I would like to have a C# method which counts the number of cases in a switch statment. (Let's call it CaseCounter). For example, let's say you have this enum and these two methods:
enum Painter
{
Rubens,
Rembrandt,
Vermeer,
Picasso,
Kandinsky
}
int GetYearOfBirth(Painter painter)
{
switch(painter)
{
case Painter.Kandinsky:
return 1866;
case Painter.Picasso:
return 1881;
case Painter.Rembrandt:
return 1606;
case Painter.Rubens:
return 1577;
case Painter.Vermeer:
return 1632;
default:
return 0;
}
}
bool IsModern(Painter painter)
{
switch (painter)
{
case Painter.Kandinsky:
case Painter.Picasso:
return true;
default:
return false;
}
}
Now the following equalities should hold:
CaseCounter("GetYearOfBirth") == 5
CaseCounter("IsModern") == 2
(It is not important whether or not you include the default case in the count. Also, the parameter to CaseCounter doesn't need to be a string; any type which can somehow be used to represent a method will do.)
So, how would you go about implementing CaseCounter? Is it even possible?
--- ADDENDUM (EDIT) ---
Here's a bit of background info in case you're wondering why I asked this question.
I'm maintaining a code base which contains a lot of methods that switch on enums. The methods are spread across various classes; this makes life difficult when an enum is extended (for example, when you add a new Painter). To make maintenance a little bit easier, I have written some unit tests of the following form:
// If this test fails please check that the following methods are still OK:
// MyClass.GetYearOfBirth, MyOtherClass.IsModernAllCases .
// (There is no guarantee that the above list is up-to-date or complete.)
[Test]
public void PainterCountTest()
{
int numberOfMembers = Enum.GetValues(typeof(NotificationID)).Length;
Assert.AreEqual(5, numberOfMembers);
}
(In this example, IsModernAllCases is just a variation of IsModern which refers explicitly to all 5 possible values of the Painter enum.)
This test is better than nothing, but it's clumsy. It would be a little less clumsy if you could write something like this:
[Test]
public void PainterCountTest()
{
int numberOfMembers = Enum.GetValues(typeof(NotificationID)).Length;
int numberOfCases_getYearOfBirth = CaseCounter("MyClass.GetYearOfBirth");
Assert.AreEqual(numberOfCases_getYearOfBirth, numberOfMembers);
int numberOfCases_modern = CaseCounter("MyOtherClass.IsModernAllCases");
Assert.AreEqual(numberOfCases_modern, numberOfMembers);
}
In this scenario, at least you don't have to modify the unit test when you extend the enum.
