@@ -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
@@ -76,17 +56,11 @@ module Data.Text
7656 , reverse
7757 , replace
7858
79− -- ** Case conversion
59+ -- * Case conversion
8060 -- $case
8161 , toCaseFold
8262 , toLower
8363 , toUpper
84− , toTitle
85−
86− -- ** Justification
87− , justifyLeft
88− , justifyRight
89− , center
9064
9165 -- * Folds
9266 , foldl
@@ -125,22 +99,17 @@ module Data.Text
12599
126100 -- ** Breaking strings
127101 , take
128− , takeEnd
129102 , drop
130− , dropEnd
131103 , takeWhile
132− , takeWhileEnd
133104 , dropWhile
134− , dropWhileEnd
105+ , dropAfter
135106 , dropAround
136107 , strip
137− , stripStart
138− , stripEnd
108+ , stripLeft
109+ , stripRight
139110 , splitAt
140− , breakOn
141− , breakOnEnd
142− , break
143111 , span
112+ , break
144113 , group
145114 , groupBy
146115 , inits
@@ -148,8 +117,10 @@ module Data.Text
148117
149118 -- ** Breaking into many substrings
150119 -- $split
151− , splitOn
152120 , split
121+ , splitTimes
122+ , splitChar
123+ , splitWith
153124 , chunksOf
154125
155126 -- ** Breaking into lines and words
@@ -164,309 +135,137 @@ module Data.Text
164135 , isSuffixOf
165136 , isInfixOf
166137
167− -- ** View patterns
168− , stripPrefix
169− , stripSuffix
170− , commonPrefixes
171−
172138 -- * Searching
139+ , elem
173140 , filter
174− , breakOnAll
175141 , find
176142 , partition
177143
178144 -- , findSubstring
179−
145+
180146 -- * Indexing
181− -- $index
182147 , index
183148 , findIndex
149+ , findIndices
150+ , elemIndex
151+ , elemIndices
184152 , count
185153
186− -- * Zipping
154+ -- * Zipping and unzipping
187155 , zip
188156 , zipWith
189157
190158 -- -* Ordered text
191159 -- , sort
192−
193− -- * Low level operations
194− , copy
195− , unpackCString#
196160 ) where
197161
198−import Prelude (Char, Bool(..), Int, Maybe(..), String,
199− Eq(..), Ord(..), Ordering(..), (++),
200− Read(..),
201− (&&), (||), (+), (-), (.), ($), ($!), (>>),
202− not, return, otherwise, quot)
203−#if defined(HAVE_DEEPSEQ)
204−import Control.DeepSeq (NFData(rnf))
205−#endif
206−#if defined(ASSERTS)
162+import Prelude (Char, Bool(..), Functor(..), Int, Maybe(..), String,
163+ Eq(..), Ord(..), (++),
164+ Read(..), Show(..),
165+ (&&), (||), (+), (-), (.), ($),
166+ not, return, otherwise)
207167import Control.Exception (assert)
208−#endif
209168import 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)
213169import Control.Monad.ST (ST)
214170import qualified Data.Text.Array as A
215171import qualified Data.List as L
216−import Data.Binary (Binary(get, put))
217172import Data.Monoid (Monoid(..))
218−#if MIN_VERSION_base(4,9,0)
219−import Data.Semigroup (Semigroup(..))
220−#endif
173+import Data.Word (Word16)
221174import 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.
269175
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 >.)
176+import qualified Data.Text.Fusion as S
177+import qualified Data.Text.Fusion.Common as S
178+import Data.Text.Fusion (stream, reverseStream, unstream)
179+
180+import Data.Text.Internal (Text(..), empty, text, textP)
181+import qualified Prelude as P
182+import Data.Text.Unsafe (iter, iter_, reverseIter, unsafeHead, unsafeTail)
183+import Data.Text.UnsafeChar (unsafeChr)
184+import qualified Data.Text.Encoding.Utf16 as U16
298185
299186-- $fusion
300187--
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\".
188+-- Most of the functions in this module are subject to /array fusion/,
189+-- meaning that a pipeline of functions will usually allocate at most
190+-- one 'Text' value.
323191
324192instance 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
193+ t1 == t2 = stream t1 == stream t2
328194 {-# INLINE (==) #-}
329195
330196instance Ord Text where
331− compare = compareText
197+ compare t1 t2 = compare (stream t1) (stream t2)
198+ {-# INLINE compare #-}
199+
200+instance Show Text where
201+ showsPrec p ps r = showsPrec p (unpack ps) r
332202
333203instance Read Text where
334204 readsPrec p str = [(pack x,y) | (x,y) <- readsPrec p str]
335205
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−
344206instance Monoid Text where
345207 mempty = empty
346−#if MIN_VERSION_base(4,9,0)
347− mappend = (<>) -- future-proof definition
348−#else
349208 mappend = append
350−#endif
351209 mconcat = concat
352210
353211instance IsString Text where
354212 fromString = pack
355213
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−
424214-- -----------------------------------------------------------------------------
425215-- * Conversion to/from 'Text'
426216
427−-- | /O(n)/ Convert a 'String' into a 'Text'. Subject to
428−-- fusion. Performs replacement on invalid scalar values.
217+-- | /O(n)/ Convert a 'String' into a 'Text'.
218+--
219+-- This function is subject to array fusion.
429220pack :: String -> Text
430−pack = unstream . S.map safe . S.streamList
221+pack = unstream . S.streamList
431222{-# INLINE [1] pack #-}
432223
224+-- | /O(n)/ Convert a Text into a String.
225+-- Subject to array fusion.
226+unpack :: Text -> String
227+unpack = S.unstreamList . stream
228+{-# INLINE [1] unpack #-}
229+
230+-- | /O(1)/ Convert a character into a Text.
231+-- Subject to array fusion.
232+singleton :: Char -> Text
233+singleton = unstream . S.singleton
234+{-# INLINE [1] singleton #-}
235+
433236-- -----------------------------------------------------------------------------
434237-- * Basic functions
435238
436239-- | /O(n)/ Adds a character to the front of a 'Text'. This function
437240-- 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.
