@@ -1,48 +1,29 @@
1−{-# LANGUAGE BangPatterns, CPP, MagicHash, Rank2Types, UnboxedTuples #-}
1+{-# LANGUAGE BangPatterns, CPP, Rank2Types #-}
22{-# OPTIONS_GHC -fno-warn-orphans #-}
3−#if __GLASGOW_HASKELL__ >= 702
4−{-# LANGUAGE Trustworthy #-}
5−#endif
6−#if __GLASGOW_HASKELL__ >= 708
7−{-# LANGUAGE TypeFamilies #-}
8−#endif
93
104-- |
115-- Module : Data.Text
12−-- Copyright : (c) 2009, 2010, 2011, 2012 Bryan O'Sullivan,
13−-- (c) 2009 Duncan Coutts,
14−-- (c) 2008, 2009 Tom Harper
6+-- Copyright : (c) Tom Harper 2008-2009,
7+-- (c) Bryan O'Sullivan 2009,
8+-- (c) Duncan Coutts 2009
159--
1610-- License : BSD-style
17−-- Maintainer : bos@serpentine.com
11+-- Maintainer : bos@serpentine.com, rtomharper@googlemail.com,
12+-- duncan@haskell.org
1813-- Stability : experimental
1914-- Portability : GHC
2015--
21−-- A time and space-efficient implementation of Unicode text.
22−-- Suitable for performance critical use, both in terms of large data
23−-- quantities and high speed.
24−--
25−-- /Note/: Read below the synopsis for important notes on the use of
26−-- this module.
16+-- A time and space-efficient implementation of Unicode text using
17+-- packed Word16 arrays. Suitable for performance critical use, both
18+-- in terms of large data quantities and high speed.
2719--
2820-- This module is intended to be imported @qualified@, to avoid name
2921-- clashes with "Prelude" functions, e.g.
3022--
3123-- > import qualified Data.Text as T
32−--
33−-- To use an extended and very rich family of functions for working
34−-- with Unicode text (including normalization, regular expressions,
35−-- non-standard encodings, text breaking, and locales), see
36−-- <http://hackage.haskell.org/package/text-icu the text-icu package >.
3724
3825module Data.Text
3926 (
40− -- * Strict vs lazy types
41− -- $strict
42−
43− -- * Acceptable data
44− -- $replacement
45−
4627 -- * Fusion
4728 -- $fusion
4829
@@ -66,7 +47,6 @@ module Data.Text
6647 , init
6748 , null
6849 , length
69− , compareLength
7050
7151 -- * Transformations
7252 , map
@@ -81,7 +61,6 @@ module Data.Text
8161 , toCaseFold
8262 , toLower
8363 , toUpper
84− , toTitle
8564
8665 -- ** Justification
8766 , justifyLeft
@@ -125,11 +104,8 @@ module Data.Text
125104
126105 -- ** Breaking strings
127106 , take
128− , takeEnd
129107 , drop
130− , dropEnd
131108 , takeWhile
132− , takeWhileEnd
133109 , dropWhile
134110 , dropWhileEnd
135111 , dropAround
@@ -137,10 +113,10 @@ module Data.Text
137113 , stripStart
138114 , stripEnd
139115 , splitAt
140− , breakOn
141− , breakOnEnd
116+ , spanBy
142117 , break
143− , span
118+ , breakEnd
119+ , breakBy
144120 , group
145121 , groupBy
146122 , inits
@@ -148,8 +124,8 @@ module Data.Text
148124
149125 -- ** Breaking into many substrings
150126 -- $split
151− , splitOn
152127 , split
128+ , splitBy
153129 , chunksOf
154130
155131 -- ** Breaking into lines and words
@@ -164,309 +140,162 @@ module Data.Text
164140 , isSuffixOf
165141 , isInfixOf
166142
167− -- ** View patterns
168− , stripPrefix
169− , stripSuffix
170− , commonPrefixes
171−
172143 -- * Searching
173144 , filter
174− , breakOnAll
175145 , find
176− , partition
146+ , findBy
147+ , partitionBy
177148
178149 -- , findSubstring
179−
150+
180151 -- * Indexing
181152 -- $index
182153 , index
183154 , findIndex
184155 , count
185156
186− -- * Zipping
157+ -- * Zipping and unzipping
187158 , zip
188159 , zipWith
189160
190161 -- -* Ordered text
191162 -- , sort
192−
193− -- * Low level operations
194− , copy
195− , unpackCString#
196163 ) where
197164
198−import Prelude (Char, Bool(..), Int, Maybe(..), String,
199− Eq(..), Ord(..), Ordering(..), (++),
200− Read(..),
201− (&&), (||), (+), (-), (.), ($), ($!), (>>),
202− not, return, otherwise, quot)
165+import Prelude (Char, Bool(..), Functor(..), Int, Maybe(..), String,
166+ Eq(..), Ord(..), (++),
167+ Read(..), Show(..),
168+ (&&), (||), (+), (-), (.), ($), (>>), (*),
169+ div, error, not, return, otherwise)
203170#if defined(HAVE_DEEPSEQ)
204−import Control.DeepSeq (NFData(rnf))
171+import Control.DeepSeq (NFData)
205172#endif
206−#if defined(ASSERTS)
207173import Control.Exception (assert)
208−#endif
209174import Data.Char (isSpace)
210−import Data.Data (Data(gfoldl, toConstr, gunfold, dataTypeOf), constrIndex,
211− Constr, mkConstr, DataType, mkDataType, Fixity(Prefix))
175+import Data.Data (Data(gfoldl, toConstr, gunfold, dataTypeOf))
176+#if __GLASGOW_HASKELL__ >= 612
177+import Data.Data (mkNoRepType)
178+#else
179+import Data.Data (mkNorepType)
180+#endif
212181import Control.Monad (foldM)
213182import Control.Monad.ST (ST)
214183import qualified Data.Text.Array as A
215184import qualified Data.List as L
216−import Data.Binary (Binary(get, put))
217185import Data.Monoid (Monoid(..))
218−#if MIN_VERSION_base(4,9,0)
219−import Data.Semigroup (Semigroup(..))
220−#endif
186+import Data.Word (Word16)
221187import Data.String (IsString(..))
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#)
188+import qualified Data.Text.Fusion as S
189+import qualified Data.Text.Fusion.Common as S
190+import Data.Text.Fusion (stream, reverseStream, unstream)
191+import Data.Text.Internal (Text(..), empty, text, textP)
229192import qualified Prelude as P
230−import Data.Text.Unsafe (Iter(..), iter, iter_, lengthWord16, reverseIter,
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)
236−#if defined(__HADDOCK__)
237−import Data.ByteString (ByteString)
238−import qualified Data.Text.Lazy as L
239−import Data.Int (Int64)
240−#endif
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)
247−#endif
248−
249−-- $strict
250−--
251−-- This package provides both strict and lazy 'Text' types. 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
254−-- lazy @Text@ type consists of a list of strict chunks.
255−--
256−-- The strict 'Text' type requires that an entire string fit into
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.
264−--
265−-- Each module provides an almost identical API, with the main
266−-- difference being that the strict module uses 'Int' values for
267−-- lengths and counts, while the lazy module uses 'Data.Int.Int64'
268−-- lengths.
269−
270−-- $replacement
271−--
272−-- A 'Text' value is a sequence of Unicode scalar values, as defined
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.
283−--
284−-- Within this module, many functions construct a 'Text' from one or
285−-- more 'Char' values. Those functions will substitute 'Char' values
286−-- that are not valid Unicode scalar values with the replacement
287−-- character \"�\" (U+FFFD). Functions that perform this
288−-- inspection and replacement are documented with the phrase
289−-- \"Performs replacement on invalid scalar values\".
290−--
291−-- (One reason for this policy of replacement is that internally, a
292−-- 'Text' value is represented as packed UTF-16 data. Values in the
293−-- range U+D800 through U+DFFF are used by UTF-16 to denote surrogate
294−-- code points, and so cannot be represented. The functions replace
295−-- invalid scalar values, instead of dropping them, as a security
296−-- measure. For details, see
297−-- <http://unicode.org/reports/tr36/#Deletion_of_Noncharacters Unicode Technical Report 36, §3.5 >.)
193+import Data.Text.Unsafe (iter, iter_, reverseIter, unsafeHead, unsafeTail)
194+import Data.Text.UnsafeChar (unsafeChr)
195+import qualified Data.Text.Encoding.Utf16 as U16
196+import Data.Text.Search (indices)
298197
299198-- $fusion
300199--
301200-- Most of the functions in this module are subject to /fusion/,
302201-- meaning that a pipeline of such functions will usually allocate at
303202-- most one 'Text' value.
