/**********************************************************************************************

* This fiddle is a demo of the library : CodingSeb.ExpressionEvaluator

* See : https://github.com/codingseb/ExpressionEvaluator

* For Others examples : https://dotnetfiddle.net/Packages/41132/CodingSeb_ExpressionEvaluator

**********************************************************************************************/

​

using System;

using System.Text.RegularExpressions;

using System.Collections.Generic;

​

using CodingSeb.ExpressionEvaluator;

​

public class XExpressionEvaluator : ExpressionEvaluator

{

    protected override void Init()

    {

        ParsingMethods.Insert(0, EvaluateDateTimeSyntax);

        ParsingMethods.Add(EvaluateSpecialTernaryOperator);

    }

​

    /// <summary>

    /// To evaluate DateTimes objects with #year-month-day syntax (#2019-05-28)

    /// </summary>

    protected virtual bool EvaluateDateTimeSyntax(string expression, Stack<object> stack, ref int i)

    {

        Match match = Regex.Match(expression.Substring(i), @"^\s*#(?<year>\d{4})-(?<month>\d{2})-(?<day>\d{2})");

​

        if(match.Success)

        {

            int year = int.Parse(match.Groups["year"].Value);

            int month = int.Parse(match.Groups["month"].Value);

            int day = int.Parse(match.Groups["day"].Value);

​

            DateTime dateTime = new DateTime(year,month, day);

​

            stack.Push(dateTime);

​

            i += match.Length - 1;

​

            return true;

        }

​

        return false;

    }

​

    /// <summary>

    /// To evaluate a string replace with custom ternary indicator

    /// </summary>

    protected virtual bool EvaluateSpecialTernaryOperator(string expression, Stack<object> stack, ref int i)

    {

        if (expression.Substring(i, 1).Equals("°"))

        {

            string input = (string)ProcessStack(stack);

​

            string restOfExpression = expression.Substring(i + 1);

​

            for (int j = 0; j < restOfExpression.Length; j++)

            {

                string s2 = restOfExpression.Substring(j, 1);

​

                Match internalStringMatch = stringBeginningRegex.Match(restOfExpression.Substring(j));

​

                if (internalStringMatch.Success)

                {

                    string innerString = internalStringMatch.Value + GetCodeUntilEndOfString(restOfExpression.Substring(j + internalStringMatch.Length), internalStringMatch);

                    j += innerString.Length - 1;

                }

                else if (s2.Equals("("))

                {

                    j++;

                    GetExpressionsBetweenParenthesesOrOtherImbricableBrackets(restOfExpression, ref j, false);

                }

                else if (s2.Equals("@"))

                {

                    stack.Clear();

​

                    stack.Push(input.Replace(Evaluate<string>(restOfExpression.Substring(1, j - 1)), Evaluate<string>(restOfExpression.Substring(j + 1))));

​

                    i = expression.Length;

​

                    return true;

                }

            }

        }

​

        return false;

    }

}

​

public class Program

{

    public static void Main()

    {

        ExpressionEvaluator evaluator = new XExpressionEvaluator();

        List<string> expressions = new List<string>()

        {

            "\"A sentence where a word must be replaced where it is\" ° \"replaced\" @ \"kept\"",

            "#1985-09-11.Year",

            "#1985-09-11.Month",

            "#1985-09-11.Day",

            "#1985-09-11.Equals(new DateTime(1985,9,11))"

        };

        expressions.ForEach(expression => 

        {

            try

            {

                Console.WriteLine(expression);

                Console.WriteLine(evaluator.Evaluate(expression));

            }

            catch(Exception exception)

            {

                Console.WriteLine(exception.Message);

            }

            finally

            {

                Console.WriteLine(string.Empty);    

            }

        });

    }

}