@@ -1,48 +1,29 @@
1−{-# LANGUAGE BangPatterns, CPP, MagicHash, Rank2Types, UnboxedTuples #-}
1+{-# LANGUAGE BangPatterns #-}
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, rtharper@aftereternity.co.uk,
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
@@ -74,19 +54,9 @@ module Data.Text
7454 , intersperse
7555 , transpose
7656 , reverse
77− , replace
7857
79− -- ** Case conversion
80− -- $case
81− , toCaseFold
82− , toLower
58+ -- * Case conversion
8359 , toUpper
84− , toTitle
85−
86− -- ** Justification
87− , justifyLeft
88− , justifyRight
89− , center
9060
9161 -- * Folds
9262 , foldl
@@ -125,32 +95,21 @@ module Data.Text
12595
12696 -- ** Breaking strings
12797 , take
128− , takeEnd
12998 , drop
130− , dropEnd
13199 , takeWhile
132− , takeWhileEnd
133100 , dropWhile
134− , dropWhileEnd
135− , dropAround
136− , strip
137− , stripStart
138− , stripEnd
139101 , splitAt
140− , breakOn
141− , breakOnEnd
142− , break
143102 , span
103+ , break
144104 , group
145105 , groupBy
146106 , inits
147107 , tails
148108
149109 -- ** Breaking into many substrings
150− -- $split
151− , splitOn
152110 , split
153− , chunksOf
111+ , splitWith
112+ , breakSubstring
154113
155114 -- ** Breaking into lines and words
156115 , lines
@@ -164,309 +123,137 @@ module Data.Text
164123 , isSuffixOf
165124 , isInfixOf
166125
167− -- ** View patterns
168− , stripPrefix
169− , stripSuffix
170− , commonPrefixes
171−
172126 -- * Searching
127+ , elem
173128 , filter
174− , breakOnAll
175129 , find
176130 , partition
177131
178132 -- , findSubstring
179−
133+
180134 -- * Indexing
181− -- $index
182135 , index
183136 , findIndex
137+ , findIndices
138+ , elemIndex
139+ , elemIndices
184140 , count
185141
186− -- * Zipping
142+ -- * Zipping and unzipping
187143 , zip
188144 , zipWith
189145
190146 -- -* Ordered text
191147 -- , sort
192−
193− -- * Low level operations
194− , copy
195− , unpackCString#
196148 ) where
197149
198−import Prelude (Char, Bool(..), Int, Maybe(..), String,
199− Eq(..), Ord(..), Ordering(..), (++),
200− Read(..),
201− (&&), (||), (+), (-), (.), ($), ($!), (>>),
202− not, return, otherwise, quot)
203−#if defined(HAVE_DEEPSEQ)
204−import Control.DeepSeq (NFData(rnf))
205−#endif
206−#if defined(ASSERTS)
150+import Prelude (Char, Bool(..), Functor(..), Int, Maybe(..), String,
151+ Eq(..), Ord(..), (++),
152+ Read(..), Show(..),
153+ (&&), (||), (+), (-), (.), ($),
154+ not, return, otherwise)
207155import Control.Exception (assert)
208−#endif
209156import Data.Char (isSpace)
210−import Data.Data (Data(gfoldl, toConstr, gunfold, dataTypeOf), constrIndex,
211− Constr, mkConstr, DataType, mkDataType, Fixity(Prefix))
212−import Control.Monad (foldM)
213157import Control.Monad.ST (ST)
214158import qualified Data.Text.Array as A
215159import qualified Data.List as L
216−import Data.Binary (Binary(get, put))
217160import Data.Monoid (Monoid(..))
218−#if MIN_VERSION_base(4,9,0)
219−import Data.Semigroup (Semigroup(..))
220−#endif
161+import Data.Word (Word16)
221162import 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#)
229−import 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.
269163
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 >.)
164+import qualified Data.Text.Fusion as S
165+import qualified Data.Text.Fusion.Common as S
166+import Data.Text.Fusion (stream, reverseStream, unstream)
167+
168+import Data.Text.Internal (Text(..), empty, text, textP)
169+import qualified Prelude as P
170+import Data.Text.Unsafe (iter, iter_, unsafeHead, unsafeTail)
171+import Data.Text.UnsafeChar (unsafeChr)
172+import qualified Data.Text.Encoding.Utf16 as U16
298173
299174-- $fusion
300175--
301−-- Most of the functions in this module are subject to /fusion/,
302−-- meaning that a pipeline of such functions will usually allocate at
303−-- 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\".
176+-- Most of the functions in this module are subject to /array fusion/,
177+-- meaning that a pipeline of functions will usually allocate at most
178+-- one 'Text' value.
323179
324180instance 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
181+ t1 == t2 = stream t1 == stream t2
328182 {-# INLINE (==) #-}
329183
330184instance Ord Text where
331− compare = compareText
185+ compare t1 t2 = compare (stream t1) (stream t2)
186+ {-# INLINE compare #-}
187+
188+instance Show Text where
189+ showsPrec p ps r = showsPrec p (unpack ps) r
332190
333191instance Read Text where
334192 readsPrec p str = [(pack x,y) | (x,y) <- readsPrec p str]
335193
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−
344194instance Monoid Text where
345195 mempty = empty
346−#if MIN_VERSION_base(4,9,0)
347− mappend = (<>) -- future-proof definition
348−#else
349196 mappend = append
350−#endif
351197 mconcat = concat
352198
353199instance IsString Text where
354200 fromString = pack
355201
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−
363−#if defined(HAVE_DEEPSEQ)
364−instance NFData Text where rnf !_ = ()
365−#endif
366−
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.
376−-- We omit reflection services for the sake of data abstraction.
377−--
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, ... >
389−
390−instance Data Text where
391− 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
402−#endif
403−
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−
424202-- -----------------------------------------------------------------------------
425203-- * Conversion to/from 'Text'
426204
427−-- | /O(n)/ Convert a 'String' into a 'Text'. Subject to
428−-- fusion. Performs replacement on invalid scalar values.
205+-- | /O(n)/ Convert a 'String' into a 'Text'.
206+--
207+-- This function is subject to array fusion.
429208pack :: String -> Text
430−pack = unstream . S.map safe . S.streamList
209+pack = unstream . S.streamList
431210{-# INLINE [1] pack #-}
432211
212+-- | /O(n)/ Convert a Text into a String.
213+-- Subject to array fusion.
214+unpack :: Text -> String
215+unpack = S.unstreamList . stream
216+{-# INLINE [1] unpack #-}
217+
218+-- | /O(1)/ Convert a character into a Text.
219+-- Subject to array fusion.
220+singleton :: Char -> Text
221+singleton = unstream . S.singleton
222+{-# INLINE [1] singleton #-}
223+
433224-- -----------------------------------------------------------------------------
434225-- * Basic functions
435226
436227-- | /O(n)/ Adds a character to the front of a 'Text'. This function
437228-- 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.
229+-- copying a new array. Subject to array fusion.
