SetupHsenv.hs

import Data.Conduit.Shell
import qualified Data.Conduit.Shell.Segments as SH

main =
  run (do hsenv
          cur:_ <- SH.strings latestStackage
          sed ("s/remote-repo:.*/remote-repo: stackage:http:\\/\\/www.stackage.org\\/stackage\\/" ++
               cur ++ "/")
              ".hsenv/cabal/config"
              "-i"
          bash "-c"
               "source .hsenv/bin/activate; exec cabal update"
          bash "-c"
               "source .hsenv/bin/activate; exec cabal install --dry-run")

latestStackage =
  curl "-s" "http://www.stackage.org/alias/fpcomplete/unstable-ghc78-inclusive" "-D/dev/stdout" $|
  egrep "-o" "stackage\\.org/stackage/[a-z0-9]+" $|
  egrep "-o" "[a-z0-9]+$"