From f1103f8f69939fd70e358ac06c022306b6678afd Mon Sep 17 00:00:00 2001
From: John MacFarlane <jgm@berkeley.edu>
Date: Sun, 5 Jul 2015 13:50:10 -0700
Subject: Make cabal require hsb2hs >= 0.3.1.

This is done by adding `hookedPrograms` in `Setup.hs`,
which allows us to include `hsb2hs` in Build-Tools in cabal.
---
 Setup.hs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

(limited to 'Setup.hs')

diff --git a/Setup.hs b/Setup.hs
index c28e45fdd..a328c75a7 100644
--- a/Setup.hs
+++ b/Setup.hs
@@ -23,18 +23,35 @@ import Distribution.PackageDescription (PackageDescription(..), FlagName(..))
 import System.Process ( rawSystem )
 import System.FilePath ( (</>) )
 import System.Directory ( findExecutable )
+import Distribution.Verbosity ( Verbosity )
 import Distribution.Simple.Utils (info, notice, installOrdinaryFiles)
 import Distribution.Simple.Setup
+import Distribution.Simple.Program (simpleProgram, Program(..))
 import Distribution.Simple.LocalBuildInfo
+import Data.Version
+import System.Process (readProcess)
+import Text.ParserCombinators.ReadP (readP_to_S, skipSpaces, eof)
 import Control.Monad (when)
 
 main :: IO ()
 main = defaultMainWithHooks $ simpleUserHooks {
       -- enable hsb2hs preprocessor for .hsb files
       hookedPreProcessors = [ppBlobSuffixHandler]
+    , hookedPrograms = [(simpleProgram "hsb2hs"){
+                           programFindVersion = findHsb2hsVersion }]
     , postCopy = installManPage
     }
 
+findHsb2hsVersion :: Verbosity -> FilePath -> IO (Maybe Version)
+findHsb2hsVersion verb fp = do
+  outp <- readProcess fp ["--version"] ""
+  case readP_to_S (do v <- parseVersion
+                      skipSpaces
+                      eof
+                      return v) outp of
+       ((v,""):_) -> return (Just v)
+       _          -> return Nothing
+
 ppBlobSuffixHandler :: PPSuffixHandler
 ppBlobSuffixHandler = ("hsb", \_ lbi ->
   PreProcessor {
-- 
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