[Haskell-beginners] Problems installing TagSoup.Parsec

[Daniel Fischer]

Am Mittwoch 03 Februar 2010 01:19:49 schrieb Mark Wong-VanHaren:
> Hi, Daniel-
>
> Many thanks for your help.  Your instructions were very clear and
> worked perfectly.
>
> The only snag I encountered was a separate problem I had created for
> myself, which I'll mention here in case it may help someone else...
>
> I (thought I) wanted to uninstall TagSoup 0.8.  (I didn't really need
> to.)  Cabal doesn't provide an "uninstall" command, so I naively
> attempted to do it "manually" -- that is, to simply rm
> TagSoup-0.8-related files in my installation.
>
> This confused Cabal, which still "believed" (by virtue of config
> settings somewhere, presumably)

Cabal asks ghc-pkg what is installed, it doesn't keep a separate database.

> that TagSoup was still installed.  So
> cabal failed to find the actual files needed and complained.
>
> Rather than manually rm-ing things, the proper solution (I believe --
> at least it worked for me) was to use "ghc-pkg unregister tagsoup".

Right.

First unregister the packages.
Then you can delete the files if you want to.

>
> Anyway, thanks again for your help, Daniel.  Cheers,
> -Mark