@@ -3,6 +3,9 @@
33#if __GLASGOW_HASKELL__ >= 702
44{-# LANGUAGE Trustworthy #-}
55#endif
6+#if __GLASGOW_HASKELL__ >= 708
7+{-# LANGUAGE TypeFamilies #-}
8+#endif
69
710-- |
811-- Module : Data.Text
@@ -11,8 +14,7 @@
1114-- (c) 2008, 2009 Tom Harper
1215--
1316-- License : BSD-style
14−-- Maintainer : bos@serpentine.com, rtomharper@googlemail.com,
15−-- duncan@haskell.org
17+-- Maintainer : bos@serpentine.com
1618-- Stability : experimental
1719-- Portability : GHC
1820--
@@ -30,8 +32,8 @@
3032--
3133-- To use an extended and very rich family of functions for working
3234-- with Unicode text (including normalization, regular expressions,
33−-- non-standard encodings, text breaking, and locales), see the
34−-- @text-icu@ package: <http://hackage.haskell.org/package/text-icu>
35+-- non-standard encodings, text breaking, and locales), see
36+-- <http://hackage.haskell.org/package/text-icu the text-icu package >.
3537
3638module Data.Text
3739 (
@@ -123,8 +125,11 @@ module Data.Text
123125
124126 -- ** Breaking strings
125127 , take
128+ , takeEnd
126129 , drop
130+ , dropEnd
127131 , takeWhile
132+ , takeWhileEnd
128133 , dropWhile
129134 , dropWhileEnd
130135 , dropAround
@@ -187,82 +192,94 @@ module Data.Text
187192
188193 -- * Low level operations
189194 , copy
195+ , unpackCString#
190196 ) where
191197
192198import Prelude (Char, Bool(..), Int, Maybe(..), String,
193199 Eq(..), Ord(..), Ordering(..), (++),
194− Read(..), Show(..),
195− (&&), (||), (+), (-), (.), ($), ($!), (>>), (*),
196− maxBound, not, return, otherwise, quot)
200+ Read(..),
201+ (&&), (||), (+), (-), (.), ($), ($!), (>>),
202+ not, return, otherwise, quot)
197203#if defined(HAVE_DEEPSEQ)
198−import Control.DeepSeq (NFData)
204+import Control.DeepSeq (NFData(rnf))
199205#endif
200206#if defined(ASSERTS)
201207import Control.Exception (assert)
202208#endif
203209import Data.Char (isSpace)
204−import Data.Data (Data(gfoldl, toConstr, gunfold, dataTypeOf))
205−import Data.Data (mkNoRepType)
210+import Data.Data (Data(gfoldl, toConstr, gunfold, dataTypeOf), constrIndex,
211+ Constr, mkConstr, DataType, mkDataType, Fixity(Prefix))
206212import Control.Monad (foldM)
213+import Control.Monad.ST (ST)
207214import qualified Data.Text.Array as A
208215import qualified Data.List as L
216+import Data.Binary (Binary(get, put))
209217import Data.Monoid (Monoid(..))
218+#if MIN_VERSION_base(4,9,0)
219+import Data.Semigroup (Semigroup(..))
220+#endif
210221import Data.String (IsString(..))
211−import qualified Data.Text.Fusion as S
212−import qualified Data.Text.Fusion.Common as S
213−import Data.Text.Fusion (stream, reverseStream, unstream)
214−import Data.Text.Private (span_)
215−import Data.Text.Internal (Text(..), empty, firstf, safe, text, textP)
222+import qualified Data.Text.Internal.Fusion as S
223+import qualified Data.Text.Internal.Fusion.Common as S
224+import Data.Text.Encoding (decodeUtf8', encodeUtf8)
225+import Data.Text.Internal.Fusion (stream, reverseStream, unstream)
226+import Data.Text.Internal.Private (span_)
227+import Data.Text.Internal (Text(..), empty, firstf, mul, safe, text)
228+import Data.Text.Show (singleton, unpack, unpackCString#)
216229import qualified Prelude as P
217230import Data.Text.Unsafe (Iter(..), iter, iter_, lengthWord16, reverseIter,
218− unsafeHead, unsafeTail)
219−import Data.Text.UnsafeChar (unsafeChr)
220−import qualified Data.Text.Util as U
221−import qualified Data.Text.Encoding.Utf16 as U16
222−import Data.Text.Search (indices)
231+ reverseIter_, unsafeHead, unsafeTail)
232+import Data.Text.Internal.Unsafe.Char (unsafeChr)
233+import qualified Data.Text.Internal.Functions as F
234+import qualified Data.Text.Internal.Encoding.Utf16 as U16
235+import Data.Text.Internal.Search (indices)
223236#if defined(__HADDOCK__)
224237import Data.ByteString (ByteString)
225238import qualified Data.Text.Lazy as L
226239import Data.Int (Int64)
227240#endif
228−#if __GLASGOW_HASKELL__ >= 702
229−import qualified GHC.CString as GHC
230−#else
231−import qualified GHC.Base as GHC
241+import GHC.Base (eqInt, neInt, gtInt, geInt, ltInt, leInt)
242+#if __GLASGOW_HASKELL__ >= 708
243+import qualified GHC.Exts as Exts
244+#endif
245+#if MIN_VERSION_base(4,7,0)
246+import Text.Printf (PrintfArg, formatArg, formatString)
232247#endif
233−import GHC.Prim (Addr#)
234248
235249-- $strict
236250--
237251-- This package provides both strict and lazy 'Text' types. The
238−-- strict type is provided by the 'Data.Text' package, while the lazy
239−-- type is provided by the 'Data.Text.Lazy' package. Internally, the
252+-- strict type is provided by the "Data.Text" module, while the lazy
253+-- type is provided by the "Data.Text.Lazy" module. Internally, the
240254-- lazy @Text@ type consists of a list of strict chunks.
