node_modules

8 files changed, 2069 insertions, 0 deletions

diff --git a/node_modules/escope/src/definition.js b/node_modules/escope/src/definition.js
new file mode 100644
index 000000000..faef9387c
--- /dev/null
+++ b/node_modules/escope/src/definition.js
@@ -0,0 +1,78 @@
+/*
+  Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+import Variable from './variable';
+
+/**
+ * @class Definition
+ */
+export default class Definition {
+    constructor(type, name, node, parent, index, kind) {
+        /**
+         * @member {String} Definition#type - type of the occurrence (e.g. "Parameter", "Variable", ...).
+         */
+        this.type = type;
+        /**
+         * @member {esprima.Identifier} Definition#name - the identifier AST node of the occurrence.
+         */
+        this.name = name;
+        /**
+         * @member {esprima.Node} Definition#node - the enclosing node of the identifier.
+         */
+        this.node = node;
+        /**
+         * @member {esprima.Node?} Definition#parent - the enclosing statement node of the identifier.
+         */
+        this.parent = parent;
+        /**
+         * @member {Number?} Definition#index - the index in the declaration statement.
+         */
+        this.index = index;
+        /**
+         * @member {String?} Definition#kind - the kind of the declaration statement.
+         */
+        this.kind = kind;
+    }
+}
+
+/**
+ * @class ParameterDefinition
+ */
+class ParameterDefinition extends Definition {
+    constructor(name, node, index, rest) {
+        super(Variable.Parameter, name, node, null, index, null);
+        /**
+         * Whether the parameter definition is a part of a rest parameter.
+         * @member {boolean} ParameterDefinition#rest
+         */
+        this.rest = rest;
+    }
+}
+
+export {
+    ParameterDefinition,
+    Definition
+}
+
+/* vim: set sw=4 ts=4 et tw=80 : */
diff --git a/node_modules/escope/src/index.js b/node_modules/escope/src/index.js
new file mode 100644
index 000000000..a345e1c71
--- /dev/null
+++ b/node_modules/escope/src/index.js
@@ -0,0 +1,146 @@
+/*
+  Copyright (C) 2012-2014 Yusuke Suzuki <utatane.tea@gmail.com>
+  Copyright (C) 2013 Alex Seville <hi@alexanderseville.com>
+  Copyright (C) 2014 Thiago de Arruda <tpadilha84@gmail.com>
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/**
+ * Escope (<a href="http://github.com/estools/escope">escope</a>) is an <a
+ * href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">ECMAScript</a>
+ * scope analyzer extracted from the <a
+ * href="http://github.com/estools/esmangle">esmangle project</a/>.
+ * <p>
+ * <em>escope</em> finds lexical scopes in a source program, i.e. areas of that
+ * program where different occurrences of the same identifier refer to the same
+ * variable. With each scope the contained variables are collected, and each
+ * identifier reference in code is linked to its corresponding variable (if
+ * possible).
+ * <p>
+ * <em>escope</em> works on a syntax tree of the parsed source code which has
+ * to adhere to the <a
+ * href="https://developer.mozilla.org/en-US/docs/SpiderMonkey/Parser_API">
+ * Mozilla Parser API</a>. E.g. <a href="http://esprima.org">esprima</a> is a parser
+ * that produces such syntax trees.
+ * <p>
+ * The main interface is the {@link analyze} function.
+ * @module escope
+ */
+
+/*jslint bitwise:true */
+
+import assert from 'assert';
+
+import ScopeManager from './scope-manager';
+import Referencer from './referencer';
+import Reference from './reference';
+import Variable from './variable';
+import Scope from './scope';
+import { version } from '../package.json';
+
+function defaultOptions() {
+    return {
+        optimistic: false,
+        directive: false,
+        nodejsScope: false,
+        impliedStrict: false,
+        sourceType: 'script',  // one of ['script', 'module']
+        ecmaVersion: 5,
+        childVisitorKeys: null,
+        fallback: 'iteration'
+    };
+}
+
+function updateDeeply(target, override) {
+    var key, val;
+
+    function isHashObject(target) {
+        return typeof target === 'object' && target instanceof Object && !(target instanceof Array) && !(target instanceof RegExp);
+    }
+
+    for (key in override) {
+        if (override.hasOwnProperty(key)) {
+            val = override[key];
+            if (isHashObject(val)) {
+                if (isHashObject(target[key])) {
+                    updateDeeply(target[key], val);
+                } else {
+                    target[key] = updateDeeply({}, val);
+                }
+            } else {
+                target[key] = val;
+            }
+        }
+    }
+    return target;
+}
+
+/**
+ * Main interface function. Takes an Esprima syntax tree and returns the
+ * analyzed scopes.
+ * @function analyze
+ * @param {esprima.Tree} tree
+ * @param {Object} providedOptions - Options that tailor the scope analysis
+ * @param {boolean} [providedOptions.optimistic=false] - the optimistic flag
+ * @param {boolean} [providedOptions.directive=false]- the directive flag
+ * @param {boolean} [providedOptions.ignoreEval=false]- whether to check 'eval()' calls
+ * @param {boolean} [providedOptions.nodejsScope=false]- whether the whole
+ * script is executed under node.js environment. When enabled, escope adds
+ * a function scope immediately following the global scope.
+ * @param {boolean} [providedOptions.impliedStrict=false]- implied strict mode
+ * (if ecmaVersion >= 5).
+ * @param {string} [providedOptions.sourceType='script']- the source type of the script. one of 'script' and 'module'
+ * @param {number} [providedOptions.ecmaVersion=5]- which ECMAScript version is considered
+ * @param {Object} [providedOptions.childVisitorKeys=null] - Additional known visitor keys. See [esrecurse](https://github.com/estools/esrecurse)'s the `childVisitorKeys` option.
+ * @param {string} [providedOptions.fallback='iteration'] - A kind of the fallback in order to encounter with unknown node. See [esrecurse](https://github.com/estools/esrecurse)'s the `fallback` option.
+ * @return {ScopeManager}
+ */
+export function analyze(tree, providedOptions) {
+    var scopeManager, referencer, options;
+
+    options = updateDeeply(defaultOptions(), providedOptions);
+
+    scopeManager = new ScopeManager(options);
+
+    referencer = new Referencer(options, scopeManager);
+    referencer.visit(tree);
+
+    assert(scopeManager.__currentScope === null, 'currentScope should be null.');
+
+    return scopeManager;
+}
+
+export {
+    /** @name module:escope.version */
+    version,
+    /** @name module:escope.Reference */
+    Reference,
+    /** @name module:escope.Variable */
+    Variable,
+    /** @name module:escope.Scope */
+    Scope,
+    /** @name module:escope.ScopeManager */
+    ScopeManager
+};
+
+
+/* vim: set sw=4 ts=4 et tw=80 : */
diff --git a/node_modules/escope/src/pattern-visitor.js b/node_modules/escope/src/pattern-visitor.js
new file mode 100644
index 000000000..b98e98ad2
--- /dev/null
+++ b/node_modules/escope/src/pattern-visitor.js
@@ -0,0 +1,134 @@
+/*
+  Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+import { Syntax } from 'estraverse';
+import esrecurse from 'esrecurse';
+
+function getLast(xs) {
+    return xs[xs.length - 1] || null;
+}
+
+export default class PatternVisitor extends esrecurse.Visitor {
+    static isPattern(node) {
+        var nodeType = node.type;
+        return (
+            nodeType === Syntax.Identifier ||
+            nodeType === Syntax.ObjectPattern ||
+            nodeType === Syntax.ArrayPattern ||
+            nodeType === Syntax.SpreadElement ||
+            nodeType === Syntax.RestElement ||
+            nodeType === Syntax.AssignmentPattern
+        );
+    }
+
+    constructor(options, rootPattern, callback) {
+        super(null, options);
+        this.rootPattern = rootPattern;
+        this.callback = callback;
+        this.assignments = [];
+        this.rightHandNodes = [];
+        this.restElements = [];
+    }
+
+    Identifier(pattern) {
+        const lastRestElement = getLast(this.restElements);
+        this.callback(pattern, {
+            topLevel: pattern === this.rootPattern,
+            rest: lastRestElement != null && lastRestElement.argument === pattern,
+            assignments: this.assignments
+        });
+    }
+
+    Property(property) {
+        // Computed property's key is a right hand node.
