%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The University of Glasgow 1992-2002
%
\section[Util]{Highly random utility functions}
\begin{code}
-#if defined(COMPILING_GHC)
-# include "HsVersions.h"
-# define IF_NOT_GHC(a) {--}
-#else
-# define panic error
-# define TAG_ _CMP_TAG
-# define LT_ _LT
-# define EQ_ _EQ
-# define GT_ _GT
-# define GT__ _
-# define tagCmp_ _tagCmp
-# define FAST_STRING String
-# define ASSERT(x) {-nothing-}
-# define IF_NOT_GHC(a) a
-# define COMMA ,
-#endif
-
-#ifndef __GLASGOW_HASKELL__
-# undef TAG_
-# undef LT_
-# undef EQ_
-# undef GT_
-# undef tagCmp_
-#endif
-
module Util (
- -- Haskell-version support
-#ifndef __GLASGOW_HASKELL__
- tagCmp_,
- TAG_(..),
-#endif
+
-- general list processing
- IF_NOT_GHC(forall COMMA exists COMMA)
zipEqual, zipWithEqual, zipWith3Equal, zipWith4Equal,
- zipLazy,
+ zipLazy, stretchZipWith,
+ mapFst, mapSnd,
mapAndUnzip, mapAndUnzip3,
- nOfThem, lengthExceeds, isSingleton,
- startsWith, endsWith,
-#if defined(COMPILING_GHC)
- isIn, isn'tIn,
-#endif
+ nOfThem, filterOut,
+ lengthExceeds, lengthIs, lengthAtLeast, listLengthCmp, atLength,
+ isSingleton, only, singleton,
+ notNull, snocView,
- -- association lists
- assoc,
+ isIn, isn'tIn,
- -- duplicate handling
- hasNoDups, equivClasses, runs, removeDups,
+ -- for-loop
+ nTimes,
-- 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)
+ sortLe, sortWith,
-- transitive closures
transitiveClosure,
-- accumulating
- mapAccumL, mapAccumR, mapAccumB,
+ mapAccumL, mapAccumR, mapAccumB,
+ foldl2, count, all2,
+
+ takeList, dropList, splitAtList, split,
-- comparisons
- Ord3(..), thenCmp, cmpList,
- IF_NOT_GHC(cmpString COMMA)
- cmpPString,
+ isEqual, eqListBy, equalLength, compareLength,
+ thenCmp, cmpList, prefixMatch, suffixMatch, maybePrefixMatch,
+ removeSpaces,
+
+ -- strictness
+ foldl', seqList,
-- pairs
- IF_NOT_GHC(cfst COMMA applyToPair COMMA applyToFst COMMA)
- IF_NOT_GHC(applyToSnd COMMA foldPair COMMA)
- unzipWith
+ unzipWith,
+
+ global, consIORef,
+
+ -- module names
+ looksLikeModuleName,
+
+ toArgs,
+
+ -- Floating point stuff
+ readRational,
+
+ -- IO-ish utilities
+ createDirectoryHierarchy,
+ doesDirNameExist,
+ modificationTimeIfExists,
+
+ later, handleDyn, handle,
+
+ -- Filename utils
+ Suffix,
+ splitFilename, suffixOf, basenameOf, joinFileExt,
+ splitFilenameDir, joinFileName,
+ splitFilename3,
+ splitLongestPrefix,
+ replaceFilenameSuffix, directoryOf, filenameOf,
+ replaceFilenameDirectory,
+ escapeSpaces, isPathSeparator,
+ parseSearchPath,
+ normalisePath, platformPath, pgmPath,
+ ) where
- -- error handling
-#if defined(COMPILING_GHC)
- , panic, panic#, pprPanic, pprPanic#, pprError, pprTrace
- , assertPanic
-#endif {- COMPILING_GHC -}
+#include "HsVersions.h"
- ) where
+import Panic ( panic, trace )
+import FastTypes
-#if defined(COMPILING_GHC)
+import EXCEPTION ( Exception(..), finally, throwDyn, catchDyn, throw )
+import qualified EXCEPTION as Exception
+import DYNAMIC ( Typeable )
+import DATA_IOREF ( IORef, newIORef )
+import UNSAFE_IO ( unsafePerformIO )
+import DATA_IOREF ( readIORef, writeIORef )
-CHK_Ubiq() -- debugging consistency check
+import qualified List ( elem, notElem )
-import Pretty
+#ifndef DEBUG
+import List ( zipWith4 )
#endif
+import Monad ( when )
+import IO ( catch, isDoesNotExistError )
+import Directory ( doesDirectoryExist, createDirectory )
+import Char ( isUpper, isAlphaNum, isSpace, ord, isDigit )
+import Ratio ( (%) )
+import Time ( ClockTime )
+import Directory ( getModificationTime )
+
infixr 9 `thenCmp`
\end{code}
%************************************************************************
%* *
-\subsection[Utils-version-support]{Functions to help pre-1.2 versions of (non-Glasgow) Haskell}
+\subsection{The Eager monad}
%* *
%************************************************************************
-This is our own idea:
+The @Eager@ monad is just an encoding of continuation-passing style,
+used to allow you to express "do this and then that", mainly to avoid
+space leaks. It's done with a type synonym to save bureaucracy.
