X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Futils%2FUtil.lhs;h=ed7ee9aca6a27aadcc5d4c32a241b65d3e795506;hb=423d477bfecd490de1449c59325c8776f91d7aac;hp=734a321fd5a6f81cf530188bf35f739ed60e5d13;hpb=38efc48c81156a23665f7807a89b8b8a1ba9671e;p=ghc-hetmet.git diff --git a/ghc/compiler/utils/Util.lhs b/ghc/compiler/utils/Util.lhs index 734a321..ed7ee9a 100644 --- a/ghc/compiler/utils/Util.lhs +++ b/ghc/compiler/utils/Util.lhs @@ -1,105 +1,78 @@ % -% (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_ Ordering -# define LT_ LT -# define EQ_ EQ -# define GT_ GT -# define _LT LT -# define _EQ EQ -# define _GT GT -# define GT__ _ -# define tagCmp_ compare -# define _tagCmp compare -# 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 - -- The Eager monad - SYN_IE(Eager), thenEager, returnEager, mapEager, appEager, runEager, -- general list processing - IF_NOT_GHC(forall COMMA exists COMMA) zipEqual, zipWithEqual, zipWith3Equal, zipWith4Equal, - zipLazy, + zipLazy, stretchZipWith, mapAndUnzip, mapAndUnzip3, - nOfThem, lengthExceeds, isSingleton, -#if defined(COMPILING_GHC) - startsWith, endsWith, - isIn, isn'tIn, -#endif + nOfThem, filterOut, + lengthExceeds, lengthIs, lengthAtLeast, listLengthCmp, atLength, + isSingleton, only, + notNull, snocView, - -- association lists - assoc, assocUsing, assocDefault, assocDefaultUsing, + 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) + sortLt, naturalMergeSortLe, -- transitive closures transitiveClosure, -- accumulating - mapAccumL, mapAccumR, mapAccumB, + mapAccumL, mapAccumR, mapAccumB, + foldl2, count, + + takeList, dropList, splitAtList, -- comparisons -#if defined(COMPILING_GHC) - Ord3(..), thenCmp, cmpList, - cmpPString, FAST_STRING, -#else - cmpString, -#endif + eqListBy, equalLength, compareLength, + thenCmp, cmpList, prefixMatch, suffixMatch, maybePrefixMatch, + + -- strictness + foldl', seqList, -- pairs - IF_NOT_GHC(cfst COMMA applyToPair COMMA applyToFst COMMA) - IF_NOT_GHC(applyToSnd COMMA foldPair COMMA) - unzipWith + unzipWith, + + global, - -- error handling -#if defined(COMPILING_GHC) - , panic, panic#, pprPanic, pprPanic#, pprError, pprTrace - , assertPanic -#endif {- COMPILING_GHC -} + -- module names + looksLikeModuleName, + + toArgs, + -- Floating point stuff + readRational, ) where -#if defined(COMPILING_GHC) +#include "../includes/ghcconfig.h" +#include "HsVersions.h" -CHK_Ubiq() -- debugging consistency check -IMPORT_1_3(List(zipWith4)) +import Panic ( panic, trace ) +import FastTypes -#else -import List(zipWith4) +#if __GLASGOW_HASKELL__ <= 408 +import EXCEPTION ( catchIO, justIoErrors, raiseInThread ) #endif +import DATA_IOREF ( IORef, newIORef ) +import UNSAFE_IO ( unsafePerformIO ) + +import qualified List ( elem, notElem ) + +#ifndef DEBUG +import List ( zipWith4 ) +#endif + +import Char ( isUpper, isAlphaNum, isSpace, ord, isDigit ) +import Ratio ( (%) ) infixr 9 `thenCmp` \end{code} @@ -115,6 +88,8 @@ 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} +#if NOT_USED + type Eager ans a = (a -> ans) -> ans runEager :: Eager a a -> a @@ -134,22 +109,21 @@ mapEager f [] = returnEager [] mapEager f (x:xs) = f x `thenEager` \ y -> mapEager f xs `thenEager` \ ys -> returnEager (y:ys) +#endif \end{code} %************************************************************************ %* * -\subsection[Utils-version-support]{Functions to help pre-1.2 versions of (non-Glasgow) Haskell} +\subsection{A for loop} %* * %************************************************************************ -This is our own idea: \begin{code} -#ifndef __GLASGOW_HASKELL__ -data TAG_ = LT_ | EQ_ | GT_ - -tagCmp_ :: Ord a => a -> a -> TAG_ -tagCmp_ a b = if a == b then EQ_ else if a < b then LT_ else GT_ -#endif +-- 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} %************************************************************************ @@ -158,16 +132,12 @@ tagCmp_ a b = if a == b then EQ_ else if a < b then LT_ else GT_ %* * %************************************************************************ -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 - -exists :: (a -> Bool) -> [a] -> Bool -exists pred [] = False -exists pred (x:xs) = pred x || exists pred xs +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 @@ -214,6 +184,21 @@ zipLazy [] ys = [] 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} mapAndUnzip :: (a -> (b, c)) -> [a] -> ([b], [c]) @@ -238,34 +223,79 @@ mapAndUnzip3 f (x:xs) \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 -startsWith, endsWith :: String -> String -> Maybe String + atLen [] = EQ + atLen _ = GT -startsWith [] str = Just str -startsWith (c:cs) (s:ss) - = if c /= s then Nothing else startsWith cs ss -startsWith _ [] = Nothing +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 @@ -279,123 +309,25 @@ elem__ x (y:ys) = x==y || elem__ x ys 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 -assocDefault :: (Eq a) => b -> [(a, b)] -> a -> b -assocUsing :: (a -> a -> Bool) -> String -> [(a, b)] -> a -> b -assocDefaultUsing :: (a -> a -> Bool) -> b -> [(a, b)] -> a -> b - -assocDefaultUsing eq deflt ((k,v) : rest) key - | k `eq` key = v - | otherwise = assocDefaultUsing eq deflt rest key - -assocDefaultUsing eq deflt [] key = deflt - -assoc crash_msg list key = assocDefaultUsing (==) (panic ("Failed in assoc: " ++ crash_msg)) list key -assocDefault deflt list key = assocDefaultUsing (==) deflt list key -assocUsing eq crash_msg list key = assocDefaultUsing eq (panic ("Failed in assoc: " ++ crash_msg)) list 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) + | 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} %************************************************************************ @@ -411,6 +343,8 @@ removeDups cmp xs %************************************************************************ \begin{code} +#if NOT_USED + -- tail-recursive, etc., "quicker sort" [as per Meira thesis] quicksort :: (a -> a -> Bool) -- Less-than predicate -> [a] -- Input list @@ -423,14 +357,13 @@ quicksort lt (x:xs) = split x [] [] xs 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 +#endif \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 @@ -489,12 +422,13 @@ rqpart lt x (y:ys) rle rgt r = %************************************************************************ \begin{code} -mergesort :: (a -> a -> TAG_) -> [a] -> [a] +#if NOT_USED +mergesort :: (a -> a -> Ordering) -> [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 } + 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] @@ -510,9 +444,10 @@ mergesort cmp xs = merge_lists (split_into_runs [] xs) 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) + EQ -> x : y : (merge xs ys) + LT -> x : (merge xs yl) + GT -> y : (merge xl ys) +#endif \end{code} %************************************************************************ @@ -604,18 +539,21 @@ balancedFold' :: (a -> a -> a) -> [a] -> [a] 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 +#endif + naturalMergeSortLe le = generalNaturalMergeSort le \end{code} @@ -707,76 +645,114 @@ mapAccumB f a b (x:xs) = (a'',b'',y:ys) (a'',b',ys) = mapAccumB f a' b xs \end{code} -%************************************************************************ -%* * -\subsection[Utils-comparison]{Comparisons} -%* * -%************************************************************************ +A strict version of foldl. -See also @tagCmp_@ near the versions-compatibility section. +\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} -The Ord3 class will be subsumed into Ord in Haskell 1.3. +A combination of foldl with zip. It works with equal length lists. \begin{code} -class Ord3 a where - cmp :: a -> a -> TAG_ +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 +\end{code} -thenCmp :: TAG_ -> TAG_ -> TAG_ -{-# INLINE thenCmp #-} -thenCmp EQ_ any = any -thenCmp other any = other +Count the number of times a predicate is true -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 } +\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} -\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) +@splitAt@, @take@, and @drop@ but with length of another +list giving the break-off point: -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 +\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 -instance Ord3 Int where - cmp a b | a < b = LT_ - | a > b = GT_ - | otherwise = EQ_ \end{code} + +%************************************************************************ +%* * +\subsection[Utils-comparison]{Comparisons} +%* * +%************************************************************************ + \begin{code} -cmpString :: String -> String -> TAG_ +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 +thenCmp other any = other -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 -#ifdef COMPILING_GHC -cmpString _ _ = panic# "cmpString" -#else -cmpString _ _ = error "cmpString" -#endif +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 (tagCmpFS 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) \end{code} %************************************************************************ @@ -788,14 +764,17 @@ cmpPString x y 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) @@ -804,11 +783,7 @@ applyToFst f (x,y) = (f x,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} @@ -816,40 +791,100 @@ unzipWith :: (a -> b -> c) -> [(a, b)] -> [c] 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.gla.ac.uk.\n\n" ) +global :: a -> IORef a +global a = unsafePerformIO (newIORef a) +\end{code} -pprPanic heading pretty_msg = panic (heading++(show pretty_msg)) -pprError heading pretty_msg = error (heading++(show pretty_msg)) -#if __GLASGOW_HASKELL__ == 201 -pprTrace heading pretty_msg = GHCbase.trace (heading++(show pretty_msg)) -#elif __GLASGOW_HASKELL__ >= 202 -pprTrace heading pretty_msg = GlaExts.trace (heading++(show pretty_msg)) -#else -pprTrace heading pretty_msg = trace (heading++(show pretty_msg)) -#endif +Module names: --- #-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) +\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} -panic# :: String -> TAG_ -panic# s = case (panic s) of () -> EQ_ +Akin to @Prelude.words@, but sensitive to dquoted entities treating +them as single words. -pprPanic# heading pretty_msg = panic# (heading++(show pretty_msg)) +\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} -assertPanic :: String -> Int -> a -assertPanic file line = panic ("ASSERT failed! file "++file++", line "++show line) +-- ----------------------------------------------------------------------------- +-- Floats -#endif {- COMPILING_GHC -} +\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) \end{code}