+        if (property.computed) {
+            this.rightHandNodes.push(property.key);
+        }
+
+        // If it's shorthand, its key is same as its value.
+        // If it's shorthand and has its default value, its key is same as its value.left (the value is AssignmentPattern).
+        // If it's not shorthand, the name of new variable is its value's.
+        this.visit(property.value);
+    }
+
+    ArrayPattern(pattern) {
+        var i, iz, element;
+        for (i = 0, iz = pattern.elements.length; i < iz; ++i) {
+            element = pattern.elements[i];
+            this.visit(element);
+        }
+    }
+
+    AssignmentPattern(pattern) {
+        this.assignments.push(pattern);
+        this.visit(pattern.left);
+        this.rightHandNodes.push(pattern.right);
+        this.assignments.pop();
+    }
+
+    RestElement(pattern) {
+        this.restElements.push(pattern);
+        this.visit(pattern.argument);
+        this.restElements.pop();
+    }
+
+    MemberExpression(node) {
+        // Computed property's key is a right hand node.
+        if (node.computed) {
+            this.rightHandNodes.push(node.property);
+        }
+        // the object is only read, write to its property.
+        this.rightHandNodes.push(node.object);
+    }
+
+    //
+    // ForInStatement.left and AssignmentExpression.left are LeftHandSideExpression.
+    // By spec, LeftHandSideExpression is Pattern or MemberExpression.
+    //   (see also: https://github.com/estree/estree/pull/20#issuecomment-74584758)
+    // But espree 2.0 and esprima 2.0 parse to ArrayExpression, ObjectExpression, etc...
+    //
+
+    SpreadElement(node) {
+        this.visit(node.argument);
+    }
+
+    ArrayExpression(node) {
+        node.elements.forEach(this.visit, this);
+    }
+
+    AssignmentExpression(node) {
+        this.assignments.push(node);
+        this.visit(node.left);
+        this.rightHandNodes.push(node.right);
+        this.assignments.pop();
+    }
+
+    CallExpression(node) {
+        // arguments are right hand nodes.
+        node.arguments.forEach(a => { this.rightHandNodes.push(a); });
+        this.visit(node.callee);
+    }
+}
+
+/* vim: set sw=4 ts=4 et tw=80 : */
diff --git a/node_modules/escope/src/reference.js b/node_modules/escope/src/reference.js
new file mode 100644
index 000000000..7f273a363
--- /dev/null
+++ b/node_modules/escope/src/reference.js
@@ -0,0 +1,154 @@
+/*
+  Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+const READ = 0x1;
+const WRITE = 0x2;
+const RW = READ | WRITE;
+
+/**
+ * A Reference represents a single occurrence of an identifier in code.
+ * @class Reference
+ */
+export default class Reference {
+    constructor(ident, scope, flag,  writeExpr, maybeImplicitGlobal, partial, init) {
+        /**
+         * Identifier syntax node.
+         * @member {esprima#Identifier} Reference#identifier
+         */
+        this.identifier = ident;
+        /**
+         * Reference to the enclosing Scope.
+         * @member {Scope} Reference#from
+         */
+        this.from = scope;
+        /**
+         * Whether the reference comes from a dynamic scope (such as 'eval',
+         * 'with', etc.), and may be trapped by dynamic scopes.
+         * @member {boolean} Reference#tainted
+         */
+        this.tainted = false;
+        /**
+         * The variable this reference is resolved with.
+         * @member {Variable} Reference#resolved
+         */
+        this.resolved = null;
+        /**
+         * The read-write mode of the reference. (Value is one of {@link
+         * Reference.READ}, {@link Reference.RW}, {@link Reference.WRITE}).
+         * @member {number} Reference#flag
+         * @private
+         */
+        this.flag = flag;
+        if (this.isWrite()) {
+            /**
+             * If reference is writeable, this is the tree being written to it.
+             * @member {esprima#Node} Reference#writeExpr
+             */
+            this.writeExpr = writeExpr;
+            /**
+             * Whether the Reference might refer to a partial value of writeExpr.
+             * @member {boolean} Reference#partial
+             */
+            this.partial = partial;
+            /**
+             * Whether the Reference is to write of initialization.
+             * @member {boolean} Reference#init
+             */
+            this.init = init;
+        }
+        this.__maybeImplicitGlobal = maybeImplicitGlobal;
+    }
+
+    /**
+     * Whether the reference is static.
+     * @method Reference#isStatic
+     * @return {boolean}
+     */
+    isStatic() {
+        return !this.tainted && this.resolved && this.resolved.scope.isStatic();
+    }
+
+    /**
+     * Whether the reference is writeable.
+     * @method Reference#isWrite
+     * @return {boolean}
+     */
+    isWrite() {
+        return !!(this.flag & Reference.WRITE);
+    }
+
+    /**
+     * Whether the reference is readable.
+     * @method Reference#isRead
+     * @return {boolean}
+     */
+    isRead() {
+        return !!(this.flag & Reference.READ);
+    }
+
+    /**
+     * Whether the reference is read-only.
+     * @method Reference#isReadOnly
+     * @return {boolean}
+     */
+    isReadOnly() {
+        return this.flag === Reference.READ;
+    }
+
+    /**
+     * Whether the reference is write-only.
+     * @method Reference#isWriteOnly
+     * @return {boolean}
+     */
+    isWriteOnly() {
+        return this.flag === Reference.WRITE;
+    }
+
+    /**
+     * Whether the reference is read-write.
+     * @method Reference#isReadWrite
+     * @return {boolean}
+     */
+    isReadWrite() {
+        return this.flag === Reference.RW;
+    }
+}
+
+/**
+ * @constant Reference.READ
+ * @private
+ */
+Reference.READ = READ;
+/**
+ * @constant Reference.WRITE
+ * @private
+ */
+Reference.WRITE = WRITE;
+/**
+ * @constant Reference.RW
+ * @private
+ */
+Reference.RW = RW;
+
+/* vim: set sw=4 ts=4 et tw=80 : */
diff --git a/node_modules/escope/src/referencer.js b/node_modules/escope/src/referencer.js
new file mode 100644
index 000000000..bd810808c
--- /dev/null
+++ b/node_modules/escope/src/referencer.js
@@ -0,0 +1,584 @@
+/*
+  Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+import { Syntax } from 'estraverse';
+import esrecurse from 'esrecurse';
+import Reference from './reference';
+import Variable from './variable';
+import PatternVisitor from './pattern-visitor';
+import { ParameterDefinition, Definition } from './definition';
+import assert from 'assert';
+
+function traverseIdentifierInPattern(options, rootPattern, referencer, callback) {
+    // Call the callback at left hand identifier nodes, and Collect right hand nodes.