241255--
242256-- The strict 'Text' type requires that an entire string fit into
243−-- memory at once. The lazy @Text@ type is capable of streaming
244−-- strings that are larger than memory using a small memory footprint.
245−-- In many cases, the overhead of chunked streaming makes the lazy
246−-- @Text@ type slower than its strict counterpart, but this is not
247−-- always the case. Sometimes, the time complexity of a function in
248−-- one module may be different from the other, due to their differing
249−-- internal structures.
257+-- memory at once. The lazy 'Data.Text.Lazy.Text' type is capable of
258+-- streaming strings that are larger than memory using a small memory
259+-- footprint. In many cases, the overhead of chunked streaming makes
260+-- the lazy 'Data.Text.Lazy.Text' type slower than its strict
261+-- counterpart, but this is not always the case. Sometimes, the time
262+-- complexity of a function in one module may be different from the
263+-- other, due to their differing internal structures.
250264--
251265-- Each module provides an almost identical API, with the main
252266-- difference being that the strict module uses 'Int' values for
253−-- lengths and counts, while the lazy module uses 'Int64' lengths.
267+-- lengths and counts, while the lazy module uses 'Data.Int.Int64'
268+-- lengths.
254269
255270-- $replacement
256271--
257272-- A 'Text' value is a sequence of Unicode scalar values, as defined
258−-- in §3.9, definition D76 of the Unicode 5.2 standard:
259−-- <http://www.unicode.org/versions/Unicode5.2.0/ch03.pdf#page=35>. As
260−-- such, a 'Text' cannot contain values in the range U+D800 to U+DFFF
261−-- inclusive. Haskell implementations admit all Unicode code points
262−-- (§3.4, definition D10) as 'Char' values, including code points
263−-- from this invalid range. This means that there are some 'Char'
264−-- values that are not valid Unicode scalar values, and the functions
265−-- in this module must handle those cases.
273+-- in
274+-- <http://www.unicode.org/versions/Unicode5.2.0/ch03.pdf#page=35 §3.9, definition D76 of the Unicode 5.2 standard >.
275+-- As such, a 'Text' cannot contain values in the range U+D800 to
276+-- U+DFFF inclusive. Haskell implementations admit all Unicode code
277+-- points
278+-- (<http://www.unicode.org/versions/Unicode5.2.0/ch03.pdf#page=13 §3.4, definition D10 >)
279+-- as 'Char' values, including code points from this invalid range.
280+-- This means that there are some 'Char' values that are not valid
281+-- Unicode scalar values, and the functions in this module must handle
282+-- those cases.
266283--
267284-- Within this module, many functions construct a 'Text' from one or
268285-- more 'Char' values. Those functions will substitute 'Char' values
@@ -276,8 +293,8 @@ import GHC.Prim (Addr#)
276293-- range U+D800 through U+DFFF are used by UTF-16 to denote surrogate
277294-- code points, and so cannot be represented. The functions replace
278295-- invalid scalar values, instead of dropping them, as a security
279−-- measure. For details, see Unicode Technical Report 36, §3.5:
280−-- <http://unicode.org/reports/tr36/#Deletion_of_Noncharacters>)
296+-- measure. For details, see
297+-- <http://unicode.org/reports/tr36/#Deletion_of_Noncharacters Unicode Technical Report 36, §3.5 >.)
281298
282299-- $fusion
283300--
@@ -295,11 +312,11 @@ import GHC.Prim (Addr#)
295312-- > countChars = T.length . T.toUpper . E.decodeUtf8
296313--
297314-- From the type signatures involved, this looks like it should
298−-- allocate one 'ByteString' value, and two 'Text' values. However,
299−-- when a module is compiled with optimisation enabled under GHC, the
300−-- two intermediate 'Text' values will be optimised away, and the
301−-- function will be compiled down to a single loop over the source
302−-- 'ByteString'.
315+-- allocate one 'Data.ByteString.ByteString' value, and two 'Text'
316+-- values. However, when a module is compiled with optimisation
317+-- enabled under GHC, the two intermediate 'Text' values will be
318+-- optimised away, and the function will be compiled down to a single
319+-- loop over the source 'Data.ByteString.ByteString'.
