[Haskell-cafe] Error in Installing Data.deriveTH
daniel.is.fischer at googlemail.com
Sat Sep 17 13:38:32 CEST 2011
On Saturday 17 September 2011, 12:41:17, mukesh tiwari wrote:
> > Does there exist an unversioned ghc? What does
> > $ which ghc
> > print?
> It prints nothing .
Okay, since cabal defaults to looking for plain "ghc" when no compiler is
explicitly passed, that explains why it didn't work without --with-compiler
Normally, when ghc is installed, it creates versionless symlinks to the
actual scripts/binaries, so there should be symbolic links
ghc, ghci, ghc-pkg
to the versioned things (and haddock->haddock-ghc-7.2.1,
runhaskell->runghc), many programmes expect unversioned tools by default.
It might be that your install is broken, but probably creating the symlinks
yourself (read the ln man-page and be careful when you create them) will be
> ntro at ntro-HP-dx2480-MT-NA121PA:/usr/local/bin$ ls ghc*
> ghc-7.2.1 ghci-7.2.1 ghc-pkg-7.2.1
Those should be linked to.
> ntro at ntro-HP-dx2480-MT-NA121PA:/usr/local/bin$ ls
> django-admin.py eggy eric4-compare eric4-doc
> eric4-pluginrepository eric4-re eric4-trpreviewer
> eric4-webbrowser ghc-pkg-7.2.1 hp2ps runghc spyder
> Editra eric4 eric4-configure eric4-editor
> eric4-pluginuninstall eric4-sqlbrowser eric4-uipreviewer
> ghc-7.2.1 haddock hpc runhaskell UTscapy
> Editra.pyw eric4-api eric4-diff eric4-plugininstall
> eric4-qregexp eric4-tray eric4-unittest
> ghci-7.2.1 haddock-ghc-7.2.1 hsc2hs scapy
> So should i delete ghc-6.12.1 from /var/lib
Optional. It shouldn't cause any problems (unless you need the space).
> and move the ghc-7.2.1 from
> /usr/local/lib to /var/lib to execute cabal install <pkg-name> -v
> --dry-run ?
No, leave /usr/local/lib where it is, moving it would cause massive
breakage. For example, /usr/bin/ghc-7.2.1 expects the libraries and
The only problem was that cabal looked for "ghc" which no longer exists on
your path. That fact is somewhat dubious, as normally installing ghc
creates the symlinks, but creating them is probably all that's needed if
invoking ghc-7.2.1 works.
> As /usr/local/bin is already in the path i don't need to
> move any files from here. Am i correct ?
Don't move anything. If your ghc-7.2.1 is broken, you will need to
reinstall (that or another version), otherwise you can work with always
using (and passing) the explicit version or, more conveniently, create the
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