design question

Ross Paterson ross at
Wed Jul 18 07:47:54 EDT 2007

On Wed, Jul 18, 2007 at 08:43:53AM +0200, Sascha Böhme wrote:
> in Distribution.PackageDescription, one library may be given, but in
> Distribution.InstalledPackageInfo, several libraryDirs, importDirs,
> includeDirs, haddockInterfaces, haddockHTMLs may exist. Why is this? How
> could there be more than one of these paths if there is just one
> library? I'm sure I miss some critical design decision.

The Library type includes a BuildInfo, which contains several fields
which are often similar to those in InstalledPackageInfo.  They're
not the same though, because BuildInfo contains information needed
to build the package, while InstalledPackageInfo contains information
needed to build other programs and packages that use this package.

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