+
\begin{code}
-#ifndef __GLASGOW_HASKELL__
-data TAG_ = LT_ | EQ_ | GT_
+#if NOT_USED
+
+type Eager ans a = (a -> ans) -> ans
+
+runEager :: Eager a a -> a
+runEager m = m (\x -> x)
+
+appEager :: Eager ans a -> (a -> ans) -> ans
+appEager m cont = m cont
+
+thenEager :: Eager ans a -> (a -> Eager ans b) -> Eager ans b
+thenEager m k cont = m (\r -> k r cont)
-tagCmp_ :: Ord a => a -> a -> TAG_
-tagCmp_ a b = if a == b then EQ_ else if a < b then LT_ else GT_
+returnEager :: a -> Eager ans a
+returnEager v cont = cont v
+
+mapEager :: (a -> Eager ans b) -> [a] -> Eager ans [b]
+mapEager f [] = returnEager []
+mapEager f (x:xs) = f x `thenEager` \ y ->
+ mapEager f xs `thenEager` \ ys ->
+ returnEager (y:ys)
#endif
\end{code}
%************************************************************************
%* *
-\subsection[Utils-lists]{General list processing}
+\subsection{A for loop}
%* *
%************************************************************************
-Quantifiers are not standard in Haskell. The following fill in the gap.
-
\begin{code}
-forall :: (a -> Bool) -> [a] -> Bool
-forall pred [] = True
-forall pred (x:xs) = pred x && forall pred xs
+-- Compose a function with itself n times. (nth rather than twice)
+nTimes :: Int -> (a -> a) -> (a -> a)
+nTimes 0 _ = id
+nTimes 1 f = f
+nTimes n f = f . nTimes (n-1) f
+\end{code}
-exists :: (a -> Bool) -> [a] -> Bool
-exists pred [] = False
-exists pred (x:xs) = pred x || exists pred xs
+%************************************************************************
+%* *
+\subsection[Utils-lists]{General list processing}
+%* *
+%************************************************************************
+
+\begin{code}
+filterOut :: (a->Bool) -> [a] -> [a]
+-- Like filter, only reverses the sense of the test
+filterOut p [] = []
+filterOut p (x:xs) | p x = filterOut p xs
+ | otherwise = x : filterOut p xs
\end{code}
A paranoid @zip@ (and some @zipWith@ friends) that checks the lists
zipLazy (x:xs) ~(y:ys) = (x,y) : zipLazy xs ys
\end{code}
+
\begin{code}
+stretchZipWith :: (a -> Bool) -> b -> (a->b->c) -> [a] -> [b] -> [c]
+-- (stretchZipWith p z f xs ys) stretches ys by inserting z in
+-- the places where p returns *True*
+
+stretchZipWith p z f [] ys = []
+stretchZipWith p z f (x:xs) ys
+ | p x = f x z : stretchZipWith p z f xs ys
+ | otherwise = case ys of
+ [] -> []
+ (y:ys) -> f x y : stretchZipWith p z f xs ys
+\end{code}
+
+
+\begin{code}
+mapFst :: (a->c) -> [(a,b)] -> [(c,b)]
+mapSnd :: (b->c) -> [(a,b)] -> [(a,c)]
+
+mapFst f xys = [(f x, y) | (x,y) <- xys]
+mapSnd f xys = [(x, f y) | (x,y) <- xys]
+
mapAndUnzip :: (a -> (b, c)) -> [a] -> ([b], [c])
mapAndUnzip f [] = ([],[])
\begin{code}
nOfThem :: Int -> a -> [a]
-nOfThem n thing = take n (repeat thing)
+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) = (length xs > n)
+lengthExceeds = atLength notNull (const False)
-[] `lengthExceeds` n = 0 > n
-(x:xs) `lengthExceeds` n = (1 > n) || (xs `lengthExceeds` (n - 1))
+lengthAtLeast :: [a] -> Int -> Bool
+lengthAtLeast = atLength notNull (== 0)
-isSingleton :: [a] -> Bool
+lengthIs :: [a] -> Int -> Bool
+lengthIs = atLength null (==0)
-isSingleton [x] = True
-isSingleton _ = False
+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
-startsWith, endsWith :: String -> String -> Maybe String
+singleton :: a -> [a]
+singleton x = [x]
-startsWith [] str = Just str
-startsWith (c:cs) (s:ss)
- = if c /= s then Nothing else startsWith cs ss
+isSingleton :: [a] -> Bool
+isSingleton [x] = True
+isSingleton _ = False
-endsWith cs ss
- = case (startsWith (reverse cs) (reverse ss)) of
- Nothing -> Nothing
- Just rs -> Just (reverse rs)
+notNull :: [a] -> Bool
+notNull [] = False
+notNull _ = True
+
+snocView :: [a] -> Maybe ([a],a)
+ -- Split off the last element
+snocView [] = Nothing
+snocView xs = go [] xs
+ where
+ -- Invariant: second arg is non-empty
+ go acc [x] = Just (reverse acc, x)
+ go acc (x:xs) = go (x:acc) xs
+
+only :: [a] -> a
+#ifdef DEBUG
+only [a] = a
+#else
+only (a:_) = a
+#endif
\end{code}
Debugging/specialising versions of \tr{elem} and \tr{notElem}
+
\begin{code}
