On 18 jul 2007, at 08.43, Sascha Böhme wrote:
Hello,
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.
(Just a guess.) InstalledPackageDescription is different in that its format is not controlled by Cabal, but rather by the particular compiler. It happens to be the case, that the formats are very similar, but there are some differences among Hugs, nhc, GHC, etc.. This data structure just captures these. PackageDescription, OTOH, reflects Cabal's current capabilities. HTH, / Thomas