You'll need to install ghc which comes up with Haskell platform in order to be able to compile jhc (John's Haskell Compiler). You should notice that jhc will only work under Linux or Mac.

你只需要安装 Haskell平台所带的 ghc来兼容 jhc（John的Haskell编译器），不过你必须注意的是，jhc只能运行在Linux或者Mac平台下。

youdao

Correspondents say the notice comes at a sensitive time in Pakistani politics, as Islamabad is under increasing US pressure to eliminate the Taliban and al-Qaeda along the Afghan border.

BBC: Explain emergency, Musharraf told