Question

I have a bunch of code that has lots integers with different meanings (I’d rather a general solution but for a specific example: day-of-the-month vs. month-of-the-year vs. year etc.). I want to be able to overload a class constructor based on these meanings.

For example

int a; // takes role A int b; // takes role B  var A = new Foo(a);  // should call one constructor var B = new Foo(b);  // should call another constructor 

Now clearly that won’t work but if I could define a type (not just an alias) that is an int in all but name like this:

typedef int TypeA;  // stealing the C syntax typedef int TypeB; 

I could do the overloading I need and let the type system keep track of what things are what. In particular this would allow me to be sure that values are not mixed up, for example a value returned from a function as a year is not used as a day-of-the-month.

Is there any way short of class or struct wrappers to do this in c#?

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It would be nice if the solution would also work for floats and doubles.

Answer 1

There is no direct typedef equivalent, but you can do the following:

using TypeA = int; using TypeB = int; 

However, this just aliases the type rather than creating a new strong type. Therefore, the compiler will still treat them as an int when resolving method calls.

A better solution might be to create simple wrapper classes that wraps int and provides implicit casting, such as:

struct TypeA {    public TypeA(int value)    {       this.realValue = value;    }     private int realValue;    public static implicit operator int(TypeA value)    {      return this.realValue;    }     public static implicit operator TypeA(int value)    {      return new TypeA(value);    } } 

However, in most situations, an enum would be more appropriate.