Fix regression in JSON serialization of RegExps.

Fix regression in JSON serialization of RegExps. 
Tweaks to the serialization.

[Rico, 2010-12-15 07:46:10]

http://codereview.chromium.org/5676005/diff/1/src/date.js
File src/date.js (right):

http://codereview.chromium.org/5676005/diff/1/src/date.js#newcode989
src/date.js:989: ':' + PadInt(this.getUTCMinutes(), 2) + ':' +
PadInt(this.getUTCSeconds(), 2) +
Not your change, but while we are here, there is a long line here

http://codereview.chromium.org/5676005/diff/1/src/date.js#newcode1003
src/date.js:1003: return CheckJSONPrimitive(this.toISOString());
Two things;
1. If "this" is a custom object, and it has a toISOString method that returns an
object this will throw an error, but it should not. It should only throw an
error if there is no toISOString method.

2. If you agree to the above and change the error message we should delete the
TypeError result_not_primitive since this is the only callsite. Also, we can
delete CheckJSONPrimitive since this is the only place we use it.

http://codereview.chromium.org/5676005/diff/1/test/mjsunit/json.js
File test/mjsunit/json.js (right):

http://codereview.chromium.org/5676005/diff/1/test/mjsunit/json.js#newcode368
test/mjsunit/json.js:368: assertEquals('[37,null,1,"foo","37","true",null,"has
toJSON",null,"has toJSON"]',
Long line + space after every comma

http://codereview.chromium.org/5676005/diff/1/test/mjsunit/json.js#newcode400
test/mjsunit/json.js:400: assertEquals('"42"', JSON.stringify(falseNum));
We should also test the case where toJSON is set as a method on an object with a
toISOSting method

[Lasse Reichstein, 2010-12-15 08:59:54]

Please re^2view Date toJSON.

http://codereview.chromium.org/5676005/diff/1/src/date.js
File src/date.js (right):

http://codereview.chromium.org/5676005/diff/1/src/date.js#newcode989
src/date.js:989: ':' + PadInt(this.getUTCMinutes(), 2) + ':' +
PadInt(this.getUTCSeconds(), 2) +
Done.

http://codereview.chromium.org/5676005/diff/1/src/date.js#newcode1003
src/date.js:1003: return CheckJSONPrimitive(this.toISOString());
Rewritten completely, CheckJSONPrimitive removed and result_not_primitive error
message deleted.

http://codereview.chromium.org/5676005/diff/1/test/mjsunit/json.js
File test/mjsunit/json.js (right):

http://codereview.chromium.org/5676005/diff/1/test/mjsunit/json.js#newcode368
test/mjsunit/json.js:368: assertEquals('[37,null,1,"foo","37","true",null,"has
toJSON",null,"has toJSON"]',
It's a string literal, and the exact output of JSON.stringify, so there's not
much to do about the spacing.
Will wrap to avoid line > 80.

http://codereview.chromium.org/5676005/diff/1/test/mjsunit/json.js#newcode400
test/mjsunit/json.js:400: assertEquals('"42"', JSON.stringify(falseNum));
Adding tests of Date.prototype.toJSON when called as generic function.

[Rico, 2010-12-15 09:17:04]

LGTM with test added. I guess the test should succeed because calling the method
will throw the correct error.

http://codereview.chromium.org/5676005/diff/6001/test/mjsunit/json.js
File test/mjsunit/json.js (right):

http://codereview.chromium.org/5676005/diff/6001/test/mjsunit/json.js#newcode81
test/mjsunit/json.js:81: 
Add a test that we throw an exception if we have a toISOString that is not
callable, e.g.:
var d7 = {toJSON: Date.prototype.toJSON,
          valueOf: function() { return 42;},
          ISOString: 42};
assertThrows(d7.toJSON());

[Lasse Reichstein, 2010-12-15 09:29:40]

http://codereview.chromium.org/5676005/diff/6001/test/mjsunit/json.js
File test/mjsunit/json.js (right):

http://codereview.chromium.org/5676005/diff/6001/test/mjsunit/json.js#newcode81
test/mjsunit/json.js:81: 
Added test:

var d7 = {toJSON: Date.prototype.toJSON,
          ISOString: "not callable"};
assertThrows("d7.toJSON()", TypeError);