add hw2

node_modules/esutils/lib/ast.js

@@ -0,0 +1,144 @@
+/*
+  Copyright (C) 2013 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.
+*/
+
+(function () {
+    'use strict';
+
+    function isExpression(node) {
+        if (node == null) { return false; }
+        switch (node.type) {
+            case 'ArrayExpression':
+            case 'AssignmentExpression':
+            case 'BinaryExpression':
+            case 'CallExpression':
+            case 'ConditionalExpression':
+            case 'FunctionExpression':
+            case 'Identifier':
+            case 'Literal':
+            case 'LogicalExpression':
+            case 'MemberExpression':
+            case 'NewExpression':
+            case 'ObjectExpression':
+            case 'SequenceExpression':
+            case 'ThisExpression':
+            case 'UnaryExpression':
+            case 'UpdateExpression':
+                return true;
+        }
+        return false;
+    }
+
+    function isIterationStatement(node) {
+        if (node == null) { return false; }
+        switch (node.type) {
+            case 'DoWhileStatement':
+            case 'ForInStatement':
+            case 'ForStatement':
+            case 'WhileStatement':
+                return true;
+        }
+        return false;
+    }
+
+    function isStatement(node) {
+        if (node == null) { return false; }
+        switch (node.type) {
+            case 'BlockStatement':
+            case 'BreakStatement':
+            case 'ContinueStatement':
+            case 'DebuggerStatement':
+            case 'DoWhileStatement':
+            case 'EmptyStatement':
+            case 'ExpressionStatement':
+            case 'ForInStatement':
+            case 'ForStatement':
+            case 'IfStatement':
+            case 'LabeledStatement':
+            case 'ReturnStatement':
+            case 'SwitchStatement':
+            case 'ThrowStatement':
+            case 'TryStatement':
+            case 'VariableDeclaration':
+            case 'WhileStatement':
+            case 'WithStatement':
+                return true;
+        }
+        return false;
+    }
+
+    function isSourceElement(node) {
+      return isStatement(node) || node != null && node.type === 'FunctionDeclaration';
+    }
+
+    function trailingStatement(node) {
+        switch (node.type) {
+        case 'IfStatement':
+            if (node.alternate != null) {
+                return node.alternate;
+            }
+            return node.consequent;
+
+        case 'LabeledStatement':
+        case 'ForStatement':
+        case 'ForInStatement':
+        case 'WhileStatement':
+        case 'WithStatement':
+            return node.body;
+        }
+        return null;
+    }
+
+    function isProblematicIfStatement(node) {
+        var current;
+
+        if (node.type !== 'IfStatement') {
+            return false;
+        }
+        if (node.alternate == null) {
+            return false;
+        }
+        current = node.consequent;
+        do {
+            if (current.type === 'IfStatement') {
+                if (current.alternate == null)  {
+                    return true;
+                }
+            }
+            current = trailingStatement(current);
+        } while (current);
+
+        return false;
+    }
+
+    module.exports = {
+        isExpression: isExpression,
+        isStatement: isStatement,
+        isIterationStatement: isIterationStatement,
+        isSourceElement: isSourceElement,
+        isProblematicIfStatement: isProblematicIfStatement,
+
+        trailingStatement: trailingStatement
+    };
+}());
+/* vim: set sw=4 ts=4 et tw=80 : */