303320--
304321-- Functions that can be fused by the compiler are documented with the
305322-- phrase \"Subject to fusion\".
@@ -313,41 +330,82 @@ instance Eq Text where
313330instance Ord Text where
314331 compare = compareText
315332
316−instance Show Text where
317− showsPrec p ps r = showsPrec p (unpack ps) r
318−
319333instance Read Text where
320334 readsPrec p str = [(pack x,y) | (x,y) <- readsPrec p str]
321335
336+#if MIN_VERSION_base(4,9,0)
337+-- Semigroup orphan instances for older GHCs are provided by
338+-- 'semigroups` package
339+
340+instance Semigroup Text where
341+ (<>) = append
342+#endif
343+
322344instance Monoid Text where
323345 mempty = empty
346+#if MIN_VERSION_base(4,9,0)
347+ mappend = (<>) -- future-proof definition
348+#else
324349 mappend = append
350+#endif
325351 mconcat = concat
326352
327353instance IsString Text where
328354 fromString = pack
329355
356+#if __GLASGOW_HASKELL__ >= 708
357+instance Exts.IsList Text where
358+ type Item Text = Char
359+ fromList = pack
360+ toList = unpack
361+#endif
362+
330363#if defined(HAVE_DEEPSEQ)
331−instance NFData Text
364+instance NFData Text where rnf !_ = ()
332365#endif
333366
334−-- This instance preserves data abstraction at the cost of inefficiency.
367+instance Binary Text where
368+ put t = put (encodeUtf8 t)
369+ get = do
370+ bs <- get
371+ case decodeUtf8' bs of
372+ P.Left exn -> P.fail (P.show exn)
373+ P.Right a -> P.return a
374+
375+-- | This instance preserves data abstraction at the cost of inefficiency.
335376-- We omit reflection services for the sake of data abstraction.
336377--
337−-- This instance was created by copying the behavior of Data.Set and
338−-- Data.Map. If you feel a mistake has been made, please feel free to
339−-- submit improvements.
378+-- This instance was created by copying the updated behavior of
379+-- @"Data.Set".@'Data.Set.Set' and @"Data.Map".@'Data.Map.Map'. If you
380+-- feel a mistake has been made, please feel free to submit
381+-- improvements.
340382--
341−-- Original discussion is archived here:
342−
343−-- "could we get a Data instance for Data.Text.Text?"
344−-- http://groups.google.com/group/haskell-cafe/browse_thread/thread/b5bbb1b28a7e525d/0639d46852575b93
383+-- The original discussion is archived here:
384+-- <http://groups.google.com/group/haskell-cafe/browse_thread/thread/b5bbb1b28a7e525d/0639d46852575b93 could we get a Data instance for Data.Text.Text? >
385+--
386+-- The followup discussion that changed the behavior of 'Data.Set.Set'
387+-- and 'Data.Map.Map' is archived here:
388+-- <http://markmail.org/message/trovdc6zkphyi3cr#query:+page:1+mid:a46der3iacwjcf6n+state:results Proposal: Allow gunfold for Data.Map, ... >
345389
346390instance Data Text where
347391 gfoldl f z txt = z pack `f` (unpack txt)
348− toConstr _ = P.error "Data.Text.Text.toConstr"
349− gunfold _ _ = P.error "Data.Text.Text.gunfold"
350− dataTypeOf _ = mkNoRepType "Data.Text.Text"
392+ toConstr _ = packConstr
393+ gunfold k z c = case constrIndex c of
394+ 1 -> k (z pack)
395+ _ -> P.error "gunfold"
396+ dataTypeOf _ = textDataType
397+
398+#if MIN_VERSION_base(4,7,0)
399+-- | Only defined for @base-4.7.0.0@ and later
400+instance PrintfArg Text where
401+ formatArg txt = formatString $ unpack txt
402+#endif
403+
404+packConstr :: Constr
405+packConstr = mkConstr textDataType "pack" [] Prefix
406+
407+textDataType :: DataType
408+textDataType = mkDataType "Data.Text.Text" [packConstr]
351409
352410-- | /O(n)/ Compare two 'Text' values lexicographically.
353411compareText :: Text -> Text -> Ordering
@@ -372,30 +430,6 @@ pack :: String -> Text
372430pack = unstream . S.map safe . S.streamList
373431{-# INLINE [1] pack #-}
374432
375−-- | /O(n)/ Convert a Text into a String. Subject to fusion.
376−unpack :: Text -> String
377−unpack = S.unstreamList . stream
378−{-# INLINE [1] unpack #-}
379−
380−-- | /O(n)/ Convert a literal string into a Text. Subject to fusion.
381−unpackCString# :: Addr# -> Text
382−unpackCString# addr# = unstream (S.streamCString# addr#)
383−{-# NOINLINE unpackCString# #-}
384−
385−{-# RULES "TEXT literal" forall a.