+    var visitor = new PatternVisitor(options, rootPattern, callback);
+    visitor.visit(rootPattern);
+
+    // Process the right hand nodes recursively.
+    if (referencer != null) {
+        visitor.rightHandNodes.forEach(referencer.visit, referencer);
+    }
+}
+
+// Importing ImportDeclaration.
+// http://people.mozilla.org/~jorendorff/es6-draft.html#sec-moduledeclarationinstantiation
+// https://github.com/estree/estree/blob/master/es6.md#importdeclaration
+// FIXME: Now, we don't create module environment, because the context is
+// implementation dependent.
+
+class Importer extends esrecurse.Visitor {
+    constructor(declaration, referencer) {
+        super(null, referencer.options);
+        this.declaration = declaration;
+        this.referencer = referencer;
+    }
+
+    visitImport(id, specifier) {
+        this.referencer.visitPattern(id, (pattern) => {
+            this.referencer.currentScope().__define(pattern,
+                new Definition(
+                    Variable.ImportBinding,
+                    pattern,
+                    specifier,
+                    this.declaration,
+                    null,
+                    null
+                    ));
+        });
+    }
+
+    ImportNamespaceSpecifier(node) {
+        let local = (node.local || node.id);
+        if (local) {
+            this.visitImport(local, node);
+        }
+    }
+
+    ImportDefaultSpecifier(node) {
+        let local = (node.local || node.id);
+        this.visitImport(local, node);
+    }
+
+    ImportSpecifier(node) {
+        let local = (node.local || node.id);
+        if (node.name) {
+            this.visitImport(node.name, node);
+        } else {
+            this.visitImport(local, node);
+        }
+    }
+}
+
+// Referencing variables and creating bindings.
+export default class Referencer extends esrecurse.Visitor {
+    constructor(options, scopeManager) {
+        super(null, options);
+        this.options = options;
+        this.scopeManager = scopeManager;
+        this.parent = null;
+        this.isInnerMethodDefinition = false;
+    }
+
+    currentScope() {
+        return this.scopeManager.__currentScope;
+    }
+
+    close(node) {
+        while (this.currentScope() && node === this.currentScope().block) {
+            this.scopeManager.__currentScope = this.currentScope().__close(this.scopeManager);
+        }
+    }
+
+    pushInnerMethodDefinition(isInnerMethodDefinition) {
+        var previous = this.isInnerMethodDefinition;
+        this.isInnerMethodDefinition = isInnerMethodDefinition;
+        return previous;
+    }
+
+    popInnerMethodDefinition(isInnerMethodDefinition) {
+        this.isInnerMethodDefinition = isInnerMethodDefinition;
+    }
+
+    materializeTDZScope(node, iterationNode) {
+        // http://people.mozilla.org/~jorendorff/es6-draft.html#sec-runtime-semantics-forin-div-ofexpressionevaluation-abstract-operation
+        // TDZ scope hides the declaration's names.
+        this.scopeManager.__nestTDZScope(node, iterationNode);
+        this.visitVariableDeclaration(this.currentScope(), Variable.TDZ, iterationNode.left, 0, true);
+    }
+
+    materializeIterationScope(node) {
+        // Generate iteration scope for upper ForIn/ForOf Statements.
+        var letOrConstDecl;
+        this.scopeManager.__nestForScope(node);
+        letOrConstDecl = node.left;
+        this.visitVariableDeclaration(this.currentScope(), Variable.Variable, letOrConstDecl, 0);
+        this.visitPattern(letOrConstDecl.declarations[0].id, (pattern) => {
+            this.currentScope().__referencing(pattern, Reference.WRITE, node.right, null, true, true);
+        });
+    }
+
+    referencingDefaultValue(pattern, assignments, maybeImplicitGlobal, init) {
+        const scope = this.currentScope();
+        assignments.forEach(assignment => {
+            scope.__referencing(
+                pattern,
+                Reference.WRITE,
+                assignment.right,
+                maybeImplicitGlobal,
+                pattern !== assignment.left,
+                init);
+        });
+    }
+
+    visitPattern(node, options, callback) {
+        if (typeof options === 'function') {
+            callback = options;
+            options = {processRightHandNodes: false}
+        }
+        traverseIdentifierInPattern(
+            this.options,
+            node,
+            options.processRightHandNodes ? this : null,
+            callback);
+    }
+
+    visitFunction(node) {
+        var i, iz;
+        // FunctionDeclaration name is defined in upper scope
+        // NOTE: Not referring variableScope. It is intended.
+        // Since
+        //  in ES5, FunctionDeclaration should be in FunctionBody.
+        //  in ES6, FunctionDeclaration should be block scoped.
+        if (node.type === Syntax.FunctionDeclaration) {
+            // id is defined in upper scope
+            this.currentScope().__define(node.id,
+                    new Definition(
+                        Variable.FunctionName,
+                        node.id,
+                        node,
+                        null,
+                        null,
+                        null
+                    ));
+        }
+
+        // FunctionExpression with name creates its special scope;
+        // FunctionExpressionNameScope.
+        if (node.type === Syntax.FunctionExpression && node.id) {
+            this.scopeManager.__nestFunctionExpressionNameScope(node);
+        }
+
+        // Consider this function is in the MethodDefinition.
+        this.scopeManager.__nestFunctionScope(node, this.isInnerMethodDefinition);
+
+        // Process parameter declarations.
+        for (i = 0, iz = node.params.length; i < iz; ++i) {
+            this.visitPattern(node.params[i], {processRightHandNodes: true}, (pattern, info) => {
+                this.currentScope().__define(pattern,
+                    new ParameterDefinition(
+                        pattern,
+                        node,
+                        i,
+                        info.rest
+                    ));
+
+                this.referencingDefaultValue(pattern, info.assignments, null, true);
+            });
+        }
+
+        // if there's a rest argument, add that
+        if (node.rest) {
+            this.visitPattern({
+                type: 'RestElement',
+                argument: node.rest
+            }, (pattern) => {
+                this.currentScope().__define(pattern,
+                    new ParameterDefinition(
+                        pattern,
+                        node,
+                        node.params.length,
+                        true
+                    ));
+            });
+        }
+
+        // Skip BlockStatement to prevent creating BlockStatement scope.
+        if (node.body.type === Syntax.BlockStatement) {
+            this.visitChildren(node.body);
+        } else {
+            this.visit(node.body);
+        }
+
+        this.close(node);
+    }
+
+    visitClass(node) {
+        if (node.type === Syntax.ClassDeclaration) {
+            this.currentScope().__define(node.id,
+                    new Definition(
+                        Variable.ClassName,
+                        node.id,
+                        node,
+                        null,
+                        null,
+                        null
+                    ));
+        }
+
+        // FIXME: Maybe consider TDZ.
