@@ -1,29 +1,48 @@
1−{-# LANGUAGE BangPatterns #-}
1+{-# LANGUAGE BangPatterns, CPP, MagicHash, Rank2Types, UnboxedTuples #-}
2{-# OPTIONS_GHC -fno-warn-orphans #-}
2{-# OPTIONS_GHC -fno-warn-orphans #-}
3+#if __GLASGOW_HASKELL__ >= 702
4+{-# LANGUAGE Trustworthy #-}
6+#if __GLASGOW_HASKELL__ >= 708
7+{-# LANGUAGE TypeFamilies #-}
5-- Module : Data.Text
11-- Module : Data.Text
6−-- Copyright : (c) Tom Harper 2008-2009,
7−-- (c) Bryan O'Sullivan 2009,
12+-- Copyright : (c) 2009, 2010, 2011, 2012 Bryan O'Sullivan,
8−-- (c) Duncan Coutts 2009
13+-- (c) 2009 Duncan Coutts,
14+-- (c) 2008, 2009 Tom Harper
10-- License : BSD-style
16-- License : BSD-style
11−-- Maintainer : rtharper@aftereternity.co.uk, bos@serpentine.com,
17+-- Maintainer : bos@serpentine.com
13-- Stability : experimental
18-- Stability : experimental
14-- Portability : GHC
19-- Portability : GHC
16−-- A time and space-efficient implementation of Unicode text using
21+-- A time and space-efficient implementation of Unicode text.
17−-- packed Word16 arrays. Suitable for performance critical use, both
22+-- Suitable for performance critical use, both in terms of large data
18−-- in terms of large data quantities and high speed.
23+-- quantities and high speed.
25+-- /Note/: Read below the synopsis for important notes on the use of
20-- This module is intended to be imported @qualified@, to avoid name
28-- This module is intended to be imported @qualified@, to avoid name
21-- clashes with "Prelude" functions, e.g.
29-- clashes with "Prelude" functions, e.g.
23-- > import qualified Data.Text as T
31-- > import qualified Data.Text as T
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 >.
25module Data.Text
38module Data.Text
40+ -- * Strict vs lazy types
27 -- * Fusion
46 -- * Fusion
28 -- $fusion
47 -- $fusion
@@ -47,6 +66,7 @@ module Data.Text
51 -- * Transformations
71 -- * Transformations
@@ -54,6 +74,19 @@ module Data.Text
54 , intersperse
74 , intersperse
55 , transpose
75 , transpose
79+ -- ** Case conversion
58 -- * Folds
91 -- * Folds
@@ -92,21 +125,32 @@ module Data.Text
93 -- ** Breaking strings
126 -- ** Breaking strings
96 , takeWhile
131 , takeWhile
97 , dropWhile
133 , dropWhile
98 , splitAt
139 , splitAt
102 , groupBy
145 , groupBy
106 -- ** Breaking into many substrings
149 -- ** Breaking into many substrings
108− , splitWith
153+ , chunksOf
111 -- ** Breaking into lines and words
155 -- ** Breaking into lines and words
@@ -120,136 +164,309 @@ module Data.Text
120 , isSuffixOf
164 , isSuffixOf
121 , isInfixOf
165 , isInfixOf
123 -- * Searching
172 -- * Searching
127 , partition
176 , partition
129 -- , findSubstring
178 -- , findSubstring
131 -- * Indexing
180 -- * Indexing
133 , findIndex
183 , findIndex
139− -- * Zipping and unzipping
186+ -- * Zipping
140 , zipWith
188 , zipWith
142 -- -* Ordered text
190 -- -* Ordered text
143 -- , sort
191 -- , sort
193+ -- * Low level operations
146−import Prelude (Char, Bool(..), Functor(..), Int, Maybe(..), String,
198+import Prelude (Char, Bool(..), Int, Maybe(..), String,
147− Eq(..), Ord(..), (++),
199+ Eq(..), Ord(..), Ordering(..), (++),
148− Read(..), Show(..),
200+ Read(..),
149− (&&), (||), (+), (-), (.), ($),
201+ (&&), (||), (+), (-), (.), ($), ($!), (>>),
150− not, return, otherwise)
202+ not, return, otherwise, quot)
203+#if defined(HAVE_DEEPSEQ)
204+import Control.DeepSeq (NFData(rnf))
151import Control.Exception (assert)
207import Control.Exception (assert)
152import Data.Char (isSpace)
209import 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)
153import Control.Monad.ST (ST)
213import Control.Monad.ST (ST)
154import qualified Data.Text.Array as A
214import qualified Data.Text.Array as A
155import qualified Data.List as L
215import qualified Data.List as L
216+import Data.Binary (Binary(get, put))
156import Data.Monoid (Monoid(..))