304−--
305−-- As an example, consider the following pipeline:
306−--
307−-- > import Data.Text as T
308−-- > import Data.Text.Encoding as E
309−-- > import Data.ByteString (ByteString)
310−-- >
311−-- > countChars :: ByteString -> Int
312−-- > countChars = T.length . T.toUpper . E.decodeUtf8
313−--
314−-- From the type signatures involved, this looks like it should
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'.
320−--
321−-- Functions that can be fused by the compiler are documented with the
322−-- phrase \"Subject to fusion\".
323203
324204instance Eq Text where
325− Text arrA offA lenA == Text arrB offB lenB
326− | lenA == lenB = A.equal arrA offA arrB offB lenA
327− | otherwise = False
205+ t1 == t2 = stream t1 == stream t2
328206 {-# INLINE (==) #-}
329207
330208instance Ord Text where
331− compare = compareText
209+ compare t1 t2 = compare (stream t1) (stream t2)
210+ {-# INLINE compare #-}
211+
212+instance Show Text where
213+ showsPrec p ps r = showsPrec p (unpack ps) r
332214
333215instance Read Text where
334216 readsPrec p str = [(pack x,y) | (x,y) <- readsPrec p str]
335217
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−
344218instance Monoid Text where
345219 mempty = empty
346−#if MIN_VERSION_base(4,9,0)
347− mappend = (<>) -- future-proof definition
348−#else
349220 mappend = append
350−#endif
351221 mconcat = concat
352222
353223instance IsString Text where
354224 fromString = pack
355225
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−
363226#if defined(HAVE_DEEPSEQ)
364−instance NFData Text where rnf !_ = ()
227+instance NFData Text
365228#endif
366229
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.
230+-- This instance preserves data abstraction at the cost of inefficiency.
376231-- We omit reflection services for the sake of data abstraction.
232+--
233+-- This instance was created by copying the behavior of Data.Set and
234+-- Data.Map. If you feel a mistake has been made, please feel free to
235+-- submit improvements.
377236--
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.
382−--
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, ... >
237+-- Original discussion is archived here:
238+
239+-- "could we get a Data instance for Data.Text.Text?"
240+-- http://groups.google.com/group/haskell-cafe/browse_thread/thread/b5bbb1b28a7e525d/0639d46852575b93
389241
390242instance Data Text where
391243 gfoldl f z txt = z pack `f` (unpack txt)
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
244+ toConstr _ = error "Data.Text.Text.toConstr"
245+ gunfold _ _ = error "Data.Text.Text.gunfold"
246+#if __GLASGOW_HASKELL__ >= 612
247+ dataTypeOf _ = mkNoRepType "Data.Text.Text"
248+#else
249+ dataTypeOf _ = mkNorepType "Data.Text.Text"
402250#endif
403251
404−packConstr :: Constr
405−packConstr = mkConstr textDataType "pack" [] Prefix
406−
407−textDataType :: DataType
408−textDataType = mkDataType "Data.Text.Text" [packConstr]
409−
410−-- | /O(n)/ Compare two 'Text' values lexicographically.
411−compareText :: Text -> Text -> Ordering
412−compareText ta@(Text _arrA _offA lenA) tb@(Text _arrB _offB lenB)
413− | lenA == 0 && lenB == 0 = EQ
414− | otherwise = go 0 0
415− where
416− go !i !j
417− | i >= lenA || j >= lenB = compare lenA lenB
418− | a < b = LT
419− | a > b = GT
420− | otherwise = go (i+di) (j+dj)
421− where Iter a di = iter ta i
422− Iter b dj = iter tb j
423−
424252-- -----------------------------------------------------------------------------
425253-- * Conversion to/from 'Text'
426254
427−-- | /O(n)/ Convert a 'String' into a 'Text'. Subject to
428−-- fusion. Performs replacement on invalid scalar values.
255+-- | /O(n)/ Convert a 'String' into a 'Text'. Subject to fusion.
429256pack :: String -> Text
430−pack = unstream . S.map safe . S.streamList
257+pack = unstream . S.streamList
431258{-# INLINE [1] pack #-}
432259
260+-- | /O(n)/ Convert a Text into a String. Subject to fusion.
261+unpack :: Text -> String
262+unpack = S.unstreamList . stream
263+{-# INLINE [1] unpack #-}
264+
265+-- | /O(1)/ Convert a character into a Text.
266+-- Subject to fusion.
267+singleton :: Char -> Text
268+singleton = unstream . S.singleton
269+{-# INLINE [1] singleton #-}
270+
433271-- -----------------------------------------------------------------------------
434272-- * Basic functions
435273
436274-- | /O(n)/ Adds a character to the front of a 'Text'. This function
437275-- is more costly than its 'List' counterpart because it requires
438−-- copying a new array. Subject to fusion. Performs replacement on
439−-- invalid scalar values.
276+-- copying a new array. Subject to fusion.
440277cons :: Char -> Text -> Text
441−cons c t = unstream (S.cons (safe c) (stream t))
278+cons c t = unstream (S.cons c (stream t))
442279{-# INLINE cons #-}
443280
444−infixr 5 `cons`
445−
446281-- | /O(n)/ Adds a character to the end of a 'Text'. This copies the
447282-- entire array in the process, unless fused. Subject to fusion.
448−-- Performs replacement on invalid scalar values.
449283snoc :: Text -> Char -> Text
450−snoc t c = unstream (S.snoc (stream t) (safe c))
284+snoc t c = unstream (S.snoc (stream t) c)
451285{-# INLINE snoc #-}
452286
453287-- | /O(n)/ Appends one 'Text' to the other by copying both of them
454288-- into a new 'Text'. Subject to fusion.
455289append :: Text -> Text -> Text
456−append a@(Text arr1 off1 len1) b@(Text arr2 off2 len2)
457− | len1 == 0 = b
458− | len2 == 0 = a
459− | len > 0 = Text (A.run x) 0 len
460− | otherwise = overflowError "append"
290+append (Text arr1 off1 len1) (Text arr2 off2 len2) = Text (A.run x) 0 len
461291 where
462292 len = len1+len2
463− x :: ST s (A.MArray s)
464293 x = do
465− arr <- A.new len
466− A.copyI arr 0 arr1 off1 len1
467− A.copyI arr len1 arr2 off2 len
294+ arr <- A.unsafeNew len
295+ copy arr 0 arr1 off1 len1
296+ copy arr len1 arr2 off2 (len1+len2)
468297 return arr
469−{-# NOINLINE append #-}
298+{-# INLINE append #-}
470299
471300{-# RULES
472301"TEXT append -> fused" [~1] forall t1 t2.
@@ -475,6 +304,14 @@ append a@(Text arr1 off1 len1) b@(Text arr2 off2 len2)
475304 unstream (S.append (stream t1) (stream t2)) = append t1 t2
476305 #-}
477306
307+copy :: forall s. A.MArray s Word16 -> Int -> A.Array Word16 -> Int -> Int
308+ -> ST s ()
309+copy dest i0 src j0 top = go i0 j0
310+ where
311+ go i j | i >= top = return ()
312+ | otherwise = do A.unsafeWrite dest i (src `A.unsafeIndex` j)
313+ go (i+1) (j+1)
314+
478315-- | /O(1)/ Returns the first character of a 'Text', which must be
479316-- non-empty. Subject to fusion.
480317head :: Text -> Char
@@ -486,14 +323,21 @@ head t = S.head (stream t)
486323uncons :: Text -> Maybe (Char, Text)
487324uncons t@(Text arr off len)
488325 | len <= 0 = Nothing
489− | otherwise = Just $ let !(Iter c d) = iter t 0
490− in (c, text arr (off+d) (len-d))
326+ | otherwise = Just (c, textP arr (off+d) (len-d))
327+ where (c,d) = iter t 0
491328{-# INLINE [1] uncons #-}
492329
493330-- | Lifted from Control.Arrow and specialized.
494331second :: (b -> c) -> (a,b) -> (a,c)
495332second f (a, b) = (a, f b)
496333
334+{-# RULES
335+"TEXT uncons -> fused" [~1] forall t.
336+ uncons t = fmap (second unstream) (S.uncons (stream t))
337+"TEXT uncons -> unfused" [1] forall t.
338+ fmap (second unstream) (S.uncons (stream t)) = uncons t
339+ #-}
340+
497341-- | /O(1)/ Returns the last character of a 'Text', which must be
498342-- non-empty. Subject to fusion.
