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      1 /*
      2 * The contents of this file are subject to the Netscape Public
      3 * License Version 1.1 (the "License"); you may not use this file
      4 * except in compliance with the License. You may obtain a copy of
      5 * the License at http://www.mozilla.org/NPL/
      6 *
      7 * Software distributed under the License is distributed on an
      8 * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either expressed
      9 * or implied. See the License for the specific language governing
     10 * rights and limitations under the License.
     11 *
     12 * The Original Code is mozilla.org code.
     13 *
     14 * The Initial Developer of the Original Code is Netscape
     15 * Communications Corporation.  Portions created by Netscape are
     16 * Copyright (C) 1998 Netscape Communications Corporation.
     17 * All Rights Reserved.
     18 *
     19 * Contributor(s): pschwartau (at) netscape.com
     20 * Date: 2001-07-13
     21 *
     22 * SUMMARY: Applying Function.prototype.call to the Function object itself
     23 *
     24 *
     25 * ECMA-262 15.3.4.4 Function.prototype.call (thisArg [,arg1 [,arg2,] ] )
     26 *
     27 * When applied to the Function object itself, thisArg should be ignored.
     28 * As explained by Waldemar (waldemar (at) netscape.com):
     29 *
     30 * Function.call(obj, "print(this)") is equivalent to invoking
     31 * Function("print(this)") with this set to obj. Now, Function("print(this)")
     32 * is equivalent to new Function("print(this)") (see 15.3.1.1), and the latter
     33 * ignores the this value that you passed it and constructs a function
     34 * (which we'll call F) which will print the value of the this that will be
     35 * passed in when F will be invoked.
     36 *
     37 * With the last set of () you're invoking F(), which means you're calling it
     38 * with no this value. When you don't provide a this value, it defaults to the
     39 * global object.
     40 *
     41 */
     42 //-----------------------------------------------------------------------------
     43 var UBound = 0;
     44 var bug = '(none)';
     45 var summary = 'Applying Function.prototype.call to the Function object itself';
     46 var status = '';
     47 var statusitems = [];
     48 var actual = '';
     49 var actualvalues = [];
     50 var expect= '';
     51 var expectedvalues = [];
     52 var self = this; // capture a reference to the global object
     53 var cnOBJECT_GLOBAL = self.toString();
     54 var cnOBJECT_OBJECT = (new Object).toString();
     55 var cnHello = 'Hello';
     56 var cnRed = 'red';
     57 var objTEST = {color:cnRed};
     58 var f = new Function();
     59 var g = new Function();
     60 
     61 
     62 f = Function.call(self, 'return cnHello');
     63 g = Function.call(objTEST, 'return cnHello');
     64 
     65 status = 'Section A of test';
     66 actual = f();
     67 expect = cnHello;
     68 captureThis();
     69 
     70 status = 'Section B of test';
     71 actual = g();
     72 expect = cnHello;
     73 captureThis();
     74 
     75 
     76 f = Function.call(self, 'return this.toString()');
     77 g = Function.call(objTEST, 'return this.toString()');
     78 
     79 status = 'Section C of test';
     80 actual = f();
     81 expect = cnOBJECT_GLOBAL;
     82 captureThis();
     83 
     84 status = 'Section D of test';
     85 actual = g();
     86 expect = cnOBJECT_GLOBAL;
     87 captureThis();
     88 
     89 
     90 f = Function.call(self, 'return this.color');
     91 g = Function.call(objTEST, 'return this.color');
     92 
     93 status = 'Section E of test';
     94 actual = f();
     95 expect = undefined;
     96 captureThis();
     97 
     98 status = 'Section F of test';
     99 actual = g();
    100 expect = undefined;
    101 captureThis();
    102 
    103 
    104 
    105 //-----------------------------------------------------------------------------
    106 test();
    107 //-----------------------------------------------------------------------------
    108 
    109 
    110 function captureThis()
    111 {
    112   statusitems[UBound] = status;
    113   actualvalues[UBound] = actual;
    114   expectedvalues[UBound] = expect;
    115   UBound++;
    116 }
    117 
    118 
    119 function test()
    120 {
    121   enterFunc ('test');
    122   printBugNumber (bug);
    123   printStatus (summary);
    124 
    125   for (var i = 0; i < UBound; i++)
    126   {
    127     reportCompare(expectedvalues[i], actualvalues[i], statusitems[i]);
    128   }
    129 
    130   exitFunc ('test');
    131 }
    132