-#if defined(COMPILING_GHC)
isIn, isn'tIn :: (Eq a) => String -> a -> [a] -> Bool
# ifndef DEBUG
notElem__ x [] = True
notElem__ x (y:ys) = x /= y && notElem__ x ys
-# else {- DEBUG -}
+# else /* DEBUG */
isIn msg x ys
- = elem ILIT(0) x ys
+ = elem (_ILIT 0) x ys
where
elem i _ [] = False
elem i x (y:ys)
- | i _GE_ ILIT(100) = panic ("Over-long elem in: " ++ msg)
- | otherwise = x == y || elem (i _ADD_ 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
+ = notElem (_ILIT 0) x ys
where
notElem i x [] = True
notElem i x (y:ys)
- | i _GE_ ILIT(100) = panic ("Over-long notElem in: " ++ msg)
- | otherwise = x /= y && notElem (i _ADD_ ILIT(1)) x ys
-
-# endif {- DEBUG -}
-
-#endif {- COMPILING_GHC -}
-\end{code}
-
-%************************************************************************
-%* *
-\subsection[Utils-assoc]{Association lists}
-%* *
-%************************************************************************
-
-See also @assocMaybe@ and @mkLookupFun@ in module @Maybes@.
-
-\begin{code}
-assoc :: (Eq a) => String -> [(a, b)] -> a -> b
-
-assoc crash_msg lst key
- = if (null res)
- then panic ("Failed in assoc: " ++ crash_msg)
- else head res
- where res = [ val | (key', val) <- lst, key == key']
-\end{code}
-
-%************************************************************************
-%* *
-\subsection[Utils-dups]{Duplicate-handling}
-%* *
-%************************************************************************
-
-\begin{code}
-hasNoDups :: (Eq a) => [a] -> Bool
-
-hasNoDups xs = f [] xs
- where
- f seen_so_far [] = True
- f seen_so_far (x:xs) = if x `is_elem` seen_so_far then
- False
- else
- f (x:seen_so_far) xs
-
-#if defined(COMPILING_GHC)
- is_elem = isIn "hasNoDups"
-#else
- is_elem = elem
-#endif
-\end{code}
-
-\begin{code}
-equivClasses :: (a -> a -> TAG_) -- Comparison
- -> [a]
- -> [[a]]
-
-equivClasses cmp stuff@[] = []
-equivClasses cmp stuff@[item] = [stuff]
-equivClasses cmp items
- = runs eq (sortLt lt items)
- where
- eq a b = case cmp a b of { EQ_ -> True; _ -> False }
- lt a b = case cmp a b of { LT_ -> True; _ -> False }
-\end{code}
-
-The first cases in @equivClasses@ above are just to cut to the point
-more quickly...
-
-@runs@ groups a list into a list of lists, each sublist being a run of
-identical elements of the input list. It is passed a predicate @p@ which
-tells when two elements are equal.
-
-\begin{code}
-runs :: (a -> a -> Bool) -- Equality
- -> [a]
- -> [[a]]
-
-runs p [] = []
-runs p (x:xs) = case (span (p x) xs) of
- (first, rest) -> (x:first) : (runs p rest)
-\end{code}
-
-\begin{code}
-removeDups :: (a -> a -> TAG_) -- Comparison function
- -> [a]
- -> ([a], -- List with no duplicates
- [[a]]) -- List of duplicate groups. One representative from
- -- each group appears in the first result
-
-removeDups cmp [] = ([], [])
-removeDups cmp [x] = ([x],[])
-removeDups cmp xs
- = case (mapAccumR collect_dups [] (equivClasses cmp xs)) of { (dups, xs') ->
- (xs', dups) }
- where
- collect_dups dups_so_far [x] = (dups_so_far, x)
- collect_dups dups_so_far dups@(x:xs) = (dups:dups_so_far, x)
-\end{code}
-
-%************************************************************************
-%* *
-\subsection[Utils-sorting]{Sorting}
-%* *
-%************************************************************************
-
-%************************************************************************
-%* *
-\subsubsection[Utils-quicksorting]{Quicksorts}
-%* *
-%************************************************************************
-
-\begin{code}
--- tail-recursive, etc., "quicker sort" [as per Meira thesis]
-quicksort :: (a -> a -> Bool) -- Less-than predicate
- -> [a] -- Input list
- -> [a] -- Result list in increasing order
-
-quicksort lt [] = []
-quicksort lt [x] = [x]
-quicksort lt (x:xs) = split x [] [] xs
- where
- split x lo hi [] = quicksort lt lo ++ (x : quicksort lt hi)
- split x lo hi (y:ys) | y `lt` x = split x (y:lo) hi ys
- | True = split x lo (y:hi) ys
-\end{code}
-
-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
-
-sortLt lt l = qsort lt l []
-
--- qsort is stable and does not concatenate.
