index.md

Intro

NCalc is a mathematical expression evaluator in .NET. NCalc can parse any expression and evaluate the result, including static or dynamic parameters and custom functions.

Project Description

NCalc is a mathematical expression evaluator in .NET. NCalc can parse any expression and evaluate the result, including static or dynamic parameters and custom functions.

Table of Contents

• Operators: Available standard operators and structures.
• Values: Authorized values like types and functions.
• Functions: List of already implemented functions.
• Parameters: How to use parameters expressions.
• Handling Errors: How to handle errors.
• Case Sensitivity: Options in how to handle case sensitivity.
• Overflow Handling: How to handle overflow with binary arithmetic operations
• Async Support: How and when to use async.
• Caching: How caching works.
• Improve performance: How to use compilation of expressions to CLR lambdas.
• Dependency Injection: Bring expressions to the next level with dependency injection.
• Architecture: Check this article to learn how NCalc works.
• Benchmarks: Check some numbers about the speed of some NCalc components.

Functionalities

Simple Expressions

var expression = new Expression("2 + 3 * 5");
Debug.Assert(17 == expression.Evaluate());

.NET Data Types

Debug.Assert(123456 == new Expression("123456").Evaluate()); // integers
Debug.Assert(new DateTime(2001, 01, 01) == new Expression("#01/01/2001#").Evaluate()); // datetime
Debug.Assert(123.456 == new Expression("123.456").Evaluate()); // floating point numbers
Debug.Assert(true == new Expression("true").Evaluate()); // booleans
Debug.Assert("azerty" == new Expression("'azerty'").Evaluate()); // strings

Mathematical functional from System.Math**

Debug.Assert(0 == new Expression("Sin(0)").Evaluate());
Debug.Assert(2 == new Expression("Sqrt(4)").Evaluate());
Debug.Assert(0 == new Expression("Tan(0)").Evaluate());

Custom Functions

var expression = new Expression("SecretOperation(3, 6)");
expression.Functions["SecretOperation"] = (args) => {
    return (int)args[0].Evaluate() + (int)args[1].Evaluate();
};

Debug.Assert(9 == expression.Evaluate());

Unicode Characters

Debug.Assert("経済協力開発機構" == new Expression("'経済協力開発機構'").Evaluate());
Debug.Assert("Hello" == new Expression(@"'\u0048\u0065\u006C\u006C\u006F'").Evaluate());
Debug.Assert("だ" == new Expression(@"'\u3060'").Evaluate());
Debug.Assert("\u0100" == new Expression(@"'\u0100'").Evaluate());

Parameters - Static and Dynamic

var expression = new Expression("Round(Pow([Pi], 2) + Pow([Pi2], 2) + [X], 2)");

expression.Parameters["Pi2"] = new Expression("Pi * [Pi]");
expression.Parameters["X"] = 10;

expression.DynamicParameters["Pi"] = _ => {
    Console.WriteLine("I'm evaluating π!");
    return 3.14;
};

Debug.Assert(117.07 == expression.Evaluate());

Lambda Expressions

var expression = new Expression("1 + 2");
Func<int> function = expression.ToLambda<int>();
Debug.Assert(function()); //3