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/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
* 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)
*/
//-----------------------------------------------------------------------------
var UBound = 0;
var BUGNUMBER = '(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;
function f()
{
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)
{
function f()
{
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)
{
function f()
{
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)
{
function f()
{
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)
{
function f()
{
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)
{
function f()
{
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)
{
function f()
{
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)
{
function f()
{
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(BUGNUMBER);
printStatus (summary);
for (var i = 0; i < UBound; i++)
{
reportCompare(expectedvalues[i], actualvalues[i], statusitems[i]);
}
exitFunc ('test');
}
|