386− unstream (S.map safe (S.streamList (GHC.unpackCString# a)))
387− = unpackCString# a #-}
388−
389−{-# RULES "TEXT literal UTF8" forall a.
390− unstream (S.map safe (S.streamList (GHC.unpackCStringUtf8# a)))
391− = unpackCString# a #-}
392−
393−-- | /O(1)/ Convert a character into a Text. Subject to fusion.
394−-- Performs replacement on invalid scalar values.
395−singleton :: Char -> Text
396−singleton = unstream . S.singleton . safe
397−{-# INLINE [1] singleton #-}
398−
399433-- -----------------------------------------------------------------------------
400434-- * Basic functions
401435
@@ -426,12 +460,13 @@ append a@(Text arr1 off1 len1) b@(Text arr2 off2 len2)
426460 | otherwise = overflowError "append"
427461 where
428462 len = len1+len2
463+ x :: ST s (A.MArray s)
429464 x = do
430465 arr <- A.new len
431466 A.copyI arr 0 arr1 off1 len1
432467 A.copyI arr len1 arr2 off2 len
433468 return arr
434−{-# INLINE append #-}
469+{-# NOINLINE append #-}
435470
436471{-# RULES
437472"TEXT append -> fused" [~1] forall t1 t2.
@@ -451,8 +486,8 @@ head t = S.head (stream t)
451486uncons :: Text -> Maybe (Char, Text)
452487uncons t@(Text arr off len)
453488 | len <= 0 = Nothing
454− | otherwise = Just (c, textP arr (off+d) (len-d))
455− where Iter c d = iter t 0
489+ | otherwise = Just $ let !(Iter c d) = iter t 0
490+ in (c, text arr (off+d) (len-d))
456491{-# INLINE [1] uncons #-}
457492
458493-- | Lifted from Control.Arrow and specialized.
@@ -482,7 +517,7 @@ last (Text arr off len)
482517tail :: Text -> Text
483518tail t@(Text arr off len)
484519 | len <= 0 = emptyError "tail"
485− | otherwise = textP arr (off+d) (len-d)
520+ | otherwise = text arr (off+d) (len-d)
486521 where d = iter_ t 0
487522{-# INLINE [1] tail #-}
488523
@@ -497,8 +532,8 @@ tail t@(Text arr off len)
497532-- be non-empty. Subject to fusion.
498533init :: Text -> Text
499534init (Text arr off len) | len <= 0 = emptyError "init"
500− | n >= 0xDC00 && n <= 0xDFFF = textP arr off (len-2)
501− | otherwise = textP arr off (len-1)
535+ | n >= 0xDC00 && n <= 0xDFFF = text arr off (len-2)
536+ | otherwise = text arr off (len-1)
502537 where
503538 n = A.unsafeIndex arr (off+len-1)
504539{-# INLINE [1] init #-}
@@ -537,7 +572,9 @@ isSingleton = S.isSingleton . stream
537572-- Subject to fusion.
538573length :: Text -> Int
539574length t = S.length (stream t)
540−{-# INLINE length #-}
575+{-# INLINE [0] length #-}
576+-- length needs to be phased after the compareN/length rules otherwise
577+-- it may inline before the rules have an opportunity to fire.
541578
542579-- | /O(n)/ Compare the count of characters in a 'Text' to a number.
543580-- Subject to fusion.
@@ -556,32 +593,32 @@ compareLength t n = S.compareLengthI (stream t) n
556593
557594{-# RULES
558595"TEXT ==N/length -> compareLength/==EQ" [~1] forall t n.
559− (==) (length t) n = compareLength t n == EQ
596+ eqInt (length t) n = compareLength t n == EQ
560597 #-}
561598
562599{-# RULES
563600"TEXT /=N/length -> compareLength//=EQ" [~1] forall t n.
564− (/=) (length t) n = compareLength t n /= EQ
601+ neInt (length t) n = compareLength t n /= EQ
565602 #-}
566603
567604{-# RULES
568605"TEXT <N/length -> compareLength/==LT" [~1] forall t n.
569− (<) (length t) n = compareLength t n == LT
606+ ltInt (length t) n = compareLength t n == LT
570607 #-}
571608
572609{-# RULES
573610"TEXT <=N/length -> compareLength//=GT" [~1] forall t n.
574− (<=) (length t) n = compareLength t n /= GT
611+ leInt (length t) n = compareLength t n /= GT
575612 #-}
576613
577614{-# RULES
578615"TEXT >N/length -> compareLength/==GT" [~1] forall t n.
579− (>) (length t) n = compareLength t n == GT
616+ gtInt (length t) n = compareLength t n == GT
580617 #-}
581618
582619{-# RULES
583620"TEXT >=N/length -> compareLength//=LT" [~1] forall t n.
584− (>=) (length t) n = compareLength t n /= LT
621+ geInt (length t) n = compareLength t n /= LT
585622 #-}
586623
587624-- -----------------------------------------------------------------------------
@@ -597,7 +634,7 @@ map f t = unstream (S.map (safe . f) (stream t))
597634-- 'Text's and concatenates the list after interspersing the first
598635-- argument between each element of the list.
