From 9ef40dc2a0b3e06c8f38ed4c080c4d7dfe579f37 Mon Sep 17 00:00:00 2001
From: Max Bolingbroke <batterseapower@hotmail.com>
Date: Thu, 31 Jul 2008 01:23:53 +0000
Subject: [PATCH] Document FastString and rename strLength to lengthLS

---
 compiler/utils/FastString.lhs |   64 ++++++++++++++++++++++-------------------
 1 file changed, 35 insertions(+), 29 deletions(-)

diff --git a/compiler/utils/FastString.lhs b/compiler/utils/FastString.lhs
index 7d43dc1..cf4e37d 100644
--- a/compiler/utils/FastString.lhs
+++ b/compiler/utils/FastString.lhs
@@ -10,26 +10,30 @@
 -- We always optimise this, otherwise performance of a non-optimised
 -- compiler is severely affected
 
-{-
-FastString:     A compact, hash-consed, representation of character strings.
-                Comparison is O(1), and you can get a Unique from them.
-                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 sLit
-                Turn into SDoc with Outputable.ptext
-
-Use LitString unless you want the facilities of FastString
--}
+-- |
+-- There are two principal string types used internally by GHC:
+--
+-- 'FastString':
+--               * A compact, hash-consed, representation of character strings.
+--               * Comparison is O(1), and you can get a 'Unique.Unique' from them.
+--               * Generated by 'fsLit'.
+--               * Turn into 'Outputable.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 'sLit'.
+--               * Turn into 'Outputable.SDoc' with 'Outputable.ptext'
+--
+-- Use 'LitString' unless you want the facilities of 'FastString'.
 module FastString
        (
         -- * FastStrings
         FastString(..),     -- not abstract, for now.
 
         -- ** Construction
+        fsLit,
         mkFastString,
         mkFastStringBytes,
         mkFastStringByteList,
@@ -68,17 +72,19 @@ module FastString
 
         -- * LitStrings
         LitString,
+        
+        -- ** Construction
+        sLit,
 #if defined(__GLASGOW_HASKELL__)
         mkLitString#,
 #endif
         mkLitString,
+        
+        -- ** Deconstruction
         unpackLitString,
-        strLength,
-
-        ptrStrLength,
-
-        sLit,
-        fsLit,
+        
+        -- ** Operations
+        lengthLS
        ) where
 
 #include "HsVersions.h"
@@ -385,12 +391,12 @@ hashStr (Ptr a#) (I# len#) = loop 0# 0#
 lengthFS :: FastString -> Int
 lengthFS f = n_chars f
 
--- | Returns 'True' if the 'FastString' is Z-encoded
+-- | Returns @True@ if the 'FastString' is Z-encoded
 isZEncoded :: FastString -> Bool
 isZEncoded fs | ZEncoded <- enc fs = True
               | otherwise          = False
 
--- | Returns 'True' if this 'FastString' is not Z-encoded but already has
+-- | Returns @True@ if this 'FastString' is not Z-encoded but already has
 -- a Z-encoding cached (used in producing stats).
 hasZEncoding :: FastString -> Bool
 hasZEncoding (FastString _ _ _ _ enc) =
@@ -401,11 +407,11 @@ hasZEncoding (FastString _ _ _ _ enc) =
         m <- readIORef ref
         return (isJust m)
 
--- | Returns 'True' if the 'FastString' is empty
+-- | Returns @True@ if the 'FastString' is empty
 nullFS :: FastString -> Bool
 nullFS f  =  n_bytes f == 0
 
--- | unpacks and decodes the FastString
+-- | Unpacks and decodes the FastString
 unpackFS :: FastString -> String
 unpackFS (FastString _ n_bytes _ buf enc) =
   inlinePerformIO $ withForeignPtr buf $ \ptr ->
@@ -418,7 +424,7 @@ bytesFS (FastString _ n_bytes _ buf _) =
   inlinePerformIO $ withForeignPtr buf $ \ptr ->
     peekArray n_bytes ptr
 
--- | returns a Z-encoded version of a 'FastString'.  This might be the
+-- | Returns a Z-encoded version of a 'FastString'.  This might be the
 -- original, if it was already Z-encoded.  The first time this
 -- function is applied to a particular 'FastString', the results are
 -- memoized.
@@ -545,8 +551,8 @@ unpackLitString p_ = case pUnbox p_ of
       ch -> if ch `eqFastChar` _CLIT('\0')
             then [] else cBox ch : unpack (n +# _ILIT(1))
 
-strLength :: LitString -> Int
-strLength = ptrStrLength
+lengthLS :: LitString -> Int
+lengthLS = ptrStrLength
 
 -- for now, use a simple String representation
 --no, let's not do that right now - it's work in other places
@@ -559,8 +565,8 @@ mkLitString = id
 unpackLitString :: LitString -> String
 unpackLitString = id
 
-strLength :: LitString -> Int
-strLength = length
+lengthLS :: LitString -> Int
+lengthLS = length
 
 #endif
 
-- 
1.7.10.4