X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Futils%2FUtil.lhs;h=119ae82059b70fa4ba607cc1b30efbbbecffcbf7;hb=97906cfcc30dd591e840921d336fdabeb1b8a315;hp=cb2c5b673ecbfb9491a2adde173e44615b7acb85;hpb=e74cd017fc700e503c8a0b0e94d8b8f9d8c92510;p=ghc-hetmet.git

diff --git a/ghc/compiler/utils/Util.lhs b/ghc/compiler/utils/Util.lhs
index cb2c5b6..119ae82 100644
--- a/ghc/compiler/utils/Util.lhs
+++ b/ghc/compiler/utils/Util.lhs
@@ -1,84 +1,69 @@
 %
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
+% (c) The University of Glasgow 1992-2002
 %
 \section[Util]{Highly random utility functions}
 
 \begin{code}
--- IF_NOT_GHC is meant to make this module useful outside the context of GHC
-#define IF_NOT_GHC(a)
-
 module Util (
-#if NOT_USED
-	-- The Eager monad
-	Eager, thenEager, returnEager, mapEager, appEager, runEager,
-#endif
 
 	-- general list processing
 	zipEqual, zipWithEqual, zipWith3Equal, zipWith4Equal,
         zipLazy, stretchZipWith,
 	mapAndUnzip, mapAndUnzip3,
-	nOfThem, lengthExceeds, isSingleton, only,
+	nOfThem, 
+	lengthExceeds, lengthIs, lengthAtLeast, listLengthCmp, atLength,
+	isSingleton, only,
+	notNull,
+
 	snocView,
 	isIn, isn'tIn,
 
 	-- for-loop
 	nTimes,
 
-	-- maybe-ish
-	unJust,
-
 	-- sorting
-	IF_NOT_GHC(quicksort COMMA stableSortLt COMMA mergesort COMMA)
-	sortLt,
-	IF_NOT_GHC(mergeSort COMMA) naturalMergeSortLe,	-- from Carsten
-	IF_NOT_GHC(naturalMergeSort COMMA mergeSortLe COMMA)
+	sortLt, naturalMergeSortLe,
 
 	-- transitive closures
 	transitiveClosure,
 
 	-- accumulating
-	mapAccumL, mapAccumR, mapAccumB, foldl2, count,
+	mapAccumL, mapAccumR, mapAccumB, 
+	foldl2, count,
+	
+	takeList, dropList, splitAtList,
 
 	-- comparisons
+	eqListBy, equalLength, compareLength,
 	thenCmp, cmpList, prefixMatch, suffixMatch,
 
 	-- strictness
-	seqList, ($!),
+	foldl', seqList,
 
 	-- pairs
-	IF_NOT_GHC(cfst COMMA applyToPair COMMA applyToFst COMMA)
-	IF_NOT_GHC(applyToSnd COMMA foldPair COMMA)
-	unzipWith
-
-	-- I/O
-#if __GLASGOW_HASKELL__ < 402
-	, bracket
-#endif
-
-	, global
-	, myGetProcessID
-
-#if __GLASGOW_HASKELL__ <= 408
-	, catchJust
-	, ioErrors
-	, throwTo
-#endif
+	unzipWith,
 
+	global,
     ) where
 
+#include "../includes/config.h"
 #include "HsVersions.h"
 
-import List		( zipWith4 )
-import Maybe		( Maybe(..) )
-import Panic		( panic )
-import IOExts		( IORef, newIORef, unsafePerformIO )
+import Panic		( panic, trace )
 import FastTypes
+
 #if __GLASGOW_HASKELL__ <= 408
-import Exception	( catchIO, justIoErrors, raiseInThread )
+import EXCEPTION	( catchIO, justIoErrors, raiseInThread )
 #endif
-#ifndef mingw32_TARGET_OS
-import Posix
+import DATA_IOREF	( IORef, newIORef )
+import UNSAFE_IO	( unsafePerformIO )
+
+import qualified List	( elem, notElem )
+
+#ifndef DEBUG
+import List		( zipWith4 )
 #endif
+
 infixr 9 `thenCmp`
 \end{code}
 
@@ -133,18 +118,6 @@ nTimes n f = f . nTimes (n-1) f
 
 %************************************************************************
 %*									*
-\subsection{Maybe-ery}
-%*									*
-%************************************************************************
-
-\begin{code}
-unJust :: String -> Maybe a -> a
-unJust who (Just x) = x
-unJust who Nothing  = panic ("unJust of Nothing, called by " ++ who)
-\end{code}
-
-%************************************************************************
-%*									*
 \subsection[Utils-lists]{General list processing}
 %*									*
 %************************************************************************
@@ -234,15 +207,57 @@ mapAndUnzip3 f (x:xs)
 nOfThem :: Int -> a -> [a]
 nOfThem n thing = replicate n thing
 