241+-- copying a new array. Subject to array fusion.
440242cons :: Char -> Text -> Text
441−cons c t = unstream (S.cons (safe c) (stream t))
243+cons c t = unstream (S.cons c (stream t))
442244{-# INLINE cons #-}
443245
444−infixr 5 `cons`
445−
446246-- | /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.
247+-- entire array in the process. Subject to array fusion.
449248snoc :: Text -> Char -> Text
450−snoc t c = unstream (S.snoc (stream t) (safe c))
249+snoc t c = unstream (S.snoc (stream t) c)
451250{-# INLINE snoc #-}
452251
453252-- | /O(n)/ Appends one 'Text' to the other by copying both of them
454−-- into a new 'Text'. Subject to fusion.
253+-- into a new 'Text'. Subject to array fusion.
455254append :: 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"
255+append (Text arr1 off1 len1) (Text arr2 off2 len2) = Text (A.run x) 0 len
461256 where
462257 len = len1+len2
463− x :: ST s (A.MArray s)
464258 x = do
465− arr <- A.new len
466− A.copyI arr 0 arr1 off1 len1
467− A.copyI arr len1 arr2 off2 len
259+ arr <- A.unsafeNew len :: ST s (A.MArray s Word16)
260+ copy arr1 off1 (len1+off1) arr 0
261+ copy arr2 off2 (len2+off2) arr len1
468262 return arr
469−{-# NOINLINE append #-}
263+ where
264+ copy arr i top arr' j
265+ | i >= top = return ()
266+ | otherwise = do A.unsafeWrite arr' j (arr `A.unsafeIndex` i)
267+ copy arr (i+1) top arr' (j+1)
268+{-# INLINE append #-}
470269
471270{-# RULES
472271"TEXT append -> fused" [~1] forall t1 t2.
@@ -476,26 +275,33 @@ append a@(Text arr1 off1 len1) b@(Text arr2 off2 len2)
476275 #-}
477276
478277-- | /O(1)/ Returns the first character of a 'Text', which must be
479−-- non-empty. Subject to fusion.
278+-- non-empty. Subject to array fusion.
480279head :: Text -> Char
481280head t = S.head (stream t)
482281{-# INLINE head #-}
483282
484283-- | /O(1)/ Returns the first character and rest of a 'Text', or
485−-- 'Nothing' if empty. Subject to fusion.
284+-- 'Nothing' if empty. Subject to array fusion.
486285uncons :: Text -> Maybe (Char, Text)
487286uncons t@(Text arr off len)
488287 | 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 #-}
288+ | otherwise = Just (c, textP arr (off+d) (len-d))
289+ where (c,d) = iter t 0
290+{-# INLINE uncons #-}
492291
493292-- | Lifted from Control.Arrow and specialized.
494293second :: (b -> c) -> (a,b) -> (a,c)
495294second f (a, b) = (a, f b)
496295
296+{-# RULES
297+"TEXT uncons -> fused" [~1] forall t.
298+ uncons t = fmap (second unstream) (S.uncons (stream t))
299+"TEXT uncons -> unfused" [1] forall t.
300+ fmap (second unstream) (S.uncons (stream t)) = uncons t
301+ #-}
302+
497303-- | /O(1)/ Returns the last character of a 'Text', which must be
498−-- non-empty. Subject to fusion.
304+-- non-empty. Subject to array fusion.
499305last :: Text -> Char
500306last (Text arr off len)
501307 | len <= 0 = emptyError "last"
@@ -513,11 +319,11 @@ last (Text arr off len)
513319 #-}
514320
515321-- | /O(1)/ Returns all characters after the head of a 'Text', which
516−-- must be non-empty. Subject to fusion.
322+-- must be non-empty. Subject to array fusion.
517323tail :: Text -> Text
518324tail t@(Text arr off len)
519325 | len <= 0 = emptyError "tail"
520− | otherwise = text arr (off+d) (len-d)
326+ | otherwise = textP arr (off+d) (len-d)
521327 where d = iter_ t 0
522328{-# INLINE [1] tail #-}
523329
@@ -529,11 +335,11 @@ tail t@(Text arr off len)
529335 #-}
530336
531337-- | /O(1)/ Returns all but the last character of a 'Text', which must
532−-- be non-empty. Subject to fusion.
338+-- be non-empty. Subject to array fusion.
533339init :: Text -> Text
534340init (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)
341+ | n >= 0xDC00 && n <= 0xDFFF = textP arr off (len-2)
342+ | otherwise = textP arr off (len-1)
537343 where
538344 n = A.unsafeIndex arr (off+len-1)
539345{-# INLINE [1] init #-}
@@ -545,14 +351,10 @@ init (Text arr off len) | len <= 0 = emptyError "init"
545351 unstream (S.init (stream t)) = init t
546352 #-}
547353
548−-- | /O(1)/ Tests whether a 'Text' is empty or not. Subject to
354+-- | /O(1)/ Tests whether a 'Text' is empty or not. Subject to array
549355-- fusion.
550356null :: Text -> Bool
551−null (Text _arr _off len) =
552−#if defined(ASSERTS)
553− assert (len >= 0) $
554−#endif
555− len <= 0
357+null (Text _arr _off len) = assert (len >= 0) $ len <= 0
556358{-# INLINE [1] null #-}
557359
558360{-# RULES
@@ -562,171 +364,61 @@ null (Text _arr _off len) =
562364 S.null (stream t) = null t
563365 #-}
564366
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−
571367-- | /O(n)/ Returns the number of characters in a 'Text'.
572−-- Subject to fusion.
368+-- Subject to array fusion.
573369length :: Text -> Int
574370length 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− #-}
371+{-# INLINE length #-}
623372
624373-- -----------------------------------------------------------------------------
625374-- * Transformations
626375-- | /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.
376+-- each element of @t@. Subject to array fusion.
