从 C# 调用 F# 代码 [英] Call F# code from C#

问题描述

我正在玩 F# 和 C#，并想从 C# 调用 F# 代码.

I am playing around with F# and C#, and would like to call F# code from C#.

通过在同一个解决方案中有两个项目，并将 C# 代码的引用添加到 F# 项目，我设法让它在 Visual Studio 中以相反的方式工作.完成此操作后，我可以调用 C# 代码，甚至可以在调试时单步执行.

I managed to get it to work the other way around in Visual Studio by having two projects in the same solution, and adding a reference of the C# code to the F# project. After doing this, I could call C# code and even step through it while debugging.

我想要做的是来自 C# 的 F# 代码，而不是来自 F# 的 C# 代码.我向 C# 项目添加了对 F# 项目的引用，但它不像以前那样工作.我想知道这是否可以不手动完成.

What I am trying to do is F# code FROM C# instead of C# code from F#. I added a reference to the F# project to the C# project, but it isn't working the way it did before. I would like to know if this is possible without doing it manually.

推荐答案

以下是从 C# 调用 F# 的工作示例.

Below is a working example of calling F# from C#.

如您所见，我无法通过从添加引用...项目"选项卡中进行选择来添加引用.相反，我必须手动完成，方法是在添加引用...浏览"选项卡中浏览到 F# 程序集.

As you encountered, I was not able to add a reference by selecting from the "Add Reference ... Projects" tab. Instead I did have to do it manually, by browsing to the F# assembly in the "Add Reference ... Browse" tab.

------ F# 模块 -----

------ F# MODULE -----

// First implement a foldl function, with the signature (a->b->a) -> a -> [b] -> a
// Now use your foldl function to implement a map function, with the signature (a->b) -> [a] -> [b]
// Finally use your map function to convert an array of strings to upper case
//
// Test cases are in TestFoldMapUCase.cs
//
// Note: F# provides standard implementations of the fold and map operations, but the 
// exercise here is to build them up from primitive elements...

module FoldMapUCase.Zumbro
#light


let AlwaysTwo =
   2

let rec foldl fn seed vals = 
   match vals with
   | head :: tail -> foldl fn (fn seed head) tail
   | _ -> seed


let map fn vals =
   let gn lst x =
      fn( x ) :: lst
   List.rev (foldl gn [] vals)


let ucase vals =
   map String.uppercase vals

----- 模块的 C# 单元测试 -----

----- C# UNIT TESTS FOR THE MODULE -----

// Test cases for FoldMapUCase.fs
//
// For this example, I have written my NUnit test cases in C#.  This requires constructing some F#
// types in order to invoke the F# functions under test.


using System;
using Microsoft.FSharp.Core;
using Microsoft.FSharp.Collections;
using NUnit.Framework;

namespace FoldMapUCase
{
    [TestFixture]
    public class TestFoldMapUCase
    {
        public TestFoldMapUCase()
        {            
        }

        [Test]
        public void CheckAlwaysTwo()
        {
            // simple example to show how to access F# function from C#
            int n = Zumbro.AlwaysTwo;
            Assert.AreEqual(2, n);
        }

        class Helper<T>
        {
            public static List<T> mkList(params T[] ar)
            {
                List<T> foo = List<T>.Nil;
                for (int n = ar.Length - 1; n >= 0; n--)
                    foo = List<T>.Cons(ar[n], foo);
                return foo;
            }
        }


        [Test]
        public void foldl1()
        {
            int seed = 64;
            List<int> values = Helper<int>.mkList( 4, 2, 4 );
            FastFunc<int, FastFunc<int,int>> fn =
                FuncConvert.ToFastFunc( (Converter<int,int,int>) delegate( int a, int b ) { return a/b; } );

            int result = Zumbro.foldl<int, int>( fn, seed, values);
            Assert.AreEqual(2, result);
        }

        [Test]
        public void foldl0()
        {
            string seed = "hi mom";
            List<string> values = Helper<string>.mkList();
            FastFunc<string, FastFunc<string, string>> fn =
                FuncConvert.ToFastFunc((Converter<string, string, string>)delegate(string a, string b) { throw new Exception("should never be invoked"); });

            string result = Zumbro.foldl<string, string>(fn, seed, values);
            Assert.AreEqual(seed, result);
        }

        [Test]
        public void map()
        {
            FastFunc<int, int> fn =
                FuncConvert.ToFastFunc((Converter<int, int>)delegate(int a) { return a*a; });

            List<int> vals = Helper<int>.mkList(1, 2, 3);
            List<int> res = Zumbro.map<int, int>(fn, vals);

            Assert.AreEqual(res.Length, 3);
            Assert.AreEqual(1, res.Head);
            Assert.AreEqual(4, res.Tail.Head);
            Assert.AreEqual(9, res.Tail.Tail.Head);
        }

        [Test]
        public void ucase()
        {
            List<string> vals = Helper<string>.mkList("arnold", "BOB", "crAIg");
            List<string> exp = Helper<string>.mkList( "ARNOLD", "BOB", "CRAIG" );
            List<string> res = Zumbro.ucase(vals);
            Assert.AreEqual(exp.Length, res.Length);
            Assert.AreEqual(exp.Head, res.Head);
            Assert.AreEqual(exp.Tail.Head, res.Tail.Head);
            Assert.AreEqual(exp.Tail.Tail.Head, res.Tail.Tail.Head);
        }

    }
}

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