haskell - What's the type of LazyIO.readFile?

Question

I am trying to find the type of privacyContents in

privacyContents <- LazyIO.readFile $ markdownPath ++ "PRIVACY.md"

Is the type of this variable defined by the return type of LazyIO.readFile? And if the answer is yes, what is the return type of LazyIO.readFile?

Answer 1

您可以让 GHC 使用类型孔告诉您类型是什么。

只需在赋值后添加一个 let 语句：

...
privacyContents <- LazyIO.readFile $ markdownPath ++ "PRIVACY.md"
let _ = privacyContents :: _
...

当您编译程序或将其加载到 ghci 中时，您将被告知类型privacyContents是什么。

我的猜测是 LazyIO 对应于Data.Text.IO.Lazy它会产生privacyContents一个惰性文本值（即类型 Data.Text.Lazy.Text）。