499343last :: Text -> Char
@@ -517,7 +361,7 @@ last (Text arr off len)
517361tail :: Text -> Text
518362tail t@(Text arr off len)
519363 | len <= 0 = emptyError "tail"
520− | otherwise = text arr (off+d) (len-d)
364+ | otherwise = textP arr (off+d) (len-d)
521365 where d = iter_ t 0
522366{-# INLINE [1] tail #-}
523367
@@ -532,8 +376,8 @@ tail t@(Text arr off len)
532376-- be non-empty. Subject to fusion.
533377init :: Text -> Text
534378init (Text arr off len) | len <= 0 = emptyError "init"
535− | n >= 0xDC00 && n <= 0xDFFF = text arr off (len-2)
536− | otherwise = text arr off (len-1)
379+ | n >= 0xDC00 && n <= 0xDFFF = textP arr off (len-2)
380+ | otherwise = textP arr off (len-1)
537381 where
538382 n = A.unsafeIndex arr (off+len-1)
539383{-# INLINE [1] init #-}
@@ -548,11 +392,7 @@ init (Text arr off len) | len <= 0 = emptyError "init"
548392-- | /O(1)/ Tests whether a 'Text' is empty or not. Subject to
549393-- fusion.
550394null :: Text -> Bool
551−null (Text _arr _off len) =
552−#if defined(ASSERTS)
553− assert (len >= 0) $
554−#endif
555− len <= 0
395+null (Text _arr _off len) = assert (len >= 0) $ len <= 0
556396{-# INLINE [1] null #-}
557397
558398{-# RULES
@@ -572,76 +412,27 @@ isSingleton = S.isSingleton . stream
572412-- Subject to fusion.
573413length :: Text -> Int
574414length t = S.length (stream t)
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.
578−
579−-- | /O(n)/ Compare the count of characters in a 'Text' to a number.
580−-- Subject to fusion.
581−--
582−-- This function gives the same answer as comparing against the result
583−-- of 'length', but can short circuit if the count of characters is
584−-- greater than the number, and hence be more efficient.
585−compareLength :: Text -> Int -> Ordering
586−compareLength t n = S.compareLengthI (stream t) n
587−{-# INLINE [1] compareLength #-}
588−
589−{-# RULES
590−"TEXT compareN/length -> compareLength" [~1] forall t n.
591− compare (length t) n = compareLength t n
592− #-}
593−
594−{-# RULES
595−"TEXT ==N/length -> compareLength/==EQ" [~1] forall t n.
596− eqInt (length t) n = compareLength t n == EQ
597− #-}
598−
599−{-# RULES
600−"TEXT /=N/length -> compareLength//=EQ" [~1] forall t n.
601− neInt (length t) n = compareLength t n /= EQ
602− #-}
603−
604−{-# RULES
605−"TEXT <N/length -> compareLength/==LT" [~1] forall t n.
606− ltInt (length t) n = compareLength t n == LT
607− #-}
608−
609−{-# RULES
610−"TEXT <=N/length -> compareLength//=GT" [~1] forall t n.
611− leInt (length t) n = compareLength t n /= GT
612− #-}
613−
614−{-# RULES
615−"TEXT >N/length -> compareLength/==GT" [~1] forall t n.
616− gtInt (length t) n = compareLength t n == GT
617− #-}
618−
619−{-# RULES
620−"TEXT >=N/length -> compareLength//=LT" [~1] forall t n.
621− geInt (length t) n = compareLength t n /= LT
622− #-}
415+{-# INLINE length #-}
623416
624417-- -----------------------------------------------------------------------------
625418-- * Transformations
626419-- | /O(n)/ 'map' @f@ @t@ is the 'Text' obtained by applying @f@ to
627−-- each element of @t@. Subject to fusion. Performs replacement on
628−-- invalid scalar values.
420+-- each element of @t@. Subject to fusion.
629421map :: (Char -> Char) -> Text -> Text
630−map f t = unstream (S.map (safe . f) (stream t))
422+map f t = unstream (S.map f (stream t))
631423{-# INLINE [1] map #-}
632424
633425-- | /O(n)/ The 'intercalate' function takes a 'Text' and a list of
634426-- 'Text's and concatenates the list after interspersing the first
635427-- argument between each element of the list.
636428intercalate :: Text -> [Text] -> Text
637−intercalate t = concat . (F.intersperse t)
429+intercalate t = concat . (L.intersperse t)
638430{-# INLINE intercalate #-}
639431
640432-- | /O(n)/ The 'intersperse' function takes a character and places it
641−-- between the characters of a 'Text'. Subject to fusion. Performs
642−-- replacement on invalid scalar values.
433+-- between the characters of a 'Text'. Subject to fusion.
643434intersperse :: Char -> Text -> Text
644−intersperse c t = unstream (S.intersperse (safe c) (stream t))
435+intersperse c t = unstream (S.intersperse c (stream t))
645436{-# INLINE intersperse #-}
646437
647438-- | /O(n)/ Reverse the characters of a string. Subject to fusion.
@@ -649,59 +440,13 @@ reverse :: Text -> Text
649440reverse t = S.reverse (stream t)
650441{-# INLINE reverse #-}
651442
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"
672−--
673−-- In (unlikely) bad cases, this function's time complexity degrades
674−-- towards /O(n*m)/.
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.
443+-- | /O(m+n)/ Replace every occurrence of one substring with another.
444+replace :: Text -- ^ Text to search for
445+ -> Text -- ^ Replacement text
446+ -> Text -- ^ Input text
682447 -> Text
683−replace needle@(Text _ _ neeLen)
684− (Text repArr repOff repLen)
685− haystack@(Text hayArr hayOff hayLen)
686− | neeLen == 0 = emptyError "replace"
687− | L.null ixs = haystack
688− | len > 0 = Text (A.run x) 0 len
689− | otherwise = empty
690− where
691− ixs = indices needle haystack
692− len = hayLen - (neeLen - repLen) `mul` L.length ixs
693− x :: ST s (A.MArray s)
694− x = do
695− marr <- A.new len
696− let loop (i:is) o d = do
697− let d0 = d + i - o
698− d1 = d0 + repLen
699− A.copyI marr d hayArr (hayOff+o) d0
700− A.copyI marr d0 repArr repOff d1
701− loop is (i + neeLen) d1
702− loop [] o d = A.copyI marr d hayArr (hayOff+o) len
703− loop ixs 0 0
704− return marr
448+replace s d = intercalate d . split s
449+{-# INLINE replace #-}
705450
706451-- ----------------------------------------------------------------------------
707452-- ** Case conversions (folds)
@@ -716,17 +461,10 @@ replace needle@(Text _ _ neeLen)
716461-- case conversion rules. As a result, these functions may map one
717462-- input character to two or three output characters. For examples,
718463-- see the documentation of each function.
719−--
720−-- /Note/: In some languages, case conversion is a locale- and
721−-- context-dependent operation. The case conversion functions in this
722−-- module are /not/ locale sensitive. Programs that require locale
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 >.
725464
726−-- | /O(n)/ Convert a string to folded case. Subject to fusion.
727−--
728−-- This function is mainly useful for performing caseless (also known
729−-- as case insensitive) string comparisons.
465+-- | /O(n)/ Convert a string to folded case. This function is mainly
466+-- useful for performing caseless (also known as case insensitive)
467+-- string comparisons.
730468--
731469-- A string @x@ is a caseless match for a string @y@ if and only if:
732470--
@@ -741,56 +479,27 @@ replace needle@(Text _ _ neeLen)
741479-- instead of itself.
742480toCaseFold :: Text -> Text
743481toCaseFold t = unstream (S.toCaseFold (stream t))
744−{-# INLINE toCaseFold #-}
482+{-# INLINE [0] toCaseFold #-}
745483
746484-- | /O(n)/ Convert a string to lower case, using simple case
747−-- conversion. Subject to fusion.
748−--
749−-- The result string may be longer than the input string. For
750−-- instance, \"İ\" (Latin capital letter I with dot above,
751−-- U+0130) maps to the sequence \"i\" (Latin small letter i, U+0069)
752−-- followed by \" ̇\" (combining dot above, U+0307).
485+-- conversion. The result string may be longer than the input string.
486+-- For instance, \"İ\" (Latin capital letter I with dot above,
487+-- U+0130) maps to the sequence \"i\" (Latin small letter i, U+0069) followed
488+-- by \" ̇\" (combining dot above, U+0307).