217import Data.Monoid (Monoid(..))
218+#if MIN_VERSION_base(4,9,0)
157−import Data.Word (Word16)
219+import Data.Semigroup (Semigroup(..))
158import Data.String (IsString(..))
221import Data.String (IsString(..))
160−import qualified Data.Text.Fusion as S
222+import qualified Data.Text.Internal.Fusion as S
161−import qualified Data.Text.Fusion.Common as S
223+import qualified Data.Text.Internal.Fusion.Common as S
224+import Data.Text.Encoding (decodeUtf8', encodeUtf8)
162−import Data.Text.Fusion (stream, reverseStream, unstream)
225+import Data.Text.Internal.Fusion (stream, reverseStream, unstream)
163−
226+import Data.Text.Internal.Private (span_)
164−import Data.Text.Internal (Text(..), empty, text, textP)
227+import Data.Text.Internal (Text(..), empty, firstf, mul, safe, text)
228+import Data.Text.Show (singleton, unpack, unpackCString#)
165import qualified Prelude as P
229import qualified Prelude as P
166−import Data.Text.Unsafe (iter, iter_, unsafeHead, unsafeTail)
230+import Data.Text.Unsafe (Iter(..), iter, iter_, lengthWord16, reverseIter,
231+ reverseIter_, unsafeHead, unsafeTail)
167−import Data.Text.UnsafeChar (unsafeChr)
232+import Data.Text.Internal.Unsafe.Char (unsafeChr)
168−import qualified Data.Text.Encoding.Utf16 as U16
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)
241+import GHC.Base (eqInt, neInt, gtInt, geInt, ltInt, leInt)
242+#if __GLASGOW_HASKELL__ >= 708
243+import qualified GHC.Exts as Exts
245+#if MIN_VERSION_base(4,7,0)
246+import Text.Printf (PrintfArg, formatArg, formatString)
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.
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.
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'
272+-- A 'Text' value is a sequence of Unicode scalar values, as defined
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
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
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\".
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 >.)
170-- $fusion
299-- $fusion
172−-- Most of the functions in this module are subject to /array fusion/,
301+-- Most of the functions in this module are subject to /fusion/,
173−-- meaning that a pipeline of functions will usually allocate at most
302+-- meaning that a pipeline of such functions will usually allocate at
174−-- one 'Text' value.
303+-- most one 'Text' value.
305+-- As an example, consider the following pipeline:
307+-- > import Data.Text as T
308+-- > import Data.Text.Encoding as E
309+-- > import Data.ByteString (ByteString)
311+-- > countChars :: ByteString -> Int
312+-- > countChars = T.length . T.toUpper . E.decodeUtf8
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'.
321+-- Functions that can be fused by the compiler are documented with the
322+-- phrase \"Subject to fusion\".
