/* * The contents of this file are subject to the Netscape Public * License Version 1.1 (the "License"); you may not use this file * except in compliance with the License. You may obtain a copy of * the License at http://www.mozilla.org/NPL/ * * Software distributed under the License is distributed on an "AS * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or * implied. See the License for the specific language governing * rights and limitations under the License. * * The Original Code is mozilla.org code. * * The Initial Developer of the Original Code is Netscape * Communications Corporation. Portions created by Netscape are * Copyright (C) 1998 Netscape Communications Corporation. All * Rights Reserved. * * Contributor(s): pschwartau@netscape.com, rogerl@netscape.com * Date: 28 May 2001 * * SUMMARY: Functions are scoped statically, not dynamically * * See ECMA Section 10.1.4 Scope Chain and Identifier Resolution * (This section defines the scope chain of an execution context) * * See ECMA Section 12.10 The with Statement * * See ECMA Section 13 Function Definition * (This section defines the scope chain of a function object as that * of the running execution context when the function was declared) * * Like scope-001.js, but using assignment var f = function expression * instead of a function declaration: function f() {} etc. */ //------------------------------------------------------------------------------------------------- var UBound = 0; var bug = '(none)'; var summary = 'Testing that functions are scoped statically, not dynamically'; var self = this; // capture a reference to the global object var status = ''; var statusitems = [ ]; var actual = ''; var actualvalues = [ ]; var expect= ''; var expectedvalues = [ ]; /* * In this section the expected value is 1, not 2. * * Why? f captures its scope chain from when it's declared, and imposes that chain * when it's executed. In other words, f's scope chain is from when it was compiled. * Since f is a top-level function, this is the global object only. Hence 'a' resolves to 1. */ status = 'Section A of test'; var a = 1; var f = function () {return a;}; var obj = {a:2}; with (obj) { actual = f(); } expect = 1; addThis(); /* * In this section the expected value is 2, not 1. That is because here * f's associated scope chain now includes 'obj' before the global object. */ status = 'Section B of test'; var a = 1; var obj = {a:2}; with (obj) { var f = function () {return a;}; actual = f(); } expect = 2; addThis(); /* * Like Section B , except that we call f outside the with block. * By the principles explained above, we still expect 2 - */ status = 'Section C of test'; var a = 1; var obj = {a:2}; with (obj) { var f = function () {return a;}; } actual = f(); expect = 2; addThis(); /* * Like Section C, but with one more level of indirection - */ status = 'Section D of test'; var a = 1; var obj = {a:2, obj:{a:3}}; with (obj) { with (obj) { var f = function () {return a;}; } } actual = f(); expect = 3; addThis(); /* * Like Section C, but here we actually delete obj before calling f. * We still expect 2 - */ status = 'Section E of test'; var a = 1; var obj = {a:2}; with (obj) { var f = function () {return a;}; } delete obj; actual = f(); expect = 2; addThis(); /* * Like Section E. Here we redefine obj and call f under with (obj) - * We still expect 2 - */ status = 'Section F of test'; var a = 1; var obj = {a:2}; with (obj) { var f = function () {return a;}; } delete obj; var obj = {a:3}; with (obj) { actual = f(); } expect = 2; // NOT 3 !!! addThis(); /* * Explicitly verify that f exists at global level, even though * it was defined under the with(obj) block - */ status = 'Section G of test'; var a = 1; var obj = {a:2}; with (obj) { var f = function () {return a;}; } actual = String([obj.hasOwnProperty('f'), self.hasOwnProperty('f')]); expect = String([false, true]); addThis(); /* * Explicitly verify that f exists at global level, even though * it was defined under the with(obj) block - */ status = 'Section H of test'; var a = 1; var obj = {a:2}; with (obj) { var f = function () {return a;}; } actual = String(['f' in obj, 'f' in self]); expect = String([false, true]); addThis(); //------------------------------------------------------------------------------------------------- test(); //------------------------------------------------------------------------------------------------- function addThis() { statusitems[UBound] = status; actualvalues[UBound] = actual; expectedvalues[UBound] = expect; UBound++; resetTestVars(); } function resetTestVars() { delete a; delete obj; delete f; } function test() { enterFunc ('test'); printBugNumber (bug); printStatus (summary); for (var i = 0; i < UBound; i++) { reportCompare(expectedvalues[i], actualvalues[i], statusitems[i]); } exitFunc ('test'); }