+        this.visit(node.superClass);
+
+        this.scopeManager.__nestClassScope(node);
+
+        if (node.id) {
+            this.currentScope().__define(node.id,
+                    new Definition(
+                        Variable.ClassName,
+                        node.id,
+                        node
+                    ));
+        }
+        this.visit(node.body);
+
+        this.close(node);
+    }
+
+    visitProperty(node) {
+        var previous, isMethodDefinition;
+        if (node.computed) {
+            this.visit(node.key);
+        }
+
+        isMethodDefinition = node.type === Syntax.MethodDefinition;
+        if (isMethodDefinition) {
+            previous = this.pushInnerMethodDefinition(true);
+        }
+        this.visit(node.value);
+        if (isMethodDefinition) {
+            this.popInnerMethodDefinition(previous);
+        }
+    }
+
+    visitForIn(node) {
+        if (node.left.type === Syntax.VariableDeclaration && node.left.kind !== 'var') {
+            this.materializeTDZScope(node.right, node);
+            this.visit(node.right);
+            this.close(node.right);
+
+            this.materializeIterationScope(node);
+            this.visit(node.body);
+            this.close(node);
+        } else {
+            if (node.left.type === Syntax.VariableDeclaration) {
+                this.visit(node.left);
+                this.visitPattern(node.left.declarations[0].id, (pattern) => {
+                    this.currentScope().__referencing(pattern, Reference.WRITE, node.right, null, true, true);
+                });
+            } else {
+                this.visitPattern(node.left, {processRightHandNodes: true}, (pattern, info) => {
+                    var maybeImplicitGlobal = null;
+                    if (!this.currentScope().isStrict) {
+                        maybeImplicitGlobal = {
+                            pattern: pattern,
+                            node: node
+                        };
+                    }
+                    this.referencingDefaultValue(pattern, info.assignments, maybeImplicitGlobal, false);
+                    this.currentScope().__referencing(pattern, Reference.WRITE, node.right, maybeImplicitGlobal, true, false);
+                });
+            }
+            this.visit(node.right);
+            this.visit(node.body);
+        }
+    }
+
+    visitVariableDeclaration(variableTargetScope, type, node, index, fromTDZ) {
+        // If this was called to initialize a TDZ scope, this needs to make definitions, but doesn't make references.
+        var decl, init;
+
+        decl = node.declarations[index];
+        init = decl.init;
+        this.visitPattern(decl.id, {processRightHandNodes: !fromTDZ}, (pattern, info) => {
+            variableTargetScope.__define(pattern,
+                new Definition(
+                    type,
+                    pattern,
+                    decl,
+                    node,
+                    index,
+                    node.kind
+                ));
+
+            if (!fromTDZ) {
+                this.referencingDefaultValue(pattern, info.assignments, null, true);
+            }
+            if (init) {
+                this.currentScope().__referencing(pattern, Reference.WRITE, init, null, !info.topLevel, true);
+            }
+        });
+    }
+
+    AssignmentExpression(node) {
+        if (PatternVisitor.isPattern(node.left)) {
+            if (node.operator === '=') {
+                this.visitPattern(node.left, {processRightHandNodes: true}, (pattern, info) => {
+                    var maybeImplicitGlobal = null;
+                    if (!this.currentScope().isStrict) {
+                        maybeImplicitGlobal = {
+                            pattern: pattern,
+                            node: node
+                        };
+                    }
+                    this.referencingDefaultValue(pattern, info.assignments, maybeImplicitGlobal, false);
+                    this.currentScope().__referencing(pattern, Reference.WRITE, node.right, maybeImplicitGlobal, !info.topLevel, false);
+                });
+            } else {
+                this.currentScope().__referencing(node.left, Reference.RW, node.right);
+            }
+        } else {
+            this.visit(node.left);
+        }
+        this.visit(node.right);
+    }
+
+    CatchClause(node) {
+        this.scopeManager.__nestCatchScope(node);
+
+        this.visitPattern(node.param, {processRightHandNodes: true}, (pattern, info) => {
+            this.currentScope().__define(pattern,
+                new Definition(
+                    Variable.CatchClause,
+                    node.param,
+                    node,
+                    null,
+                    null,
+                    null
+                ));
+            this.referencingDefaultValue(pattern, info.assignments, null, true);
+        });
+        this.visit(node.body);
+
+        this.close(node);
+    }
+
+    Program(node) {
+        this.scopeManager.__nestGlobalScope(node);
+
+        if (this.scopeManager.__isNodejsScope()) {
+            // Force strictness of GlobalScope to false when using node.js scope.
+            this.currentScope().isStrict = false;
+            this.scopeManager.__nestFunctionScope(node, false);
+        }
+
+        if (this.scopeManager.__isES6() && this.scopeManager.isModule()) {
+            this.scopeManager.__nestModuleScope(node);
+        }
+
+        if (this.scopeManager.isStrictModeSupported() && this.scopeManager.isImpliedStrict()) {
+            this.currentScope().isStrict = true;
+        }
+
+        this.visitChildren(node);
+        this.close(node);
+    }
+
+    Identifier(node) {
+        this.currentScope().__referencing(node);
+    }
+
+    UpdateExpression(node) {
+        if (PatternVisitor.isPattern(node.argument)) {
+            this.currentScope().__referencing(node.argument, Reference.RW, null);
+        } else {
+            this.visitChildren(node);
+        }
+    }
+
+    MemberExpression(node) {
+        this.visit(node.object);
+        if (node.computed) {
+            this.visit(node.property);
+        }
+    }
+
+    Property(node) {
+        this.visitProperty(node);
+    }
+
+    MethodDefinition(node) {
+        this.visitProperty(node);
+    }
+
+    BreakStatement() {}
+
+    ContinueStatement() {}
+
+    LabeledStatement(node) {
+        this.visit(node.body);
+    }
+
+    ForStatement(node) {
+        // Create ForStatement declaration.
+        // NOTE: In ES6, ForStatement dynamically generates
+        // per iteration environment. However, escope is
+        // a static analyzer, we only generate one scope for ForStatement.
+        if (node.init && node.init.type === Syntax.VariableDeclaration && node.init.kind !== 'var') {
+            this.scopeManager.__nestForScope(node);
+        }
+
+        this.visitChildren(node);
+
+        this.close(node);
+    }
+
+    ClassExpression(node) {
+        this.visitClass(node);
+    }
+
+    ClassDeclaration(node) {
+        this.visitClass(node);
+    }
+
+    CallExpression(node) {
+        // Check this is direct call to eval
+        if (!this.scopeManager.__ignoreEval() && node.callee.type === Syntax.Identifier && node.callee.name === 'eval') {
+            // NOTE: This should be `variableScope`. Since direct eval call always creates Lexical environment and
+            // let / const should be enclosed into it. Only VariableDeclaration affects on the caller's environment.
+            this.currentScope().variableScope.__detectEval();
+        }
+        this.visitChildren(node);
+    }
+
+    BlockStatement(node) {
+        if (this.scopeManager.__isES6()) {
+            this.scopeManager.__nestBlockScope(node);
+        }
+
+        this.visitChildren(node);
+
+        this.close(node);
+    }
+
+    ThisExpression() {
+        this.currentScope().variableScope.__detectThis();
+    }
+
+    WithStatement(node) {
+        this.visit(node.object);
+        // Then nest scope for WithStatement.
