ExpressiveParser Variables

The ExpressiveParser library provides the following standard constants, which you can use directly in the expressions or script.

You can also define your custom variables in a dictionary object and pass them to the Evaluate method as a parameter. To use your custom variables in an expression, specify the variable inside square brackets ([]) as shown below.

public static void Example1()
{
    var varibles = new Dictionary<string, object>()
    {
        { "myInt", 6 },
        { "myDouble", -3.6 },
        { "myStr", "Hello World" },
    };

    List<string> expressions = new List<string>()
    {
        "[myInt]",
        "[myDouble] + 3.0",
        "[myInt] + [myDouble]",
        "[myStr]",
        "[myStr] + \", you are learning Expression Evaluator\"",
    };

    foreach (var expression in expressions)
    {
        var exprObj = new Expression(expression);
        var result = exprObj.Evaluate(varibles);
        Console.WriteLine("{0} = {1}", expression, result);
    }
}

Let's execute the above code, and you will see the following output.

[myInt] = 6
[myDouble] + 3.0 = -0.6000000000000001
[myInt] + [myDouble] = 2.4
[myStr] = Hello World
[myStr] + ", you are learning Expression Evaluator" = Hello World, you are learning Expression Evaluator