static bool Elem <EqA, A>(A x, A[] ys) where EqA : struct, Eq <A>
{
for (int i = 0; i < ys.Length; i++)
{
if (Overloads.Eq <EqA, A>(x, ys[i]))
{
return(true);
}
}
return(false);
}
/*
* Now every dictionary that implements Ord<A> must implement Eq<A> too, and can be used
* as such when required.
*
* Of course, in CS we have to make Dictionary construction and passing (as types, not values) explicit.
* This is what a modified C# compiler would hopefully be able to do for you,
* just like Haskell does by solving constraints to construct dictionaries at compile time.
*
* The point is that the underlying mechanism for implementing Haskell Type Classes is already there!
*
*/
public static void Run()
{
Console.WriteLine("Find Test {0}", Elem <EqInt, int>(1, new int[] { 1, 2, 3 }));
Console.WriteLine("Find Test {0}", Elem <EqInt, int>(4, new int[] { 1, 2, 3 }));
Console.WriteLine("Equals Test {0}",
Overloads.Eq <EqArray <int[], EqArray <int, EqInt> >, int[][]>(new int[][] { new int[] { 1, 2 }, new int[] { 3, 4 } },
new int[][] { new int[] { 1, 2 }, new int[] { 3, 4 } }));
Console.WriteLine("Equals Test {0}",
Overloads.Eq <EqArray <int[], EqArray <int, EqInt> >, int[][]>(new int[][] { new int[] { 1, 2 }, new int[] { 3, 4 } },
new int[][] { new int[] { 1, 2 }, new int[] { 3, 5 } }));
}
public bool Equals(A[] a, A[] b)
{
if (a == null)
{
return(b == null);
}
if (b == null)
{
return(false);
}
if (a.Length != b.Length)
{
return(false);
}
for (int i = 0; i < a.Length; i++)
{
if (!Overloads.Eq <EqA, A>(a[i], b[i]))
{
return(false);
}
}
return(true);
}