629377map :: (Char -> Char) -> Text -> Text
630−map f t = unstream (S.map (safe . f) (stream t))
378+map f t = unstream (S.map f (stream t))
631379{-# INLINE [1] map #-}
632380
633381-- | /O(n)/ The 'intercalate' function takes a 'Text' and a list of
634382-- 'Text's and concatenates the list after interspersing the first
635383-- argument between each element of the list.
636384intercalate :: Text -> [Text] -> Text
637−intercalate t = concat . (F.intersperse t)
385+intercalate t ts = unstream (S.intercalate (stream t) (L.map stream ts))
638386{-# INLINE intercalate #-}
639387
640388-- | /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.
389+-- between the characters of a 'Text'. Subject to array fusion.
643390intersperse :: Char -> Text -> Text
644−intersperse c t = unstream (S.intersperse (safe c) (stream t))
391+intersperse c t = unstream (S.intersperse c (stream t))
645392{-# INLINE intersperse #-}
646393
647−-- | /O(n)/ Reverse the characters of a string. Subject to fusion.
394+-- | /O(n)/ Reverse the characters of a string. Subject to array fusion.
648395reverse :: Text -> Text
649396reverse t = S.reverse (stream t)
650397{-# INLINE reverse #-}
651398
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.
399+-- | /O(m)*O(n)/ Replace every occurrence of one substring with another.
400+replace :: Text -- ^ Text to search for
401+ -> Text -- ^ Replacement text
402+ -> Text -- ^ Input text
680403 -> 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
404+replace s d = intercalate d . split s
405+{-# INLINE replace #-}
705406
706407-- ----------------------------------------------------------------------------
707408-- ** Case conversions (folds)
708409
709410-- $case
710411--
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 >.
412+-- When case converting Unicode text, it is incorrect to use
413+-- combinators like @map toUpper@ to case convert each character of a
414+-- string individually. Instead, use the whole-string case conversion
415+-- functions from this module. For correctness in different writing
416+-- systems, these functions may map one input character to two or
417+-- three output characters.
725418
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.
419+-- | /O(n)/ Convert a string to folded case. This function is mainly
420+-- useful for performing caseless (or case insensitive) string
421+-- comparisons.
730422--
731423-- A string @x@ is a caseless match for a string @y@ if and only if:
732424--
@@ -741,105 +433,25 @@ replace needle@(Text _ _ neeLen)
741433-- instead of itself.
742434toCaseFold :: Text -> Text
743435toCaseFold t = unstream (S.toCaseFold (stream t))
744−{-# INLINE toCaseFold #-}
436+{-# INLINE [0] toCaseFold #-}
745437
746438-- | /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).
439+-- conversion. The result string may be longer than the input string.
440+-- For instance, \"İ\" (Latin capital letter I with dot above,
441+-- U+0130) maps to the sequence \"i\" (Latin small letter i, U+0069) followed
442+-- by \" ̇\" (combining dot above, U+0307).
753443toLower :: Text -> Text
754444toLower t = unstream (S.toLower (stream t))
755445{-# INLINE toLower #-}
756446
757447-- | /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
448+-- conversion. The result string may be longer than the input string.
449+-- For instance, the German \"ß\" (eszett, U+00DF) maps to the
762450-- two-letter sequence \"SS\".
763451toUpper :: Text -> Text
764452toUpper t = unstream (S.toUpper (stream t))
765453{-# INLINE toUpper #-}
766454
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−
843455-- | /O(n)/ The 'transpose' function transposes the rows and columns
844456-- of its 'Text' argument. Note that this function uses 'pack',
845457-- 'unpack', and the list version of transpose, and is thus not very
@@ -853,23 +465,26 @@ transpose ts = P.map pack (L.transpose (P.map unpack ts))
853465-- | /O(n)/ 'foldl', applied to a binary operator, a starting value
854466-- (typically the left-identity of the operator), and a 'Text',
855467-- reduces the 'Text' using the binary operator, from left to right.
856−-- Subject to fusion.
857−foldl :: (a -> Char -> a) -> a -> Text -> a
468+-- Subject to array fusion.
469+foldl :: (b -> Char -> b) -> b -> Text -> b
858470foldl f z t = S.foldl f z (stream t)
859471{-# INLINE foldl #-}
860472
861−-- | /O(n)/ A strict version of 'foldl'. Subject to fusion.
862−foldl' :: (a -> Char -> a) -> a -> Text -> a
473+-- | /O(n)/ A strict version of 'foldl'.
474+-- Subject to array fusion.
475+foldl' :: (b -> Char -> b) -> b -> Text -> b
863476foldl' f z t = S.foldl' f z (stream t)
864477{-# INLINE foldl' #-}
865478
866479-- | /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.
480+-- and thus must be applied to a non-empty 'Text'. Subject to array
481+-- fusion.
868482foldl1 :: (Char -> Char -> Char) -> Text -> Char
869483foldl1 f t = S.foldl1 f (stream t)
870484{-# INLINE foldl1 #-}
871485
872−-- | /O(n)/ A strict version of 'foldl1'. Subject to fusion.
486+-- | /O(n)/ A strict version of 'foldl1'.
487+-- Subject to array fusion.
873488foldl1' :: (Char -> Char -> Char) -> Text -> Char
874489foldl1' f t = S.foldl1' f (stream t)
875490{-# INLINE foldl1' #-}
@@ -877,13 +492,13 @@ foldl1' f t = S.foldl1' f (stream t)
877492-- | /O(n)/ 'foldr', applied to a binary operator, a starting value
878493-- (typically the right-identity of the operator), and a 'Text',
879494-- reduces the 'Text' using the binary operator, from right to left.
880−-- Subject to fusion.
881−foldr :: (Char -> a -> a) -> a -> Text -> a
495+-- Subject to array fusion.
496+foldr :: (Char -> b -> b) -> b -> Text -> b
882497foldr f z t = S.foldr f z (stream t)
883498{-# INLINE foldr #-}
884499
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
500+-- | /O(n)/ A variant of 'foldr' that has no starting value argument, and
501+-- thust must be applied to a non-empty 'Text'. Subject to array
887502-- fusion.
