[Haskell-cafe] "build depends:" in a .cabal file

Duncan Coutts duncan.coutts at worc.ox.ac.uk
Mon Aug 18 07:20:05 EDT 2008

On Mon, 2008-08-18 at 03:37 -0500, Galchin, Vasili wrote:
> Hello,
>      It seems to me that the "build depends" attribute/field is only
> informational, i.e. it doesn't cause "faulting in" dependencies if not
> present? If true, this seems to be a deficiency in cabal. ??

I'm not quite sure what you mean. They are certainly not just
informational. If you miss dependencies then the package will not

If by "faulting in" you mean downloading and installing missing
dependencies, then that's exactly what the cabal-install tool does.

As you mention in your other email, Cabal and cabal-install do indeed
access the db of installed packages and build a dependency graph.
cabal-install also uses a simple constraint solver to find a
satisfactory dep graph of installable packages.


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