+-- 'atLength atLen atEnd ls n' unravels list 'ls' to position 'n';
+-- specification:
+--
+--  atLength atLenPred atEndPred ls n
+--   | n < 0         = atLenPred n
+--   | length ls < n = atEndPred (n - length ls)
+--   | otherwise     = atLenPred (drop n ls)
+--
+atLength :: ([a] -> b)
+         -> (Int -> b)
+         -> [a]
+         -> Int
+         -> b
+atLength atLenPred atEndPred ls n 
+  | n < 0     = atEndPred n 
+  | otherwise = go n ls
+  where
+    go n [] = atEndPred n
+    go 0 ls = atLenPred ls
+    go n (_:xs) = go (n-1) xs
+
+-- special cases.
 lengthExceeds :: [a] -> Int -> Bool
--- (lengthExceeds xs n) is True if   length xs > n
-(x:xs)	`lengthExceeds` n = n < 1 || xs `lengthExceeds` (n - 1)
-[]	`lengthExceeds` n = n < 0
+-- (lengthExceeds xs n) = (length xs > n)
+lengthExceeds = atLength notNull (const False)
+
+lengthAtLeast :: [a] -> Int -> Bool
+lengthAtLeast = atLength notNull (== 0)
+
+lengthIs :: [a] -> Int -> Bool
+lengthIs = atLength null (==0)
+
+listLengthCmp :: [a] -> Int -> Ordering 
+listLengthCmp = atLength atLen atEnd 
+ where
+  atEnd 0      = EQ
+  atEnd x
+   | x > 0     = LT -- not yet seen 'n' elts, so list length is < n.
+   | otherwise = GT
+
+  atLen []     = EQ
+  atLen _      = GT
 
 isSingleton :: [a] -> Bool
 isSingleton [x] = True
 isSingleton  _  = False
 
+notNull :: [a] -> Bool
+notNull [] = False
+notNull _  = True
+
 only :: [a] -> a
 #ifdef DEBUG
 only [a] = a
@@ -281,19 +296,19 @@ isIn msg x ys
   where
     elem i _ []	    = False
     elem i x (y:ys)
-      | i ># _ILIT 100 = panic ("Over-long elem in: " ++ msg)
-      | otherwise	 = x == y || elem (i +# _ILIT(1)) x ys
+      | i ># _ILIT 100 = trace ("Over-long elem in " ++ msg) $
+			 x `List.elem` (y:ys)
+      | otherwise      = x == y || elem (i +# _ILIT(1)) x ys
 
 isn'tIn msg x ys
   = notElem (_ILIT 0) x ys
   where
     notElem i x [] =  True
     notElem i x (y:ys)
-      | i ># _ILIT 100 = panic ("Over-long notElem in: " ++ msg)
-      | otherwise	 =  x /= y && notElem (i +# _ILIT(1)) x ys
-
+      | i ># _ILIT 100 = trace ("Over-long notElem in " ++ msg) $
+		         x `List.notElem` (y:ys)
+      | otherwise      =  x /= y && notElem (i +# _ILIT(1)) x ys
 # endif {- DEBUG -}
-
 \end{code}
 
 %************************************************************************
@@ -330,8 +345,6 @@ Quicksort variant from Lennart's Haskell-library contribution.  This
 is a {\em stable} sort.
 
 \begin{code}
-stableSortLt = sortLt	-- synonym; when we want to highlight stable-ness
-
 sortLt :: (a -> a -> Bool) 		-- Less-than predicate
        -> [a] 				-- Input list
        -> [a]				-- Result list
@@ -513,12 +526,15 @@ generalMergeSort p xs = (balancedFold (generalMerge p) . map (: [])) xs
 generalNaturalMergeSort p [] = []
 generalNaturalMergeSort p xs = (balancedFold (generalMerge p) . group p) xs
 
+#if NOT_USED
 mergeSort, naturalMergeSort :: Ord a => [a] -> [a]
 
 mergeSort = generalMergeSort (<=)
 naturalMergeSort = generalNaturalMergeSort (<=)
 
 mergeSortLe le = generalMergeSort le
+#endif
+
 naturalMergeSortLe le = generalNaturalMergeSort le
 \end{code}
 
@@ -610,6 +626,16 @@ mapAccumB f a b (x:xs) = (a'',b'',y:ys)
 	(a'',b',ys) = mapAccumB f a' b xs
 \end{code}
 
+A strict version of foldl.
+
+\begin{code}
+foldl'        :: (a -> b -> a) -> a -> [b] -> a
+foldl' f z xs = lgo z xs
+	     where
+		lgo z []     =  z
+		lgo z (x:xs) = (lgo $! (f z x)) xs
+\end{code}
+
 A combination of foldl with zip.  It works with equal length lists.
 