888503foldr1 :: (Char -> Char -> Char) -> Text -> Char
889504foldr1 f t = S.foldr1 f (stream t)
@@ -892,48 +507,40 @@ foldr1 f t = S.foldr1 f (stream t)
892507-- -----------------------------------------------------------------------------
893508-- ** Special folds
894509
895−-- | /O(n)/ Concatenate a list of 'Text's.
510+-- | /O(n)/ Concatenate a list of 'Text's. Subject to array fusion.
896511concat :: [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
512+concat ts = unstream (S.concat (L.map stream ts))
513+{-# INLINE concat #-}
910514
911515-- | /O(n)/ Map a function over a 'Text' that results in a 'Text', and
912−-- concatenate the results.
516+-- concatenate the results. This function is subject to array fusion.
517+--
518+-- Note: if in 'concatMap' @f@ @t@, @f@ is defined in terms of fusible
519+-- functions, it will also be fusible.
913520concatMap :: (Char -> Text) -> Text -> Text
914−concatMap f = concat . foldr ((:) . f) []
521+concatMap f t = unstream (S.concatMap (stream . f) (stream t))
915522{-# INLINE concatMap #-}
916523
917524-- | /O(n)/ 'any' @p@ @t@ determines whether any character in the
918−-- 'Text' @t@ satisfies the predicate @p@. Subject to fusion.
525+-- 'Text' @t@ satisifes the predicate @p@. Subject to array fusion.
919526any :: (Char -> Bool) -> Text -> Bool
920527any p t = S.any p (stream t)
921528{-# INLINE any #-}
922529
923530-- | /O(n)/ 'all' @p@ @t@ determines whether all characters in the
924−-- 'Text' @t@ satisfy the predicate @p@. Subject to fusion.
531+-- 'Text' @t@ satisify the predicate @p@. Subject to array fusion.
925532all :: (Char -> Bool) -> Text -> Bool
926533all p t = S.all p (stream t)
927534{-# INLINE all #-}
928535
929536-- | /O(n)/ 'maximum' returns the maximum value from a 'Text', which
930−-- must be non-empty. Subject to fusion.
537+-- must be non-empty. Subject to array fusion.
931538maximum :: Text -> Char
932539maximum t = S.maximum (stream t)
933540{-# INLINE maximum #-}
934541
935542-- | /O(n)/ 'minimum' returns the minimum value from a 'Text', which
936−-- must be non-empty. Subject to fusion.
543+-- must be non-empty. Subject to array fusion.
937544minimum :: Text -> Char
938545minimum t = S.minimum (stream t)
939546{-# INLINE minimum #-}
@@ -942,8 +549,8 @@ minimum t = S.minimum (stream t)
942549-- * Building 'Text's
943550
944551-- | /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.
552+-- successive reduced values from the left. This function is subject
553+-- to array fusion.
947554--
948555-- > scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]
949556--
@@ -951,13 +558,11 @@ minimum t = S.minimum (stream t)
951558--
952559-- > last (scanl f z xs) == foldl f z xs.
953560scanl :: (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)
561+scanl f z t = unstream (S.scanl f z (stream t))
956562{-# INLINE scanl #-}
957563
958564-- | /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.
565+-- value argument. This function is subject to array fusion.
961566--
962567-- > scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]
963568scanl1 :: (Char -> Char -> Char) -> Text -> Text
@@ -965,75 +570,49 @@ scanl1 f t | null t = empty
965570 | otherwise = scanl f (unsafeHead t) (unsafeTail t)
966571{-# INLINE scanl1 #-}
967572
968−-- | /O(n)/ 'scanr' is the right-to-left dual of 'scanl'. Performs
969−-- replacement on invalid scalar values.
573+-- | /O(n)/ 'scanr' is the right-to-left dual of 'scanl'.
970574--
971575-- > scanr f v == reverse . scanl (flip f) v . reverse
972576scanr :: (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)
577+scanr f z = S.reverse . S.reverseScanr f z . reverseStream
975578{-# INLINE scanr #-}
976579
977580-- | /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.
581+-- value argument. This function is subject to array fusion.
980582scanr1 :: (Char -> Char -> Char) -> Text -> Text
981583scanr1 f t | null t = empty
982584 | otherwise = scanr f (last t) (init t)
983585{-# INLINE scanr1 #-}
984586
985−-- | /O(n)/ Like a combination of 'map' and 'foldl''. Applies a
587+-- | /O(n)/ Like a combination of 'map' and 'foldl'. Applies a
986588-- 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.
589+-- parameter from left to right, and returns a final 'Text'.
989590mapAccumL :: (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 #-}
591+mapAccumL f s t = case uncons t of
592+ Nothing -> (s, empty)
593+ Just (x, xs) -> (s'', cons y ys)
594+ where (s', y ) = f s x
595+ (s'',ys) = mapAccumL f s' xs
993596
994597-- | 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.
598+-- 'foldr'; it applies a function to each element of a 'Text', passing
599+-- an accumulating parameter from right to left, and returning a final
600+-- value of this accumulator together with the new 'Text'.
1000601mapAccumR :: (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 #-}
602+mapAccumR f s t = case uncons t of
603+ Nothing -> (s, empty)
604+ Just (x, xs) -> (s'', cons y ys)
605+ where (s'',y ) = f s' x
606+ (s', ys) = mapAccumR f s xs
1004607
1005608-- -----------------------------------------------------------------------------
1006609-- ** Generating and unfolding 'Text's
1007610
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
611+-- | /O(n)/ 'replicate' @n@ @c@ is a 'Text' of length @n@ with @c@ the
1033612-- 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 #-}
613+replicate :: Int -> Char -> Text
614+replicate n c = unstream (S.replicate n c)
615+{-# INLINE replicate #-}
1037616
1038617-- | /O(n)/, where @n@ is the length of the result. The 'unfoldr'
1039618-- function is analogous to the List 'L.unfoldr'. 'unfoldr' builds a
@@ -1041,9 +620,9 @@ replicateChar n c = unstream (S.replicateCharI n (safe c))
1041620-- returns 'Nothing' if it is done producing the 'Text', otherwise
1042621-- 'Just' @(a,b)@. In this case, @a@ is the next 'Char' in the
1043622-- string, and @b@ is the seed value for further production. Subject
1044−-- to fusion. Performs replacement on invalid scalar values.