753489toLower :: Text -> Text
754490toLower t = unstream (S.toLower (stream t))
755491{-# INLINE toLower #-}
756492
757493-- | /O(n)/ Convert a string to upper case, using simple case
758−-- conversion. Subject to fusion.
759−--
760−-- The result string may be longer than the input string. For
761−-- instance, the German \"ß\" (eszett, U+00DF) maps to the
494+-- conversion. The result string may be longer than the input string.
495+-- For instance, the German \"ß\" (eszett, U+00DF) maps to the
762496-- two-letter sequence \"SS\".
763497toUpper :: Text -> Text
764498toUpper t = unstream (S.toUpper (stream t))
765499{-# INLINE toUpper #-}
766500
767−-- | /O(n)/ Convert a string to title case, using simple case
768−-- conversion. Subject to fusion.
769−--
770−-- The first letter of the input is converted to title case, as is
771−-- every subsequent letter that immediately follows a non-letter.
772−-- Every letter that immediately follows another letter is converted
773−-- to lower case.
774−--
775−-- The result string may be longer than the input string. For example,
776−-- the Latin small ligature fl (U+FB02) is converted to the
777−-- sequence Latin capital letter F (U+0046) followed by Latin small
778−-- letter l (U+006C).
779−--
780−-- /Note/: this function does not take language or culture specific
781−-- rules into account. For instance, in English, different style
782−-- guides disagree on whether the book name \"The Hill of the Red
783−-- Fox\" is correctly title cased—but this function will
784−-- capitalize /every/ word.
785−toTitle :: Text -> Text
786−toTitle t = unstream (S.toTitle (stream t))
787−{-# INLINE toTitle #-}
788−
789501-- | /O(n)/ Left-justify a string to the given length, using the
790−-- specified fill character on the right. Subject to fusion.
791−-- Performs replacement on invalid scalar values.
792−--
793−-- Examples:
502+-- specified fill character on the right. Subject to fusion. Examples:
794503--
795504-- > justifyLeft 7 'x' "foo" == "fooxxxx"
796505-- > justifyLeft 3 'x' "foobar" == "foobar"
@@ -809,10 +518,7 @@ justifyLeft k c t
809518 #-}
810519
811520-- | /O(n)/ Right-justify a string to the given length, using the
812−-- specified fill character on the left. Performs replacement on
813−-- invalid scalar values.
814−--
815−-- Examples:
521+-- specified fill character on the left. Examples:
816522--
817523-- > justifyRight 7 'x' "bar" == "xxxxbar"
818524-- > justifyRight 3 'x' "foobar" == "foobar"
@@ -823,11 +529,8 @@ justifyRight k c t
823529 where len = length t
824530{-# INLINE justifyRight #-}
825531
826−-- | /O(n)/ Center a string to the given length, using the specified
827−-- fill character on either side. Performs replacement on invalid
828−-- scalar values.
829−--
830−-- Examples:
532+-- | /O(n)/ Center a string to the given length, using the
533+-- specified fill character on either side. Examples:
831534--
832535-- > center 8 'x' "HS" = "xxxHSxxx"
833536center :: Int -> Char -> Text -> Text
@@ -836,7 +539,7 @@ center k c t
836539 | otherwise = replicateChar l c `append` t `append` replicateChar r c
837540 where len = length t
838541 d = k - len
839− r = d `quot` 2
542+ r = d `div` 2
840543 l = d - r
841544{-# INLINE center #-}
842545
@@ -854,12 +557,12 @@ transpose ts = P.map pack (L.transpose (P.map unpack ts))
854557-- (typically the left-identity of the operator), and a 'Text',
855558-- reduces the 'Text' using the binary operator, from left to right.
856559-- Subject to fusion.
857−foldl :: (a -> Char -> a) -> a -> Text -> a
560+foldl :: (b -> Char -> b) -> b -> Text -> b
858561foldl f z t = S.foldl f z (stream t)
859562{-# INLINE foldl #-}
860563
861564-- | /O(n)/ A strict version of 'foldl'. Subject to fusion.
862−foldl' :: (a -> Char -> a) -> a -> Text -> a
565+foldl' :: (b -> Char -> b) -> b -> Text -> b
863566foldl' f z t = S.foldl' f z (stream t)
864567{-# INLINE foldl' #-}
865568
@@ -878,12 +581,12 @@ foldl1' f t = S.foldl1' f (stream t)
878581-- (typically the right-identity of the operator), and a 'Text',
879582-- reduces the 'Text' using the binary operator, from right to left.
880583-- Subject to fusion.
881−foldr :: (Char -> a -> a) -> a -> Text -> a
584+foldr :: (Char -> b -> b) -> b -> Text -> b
882585foldr f z t = S.foldr f z (stream t)
883586{-# INLINE foldr #-}
884587
885588-- | /O(n)/ A variant of 'foldr' that has no starting value argument,
886−-- and thus must be applied to a non-empty 'Text'. Subject to
589+-- and thust must be applied to a non-empty 'Text'. Subject to
887590-- fusion.
888591foldr1 :: (Char -> Char -> Char) -> Text -> Char
889592foldr1 f t = S.foldr1 f (stream t)
@@ -894,19 +597,14 @@ foldr1 f t = S.foldr1 f (stream t)
894597
895598-- | /O(n)/ Concatenate a list of 'Text's.
896599concat :: [Text] -> Text
897−concat ts = case ts' of
898− [] -> empty
899− [t] -> t
900− _ -> Text (A.run go) 0 len
600+concat ts = Text (A.run go) 0 len
901601 where
902− ts' = L.filter (not . null) ts
903− len = sumP "concat" $ L.map lengthWord16 ts'
904− go :: ST s (A.MArray s)
602+ len = L.sum (L.map (\(Text _ _ l) -> l) ts)
905603 go = do
906− arr <- A.new len
907− let step i (Text a o l) =
908− let !j = i + l in A.copyI arr i a o j >> return j
909− foldM step 0 ts' >> return arr
604+ arr <- A.unsafeNew len
605+ let step i (Text a o l) = let j = i + l in copy arr i a o j >> return j
606+ foldM step 0 ts >> return arr
607+{-# INLINE concat #-}
910608
911609-- | /O(n)/ Map a function over a 'Text' that results in a 'Text', and
912610-- concatenate the results.
@@ -915,13 +613,13 @@ concatMap f = concat . foldr ((:) . f) []
915613{-# INLINE concatMap #-}
916614
917615-- | /O(n)/ 'any' @p@ @t@ determines whether any character in the
918−-- 'Text' @t@ satisfies the predicate @p@. Subject to fusion.
616+-- 'Text' @t@ satisifes the predicate @p@. Subject to fusion.
919617any :: (Char -> Bool) -> Text -> Bool
920618any p t = S.any p (stream t)
921619{-# INLINE any #-}
922620
923621-- | /O(n)/ 'all' @p@ @t@ determines whether all characters in the
924−-- 'Text' @t@ satisfy the predicate @p@. Subject to fusion.
622+-- 'Text' @t@ satisify the predicate @p@. Subject to fusion.
925623all :: (Char -> Bool) -> Text -> Bool
926624all p t = S.all p (stream t)
927625{-# INLINE all #-}
@@ -943,7 +641,6 @@ minimum t = S.minimum (stream t)
943641
944642-- | /O(n)/ 'scanl' is similar to 'foldl', but returns a list of
945643-- successive reduced values from the left. Subject to fusion.
946−-- Performs replacement on invalid scalar values.
947644--
948645-- > scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]
949646--
@@ -951,13 +648,11 @@ minimum t = S.minimum (stream t)
951648--
952649-- > last (scanl f z xs) == foldl f z xs.
953650scanl :: (Char -> Char -> Char) -> Char -> Text -> Text
954−scanl f z t = unstream (S.scanl g z (stream t))
955− where g a b = safe (f a b)
651+scanl f z t = unstream (S.scanl f z (stream t))
956652{-# INLINE scanl #-}
957653
958654-- | /O(n)/ 'scanl1' is a variant of 'scanl' that has no starting
959−-- value argument. Subject to fusion. Performs replacement on
960−-- invalid scalar values.
655+-- value argument. Subject to fusion.
961656--
962657-- > scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]
963658scanl1 :: (Char -> Char -> Char) -> Text -> Text
@@ -965,42 +660,40 @@ scanl1 f t | null t = empty
965660 | otherwise = scanl f (unsafeHead t) (unsafeTail t)
966661{-# INLINE scanl1 #-}
967662
968−-- | /O(n)/ 'scanr' is the right-to-left dual of 'scanl'. Performs
969−-- replacement on invalid scalar values.
