Re: [Haskelldb-users] unable to build

[<bri...@cs...>]

Ian Zimmerman wrote:
> itz@unicorn:~/src/haskelldb$ runghc Setup.hs configure --ghc
> *** Exception: Line 8: Parse of field 'extensions' failed
> itz@unicorn:~/src/haskelldb$ dpkg --list ghc6
> Desired=3DUnknown/Install/Remove/Purge/Hold
> | Status=3DNot/Installed/Config-files/Unpacked/Failed-config/Half-insta=
lled
> |/ Err?=3D(none)/Hold/Reinst-required/X=3Dboth-problems (Status,Err: up=
percase=3Dbad)
> ||/ Name                    Version                 Description
> +++-=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
-=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D-=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> ii  ghc6                    6.4-4.1                 GHC - the Glasgow H=
askell Compilation system
>=20
>=20

Short version: upgrade Cabal.

Longer version:

HSQL 1.7 requires a newer Cabal version that that included with GHC 6.4.=20
  I wanted HaskellDB to build with the same version of Cabal as HSQL=20
needs. Unfortunately the AllowUndecidableInstances extension is called=20
UndecidableInstances in recent Cabal versions. Thus I had to change=20
"AllowUndecidableInstances" to "UndecidableInstances" in the extensions=20
field.

So, either you can upgrade Cabal, which you need to do for HSQL anyway,=20
our you  can change the extensions fields in the Cabal files to work=20
with older Cabal versions:

$ perl -pi -e 's/UndecidableInstances/AllowUndecidableInstances/' \
    *.cabal driver-*/*.cabal


I wish Cabal files would be more compatible between versions, but I=20
guess that's difficult while we are still in the beginning of Cabal=20
development.

I've now added a note to the INSTALL file about the Cabal version=20
requirement.

/Bj=F6rn