623+-- to fusion.
1045624unfoldr :: (a -> Maybe (Char,a)) -> a -> Text
1046−unfoldr f s = unstream (S.unfoldr (firstf safe . f) s)
625+unfoldr f s = unstream (S.unfoldr f s)
1047626{-# INLINE unfoldr #-}
1048627
1049628-- | /O(n)/ Like 'unfoldr', 'unfoldrN' builds a 'Text' from a seed
@@ -1051,9 +630,9 @@ unfoldr f s = unstream (S.unfoldr (firstf safe . f) s)
1051630-- first argument to 'unfoldrN'. This function is more efficient than
1052631-- 'unfoldr' when the maximum length of the result is known and
1053632-- correct, otherwise its performance is similar to 'unfoldr'. Subject
1054−-- to fusion. Performs replacement on invalid scalar values.
633+-- to fusion.
1055634unfoldrN :: Int -> (a -> Maybe (Char,a)) -> a -> Text
1056−unfoldrN n f s = unstream (S.unfoldrN n (firstf safe . f) s)
635+unfoldrN n f s = unstream (S.unfoldrN n f s)
1057636{-# INLINE unfoldrN #-}
1058637
1059638-- -----------------------------------------------------------------------------
@@ -1066,16 +645,14 @@ take :: Int -> Text -> Text
1066645take n t@(Text arr off len)
1067646 | n <= 0 = empty
1068647 | n >= len = t
1069− | otherwise = text arr off (iterN n t)
648+ | otherwise = Text arr off (loop 0 0)
649+ where
650+ loop !i !cnt
651+ | i >= len || cnt >= n = i
652+ | otherwise = loop (i+d) (cnt+1)
653+ where d = iter_ t i
1070654{-# INLINE [1] take #-}
1071655
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−
1079656{-# RULES
1080657"TEXT take -> fused" [~1] forall n t.
1081658 take n t = unstream (S.take n (stream t))
@@ -1083,36 +660,18 @@ iterN n t@(Text _arr _off len) = loop 0 0
1083660 unstream (S.take n (stream t)) = take n t
1084661 #-}
1085662
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−
1107663-- | /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.
664+-- 'Text' of length @n@, or the empty 'Text' if @n@ is greater than the
665+-- length of the 'Text'. Subject to fusion.
1110666drop :: Int -> Text -> Text
1111667drop n t@(Text arr off len)
1112668 | n <= 0 = t
1113669 | n >= len = empty
1114− | otherwise = text arr (off+i) (len-i)
1115− where i = iterN n t
670+ | otherwise = loop 0 0
671+ where loop !i !cnt
672+ | i >= len || cnt >= n = Text arr (off+i) (len-i)
673+ | otherwise = loop (i+d) (cnt+1)
674+ where d = iter_ t i
1116675{-# INLINE [1] drop #-}
1117676
1118677{-# RULES
@@ -1122,27 +681,15 @@ drop n t@(Text arr off len)
1122681 unstream (S.drop n (stream t)) = drop n t
1123682 #-}
1124683
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.
684+-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text', returns
685+-- the longest prefix (possibly empty) of elements that satisfy @p@.
686+-- This function is subject to array fusion.
1140687takeWhile :: (Char -> Bool) -> Text -> Text
1141688takeWhile p t@(Text arr off len) = loop 0
1142689 where loop !i | i >= len = t
1143690 | p c = loop (i+d)
1144− | otherwise = text arr off i
1145− where Iter c d = iter t i
691+ | otherwise = textP arr off i
692+ where (c,d) = iter t i
1146693{-# INLINE [1] takeWhile #-}
1147694
1148695{-# RULES
@@ -1152,35 +699,14 @@ takeWhile p t@(Text arr off len) = loop 0
1152699 unstream (S.takeWhile p (stream t)) = takeWhile p t
1153700 #-}
1154701
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−
1176702-- | /O(n)/ 'dropWhile' @p@ @t@ returns the suffix remaining after
1177−-- 'takeWhile' @p@ @t@. Subject to fusion.
703+-- 'takeWhile' @p@ @t@. This function is subject to array fusion.
1178704dropWhile :: (Char -> Bool) -> Text -> Text
1179705dropWhile p t@(Text arr off len) = loop 0 0
1180706 where loop !i !l | l >= len = empty
1181707 | p c = loop (i+d) (l+d)
1182708 | otherwise = Text arr (off+i) (len-l)
1183− where Iter c d = iter t i
709+ where (c,d) = iter t i
1184710{-# INLINE [1] dropWhile #-}
1185711
1186712{-# RULES
@@ -1190,48 +716,45 @@ dropWhile p t@(Text arr off len) = loop 0 0
1190716 unstream (S.dropWhile p (stream t)) = dropWhile p t
1191717 #-}
1192718
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
719+-- | /O(n)/ 'dropAfter' @p@ @t@ returns the prefix remaining after
720+-- dropping characters that fail the predicate @p@ from the end of
721+-- @t@. This function is subject to array fusion.
722+dropAfter :: (Char -> Bool) -> Text -> Text
723+dropAfter p t@(Text arr off len) = loop (len-1) len
1202724 where loop !i !l | l <= 0 = empty
1203725 | p c = loop (i+d) (l+d)
1204726 | otherwise = Text arr off l
1205727 where (c,d) = reverseIter t i
1206−{-# INLINE [1] dropWhileEnd #-}
728+{-# INLINE [1] dropAfter #-}
1207729
1208730{-# 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
731+"TEXT dropAfter -> fused" [~1] forall p t.
