using System;
using System.Linq.Expressions;


namespace Sample
{
    public class NullableDateTimePredicates
    {
        public static Expression<Func<Nullable<DateTime>, bool>> HasDateValue()
        {
            return f => f.HasValue;
        }

        public static Expression<Func<Nullable<DateTime>, bool>> GreaterThan( DateTime dateToCompareWith )
        {
            return f => f.HasValue && f.Value > dateToCompareWith;
        }

        public static Expression<Func<Nullable<DateTime>, bool>> LessThan(DateTime dateToCompareWith)
        {
            return f => f.HasValue && f.Value < dateToCompareWith;
        }

        public static Expression<Func<Nullable<DateTime>, bool>> Equals(DateTime dateToCompareWith)
        {
            return f => f.HasValue && f.Value == dateToCompareWith;
        }
    }
}