-qsort :: (a -> a -> Bool) -- Less-than predicate
- -> [a] -- xs, Input list
- -> [a] -- r, Concatenate this list to the sorted input list
- -> [a] -- Result = sort xs ++ r
-
-qsort lt [] r = r
-qsort lt [x] r = x:r
-qsort lt (x:xs) r = qpart lt x xs [] [] r
-
--- qpart partitions and sorts the sublists
--- rlt contains things less than x,
--- rge contains the ones greater than or equal to x.
--- Both have equal elements reversed with respect to the original list.
-
-qpart lt x [] rlt rge r =
- -- rlt and rge are in reverse order and must be sorted with an
- -- anti-stable sorting
- rqsort lt rlt (x : rqsort lt rge r)
-
-qpart lt x (y:ys) rlt rge r =
- if lt y x then
- -- y < x
- qpart lt x ys (y:rlt) rge r
- else
- -- y >= x
- qpart lt x ys rlt (y:rge) r
-
--- rqsort is as qsort but anti-stable, i.e. reverses equal elements
-rqsort lt [] r = r
-rqsort lt [x] r = x:r
-rqsort lt (x:xs) r = rqpart lt x xs [] [] r
-
-rqpart lt x [] rle rgt r =
- qsort lt rle (x : qsort lt rgt r)
-
-rqpart lt x (y:ys) rle rgt r =
- if lt x y then
- -- y > x
- rqpart lt x ys rle (y:rgt) r
- else
- -- y <= x
- rqpart lt x ys (y:rle) rgt r
-\end{code}
-
-%************************************************************************
-%* *
-\subsubsection[Utils-dull-mergesort]{A rather dull mergesort}
-%* *
-%************************************************************************
-
-\begin{code}
-mergesort :: (a -> a -> TAG_) -> [a] -> [a]
-
-mergesort cmp xs = merge_lists (split_into_runs [] xs)
- where
- a `le` b = case cmp a b of { LT_ -> True; EQ_ -> True; GT__ -> False }
- a `ge` b = case cmp a b of { LT_ -> False; EQ_ -> True; GT__ -> True }
-
- split_into_runs [] [] = []
- split_into_runs run [] = [run]
- split_into_runs [] (x:xs) = split_into_runs [x] xs
- split_into_runs [r] (x:xs) | x `ge` r = split_into_runs [r,x] xs
- split_into_runs rl@(r:rs) (x:xs) | x `le` r = split_into_runs (x:rl) xs
- | True = rl : (split_into_runs [x] xs)
-
- merge_lists [] = []
- merge_lists (x:xs) = merge x (merge_lists xs)
-
- merge [] ys = ys
- merge xs [] = xs
- merge xl@(x:xs) yl@(y:ys)
- = case cmp x y of
- EQ_ -> x : y : (merge xs ys)
- LT_ -> x : (merge xs yl)
- GT__ -> y : (merge xl 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}
%************************************************************************
\begin{code}
group :: (a -> a -> Bool) -> [a] -> [[a]]
+-- Given a <= function, group finds maximal contiguous up-runs
+-- or down-runs in the input list.
+-- It's stable, in the sense that it never re-orders equal elements
+--
+-- Date: Mon, 12 Feb 1996 15:09:41 +0000
+-- From: Andy Gill <andy@dcs.gla.ac.uk>
+-- Here is a `better' definition of group.
-{-
-Date: Mon, 12 Feb 1996 15:09:41 +0000
-From: Andy Gill <andy@dcs.gla.ac.uk>
-
-Here is a `better' definition of group.
--}
group p [] = []
group p (x:xs) = group' xs x x (x :)
where
group' [] _ _ s = [s []]
group' (x:xs) x_min x_max s
- | not (x `p` x_max) = group' xs x_min x (s . (x :))
- | x `p` x_min = group' xs x x_max ((x :) . s)
+ | x_max `p` x = group' xs x_min x (s . (x :))
+ | not (x_min `p` x) = group' xs x x_max ((x :) . s)
| otherwise = s [] : group' xs x x (x :)
-
--- This one works forwards *and* backwards, as well as also being
--- faster that the one in Util.lhs.
