X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Futils%2FUtil.lhs;h=dc4f32ec5e7d7f4dffec59df200cd8fd6db7cf3c;hp=b08f6fab57294cbf96ef0dd655d2a182951a0830;hb=e2e0785eb7f4efd9f7791d913cdfdfd03148cd86;hpb=b6f9d6f2c56074a3f46dbd8635560af5e2f4d420

diff --git a/compiler/utils/Util.lhs b/compiler/utils/Util.lhs
index b08f6fa..dc4f32e 100644
--- a/compiler/utils/Util.lhs
+++ b/compiler/utils/Util.lhs
@@ -66,6 +66,9 @@ module Util (
         -- * Floating point
         readRational,
 
+        -- * read helpers
+        maybeReadFuzzy,
+
         -- * IO-ish utilities
         createDirectoryHierarchy,
         doesDirNameExist,
@@ -81,7 +84,10 @@ module Util (
         Direction(..), reslash,
 
         -- * Utils for defining Data instances
-        abstractConstr, abstractDataType, mkNoRepType
+        abstractConstr, abstractDataType, mkNoRepType,
+
+        -- * Utils for printing C code
+        charToC
     ) where
 
 #include "HsVersions.h"
@@ -106,7 +112,7 @@ import System.Directory ( doesDirectoryExist, createDirectory,
 import System.FilePath
 import System.Time      ( ClockTime )
 
-import Data.Char        ( isUpper, isAlphaNum, isSpace, ord, isDigit )
+import Data.Char        ( isUpper, isAlphaNum, isSpace, chr, ord, isDigit )
 import Data.Ratio       ( (%) )
 import Data.Ord         ( comparing )
 import Data.Bits
@@ -801,9 +807,18 @@ fuzzyLookup user_entered possibilites
                                             poss_str user_entered
                        , distance <= fuzzy_threshold ]
   where
-    -- Work out an approriate match threshold
-    -- (about a quarter of the # of characters the user entered)
-    fuzzy_threshold = max (round $ fromInteger (genericLength user_entered) / (4 :: Rational)) 1
+    -- Work out an approriate match threshold: 
+    -- We report a candidate if its edit distance is <= the threshold, 
+    -- The threshhold is set to about a quarter of the # of characters the user entered
+    -- 	 Length    Threshold
+    --	   1	     0		-- Don't suggest *any* candidates
+    --	   2	     1		-- for single-char identifiers
+    -- 	   3	     1
+    --	   4	     1
+    --	   5	     1
+    --	   6	     2
+    --
+    fuzzy_threshold = truncate $ fromIntegral (length user_entered + 2) / (4 :: Rational)
     mAX_RESULTS = 3
 \end{code}
 
@@ -954,6 +969,17 @@ readRational top_s
 
 
 -----------------------------------------------------------------------------
+-- read helpers
+
+maybeReadFuzzy :: Read a => String -> Maybe a
+maybeReadFuzzy str = case reads str of
+                     [(x, s)]
+                      | all isSpace s ->
+                         Just x
+                     _ ->
+                         Nothing
+
+-----------------------------------------------------------------------------
 -- Create a hierarchy of directories
 
 createDirectoryHierarchy :: FilePath -> IO ()
@@ -1057,3 +1083,22 @@ abstractDataType :: String -> DataType
 abstractDataType n = mkDataType n [abstractConstr n]
 \end{code}
 
+%************************************************************************
+%*                                                                      *
+\subsection[Utils-C]{Utils for printing C code}
+%*                                                                      *
+%************************************************************************
+
+\begin{code}
+charToC :: Word8 -> String
+charToC w = 
+  case chr (fromIntegral w) of
+	'\"' -> "\\\""
+	'\'' -> "\\\'"
+	'\\' -> "\\\\"
+	c | c >= ' ' && c <= '~' -> [c]
+          | otherwise -> ['\\',
+                         chr (ord '0' + ord c `div` 64),
+                         chr (ord '0' + ord c `div` 8 `mod` 8),
+                         chr (ord '0' + ord c         `mod` 8)]
+\end{code}