732+ dropAfter p t = S.reverse (S.dropWhile p (S.reverseStream t))
733+"TEXT dropAfter -> unfused" [1] forall p t.
734+ S.reverse (S.dropWhile p (S.reverseStream t)) = dropAfter p t
1213735 #-}
1214736
1215737-- | /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.
738+-- dropping characters that fail the predicate @p@ from both the
739+-- beginning and end of @t@. This function is subject to array
740+-- fusion.
1218741dropAround :: (Char -> Bool) -> Text -> Text
1219−dropAround p = dropWhile p . dropWhileEnd p
742+dropAround p = dropWhile p . dropAfter p
1220743{-# INLINE [1] dropAround #-}
1221744
1222745-- | /O(n)/ Remove leading white space from a string. Equivalent to:
1223746--
1224747-- > dropWhile isSpace
1225−stripStart :: Text -> Text
1226−stripStart = dropWhile isSpace
1227−{-# INLINE [1] stripStart #-}
748+stripLeft :: Text -> Text
749+stripLeft = dropWhile isSpace
750+{-# INLINE [1] stripLeft #-}
1228751
1229752-- | /O(n)/ Remove trailing white space from a string. Equivalent to:
1230753--
1231−-- > dropWhileEnd isSpace
1232−stripEnd :: Text -> Text
1233−stripEnd = dropWhileEnd isSpace
1234−{-# INLINE [1] stripEnd #-}
754+-- > dropAfter isSpace
755+stripRight :: Text -> Text
756+stripRight = dropAfter isSpace
757+{-# INLINE [1] stripRight #-}
1235758
1236759-- | /O(n)/ Remove leading and trailing white space from a string.
1237760-- Equivalent to:
@@ -1248,20 +771,28 @@ splitAt :: Int -> Text -> (Text, Text)
1248771splitAt n t@(Text arr off len)
1249772 | n <= 0 = (empty, t)
1250773 | n >= len = (t, empty)
1251− | otherwise = let k = iterN n t
1252− in (text arr off k, text arr (off+k) (len-k))
774+ | otherwise = (Text arr off k, Text arr (off+k) (len-k))
775+ where k = loop 0 0
776+ loop !i !cnt
777+ | i >= len || cnt >= n = i
778+ | otherwise = loop (i+d) (cnt+1)
779+ where d = iter_ t i
780+{-# INLINE splitAt #-}
1253781
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.
782+-- | /O(n)/ 'span', applied to a predicate @p@ and text @t@, returns a
783+-- pair whose first element is the longest prefix (possibly empty) of
784+-- @t@ of elements that satisfy @p@, and whose second is the remainder
785+-- of the list.
1258786span :: (Char -> Bool) -> Text -> (Text, Text)
1259−span p t = case span_ p t of
1260− (# hd,tl #) -> (hd,tl)
787+span p t@(Text arr off len) = (textP arr off k, textP arr (off+k) (len-k))
788+ where k = loop 0
789+ loop !i | i >= len || not (p c) = i
790+ | otherwise = loop (i+d)
791+ where (c,d) = iter t i
1261792{-# INLINE span #-}
1262793
1263−-- | /O(n)/ 'break' is like 'span', but the prefix returned is
1264−-- over elements that fail the predicate @p@.
794+-- | /O(n)/ 'break' is like 'span', but the prefix returned is over
795+-- elements that fail the predicate @p@.
1265796break :: (Char -> Bool) -> Text -> (Text, Text)
1266797break p = span (not . p)
1267798{-# INLINE break #-}
@@ -1273,7 +804,7 @@ groupBy p = loop
1273804 loop t@(Text arr off len)
1274805 | null t = []
1275806 | otherwise = text arr off n : loop (text arr (off+n) (len-n))
1276− where Iter c d = iter t 0
807+ where (c,d) = iter t 0
1277808 n = d + findAIndexOrEnd (not . p c) (Text arr (off+d) (len-d))
1278809
1279810-- | Returns the /array/ index (in units of 'Word16') at which a
@@ -1283,8 +814,8 @@ findAIndexOrEnd :: (Char -> Bool) -> Text -> Int
1283814findAIndexOrEnd q t@(Text _arr _off len) = go 0
1284815 where go !i | i >= len || q c = i
1285816 | otherwise = go (i+d)
1286− where Iter c d = iter t i
1287−
817+ where (c,d) = iter t i
818+
1288819-- | /O(n)/ Group characters in a string by equality.
1289820group :: Text -> [Text]
1290821group = groupBy (==)
@@ -1302,65 +833,100 @@ tails :: Text -> [Text]
1302833tails t | null t = [empty]
1303834 | otherwise = t : tails (unsafeTail t)
1304835
836+-- | /O(n)/ Break a 'Text' into pieces separated by the 'Char'
837+-- argument, consuming the delimiter. I.e.
838+--
839+-- > splitChar '\n' "a\nb\nd\ne" == ["a","b","d","e"]
840+-- > splitChar 'a' "aXaXaXa" == ["","X","X","X",""]
841+-- > splitChar 'x' "x" == ["",""]
842+--
843+-- and
844+--
845+-- > intercalate (singleton c) . splitChar c == id
846+-- > splitChar == splitWith . (==)
847+splitChar :: Char -> Text -> [Text]
848+splitChar c = splitWith (==c)
849+{-# INLINE splitChar #-}
850+
1305851-- $split
1306852--
1307853-- Splitting functions in this library do not perform character-wise
1308854-- copies to create substrings; they just construct new 'Text's that
1309855-- are slices of the original.
1310856
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.
