Tag: 函数组成

runST和函数组成

为什么这个types检查： runST $ return $ True 虽然以下不： runST . return $ True GHCI抱怨： Couldn't match expected type `forall s. ST s c0' with actual type `m0 a0' Expected type: a0 -> forall s. ST s c0 Actual type: a0 -> m0 a0 In the second argument of `(.)', namely `return' In the expression: runST . […]