Extend testing of argument definition test expressions.

dart/tests/language/argument_definition_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 // Dart test program for testing argument definition test.
 
-int test(int a, [int b, int c]) {
+int test(int a, [int b = 2, int c = 3]) {
   int result = 0;
   ?b;
   ?result;  /// 01: compile-time error
   if (?a) {
     result += 100;
   }
   if (?b) {
     result += 20;
   }
   if (?c) {
     var b; ?b;  /// 02: compile-time error
     result += 3;
   }
+  if ((!?a?!?b:!?c) == (?a??b:?c)) {
+    result += 200;
+  }
+  if (!?a?!?b:!?c == ?a??b:?c) {
+    result += 400;
+  }
   return result;
 }
 
-closure_test(int a, [int b, int c]) {
+closure_test(int a, [int b = 2, int c = 3]) {
   var x = 0;
   return () {
     int result = 0;
     ?b;
     ?result;  /// 03: compile-time error
     ?x;  /// 04: compile-time error
     if (?a) {
       result += 100;
     }
     if (?b) {
       result += 20;
     }
     if (?c) {
       var b; ?b;  /// 05: compile-time error
       result += 3;
     }
+    // Equivalent to: (!?c) == ?b.
+    if ((!?a?!?b:!?c) == (?a??b:?c)) {
+      result += 200;
+    }
+    // Equivalent to: (!?c) ? ?b : ?c.
+    if (!?a?!?b:!?c == ?a??b:?c) {
+      result += 400;
+    }
     return result;
   };
 }
 
 main() {
   // Use a loop to test optimized version as well.
   for (int i = 0; i < 1000; i++) {
     Expect.equals(100, test(1));
-    Expect.equals(120, test(1, 2));
-    Expect.equals(123, test(1, 2, 3));
-    Expect.equals(103, test(1, c:3));
+    Expect.equals(720, test(1, 2));
+    Expect.equals(523, test(1, 2, 3));
+    Expect.equals(703, test(1, c:3));
 
     Expect.equals(100, closure_test(1)());
-    Expect.equals(120, closure_test(1, 2)());
-    Expect.equals(123, closure_test(1, 2, 3)());
-    Expect.equals(103, closure_test(1, c:3)());
+    Expect.equals(720, closure_test(1, 2)());
+    Expect.equals(523, closure_test(1, 2, 3)());
+    Expect.equals(703, closure_test(1, c:3)());
   }
 }

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

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]

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...