+        this.scopeManager.__nestWithScope(node);
+
+        this.visit(node.body);
+
+        this.close(node);
+    }
+
+    VariableDeclaration(node) {
+        var variableTargetScope, i, iz, decl;
+        variableTargetScope = (node.kind === 'var') ? this.currentScope().variableScope : this.currentScope();
+        for (i = 0, iz = node.declarations.length; i < iz; ++i) {
+            decl = node.declarations[i];
+            this.visitVariableDeclaration(variableTargetScope, Variable.Variable, node, i);
+            if (decl.init) {
+                this.visit(decl.init);
+            }
+        }
+    }
+
+    // sec 13.11.8
+    SwitchStatement(node) {
+        var i, iz;
+
+        this.visit(node.discriminant);
+
+        if (this.scopeManager.__isES6()) {
+            this.scopeManager.__nestSwitchScope(node);
+        }
+
+        for (i = 0, iz = node.cases.length; i < iz; ++i) {
+            this.visit(node.cases[i]);
+        }
+
+        this.close(node);
+    }
+
+    FunctionDeclaration(node) {
+        this.visitFunction(node);
+    }
+
+    FunctionExpression(node) {
+        this.visitFunction(node);
+    }
+
+    ForOfStatement(node) {
+        this.visitForIn(node);
+    }
+
+    ForInStatement(node) {
+        this.visitForIn(node);
+    }
+
+    ArrowFunctionExpression(node) {
+        this.visitFunction(node);
+    }
+
+    ImportDeclaration(node) {
+        var importer;
+
+        assert(this.scopeManager.__isES6() && this.scopeManager.isModule(), 'ImportDeclaration should appear when the mode is ES6 and in the module context.');
+
+        importer = new Importer(node, this);
+        importer.visit(node);
+    }
+
+    visitExportDeclaration(node) {
+        if (node.source) {
+            return;
+        }
+        if (node.declaration) {
+            this.visit(node.declaration);
+            return;
+        }
+
+        this.visitChildren(node);
+    }
+
+    ExportDeclaration(node) {
+        this.visitExportDeclaration(node);
+    }
+
+    ExportNamedDeclaration(node) {
+        this.visitExportDeclaration(node);
+    }
+
+    ExportSpecifier(node) {
+        let local = (node.id || node.local);
+        this.visit(local);
+    }
+
+    MetaProperty() {
+        // do nothing.
+    }
+}
+
+/* vim: set sw=4 ts=4 et tw=80 : */
diff --git a/node_modules/escope/src/scope-manager.js b/node_modules/escope/src/scope-manager.js
new file mode 100644
index 000000000..024535d7c
--- /dev/null
+++ b/node_modules/escope/src/scope-manager.js
@@ -0,0 +1,245 @@
+/*
+  Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+import WeakMap from 'es6-weak-map';
+import Scope from './scope';
+import assert from 'assert';
+
+import {
+    GlobalScope,
+    CatchScope,
+    WithScope,
+    ModuleScope,
+    ClassScope,
+    SwitchScope,
+    FunctionScope,
+    ForScope,
+    TDZScope,
+    FunctionExpressionNameScope,
+    BlockScope
+} from './scope';
+
+/**
+ * @class ScopeManager
+ */
+export default class ScopeManager {
+    constructor(options) {
+        this.scopes = [];
+        this.globalScope = null;
+        this.__nodeToScope = new WeakMap();
+        this.__currentScope = null;
+        this.__options = options;
+        this.__declaredVariables = new WeakMap();
+    }
+
+    __useDirective() {
+        return this.__options.directive;
+    }
+
+    __isOptimistic() {
+        return this.__options.optimistic;
+    }
+
+    __ignoreEval() {
+        return this.__options.ignoreEval;
+    }
+
+    __isNodejsScope() {
+        return this.__options.nodejsScope;
+    }
+
+    isModule() {
+        return this.__options.sourceType === 'module';
+    }
+
+    isImpliedStrict() {
+        return this.__options.impliedStrict;
+    }
+
+    isStrictModeSupported() {
+        return this.__options.ecmaVersion >= 5;
+    }
+
+    // Returns appropriate scope for this node.
+    __get(node) {
+        return this.__nodeToScope.get(node);
+    }
+
+    /**
+     * Get variables that are declared by the node.
+     *
+     * "are declared by the node" means the node is same as `Variable.defs[].node` or `Variable.defs[].parent`.
+     * If the node declares nothing, this method returns an empty array.
+     * CAUTION: This API is experimental. See https://github.com/estools/escope/pull/69 for more details.
+     *
+     * @param {Esprima.Node} node - a node to get.
+     * @returns {Variable[]} variables that declared by the node.
+     */
+    getDeclaredVariables(node) {
+        return this.__declaredVariables.get(node) || [];
+    }
+
+    /**
+     * acquire scope from node.
+     * @method ScopeManager#acquire
+     * @param {Esprima.Node} node - node for the acquired scope.
+     * @param {boolean=} inner - look up the most inner scope, default value is false.
+     * @return {Scope?}
+     */
+    acquire(node, inner) {
+        var scopes, scope, i, iz;
+
+        function predicate(scope) {
+            if (scope.type === 'function' && scope.functionExpressionScope) {
+                return false;
+            }
+            if (scope.type === 'TDZ') {
+                return false;
+            }
+            return true;
+        }
+
+        scopes = this.__get(node);
+        if (!scopes || scopes.length === 0) {
+            return null;
+        }
+
+        // Heuristic selection from all scopes.
+        // If you would like to get all scopes, please use ScopeManager#acquireAll.
+        if (scopes.length === 1) {
+            return scopes[0];
+        }
+
+        if (inner) {
+            for (i = scopes.length - 1; i >= 0; --i) {
+                scope = scopes[i];
+                if (predicate(scope)) {
+                    return scope;
+                }
+            }
+        } else {
+            for (i = 0, iz = scopes.length; i < iz; ++i) {
+                scope = scopes[i];
+                if (predicate(scope)) {
+                    return scope;
+                }
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * acquire all scopes from node.
+     * @method ScopeManager#acquireAll
+     * @param {Esprima.Node} node - node for the acquired scope.
+     * @return {Scope[]?}
+     */
+    acquireAll(node) {
+        return this.__get(node);
+    }
+
+    /**
+     * release the node.
+     * @method ScopeManager#release
+     * @param {Esprima.Node} node - releasing node.
+     * @param {boolean=} inner - look up the most inner scope, default value is false.
+     * @return {Scope?} upper scope for the node.
