michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: 
michael@0: /**
michael@0:    File Name:          12.10-1.js
michael@0:    ECMA Section:       12.10 The with statement
michael@0:    Description:
michael@0:    WithStatement :
michael@0:    with ( Expression ) Statement
michael@0: 
michael@0:    The with statement adds a computed object to the front of the scope chain
michael@0:    of the current execution context, then executes a statement with this
michael@0:    augmented scope chain, then restores the scope chain.
michael@0: 
michael@0:    Semantics
michael@0: 
michael@0:    The production WithStatement : with ( Expression ) Statement is evaluated
michael@0:    as follows:
michael@0:    1.  Evaluate Expression.
michael@0:    2.  Call GetValue(Result(1)).
michael@0:    3.  Call ToObject(Result(2)).
michael@0:    4.  Add Result(3) to the front of the scope chain.
michael@0:    5.  Evaluate Statement using the augmented scope chain from step 4.
michael@0:    6.  Remove Result(3) from the front of the scope chain.
michael@0:    7.  Return Result(5).
michael@0: 
michael@0:    Discussion
michael@0:    Note that no matter how control leaves the embedded Statement, whether
michael@0:    normally or by some form of abrupt completion, the scope chain is always
michael@0:    restored to its former state.
michael@0: 
michael@0:    Author:             christine@netscape.com
michael@0:    Date:               12 november 1997
michael@0: */
michael@0: 
michael@0: var SECTION = "12.10-1";
michael@0: var VERSION = "ECMA_1";
michael@0: startTest();
michael@0: var TITLE   = "The with statement";
michael@0: 
michael@0: writeHeaderToLog( SECTION + " "+ TITLE);
michael@0: 
michael@0: 
michael@0: // although the scope chain changes, the this value is immutable for a given
michael@0: // execution context.
michael@0: 
michael@0: new TestCase( SECTION,
michael@0: 	      "with( new Number() ) { this +'' }",
michael@0: 	      GLOBAL,
michael@0: 	      eval("with( new Number() ) { this +'' }") );
michael@0: 
michael@0: // the object's functions and properties should override those of the
michael@0: // global object.
michael@0: 
michael@0: new TestCase(
michael@0:   SECTION,
michael@0:   "var MYOB = new WithObject(true); with (MYOB) { parseInt() }",
michael@0:   true,
michael@0:   eval("var MYOB = new WithObject(true); with (MYOB) { parseInt() }") );
michael@0: 
michael@0: new TestCase(
michael@0:   SECTION,
michael@0:   "var MYOB = new WithObject(false); with (MYOB) { NaN }",
michael@0:   false,
michael@0:   eval("var MYOB = new WithObject(false); with (MYOB) { NaN }") );
michael@0: 
michael@0: new TestCase(
michael@0:   SECTION,
michael@0:   "var MYOB = new WithObject(NaN); with (MYOB) { Infinity }",
michael@0:   Number.NaN,
michael@0:   eval("var MYOB = new WithObject(NaN); with (MYOB) { Infinity }") );
michael@0: 
michael@0: new TestCase(
michael@0:   SECTION,
michael@0:   "var MYOB = new WithObject(false); with (MYOB) { }; Infinity",
michael@0:   Number.POSITIVE_INFINITY,
michael@0:   eval("var MYOB = new WithObject(false); with (MYOB) { }; Infinity") );
michael@0: 
michael@0: 
michael@0: new TestCase(
michael@0:   SECTION,
michael@0:   "var MYOB = new WithObject(0); with (MYOB) { delete Infinity; Infinity }",
michael@0:   Number.POSITIVE_INFINITY,
michael@0:   eval("var MYOB = new WithObject(0); with (MYOB) { delete Infinity; Infinity }") );
michael@0: 
michael@0: // let us leave the with block via a break.
michael@0: 
michael@0: new TestCase(
michael@0:   SECTION,
michael@0:   "var MYOB = new WithObject(0); while (true) { with (MYOB) { Infinity; break; } } Infinity",
michael@0:   Number.POSITIVE_INFINITY,
michael@0:   eval("var MYOB = new WithObject(0); while (true) { with (MYOB) { Infinity; break; } } Infinity") );
michael@0: 
michael@0: 
michael@0: test();
michael@0: 
michael@0: function WithObject( value ) {
michael@0:   this.prop1 = 1;
michael@0:   this.prop2 = new Boolean(true);
michael@0:   this.prop3 = "a string";
michael@0:   this.value = value;
michael@0: 
michael@0:   // now we will override global functions
michael@0: 
michael@0:   this.parseInt = new Function( "return this.value" );
michael@0:   this.NaN = value;
michael@0:   this.Infinity = value;
michael@0:   this.unescape = new Function( "return this.value" );
michael@0:   this.escape   = new Function( "return this.value" );
michael@0:   this.eval     = new Function( "return this.value" );
michael@0:   this.parseFloat = new Function( "return this.value" );
michael@0:   this.isNaN      = new Function( "return this.value" );
michael@0:   this.isFinite   = new Function( "return this.value" );
michael@0: }