599636intercalate :: Text -> [Text] -> Text
600−intercalate t = concat . (U.intersperse t)
637+intercalate t = concat . (F.intersperse t)
601638{-# INLINE intercalate #-}
602639
603640-- | /O(n)/ The 'intersperse' function takes a character and places it
@@ -612,22 +649,48 @@ reverse :: Text -> Text
612649reverse t = S.reverse (stream t)
613650{-# INLINE reverse #-}
614651
615−-- | /O(m+n)/ Replace every occurrence of one substring with another.
652+-- | /O(m+n)/ Replace every non-overlapping occurrence of @needle@ in
653+-- @haystack@ with @replacement@.
654+--
655+-- This function behaves as though it was defined as follows:
656+--
657+-- @
658+-- replace needle replacement haystack =
659+-- 'intercalate' replacement ('splitOn' needle haystack)
660+-- @
661+--
662+-- As this suggests, each occurrence is replaced exactly once. So if
663+-- @needle@ occurs in @replacement@, that occurrence will /not/ itself
664+-- be replaced recursively:
665+--
666+-- > replace "oo" "foo" "oo" == "foo"
667+--
668+-- In cases where several instances of @needle@ overlap, only the
669+-- first one will be replaced:
670+--
671+-- > replace "ofo" "bar" "ofofo" == "barfo"
616672--
617673-- In (unlikely) bad cases, this function's time complexity degrades
618674-- towards /O(n*m)/.
619−replace :: Text -> Text -> Text -> Text
675+replace :: Text
676+ -- ^ @needle@ to search for. If this string is empty, an
677+ -- error will occur.
678+ -> Text
679+ -- ^ @replacement@ to replace @needle@ with.
680+ -> Text
681+ -- ^ @haystack@ in which to search.
682+ -> Text
620683replace needle@(Text _ _ neeLen)
621684 (Text repArr repOff repLen)
622685 haystack@(Text hayArr hayOff hayLen)
623686 | neeLen == 0 = emptyError "replace"
624687 | L.null ixs = haystack
625688 | len > 0 = Text (A.run x) 0 len
626− | len < 0 = overflowError "replace"
627689 | otherwise = empty
628690 where
629691 ixs = indices needle haystack
630− len = hayLen - (neeLen - repLen) * L.length ixs
692+ len = hayLen - (neeLen - repLen) `mul` L.length ixs
693+ x :: ST s (A.MArray s)
631694 x = do
632695 marr <- A.new len
633696 let loop (i:is) o d = do
@@ -657,9 +720,8 @@ replace needle@(Text _ _ neeLen)
657720-- /Note/: In some languages, case conversion is a locale- and
658721-- context-dependent operation. The case conversion functions in this
659722-- module are /not/ locale sensitive. Programs that require locale
660−-- sensitivity should use appropriate versions of the case mapping
661−-- functions from the @text-icu@ package:
662−-- <http://hackage.haskell.org/package/text-icu>
723+-- sensitivity should use appropriate versions of the
724+-- <http://hackage.haskell.org/package/text-icu-0.6.3.7/docs/Data-Text-ICU.html#g:4 case mapping functions from the text-icu package >.
663725
664726-- | /O(n)/ Convert a string to folded case. Subject to fusion.
665727--
@@ -679,7 +741,7 @@ replace needle@(Text _ _ neeLen)
679741-- instead of itself.
680742toCaseFold :: Text -> Text
681743toCaseFold t = unstream (S.toCaseFold (stream t))
682−{-# INLINE [0] toCaseFold #-}
744+{-# INLINE toCaseFold #-}
683745
684746-- | /O(n)/ Convert a string to lower case, using simple case
685747-- conversion. Subject to fusion.
@@ -839,6 +901,7 @@ concat ts = case ts' of
839901 where
840902 ts' = L.filter (not . null) ts
841903 len = sumP "concat" $ L.map lengthWord16 ts'
904+ go :: ST s (A.MArray s)
842905 go = do
843906 arr <- A.new len
844907 let step i (Text a o l) =
@@ -852,13 +915,13 @@ concatMap f = concat . foldr ((:) . f) []
852915{-# INLINE concatMap #-}
853916
854917-- | /O(n)/ 'any' @p@ @t@ determines whether any character in the
855−-- 'Text' @t@ satisifes the predicate @p@. Subject to fusion.
918+-- 'Text' @t@ satisfies the predicate @p@. Subject to fusion.
856919any :: (Char -> Bool) -> Text -> Bool
857920any p t = S.any p (stream t)
858921{-# INLINE any #-}
859922
860923-- | /O(n)/ 'all' @p@ @t@ determines whether all characters in the
861−-- 'Text' @t@ satisify the predicate @p@. Subject to fusion.
924+-- 'Text' @t@ satisfy the predicate @p@. Subject to fusion.