440230cons :: Char -> Text -> Text
441−cons c t = unstream (S.cons (safe c) (stream t))
231+cons c t = unstream (S.cons c (stream t))
442232{-# INLINE cons #-}
443233
444−infixr 5 `cons`
445−
446234-- | /O(n)/ Adds a character to the end of a 'Text'. This copies the
447−-- entire array in the process, unless fused. Subject to fusion.
448−-- Performs replacement on invalid scalar values.
235+-- entire array in the process. Subject to array fusion.
449236snoc :: Text -> Char -> Text
450−snoc t c = unstream (S.snoc (stream t) (safe c))
237+snoc t c = unstream (S.snoc (stream t) c)
451238{-# INLINE snoc #-}
452239
453240-- | /O(n)/ Appends one 'Text' to the other by copying both of them
454−-- into a new 'Text'. Subject to fusion.
241+-- into a new 'Text'. Subject to array fusion.
455242append :: 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"
243+append (Text arr1 off1 len1) (Text arr2 off2 len2) = Text (A.run x) 0 len
461244 where
462245 len = len1+len2
463− x :: ST s (A.MArray s)
464246 x = do
465− arr <- A.new len
466− A.copyI arr 0 arr1 off1 len1
467− A.copyI arr len1 arr2 off2 len
247+ arr <- A.unsafeNew len :: ST s (A.MArray s Word16)
248+ copy arr1 off1 (len1+off1) arr 0
249+ copy arr2 off2 (len2+off2) arr len1
468250 return arr
469−{-# NOINLINE append #-}
251+ where
252+ copy arr i top arr' j
253+ | i >= top = return ()
254+ | otherwise = do A.unsafeWrite arr' j (arr `A.unsafeIndex` i)
255+ copy arr (i+1) top arr' (j+1)
256+{-# INLINE append #-}
470257
471258{-# RULES
472259"TEXT append -> fused" [~1] forall t1 t2.
@@ -476,26 +263,33 @@ append a@(Text arr1 off1 len1) b@(Text arr2 off2 len2)
476263 #-}
477264
478265-- | /O(1)/ Returns the first character of a 'Text', which must be
479−-- non-empty. Subject to fusion.
266+-- non-empty. Subject to array fusion.
480267head :: Text -> Char
481268head t = S.head (stream t)
482269{-# INLINE head #-}
483270
484271-- | /O(1)/ Returns the first character and rest of a 'Text', or
485−-- 'Nothing' if empty. Subject to fusion.
272+-- 'Nothing' if empty. Subject to array fusion.
486273uncons :: Text -> Maybe (Char, Text)
487274uncons t@(Text arr off len)
488275 | len <= 0 = Nothing
489− | otherwise = Just $ let !(Iter c d) = iter t 0
490− in (c, text arr (off+d) (len-d))
491−{-# INLINE [1] uncons #-}
276+ | otherwise = Just (c, textP arr (off+d) (len-d))
277+ where (c,d) = iter t 0
278+{-# INLINE uncons #-}
492279
493280-- | Lifted from Control.Arrow and specialized.
494281second :: (b -> c) -> (a,b) -> (a,c)
495282second f (a, b) = (a, f b)
496283
284+{-# RULES
285+"TEXT uncons -> fused" [~1] forall t.
286+ uncons t = fmap (second unstream) (S.uncons (stream t))
287+"TEXT uncons -> unfused" [1] forall t.
288+ fmap (second unstream) (S.uncons (stream t)) = uncons t
289+ #-}
290+
497291-- | /O(1)/ Returns the last character of a 'Text', which must be
498−-- non-empty. Subject to fusion.
292+-- non-empty. Subject to array fusion.
499293last :: Text -> Char
500294last (Text arr off len)
501295 | len <= 0 = emptyError "last"
@@ -513,11 +307,11 @@ last (Text arr off len)
513307 #-}
514308
515309-- | /O(1)/ Returns all characters after the head of a 'Text', which
516−-- must be non-empty. Subject to fusion.
310+-- must be non-empty. Subject to array fusion.
517311tail :: Text -> Text
518312tail t@(Text arr off len)
519313 | len <= 0 = emptyError "tail"
520− | otherwise = text arr (off+d) (len-d)
314+ | otherwise = textP arr (off+d) (len-d)
521315 where d = iter_ t 0
522316{-# INLINE [1] tail #-}
523317
@@ -529,11 +323,11 @@ tail t@(Text arr off len)
529323 #-}
530324
531325-- | /O(1)/ Returns all but the last character of a 'Text', which must
532−-- be non-empty. Subject to fusion.
326+-- be non-empty. Subject to array fusion.
533327init :: Text -> Text
534328init (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)
329+ | n >= 0xDC00 && n <= 0xDFFF = textP arr off (len-2)
330+ | otherwise = textP arr off (len-1)
537331 where
538332 n = A.unsafeIndex arr (off+len-1)
539333{-# INLINE [1] init #-}
@@ -545,14 +339,10 @@ init (Text arr off len) | len <= 0 = emptyError "init"
545339 unstream (S.init (stream t)) = init t
546340 #-}
547341
548−-- | /O(1)/ Tests whether a 'Text' is empty or not. Subject to
342+-- | /O(1)/ Tests whether a 'Text' is empty or not. Subject to array
549343-- fusion.
550344null :: Text -> Bool
551−null (Text _arr _off len) =
552−#if defined(ASSERTS)
553− assert (len >= 0) $
554−#endif
555− len <= 0
345+null (Text _arr _off len) = assert (len >= 0) $ len <= 0
556346{-# INLINE [1] null #-}
557347
558348{-# RULES
@@ -562,284 +352,46 @@ null (Text _arr _off len) =
562352 S.null (stream t) = null t
563353 #-}
564354
565−-- | /O(1)/ Tests whether a 'Text' contains exactly one character.
566−-- Subject to fusion.
567−isSingleton :: Text -> Bool
568−isSingleton = S.isSingleton . stream
569−{-# INLINE isSingleton #-}
570−
571355-- | /O(n)/ Returns the number of characters in a 'Text'.
572−-- Subject to fusion.
356+-- Subject to array fusion.
573357length :: Text -> Int
574358length 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− #-}
359+{-# INLINE length #-}
623360
624361-- -----------------------------------------------------------------------------
625362-- * Transformations
626−-- | /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.
363+-- | /O(n)/ 'map' @f @xs is the 'Text' obtained by applying @f@ to
364+-- each element of @xs@. Subject to array fusion.
629365map :: (Char -> Char) -> Text -> Text
630−map f t = unstream (S.map (safe . f) (stream t))
366+map f t = unstream (S.map f (stream t))
631367{-# INLINE [1] map #-}
632368
633369-- | /O(n)/ The 'intercalate' function takes a 'Text' and a list of
634370-- 'Text's and concatenates the list after interspersing the first
635371-- argument between each element of the list.
636372intercalate :: Text -> [Text] -> Text
637−intercalate t = concat . (F.intersperse t)
373+intercalate t ts = unstream (S.intercalate (stream t) (L.map stream ts))
638374{-# INLINE intercalate #-}
639375
640376-- | /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.
377+-- between the characters of a 'Text'. Subject to array fusion.
