1 files changed, 43 insertions, 13 deletions
diff --git a/src/CabalHelper/Compiletime/Types.hs b/src/CabalHelper/Compiletime/Types.hs
index 77c3255..10fe916 100644
--- a/src/CabalHelper/Compiletime/Types.hs
+++ b/src/CabalHelper/Compiletime/Types.hs
@@ -14,7 +14,8 @@
 -- You should have received a copy of the GNU General Public License
 -- along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-{-# LANGUAGE DeriveGeneric, DeriveDataTypeable, DefaultSignatures #-}
+{-# LANGUAGE DeriveGeneric, DeriveDataTypeable, DefaultSignatures,
+  KindSignatures, ImplicitParams, ConstraintKinds #-}
 
 {-|
 Module      : CabalHelper.Compiletime.Types
@@ -25,18 +26,47 @@ License     : GPL-3
 module CabalHelper.Compiletime.Types where
 
 import Data.Version
+import Data.Typeable
+import GHC.Generics
 
-data Options = Options {
-          oHelp          :: Bool
-        , oVerbose       :: Bool
-        , oGhcProgram    :: FilePath
-        , oGhcPkgProgram :: FilePath
-        , oCabalProgram  :: FilePath
-        , oCabalVersion  :: Maybe Version
-        , oCabalPkgDb    :: Maybe PackageDbDir
-}
+type Env = (?opts :: CompileOptions)
 
-newtype PackageDbDir = PackageDbDir { unPackageDbDir :: FilePath }
+-- | Paths or names of various programs we need.
+data Programs = Programs {
+      -- | The path to the @cabal@ program.
+      cabalProgram  :: FilePath,
+
+      -- | The path to the @ghc@ program.
+      ghcProgram    :: FilePath,
+
+      -- | The path to the @ghc-pkg@ program. If
+      -- not changed it will be derived from the path to 'ghcProgram'.
+      ghcPkgProgram :: FilePath
+    } deriving (Eq, Ord, Show, Read, Generic, Typeable)
+
+-- | Default all programs to their unqualified names, i.e. they will be searched
+-- for on @PATH@.
+defaultPrograms :: Programs
+defaultPrograms = Programs "cabal" "ghc" "ghc-pkg"
+
+data CompileOptions = CompileOptions
+    { oVerbose       :: Bool
+    , oCabalPkgDb    :: Maybe PackageDbDir
+    , oCabalVersion  :: Maybe Version
+    , oPrograms      :: Programs
+    }
 
-defaultOptions :: Options
-defaultOptions = Options False False "ghc" "ghc-pkg" "cabal" Nothing Nothing
+oCabalProgram :: Env => FilePath
+oCabalProgram = cabalProgram $ oPrograms ?opts
+
+oGhcProgram :: Env => FilePath
+oGhcProgram = ghcProgram $ oPrograms ?opts
+
+oGhcPkgProgram :: Env => FilePath
+oGhcPkgProgram = ghcPkgProgram $ oPrograms ?opts
+
+defaultCompileOptions :: CompileOptions
+defaultCompileOptions =
+    CompileOptions False Nothing Nothing defaultPrograms
+
+newtype PackageDbDir = PackageDbDir { unPackageDbDir :: FilePath }