评估数学EX pressions最佳和最短的路 [英] Best and shortest way to evaluate mathematical expressions

问题描述

有很多算法来评估EX pressions，例如：

There are many algorithms to evaluate expressions, for example:

1. 通过递归下降
2. 调度场算法
3. 逆波兰式

1. By Recursive Descent
2. Shunting-yard algorithm
3. Reverse Polish notation

有没有办法来评价使用C＃.NET的反射或其他现代.NET技术的所有数学EX pression？

Is there any way to evaluate any mathematical expression using C# .net reflection or other modern .net technology?

推荐答案

继托马斯的答案，它实际上可以访问（DE precated）的JScript库直接从C＃中，这意味着您可以使用JScript中的等效评估的功能。

Further to Thomas's answer, it's actually possible to access the (deprecated) JScript libraries directly from C#, which means you can use the equivalent of JScript's eval function.

using Microsoft.JScript;        // needs a reference to Microsoft.JScript.dll
using Microsoft.JScript.Vsa;    // needs a reference to Microsoft.Vsa.dll

// ...

string expr = "7 + (5 * 4)";
Console.WriteLine(JScriptEval(expr));    // displays 27

// ...

public static double JScriptEval(string expr)
{
    // error checking etc removed for brevity
    return double.Parse(Eval.JScriptEvaluate(expr, _engine).ToString());
}

private static readonly VsaEngine _engine = VsaEngine.CreateEngine();

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