643378intersperse :: Char -> Text -> Text
644−intersperse c t = unstream (S.intersperse (safe c) (stream t))
379+intersperse c t = unstream (S.intersperse c (stream t))
645380{-# INLINE intersperse #-}
646381
647−-- | /O(n)/ Reverse the characters of a string. Subject to fusion.
382+-- | /O(n)/ Reverse the characters of a string. Subject to array fusion.
648383reverse :: Text -> Text
649384reverse t = S.reverse (stream t)
650385{-# INLINE reverse #-}
651386
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.
682− -> 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
705−
706−-- ----------------------------------------------------------------------------
707−-- ** Case conversions (folds)
708−
709−-- $case
710−--
711−-- When case converting 'Text' values, do not use combinators like
712−-- @map toUpper@ to case convert each character of a string
713−-- individually, as this gives incorrect results according to the
714−-- rules of some writing systems. The whole-string case conversion
715−-- functions from this module, such as @toUpper@, obey the correct
716−-- case conversion rules. As a result, these functions may map one
717−-- input character to two or three output characters. For examples,
718−-- 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 >.
725−
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.
730−--
731−-- A string @x@ is a caseless match for a string @y@ if and only if:
732−--
733−-- @toCaseFold x == toCaseFold y@
734−--
735−-- The result string may be longer than the input string, and may
736−-- differ from applying 'toLower' to the input string. For instance,
737−-- the Armenian small ligature \"ﬓ\" (men now, U+FB13) is case
738−-- folded to the sequence \"մ\" (men, U+0574) followed by
739−-- \"ն\" (now, U+0576), while the Greek \"µ\" (micro sign,
740−-- U+00B5) is case folded to \"μ\" (small letter mu, U+03BC)
741−-- instead of itself.
742−toCaseFold :: Text -> Text
743−toCaseFold t = unstream (S.toCaseFold (stream t))
744−{-# INLINE toCaseFold #-}
745−
746−-- | /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).
753−toLower :: Text -> Text
754−toLower t = unstream (S.toLower (stream t))
755−{-# INLINE toLower #-}
756−
757387-- | /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
762−-- two-letter sequence \"SS\".
388+-- conversion. The result string may be longer than the input string.
389+-- For instance, the German eszett (U+00DF) maps to the two-letter
390+-- sequence SS.
763391toUpper :: Text -> Text
764392toUpper t = unstream (S.toUpper (stream t))
765393{-# INLINE toUpper #-}
766394
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−
789−-- | /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:
794−--
795−-- > justifyLeft 7 'x' "foo" == "fooxxxx"
796−-- > justifyLeft 3 'x' "foobar" == "foobar"
797−justifyLeft :: Int -> Char -> Text -> Text
798−justifyLeft k c t
799− | len >= k = t
800− | otherwise = t `append` replicateChar (k-len) c
801− where len = length t
802−{-# INLINE [1] justifyLeft #-}
803−
804−{-# RULES
805−"TEXT justifyLeft -> fused" [~1] forall k c t.
806− justifyLeft k c t = unstream (S.justifyLeftI k c (stream t))
807−"TEXT justifyLeft -> unfused" [1] forall k c t.
808− unstream (S.justifyLeftI k c (stream t)) = justifyLeft k c t
809− #-}
810−
811−-- | /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:
816−--
817−-- > justifyRight 7 'x' "bar" == "xxxxbar"
818−-- > justifyRight 3 'x' "foobar" == "foobar"
819−justifyRight :: Int -> Char -> Text -> Text
820−justifyRight k c t
821− | len >= k = t
822− | otherwise = replicateChar (k-len) c `append` t
823− where len = length t
824−{-# INLINE justifyRight #-}
825−
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:
831−--
832−-- > center 8 'x' "HS" = "xxxHSxxx"
833−center :: Int -> Char -> Text -> Text
834−center k c t
835− | len >= k = t
836− | otherwise = replicateChar l c `append` t `append` replicateChar r c
837− where len = length t
838− d = k - len
839− r = d `quot` 2
840− l = d - r
841−{-# INLINE center #-}
842−
843395-- | /O(n)/ The 'transpose' function transposes the rows and columns
844396-- of its 'Text' argument. Note that this function uses 'pack',
845397-- 'unpack', and the list version of transpose, and is thus not very
@@ -853,23 +405,26 @@ transpose ts = P.map pack (L.transpose (P.map unpack ts))
853405-- | /O(n)/ 'foldl', applied to a binary operator, a starting value
854406-- (typically the left-identity of the operator), and a 'Text',
855407-- reduces the 'Text' using the binary operator, from left to right.
856−-- Subject to fusion.
857−foldl :: (a -> Char -> a) -> a -> Text -> a
408+-- Subject to array fusion.
409+foldl :: (b -> Char -> b) -> b -> Text -> b
858410foldl f z t = S.foldl f z (stream t)
859411{-# INLINE foldl #-}
860412
861−-- | /O(n)/ A strict version of 'foldl'. Subject to fusion.
862−foldl' :: (a -> Char -> a) -> a -> Text -> a
413+-- | /O(n)/ A strict version of 'foldl'.
414+-- Subject to array fusion.
415+foldl' :: (b -> Char -> b) -> b -> Text -> b
863416foldl' f z t = S.foldl' f z (stream t)
864417{-# INLINE foldl' #-}
865418
866419-- | /O(n)/ A variant of 'foldl' that has no starting value argument,
867−-- and thus must be applied to a non-empty 'Text'. Subject to fusion.
420+-- and thus must be applied to a non-empty 'Text'. Subject to array
421+-- fusion.
868422foldl1 :: (Char -> Char -> Char) -> Text -> Char
869423foldl1 f t = S.foldl1 f (stream t)
870424{-# INLINE foldl1 #-}
871425
872−-- | /O(n)/ A strict version of 'foldl1'. Subject to fusion.
426+-- | /O(n)/ A strict version of 'foldl1'.
427+-- Subject to array fusion.
873428foldl1' :: (Char -> Char -> Char) -> Text -> Char
874429foldl1' f t = S.foldl1' f (stream t)
875430{-# INLINE foldl1' #-}
@@ -877,13 +432,13 @@ foldl1' f t = S.foldl1' f (stream t)
877432-- | /O(n)/ 'foldr', applied to a binary operator, a starting value
878433-- (typically the right-identity of the operator), and a 'Text',
879434-- reduces the 'Text' using the binary operator, from right to left.
880−-- Subject to fusion.
881−foldr :: (Char -> a -> a) -> a -> Text -> a
435+-- Subject to array fusion.
436+foldr :: (Char -> b -> b) -> b -> Text -> b
882437foldr f z t = S.foldr f z (stream t)
883438{-# INLINE foldr #-}
884439
885−-- | /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
440+-- | /O(n)/ A variant of 'foldr' that has no starting value argument, and
441+-- thust must be applied to a non-empty 'Text'. Subject to array
887442-- fusion.
888443foldr1 :: (Char -> Char -> Char) -> Text -> Char
889444foldr1 f t = S.foldr1 f (stream t)
@@ -892,48 +447,40 @@ foldr1 f t = S.foldr1 f (stream t)
892447-- -----------------------------------------------------------------------------
893448-- ** Special folds
894449
895−-- | /O(n)/ Concatenate a list of 'Text's.