-
-{- ORIG:
-group p [] = [[]]
-group p (x:xs) =
- let ((h1:t1):tt1) = group p xs
- (t,tt) = if null xs then ([],[]) else
- if x `p` h1 then (h1:t1,tt1) else
- ([], (h1:t1):tt1)
- in ((x:t):tt)
--}
+ -- NB: the 'not' is essential for stablity
+ -- x `p` x_min would reverse equal elements
generalMerge :: (a -> a -> Bool) -> [a] -> [a] -> [a]
generalMerge p xs [] = xs
balancedFold' f (x:y:xs) = f x y : balancedFold' f xs
balancedFold' f xs = xs
-generalMergeSort p [] = []
-generalMergeSort p xs = (balancedFold (generalMerge p) . map (: [])) xs
-
generalNaturalMergeSort p [] = []
generalNaturalMergeSort p xs = (balancedFold (generalMerge p) . group p) xs
+#if NOT_USED
+generalMergeSort p [] = []
+generalMergeSort p xs = (balancedFold (generalMerge p) . map (: [])) xs
+
mergeSort, naturalMergeSort :: Ord a => [a] -> [a]
mergeSort = generalMergeSort (<=)
naturalMergeSort = generalNaturalMergeSort (<=)
mergeSortLe le = generalMergeSort le
-naturalMergeSortLe le = generalNaturalMergeSort le
+#endif
+
+sortLe :: (a->a->Bool) -> [a] -> [a]
+sortLe le = generalNaturalMergeSort le
+
+sortWith :: Ord b => (a->b) -> [a] -> [a]
+sortWith get_key xs = sortLe le xs
+ where
+ x `le` y = get_key x < get_key y
\end{code}
%************************************************************************
(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}
+foldl2 :: (acc -> a -> b -> acc) -> acc -> [a] -> [b] -> acc
+foldl2 k z [] [] = z
+foldl2 k z (a:as) (b:bs) = foldl2 k (k z a b) as bs
+
+all2 :: (a -> b -> Bool) -> [a] -> [b] -> Bool
+-- True if the lists are the same length, and
+-- all corresponding elements satisfy the predicate
+all2 p [] [] = True
+all2 p (x:xs) (y:ys) = p x y && all2 p xs ys
+all2 p xs ys = False
+\end{code}
+
+Count the number of times a predicate is true
+
+\begin{code}
+count :: (a -> Bool) -> [a] -> Int
+count p [] = 0
+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
+
+split :: Char -> String -> [String]
+split c s = case rest of
+ [] -> [chunk]
+ _:rest -> chunk : split c rest
+ where (chunk, rest) = break (==c) s
+\end{code}
+
+
%************************************************************************
%* *
\subsection[Utils-comparison]{Comparisons}
%* *
%************************************************************************
-See also @tagCmp_@ near the versions-compatibility section.
-
-The Ord3 class will be subsumed into Ord in Haskell 1.3.
-
\begin{code}
-class Ord3 a where
- cmp :: a -> a -> TAG_
+isEqual :: Ordering -> Bool
+-- Often used in (isEqual (a `compare` b))
+isEqual GT = False
+isEqual EQ = True
+isEqual LT = False
-thenCmp :: TAG_ -> TAG_ -> TAG_
+thenCmp :: Ordering -> Ordering -> Ordering
{-# INLINE thenCmp #-}
-thenCmp EQ_ any = any
+thenCmp EQ any = any
thenCmp other any = other
-cmpList :: (a -> a -> TAG_) -> [a] -> [a] -> TAG_
- -- `cmpList' uses a user-specified comparer
-
-cmpList cmp [] [] = EQ_
-cmpList cmp [] _ = LT_
-cmpList cmp _ [] = GT_
-cmpList cmp (a:as) (b:bs)
- = case cmp a b of { EQ_ -> cmpList cmp as bs; xxx -> xxx }
-\end{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
-\begin{code}
-instance Ord3 a => Ord3 [a] where
- cmp [] [] = EQ_
- cmp (x:xs) [] = GT_
- cmp [] (y:ys) = LT_
- cmp (x:xs) (y:ys) = (x `cmp` y) `thenCmp` (xs `cmp` ys)
-
-instance Ord3 a => Ord3 (Maybe a) where
- cmp Nothing Nothing = EQ_
- cmp Nothing (Just y) = LT_
- cmp (Just x) Nothing = GT_
- cmp (Just x) (Just y) = x `cmp` y
-
-instance Ord3 Int where
- cmp a b | a < b = LT_
- | a > b = GT_
- | otherwise = EQ_
-\end{code}
+equalLength :: [a] -> [b] -> Bool
+equalLength [] [] = True