+     */
+    release(node, inner) {
+        var scopes, scope;
+        scopes = this.__get(node);
+        if (scopes && scopes.length) {
+            scope = scopes[0].upper;
+            if (!scope) {
+                return null;
+            }
+            return this.acquire(scope.block, inner);
+        }
+        return null;
+    }
+
+    attach() { }
+
+    detach() { }
+
+    __nestScope(scope) {
+        if (scope instanceof GlobalScope) {
+            assert(this.__currentScope === null);
+            this.globalScope = scope;
+        }
+        this.__currentScope = scope;
+        return scope;
+    }
+
+    __nestGlobalScope(node) {
+        return this.__nestScope(new GlobalScope(this, node));
+    }
+
+    __nestBlockScope(node, isMethodDefinition) {
+        return this.__nestScope(new BlockScope(this, this.__currentScope, node));
+    }
+
+    __nestFunctionScope(node, isMethodDefinition) {
+        return this.__nestScope(new FunctionScope(this, this.__currentScope, node, isMethodDefinition));
+    }
+
+    __nestForScope(node) {
+        return this.__nestScope(new ForScope(this, this.__currentScope, node));
+    }
+
+    __nestCatchScope(node) {
+        return this.__nestScope(new CatchScope(this, this.__currentScope, node));
+    }
+
+    __nestWithScope(node) {
+        return this.__nestScope(new WithScope(this, this.__currentScope, node));
+    }
+
+    __nestClassScope(node) {
+        return this.__nestScope(new ClassScope(this, this.__currentScope, node));
+    }
+
+    __nestSwitchScope(node) {
+        return this.__nestScope(new SwitchScope(this, this.__currentScope, node));
+    }
+
+    __nestModuleScope(node) {
+        return this.__nestScope(new ModuleScope(this, this.__currentScope, node));
+    }
+
+    __nestTDZScope(node) {
+        return this.__nestScope(new TDZScope(this, this.__currentScope, node));
+    }
+
+    __nestFunctionExpressionNameScope(node) {
+        return this.__nestScope(new FunctionExpressionNameScope(this, this.__currentScope, node));
+    }
+
+    __isES6() {
+        return this.__options.ecmaVersion >= 6;
+    }
+}
+
+/* vim: set sw=4 ts=4 et tw=80 : */
diff --git a/node_modules/escope/src/scope.js b/node_modules/escope/src/scope.js
new file mode 100644
index 000000000..0e4d8c2d7
--- /dev/null
+++ b/node_modules/escope/src/scope.js
@@ -0,0 +1,647 @@
+/*
+  Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+import { Syntax } from 'estraverse';
+import Map from 'es6-map';
+
+import Reference from './reference';
+import Variable from './variable';
+import Definition from './definition';
+import assert from 'assert';
+
+function isStrictScope(scope, block, isMethodDefinition, useDirective) {
+    var body, i, iz, stmt, expr;
+
+    // When upper scope is exists and strict, inner scope is also strict.
+    if (scope.upper && scope.upper.isStrict) {
+        return true;
+    }
+
+    // ArrowFunctionExpression's scope is always strict scope.
+    if (block.type === Syntax.ArrowFunctionExpression) {
+        return true;
+    }
+
+    if (isMethodDefinition) {
+        return true;
+    }
+
+    if (scope.type === 'class' || scope.type === 'module') {
+        return true;
+    }
+
+    if (scope.type === 'block' || scope.type === 'switch') {
+        return false;
+    }
+
+    if (scope.type === 'function') {
+        if (block.type === Syntax.Program) {
+            body = block;
+        } else {
+            body = block.body;
+        }
+    } else if (scope.type === 'global') {
+        body = block;
+    } else {
+        return false;
+    }
+
+    // Search 'use strict' directive.
+    if (useDirective) {
+        for (i = 0, iz = body.body.length; i < iz; ++i) {
+            stmt = body.body[i];
+            if (stmt.type !== Syntax.DirectiveStatement) {
+                break;
+            }
+            if (stmt.raw === '"use strict"' || stmt.raw === '\'use strict\'') {
+                return true;
+            }
+        }
+    } else {
+        for (i = 0, iz = body.body.length; i < iz; ++i) {
+            stmt = body.body[i];
+            if (stmt.type !== Syntax.ExpressionStatement) {
+                break;
+            }
+            expr = stmt.expression;
+            if (expr.type !== Syntax.Literal || typeof expr.value !== 'string') {
+                break;
+            }
+            if (expr.raw != null) {
+                if (expr.raw === '"use strict"' || expr.raw === '\'use strict\'') {
+                    return true;
+                }
+            } else {
+                if (expr.value === 'use strict') {
+                    return true;
+                }
+            }
+        }
+    }
+    return false;
+}
+
+function registerScope(scopeManager, scope) {
+    var scopes;
+
+    scopeManager.scopes.push(scope);
+
+    scopes = scopeManager.__nodeToScope.get(scope.block);
+    if (scopes) {
+        scopes.push(scope);
+    } else {
+        scopeManager.__nodeToScope.set(scope.block, [ scope ]);
+    }
+}
+
+function shouldBeStatically(def) {
+    return (
+        (def.type === Variable.ClassName) ||
+        (def.type === Variable.Variable && def.parent.kind !== 'var')
+    );
+}
+
+/**
+ * @class Scope
+ */
+export default class Scope {
+    constructor(scopeManager, type, upperScope, block, isMethodDefinition) {
+        /**
+         * One of 'TDZ', 'module', 'block', 'switch', 'function', 'catch', 'with', 'function', 'class', 'global'.
+         * @member {String} Scope#type
+         */
+        this.type = type;
+         /**
+         * The scoped {@link Variable}s of this scope, as <code>{ Variable.name
+         * : Variable }</code>.
+         * @member {Map} Scope#set
+         */
+        this.set = new Map();
+        /**
+         * The tainted variables of this scope, as <code>{ Variable.name :
+         * boolean }</code>.
+         * @member {Map} Scope#taints */
+        this.taints = new Map();
+        /**
+         * Generally, through the lexical scoping of JS you can always know
+         * which variable an identifier in the source code refers to. There are
+         * a few exceptions to this rule. With 'global' and 'with' scopes you
+         * can only decide at runtime which variable a reference refers to.
+         * Moreover, if 'eval()' is used in a scope, it might introduce new
+         * bindings in this or its parent scopes.
+         * All those scopes are considered 'dynamic'.
+         * @member {boolean} Scope#dynamic
+         */
+        this.dynamic = this.type === 'global' || this.type === 'with';
+        /**
+         * A reference to the scope-defining syntax node.
+         * @member {esprima.Node} Scope#block
+         */
+        this.block = block;
+         /**
+         * The {@link Reference|references} that are not resolved with this scope.
+         * @member {Reference[]} Scope#through
+         */
+        this.through = [];
+         /**
+         * The scoped {@link Variable}s of this scope. In the case of a
+         * 'function' scope this includes the automatic argument <em>arguments</em> as
+         * its first element, as well as all further formal arguments.
+         * @member {Variable[]} Scope#variables
+         */
+        this.variables = [];
+         /**
+         * Any variable {@link Reference|reference} found in this scope. This
+         * includes occurrences of local variables as well as variables from
+         * parent scopes (including the global scope). For local variables
+         * this also includes defining occurrences (like in a 'var' statement).
+         * In a 'function' scope this does not include the occurrences of the
+         * formal parameter in the parameter list.
+         * @member {Reference[]} Scope#references
+         */
+        this.references = [];
+
+         /**
+         * For 'global' and 'function' scopes, this is a self-reference. For
+         * other scope types this is the <em>variableScope</em> value of the
+         * parent scope.
+         * @member {Scope} Scope#variableScope
+         */
+        this.variableScope =
+            (this.type === 'global' || this.type === 'function' || this.type === 'module') ? this : upperScope.variableScope;
+         /**
+         * Whether this scope is created by a FunctionExpression.
