如何在 WinGHCi 中运行这个 haskell 程序？

Question

以此为例： http://www.haskell.org/haskellwiki/99_questions/Solutions/32

(**) Determine the greatest common divisor of two positive integer numbers. Use Euclid's algorithm.

gcd' 0 y = y
gcd' x y = gcd' (y `mod` x) x
myGCD x y | x < 0     = myGCD (-x) y
          | y < 0     = myGCD x (-y)
          | y < x     = gcd' y x
          | otherwise = gcd' x y
The Prelude includes a gcd function, so we have to choose another name for ours. The function gcd' is a straightforward implementation of Euler's algorithm, and myGCD is just a wrapper that makes sure the arguments are positive and in increasing order.

A more concise implementation is:

myGCD :: Integer -> Integer -> Integer
myGCD a b
      | b == 0     = abs a
      | otherwise  = myGCD b (a `mod` b)

如何在 WinGHCi 中进行测试？运行 haskell 程序的步骤/工作流程是什么？

谢谢！

Answer 1

1. 将代码保存在.hs 文件中的某个位置，例如C:\Haskell\MyGCD.hs。

2. 启动 WinGHCi 并使用:cd 转到您保存它的目录，然后使用:load 加载它：

   Prelude> :cd C:\Haskell
   Prelude> :load MyGCD.hs
   [1 of 1] Compiling Main             ( MyGCD.hs, interpreted )
   Ok, modules loaded: Main.
   

3. 现在你可以玩这个函数了：

   *Main> myGCD 12 10
   2
   

输入:help了解更多信息，或查看Chapter 2: Using GHCi of the GHC User's Guide。