Extend testing of argument definition test expressions.

Extend testing of argument definition test expressions.

Committed: https://code.google.com/p/dart/source/detail?r=11684

[gbracha, 2012-08-31 14:06:21]

Dart code lgtm

[regis, 2012-08-31 14:44:50]

LGTM

Thanks!

https://chromiumcodereview.appspot.com/10916050/diff/1/dart/tests/language/ar...
File dart/tests/language/argument_definition_test.dart (right):

https://chromiumcodereview.appspot.com/10916050/diff/1/dart/tests/language/ar...
dart/tests/language/argument_definition_test.dart:71: }
Matthias wanted me to add this other test yesterday, but I have not figured out
what it does and how to call it :-)

WTF([a, b, c]) {
  Expect.true(!?a??b:!?c == ?a?!?c:?b)
}

[ahe, 2012-08-31 15:08:45]

https://chromiumcodereview.appspot.com/10916050/diff/1/dart/tests/language/ar...
File dart/tests/language/argument_definition_test.dart (right):

https://chromiumcodereview.appspot.com/10916050/diff/1/dart/tests/language/ar...
dart/tests/language/argument_definition_test.dart:71: }
On 2012/08/31 14:44:50, regis wrote:
> Matthias wanted me to add this other test yesterday, but I have not figured
out
> what it does and how to call it :-)
> 
> WTF([a, b, c]) {
>   Expect.true(!?a??b:!?c == ?a?!?c:?b)
> }

So that's the origin. I took it from Gilad's chat status :-)

The problem is that this is not testing exactly what you think. It took me a
while to realize, it groups like this:

(!?a) ? (?b) : (((!?c) == ?a) ? (!?c) : (?b))

So if a is not passed, it tests if b is passed.

If a is passed, then (((!?c) == ?a) ? (!?c) : (?b)) reduces to:

(!?c) ? (!?c) : (?b)

Which is the same as:

(!?c) || (?b)

So if a is passed, then it returns true if c is not passed, or if b is passed.

In summary:

(!?a) ? (?b) : ((!?c) || (?b))

Or:

(?a) ?  ((!?c) || (?b)) : (?b)

Or:

(?b) || ((?a) && (!?c))

Unless I made a mistake above...