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

[Duncan Coutts]

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
compile.

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.

Duncan