+equalLength (_:xs) (_:ys) = equalLength xs ys
+equalLength xs ys = False
-\begin{code}
-cmpString :: String -> String -> TAG_
+compareLength :: [a] -> [b] -> Ordering
+compareLength [] [] = EQ
+compareLength (_:xs) (_:ys) = compareLength xs ys
+compareLength [] _ys = LT
+compareLength _xs [] = GT
-cmpString [] [] = EQ_
-cmpString (x:xs) (y:ys) = if x == y then cmpString xs ys
- else if x < y then LT_
- else GT_
-cmpString [] ys = LT_
-cmpString xs [] = GT_
+cmpList :: (a -> a -> Ordering) -> [a] -> [a] -> Ordering
+ -- `cmpList' uses a user-specified comparer
-cmpString _ _ = panic# "cmpString"
+cmpList cmp [] [] = EQ
+cmpList cmp [] _ = LT
+cmpList cmp _ [] = GT
+cmpList cmp (a:as) (b:bs)
+ = case cmp a b of { EQ -> cmpList cmp as bs; xxx -> xxx }
\end{code}
\begin{code}
-cmpPString :: FAST_STRING -> FAST_STRING -> TAG_
-
-cmpPString x y
- = case (_tagCmp x y) of { _LT -> LT_ ; _EQ -> EQ_ ; _GT -> GT_ }
+prefixMatch :: Eq a => [a] -> [a] -> Bool
+prefixMatch [] _str = True
+prefixMatch _pat [] = False
+prefixMatch (p:ps) (s:ss) | p == s = prefixMatch ps ss
+ | otherwise = False
+
+maybePrefixMatch :: String -> String -> Maybe String
+maybePrefixMatch [] rest = Just rest
+maybePrefixMatch (_:_) [] = Nothing
+maybePrefixMatch (p:pat) (r:rest)
+ | p == r = maybePrefixMatch pat rest
+ | otherwise = Nothing
+
+suffixMatch :: Eq a => [a] -> [a] -> Bool
+suffixMatch pat str = prefixMatch (reverse pat) (reverse str)
+
+removeSpaces :: String -> String
+removeSpaces = reverse . dropWhile isSpace . reverse . dropWhile isSpace
\end{code}
%************************************************************************
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)
applyToSnd :: (b -> d) -> (a,b) -> (a,d)
applyToSnd f (x,y) = (x,f y)
-
-foldPair :: (a->a->a,b->b->b) -> (a,b) -> [(a,b)] -> (a,b)
-foldPair fg ab [] = ab
-foldPair fg@(f,g) ab ((a,b):abs) = (f a u,g b v)
- where (u,v) = foldPair fg ab abs
+#endif
\end{code}
\begin{code}
unzipWith f pairs = map ( \ (a, b) -> f a b ) pairs
\end{code}
-%************************************************************************
-%* *
-\subsection[Utils-errors]{Error handling}
-%* *
-%************************************************************************
+\begin{code}
+seqList :: [a] -> b -> b
+seqList [] b = b
+seqList (x:xs) b = x `seq` seqList xs b
+\end{code}
+
+Global variables:
\begin{code}
-#if defined(COMPILING_GHC)
-panic x = error ("panic! (the `impossible' happened):\n\t"
- ++ x ++ "\n\n"
- ++ "Please report it as a compiler bug "
- ++ "to glasgow-haskell-bugs@dcs.glasgow.ac.uk.\n\n" )
+global :: a -> IORef a
+global a = unsafePerformIO (newIORef a)
+\end{code}
-pprPanic heading pretty_msg = panic (heading++(ppShow 80 pretty_msg))
-pprError heading pretty_msg = error (heading++(ppShow 80 pretty_msg))
-pprTrace heading pretty_msg = trace (heading++(ppShow 80 pretty_msg))
+\begin{code}
+consIORef :: IORef [a] -> a -> IO ()
+consIORef var x = do
+ xs <- readIORef var
+ writeIORef var (x:xs)
+\end{code}
--- #-versions because panic can't return an unboxed int, and that's
--- what TAG_ is with GHC at the moment. Ugh. (Simon)
--- No, man -- Too Beautiful! (Will)
+Module names:
-panic# :: String -> TAG_
-panic# s = case (panic s) of () -> EQ_
+\begin{code}
+looksLikeModuleName [] = False
+looksLikeModuleName (c:cs) = isUpper c && go cs
+ where go [] = True
+ go ('.':cs) = looksLikeModuleName cs
+ go (c:cs) = (isAlphaNum c || c == '_') && go cs
+\end{code}
-pprPanic# heading pretty_msg = panic# (heading++(ppShow 80 pretty_msg))
+Akin to @Prelude.words@, but sensitive to dquoted entities treating
+them as single words.