663+-- | /O(n)/ 'scanr' is the right-to-left dual of 'scanl'.
970664--
971665-- > scanr f v == reverse . scanl (flip f) v . reverse
972666scanr :: (Char -> Char -> Char) -> Char -> Text -> Text
973−scanr f z = S.reverse . S.reverseScanr g z . reverseStream
974− where g a b = safe (f a b)
667+scanr f z = S.reverse . S.reverseScanr f z . reverseStream
975668{-# INLINE scanr #-}
976669
977670-- | /O(n)/ 'scanr1' is a variant of 'scanr' that has no starting
978−-- value argument. Subject to fusion. Performs replacement on
979−-- invalid scalar values.
671+-- value argument. Subject to fusion.
980672scanr1 :: (Char -> Char -> Char) -> Text -> Text
981673scanr1 f t | null t = empty
982674 | otherwise = scanr f (last t) (init t)
983675{-# INLINE scanr1 #-}
984676
985−-- | /O(n)/ Like a combination of 'map' and 'foldl''. Applies a
677+-- | /O(n)/ Like a combination of 'map' and 'foldl'. Applies a
986678-- function to each element of a 'Text', passing an accumulating
987−-- parameter from left to right, and returns a final 'Text'. Performs
988−-- replacement on invalid scalar values.
679+-- parameter from left to right, and returns a final 'Text'.
989680mapAccumL :: (a -> Char -> (a,Char)) -> a -> Text -> (a, Text)
990−mapAccumL f z0 = S.mapAccumL g z0 . stream
991− where g a b = second safe (f a b)
992−{-# INLINE mapAccumL #-}
681+mapAccumL f s t = case uncons t of
682+ Nothing -> (s, empty)
683+ Just (x, xs) -> (s'', cons y ys)
684+ where (s', y ) = f s x
685+ (s'',ys) = mapAccumL f s' xs
993686
994687-- | The 'mapAccumR' function behaves like a combination of 'map' and
995−-- a strict 'foldr'; it applies a function to each element of a
996−-- 'Text', passing an accumulating parameter from right to left, and
997−-- returning a final value of this accumulator together with the new
998−-- 'Text'.
999−-- Performs replacement on invalid scalar values.
688+-- 'foldr'; it applies a function to each element of a 'Text', passing
689+-- an accumulating parameter from right to left, and returning a final
690+-- value of this accumulator together with the new 'Text'.
1000691mapAccumR :: (a -> Char -> (a,Char)) -> a -> Text -> (a, Text)
1001−mapAccumR f z0 = second reverse . S.mapAccumL g z0 . reverseStream
1002− where g a b = second safe (f a b)
1003−{-# INLINE mapAccumR #-}
692+mapAccumR f s t = case uncons t of
693+ Nothing -> (s, empty)
694+ Just (x, xs) -> (s'', cons y ys)
695+ where (s'',y ) = f s' x
696+ (s', ys) = mapAccumR f s xs
1004697
1005698-- -----------------------------------------------------------------------------
1006699-- ** Generating and unfolding 'Text's
@@ -1009,18 +702,17 @@ mapAccumR f z0 = second reverse . S.mapAccumL g z0 . reverseStream
1009702-- @t@ repeated @n@ times.
1010703replicate :: Int -> Text -> Text
1011704replicate n t@(Text a o l)
1012− | n <= 0 || l <= 0 = empty
1013− | n == 1 = t
1014− | isSingleton t = replicateChar n (unsafeHead t)
1015− | otherwise = Text (A.run x) 0 len
705+ | n <= 0 || l <= 0 = empty
706+ | n == 1 = t
707+ | isSingleton t = replicateChar n (unsafeHead t)
708+ | otherwise = Text (A.run x) 0 len
1016709 where
1017− len = l `mul` n
1018− x :: ST s (A.MArray s)
710+ len = l * n
1019711 x = do
1020− arr <- A.new len
712+ arr <- A.unsafeNew len
1021713 let loop !d !i | i >= n = return arr
1022714 | otherwise = let m = d + l
1023− in A.copyI arr d a o m >> loop m (i+1)
715+ in copy arr d a o m >> loop m (i+1)
1024716 loop 0 0
1025717{-# INLINE [1] replicate #-}
1026718
@@ -1032,7 +724,7 @@ replicate n t@(Text a o l)
1032724-- | /O(n)/ 'replicateChar' @n@ @c@ is a 'Text' of length @n@ with @c@ the
1033725-- value of every element. Subject to fusion.
1034726replicateChar :: Int -> Char -> Text
1035−replicateChar n c = unstream (S.replicateCharI n (safe c))
727+replicateChar n c = unstream (S.replicateCharI n c)
1036728{-# INLINE replicateChar #-}
1037729
1038730-- | /O(n)/, where @n@ is the length of the result. The 'unfoldr'
@@ -1041,9 +733,9 @@ replicateChar n c = unstream (S.replicateCharI n (safe c))
1041733-- returns 'Nothing' if it is done producing the 'Text', otherwise
1042734-- 'Just' @(a,b)@. In this case, @a@ is the next 'Char' in the
1043735-- string, and @b@ is the seed value for further production. Subject
1044−-- to fusion. Performs replacement on invalid scalar values.
736+-- to fusion.
1045737unfoldr :: (a -> Maybe (Char,a)) -> a -> Text
1046−unfoldr f s = unstream (S.unfoldr (firstf safe . f) s)
738+unfoldr f s = unstream (S.unfoldr f s)
1047739{-# INLINE unfoldr #-}
1048740
1049741-- | /O(n)/ Like 'unfoldr', 'unfoldrN' builds a 'Text' from a seed
@@ -1051,9 +743,9 @@ unfoldr f s = unstream (S.unfoldr (firstf safe . f) s)
1051743-- first argument to 'unfoldrN'. This function is more efficient than
1052744-- 'unfoldr' when the maximum length of the result is known and
1053745-- correct, otherwise its performance is similar to 'unfoldr'. Subject
1054−-- to fusion. Performs replacement on invalid scalar values.
746+-- to fusion.
1055747unfoldrN :: Int -> (a -> Maybe (Char,a)) -> a -> Text
1056−unfoldrN n f s = unstream (S.unfoldrN n (firstf safe . f) s)
748+unfoldrN n f s = unstream (S.unfoldrN n f s)
1057749{-# INLINE unfoldrN #-}
1058750
1059751-- -----------------------------------------------------------------------------
@@ -1066,16 +758,14 @@ take :: Int -> Text -> Text
1066758take n t@(Text arr off len)
1067759 | n <= 0 = empty
1068760 | n >= len = t
1069− | otherwise = text arr off (iterN n t)
761+ | otherwise = Text arr off (loop 0 0)
762+ where
763+ loop !i !cnt
764+ | i >= len || cnt >= n = i
765+ | otherwise = loop (i+d) (cnt+1)
766+ where d = iter_ t i
1070767{-# INLINE [1] take #-}
1071768
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−
1079769{-# RULES
1080770"TEXT take -> fused" [~1] forall n t.
1081771 take n t = unstream (S.take n (stream t))
@@ -1083,36 +773,18 @@ iterN n t@(Text _arr _off len) = loop 0 0
1083773 unstream (S.take n (stream t)) = take n t
1084774 #-}
1085775
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−
1107776-- | /O(n)/ 'drop' @n@, applied to a 'Text', returns the suffix of the
1108−-- 'Text' after the first @n@ characters, or the empty 'Text' if @n@
1109−-- is greater than the length of the 'Text'. Subject to fusion.
777+-- 'Text' of length @n@, or the empty 'Text' if @n@ is greater than the
778+-- length of the 'Text'. Subject to fusion.
1110779drop :: Int -> Text -> Text
1111780drop n t@(Text arr off len)
1112781 | n <= 0 = t
1113782 | n >= len = empty
1114− | otherwise = text arr (off+i) (len-i)
1115− where i = iterN n t
783+ | otherwise = loop 0 0
784+ where loop !i !cnt
785+ | i >= len || cnt >= n = Text arr (off+i) (len-i)
786+ | otherwise = loop (i+d) (cnt+1)
787+ where d = iter_ t i
1116788{-# INLINE [1] drop #-}
1117789
1118790{-# RULES
@@ -1122,18 +794,6 @@ drop n t@(Text arr off len)
1122794 unstream (S.drop n (stream t)) = drop n t
1123795 #-}
1124796
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−
1137797-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text',
1138798-- returns the longest prefix (possibly empty) of elements that
1139799-- satisfy @p@. Subject to fusion.
