[Haskell-cafe] Re: ANN: Takusen 0.8

Alistair Bayley alistair at abayley.org
Wed Mar 5 17:45:57 EST 2008

> ross:
> > If you want to use your own Setup.hs, you need to specify a Build-Type of
>  > Custom, not Simple.  Some tools will ignore your Setup.hs if you specify
>  > Simple.  I guess the message "If possible use 'build-type: Simple'" is
>  > a bit confusing.
> Yes, cabal-setup found this confusing.
>  I wonder if its possible to just use flags for building the different
>  takusen backends, rather than this automagic uber-discovery?

Mebbe... are you suggesting command-line flags, or cabal flags? I'm
certainly open to suggestions for improving the install.

Part of the motivation for discovery is that for PostgreSQL, you need
to run a program (with various flags) which spits out the locations
for include files, libs, etc (presumably because they can vary on
different platforms? I'm not really sure why, being a Windows chimp
myself). Once you do this, it's not much more effort to extend it to
detect other DBMS installations, assuming they have standard layouts
(Oracle certainly does).

The alternative approach is what HSQL did (and I think HDBC, too),
which is to have a base package, and then a separate package for each
back-end. I considered this, but I much prefer to have the library
available as a single download-build-install process. This makes for a
nicer user experience (at the expense of more work for the package

Isn't this partly the point of cabal's Setup.hs i.e. to accommodate
more complex build processes than cabal provides out-of-the-box?
Obviously there's some pain, because the cabal API is not stable, but
c'est la vie...


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