+         * @member {boolean} Scope#functionExpressionScope
+         */
+        this.functionExpressionScope = false;
+         /**
+         * Whether this is a scope that contains an 'eval()' invocation.
+         * @member {boolean} Scope#directCallToEvalScope
+         */
+        this.directCallToEvalScope = false;
+         /**
+         * @member {boolean} Scope#thisFound
+         */
+        this.thisFound = false;
+
+        this.__left = [];
+
+         /**
+         * Reference to the parent {@link Scope|scope}.
+         * @member {Scope} Scope#upper
+         */
+        this.upper = upperScope;
+         /**
+         * Whether 'use strict' is in effect in this scope.
+         * @member {boolean} Scope#isStrict
+         */
+        this.isStrict = isStrictScope(this, block, isMethodDefinition, scopeManager.__useDirective());
+
+         /**
+         * List of nested {@link Scope}s.
+         * @member {Scope[]} Scope#childScopes
+         */
+        this.childScopes = [];
+        if (this.upper) {
+            this.upper.childScopes.push(this);
+        }
+
+        this.__declaredVariables = scopeManager.__declaredVariables;
+
+        registerScope(scopeManager, this);
+    }
+
+    __shouldStaticallyClose(scopeManager) {
+        return (!this.dynamic || scopeManager.__isOptimistic());
+    }
+
+    __shouldStaticallyCloseForGlobal(ref) {
+        // On global scope, let/const/class declarations should be resolved statically.
+        var name = ref.identifier.name;
+        if (!this.set.has(name)) {
+            return false;
+        }
+
+        var variable = this.set.get(name);
+        var defs = variable.defs;
+        return defs.length > 0 && defs.every(shouldBeStatically);
+    }
+
+    __staticCloseRef(ref) {
+        if (!this.__resolve(ref)) {
+            this.__delegateToUpperScope(ref);
+        }
+    }
+
+    __dynamicCloseRef(ref) {
+        // notify all names are through to global
+        let current = this;
+        do {
+            current.through.push(ref);
+            current = current.upper;
+        } while (current);
+    }
+
+    __globalCloseRef(ref) {
+        // let/const/class declarations should be resolved statically.
+        // others should be resolved dynamically.
+        if (this.__shouldStaticallyCloseForGlobal(ref)) {
+            this.__staticCloseRef(ref);
+        } else {
+            this.__dynamicCloseRef(ref);
+        }
+    }
+
+    __close(scopeManager) {
+        var closeRef;
+        if (this.__shouldStaticallyClose(scopeManager)) {
+            closeRef = this.__staticCloseRef;
+        } else if (this.type !== 'global') {
+            closeRef = this.__dynamicCloseRef;
+        } else {
+            closeRef = this.__globalCloseRef;
+        }
+
+        // Try Resolving all references in this scope.
+        for (let i = 0, iz = this.__left.length; i < iz; ++i) {
+            let ref = this.__left[i];
+            closeRef.call(this, ref);
+        }
+        this.__left = null;
+
+        return this.upper;
+    }
+
+    __resolve(ref) {
+        var variable, name;
+        name = ref.identifier.name;
+        if (this.set.has(name)) {
+            variable = this.set.get(name);
+            variable.references.push(ref);
+            variable.stack = variable.stack && ref.from.variableScope === this.variableScope;
+            if (ref.tainted) {
+                variable.tainted = true;
+                this.taints.set(variable.name, true);
+            }
+            ref.resolved = variable;
+            return true;
+        }
+        return false;
+    }
+
+    __delegateToUpperScope(ref) {
+        if (this.upper) {
+            this.upper.__left.push(ref);
+        }
+        this.through.push(ref);
+    }
+
+    __addDeclaredVariablesOfNode(variable, node) {
+        if (node == null) {
+            return;
+        }
+
+        var variables = this.__declaredVariables.get(node);
+        if (variables == null) {
+            variables = [];
+            this.__declaredVariables.set(node, variables);
+        }
+        if (variables.indexOf(variable) === -1) {
+            variables.push(variable);
+        }
+    }
+
+    __defineGeneric(name, set, variables, node, def) {
+        var variable;
+
+        variable = set.get(name);
+        if (!variable) {
+            variable = new Variable(name, this);
+            set.set(name, variable);
+            variables.push(variable);
+        }
+
+        if (def) {
+            variable.defs.push(def);
+            if (def.type !== Variable.TDZ) {
+                this.__addDeclaredVariablesOfNode(variable, def.node);
+                this.__addDeclaredVariablesOfNode(variable, def.parent);
+            }
+        }
+        if (node) {
+            variable.identifiers.push(node);
+        }
+    }
+
+    __define(node, def) {
+        if (node && node.type === Syntax.Identifier) {
+            this.__defineGeneric(
+                    node.name,
+                    this.set,
+                    this.variables,
+                    node,
+                    def);
+        }
+    }
+
+    __referencing(node, assign, writeExpr, maybeImplicitGlobal, partial, init) {
+        // because Array element may be null
+        if (!node || node.type !== Syntax.Identifier) {
+            return;
+        }
+
+        // Specially handle like `this`.
+        if (node.name === 'super') {
+            return;
+        }
+
+        let ref = new Reference(node, this, assign || Reference.READ, writeExpr, maybeImplicitGlobal, !!partial, !!init);
+        this.references.push(ref);
+        this.__left.push(ref);
+    }
+
+    __detectEval() {
+        var current;
+        current = this;
+        this.directCallToEvalScope = true;
+        do {
+            current.dynamic = true;
+            current = current.upper;
+        } while (current);
+    }
+
+    __detectThis() {
+        this.thisFound = true;
+    }
+
+    __isClosed() {
+        return this.__left === null;
+    }
+
+    /**
+     * returns resolved {Reference}
+     * @method Scope#resolve
+     * @param {Esprima.Identifier} ident - identifier to be resolved.
+     * @return {Reference}
+     */
+    resolve(ident) {
+        var ref, i, iz;
+        assert(this.__isClosed(), 'Scope should be closed.');
+        assert(ident.type === Syntax.Identifier, 'Target should be identifier.');
+        for (i = 0, iz = this.references.length; i < iz; ++i) {
+            ref = this.references[i];
+            if (ref.identifier === ident) {
+                return ref;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * returns this scope is static
+     * @method Scope#isStatic
+     * @return {boolean}
+     */
+    isStatic() {
+        return !this.dynamic;
+    }
+
+    /**
+     * returns this scope has materialized arguments
+     * @method Scope#isArgumentsMaterialized
+     * @return {boolean}
+     */
+    isArgumentsMaterialized() {
+        return true;
+    }
+
+    /**
+     * returns this scope has materialized `this` reference
+     * @method Scope#isThisMaterialized
+     * @return {boolean}
+     */
+    isThisMaterialized() {
+        return true;
+    }
+
+    isUsedName(name) {
+        if (this.set.has(name)) {
+            return true;
+        }
+        for (var i = 0, iz = this.through.length; i < iz; ++i) {
+            if (this.through[i].identifier.name === name) {
+                return true;
+            }
+        }
+        return false;
+    }
+}
+
+export class GlobalScope extends Scope {
+    constructor(scopeManager, block) {
+        super(scopeManager, 'global', null, block, false);
+        this.implicit = {
+            set: new Map(),
+            variables: [],
+            /**
+            * List of {@link Reference}s that are left to be resolved (i.e. which
+            * need to be linked to the variable they refer to).