857+-- | /O(m)*O(n)/ Break a 'Text' into pieces separated by the first
858+-- 'Text' argument, consuming the delimiter. Examples:
1314859--
1315−-- Examples:
860+-- > split "\r\n" "a\r\nb\r\nd\r\ne" == ["a","b","d","e"]
861+-- > split "aaa" "aaaXaaaXaaaXaaa" == ["","X","X","X",""]
862+-- > split "x" "x" == ["",""]
863+--
864+-- and
1316865--
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" == ["",""]
866+-- > intercalate s . split s == id
867+split :: Text -- ^ Text to split on
868+ -> Text -- ^ Input text
869+ -> [Text]
870+split pat src0
871+ | l == 0 = [src0]
872+ | otherwise = go src0
873+ where
874+ l = length pat
875+ go src = search 0 src
876+ where
877+ search !n !s
878+ | null s = [src] -- not found
879+ | pat `isPrefixOf` s = take n src : go (drop l s)
880+ | otherwise = search (n+1) (unsafeTail s)
881+{-# INLINE split #-}
882+
883+-- | /O(m)*O(n)/ Break a 'Text' into pieces at most @k@ times,
884+-- treating the first 'Text' argument as the delimiter to break on,
885+-- and consuming the delimiter. The last element of the list contains
886+-- the remaining text after the number of times to split has been
887+-- reached. A value of zero or less for @k@ causes no splitting to
888+-- occur.
1320889--
1321−-- and
890+-- Examples:
1322891--
1323−-- > intercalate s . splitOn s == id
1324−-- > splitOn (singleton c) == split (==c)
892+-- > splitTimes 0 "//" "a//b//c" == ["a//b//c"]
893+-- > splitTimes 2 ":" "a:b:c:d:e" == ["a","b","c:d:e"]
894+-- > splitTimes 100 "???" "a????b" == ["a","?b"]
1325895--
1326−-- (Note: the string @s@ to split on above cannot be empty.)
896+-- and
1327897--
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)
898+-- > intercalate s . splitTimes k s == id
899+splitTimes :: Int -- ^ Maximum number of times to split
900+ -> Text -- ^ Text to split on
901+ -> Text -- ^ Input text
902+ -> [Text]
903+splitTimes k pat src0
904+ | k <= 0 || l == 0 = [src0]
905+ | otherwise = go k src0
1340906 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− #-}
907+ l = length pat
908+ go !i src = search 0 src
909+ where
910+ search !n !s
911+ | i == 0 || null s = [src] -- not found or limit reached
912+ | pat `isPrefixOf` s = take n src : go (i-1) (drop l s)
913+ | otherwise = search (n+1) (unsafeTail s)
914+{-# INLINE splitTimes #-}
1349915
1350916-- | /O(n)/ Splits a 'Text' into components delimited by separators,
1351917-- where the predicate returns True for a separator element. The
1352918-- resulting components do not contain the separators. Two adjacent
1353919-- separators result in an empty component in the output. eg.
1354920--
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
921+-- > splitWith (=='a') "aabbaca" == ["","","bb","c",""]
922+-- > splitWith (=='a') [] == []
923+splitWith :: (Char -> Bool) -> Text -> [Text]
924+splitWith _ (Text _off _arr 0) = []
925+splitWith p t = loop t
1360926 where loop s | null s' = [l]
1361927 | otherwise = l : loop (unsafeTail s')
1362− where (# l, s' #) = span_ (not . p) s
1363−{-# INLINE split #-}
928+ where (l, s') = break p s
929+{-# INLINE splitWith #-}
1364930
1365931-- | /O(n)/ Splits a 'Text' into components of length @k@. The last
1366932-- element may be shorter than the other chunks, depending on the
@@ -1379,14 +945,22 @@ chunksOf k = go
1379945-- ----------------------------------------------------------------------------
1380946-- * Searching
1381947
948+-------------------------------------------------------------------------------
949+-- ** Searching by equality
950+
951+-- | /O(n)/ 'elem' is the 'Text' membership predicate.
952+elem :: Char -> Text -> Bool
953+elem c t = S.elem c (stream t)
954+{-# INLINE elem #-}
955+
1382956-------------------------------------------------------------------------------
1383957-- ** Searching with a predicate
1384958
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.
959+-- | /O(n)/ The 'find' function takes a predicate and a 'Text',
960+-- and returns the first element in matching the predicate, or 'Nothing'
961+-- if there is no such element.
1388962find :: (Char -> Bool) -> Text -> Maybe Char
1389−find p t = S.findBy p (stream t)
963+find p t = S.find p (stream t)
1390964{-# INLINE find #-}
1391965
1392966-- | /O(n)/ The 'partition' function takes a predicate and a 'Text',
@@ -1405,96 +979,10 @@ filter :: (Char -> Bool) -> Text -> Text
1405979filter p t = unstream (S.filter p (stream t))
1406980{-# INLINE filter #-}
1407981
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", "")
1417−--
1418−-- Laws:
1419−--
1420−-- > append prefix match == haystack
1421−-- > where (prefix, match) = breakOn needle haystack
1422−--
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.
1426−--
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.
1439−--
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.
1443−--
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:
1452−--
1453−-- * The entire string prior to the /k/th match (i.e. the prefix)
1454−--
1455−-- * The /k/th match, followed by the remainder of the string
1456−--
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)
1474− where
1475− step x = (chunk 0 x, chunk x (slen-x))
1476− chunk !n !l = text arr (n+off) l
1477−{-# INLINE breakOnAll #-}
1478982
1479983-------------------------------------------------------------------------------
1480984-- ** Indexing 'Text's
1481985
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−
1498986-- | /O(n)/ 'Text' index (subscript) operator, starting from 0.
1499987index :: Text -> Int -> Char
1500988index t n = S.index (stream t) n
@@ -1502,34 +990,39 @@ index t n = S.index (stream t) n
1502990
1503991-- | /O(n)/ The 'findIndex' function takes a predicate and a 'Text'
1504992-- and returns the index of the first element in the 'Text' satisfying
1505−-- the predicate. Subject to fusion.
993+-- the predicate. This function is subject to fusion.
