X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Futils%2FFastString.lhs;h=661b89eaf9b35ac459171f692fdc0b3850a95896;hb=22cf766063c99241e5f5fc2175a60fc63f7a36f3;hp=61750aabdb5ed065f37932030804596be4ff2ffc;hpb=affe92132329afa642bc83d74d5b07d14187e968;p=ghc-hetmet.git

diff --git a/ghc/compiler/utils/FastString.lhs b/ghc/compiler/utils/FastString.lhs
index 61750aa..661b89e 100644
--- a/ghc/compiler/utils/FastString.lhs
+++ b/ghc/compiler/utils/FastString.lhs
@@ -3,8 +3,18 @@
 %
 \section{Fast strings}
 
-Compact representations of character strings with
-unique identifiers (hash-cons'ish).
+FastString:	A compact, hash-consed, representation of character strings.
+		Comparison is O(1), and you can get a Unique from them.
+		Generated by the FSLIT macro
+		Turn into SDoc with Outputable.ftext
+
+LitString:	Just a wrapper for the Addr# of a C string (Ptr CChar).
+		Practically no operations
+		Outputing them is fast
+		Generated by the SLIT macro
+		Turn into SDoc with Outputable.ptext
+
+Use LitString unless you want the facilities of FastString
 
 \begin{code}
 module FastString
@@ -106,6 +116,7 @@ instance Eq FastString where
   a /= b = case cmpFS a b of { LT -> True;  EQ -> False; GT -> True  }
 
 instance Ord FastString where
+	-- Compares lexicographically, not by unique
     a <= b = case cmpFS a b of { LT -> True;  EQ -> True;  GT -> False }
     a <	 b = case cmpFS a b of { LT -> True;  EQ -> False; GT -> False }
     a >= b = case cmpFS a b of { LT -> False; EQ -> True;  GT -> True  }
@@ -431,8 +442,10 @@ cmpFS (FastString u1# l1# b1#) (FastString u2# l2# b2#) =
     else		    GT
     ))
 
-foreign import ccall "ghc_memcmp" unsafe 
+#ifndef __HADDOCK__
+foreign import ccall unsafe "ghc_memcmp" 
   memcmp :: ByteArray# -> ByteArray# -> Int# -> IO Int
+#endif
 
 -- -----------------------------------------------------------------------------
 -- Outputting 'FastString's
@@ -497,7 +510,6 @@ hPutFS handle (UnicodeStr _ is)
 -- LitStrings, here for convenience only.
 
 type LitString = Ptr ()
--- ToDo: make it a Ptr when we don't have to support 4.08 any more
 
 mkLitString# :: Addr# -> LitString
 mkLitString# a# = Ptr a#