CODEWITHSUNDEEP
c#.net
Alex Kremer
Alex Kremer

Reputation: 128

Dynamic C# Formula Evaluation

Given a dynamic if statement in a String is there a method in .net to evaluate and return the correct result.

I.E.

    static void Main(string[] args)
    {
        String a = "if(\"Alex\" == \"Alex\"){return 1;}else{return 0;}";
        passThroughTest.Program.evalStatement(a);
    }
    public static void evalStatement(String statement)
    {

        //Evaluation of Statement

     }

This isn't perfect but in this case the end result would be a 1. This seems 'stupid' from this point of view, but its for a more complex engine which needs to draw on similar syntax to evaluate.

Am I at a point where I need to write a parser of some sort and evaluate the statements...?

Thanks for your help!

Upvotes: 1

Views: 3136

Answers (3)

AZ.
AZ.

Reputation: 7583

  • You can use javascript.net

    Sample code from their website:

    // Initialize a context
using (JavascriptContext context = new JavascriptContext()) {

    // Setting external parameters for the context
    context.SetParameter("console", new SystemConsole());
    context.SetParameter("message", "Hello World !");
    context.SetParameter("number", 1);

    // Script
    string script = @"
        var i;
        for (i = 0; i < 5; i++)
            console.Print(message + ' (' + i + ')');
        number += i;
    ";

    // Running the script
    context.Run(script);

    // Getting a parameter
    Console.WriteLine("number: " + context.GetParameter("number"));
}

  • Or use C# expression tree, see Building Expression Evaluator with Expression Trees

Upvotes: 3

Arash Aghlara
Arash Aghlara

Reputation: 350

You can also do something like this:

var expression="(\"Alex\" == \"Alex\") ? 1:0"; 
var res = FlexRule.DynamicEvaluation.ExpressionEval.Default.Compute(null, expression);

For more details information of expression please have a look at http://wiki.flexrule.com/index.php?title=Expression

Upvotes: 0

LightStriker
LightStriker

Reputation: 21024

What I think you are looking for is the CSharpCodeProvider : http://msdn.microsoft.com/en-us/library/microsoft.csharp.csharpcodeprovider.aspx

This allows you to compile or evaluate C# code from a source and run it. It might not be as easy as evaluating a single "if" case, as when you compile C#, you are expected to have the whole syntax coming with it.

Upvotes: 3

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