C#中的表达式树

Question

How can I convert this into expression tree or using linq so I can write function base on these expression hierarchy?.

I have seen this library but I am not sure I am on right path to https://csharpeval.codeplex.com/wikipage?title=Usage&referringTitle=Documentation

 max(avg(high1:3),avg(low1:3)) - min(avg(high1:3),avg(low1:3))

Answer 1

Compiling and executing codes at run time is always a bit challenging. The library that you mentioned is just a way.

You can use Roslyn which comes with C# 6.0 and Visual Studio 2015 by Microsoft and the C# team. You can't imagine how powerful is it. Here are some samples and walkthroughs:

https://github.com/dotnet/roslyn/wiki/Samples-and-Walkthroughs

And some other introductions:

https://en.wikipedia.org/wiki/.NET_Compiler_Platform

And here is some sample to create a REPL (something like what you want):

http://www.jayway.com/2015/05/09/using-roslyn-to-build-a-simple-c-interactive-script-engine/

Using Roslyn can simple have something like this:

var csScript =
    string.Format(@"
        var x = Math.Max(Math.Avg({0},3),Math.Avg(low1:3));
        x;
    ", high1, low1);
    //And this from the REPL
    Console.WriteLine(CSharpScriptEngine.Execute(csScript));