ResultComparison<T> 'monad'

PreResultComparisonInvocation.cs

string val;

int comp = Comparer<int>.Default.Compare (0, 1);
if (comp > 0)
    val = "greater than";
else if (comp < 0)
    val = "less than";
else
    val = "equal";

ResultComparison.cs

public static class Comparison
{
    public static ResultComparison<TResult> ToComparison<TSource, TResult> (this IComparer<TSource> comparer, TSource, x, TSource y)
    {
         if (comparer == null) throw new ArgumentNullException ("comparer");

         return new ResultComparison<TResult> (comparer.Compare (x, y));
    }
}

public class ResultComparison<T>
{
    T Result
    {
        get;
        private set;
    }

    int _comparison;

    public ResultComparison<T> Equal (Func<T> func)
    {
        if (_comparison == 0)
            Result = func ();

        return this;
    }

    public ResultComparison<T> LessThan (Func<T> func)
    {
        if (_comparison < 0)
            Result = func ();

        return this;
    }

    public ResultComparison<T> GreaterThan (Func<T> func)
    {
        if (_comparison > 0)
            Result = func ();

        return this;
    }

    public ResultComparison (int comparison)
    {
        _comparison = comparison;
    }
}

ResultComparisonInvocation.cs

string val = Comparer<int>.Default
    .ToComparison<int, string> (0, 1))
    .GreaterThan (() => "greater than")
    .LessThan    (() => "less than")
    .Equal       (() => "equal")
    .Result;