通过Cabal安装软件包时出错 - 种类不匹配

时间:2015-12-16 05:24:00

标签: haskell cabal-install arrows

我试图从这个git仓库安装软件包:https://github.com/dwincort/SettableArrow

我在我的目录中输入:

cabal install SettableArrow.cabal

在第187行收到此错误:

Kind mis-match
The first argument of `ArrowSwitch' should have kind `* -> * -> *',
but `a' has kind `*'
In the instance declaration for `ArrowSwitch (SA a)'

定义实例的行:

class Arrow a => ArrowSwitch a where
switch :: (Typeable b, Typeable c) => a b c -> a (b, Maybe (a b c)) c

187:

instance (Typeable a, ArrowSwitch a, ArrowLoop a , ArrowDelay a) => ArrowSwitch (SA a) where
   switch (SA def) = SA $ loop $ 
     second (delay def) >>> arr (\(((b,msf),et),prevSF) -> 
           ...

我的方面是错误还是代码有问题? 如果有人有兴趣,可以写一篇论文:

  

http://haskell.cs.yale.edu/wp-content/uploads/2015/10/dwc-yale-formatted-dissertation.pdf

0 个答案:

没有答案