450+-- | /O(n)/ Concatenate a list of 'Text's. Subject to array fusion.
896451concat :: [Text] -> Text
897−concat ts = case ts' of
898− [] -> empty
899− [t] -> t
900− _ -> Text (A.run go) 0 len
901− where
902− ts' = L.filter (not . null) ts
903− len = sumP "concat" $ L.map lengthWord16 ts'
904− go :: ST s (A.MArray s)
905− 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
452+concat ts = unstream (S.concat (L.map stream ts))
453+{-# INLINE concat #-}
910454
911455-- | /O(n)/ Map a function over a 'Text' that results in a 'Text', and
912−-- concatenate the results.
456+-- concatenate the results. This function is subject to array fusion.
457+--
458+-- Note: if in 'concatMap' @f@ @t@, @f@ is defined in terms of fusible
459+-- functions, it will also be fusible.
913460concatMap :: (Char -> Text) -> Text -> Text
914−concatMap f = concat . foldr ((:) . f) []
461+concatMap f t = unstream (S.concatMap (stream . f) (stream t))
915462{-# INLINE concatMap #-}
916463
917464-- | /O(n)/ 'any' @p@ @t@ determines whether any character in the
918−-- 'Text' @t@ satisfies the predicate @p@. Subject to fusion.
465+-- 'Text' @t@ satisifes the predicate @p@. Subject to array fusion.
919466any :: (Char -> Bool) -> Text -> Bool
920467any p t = S.any p (stream t)
921468{-# INLINE any #-}
922469
923470-- | /O(n)/ 'all' @p@ @t@ determines whether all characters in the
924−-- 'Text' @t@ satisfy the predicate @p@. Subject to fusion.
471+-- 'Text' @t@ satisify the predicate @p@. Subject to array fusion.
925472all :: (Char -> Bool) -> Text -> Bool
926473all p t = S.all p (stream t)
927474{-# INLINE all #-}
928475
929476-- | /O(n)/ 'maximum' returns the maximum value from a 'Text', which
930−-- must be non-empty. Subject to fusion.
477+-- must be non-empty. Subject to array fusion.
931478maximum :: Text -> Char
932479maximum t = S.maximum (stream t)
933480{-# INLINE maximum #-}
934481
935482-- | /O(n)/ 'minimum' returns the minimum value from a 'Text', which
936−-- must be non-empty. Subject to fusion.
483+-- must be non-empty. Subject to array fusion.
937484minimum :: Text -> Char
938485minimum t = S.minimum (stream t)
939486{-# INLINE minimum #-}
@@ -942,8 +489,8 @@ minimum t = S.minimum (stream t)
942489-- * Building 'Text's
943490
944491-- | /O(n)/ 'scanl' is similar to 'foldl', but returns a list of
945−-- successive reduced values from the left. Subject to fusion.
946−-- Performs replacement on invalid scalar values.
492+-- successive reduced values from the left. This function is subject
493+-- to array fusion.
947494--
948495-- > scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]
949496--
@@ -951,13 +498,11 @@ minimum t = S.minimum (stream t)
951498--
952499-- > last (scanl f z xs) == foldl f z xs.
953500scanl :: (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)
501+scanl f z t = unstream (S.scanl f z (stream t))
956502{-# INLINE scanl #-}
957503
958504-- | /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.
505+-- value argument. This function is subject to array fusion.
961506--
962507-- > scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]
963508scanl1 :: (Char -> Char -> Char) -> Text -> Text
@@ -965,75 +510,49 @@ scanl1 f t | null t = empty
965510 | otherwise = scanl f (unsafeHead t) (unsafeTail t)
966511{-# INLINE scanl1 #-}
967512
968−-- | /O(n)/ 'scanr' is the right-to-left dual of 'scanl'. Performs
969−-- replacement on invalid scalar values.
513+-- | /O(n)/ 'scanr' is the right-to-left dual of 'scanl'.
970514--
971515-- > scanr f v == reverse . scanl (flip f) v . reverse
972516scanr :: (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)
517+scanr f z = S.reverse . S.reverseScanr f z . reverseStream
975518{-# INLINE scanr #-}
976519
977520-- | /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.
521+-- value argument. This function is subject to array fusion.
980522scanr1 :: (Char -> Char -> Char) -> Text -> Text
981523scanr1 f t | null t = empty
982524 | otherwise = scanr f (last t) (init t)
983525{-# INLINE scanr1 #-}
984526
985−-- | /O(n)/ Like a combination of 'map' and 'foldl''. Applies a
527+-- | /O(n)/ Like a combination of 'map' and 'foldl'. Applies a
986528-- 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.
529+-- parameter from left to right, and returns a final 'Text'.
989530mapAccumL :: (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 #-}
531+mapAccumL f s t = case uncons t of
532+ Nothing -> (s, empty)
533+ Just (x, xs) -> (s'', cons y ys)
534+ where (s', y ) = f s x
535+ (s'',ys) = mapAccumL f s' xs
993536
994537-- | 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.
538+-- 'foldr'; it applies a function to each element of a 'Text', passing
539+-- an accumulating parameter from right to left, and returning a final
540+-- value of this accumulator together with the new 'Text'.
1000541mapAccumR :: (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 #-}
542+mapAccumR f s t = case uncons t of
543+ Nothing -> (s, empty)
544+ Just (x, xs) -> (s'', cons y ys)
545+ where (s'',y ) = f s' x
546+ (s', ys) = mapAccumR f s xs
1004547
1005548-- -----------------------------------------------------------------------------
1006549-- ** Generating and unfolding 'Text's
1007550
1008−-- | /O(n*m)/ 'replicate' @n@ @t@ is a 'Text' consisting of the input
1009−-- @t@ repeated @n@ times.
1010−replicate :: Int -> Text -> Text
1011−replicate 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
1016− where
1017− len = l `mul` n
1018− x :: ST s (A.MArray s)
1019− x = do
1020− arr <- A.new len
1021− let loop !d !i | i >= n = return arr
1022− | otherwise = let m = d + l
1023− in A.copyI arr d a o m >> loop m (i+1)
1024− loop 0 0
1025−{-# INLINE [1] replicate #-}
1026−
1027−{-# RULES
1028−"TEXT replicate/singleton -> replicateChar" [~1] forall n c.
1029− replicate n (singleton c) = replicateChar n c
1030− #-}
1031−
1032−-- | /O(n)/ 'replicateChar' @n@ @c@ is a 'Text' of length @n@ with @c@ the
551+-- | /O(n)/ 'replicate' @n@ @c@ is a 'Text' of length @n@ with @c@ the
1033552-- value of every element. Subject to fusion.
