Basic Logical Operations with LINQ Expressions

How to implement basic logical operations (AND, OR, NOT, XOR) with LINQ expressions:

 1 public static class ExpressionExtensions

 2     {

 3         public static Expression<Func<T, Boolean>> Or<T>(this Expression<Func<T, Boolean>> expr, Expression<Func<T, Boolean>> other)

 4         {

 5             InvocationExpression invokedExpr = Expression.Invoke(other, expr.Parameters.Cast<Expression>());

 6             return (Expression.Lambda<Func<T, Boolean>>(Expression.OrElse(expr.Body, invokedExpr), expr.Parameters));

 7         }

 8 

 9         public static Expression<Func<T, Boolean>> Xor<T>(this Expression<Func<T, Boolean>> expr, Expression<Func<T, Boolean>> other)

         {

             InvocationExpression invokedExpr = Expression.Invoke(other, expr.Parameters.Cast<Expression>());

             return (Expression.Lambda<Func<T, Boolean>>(Expression.ExclusiveOr(expr.Body, invokedExpr), expr.Parameters));

         }

 

         public static Expression<Func<T, Boolean>> Not<T>(this Expression<Func<T, Boolean>> expr)

         {

             return (Expression.Lambda<Func<T, Boolean>>(Expression.Not(expr.Body), expr.Parameters));

         }

 

         public static Expression<Func<T, Boolean>> And<T>(this Expression<Func<T, Boolean>> expr, Expression<Func<T, Boolean>> other)

         {

             InvocationExpression invokedExpr = Expression.Invoke(other, expr.Parameters.Cast<Expression>());

             return (Expression.Lambda<Func<T, Boolean>>(Expression.AndAlso(expr.Body, invokedExpr), expr.Parameters));

         }

     }  

 

Usages: 

Expression<Func<int, bool>> isEven = i => (i % 2) == 0;

Expression<Func<int, bool>> isMultipleOfFive => i => (i % 5) == 0;

Expression<Func<int, bool>> evenOrMultipleOfFive = isEven.Or(isMultipleOfFive);

Expression<Func<int, bool>> isOdd = isEven.Not();

And so on.