@@ -1141,8 +801,8 @@ takeWhile :: (Char -> Bool) -> Text -> Text
1141801takeWhile p t@(Text arr off len) = loop 0
1142802 where loop !i | i >= len = t
1143803 | p c = loop (i+d)
1144− | otherwise = text arr off i
1145− where Iter c d = iter t i
804+ | otherwise = textP arr off i
805+ where (c,d) = iter t i
1146806{-# INLINE [1] takeWhile #-}
1147807
1148808{-# RULES
@@ -1152,27 +812,6 @@ takeWhile p t@(Text arr off len) = loop 0
1152812 unstream (S.takeWhile p (stream t)) = takeWhile p t
1153813 #-}
1154814
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−
1176815-- | /O(n)/ 'dropWhile' @p@ @t@ returns the suffix remaining after
1177816-- 'takeWhile' @p@ @t@. Subject to fusion.
1178817dropWhile :: (Char -> Bool) -> Text -> Text
@@ -1180,7 +819,7 @@ dropWhile p t@(Text arr off len) = loop 0 0
1180819 where loop !i !l | l >= len = empty
1181820 | p c = loop (i+d) (l+d)
1182821 | otherwise = Text arr (off+i) (len-l)
1183− where Iter c d = iter t i
822+ where (c,d) = iter t i
1184823{-# INLINE [1] dropWhile #-}
1185824
1186825{-# RULES
@@ -1191,9 +830,8 @@ dropWhile p t@(Text arr off len) = loop 0 0
1191830 #-}
1192831
1193832-- | /O(n)/ 'dropWhileEnd' @p@ @t@ returns the prefix remaining after
1194−-- dropping characters that satisfy the predicate @p@ from the end of
833+-- dropping characters that fail the predicate @p@ from the end of
1195834-- @t@. Subject to fusion.
1196−--
1197835-- Examples:
1198836--
1199837-- > dropWhileEnd (=='.') "foo..." == "foo"
@@ -1213,7 +851,7 @@ dropWhileEnd p t@(Text arr off len) = loop (len-1) len
1213851 #-}
1214852
1215853-- | /O(n)/ 'dropAround' @p@ @t@ returns the substring remaining after
1216−-- dropping characters that satisfy the predicate @p@ from both the
854+-- dropping characters that fail the predicate @p@ from both the
1217855-- beginning and end of @t@. Subject to fusion.
1218856dropAround :: (Char -> Bool) -> Text -> Text
1219857dropAround p = dropWhile p . dropWhileEnd p
@@ -1248,23 +886,31 @@ splitAt :: Int -> Text -> (Text, Text)
1248886splitAt n t@(Text arr off len)
1249887 | n <= 0 = (empty, t)
1250888 | n >= len = (t, empty)
1251− | otherwise = let k = iterN n t
1252− in (text arr off k, text arr (off+k) (len-k))
889+ | otherwise = (Text arr off k, Text arr (off+k) (len-k))
890+ where k = loop 0 0
891+ loop !i !cnt
892+ | i >= len || cnt >= n = i
893+ | otherwise = loop (i+d) (cnt+1)
894+ where d = iter_ t i
895+{-# INLINE splitAt #-}
1253896
1254−-- | /O(n)/ 'span', applied to a predicate @p@ and text @t@, returns
897+-- | /O(n)/ 'spanBy', applied to a predicate @p@ and text @t@, returns
1255898-- a pair whose first element is the longest prefix (possibly empty)
1256899-- of @t@ of elements that satisfy @p@, and whose second is the
1257900-- remainder of the list.
1258−span :: (Char -> Bool) -> Text -> (Text, Text)
1259−span p t = case span_ p t of
1260− (# hd,tl #) -> (hd,tl)
1261−{-# INLINE span #-}
1262−
1263−-- | /O(n)/ 'break' is like 'span', but the prefix returned is
901+spanBy :: (Char -> Bool) -> Text -> (Text, Text)
902+spanBy p t@(Text arr off len) = (textP arr off k, textP arr (off+k) (len-k))
903+ where k = loop 0
904+ loop !i | i >= len || not (p c) = i
905+ | otherwise = loop (i+d)
906+ where (c,d) = iter t i
907+{-# INLINE spanBy #-}
908+
909+-- | /O(n)/ 'breakBy' is like 'spanBy', but the prefix returned is
1264910-- over elements that fail the predicate @p@.
1265−break :: (Char -> Bool) -> Text -> (Text, Text)
1266−break p = span (not . p)
1267−{-# INLINE break #-}
911+breakBy :: (Char -> Bool) -> Text -> (Text, Text)
912+breakBy p = spanBy (not . p)
913+{-# INLINE breakBy #-}
1268914
1269915-- | /O(n)/ Group characters in a string according to a predicate.
1270916groupBy :: (Char -> Char -> Bool) -> Text -> [Text]
@@ -1273,7 +919,7 @@ groupBy p = loop
1273919 loop t@(Text arr off len)
1274920 | null t = []
1275921 | otherwise = text arr off n : loop (text arr (off+n) (len-n))
1276− where Iter c d = iter t 0
922+ where (c,d) = iter t 0
1277923 n = d + findAIndexOrEnd (not . p c) (Text arr (off+d) (len-d))
1278924
1279925-- | Returns the /array/ index (in units of 'Word16') at which a
@@ -1283,8 +929,8 @@ findAIndexOrEnd :: (Char -> Bool) -> Text -> Int
1283929findAIndexOrEnd q t@(Text _arr _off len) = go 0
1284930 where go !i | i >= len || q c = i
1285931 | otherwise = go (i+d)
1286− where Iter c d = iter t i
1287−
932+ where (c,d) = iter t i
933+
1288934-- | /O(n)/ Group characters in a string by equality.
1289935group :: Text -> [Text]
1290936group = groupBy (==)
@@ -1308,43 +954,36 @@ tails t | null t = [empty]
1308954-- copies to create substrings; they just construct new 'Text's that
1309955-- are slices of the original.
1310956
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.
957+-- | /O(m+n)/ Break a 'Text' into pieces separated by the first
958+-- 'Text' argument, consuming the delimiter. An empty delimiter is
959+-- invalid, and will cause an error to be raised.
1314960--
1315961-- Examples:
1316962--
1317−-- > splitOn "\r\n" "a\r\nb\r\nd\r\ne" == ["a","b","d","e"]
1318−-- > splitOn "aaa" "aaaXaaaXaaaXaaa" == ["","X","X","X",""]
1319−-- > splitOn "x" "x" == ["",""]
1320−--
963+-- > split "\r\n" "a\r\nb\r\nd\r\ne" == ["a","b","d","e"]
964+-- > split "aaa" "aaaXaaaXaaaXaaa" == ["","X","X","X",""]
965+-- > split "x" "x" == ["",""]
966+--
1321967-- and
1322968--
1323−-- > intercalate s . splitOn s == id
1324−-- > splitOn (singleton c) == split (==c)
1325−--
1326−-- (Note: the string @s@ to split on above cannot be empty.)
969+-- > intercalate s . split s == id
970+-- > split (singleton c) == splitBy (==c)
1327971--
1328972-- In (unlikely) bad cases, this function's time complexity degrades
1329973-- towards /O(n*m)/.
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]
1336−splitOn pat@(Text _ _ l) src@(Text arr off len)
1337− | l <= 0 = emptyError "splitOn"
1338− | isSingleton pat = split (== unsafeHead pat) src
974+split :: Text -> Text -> [Text]
975+split pat@(Text _ _ l) src@(Text arr off len)
976+ | l <= 0 = emptyError "split"
977+ | isSingleton pat = splitBy (== unsafeHead pat) src
1339978 | otherwise = go 0 (indices pat src)
1340979 where
1341− go !s (x:xs) = text arr (s+off) (x-s) : go (x+l) xs
1342− go s _ = [text arr (s+off) (len-s)]
1343−{-# INLINE [1] splitOn #-}
980+ go !s (x:xs) = textP arr (s+off) (x-s) : go (x+l) xs
981+ go s _ = [textP arr (s+off) (len-s)]
982+{-# INLINE [1] split #-}
1344983
1345984{-# RULES
1346−"TEXT splitOn/singleton -> split/==" [~1] forall c t.
1347− splitOn (singleton c) t = split (==c) t
985+"TEXT split/singleton -> splitBy/==" [~1] forall c t.