862925all :: (Char -> Bool) -> Text -> Bool
863926all p t = S.all p (stream t)
864927{-# INLINE all #-}
@@ -949,10 +1012,10 @@ replicate n t@(Text a o l)
9491012 | n <= 0 || l <= 0 = empty
9501013 | n == 1 = t
9511014 | isSingleton t = replicateChar n (unsafeHead t)
952− | n <= maxBound `quot` l = Text (A.run x) 0 len
953− | otherwise = overflowError "replicate"
1015+ | otherwise = Text (A.run x) 0 len
9541016 where
955− len = l * n
1017+ len = l `mul` n
1018+ x :: ST s (A.MArray s)
9561019 x = do
9571020 arr <- A.new len
9581021 let loop !d !i | i >= n = return arr
@@ -1003,14 +1066,16 @@ take :: Int -> Text -> Text
10031066take n t@(Text arr off len)
10041067 | n <= 0 = empty
10051068 | n >= len = t
1006− | otherwise = Text arr off (loop 0 0)
1007− where
1008− loop !i !cnt
1009− | i >= len || cnt >= n = i
1010− | otherwise = loop (i+d) (cnt+1)
1011− where d = iter_ t i
1069+ | otherwise = text arr off (iterN n t)
10121070{-# INLINE [1] take #-}
10131071
1072+iterN :: Int -> Text -> Int
1073+iterN n t@(Text _arr _off len) = loop 0 0
1074+ where loop !i !cnt
1075+ | i >= len || cnt >= n = i
1076+ | otherwise = loop (i+d) (cnt+1)
1077+ where d = iter_ t i
1078+
10141079{-# RULES
10151080"TEXT take -> fused" [~1] forall n t.
10161081 take n t = unstream (S.take n (stream t))
@@ -1018,6 +1083,27 @@ take n t@(Text arr off len)
10181083 unstream (S.take n (stream t)) = take n t
10191084 #-}
10201085
1086+-- | /O(n)/ 'takeEnd' @n@ @t@ returns the suffix remaining after
1087+-- taking @n@ characters from the end of @t@.
1088+--
1089+-- Examples:
1090+--
1091+-- > takeEnd 3 "foobar" == "bar"
1092+takeEnd :: Int -> Text -> Text
1093+takeEnd n t@(Text arr off len)
1094+ | n <= 0 = empty
1095+ | n >= len = t
1096+ | otherwise = text arr (off+i) (len-i)
1097+ where i = iterNEnd n t
1098+
1099+iterNEnd :: Int -> Text -> Int
1100+iterNEnd n t@(Text _arr _off len) = loop (len-1) n
1101+ where loop i !m
1102+ | i <= 0 = 0
1103+ | m <= 1 = i
1104+ | otherwise = loop (i+d) (m-1)
1105+ where d = reverseIter_ t i
1106+
10211107-- | /O(n)/ 'drop' @n@, applied to a 'Text', returns the suffix of the
10221108-- 'Text' after the first @n@ characters, or the empty 'Text' if @n@
10231109-- is greater than the length of the 'Text'. Subject to fusion.
@@ -1025,11 +1111,8 @@ drop :: Int -> Text -> Text
10251111drop n t@(Text arr off len)
10261112 | n <= 0 = t
10271113 | n >= len = empty
1028− | otherwise = loop 0 0
1029− where loop !i !cnt
1030− | i >= len || cnt >= n = Text arr (off+i) (len-i)
1031− | otherwise = loop (i+d) (cnt+1)
1032− where d = iter_ t i
1114+ | otherwise = text arr (off+i) (len-i)
1115+ where i = iterN n t
10331116{-# INLINE [1] drop #-}
10341117
10351118{-# RULES
@@ -1039,6 +1122,18 @@ drop n t@(Text arr off len)
10391122 unstream (S.drop n (stream t)) = drop n t
10401123 #-}
10411124
1125+-- | /O(n)/ 'dropEnd' @n@ @t@ returns the prefix remaining after
1126+-- dropping @n@ characters from the end of @t@.
1127+--
1128+-- Examples:
1129+--
1130+-- > dropEnd 3 "foobar" == "foo"
1131+dropEnd :: Int -> Text -> Text
1132+dropEnd n t@(Text arr off len)
1133+ | n <= 0 = t
1134+ | n >= len = empty
1135+ | otherwise = text arr off (iterNEnd n t)
1136+
10421137-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text',
10431138-- returns the longest prefix (possibly empty) of elements that
10441139-- satisfy @p@. Subject to fusion.
@@ -1046,7 +1141,7 @@ takeWhile :: (Char -> Bool) -> Text -> Text
10461141takeWhile p t@(Text arr off len) = loop 0
10471142 where loop !i | i >= len = t
10481143 | p c = loop (i+d)
1049− | otherwise = textP arr off i
1144+ | otherwise = text arr off i
10501145 where Iter c d = iter t i
10511146{-# INLINE [1] takeWhile #-}
10521147
@@ -1057,6 +1152,27 @@ takeWhile p t@(Text arr off len) = loop 0
10571152 unstream (S.takeWhile p (stream t)) = takeWhile p t
10581153 #-}
10591154
1155+-- | /O(n)/ 'takeWhileEnd', applied to a predicate @p@ and a 'Text',
1156+-- returns the longest suffix (possibly empty) of elements that
1157+-- satisfy @p@. Subject to fusion.