1034−replicateChar :: Int -> Char -> Text
1035−replicateChar n c = unstream (S.replicateCharI n (safe c))
1036−{-# INLINE replicateChar #-}
553+replicate :: Int -> Char -> Text
554+replicate n c = unstream (S.replicate n c)
555+{-# INLINE replicate #-}
1037556
1038557-- | /O(n)/, where @n@ is the length of the result. The 'unfoldr'
1039558-- function is analogous to the List 'L.unfoldr'. 'unfoldr' builds a
@@ -1041,9 +560,9 @@ replicateChar n c = unstream (S.replicateCharI n (safe c))
1041560-- returns 'Nothing' if it is done producing the 'Text', otherwise
1042561-- 'Just' @(a,b)@. In this case, @a@ is the next 'Char' in the
1043562-- string, and @b@ is the seed value for further production. Subject
1044−-- to fusion. Performs replacement on invalid scalar values.
563+-- to fusion.
1045564unfoldr :: (a -> Maybe (Char,a)) -> a -> Text
1046−unfoldr f s = unstream (S.unfoldr (firstf safe . f) s)
565+unfoldr f s = unstream (S.unfoldr f s)
1047566{-# INLINE unfoldr #-}
1048567
1049568-- | /O(n)/ Like 'unfoldr', 'unfoldrN' builds a 'Text' from a seed
@@ -1051,9 +570,9 @@ unfoldr f s = unstream (S.unfoldr (firstf safe . f) s)
1051570-- first argument to 'unfoldrN'. This function is more efficient than
1052571-- 'unfoldr' when the maximum length of the result is known and
1053572-- correct, otherwise its performance is similar to 'unfoldr'. Subject
1054−-- to fusion. Performs replacement on invalid scalar values.
573+-- to fusion.
1055574unfoldrN :: Int -> (a -> Maybe (Char,a)) -> a -> Text
1056−unfoldrN n f s = unstream (S.unfoldrN n (firstf safe . f) s)
575+unfoldrN n f s = unstream (S.unfoldrN n f s)
1057576{-# INLINE unfoldrN #-}
1058577
1059578-- -----------------------------------------------------------------------------
@@ -1066,16 +585,14 @@ take :: Int -> Text -> Text
1066585take n t@(Text arr off len)
1067586 | n <= 0 = empty
1068587 | n >= len = t
1069− | otherwise = text arr off (iterN n t)
588+ | otherwise = Text arr off (loop 0 0)
589+ where
590+ loop !i !cnt
591+ | i >= len || cnt >= n = i
592+ | otherwise = loop (i+d) (cnt+1)
593+ where d = iter_ t i
1070594{-# INLINE [1] take #-}
1071595
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−
1079596{-# RULES
1080597"TEXT take -> fused" [~1] forall n t.
1081598 take n t = unstream (S.take n (stream t))
@@ -1083,36 +600,18 @@ iterN n t@(Text _arr _off len) = loop 0 0
1083600 unstream (S.take n (stream t)) = take n t
1084601 #-}
1085602
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−
1107603-- | /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.
604+-- 'Text' of length @n@, or the empty 'Text' if @n@ is greater than the
605+-- length of the 'Text'. Subject to fusion.
1110606drop :: Int -> Text -> Text
1111607drop n t@(Text arr off len)
1112608 | n <= 0 = t
1113609 | n >= len = empty
1114− | otherwise = text arr (off+i) (len-i)
1115− where i = iterN n t
610+ | otherwise = loop 0 0
611+ where loop !i !cnt
612+ | i >= len || cnt >= n = Text arr (off+i) (len-i)
613+ | otherwise = loop (i+d) (cnt+1)
614+ where d = iter_ t i
1116615{-# INLINE [1] drop #-}
1117616
1118617{-# RULES
@@ -1122,27 +621,15 @@ drop n t@(Text arr off len)
1122621 unstream (S.drop n (stream t)) = drop n t
1123622 #-}
1124623
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−
1137−-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text',
1138−-- returns the longest prefix (possibly empty) of elements that
1139−-- satisfy @p@. Subject to fusion.
624+-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text', returns
625+-- the longest prefix (possibly empty) of elements that satisfy @p@.
626+-- This function is subject to array fusion.
1140627takeWhile :: (Char -> Bool) -> Text -> Text
1141628takeWhile p t@(Text arr off len) = loop 0
1142629 where loop !i | i >= len = t
1143630 | p c = loop (i+d)
1144− | otherwise = text arr off i
1145− where Iter c d = iter t i
631+ | otherwise = textP arr off i
632+ where (c,d) = iter t i
1146633{-# INLINE [1] takeWhile #-}
1147634
1148635{-# RULES
@@ -1152,35 +639,14 @@ takeWhile p t@(Text arr off len) = loop 0
1152639 unstream (S.takeWhile p (stream t)) = takeWhile p t
1153640 #-}
1154641
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−
1176−-- | /O(n)/ 'dropWhile' @p@ @t@ returns the suffix remaining after
1177−-- 'takeWhile' @p@ @t@. Subject to fusion.
642+-- | /O(n)/ 'dropWhile' @p@ @xs@ returns the suffix remaining after
643+-- 'takeWhile' @p@ @xs@. This function is subject to array fusion.
1178644dropWhile :: (Char -> Bool) -> Text -> Text
1179645dropWhile p t@(Text arr off len) = loop 0 0
1180646 where loop !i !l | l >= len = empty
1181647 | p c = loop (i+d) (l+d)
1182648 | otherwise = Text arr (off+i) (len-l)
1183− where Iter c d = iter t i
649+ where (c,d) = iter t i
1184650{-# INLINE [1] dropWhile #-}
1185651
1186652{-# RULES
@@ -1190,57 +656,6 @@ dropWhile p t@(Text arr off len) = loop 0 0
1190656 unstream (S.dropWhile p (stream t)) = dropWhile p t
1191657 #-}
1192658
1193−-- | /O(n)/ 'dropWhileEnd' @p@ @t@ returns the prefix remaining after
1194−-- dropping characters that satisfy the predicate @p@ from the end of
1195−-- @t@. Subject to fusion.
1196−--
1197−-- Examples:
1198−--
1199−-- > dropWhileEnd (=='.') "foo..." == "foo"
1200−dropWhileEnd :: (Char -> Bool) -> Text -> Text
1201−dropWhileEnd p t@(Text arr off len) = loop (len-1) len
1202− where loop !i !l | l <= 0 = empty
1203− | p c = loop (i+d) (l+d)
1204− | otherwise = Text arr off l
1205− where (c,d) = reverseIter t i
1206−{-# INLINE [1] dropWhileEnd #-}
1207−
1208−{-# RULES
1209−"TEXT dropWhileEnd -> fused" [~1] forall p t.
1210− dropWhileEnd p t = S.reverse (S.dropWhile p (S.reverseStream t))
1211−"TEXT dropWhileEnd -> unfused" [1] forall p t.
1212− S.reverse (S.dropWhile p (S.reverseStream t)) = dropWhileEnd p t
1213− #-}
1214−
1215−-- | /O(n)/ 'dropAround' @p@ @t@ returns the substring remaining after
1216−-- dropping characters that satisfy the predicate @p@ from both the
1217−-- beginning and end of @t@. Subject to fusion.
