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) 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". Anyway, thanks again for your help, Daniel. Cheers, -Mark 2010/2/1 Daniel Fischer :

Am Montag 01 Februar 2010 21:21:12 schrieb Mark Wong-VanHaren:

...

Hi, folks-

I'm a Haskell newbie.  There's a very real chance my question has a simple answer.

Yes and no. The problem is that the build-depends field of tagsoup- parsec.cabal doesn't specify an upper bound on the version of tagsoup to use. Thus cabal tries to build it with the latest and greates tagsoup, 0.8. Neill Mitchell changed the tagsoup API, bad .cabal files break.

Fix: unpack tagsoup-parsec-0.0.6, open the .cabal file, change

Library   Build-Depends:  base<5, tagsoup, parsec<3

to

Library   Build-Depends:  base<5, tagsoup < 0.7, parsec<3

$ cd tagsoup-parsec-0.0.6 $ cabal install

email maintainer of tagsoup-parsec to fix it (adapt to new tagsoup API).

...

I wish to use the library Text.HTML.TagSoup.Parsec ( http://hackage.haskell.org/package/tagsoup-parsec), which looks very cool.

When I attempt to install it, I get this error:

# cabal install tagsoup-parsec Resolving dependencies... Configuring tagsoup-parsec-0.0.6... Preprocessing library tagsoup-parsec-0.0.6... Building tagsoup-parsec-0.0.6... [1 of 1] Compiling Text.HTML.TagSoup.Parsec ( Text/HTML/TagSoup/Parsec.hs, dist/build/Text/HTML/TagSoup/Parsec.o )

Text/HTML/TagSoup/Parsec.hs:37:5:    `Tag' is not applied to enough type arguments    Expected kind `*', but `Tag' has kind `* -> *'    In the type synonym declaration for `WholeTag' cabal: Error: some packages failed to install: tagsoup-parsec-0.0.6 failed during the building phase. The exception was: exit: ExitFailure 1

It would seem to be a type mismatch between TagSoup.Parsec and the base TagSoup (on which it depends).

Suspecting that the version-number dependency information might be incorrect, I tried uninstalling TagSoup and reinstalling an older version. This didn't help.

Can anyone steer me in the right direction?

Thanks! -Mark