1158+-- Examples:
1159+--
1160+-- > takeWhileEnd (=='o') "foo" == "oo"
1161+takeWhileEnd :: (Char -> Bool) -> Text -> Text
1162+takeWhileEnd p t@(Text arr off len) = loop (len-1) len
1163+ where loop !i !l | l <= 0 = t
1164+ | p c = loop (i+d) (l+d)
1165+ | otherwise = text arr (off+l) (len-l)
1166+ where (c,d) = reverseIter t i
1167+{-# INLINE [1] takeWhileEnd #-}
1168+
1169+{-# RULES
1170+"TEXT takeWhileEnd -> fused" [~1] forall p t.
1171+ takeWhileEnd p t = S.reverse (S.takeWhile p (S.reverseStream t))
1172+"TEXT takeWhileEnd -> unfused" [1] forall p t.
1173+ S.reverse (S.takeWhile p (S.reverseStream t)) = takeWhileEnd p t
1174+ #-}
1175+
10601176-- | /O(n)/ 'dropWhile' @p@ @t@ returns the suffix remaining after
10611177-- 'takeWhile' @p@ @t@. Subject to fusion.
10621178dropWhile :: (Char -> Bool) -> Text -> Text
@@ -1075,8 +1191,9 @@ dropWhile p t@(Text arr off len) = loop 0 0
10751191 #-}
10761192
10771193-- | /O(n)/ 'dropWhileEnd' @p@ @t@ returns the prefix remaining after
1078−-- dropping characters that fail the predicate @p@ from the end of
1194+-- dropping characters that satisfy the predicate @p@ from the end of
10791195-- @t@. Subject to fusion.
1196+--
10801197-- Examples:
10811198--
10821199-- > dropWhileEnd (=='.') "foo..." == "foo"
@@ -1096,7 +1213,7 @@ dropWhileEnd p t@(Text arr off len) = loop (len-1) len
10961213 #-}
10971214
10981215-- | /O(n)/ 'dropAround' @p@ @t@ returns the substring remaining after
1099−-- dropping characters that fail the predicate @p@ from both the
1216+-- dropping characters that satisfy the predicate @p@ from both the
11001217-- beginning and end of @t@. Subject to fusion.
11011218dropAround :: (Char -> Bool) -> Text -> Text
11021219dropAround p = dropWhile p . dropWhileEnd p
@@ -1131,13 +1248,8 @@ splitAt :: Int -> Text -> (Text, Text)
11311248splitAt n t@(Text arr off len)
11321249 | n <= 0 = (empty, t)
11331250 | n >= len = (t, empty)
1134− | otherwise = (Text arr off k, Text arr (off+k) (len-k))
1135− where k = loop 0 0
1136− loop !i !cnt
1137− | i >= len || cnt >= n = i
1138− | otherwise = loop (i+d) (cnt+1)
1139− where d = iter_ t i
1140−{-# INLINE splitAt #-}
1251+ | otherwise = let k = iterN n t
1252+ in (text arr off k, text arr (off+k) (len-k))
11411253
11421254-- | /O(n)/ 'span', applied to a predicate @p@ and text @t@, returns
11431255-- a pair whose first element is the longest prefix (possibly empty)
@@ -1196,9 +1308,9 @@ tails t | null t = [empty]
11961308-- copies to create substrings; they just construct new 'Text's that
11971309-- are slices of the original.
11981310
1199−-- | /O(m+n)/ Break a 'Text' into pieces separated by the first
1200−-- 'Text' argument, consuming the delimiter. An empty delimiter is
1201−-- invalid, and will cause an error to be raised.
1311+-- | /O(m+n)/ Break a 'Text' into pieces separated by the first 'Text'
1312+-- argument (which cannot be empty), consuming the delimiter. An empty
1313+-- delimiter is invalid, and will cause an error to be raised.
12021314--
12031315-- Examples:
12041316--
@@ -1211,16 +1323,23 @@ tails t | null t = [empty]
12111323-- > intercalate s . splitOn s == id
12121324-- > splitOn (singleton c) == split (==c)
12131325--
1326+-- (Note: the string @s@ to split on above cannot be empty.)
1327+--
12141328-- In (unlikely) bad cases, this function's time complexity degrades
12151329-- towards /O(n*m)/.
1216−splitOn :: Text -> Text -> [Text]
1330+splitOn :: Text
1331+ -- ^ String to split on. If this string is empty, an error
1332+ -- will occur.
1333+ -> Text
1334+ -- ^ Input text.