 \begin{code}
@@ -627,6 +653,32 @@ count p (x:xs) | p x       = 1 + count p xs
 	       | otherwise = count p xs
 \end{code}
 
+@splitAt@, @take@, and @drop@ but with length of another
+list giving the break-off point:
+
+\begin{code}
+takeList :: [b] -> [a] -> [a]
+takeList [] _ = []
+takeList (_:xs) ls = 
+   case ls of
+     [] -> []
+     (y:ys) -> y : takeList xs ys
+
+dropList :: [b] -> [a] -> [a]
+dropList [] xs    = xs
+dropList _  xs@[] = xs
+dropList (_:xs) (_:ys) = dropList xs ys
+
+
+splitAtList :: [b] -> [a] -> ([a], [a])
+splitAtList [] xs     = ([], xs)
+splitAtList _ xs@[]   = (xs, xs)
+splitAtList (_:xs) (y:ys) = (y:ys', ys'')
+    where
+      (ys', ys'') = splitAtList xs ys
+
+\end{code}
+
 
 %************************************************************************
 %*									*
@@ -635,6 +687,22 @@ count p (x:xs) | p x       = 1 + count p xs
 %************************************************************************
 
 \begin{code}
+eqListBy :: (a->a->Bool) -> [a] -> [a] -> Bool
+eqListBy eq []     []     = True
+eqListBy eq (x:xs) (y:ys) = eq x y && eqListBy eq xs ys
+eqListBy eq xs     ys     = False
+
+equalLength :: [a] -> [b] -> Bool
+equalLength [] []         = True
+equalLength (_:xs) (_:ys) = equalLength xs ys
+equalLength xs    ys      = False
+
+compareLength :: [a] -> [b] -> Ordering
+compareLength [] []         = EQ
+compareLength (_:xs) (_:ys) = compareLength xs ys
+compareLength [] _ys        = LT
+compareLength _xs []        = GT
+
 thenCmp :: Ordering -> Ordering -> Ordering
 {-# INLINE thenCmp #-}
 thenCmp EQ   any = any
@@ -670,14 +738,17 @@ suffixMatch pat str = prefixMatch (reverse pat) (reverse str)
 The following are curried versions of @fst@ and @snd@.
 
 \begin{code}
+#if NOT_USED
 cfst :: a -> b -> a	-- stranal-sem only (Note)
 cfst x y = x
+#endif
 \end{code}
 
 The following provide us higher order functions that, when applied
 to a function, operate on pairs.
 
 \begin{code}
+#if NOT_USED
 applyToPair :: ((a -> c),(b -> d)) -> (a,b) -> (c,d)
 applyToPair (f,g) (x,y) = (f x, g y)
 
@@ -686,6 +757,7 @@ applyToFst f (x,y) = (f x,y)
 
 applyToSnd :: (b -> d) -> (a,b) -> (a,d)
 applyToSnd f (x,y) = (x,f y)
+#endif
 
 foldPair :: (a->a->a,b->b->b) -> (a,b) -> [(a,b)] -> (a,b)
 foldPair fg ab [] = ab
@@ -699,29 +771,9 @@ unzipWith f pairs = map ( \ (a, b) -> f a b ) pairs
 \end{code}
 
 \begin{code}
-#if __HASKELL1__ > 4
 seqList :: [a] -> b -> b
-#else
-seqList :: (Eval a) => [a] -> b -> b
-#endif
 seqList [] b = b
 seqList (x:xs) b = x `seq` seqList xs b
-
-#if __HASKELL1__ <= 4
-($!)    :: (Eval a) => (a -> b) -> a -> b
-f $! x  = x `seq` f x
-#endif
-\end{code}
-
-\begin{code}
-#if __GLASGOW_HASKELL__ < 402
-bracket :: IO a -> (a -> IO b) -> (a -> IO c) -> IO c
-bracket before after thing = do
-  a <- before 
-  r <- (thing a) `catch` (\err -> after a >> fail err)
-  after a
-  return r
-#endif
 \end{code}
 
 Global variables:
@@ -730,20 +782,3 @@ Global variables:
 global :: a -> IORef a
 global a = unsafePerformIO (newIORef a)
 \end{code}
-
-Compatibility stuff:
-
-\begin{code}
-#if __GLASGOW_HASKELL__ <= 408
-catchJust = catchIO
-ioErrors  = justIoErrors
-throwTo   = raiseInThread
-#endif
-
-#ifdef mingw32_TARGET_OS
-foreign import "_getpid" myGetProcessID :: IO Int 
-#else
-myGetProcessID :: IO Int
-myGetProcessID = Posix.getProcessID
-#endif
-\end{code}