+            * @member {Reference[]} Scope#implicit#left
+            */
+            left: []
+        };
+    }
+
+    __close(scopeManager) {
+        let implicit = [];
+        for (let i = 0, iz = this.__left.length; i < iz; ++i) {
+            let ref = this.__left[i];
+            if (ref.__maybeImplicitGlobal && !this.set.has(ref.identifier.name)) {
+                implicit.push(ref.__maybeImplicitGlobal);
+            }
+        }
+
+        // create an implicit global variable from assignment expression
+        for (let i = 0, iz = implicit.length; i < iz; ++i) {
+            let info = implicit[i];
+            this.__defineImplicit(info.pattern,
+                    new Definition(
+                        Variable.ImplicitGlobalVariable,
+                        info.pattern,
+                        info.node,
+                        null,
+                        null,
+                        null
+                    ));
+
+        }
+
+        this.implicit.left = this.__left;
+
+        return super.__close(scopeManager);
+    }
+
+    __defineImplicit(node, def) {
+        if (node && node.type === Syntax.Identifier) {
+            this.__defineGeneric(
+                    node.name,
+                    this.implicit.set,
+                    this.implicit.variables,
+                    node,
+                    def);
+        }
+    }
+}
+
+export class ModuleScope extends Scope {
+    constructor(scopeManager, upperScope, block) {
+        super(scopeManager, 'module', upperScope, block, false);
+    }
+}
+
+export class FunctionExpressionNameScope extends Scope {
+    constructor(scopeManager, upperScope, block) {
+        super(scopeManager, 'function-expression-name', upperScope, block, false);
+        this.__define(block.id,
+                new Definition(
+                    Variable.FunctionName,
+                    block.id,
+                    block,
+                    null,
+                    null,
+                    null
+                ));
+        this.functionExpressionScope = true;
+    }
+}
+
+export class CatchScope extends Scope {
+    constructor(scopeManager, upperScope, block) {
+        super(scopeManager, 'catch', upperScope, block, false);
+    }
+}
+
+export class WithScope extends Scope {
+    constructor(scopeManager, upperScope, block) {
+        super(scopeManager, 'with', upperScope, block, false);
+    }
+
+    __close(scopeManager) {
+        if (this.__shouldStaticallyClose(scopeManager)) {
+            return super.__close(scopeManager);
+        }
+
+        for (let i = 0, iz = this.__left.length; i < iz; ++i) {
+            let ref = this.__left[i];
+            ref.tainted = true;
+            this.__delegateToUpperScope(ref);
+        }
+        this.__left = null;
+
+        return this.upper;
+    }
+}
+
+export class TDZScope extends Scope {
+    constructor(scopeManager, upperScope, block) {
+        super(scopeManager, 'TDZ', upperScope, block, false);
+    }
+}
+
+export class BlockScope extends Scope {
+    constructor(scopeManager, upperScope, block) {
+        super(scopeManager, 'block', upperScope, block, false);
+    }
+}
+
+export class SwitchScope extends Scope {
+    constructor(scopeManager, upperScope, block) {
+        super(scopeManager, 'switch', upperScope, block, false);
+    }
+}
+
+export class FunctionScope extends Scope {
+    constructor(scopeManager, upperScope, block, isMethodDefinition) {
+        super(scopeManager, 'function', upperScope, block, isMethodDefinition);
+
+        // section 9.2.13, FunctionDeclarationInstantiation.
+        // NOTE Arrow functions never have an arguments objects.
+        if (this.block.type !== Syntax.ArrowFunctionExpression) {
+            this.__defineArguments();
+        }
+    }
+
+    isArgumentsMaterialized() {
+        // TODO(Constellation)
+        // We can more aggressive on this condition like this.
+        //
+        // function t() {
+        //     // arguments of t is always hidden.
+        //     function arguments() {
+        //     }
+        // }
+        if (this.block.type === Syntax.ArrowFunctionExpression) {
+            return false;
+        }
+
+        if (!this.isStatic()) {
+            return true;
+        }
+
+        let variable = this.set.get('arguments');
+        assert(variable, 'Always have arguments variable.');
+        return variable.tainted || variable.references.length  !== 0;
+    }
+
+    isThisMaterialized() {
+        if (!this.isStatic()) {
+            return true;
+        }
+        return this.thisFound;
+    }
+
+    __defineArguments() {
+        this.__defineGeneric(
+                'arguments',
+                this.set,
+                this.variables,
+                null,
+                null);
+        this.taints.set('arguments', true);
+    }
+}
+
+export class ForScope extends Scope {
+    constructor(scopeManager, upperScope, block) {
+        super(scopeManager, 'for', upperScope, block, false);
+    }
+}
+
+export class ClassScope extends Scope {
+    constructor(scopeManager, upperScope, block) {
+        super(scopeManager, 'class', upperScope, block, false);
+    }
+}
+
+/* vim: set sw=4 ts=4 et tw=80 : */
diff --git a/node_modules/escope/src/variable.js b/node_modules/escope/src/variable.js
new file mode 100644
index 000000000..3945b380b
--- /dev/null
+++ b/node_modules/escope/src/variable.js
@@ -0,0 +1,81 @@
+/*
+  Copyright (C) 2015 Yusuke Suzuki <utatane.tea@gmail.com>
+
+  Redistribution and use in source and binary forms, with or without
+  modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+
+  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+  ARE DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+  DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/**
+ * A Variable represents a locally scoped identifier. These include arguments to
+ * functions.
+ * @class Variable
+ */
+export default class Variable {
+    constructor(name, scope) {
+        /**
+         * The variable name, as given in the source code.
+         * @member {String} Variable#name
+         */
+        this.name = name;
+        /**
+         * List of defining occurrences of this variable (like in 'var ...'
+         * statements or as parameter), as AST nodes.
+         * @member {esprima.Identifier[]} Variable#identifiers
+         */
+        this.identifiers = [];
+        /**
+         * List of {@link Reference|references} of this variable (excluding parameter entries)
+         * in its defining scope and all nested scopes. For defining
+         * occurrences only see {@link Variable#defs}.
+         * @member {Reference[]} Variable#references
+         */
+        this.references = [];
+
+        /**
+         * List of defining occurrences of this variable (like in 'var ...'
+         * statements or as parameter), as custom objects.
+         * @member {Definition[]} Variable#defs
+         */
+        this.defs = [];
+
+        this.tainted = false;
+        /**
+         * Whether this is a stack variable.
+         * @member {boolean} Variable#stack
+         */
+        this.stack = true;
+        /**
+         * Reference to the enclosing Scope.
+         * @member {Scope} Variable#scope
+         */
+        this.scope = scope;
+    }
+}
+
+Variable.CatchClause = 'CatchClause';
+Variable.Parameter = 'Parameter';
+Variable.FunctionName = 'FunctionName';
+Variable.ClassName = 'ClassName';
+Variable.Variable = 'Variable';
+Variable.ImportBinding = 'ImportBinding';
+Variable.TDZ = 'TDZ';
+Variable.ImplicitGlobalVariable = 'ImplicitGlobalVariable';
+
+/* vim: set sw=4 ts=4 et tw=80 : */