-assertPanic :: String -> Int -> a
-assertPanic file line = panic ("ASSERT failed! file "++file++", line "++show line)
+\begin{code}
+toArgs :: String -> [String]
+toArgs "" = []
+toArgs s =
+ case break (\ ch -> isSpace ch || ch == '"') (dropWhile isSpace s) of -- "
+ (w,aft) ->
+ (\ ws -> if null w then ws else w : ws) $
+ case aft of
+ [] -> []
+ (x:xs)
+ | x /= '"' -> toArgs xs
+ | otherwise ->
+ case lex aft of
+ ((str,rs):_) -> stripQuotes str : toArgs rs
+ _ -> [aft]
+ where
+ -- strip away dquotes; assume first and last chars contain quotes.
+ stripQuotes :: String -> String
+ stripQuotes ('"':xs) = init xs
+ stripQuotes xs = xs
+\end{code}
-#endif {- COMPILING_GHC -}
+-- -----------------------------------------------------------------------------
+-- Floats
+
+\begin{code}
+readRational__ :: ReadS Rational -- NB: doesn't handle leading "-"
+readRational__ r = do
+ (n,d,s) <- readFix r
+ (k,t) <- readExp s
+ return ((n%1)*10^^(k-d), t)
+ where
+ readFix r = do
+ (ds,s) <- lexDecDigits r
+ (ds',t) <- lexDotDigits s
+ return (read (ds++ds'), length ds', t)
+
+ readExp (e:s) | e `elem` "eE" = readExp' s
+ readExp s = return (0,s)
+
+ readExp' ('+':s) = readDec s
+ readExp' ('-':s) = do
+ (k,t) <- readDec s
+ return (-k,t)
+ readExp' s = readDec s
+
+ readDec s = do
+ (ds,r) <- nonnull isDigit s
+ return (foldl1 (\n d -> n * 10 + d) [ ord d - ord '0' | d <- ds ],
+ r)
+
+ lexDecDigits = nonnull isDigit
+
+ lexDotDigits ('.':s) = return (span isDigit s)
+ lexDotDigits s = return ("",s)
+
+ nonnull p s = do (cs@(_:_),t) <- return (span p s)
+ return (cs,t)
+
+readRational :: String -> Rational -- NB: *does* handle a leading "-"
+readRational top_s
+ = case top_s of
+ '-' : xs -> - (read_me xs)
+ xs -> read_me xs
+ where
+ read_me s
+ = case (do { (x,"") <- readRational__ s ; return x }) of
+ [x] -> x
+ [] -> error ("readRational: no parse:" ++ top_s)
+ _ -> error ("readRational: ambiguous parse:" ++ top_s)
+
+
+-----------------------------------------------------------------------------
+-- Create a hierarchy of directories
+
+createDirectoryHierarchy :: FilePath -> IO ()
+createDirectoryHierarchy dir = do
+ b <- doesDirectoryExist dir
+ when (not b) $ do
+ createDirectoryHierarchy (directoryOf dir)
+ createDirectory dir
+
+-----------------------------------------------------------------------------
+-- Verify that the 'dirname' portion of a FilePath exists.
+--
+doesDirNameExist :: FilePath -> IO Bool
+doesDirNameExist fpath = doesDirectoryExist (directoryOf fpath)
+
+-- -----------------------------------------------------------------------------
+-- Exception utils
+
+later = flip finally
+
+handleDyn :: Typeable ex => (ex -> IO a) -> IO a -> IO a
+handleDyn = flip catchDyn
+
+handle :: (Exception -> IO a) -> IO a -> IO a
+#if __GLASGOW_HASKELL__ < 501
+handle = flip Exception.catchAllIO
+#else
+handle h f = f `Exception.catch` \e -> case e of
+ ExitException _ -> throw e
+ _ -> h e
+#endif
+
+-- --------------------------------------------------------------
+-- check existence & modification time at the same time
+
+modificationTimeIfExists :: FilePath -> IO (Maybe ClockTime)
+modificationTimeIfExists f = do
+ (do t <- getModificationTime f; return (Just t))
+ `IO.catch` \e -> if isDoesNotExistError e
+ then return Nothing
+ else ioError e
+
+-- --------------------------------------------------------------
+-- Filename manipulation
+
+-- Filenames are kept "normalised" inside GHC, using '/' as the path
+-- separator. On Windows these functions will also recognise '\\' as
+-- the path separator, but will generally construct paths using '/'.
+
+type Suffix = String
+
+splitFilename :: String -> (String,Suffix)
+splitFilename f = splitLongestPrefix f (=='.')
