giorgi/math-expression-evaluator

A C# library for parsing mathemitical expressions with support for parentheses and variables.

Hi there 👋 I'm Giorgi

I am a software developer with more than a decade of experience, working mainly with C#, ASP.NET Core, REST, GraphQL, MAUI, Xamarin, Entity Framework Core, AWS, Azure, and SQL Server. I have also worked with many other frameworks and systems such as ASP.NET MVC, ASP.NET Web API, WCF, Avalonia, WinForms, Oracle, and many more. Top 1% on Stack Overflow, member of Top 3% freelance software developers network and InfoQ Editor.

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math-expression-evaluator's Issues

[Feature Request] Make ExpressionEvaluator.Evaluate(expression, dictionary) public

It would be helpful for me, dynamically creating a list of variables, to simply pass a Dictionary

Unable to parse 5 * -3

Trying to parse this throws a StackEmptyException

Would love to see support for unary minus

Right now I hacked the code for simple cases by doing this

  private void EvaluateWhile(Func<bool> condition)
    {
        while (condition())
        {
            var right = expressionStack.Pop();
            var left = expressionStack.Count==0 ? Expression.Constant(0m) : expressionStack.Pop();

            expressionStack.Push(((Operation)operatorStack.Pop()).Apply(left, right));
        }
    }

I.e. when the left operand is missing make it 0.

Thank you

For making Advent of Code 2020 - Day 18 easy for me.
Great readable library where I could easily adjust the operator precedence.

Cannot add variables as named arguments

Consider the following code:

        var ev = new ExpressionEvaluator(CultureInfo.InvariantCulture);

        Decimal x = 0;
        Decimal.TryParse(mixedValue.ToString(CultureInfo.InvariantCulture), out x);

        ev.Evaluate(customFormula, x: x);

It fails, saying that there is no a parameter named x, so, how can I add explicitly named variables?

A little suggestion

Hi,

I am using this project for my work.
in short word, it is a great function !
However, I think it will be better if there are more operators like pow(^) absolute(||) etc...

Again, many thanks for this awesome project.

Regional setting

Hi, i have an issue with the regional setting of 2 pc running the same code, the issue is that one of them has configured regional setting as spanish with decimal sign as "." and the other is english with decimal sign as ",". If we use a decimal value on the format "1.002", for example, on the formula the spanish evaluate the formula ok and the english not. There is no way to set culture info to avoid this problem?
Otherwise we have to replace string before evaluate.

Latest nuget package

I had some trouble with the latest nuget package. It does not seem to contain the latest ExpressionEvaluator class. The fixes for Culture support are missing.