1506994findIndex :: (Char -> Bool) -> Text -> Maybe Int
1507995findIndex p t = S.findIndex p (stream t)
1508996{-# INLINE findIndex #-}
1509997
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 #-}
998+-- | The 'findIndices' function extends 'findIndex', by returning the
999+-- indices of all elements satisfying the predicate, in ascending
1000+-- order. This function is subject to fusion.
1001+findIndices :: (Char -> Bool) -> Text -> [Int]
1002+findIndices p t = S.findIndices p (stream t)
1003+{-# INLINE findIndices #-}
15221004
1523−{-# RULES
1524−"TEXT count/singleton -> countChar" [~1] forall c t.
1525− count (singleton c) t = countChar c t
1526− #-}
1527−
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 #-}
1005+-- | /O(n)/ The 'elemIndex' function returns the index of the first
1006+-- element in the given 'Text' which is equal to the query element, or
1007+-- 'Nothing' if there is no such element. This function is subject to
1008+-- fusion.
1009+elemIndex :: Char -> Text -> Maybe Int
1010+elemIndex c t = S.elemIndex c (stream t)
1011+{-# INLINE elemIndex #-}
1012+
1013+-- | /O(n)/ The 'elemIndices' function returns the index of every
1014+-- element in the given 'Text' which is equal to the query
1015+-- element. This function is subject to fusion.
1016+elemIndices :: Char -> Text -> [Int]
1017+elemIndices c t = S.elemIndices c (stream t)
1018+{-# INLINE elemIndices #-}
1019+
1020+-- | /O(n)/ The 'count' function returns the number of times the query
1021+-- element appears in the given 'Text'. This function is subject to
1022+-- fusion.
1023+count :: Char -> Text -> Int
1024+count c t = S.count c (stream t)
1025+{-# INLINE count #-}
15331026
15341027-------------------------------------------------------------------------------
15351028-- * Zipping
@@ -1540,15 +1033,13 @@ countChar c t = S.countChar c (stream t)
15401033-- equivalent to a pair of 'unpack' operations.
15411034zip :: Text -> Text -> [(Char,Char)]
15421035zip a b = S.unstreamList $ S.zipWith (,) (stream a) (stream b)
1543−{-# INLINE zip #-}
1036+{-# INLINE [0] zip #-}
15441037
15451038-- | /O(n)/ 'zipWith' generalises 'zip' by zipping with the function
15461039-- given as the first argument, instead of a tupling function.
1547−-- Performs replacement on invalid scalar values.
15481040zipWith :: (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 #-}
1041+zipWith f t1 t2 = unstream (S.zipWith f (stream t1) (stream t2))
1042+{-# INLINE [0] zipWith #-}
15521043
15531044-- | /O(n)/ Breaks a 'Text' up into a list of words, delimited by 'Char's
15541045-- representing white space.
@@ -1564,7 +1055,7 @@ words t@(Text arr off len) = loop 0 0
15641055 then loop (start+1) (start+1)
15651056 else Text arr (start+off) (n-start) : loop (n+d) (n+d)
15661057 | otherwise = loop start (n+d)
1567− where Iter c d = iter t n
1058+ where (c,d) = iter t n
15681059{-# INLINE words #-}
15691060
15701061-- | /O(n)/ Breaks a 'Text' up into a list of 'Text's at
@@ -1574,10 +1065,9 @@ lines ps | null ps = []
15741065 | otherwise = h : if null t
15751066 then []
15761067 else lines (unsafeTail t)
1577− where (# h,t #) = span_ (/= '\n') ps
1068+ where (h,t) = span (/= '\n') ps
15781069{-# INLINE lines #-}
15791070
1580−{-
15811071-- | /O(n)/ Portably breaks a 'Text' up into a list of 'Text's at line
15821072-- boundaries.
15831073--
@@ -1585,6 +1075,7 @@ lines ps | null ps = []
15851075-- return immediately followed by a line feed, or a carriage return.
15861076-- This accounts for both Unix and Windows line ending conventions,
15871077-- and for the old convention used on Mac OS 9 and earlier.
1078+{-
15881079lines' :: Text -> [Text]
15891080lines' ps | null ps = []
15901081 | otherwise = h : case uncons t of
@@ -1611,7 +1102,8 @@ unwords = intercalate (singleton ' ')
16111102{-# INLINE unwords #-}
16121103
16131104-- | /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.
1105+-- 'True' iff the first is a prefix of the second. This function is
1106+-- subject to fusion.
16151107isPrefixOf :: Text -> Text -> Bool
16161108isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) =
16171109 alen <= blen && S.isPrefixOf (stream a) (stream b)
@@ -1620,6 +1112,8 @@ isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) =
16201112{-# RULES
16211113"TEXT isPrefixOf -> fused" [~1] forall s t.
16221114 isPrefixOf s t = S.isPrefixOf (stream s) (stream t)
1115+"TEXT isPrefixOf -> unfused" [1] forall s t.
1116+ S.isPrefixOf (stream s) (stream t) = isPrefixOf s t
16231117 #-}
16241118
16251119-- | /O(n)/ The 'isSuffixOf' function takes two 'Text's and returns
@@ -1632,124 +1126,13 @@ isSuffixOf a@(Text _aarr _aoff alen) b@(Text barr boff blen) =
16321126 | otherwise = Text barr (boff+d) alen
16331127{-# INLINE isSuffixOf #-}
16341128
1635−-- | /O(n+m)/ The 'isInfixOf' function takes two 'Text's and returns
1129+-- | /O(n)/ The 'isInfixOf' function takes two 'Text's and returns
16361130-- 'True' iff the first is contained, wholly and intact, anywhere
16371131-- within the second.
1638−--
1639−-- In (unlikely) bad cases, this function's time complexity degrades
1640−-- towards /O(n*m)/.
16411132isInfixOf :: 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
1133+isInfixOf needle haystack = L.any (isPrefixOf needle) (tails haystack)
1134+{-# INLINE isInfixOf #-}
1135+-- TODO: a better implementation
17331136
17341137emptyError :: 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
1138+emptyError fun = P.error ("Data.Text." ++ fun ++ ": empty input")