A simple lib in C# for parsing and evaluating expressions. To get it install with nuget:
Install-Package Soukoku.ExpressionParser
This lib supports most common operators.
+addition-subtraction/negative*multiplication/division%modulus&bitwise and|bitwise or!logical negation&&logical and||logical or<less than<=less than or equals>greater than>=greater than or equals==equals!=not equals++preincrement--predecrement- basic functions (
pow,cos,sin,tan)
Create an instance of the Evaluator and call EvalueateInfix.
Expressions can contain simple math or functions.
The result can be retrieved with a ToString(). If an expression is not supported
you will get a NotSupportedException.
var context = new EvaluationContext();
var evaluator = new Evaluator(context);
var result = evaluator.Evaluate("33 + 55");
Console.WriteLine(result.ToString()); // should be "88"
result = evaluator.Evaluate("pow(2,8)");
Console.WriteLine(result.ToString()); // should be "256"The evaluator does its work in stages:
- Parse input string into tokens
- Arrange tokens into Reverse Polish notation
- Perform the evaluation
The logical operations will result in a number with 1 being true and 0 being false.
The lib only comes with some built-in functions. It's possible to add your own by registering a custom routine.
var context = new EvaluationContext();
// This custom function has no parameters and always returns 5.
// The return value of a function is an ExpressToken with string value.
var myFunc = new FunctionRoutine(0, (ctx, parameters) => new ExpressionToken("5"));
context.RegisterFunction("always5", myFunc);
var evaluator = new Evaluator(context);
var result = evaluator.Evaluate("10 + always5()");
Console.WriteLine(result.ToString()); // should be "15"Because the use of functions, floating-point numbers can only use period as the decimal separator (i.e. only "2.5" is supported, not "2,5").