public void BindRightIdentity()
{
// m >>= return == m
var m = EitherString.Return(5);
Assert.That(m.Bind(EitherString.Return), Is.EqualTo(m));
}
public void BindLeftIdentity()
{
// (return x) >>= f == f x
const int x = 5;
Func <int, Either <string, int> > f = n => EitherString.Right(n * n);
Assert.That(EitherString.Return(x).Bind(f), Is.EqualTo(f(x)));
}
public void BindAssociativity()
{
// (m >>= f) >>= g == m >>= (\x -> f x >>= g)
Func <int, Either <string, int> > f = n => EitherString.Right(n * n);
Func <int, Either <string, string> > g = n => EitherString.Right(Convert.ToString(n));
var m = EitherString.Return(5);
Assert.That(m.Bind(f).Bind(g), Is.EqualTo(m.Bind(x => f(x).Bind(g))));
}