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AntonovAnton / math.evaluation

This .NET library allows you to evaluate and compile any mathematical expression from a string dynamically at runtime. It supports a wide range of operations and allows for the use of custom variables, operators, and functions. The evaluator can be configured for different contexts, such as scientific, programming, boolean math expressions.
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Error of evaluating the expression. 'Infinity' is not recognizable. Invalid token at position 0 #47

Closed Bykiev closed 2 months ago

Bykiev commented 2 months ago

Describe the bug

Error of evaluating the expression. 'Infinity' is not recognizable. Invalid token at position 0

To Reproduce

Steps to reproduce the issue:

string expr = (double.MaxValue + 2e+300).ToString(CultureInfo.InvariantCulture);
Console.WriteLine(expr.Evaluate(CultureInfo.InvariantCulture));

Expected behavior

The result of expression evaluation should be Double.PositiveInfinity

Actual Behavior

Exception is thrown

AntonovAnton commented 2 months ago

It will work if you are evaluating C# math expression as a string: Console.WriteLine("double.MaxValue + 2e+300".Evaluate(new DotNetStandartMathContext()));

AntonovAnton commented 2 months ago

If you want the evaluator understands "Invinity" string as a PositiveInfinity you can specify context:

            var context = new MathContext();
            context.BindVariable(double.PositiveInfinity, "Infinity");
            string expr = (double.MaxValue + 2e+300).ToString(CultureInfo.InvariantCulture);
            Console.WriteLine(expr.Evaluate(context));
AntonovAnton commented 2 months ago

Describe the bug

Error of evaluating the expression. 'Infinity' is not recognizable. Invalid token at position 0

To Reproduce

Steps to reproduce the issue:

string expr = (double.MaxValue + 2e+300).ToString(CultureInfo.InvariantCulture);
Console.WriteLine(expr.Evaluate(CultureInfo.InvariantCulture));

Expected behavior

The result of expression evaluation should be Double.PositiveInfinity

Actual Behavior

Exception is thrown

Hi! The evaluator returns double not a string, ToString() of the double type represents double.PositiveInfinity as "Infinity" or "∞" so I can add support of these notations to the DotNetStandartMathContext if you use this context the expression will evaluate "Infinity" or "∞" as double.PositiveInfinity. Do you agree to use the DotNetStandartMathContext? Without specified math context the evaluator supports only +-*/(). Also ScientificMathContext supports "∞" notation at the moment.