1335+ -> [Text]
12171336splitOn pat@(Text _ _ l) src@(Text arr off len)
12181337 | l <= 0 = emptyError "splitOn"
12191338 | isSingleton pat = split (== unsafeHead pat) src
12201339 | otherwise = go 0 (indices pat src)
12211340 where
1222− go !s (x:xs) = textP arr (s+off) (x-s) : go (x+l) xs
1223− go s _ = [textP arr (s+off) (len-s)]
1341+ go !s (x:xs) = text arr (s+off) (x-s) : go (x+l) xs
1342+ go s _ = [text arr (s+off) (len-s)]
12241343{-# INLINE [1] splitOn #-}
12251344
12261345{-# RULES
@@ -1312,7 +1431,7 @@ breakOn pat src@(Text arr off len)
13121431 | null pat = emptyError "breakOn"
13131432 | otherwise = case indices pat src of
13141433 [] -> (src, empty)
1315− (x:_) -> (textP arr off x, textP arr (off+x) (len-x))
1434+ (x:_) -> (text arr off x, text arr (off+x) (len-x))
13161435{-# INLINE breakOn #-}
13171436
13181437-- | /O(n+m)/ Similar to 'breakOn', but searches from the end of the
@@ -1354,7 +1473,7 @@ breakOnAll pat src@(Text arr off slen)
13541473 | otherwise = L.map step (indices pat src)
13551474 where
13561475 step x = (chunk 0 x, chunk x (slen-x))
1357− chunk !n !l = textP arr (n+off) l
1476+ chunk !n !l = text arr (n+off) l
13581477{-# INLINE breakOnAll #-}
13591478
13601479-------------------------------------------------------------------------------
@@ -1421,7 +1540,7 @@ countChar c t = S.countChar c (stream t)
14211540-- equivalent to a pair of 'unpack' operations.
14221541zip :: Text -> Text -> [(Char,Char)]
14231542zip a b = S.unstreamList $ S.zipWith (,) (stream a) (stream b)
1424−{-# INLINE [0] zip #-}
1543+{-# INLINE zip #-}
14251544
14261545-- | /O(n)/ 'zipWith' generalises 'zip' by zipping with the function
14271546-- given as the first argument, instead of a tupling function.
@@ -1429,7 +1548,7 @@ zip a b = S.unstreamList $ S.zipWith (,) (stream a) (stream b)
14291548zipWith :: (Char -> Char -> Char) -> Text -> Text -> Text
14301549zipWith f t1 t2 = unstream (S.zipWith g (stream t1) (stream t2))
14311550 where g a b = safe (f a b)
1432−{-# INLINE [0] zipWith #-}
1551+{-# INLINE zipWith #-}
14331552
14341553-- | /O(n)/ Breaks a 'Text' up into a list of words, delimited by 'Char's
14351554-- representing white space.
@@ -1554,7 +1673,7 @@ isInfixOf needle haystack
15541673-- > fnordLength _ = -1
15551674stripPrefix :: Text -> Text -> Maybe Text
15561675stripPrefix p@(Text _arr _off plen) t@(Text arr off len)
1557− | p `isPrefixOf` t = Just $! textP arr (off+plen) (len-plen)
1676+ | p `isPrefixOf` t = Just $! text arr (off+plen) (len-plen)
15581677 | otherwise = Nothing
15591678
15601679-- | /O(n)/ Find the longest non-empty common prefix of two strings
@@ -1574,8 +1693,8 @@ commonPrefixes t0@(Text arr0 off0 len0) t1@(Text arr1 off1 len1) = go 0 0
15741693 where
15751694 go !i !j | i < len0 && j < len1 && a == b = go (i+d0) (j+d1)
15761695 | i > 0 = Just (Text arr0 off0 i,
1577− textP arr0 (off0+i) (len0-i),
1578− textP arr1 (off1+j) (len1-j))
1696+ text arr0 (off0+i) (len0-i),
1697+ text arr1 (off1+j) (len1-j))
15791698 | otherwise = Nothing
15801699 where Iter a d0 = iter t0 i
15811700 Iter b d1 = iter t1 j
@@ -1600,7 +1719,7 @@ commonPrefixes t0@(Text arr0 off0 len0) t1@(Text arr1 off1 len1) = go 0 0
16001719-- > quuxLength _ = -1
16011720stripSuffix :: Text -> Text -> Maybe Text
16021721stripSuffix p@(Text _arr _off plen) t@(Text arr off len)
1603− | p `isSuffixOf` t = Just $! textP arr off (len-plen)
1722+ | p `isSuffixOf` t = Just $! text arr off (len-plen)
16041723 | otherwise = Nothing
16051724
16061725-- | Add a list of non-negative numbers. Errors out on overflow.
@@ -1629,6 +1748,7 @@ overflowError fun = P.error $ "Data.Text." ++ fun ++ ": size overflow"
16291748copy :: Text -> Text
16301749copy (Text arr off len) = Text (A.run go) 0 len
16311750 where
1751+ go :: ST s (A.MArray s)
16321752 go = do
16331753 marr <- A.new len
16341754 A.copyI marr 0 arr off len