Add Data and Typeable instances to HsSyn

[ghc-hetmet.git] / compiler / utils / Util.lhs

diff --git a/compiler/utils/Util.lhs b/compiler/utils/Util.lhs
index 16a1628..fbbe767 100644 (file)
--- a/compiler/utils/Util.lhs
+++ b/compiler/utils/Util.lhs
@@ -7,7 +7,7 @@
 -- | Highly random utility functions
 module Util (
         -- * Flags dependent on the compiler build
-        ghciSupported, debugIsOn, ghciTablesNextToCode, picIsOn,
+        ghciSupported, debugIsOn, ghciTablesNextToCode, isDynamicGhcLib,
         isWindowsHost, isWindowsTarget, isDarwinTarget,
 
         -- * General list processing
@@ -30,6 +30,9 @@ module Util (
 
         isIn, isn'tIn,
 
+        -- * Tuples
+        fstOf3, sndOf3, thirdOf3,
+
         -- * List operations controlled by another list
         takeList, dropList, splitAtList, split,
         dropTail,
@@ -73,19 +76,22 @@ module Util (
         escapeSpaces,
         parseSearchPath,
         Direction(..), reslash,
+
+        -- * Utils for defining Data instances
+        abstractConstr, abstractDataType, mkNoRepType
     ) where
 
 #include "HsVersions.h"
 
 import Panic
 
+import Data.Data
 import Data.IORef       ( IORef, newIORef, atomicModifyIORef )
 import System.IO.Unsafe ( unsafePerformIO )
 import Data.List        hiding (group)
 import Control.Concurrent.MVar ( MVar, newMVar, newEmptyMVar )
 
 #ifdef DEBUG
-import qualified Data.List as List ( elem, notElem )
 import FastTypes
 #endif
 
@@ -138,11 +144,11 @@ ghciTablesNextToCode = True
 ghciTablesNextToCode = False
 #endif
 
-picIsOn :: Bool
-#ifdef __PIC__
-picIsOn = True
+isDynamicGhcLib :: Bool
+#ifdef DYNAMIC
+isDynamicGhcLib = True
 #else
-picIsOn = False
+isDynamicGhcLib = False
 #endif
 
 isWindowsHost :: Bool
@@ -181,6 +187,15 @@ nTimes 1 f = f
 nTimes n f = f . nTimes (n-1) f
 \end{code}
 
+\begin{code}
+fstOf3   :: (a,b,c) -> a    
+sndOf3   :: (a,b,c) -> b    
+thirdOf3 :: (a,b,c) -> c    
+fstOf3      (a,_,_) =  a
+sndOf3      (_,b,_) =  b
+thirdOf3    (_,_,c) =  c
+\end{code}
+
 %************************************************************************
 %*                                                                      *
 \subsection[Utils-lists]{General list processing}
@@ -891,3 +906,29 @@ reslash d = f
                   Backwards -> '\\'
 \end{code}
 
+%************************************************************************
+%*                                                                      *
+\subsection[Utils-Data]{Utils for defining Data instances}
+%*                                                                      *
+%************************************************************************
+
+These functions helps us to define Data instances for abstract types.
+
+\begin{code}
+abstractConstr :: String -> Constr
+abstractConstr n = mkConstr (abstractDataType n) ("{abstract:"++n++"}") [] Prefix
+\end{code}
+
+\begin{code}
+abstractDataType :: String -> DataType
+abstractDataType n = mkDataType n [abstractConstr n]
+\end{code}
+
+\begin{code}
+-- Old GHC versions come with a base library with this function misspelled.
+#if __GLASGOW_HASKELL__ < 612
+mkNoRepType :: String -> DataType
+mkNoRepType = mkNorepType
+#endif
+\end{code}
+