{-
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
+ Generated by fsLit
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
+ Generated by sLit
Turn into SDoc with Outputable.ptext
Use LitString unless you want the facilities of FastString
LitString,
#if defined(__GLASGOW_HASKELL__)
mkLitString#,
-#else
- mkLitString,
#endif
+ mkLitString,
unpackLitString,
strLength,
- ptrStrLength
+ ptrStrLength,
+
+ sLit,
+ fsLit,
) where
--- This #define suppresses the "import FastString" that
--- HsVersions otherwise produces
-#define COMPILING_FAST_STRING
#include "HsVersions.h"
import Encoding
import System.IO.Unsafe ( unsafePerformIO )
import Data.IORef ( IORef, newIORef, readIORef, writeIORef )
import Data.Maybe ( isJust )
-#if !defined(__GLASGOW_HASKELL__)
import Data.Char ( ord )
-#endif
import GHC.IOBase ( IO(..) )
import GHC.Ptr ( Ptr(..) )
+#if defined(__GLASGOW_HASKELL__)
+import GHC.Base ( unpackCString# )
+#endif
#define hASH_TBL_SIZE 4091
#define hASH_TBL_SIZE_UNBOXED 4091#
#if defined(__GLASGOW_HASKELL__)
mkLitString# :: Addr# -> LitString
mkLitString# a# = Ptr a#
-#else
+#endif
--can/should we use FastTypes here?
--Is this likely to be memory-preserving if only used on constant strings?
--should we inline it? If lucky, that would make a CAF that wouldn't
loop n (c:cs) = do
pokeByteOff p n (fromIntegral (ord c) :: Word8)
loop (1+n) cs
+ -- XXX GHC isn't smart enough to know that we have already covered
+ -- this case.
+ loop _ [] = panic "mkLitString"
loop 0 s
return p
)
-#endif
unpackLitString :: LitString -> String
unpackLitString p_ = case pUnbox p_ of
#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ <= 602
peekCAStringLen = peekCStringLen
#endif
+
+{-# NOINLINE sLit #-}
+sLit :: String -> LitString
+sLit x = mkLitString x
+
+{-# NOINLINE fsLit #-}
+fsLit :: String -> FastString
+fsLit x = mkFastString x
+
+{-# RULES "slit"
+ forall x . sLit (unpackCString# x) = mkLitString# x #-}
+{-# RULES "fslit"
+ forall x . fsLit (unpackCString# x) = mkFastString# x #-}
\end{code}