Get Started

Installation

dotnet add package xFunc.Maths

Parse your first expression

var processor = new Processor();
var exp = processor.Parse("x ^ 2");

Note: You can use Parser instead of Processor.

The exp variable will contain the expression tree for x ^ 2 and will be equal to:

var exp = new Pow(
    Variable.X,
    new Number(2)
);

Evaluate it

Execute methods

Let's assume you have exp from the previous step. Now you can evaluate it but because the expression has the x variable you need to provide a value for it.

var parameters = new ExpressionParameters
{
    new Parameter("x", 10.0),
};
var result = exp.Execute(parameters);

The result will be equal to 100.0. All expressions have another overload of the Execute method, which doesn't accept any parameters, it is useful when your expression doesn't require any parameter, for example, 2 + 2. But be careful with this method because it could throw the NotSupportedException exception if the expression has any parameter or user-defined function.

Solve methods

If you don't need the expression tree at all, you can use Processor.Solve method. It will parse the string expression into the tree and immediately evaluate it for you:

var processor = new Processor();
var result = processor.Solve("10 ^ 2");

Analyze it

The xFunc library has the implementation of Visitor Pattern. It is called IAnalyzer<TResult>. You can implement your own analyzers but xFunc provides several built-in analyzers: Simplifier, Differentiator, TypeAnalyzer. I'm going to demonstrate analyzer based on Simplifier.

var simplifier = new Simplifier();
var exp = new Ln(new Variable("e")); // ln(e)
var result = exp.Analyze(simplifier);

The Simplifier allows you to simplify the expression, in the code shown above, the ln(e) expression will be simplified just to 1.

CLI Tool

xFunc has a CLI tool, to install it use the following command:

dotnet tool install -g xFunc.Cli

after that, you will be able to use the xfunc command in your terminal. It supports the following commands:

`xfunc parse`

This command parses the expression and outputs the string representation of it. Right now, its main purpose is testing (to check the expression was parsed correctly).

`xfunc solve`

This command evaluates the expression. For example:

xfunc solve "sin(90 'deg')"

`xfunc interactive`

This command launches the CLI tool in the interactive mode where you can enter each expression one by one, like:

> sin(90 'deg')
1
> cos(90 'deg')
0

To exit use Cmd+C or Cmd+D on Mac OS.

Also, you are able to save the current progress to a file (by using #save <path> command) and run it later with xfunc run.

`xfunc run`

Let's assume you saved your progress to the test.xf file with the following content:

sin(90 'deg')
cos(90 'deg')

So, you can execute it by:

xfunc run test.xf

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