third_party/WebKit/LayoutTests/fast/js/eval-keyword-vs-function.html

   1 <p>
   2 This page verifies that eval has two meanings:
   3 <ol>
   4     <li>An operator: executes a script in local scope with the local scope's variable object and "this" object.</li>
   5     <li>A global function: executes a script in global scope with the global scope's variable object and "this" object.</li>
   6 </ol>
   7 Meaning #2 should remain constant even if the global eval function is copied
   8 into a global variable ("globalEval") or a local variable ("localEval").
   9 </p>
  10 <p>If the test passes, you'll see a series of pass messages below.</p>
  11 <hr>
  12 <pre id="console"></pre>
  13
  14 <script>
  15 if (window.testRunner)
  16     testRunner.dumpAsText();
  17
  18 var globalEval = eval;
  19
  20 function log(s)
  21 {
  22     document.getElementById("console").appendChild(document.createTextNode(s + "\n"));
  23 }
  24
  25 function shouldBe(aDescription, a, b)
  26 {
  27     if (a === b) {
  28         log("PASS: " + aDescription + " should be " + b + " and is.");
  29     } else {
  30         log("FAIL: " + aDescription + " should be " + b + " but instead is " + a + ".");
  31     }
  32 }
  33
  34 function testGetX()
  35 {
  36     var x = 1;
  37     var localEval = window.eval;
  38
  39     window.x = 0;
  40
  41     shouldBe('eval("x")', eval("x"), 1);
  42
  43     shouldBe('window.eval("x")', window.eval("x"), 0);
  44     shouldBe('globalEval("x")', globalEval("x"), 0);
  45     shouldBe('localEval("x")', localEval("x"), 0);
  46
  47     // Per ES5 15.1.2.11 & 10.2.2.1 any reference that hits an enviromment record (i.e. does not have a base)
  48     // and has a reference name of "eval" is treated as a direct eval - the assignment to a var makes no difference.
  49     shouldBe('(function() { var eval = window.eval; return eval("x"); })()', (function() { var eval = window.eval; return eval("x"); })(), 1);
  50 }
  51
  52 function testVarY()
  53 {
  54     var localEval = window.eval;
  55
  56     shouldBe('eval("var y; \"y\" in window")', eval("var y; \"y\" in window"), false);
  57     delete window.y;
  58
  59     shouldBe('window.eval("var y; \"y\" in window")', window.eval("var y; \"y\" in window"), true);
  60     delete window.y;
  61
  62     shouldBe('globalEval("var y; \"y\" in window")', globalEval("var y; \"y\" in window"), true);
  63     delete window.y;
  64
  65     shouldBe('localEval("var y; \"y\" in window")', localEval("var y; \"y\" in window"), true);
  66     delete window.y;
  67
  68     // Per ES5 15.1.2.11 & 10.2.2.1 any reference that hits an enviromment record (i.e. does not have a base)
  69     // and has a reference name of "eval" is treated as a direct eval - the assignment to a var makes no difference.
  70     shouldBe('(function() { var eval = window.eval; return eval("var y; \"y\" in window"); })()', (function() { var eval = window.eval; return eval("var y; \"y\" in window"); })(), false);
  71 }
  72
  73 function testSetZ()
  74 {
  75     var z = 0;
  76     window.z = 0;
  77     var localEval = window.eval;
  78
  79     shouldBe('eval("z = 1; window.z")', eval("z = 1; window.z"), 0);
  80
  81     shouldBe('window.eval("z = 2; window.z")', window.eval("z = 2; window.z"), 2);
  82
  83     shouldBe('globalEval("z = 3; window.z")', globalEval("z = 3; window.z"), 3);
  84
  85     shouldBe('localEval("z = 4; window.z")', localEval("z = 4; window.z"), 4);
  86
  87     // Per ES5 15.1.2.11 & 10.2.2.1 any reference that hits an enviromment record (i.e. does not have a base)
  88     // and has a reference name of "eval" is treated as a direct eval - the assignment to a var makes no difference.
  89     shouldBe('(function() { var eval = window.eval; return eval("z = 5; window.z"); })()', (function() { var eval = window.eval; return eval("z = 5; window.z"); })(), 4);
  90 }
  91
  92 function testThis()
  93 {
  94     var localEval = window.eval;
  95
  96     shouldBe('eval("this")', eval("this"), this);
  97     shouldBe('window.eval("this")', window.eval("this"), window);
  98     shouldBe('globalEval("this")', globalEval("this"), window);
  99     shouldBe('localEval("this")', localEval("this"), window);
 100     shouldBe('(function() { var eval = window.eval; return eval("this"); })()', (function() { var eval = window.eval; return eval("this"); })(), window);
 101 }
 102
 103 log("\n----- Scope Chain for Getters: -----\n");
 104 testGetX();
 105 log("\n----- Variable Object: -----\n");
 106 testVarY();
 107 log("\n----- Scope Chain for Setters: -----\n");
 108 testSetZ();
 109 log("\n----- This Object: -----\n");
 110 testThis.call({ toString: function() { return "[\"this\" object passed to .call()]"; } });
 111 </script>