Logic Evaluator in c# (Evaluate Logical (&& ,|| ) expressions)

Question

In my project there is a Logic evaluation section, it take input as a string which contains logical expressions (true/false) .

I want to evaluate this string and return a final Boolean value.

string Logic="1&0|1&(0&1)"
//string Logic="true AND false OR true AND (false AND true)"

This will be my Logic. The length might increase.

Is there any way to Evaluate this expression from LINQ / Dynamic LINQ ?

Any reason you're using a single bitwise AND but a short-circuiting logical OR in the example? — Kieren Johnstone, Dec 13 '11 at 08:21
@ Kieren Johnstone : Oh sorry .. nothing like that... I will edit it.. :) — Sreekumar P, Dec 13 '11 at 12:03
If it is okay to use a librarie take a look [here](https://github.com/Genfood/Proviant). — Genfood, Apr 04 '19 at 19:39

fixagon · Accepted Answer · 2011-12-12T15:47:05.917

15

a way without any third party libraries is to use a DataTable with expression.

There you have even the possibility to evaluate on other result value types than just boolean.

System.Data.DataTable table = new System.Data.DataTable();
table.Columns.Add("", typeof(Boolean));
table.Columns[0].Expression = "true and false or true";

System.Data.DataRow r = table.NewRow();
table.Rows.Add(r);
Boolean result = (Boolean)r[0];

the expression syntax is not identical with your example but it does the same thing. An advantage is that its 100% .NET framework contained --> Microsoft managed. The error handling is not bad neither. Exceptions for missing operators etc...

available operators

edited Dec 12 '11 at 15:47

answered Dec 12 '11 at 15:28

fixagon

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but this is taking 7 milli seconds... my existing code takes less than 1 milli sec.... i want to reduce this – Sreekumar P Dec 12 '11 at 15:53
i dont think its the most performant option... but has quite some possibilities – fixagon Dec 12 '11 at 15:55

score 12 · Answer 2 · edited May 21 '20 at 15:05

12

This is even shorter than the solution given by @fixagon:

System.Data.DataTable table = new System.Data.DataTable();
bool result = (bool)table.Compute("true and false or true", "");

True, False, Not operators, as well as parentheses are allowed.

edited May 21 '20 at 15:05

mystith myst

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answered Jul 20 '19 at 09:13

DataGuy

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Works for me (upvote). As an addition: also parentheses are allowed in order to change precedence. – Teodor Tite Sep 26 '19 at 11:15

Logic Evaluator in c# (Evaluate Logical (&& ,|| ) expressions)

2 Answers2

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