topologicalOrder :: GenericInstallPlan ipkg srcpkg iresult ifailure
                 -> [GenericPlanPackage ipkg srcpkg iresult ifailure]
topologicalOrder plan =
    map (planPkgOf plan)
  . Graph.topSort
  $ planGraph plan
topologicalOrder :: GenericInstallPlan ipkg srcpkg iresult ifailure
                 -> [GenericPlanPackage ipkg srcpkg iresult ifailure]
topologicalOrder plan =
    map (planPkgOf plan)
  . Graph.topSort
  $ planGraph plan
topologicalOrder plan =
    map (planPkgOf plan)
  . Graph.topSort
  $ planGraph plan