1 files changed, 70 insertions, 0 deletions
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
index 0000000..05a0ae1
--- /dev/null
+++ b/Setup.hs
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+#!/usr/bin/env runhaskell
+{-# LANGUAGE RecordWildCards #-}
+import Distribution.Simple
+import Distribution.Simple.Setup
+import Distribution.Simple.Install
+import Distribution.Simple.InstallDirs as ID
+import Distribution.Simple.LocalBuildInfo
+import Distribution.PackageDescription
+
+import Control.Applicative
+import Data.List
+import Data.Maybe
+import System.FilePath
+
+main :: IO ()
+main = defaultMainWithHooks $ simpleUserHooks { copyHook = xInstallTargetHook }
+
+xInstallTargetHook ::
+    PackageDescription -> LocalBuildInfo -> UserHooks -> CopyFlags -> IO ()
+xInstallTargetHook pd lbi _uh cf = do
+  let (extended, regular) = partition (isJust . installTarget) (executables pd)
+
+  let pd_regular = pd { executables = regular }
+
+  _ <- flip mapM extended $ \exe -> do
+    putStrLn $ "extended "  ++ show (exeName exe)
+
+    let
+        idirtpl          = installDirTemplates lbi
+        env              = installDirsTemplateEnv idirtpl
+        libexecdir'      = fromPathTemplate (libexecdir idirtpl)
+
+        pd_extended      = onlyExePackageDesc [exe] pd
+        install_target   = fromJust $ installTarget exe
+        install_target'  = ID.substPathTemplate env install_target
+        -- $libexec isn't a real thing :/ so we have to simulate it
+        install_target'' = substLibExec' libexecdir' install_target'
+
+    let lbi' = lbi {
+                 installDirTemplates =
+                     (installDirTemplates lbi) {
+                   bindir = install_target''
+                 }
+               }
+
+    install pd_extended lbi' cf
+
+  install pd_regular lbi cf
+
+ where
+   installTarget :: Executable -> Maybe PathTemplate
+   installTarget exe =
+    toPathTemplate <$> lookup "x-install-target" (customFieldsBI $ buildInfo exe)
+
+   substLibExec libexecdir "$libexecdir" = libexecdir
+   substLibExec _ comp = comp
+
+   substLibExec' dir =
+       withPT $
+           withSP $ map (substLibExec dir . dropTrailingPathSeparator)
+
+
+   withPT f pt = toPathTemplate $ f (fromPathTemplate pt)
+   withSP f p  = joinPath $ f (splitPath p)
+
+onlyExePackageDesc :: [Executable] -> PackageDescription -> PackageDescription
+onlyExePackageDesc exes pd = emptyPackageDescription {
+                     package = package pd
+                   , executables = exes
+                   }