| /* 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 Communicator client code, released March |
| * 31, 1998. |
| * |
| * 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): |
| * |
| */ |
| /** |
| File Name: 12.10-1.js |
| ECMA Section: 12.10 The with statement |
| Description: |
| WithStatement : |
| with ( Expression ) Statement |
| |
| The with statement adds a computed object to the front of the scope chain |
| of the current execution context, then executes a statement with this |
| augmented scope chain, then restores the scope chain. |
| |
| Semantics |
| |
| The production WithStatement : with ( Expression ) Statement is evaluated |
| as follows: |
| 1. Evaluate Expression. |
| 2. Call GetValue(Result(1)). |
| 3. Call ToObject(Result(2)). |
| 4. Add Result(3) to the front of the scope chain. |
| 5. Evaluate Statement using the augmented scope chain from step 4. |
| 6. Remove Result(3) from the front of the scope chain. |
| 7. Return Result(5). |
| |
| Discussion |
| Note that no matter how control leaves the embedded Statement, whether |
| normally or by some form of abrupt completion, the scope chain is always |
| restored to its former state. |
| |
| Author: christine@netscape.com |
| Date: 12 november 1997 |
| */ |
| |
| var SECTION = "12.10-1"; |
| var VERSION = "ECMA_1"; |
| startTest(); |
| var TITLE = "The with statment"; |
| |
| writeHeaderToLog( SECTION + " "+ TITLE); |
| |
| var testcases = getTestCases(); |
| |
| test(); |
| |
| function test() { |
| for ( tc=0; tc < testcases.length; tc++ ) { |
| testcases[tc].passed = writeTestCaseResult( |
| testcases[tc].expect, |
| testcases[tc].actual, |
| testcases[tc].description +" = "+ |
| testcases[tc].actual ); |
| |
| testcases[tc].reason += ( testcases[tc].passed ) ? "" : "wrong value "; |
| } |
| stopTest(); |
| return ( testcases ); |
| } |
| function getTestCases() { |
| var array = new Array(); |
| var item = 0; |
| |
| // although the scope chain changes, the this value is immutable for a given |
| // execution context. |
| |
| array[item++] = new TestCase( SECTION, |
| "with( new Number() ) { this +'' }", |
| "[object global]", |
| eval("with( new Number() ) { this +'' }") ); |
| |
| // the object's functions and properties should override those of the |
| // global object. |
| |
| array[item++] = new TestCase( |
| SECTION, |
| "var MYOB = new WithObject(true); with (MYOB) { parseInt() }", |
| true, |
| eval("var MYOB = new WithObject(true); with (MYOB) { parseInt() }") ); |
| |
| array[item++] = new TestCase( |
| SECTION, |
| "var MYOB = new WithObject(false); with (MYOB) { NaN }", |
| false, |
| eval("var MYOB = new WithObject(false); with (MYOB) { NaN }") ); |
| |
| array[item++] = new TestCase( |
| SECTION, |
| "var MYOB = new WithObject(NaN); with (MYOB) { Infinity }", |
| Number.NaN, |
| eval("var MYOB = new WithObject(NaN); with (MYOB) { Infinity }") ); |
| |
| array[item++] = new TestCase( |
| SECTION, |
| "var MYOB = new WithObject(false); with (MYOB) { }; Infinity", |
| Number.POSITIVE_INFINITY, |
| eval("var MYOB = new WithObject(false); with (MYOB) { }; Infinity") ); |
| |
| |
| array[item++] = new TestCase( |
| SECTION, |
| "var MYOB = new WithObject(0); with (MYOB) { delete Infinity; Infinity }", |
| Number.POSITIVE_INFINITY, |
| eval("var MYOB = new WithObject(0); with (MYOB) { delete Infinity; Infinity }") ); |
| |
| // let us leave the with block via a break. |
| |
| array[item++] = new TestCase( |
| SECTION, |
| "var MYOB = new WithObject(0); while (true) { with (MYOB) { Infinity; break; } } Infinity", |
| Number.POSITIVE_INFINITY, |
| eval("var MYOB = new WithObject(0); while (true) { with (MYOB) { Infinity; break; } } Infinity") ); |
| |
| return ( array ); |
| } |
| function WithObject( value ) { |
| this.prop1 = 1; |
| this.prop2 = new Boolean(true); |
| this.prop3 = "a string"; |
| this.value = value; |
| |
| // now we will override global functions |
| |
| this.parseInt = new Function( "return this.value" ); |
| this.NaN = value; |
| this.Infinity = value; |
| this.unescape = new Function( "return this.value" ); |
| this.escape = new Function( "return this.value" ); |
| this.eval = new Function( "return this.value" ); |
| this.parseFloat = new Function( "return this.value" ); |
| this.isNaN = new Function( "return this.value" ); |
| this.isFinite = new Function( "return this.value" ); |
| } |