1218−dropAround :: (Char -> Bool) -> Text -> Text
1219−dropAround p = dropWhile p . dropWhileEnd p
1220−{-# INLINE [1] dropAround #-}
1221−
1222−-- | /O(n)/ Remove leading white space from a string. Equivalent to:
1223−--
1224−-- > dropWhile isSpace
1225−stripStart :: Text -> Text
1226−stripStart = dropWhile isSpace
1227−{-# INLINE [1] stripStart #-}
1228−
1229−-- | /O(n)/ Remove trailing white space from a string. Equivalent to:
1230−--
1231−-- > dropWhileEnd isSpace
1232−stripEnd :: Text -> Text
1233−stripEnd = dropWhileEnd isSpace
1234−{-# INLINE [1] stripEnd #-}
1235−
1236−-- | /O(n)/ Remove leading and trailing white space from a string.
1237−-- Equivalent to:
1238−--
1239−-- > dropAround isSpace
1240−strip :: Text -> Text
1241−strip = dropAround isSpace
1242−{-# INLINE [1] strip #-}
1243−
1244659-- | /O(n)/ 'splitAt' @n t@ returns a pair whose first element is a
1245660-- prefix of @t@ of length @n@, and whose second is the remainder of
1246661-- the string. It is equivalent to @('take' n t, 'drop' n t)@.
@@ -1248,20 +663,28 @@ splitAt :: Int -> Text -> (Text, Text)
1248663splitAt n t@(Text arr off len)
1249664 | n <= 0 = (empty, t)
1250665 | n >= len = (t, empty)
1251− | otherwise = let k = iterN n t
1252− in (text arr off k, text arr (off+k) (len-k))
666+ | otherwise = (Text arr off k, Text arr (off+k) (len-k))
667+ where k = loop 0 0
668+ loop !i !cnt
669+ | i >= len || cnt >= n = i
670+ | otherwise = loop (i+d) (cnt+1)
671+ where d = iter_ t i
672+{-# INLINE splitAt #-}
1253673
1254−-- | /O(n)/ 'span', applied to a predicate @p@ and text @t@, returns
1255−-- a pair whose first element is the longest prefix (possibly empty)
1256−-- of @t@ of elements that satisfy @p@, and whose second is the
1257−-- remainder of the list.
674+-- | /O(n)/ 'span', applied to a predicate @p@ and text @t@, returns a
675+-- pair whose first element is the longest prefix (possibly empty) of
676+-- @t@ of elements that satisfy @p@, and whose second is the remainder
677+-- of the list.
1258678span :: (Char -> Bool) -> Text -> (Text, Text)
1259−span p t = case span_ p t of
1260− (# hd,tl #) -> (hd,tl)
679+span p t@(Text arr off len) = (textP arr off k, textP arr (off+k) (len-k))
680+ where k = loop 0
681+ loop !i | i >= len || not (p c) = i
682+ | otherwise = loop (i+d)
683+ where (c,d) = iter t i
1261684{-# INLINE span #-}
1262685
1263−-- | /O(n)/ 'break' is like 'span', but the prefix returned is
1264−-- over elements that fail the predicate @p@.
686+-- | /O(n)/ 'break' is like 'span', but the prefix returned is over
687+-- elements that fail the predicate @p@.
1265688break :: (Char -> Bool) -> Text -> (Text, Text)
1266689break p = span (not . p)
1267690{-# INLINE break #-}
@@ -1273,7 +696,7 @@ groupBy p = loop
1273696 loop t@(Text arr off len)
1274697 | null t = []
1275698 | otherwise = text arr off n : loop (text arr (off+n) (len-n))
1276− where Iter c d = iter t 0
699+ where (c,d) = iter t 0
1277700 n = d + findAIndexOrEnd (not . p c) (Text arr (off+d) (len-d))
1278701
1279702-- | Returns the /array/ index (in units of 'Word16') at which a
@@ -1283,8 +706,8 @@ findAIndexOrEnd :: (Char -> Bool) -> Text -> Int
1283706findAIndexOrEnd q t@(Text _arr _off len) = go 0
1284707 where go !i | i >= len || q c = i
1285708 | otherwise = go (i+d)
1286− where Iter c d = iter t i
1287−
709+ where (c,d) = iter t i
710+
1288711-- | /O(n)/ Group characters in a string by equality.
1289712group :: Text -> [Text]
1290713group = groupBy (==)
@@ -1302,91 +725,59 @@ tails :: Text -> [Text]
1302725tails t | null t = [empty]
1303726 | otherwise = t : tails (unsafeTail t)
1304727
1305−-- $split
1306−--
1307−-- Splitting functions in this library do not perform character-wise
1308−-- copies to create substrings; they just construct new 'Text's that
1309−-- are slices of the original.
1310−
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.
1314−--
1315−-- Examples:
1316−--
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" == ["",""]
728+-- | /O(n)/ Break a 'Text' into pieces separated by the 'Char'
729+-- argument, consuming the delimiter. I.e.
1320730--
731+-- > split '\n' "a\nb\nd\ne" == ["a","b","d","e"]
732+-- > split 'a' "aXaXaXa" == ["","X","X","X",""]
733+-- > split 'x' "x" == ["",""]
734+--
1321735-- and
1322736--
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.)
1327−--
1328−-- In (unlikely) bad cases, this function's time complexity degrades
1329−-- 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
1339− | otherwise = go 0 (indices pat src)
1340− 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 #-}
1344−
1345−{-# RULES
1346−"TEXT splitOn/singleton -> split/==" [~1] forall c t.
1347− splitOn (singleton c) t = split (==c) t
1348− #-}
737+-- > intercalate (singleton c) . split c == id
738+-- > split == splitWith . (==)
739+--
740+-- As for all splitting functions in this library, this function does
741+-- not copy the substrings, it just constructs new 'Text's that are
742+-- slices of the original.
743+split :: Char -> Text -> [Text]
744+split c = splitWith (==c)
745+{-# INLINE split #-}
1349746
1350747-- | /O(n)/ Splits a 'Text' into components delimited by separators,
1351748-- where the predicate returns True for a separator element. The
1352749-- resulting components do not contain the separators. Two adjacent
1353750-- separators result in an empty component in the output. eg.
1354751--
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
752+-- > splitWith (=='a') "aabbaca" == ["","","bb","c",""]
753+-- > splitWith (=='a') [] == []
754+splitWith :: (Char -> Bool) -> Text -> [Text]
755+splitWith _ (Text _off _arr 0) = []
756+splitWith p t = loop t
1360757 where loop s | null s' = [l]
1361758 | otherwise = l : loop (unsafeTail s')
1362− where (# l, s' #) = span_ (not . p) s
1363−{-# INLINE split #-}
1364−
1365−-- | /O(n)/ Splits a 'Text' into components of length @k@. The last
1366−-- element may be shorter than the other chunks, depending on the
1367−-- length of the input. Examples:
1368−--
1369−-- > chunksOf 3 "foobarbaz" == ["foo","bar","baz"]
1370−-- > chunksOf 4 "haskell.org" == ["hask","ell.","org"]
1371−chunksOf :: Int -> Text -> [Text]
1372−chunksOf k = go
1373− where
1374− go t = case splitAt k t of
1375− (a,b) | null a -> []
1376− | otherwise -> a : go b
1377−{-# INLINE chunksOf #-}
759+ where (l, s') = break p s
760+{-# INLINE splitWith #-}
1378761
1379762-- ----------------------------------------------------------------------------
1380763-- * Searching
1381764
765+-------------------------------------------------------------------------------
766+-- ** Searching by equality
767+
768+-- | /O(n)/ 'elem' is the 'Text' membership predicate.