986+ split (singleton c) t = splitBy (==c) t
1348987 #-}
1349988
1350989-- | /O(n)/ Splits a 'Text' into components delimited by separators,
@@ -1352,15 +991,15 @@ splitOn pat@(Text _ _ l) src@(Text arr off len)
1352991-- resulting components do not contain the separators. Two adjacent
1353992-- separators result in an empty component in the output. eg.
1354993--
1355−-- > split (=='a') "aabbaca" == ["","","bb","c",""]
1356−-- > split (=='a') "" == [""]
1357−split :: (Char -> Bool) -> Text -> [Text]
1358−split _ t@(Text _off _arr 0) = [t]
1359−split p t = loop t
994+-- > splitBy (=='a') "aabbaca" == ["","","bb","c",""]
995+-- > splitBy (=='a') "" == [""]
996+splitBy :: (Char -> Bool) -> Text -> [Text]
997+splitBy _ t@(Text _off _arr 0) = [t]
998+splitBy p t = loop t
1360999 where loop s | null s' = [l]
13611000 | otherwise = l : loop (unsafeTail s')
1362− where (# l, s' #) = span_ (not . p) s
1363−{-# INLINE split #-}
1001+ where (l, s') = breakBy p s
1002+{-# INLINE splitBy #-}
13641003
13651004-- | /O(n)/ Splits a 'Text' into components of length @k@. The last
13661005-- element may be shorter than the other chunks, depending on the
@@ -1382,21 +1021,21 @@ chunksOf k = go
13821021-------------------------------------------------------------------------------
13831022-- ** Searching with a predicate
13841023
1385−-- | /O(n)/ The 'find' function takes a predicate and a 'Text', and
1386−-- returns the first element matching the predicate, or 'Nothing' if
1387−-- there is no such element.
1388−find :: (Char -> Bool) -> Text -> Maybe Char
1389−find p t = S.findBy p (stream t)
1390−{-# INLINE find #-}
1024+-- | /O(n)/ The 'findBy' function takes a predicate and a 'Text', and
1025+-- returns the first element in matching the predicate, or 'Nothing'
1026+-- if there is no such element.
1027+findBy :: (Char -> Bool) -> Text -> Maybe Char
1028+findBy p t = S.findBy p (stream t)
1029+{-# INLINE findBy #-}
13911030
1392−-- | /O(n)/ The 'partition' function takes a predicate and a 'Text',
1031+-- | /O(n)/ The 'partitionBy' function takes a predicate and a 'Text',
13931032-- and returns the pair of 'Text's with elements which do and do not
13941033-- satisfy the predicate, respectively; i.e.
13951034--
1396−-- > partition p t == (filter p t, filter (not . p) t)
1397−partition :: (Char -> Bool) -> Text -> (Text, Text)
1398−partition p t = (filter p t, filter (not . p) t)
1399−{-# INLINE partition #-}
1035+-- > partitionBy p t == (filter p t, filter (not . p) t)
1036+partitionBy :: (Char -> Bool) -> Text -> (Text, Text)
1037+partitionBy p t = (filter p t, filter (not . p) t)
1038+{-# INLINE partitionBy #-}
14001039
14011040-- | /O(n)/ 'filter', applied to a predicate and a 'Text',
14021041-- returns a 'Text' containing those characters that satisfy the
@@ -1412,69 +1051,71 @@ filter p t = unstream (S.filter p (stream t))
14121051--
14131052-- Examples:
14141053--
1415−-- > breakOn "::" "a::b::c" ==> ("a", "::b::c")
1416−-- > breakOn "/" "foobar" ==> ("foobar", "")
1054+-- > break "::" "a::b::c" ==> ("a", "::b::c")
1055+-- > break "/" "foobar" ==> ("foobar", "")
14171056--
14181057-- Laws:
14191058--
14201059-- > append prefix match == haystack
1421−-- > where (prefix, match) = breakOn needle haystack
1060+-- > where (prefix, match) = break needle haystack
14221061--
14231062-- If you need to break a string by a substring repeatedly (e.g. you
1424−-- want to break on every instance of a substring), use 'breakOnAll'
1063+-- want to break on every instance of a substring), use 'find'
14251064-- instead, as it has lower startup overhead.
14261065--
14271066-- In (unlikely) bad cases, this function's time complexity degrades
14281067-- towards /O(n*m)/.
1429−breakOn :: Text -> Text -> (Text, Text)
1430−breakOn pat src@(Text arr off len)
1431− | null pat = emptyError "breakOn"
1068+break :: Text -> Text -> (Text, Text)
1069+break pat src@(Text arr off len)
1070+ | null pat = emptyError "break"
14321071 | otherwise = case indices pat src of
14331072 [] -> (src, empty)
1434− (x:_) -> (text arr off x, text arr (off+x) (len-x))
1435−{-# INLINE breakOn #-}
1073+ (x:_) -> (textP arr off x, textP arr (off+x) (len-x))
1074+{-# INLINE break #-}
14361075
1437−-- | /O(n+m)/ Similar to 'breakOn', but searches from the end of the
1438−-- string.
1076+-- | /O(n+m)/ Similar to 'break', but searches from the end of the string.
14391077--
14401078-- The first element of the returned tuple is the prefix of @haystack@
14411079-- up to and including the last match of @needle@. The second is the
14421080-- remainder of @haystack@, following the match.
14431081--
1444−-- > breakOnEnd "::" "a::b::c" ==> ("a::b::", "c")
1445−breakOnEnd :: Text -> Text -> (Text, Text)
1446−breakOnEnd pat src = (reverse b, reverse a)
1447− where (a,b) = breakOn (reverse pat) (reverse src)
1448−{-# INLINE breakOnEnd #-}
1082+-- > breakEnd "::" "a::b::c" ==> ("a::b::", "c")
1083+breakEnd :: Text -> Text -> (Text, Text)
1084+breakEnd pat src = let (a,b) = break (reverse pat) (reverse src)
1085+ in (reverse b, reverse a)
1086+{-# INLINE breakEnd #-}
14491087
14501088-- | /O(n+m)/ Find all non-overlapping instances of @needle@ in
1451−-- @haystack@. Each element of the returned list consists of a pair:
1452−--
1453−-- * The entire string prior to the /k/th match (i.e. the prefix)
1089+-- @haystack@. The first element of the returned pair is the prefix
1090+-- of @haystack@ prior to any matches of @needle@. The second is a
1091+-- list of pairs.
14541092--
1455−-- * The /k/th match, followed by the remainder of the string
1093+-- The first element of each pair in the list is a span from the
1094+-- beginning of a match to the beginning of the next match, while the
1095+-- second is a span from the beginning of the match to the end of the
1096+-- input.
14561097--
14571098-- Examples:
14581099--
1459−-- > breakOnAll "::" ""
1460−-- > ==> []
1461−-- > breakOnAll "/" "a/b/c/"
1462−-- > ==> [("a", "/b/c/"), ("a/b", "/c/"), ("a/b/c", "/")]
1100+-- > find "::" ""
1101+-- > ==> ("", [])
1102+-- > find "/" "a/b/c/d"
1103+-- > ==> ("a", [("/b","/b/c/d"), ("/c","/c/d"), ("/d","/d")])
14631104--
14641105-- In (unlikely) bad cases, this function's time complexity degrades
14651106-- towards /O(n*m)/.
1466−--
1467−-- The @needle@ parameter may not be empty.
1468−breakOnAll :: Text -- ^ @needle@ to search for
1469− -> Text -- ^ @haystack@ in which to search
1470− -> [(Text, Text)]
1471−breakOnAll pat src@(Text arr off slen)
1472− | null pat = emptyError "breakOnAll"
1473− | otherwise = L.map step (indices pat src)
1107+find :: Text -> Text -> (Text, [(Text, Text)])
1108+find pat src@(Text arr off len)
1109+ | null pat = emptyError "find"
1110+ | otherwise = case indices pat src of
1111+ [] -> (src, [])
1112+ (x:xs) -> (chunk 0 x, go x xs)
14741113 where
1475− step x = (chunk 0 x, chunk x (slen-x))
1476− chunk !n !l = text arr (n+off) l
1477−{-# INLINE breakOnAll #-}
1114+ go !s (x:xs) = (chunk s (x-s), chunk s (len-s)) : go x xs
1115+ go s _ = let c = chunk s (len-s)
1116+ in [(c,c)]
1117+ chunk !n !l = textP arr (n+off) l
1118+{-# INLINE find #-}
14781119
14791120-------------------------------------------------------------------------------
14801121-- ** Indexing 'Text's
@@ -1493,7 +1134,7 @@ breakOnAll pat src@(Text arr off slen)
14931134-- For example, suppose you have a string that you want to split on
14941135-- the substring @\"::\"@, such as @\"foo::bar::quux\"@. Instead of
14951136-- searching for the index of @\"::\"@ and taking the substrings
1496−-- before and after that index, you would instead use @breakOnAll \"::\"@.
