pkgs/development/haskell-modules/patches/ghc-paths-nix.patch

   1 diff -Naur ghc-paths-0.1.0.9/GHC/Paths.hs ghc-paths-0.1.0.9-new/GHC/Paths.hs
   2 --- ghc-paths-0.1.0.9/GHC/Paths.hs      2012-12-16 13:53:45.720148396 +0100
   3 +++ ghc-paths-0.1.0.9-new/GHC/Paths.hs  2012-12-16 17:22:12.765576568 +0100
   4 @@ -1,13 +1,35 @@
   5  {-# LANGUAGE CPP #-}
   6 +{-# LANGUAGE ScopedTypeVariables #-}
   7
   8  module GHC.Paths (
   9          ghc, ghc_pkg, libdir, docdir
  10    ) where
  11
  12 +import Control.Exception as E
  13 +import Data.Maybe
  14 +import System.Environment
  15 +import System.IO.Unsafe
  16 +
  17 +-- Yes, there's lookupEnv now, but we want to be compatible
  18 +-- with older GHCs.
  19 +checkEnv :: String -> IO (Maybe String)
  20 +checkEnv var = E.catch (fmap Just (getEnv var))
  21 +                       (\ (e :: IOException) -> return Nothing)
  22 +
  23 +nixLibdir, nixDocdir, nixGhc, nixGhcPkg :: Maybe FilePath
  24 +nixLibdir = unsafePerformIO (checkEnv "NIX_GHC_LIBDIR")
  25 +nixDocdir = unsafePerformIO (checkEnv "NIX_GHC_DOCDIR")
  26 +nixGhc    = unsafePerformIO (checkEnv "NIX_GHC")
  27 +nixGhcPkg = unsafePerformIO (checkEnv "NIX_GHCPKG")
  28 +{-# NOINLINE nixLibdir #-}
  29 +{-# NOINLINE nixDocdir #-}
  30 +{-# NOINLINE nixGhc    #-}
  31 +{-# NOINLINE nixGhcPkg #-}
  32 +
  33  libdir, docdir, ghc, ghc_pkg :: FilePath
  34
  35 -libdir  = GHC_PATHS_LIBDIR
  36 -docdir  = GHC_PATHS_DOCDIR
  37 +libdir  = fromMaybe GHC_PATHS_LIBDIR  nixLibdir
  38 +docdir  = fromMaybe GHC_PATHS_DOCDIR  nixDocdir
  39
  40 -ghc     = GHC_PATHS_GHC
  41 -ghc_pkg = GHC_PATHS_GHC_PKG
  42 +ghc     = fromMaybe GHC_PATHS_GHC     nixGhc
  43 +ghc_pkg = fromMaybe GHC_PATHS_GHC_PKG nixGhcPkg