)
        c(node.arguments[i], st, "Expression");
    };
    exports.MemberExpression = function(node, st, c) {
      c(node.object, st, "Expression");
      if (node.computed) c(node.property, st, "Expression");
    };
    exports.Identifier = exports.Literal = ignore;
  
    // A custom walker that keeps track of the scope chain and the
    // variables defined in it.
    function makeScope(prev) {
      return {vars: Object.create(null), prev: prev};
    }
    exports.scopeVisitor = exports.make({
      Function: function(node, scope, c) {
        var inner = makeScope(scope);
        for (var i = 0; i < node.params.length; ++i)
          inner.vars[node.params[i].name] = {type: "argument", node: node.params[i]};
        if (node.id) {
          var decl = node.type == "FunctionDeclaration";
          (decl ? scope : inner).vars[node.id.name] =
            {type: decl ? "function" : "function name", node: node.id};
        }
        c(node.body, inner, "ScopeBody");
      },
      TryStatement: function(node, scope, c) {
        c(node.block, scope, "Statement");
        for (var i = 0; i < node.handlers.length; ++i) {
          var handler = node.handlers[i], inner = makeScope(scope);
          inner.vars[handler.param.name] = {type: "catch clause", node: handler.param};
          c(handler.body, inner, "ScopeBody");
        }
        if (node.finalizer) c(node.finalizer, scope, "Statement");
      },
      VariableDeclaration: function(node, scope, c) {
        for (var i = 0; i < node.declarations.length; ++i) {
          var decl = node.declarations[i];
          scope.vars[decl.id.name] = {type: "var", node: decl.id};
          if (decl.init) c(decl.init, scope, "Expression");
        }
      }
    });
  
  })(typeof exports == "undefined" ? acorn.walk = {} : exports);
  