769+elem :: Char -> Text -> Bool
770+elem c t = S.elem c (stream t)
771+{-# INLINE elem #-}
772+
1382773-------------------------------------------------------------------------------
1383774-- ** Searching with a predicate
1384775
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.
776+-- | /O(n)/ The 'find' function takes a predicate and a 'Text',
777+-- and returns the first element in matching the predicate, or 'Nothing'
778+-- if there is no such element.
1388779find :: (Char -> Bool) -> Text -> Maybe Char
1389−find p t = S.findBy p (stream t)
780+find p t = S.find p (stream t)
1390781{-# INLINE find #-}
1391782
1392783-- | /O(n)/ The 'partition' function takes a predicate and a 'Text',
@@ -1398,103 +789,49 @@ partition :: (Char -> Bool) -> Text -> (Text, Text)
1398789partition p t = (filter p t, filter (not . p) t)
1399790{-# INLINE partition #-}
1400791
1401−-- | /O(n)/ 'filter', applied to a predicate and a 'Text',
1402−-- returns a 'Text' containing those characters that satisfy the
1403−-- predicate.
1404−filter :: (Char -> Bool) -> Text -> Text
1405−filter p t = unstream (S.filter p (stream t))
1406−{-# INLINE filter #-}
1407−
1408−-- | /O(n+m)/ Find the first instance of @needle@ (which must be
1409−-- non-'null') in @haystack@. The first element of the returned tuple
1410−-- is the prefix of @haystack@ before @needle@ is matched. The second
1411−-- is the remainder of @haystack@, starting with the match.
1412−--
1413−-- Examples:
1414−--
1415−-- > breakOn "::" "a::b::c" ==> ("a", "::b::c")
1416−-- > breakOn "/" "foobar" ==> ("foobar", "")
792+-- | /O(n)/ Break a string on a substring, returning a pair of the
793+-- part of the string prior to the match, and the rest of the string.
1417794--
1418−-- Laws:
795+-- The following relationship holds:
1419796--
1420−-- > append prefix match == haystack
1421−-- > where (prefix, match) = breakOn needle haystack
797+-- > break (==c) l == breakSubstring (singleton c) l
1422798--
1423−-- 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'
1425−-- instead, as it has lower startup overhead.
799+-- For example, to tokenise a string, dropping delimiters:
1426800--
1427−-- In (unlikely) bad cases, this function's time complexity degrades
1428−-- towards /O(n*m)/.
1429−breakOn :: Text -> Text -> (Text, Text)
1430−breakOn pat src@(Text arr off len)
1431− | null pat = emptyError "breakOn"
1432− | otherwise = case indices pat src of
1433− [] -> (src, empty)
1434− (x:_) -> (text arr off x, text arr (off+x) (len-x))
1435−{-# INLINE breakOn #-}
1436−
1437−-- | /O(n+m)/ Similar to 'breakOn', but searches from the end of the
1438−-- string.
801+-- > tokenise x y = h : if null t then [] else tokenise x (drop (length x) t)
802+-- > where (h,t) = breakSubstring x y
1439803--
1440−-- The first element of the returned tuple is the prefix of @haystack@
1441−-- up to and including the last match of @needle@. The second is the
1442−-- remainder of @haystack@, following the match.
804+-- To skip to the first occurence of a string:
1443805--
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 #-}
1449−
1450−-- | /O(n+m)/ Find all non-overlapping instances of @needle@ in
1451−-- @haystack@. Each element of the returned list consists of a pair:
806+-- > snd (breakSubstring x y)
1452807--
1453−-- * The entire string prior to the /k/th match (i.e. the prefix)
808+-- To take the parts of a string before a delimiter:
1454809--
1455−-- * The /k/th match, followed by the remainder of the string
810+-- > fst (breakSubstring x y)
1456811--
1457−-- Examples:
1458−--
1459−-- > breakOnAll "::" ""
1460−-- > ==> []
1461−-- > breakOnAll "/" "a/b/c/"
1462−-- > ==> [("a", "/b/c/"), ("a/b", "/c/"), ("a/b/c", "/")]
1463−--
1464−-- In (unlikely) bad cases, this function's time complexity degrades
1465−-- 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)
812+breakSubstring :: Text -- ^ String to search for
813+ -> Text -- ^ String to search in
814+ -> (Text,Text) -- ^ Head and tail of string broken at substring
815+
816+breakSubstring pat src = search 0 src
1474817 where
1475− step x = (chunk 0 x, chunk x (slen-x))
1476− chunk !n !l = text arr (n+off) l
1477−{-# INLINE breakOnAll #-}
818+ search !n !s
819+ | null s = (src,empty) -- not found
820+ | pat `isPrefixOf` s = (take n src,s)
821+ | otherwise = search (n+1) (unsafeTail s)
822+{-# INLINE breakSubstring #-}
823+
824+-- | /O(n)/ 'filter', applied to a predicate and a 'Text',
825+-- returns a 'Text' containing those characters that satisfy the
826+-- predicate.
827+filter :: (Char -> Bool) -> Text -> Text
828+filter p t = unstream (S.filter p (stream t))
829+{-# INLINE filter #-}
830+
1478831
1479832-------------------------------------------------------------------------------
1480833-- ** Indexing 'Text's
1481834
1482−-- $index
1483−--
1484−-- If you think of a 'Text' value as an array of 'Char' values (which
1485−-- it is not), you run the risk of writing inefficient code.
1486−--
1487−-- An idiom that is common in some languages is to find the numeric
1488−-- offset of a character or substring, then use that number to split
1489−-- or trim the searched string. With a 'Text' value, this approach
1490−-- would require two /O(n)/ operations: one to perform the search, and
1491−-- one to operate from wherever the search ended.
1492−--
1493−-- For example, suppose you have a string that you want to split on
1494−-- the substring @\"::\"@, such as @\"foo::bar::quux\"@. Instead of
1495−-- searching for the index of @\"::\"@ and taking the substrings
1496−-- before and after that index, you would instead use @breakOnAll \"::\"@.
1497−
1498835-- | /O(n)/ 'Text' index (subscript) operator, starting from 0.
1499836index :: Text -> Int -> Char
1500837index t n = S.index (stream t) n
@@ -1502,34 +839,39 @@ index t n = S.index (stream t) n
1502839
1503840-- | /O(n)/ The 'findIndex' function takes a predicate and a 'Text'
1504841-- and returns the index of the first element in the 'Text' satisfying
1505−-- the predicate. Subject to fusion.
842+-- the predicate. This function is subject to fusion.
1506843findIndex :: (Char -> Bool) -> Text -> Maybe Int
1507844findIndex p t = S.findIndex p (stream t)
1508845{-# INLINE findIndex #-}
1509846
1510−-- | /O(n+m)/ The 'count' function returns the number of times the
1511−-- query string appears in the given 'Text'. An empty query string is
1512−-- invalid, and will cause an error to be raised.
