执行"cabal install hoogle"时出错

Question

当我跑步时cabal install hoogle,我得到以下内容:

setup: The program happy version >=1.17 is required but it could not be found
cabal: Error: some packages failed to install
haskell-src-exts-1.13.3 failed during the configure step the exeption is ExitFailure 1

$ghc -V
The Glorious Glasgow Haskell Compilation System, version 7.4.1

如何解决这样的问题？

Answer 1

而不是cabal install hoogle,运行cabal install alex happy && cabal install hoogle.

在hackage许多软件包需要alex和happy,因此它是后安装他们好主意cabal update.