12.10-1.js   [plain text]

/* 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" );
}