using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Linq.Expressions;

namespace AddWhere
{
    public static class PredicateExtensions
    {

        public static Expression<Func<T, bool>> True<T>() { return f => true; }
        public static Expression<Func<T, bool>> False<T>() { return f => false; }

        public static Expression<Func<T, bool>> Or<T>(this Expression<Func<T, bool>> expression1,
        Expression<Func<T, bool>> expression2)
        {

            var invokedExpression = Expression.Invoke(expression2, expression1.Parameters.Cast<Expression>());

            return Expression.Lambda<Func<T, bool>>

            (Expression.Or(expression1.Body, invokedExpression), expression1.Parameters);
        }



        public static Expression<Func<T, bool>> And<T>(this Expression<Func<T, bool>> expression1,
        Expression<Func<T, bool>> expression2)
        {

            var invokedExpression = Expression.Invoke(expression2, expression1.Parameters.Cast<Expression>());

            return Expression.Lambda<Func<T, bool>>

            (Expression.And(expression1.Body, invokedExpression), expression1.Parameters);

        }

    }

}