1513−--
1514−-- In (unlikely) bad cases, this function's time complexity degrades
1515−-- towards /O(n*m)/.
1516−count :: Text -> Text -> Int
1517−count pat src
1518− | null pat = emptyError "count"
1519− | isSingleton pat = countChar (unsafeHead pat) src
1520− | otherwise = L.length (indices pat src)
1521−{-# INLINE [1] count #-}
1522−
1523−{-# RULES
1524−"TEXT count/singleton -> countChar" [~1] forall c t.
1525− count (singleton c) t = countChar c t
1526− #-}
847+-- | The 'findIndices' function extends 'findIndex', by returning the
848+-- indices of all elements satisfying the predicate, in ascending
849+-- order. This function is subject to fusion.
850+findIndices :: (Char -> Bool) -> Text -> [Int]
851+findIndices p t = S.findIndices p (stream t)
852+{-# INLINE findIndices #-}
1527853
1528−-- | /O(n)/ The 'countChar' function returns the number of times the
1529−-- query element appears in the given 'Text'. Subject to fusion.
1530−countChar :: Char -> Text -> Int
1531−countChar c t = S.countChar c (stream t)
1532−{-# INLINE countChar #-}
854+-- | /O(n)/ The 'elemIndex' function returns the index of the first
855+-- element in the given 'Text' which is equal to the query element, or
856+-- 'Nothing' if there is no such element. This function is subject to
857+-- fusion.
858+elemIndex :: Char -> Text -> Maybe Int
859+elemIndex c t = S.elemIndex c (stream t)
860+{-# INLINE elemIndex #-}
861+
862+-- | /O(n)/ The 'elemIndices' function returns the index of every
863+-- element in the given 'Text' which is equal to the query
864+-- element. This function is subject to fusion.
865+elemIndices :: Char -> Text -> [Int]
866+elemIndices c t = S.elemIndices c (stream t)
867+{-# INLINE elemIndices #-}
868+
869+-- | /O(n)/ The 'count' function returns the number of times the query
870+-- element appears in the given 'Text'. This function is subject to
871+-- fusion.
872+count :: Char -> Text -> Int
873+count c t = S.count c (stream t)
874+{-# INLINE count #-}
1533875
1534876-------------------------------------------------------------------------------
1535877-- * Zipping
@@ -1540,15 +882,13 @@ countChar c t = S.countChar c (stream t)
1540882-- equivalent to a pair of 'unpack' operations.
1541883zip :: Text -> Text -> [(Char,Char)]
1542884zip a b = S.unstreamList $ S.zipWith (,) (stream a) (stream b)
1543−{-# INLINE zip #-}
885+{-# INLINE [0] zip #-}
1544886
1545887-- | /O(n)/ 'zipWith' generalises 'zip' by zipping with the function
1546888-- given as the first argument, instead of a tupling function.
1547−-- Performs replacement on invalid scalar values.
1548889zipWith :: (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 #-}
890+zipWith f t1 t2 = unstream (S.zipWith f (stream t1) (stream t2))
891+{-# INLINE [0] zipWith #-}
1552892
1553893-- | /O(n)/ Breaks a 'Text' up into a list of words, delimited by 'Char's
1554894-- representing white space.
@@ -1564,7 +904,7 @@ words t@(Text arr off len) = loop 0 0
1564904 then loop (start+1) (start+1)
1565905 else Text arr (start+off) (n-start) : loop (n+d) (n+d)
1566906 | otherwise = loop start (n+d)
1567− where Iter c d = iter t n
907+ where (c,d) = iter t n
1568908{-# INLINE words #-}
1569909
1570910-- | /O(n)/ Breaks a 'Text' up into a list of 'Text's at
@@ -1574,10 +914,9 @@ lines ps | null ps = []
1574914 | otherwise = h : if null t
1575915 then []
1576916 else lines (unsafeTail t)
1577− where (# h,t #) = span_ (/= '\n') ps
917+ where (h,t) = span (/= '\n') ps
1578918{-# INLINE lines #-}
1579919
1580−{-
1581920-- | /O(n)/ Portably breaks a 'Text' up into a list of 'Text's at line
1582921-- boundaries.
1583922--
@@ -1585,6 +924,7 @@ lines ps | null ps = []
1585924-- return immediately followed by a line feed, or a carriage return.
1586925-- This accounts for both Unix and Windows line ending conventions,
1587926-- and for the old convention used on Mac OS 9 and earlier.
927+{-
1588928lines' :: Text -> [Text]
1589929lines' ps | null ps = []
1590930 | otherwise = h : case uncons t of
@@ -1611,7 +951,8 @@ unwords = intercalate (singleton ' ')
1611951{-# INLINE unwords #-}
1612952
1613953-- | /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.
954+-- 'True' iff the first is a prefix of the second. This function is
955+-- subject to fusion.
1615956isPrefixOf :: Text -> Text -> Bool
1616957isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) =
1617958 alen <= blen && S.isPrefixOf (stream a) (stream b)
@@ -1620,6 +961,8 @@ isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) =
1620961{-# RULES
1621962"TEXT isPrefixOf -> fused" [~1] forall s t.
1622963 isPrefixOf s t = S.isPrefixOf (stream s) (stream t)
964+"TEXT isPrefixOf -> unfused" [1] forall s t.
965+ S.isPrefixOf (stream s) (stream t) = isPrefixOf s t
1623966 #-}
1624967
1625968-- | /O(n)/ The 'isSuffixOf' function takes two 'Text's and returns
@@ -1632,124 +975,13 @@ isSuffixOf a@(Text _aarr _aoff alen) b@(Text barr boff blen) =
1632975 | otherwise = Text barr (boff+d) alen
1633976{-# INLINE isSuffixOf #-}
1634977
1635−-- | /O(n+m)/ The 'isInfixOf' function takes two 'Text's and returns
978+-- | /O(n)/ The 'isInfixOf' function takes two 'Text's and returns
1636979-- 'True' iff the first is contained, wholly and intact, anywhere
1637980-- within the second.
1638−--
1639−-- In (unlikely) bad cases, this function's time complexity degrades
1640−-- towards /O(n*m)/.
1641981isInfixOf :: Text -> Text -> Bool
1642−isInfixOf needle haystack
1643− | null needle = True
1644− | isSingleton needle = S.elem (unsafeHead needle) . S.stream $ haystack
1645− | otherwise = not . L.null . indices needle $ haystack
1646−{-# INLINE [1] isInfixOf #-}
1647−
1648−{-# RULES
1649−"TEXT isInfixOf/singleton -> S.elem/S.stream" [~1] forall n h.
1650− isInfixOf (singleton n) h = S.elem n (S.stream h)
1651− #-}
1652−
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
982+isInfixOf needle haystack = L.any (isPrefixOf needle) (tails haystack)
983+{-# INLINE isInfixOf #-}
984+-- TODO: a better implementation
1733985
1734986emptyError :: 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
987+emptyError fun = P.error ("Data.Text." ++ fun ++ ": empty input")