cabal-install不保留版本为happy

Question

I've trying to do cabal install hoogle but there is a hickup with the haskell-src-exts-1.13.5 dependency:

Configuring haskell-src-exts-1.13.5...
setup: The program happy version >=1.17 is required but it could not be found.

When I try to do cabal install happy it seems to finish successfully, but cabal-install does not retain the version:

>$ cabal list happy
* happy
    Synopsis: Happy is a parser generator for Haskell
    Default available version: 1.18.10
    Installed versions: [ Unknown ]
    Homepage: http://www.haskell.org/happy/
    License:  BSD3

As you can see the version is [ Unknown ] . It stays unknown, and cabal-install remains oblivious if I try to run cabal install happy again.

What gives?

Thanks in advance!

Answer 1

Looks like cabal does not show Installed versions for executables, but for libraries only.

Maybe cabal install happy somewhere to your home directory, for example in $HOME/.cabal/bin , and it's not in your PATH . cabal install happy show this path in some last lines. So you can add this path to your PATH and try to install haskell-src-exts again.