C#からHaskellの関数を呼ぶ

Haskell C#

stackoverflowのリンク先そのまんまなんだけどひとつ詰まったのでメモ
http://stackoverflow.com/questions/16615641/calling-haskell-from-c-sharp

動作確認環境

Windows 7 64 bit
GHC 7.8.3
Visual Studio Express 2013 for Windows Desktop

Haskellコード

Fibonacci.hs

{-# LANGUAGE ForeignFunctionInterface #-}

-- http://stackoverflow.com/questions/16615641/calling-haskell-from-c-sharp

module Fibonacci () where

import Data.Word
import Foreign.C.Types

fibs :: [Word32]
fibs = 1 : 1 : zipWith (+) fibs (tail fibs)

fibonacci :: Word8 -> Word32
fibonacci n =
  if n > 47
    then 0
    else fibs !! (fromIntegral n)

c_fibonacci :: CUChar -> CUInt
c_fibonacci (CUChar n) = CUInt (fibonacci n)

foreign export ccall c_fibonacci :: CUChar -> CUInt

Haskellコードのビルド

ghc --make -shared Fibonacci.hs
HSdll.dllができる

C#コード

VisualStudioのコンソールアプリケーションプロジェクト

Program.cs

using System;
using System.Runtime.InteropServices;

namespace ConsoleApplication1
{
    // http://stackoverflow.com/questions/16615641/calling-haskell-from-c-sharp
    public sealed class Fibonacci : IDisposable
    {
        [DllImport("HSdll.dll", CallingConvention = CallingConvention.Cdecl)]
        private static extern void hs_init(IntPtr argc, IntPtr argv);

        [DllImport("HSdll.dll", CallingConvention = CallingConvention.Cdecl)]
        private static extern void hs_exit();

        [DllImport("HSdll.dll", CallingConvention = CallingConvention.Cdecl)]
        private static extern UInt32 c_fibonacci(byte i);

        public Fibonacci()
        {
            Console.WriteLine("Initialising DLL...");
            hs_init(IntPtr.Zero, IntPtr.Zero);
        }

        public void Dispose()
        {
            Console.WriteLine("Shutting down DLL...");
            hs_exit();
        }

        public UInt32 fibonacci(byte i)
        {
            Console.WriteLine(string.Format("Calling c_fibonacci({0})...", i));
            var result = c_fibonacci(i);
            Console.WriteLine(string.Format("Result = {0}", result));
            return result;
        }
    }

    class MainClass
    {
        public static void Main(string[] args)
        {
            using(var fib = new Fibonacci())
            {
                fib.fibonacci(10);
            }

            Console.ReadLine();
        }
    }
}