1137+-- before and after that index, you would instead use @find \"::\"@.
14971138
14981139-- | /O(n)/ 'Text' index (subscript) operator, starting from 0.
14991140index :: Text -> Int -> Char
@@ -1540,15 +1181,13 @@ countChar c t = S.countChar c (stream t)
15401181-- equivalent to a pair of 'unpack' operations.
15411182zip :: Text -> Text -> [(Char,Char)]
15421183zip a b = S.unstreamList $ S.zipWith (,) (stream a) (stream b)
1543−{-# INLINE zip #-}
1184+{-# INLINE [0] zip #-}
15441185
15451186-- | /O(n)/ 'zipWith' generalises 'zip' by zipping with the function
15461187-- given as the first argument, instead of a tupling function.
1547−-- Performs replacement on invalid scalar values.
15481188zipWith :: (Char -> Char -> Char) -> Text -> Text -> Text
1549−zipWith f t1 t2 = unstream (S.zipWith g (stream t1) (stream t2))
1550− where g a b = safe (f a b)
1551−{-# INLINE zipWith #-}
1189+zipWith f t1 t2 = unstream (S.zipWith f (stream t1) (stream t2))
1190+{-# INLINE [0] zipWith #-}
15521191
15531192-- | /O(n)/ Breaks a 'Text' up into a list of words, delimited by 'Char's
15541193-- representing white space.
@@ -1564,7 +1203,7 @@ words t@(Text arr off len) = loop 0 0
15641203 then loop (start+1) (start+1)
15651204 else Text arr (start+off) (n-start) : loop (n+d) (n+d)
15661205 | otherwise = loop start (n+d)
1567− where Iter c d = iter t n
1206+ where (c,d) = iter t n
15681207{-# INLINE words #-}
15691208
15701209-- | /O(n)/ Breaks a 'Text' up into a list of 'Text's at
@@ -1574,7 +1213,7 @@ lines ps | null ps = []
15741213 | otherwise = h : if null t
15751214 then []
15761215 else lines (unsafeTail t)
1577− where (# h,t #) = span_ (/= '\n') ps
1216+ where (h,t) = spanBy (/= '\n') ps
15781217{-# INLINE lines #-}
15791218
15801219{-
@@ -1611,7 +1250,8 @@ unwords = intercalate (singleton ' ')
16111250{-# INLINE unwords #-}
16121251
16131252-- | /O(n)/ The 'isPrefixOf' function takes two 'Text's and returns
1614−-- 'True' iff the first is a prefix of the second. Subject to fusion.
1253+-- 'True' iff the first is a prefix of the second. This function is
1254+-- subject to fusion.
16151255isPrefixOf :: Text -> Text -> Bool
16161256isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) =
16171257 alen <= blen && S.isPrefixOf (stream a) (stream b)
@@ -1620,6 +1260,8 @@ isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) =
16201260{-# RULES
16211261"TEXT isPrefixOf -> fused" [~1] forall s t.
16221262 isPrefixOf s t = S.isPrefixOf (stream s) (stream t)
1263+"TEXT isPrefixOf -> unfused" [1] forall s t.
1264+ S.isPrefixOf (stream s) (stream t) = isPrefixOf s t
16231265 #-}
16241266
16251267-- | /O(n)/ The 'isSuffixOf' function takes two 'Text's and returns
@@ -1650,106 +1292,5 @@ isInfixOf needle haystack
16501292 isInfixOf (singleton n) h = S.elem n (S.stream h)
16511293 #-}
16521294
1653−-------------------------------------------------------------------------------
1654−-- * View patterns
1655−
1656−-- | /O(n)/ Return the suffix of the second string if its prefix
1657−-- matches the entire first string.
1658−--
1659−-- Examples:
1660−--
1661−-- > stripPrefix "foo" "foobar" == Just "bar"
1662−-- > stripPrefix "" "baz" == Just "baz"
1663−-- > stripPrefix "foo" "quux" == Nothing
1664−--
1665−-- This is particularly useful with the @ViewPatterns@ extension to
1666−-- GHC, as follows:
1667−--
1668−-- > {-# LANGUAGE ViewPatterns #-}
1669−-- > import Data.Text as T
1670−-- >
1671−-- > fnordLength :: Text -> Int
1672−-- > fnordLength (stripPrefix "fnord" -> Just suf) = T.length suf
1673−-- > fnordLength _ = -1
1674−stripPrefix :: Text -> Text -> Maybe Text
1675−stripPrefix p@(Text _arr _off plen) t@(Text arr off len)
1676− | p `isPrefixOf` t = Just $! text arr (off+plen) (len-plen)
1677− | otherwise = Nothing
1678−
1679−-- | /O(n)/ Find the longest non-empty common prefix of two strings
1680−-- and return it, along with the suffixes of each string at which they
1681−-- no longer match.
1682−--
1683−-- If the strings do not have a common prefix or either one is empty,
1684−-- this function returns 'Nothing'.
1685−--
1686−-- Examples:
1687−--
1688−-- > commonPrefixes "foobar" "fooquux" == Just ("foo","bar","quux")
1689−-- > commonPrefixes "veeble" "fetzer" == Nothing
1690−-- > commonPrefixes "" "baz" == Nothing
1691−commonPrefixes :: Text -> Text -> Maybe (Text,Text,Text)
1692−commonPrefixes t0@(Text arr0 off0 len0) t1@(Text arr1 off1 len1) = go 0 0
1693− where
1694− go !i !j | i < len0 && j < len1 && a == b = go (i+d0) (j+d1)
1695− | i > 0 = Just (Text arr0 off0 i,
1696− text arr0 (off0+i) (len0-i),
1697− text arr1 (off1+j) (len1-j))
1698− | otherwise = Nothing
1699− where Iter a d0 = iter t0 i
1700− Iter b d1 = iter t1 j
1701−
1702−-- | /O(n)/ Return the prefix of the second string if its suffix
1703−-- matches the entire first string.
1704−--
1705−-- Examples:
1706−--
1707−-- > stripSuffix "bar" "foobar" == Just "foo"
1708−-- > stripSuffix "" "baz" == Just "baz"
1709−-- > stripSuffix "foo" "quux" == Nothing
1710−--
1711−-- This is particularly useful with the @ViewPatterns@ extension to
1712−-- GHC, as follows:
1713−--
1714−-- > {-# LANGUAGE ViewPatterns #-}
1715−-- > import Data.Text as T
1716−-- >
1717−-- > quuxLength :: Text -> Int
1718−-- > quuxLength (stripSuffix "quux" -> Just pre) = T.length pre
1719−-- > quuxLength _ = -1
1720−stripSuffix :: Text -> Text -> Maybe Text
1721−stripSuffix p@(Text _arr _off plen) t@(Text arr off len)
1722− | p `isSuffixOf` t = Just $! text arr off (len-plen)
1723− | otherwise = Nothing
1724−
1725−-- | Add a list of non-negative numbers. Errors out on overflow.
1726−sumP :: String -> [Int] -> Int
1727−sumP fun = go 0
1728− where go !a (x:xs)
1729− | ax >= 0 = go ax xs
1730− | otherwise = overflowError fun
1731− where ax = a + x
1732− go a _ = a
1733−
17341295emptyError :: String -> a
1735−emptyError fun = P.error $ "Data.Text." ++ fun ++ ": empty input"
1736−
1737−overflowError :: String -> a
1738−overflowError fun = P.error $ "Data.Text." ++ fun ++ ": size overflow"
1739−
1740−-- | /O(n)/ Make a distinct copy of the given string, sharing no
1741−-- storage with the original string.
1742−--
1743−-- As an example, suppose you read a large string, of which you need
1744−-- only a small portion. If you do not use 'copy', the entire original
1745−-- array will be kept alive in memory by the smaller string. Making a
1746−-- copy \"breaks the link\" to the original array, allowing it to be
1747−-- garbage collected if there are no other live references to it.
1748−copy :: Text -> Text
1749−copy (Text arr off len) = Text (A.run go) 0 len
1750− where
1751− go :: ST s (A.MArray s)
1752− go = do
1753− marr <- A.new len
1754− A.copyI marr 0 arr off len
1755− return marr
1296+emptyError fun = P.error ("Data.Text." ++ fun ++ ": empty input")