+
+basenameOf :: FilePath -> String
+basenameOf = fst . splitFilename
+
+suffixOf :: FilePath -> Suffix
+suffixOf = snd . splitFilename
+
+joinFileExt :: String -> String -> FilePath
+joinFileExt path "" = path
+joinFileExt path ext = path ++ '.':ext
+
+-- "foo/bar/xyzzy.ext" -> ("foo/bar", "xyzzy.ext")
+splitFilenameDir :: String -> (String,String)
+splitFilenameDir str
+ = let (dir, rest) = splitLongestPrefix str isPathSeparator
+ (dir', rest') | null rest = (".", dir)
+ | otherwise = (dir, rest)
+ in (dir', rest')
+
+-- "foo/bar/xyzzy.ext" -> ("foo/bar", "xyzzy", ".ext")
+splitFilename3 :: String -> (String,String,Suffix)
+splitFilename3 str
+ = let (dir, rest) = splitFilenameDir str
+ (name, ext) = splitFilename rest
+ in (dir, name, ext)
+
+joinFileName :: String -> String -> FilePath
+joinFileName "" fname = fname
+joinFileName "." fname = fname
+joinFileName dir "" = dir
+joinFileName dir fname = dir ++ '/':fname
+
+-- split a string at the last character where 'pred' is True,
+-- returning a pair of strings. The first component holds the string
+-- up (but not including) the last character for which 'pred' returned
+-- True, the second whatever comes after (but also not including the
+-- last character).
+--
+-- If 'pred' returns False for all characters in the string, the original
+-- string is returned in the first component (and the second one is just
+-- empty).
+splitLongestPrefix :: String -> (Char -> Bool) -> (String,String)
+splitLongestPrefix str pred
+ | null r_pre = (str, [])
+ | otherwise = (reverse (tail r_pre), reverse r_suf)
+ -- 'tail' drops the char satisfying 'pred'
+ where
+ (r_suf, r_pre) = break pred (reverse str)
+
+replaceFilenameSuffix :: FilePath -> Suffix -> FilePath
+replaceFilenameSuffix file suf = basenameOf file `joinFileExt` suf
+
+-- directoryOf strips the filename off the input string, returning
+-- the directory.
+directoryOf :: FilePath -> String
+directoryOf = fst . splitFilenameDir
+
+-- filenameOf strips the directory off the input string, returning
+-- the filename.
+filenameOf :: FilePath -> String
+filenameOf = snd . splitFilenameDir
+
+replaceFilenameDirectory :: FilePath -> String -> FilePath
+replaceFilenameDirectory path dir = dir `joinFileName` filenameOf path
+
+escapeSpaces :: String -> String
+escapeSpaces = foldr (\c s -> if isSpace c then '\\':c:s else c:s) ""
+
+isPathSeparator :: Char -> Bool
+isPathSeparator ch =
+#ifdef mingw32_TARGET_OS
+ ch == '/' || ch == '\\'
+#else
+ ch == '/'
+#endif
+
+--------------------------------------------------------------
+-- * Search path
+--------------------------------------------------------------
+
+-- | The function splits the given string to substrings
+-- using the 'searchPathSeparator'.
+parseSearchPath :: String -> [FilePath]
+parseSearchPath path = split path
+ where
+ split :: String -> [String]
+ split s =
+ case rest' of
+ [] -> [chunk]
+ _:rest -> chunk : split rest
+ where
+ chunk =
+ case chunk' of
+#ifdef mingw32_HOST_OS
+ ('\"':xs@(_:_)) | last xs == '\"' -> init xs
+#endif
+ _ -> chunk'
+
+ (chunk', rest') = break (==searchPathSeparator) s
+
+-- | A platform-specific character used to separate search path strings in
+-- environment variables. The separator is a colon (\":\") on Unix and Macintosh,
+-- and a semicolon (\";\") on the Windows operating system.
+searchPathSeparator :: Char
+#if mingw32_HOST_OS || mingw32_TARGET_OS
+searchPathSeparator = ';'
+#else
+searchPathSeparator = ':'
+#endif
+
+-----------------------------------------------------------------------------
+-- Convert filepath into platform / MSDOS form.
+
+-- We maintain path names in Unix form ('/'-separated) right until
+-- the last moment. On Windows we dos-ify them just before passing them
+-- to the Windows command.
+--
+-- The alternative, of using '/' consistently on Unix and '\' on Windows,
+-- proved quite awkward. There were a lot more calls to platformPath,
+-- and even on Windows we might invoke a unix-like utility (eg 'sh'), which
+-- interpreted a command line 'foo\baz' as 'foobaz'.
+
+normalisePath :: String -> String
+-- Just changes '\' to '/'
+
+pgmPath :: String -- Directory string in Unix format
+ -> String -- Program name with no directory separators
+ -- (e.g. copy /y)
+ -> String -- Program invocation string in native format
+
+#if defined(mingw32_HOST_OS)
+--------------------- Windows version ------------------
+normalisePath xs = subst '\\' '/' xs
+pgmPath dir pgm = platformPath dir ++ '\\' : pgm
+platformPath p = subst '/' '\\' p
+
+subst a b ls = map (\ x -> if x == a then b else x) ls
+#else
+--------------------- Non-Windows version --------------
+normalisePath xs = xs
+pgmPath dir pgm = dir ++ '/' : pgm
+platformPath stuff = stuff
+--------------------------------------------------------
+#endif
\end{code}
projects / ghc-hetmet.git / blobdiff