小编Tom*_*akl的帖子

我正在尝试在Haskell中编写一个安全的超时评估函数.代码如下

import System.Timeout

compute, compute' :: Int -> Int
compute  i = sum [1..300000 + i]
compute' i = last $ repeat i

timedComp :: Int -> a -> IO (Maybe a)
timedComp timeLeft toCompute =
        timeout timeLeft go
    where
        go = toCompute `seq` return toCompute

main = do
    res <- timedComp 10000 (compute 0)
    print res

    res' <- timedComp 10000 (compute' 0)
    print res'

(我知道我只评价WHNF.)

当我运行main时,我只输出一个Nothing,然后程序挂起.我试图编译并运行程序多线程,但它没有帮助.试用GHC 7.6.3和7.8.3.有什么建议？