X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=GHC%2FPtr.lhs;h=8087c77ff3054918fbafa12bfc9f1acb2bc82af9;hb=e3e2159dbf55edd3124d66533ff2c598f53aa811;hp=222524c5c6339409bd4be124ac67f6b3eb6e7333;hpb=d9a0d6f44a930da4ae49678908e37793d693467c;p=ghc-base.git

diff --git a/GHC/Ptr.lhs b/GHC/Ptr.lhs
index 222524c..8087c77 100644
--- a/GHC/Ptr.lhs
+++ b/GHC/Ptr.lhs
@@ -1,5 +1,6 @@
 \begin{code}
-{-# OPTIONS_GHC -fno-implicit-prelude #-}
+{-# OPTIONS_GHC -XNoImplicitPrelude #-}
+{-# OPTIONS_HADDOCK hide #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  GHC.Ptr
@@ -18,6 +19,12 @@
 module GHC.Ptr where
 
 import GHC.Base
+import GHC.Show
+import GHC.Num
+import GHC.List ( length, replicate )
+import Numeric          ( showHex )
+
+#include "MachDeps.h"
 
 ------------------------------------------------------------------------
 -- Data pointers.
@@ -56,7 +63,7 @@ alignPtr addr@(Ptr a) (I# i)
       0# -> addr;
       n -> Ptr (plusAddr# a (i -# n)) }
 
--- |Computes the offset required to get from the first to the second
+-- |Computes the offset required to get from the second to the first
 -- argument.  We have 
 --
 -- > p2 == p1 `plusPtr` (p2 `minusPtr` p1)
@@ -134,5 +141,19 @@ castFunPtrToPtr (FunPtr addr) = Ptr addr
 -- this assumption.
 castPtrToFunPtr :: Ptr a -> FunPtr b
 castPtrToFunPtr (Ptr addr) = FunPtr addr
+
+
+------------------------------------------------------------------------
+-- Show instances for Ptr and FunPtr
+
+instance Show (Ptr a) where
+   showsPrec _ (Ptr a) rs = pad_out (showHex (wordToInteger(int2Word#(addr2Int# a))) "")
+     where
+        -- want 0s prefixed to pad it out to a fixed length.
+       pad_out ls = 
+          '0':'x':(replicate (2*SIZEOF_HSPTR - length ls) '0') ++ ls ++ rs
+
+instance Show (FunPtr a) where
+   showsPrec p = showsPrec p . castFunPtrToPtr
 \end{code}