176instance Eq Text where
324instance Eq Text where
177− t1 == t2 = stream t1 == stream t2
325+ Text arrA offA lenA == Text arrB offB lenB
326+ | lenA == lenB = A.equal arrA offA arrB offB lenA
178 {-# INLINE (==) #-}
328 {-# INLINE (==) #-}
180instance Ord Text where
330instance Ord Text where
181− compare t1 t2 = compare (stream t1) (stream t2)
331+ compare = compareText
182− {-# INLINE compare #-}
184−instance Show Text where
185− showsPrec p ps r = showsPrec p (unpack ps) r
187instance Read Text where
333instance Read Text where
188 readsPrec p str = [(pack x,y) | (x,y) <- readsPrec p str]
334 readsPrec p str = [(pack x,y) | (x,y) <- readsPrec p str]
336+#if MIN_VERSION_base(4,9,0)
337+-- Semigroup orphan instances for older GHCs are provided by
338+-- 'semigroups` package
340+instance Semigroup Text where
190instance Monoid Text where
344instance Monoid Text where
191 mempty = empty
345 mempty = empty
346+#if MIN_VERSION_base(4,9,0)
347+ mappend = (<>) -- future-proof definition
192 mappend = append
349 mappend = append
193 mconcat = concat
351 mconcat = concat
195instance IsString Text where
353instance IsString Text where
196 fromString = pack
354 fromString = pack
356+#if __GLASGOW_HASKELL__ >= 708
357+instance Exts.IsList Text where
358+ type Item Text = Char
363+#if defined(HAVE_DEEPSEQ)
364+instance NFData Text where rnf !_ = ()
367+instance Binary Text where
368+ put t = put (encodeUtf8 t)
371+ case decodeUtf8' bs of
372+ P.Left exn -> P.fail (P.show exn)
373+ P.Right a -> P.return a
375+-- | This instance preserves data abstraction at the cost of inefficiency.
376+-- We omit reflection services for the sake of data abstraction.
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
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? >
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, ... >
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
395+ _ -> P.error "gunfold"
396+ dataTypeOf _ = textDataType
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
405+packConstr = mkConstr textDataType "pack" [] Prefix
407+textDataType :: DataType
408+textDataType = mkDataType "Data.Text.Text" [packConstr]
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
417+ | i >= lenA || j >= lenB = compare lenA lenB
420+ | otherwise = go (i+di) (j+dj)
421+ where Iter a di = iter ta i
422+ Iter b dj = iter tb j
198-- -----------------------------------------------------------------------------
424-- -----------------------------------------------------------------------------
199-- * Conversion to/from 'Text'
425-- * Conversion to/from 'Text'
201−-- | /O(n)/ Convert a 'String' into a 'Text'.
427+-- | /O(n)/ Convert a 'String' into a 'Text'. Subject to
202−--
428+-- fusion. Performs replacement on invalid scalar values.
203−-- This function is subject to array fusion.
204pack :: String -> Text
429pack :: String -> Text
205−pack = unstream . S.streamList
430+pack = unstream . S.map safe . S.streamList
206{-# INLINE [1] pack #-}
431{-# INLINE [1] pack #-}
208−-- | /O(n)/ Convert a Text into a String.
209−-- Subject to array fusion.
210−unpack :: Text -> String
211−unpack = S.unstreamList . stream
212−{-# INLINE [1] unpack #-}
214−-- | /O(1)/ Convert a character into a Text.
215−-- Subject to array fusion.
216−singleton :: Char -> Text
217−singleton = unstream . S.singleton
218−{-# INLINE [1] singleton #-}
220-- -----------------------------------------------------------------------------
433-- -----------------------------------------------------------------------------
221-- * Basic functions
434-- * Basic functions
223-- | /O(n)/ Adds a character to the front of a 'Text'. This function
436-- | /O(n)/ Adds a character to the front of a 'Text'. This function
224-- is more costly than its 'List' counterpart because it requires
437-- is more costly than its 'List' counterpart because it requires
225−-- copying a new array. Subject to array fusion.
438+-- copying a new array. Subject to fusion. Performs replacement on
439+-- invalid scalar values.
226cons :: Char -> Text -> Text
440cons :: Char -> Text -> Text
227−cons c t = unstream (S.cons c (stream t))
441+cons c t = unstream (S.cons (safe c) (stream t))
228{-# INLINE cons #-}
442{-# INLINE cons #-}
230-- | /O(n)/ Adds a character to the end of a 'Text'. This copies the
446-- | /O(n)/ Adds a character to the end of a 'Text'. This copies the
231−-- entire array in the process. Subject to array fusion.
447+-- entire array in the process, unless fused. Subject to fusion.
448+-- Performs replacement on invalid scalar values.
232snoc :: Text -> Char -> Text
449snoc :: Text -> Char -> Text
233−snoc t c = unstream (S.snoc (stream t) c)
450+snoc t c = unstream (S.snoc (stream t) (safe c))
234{-# INLINE snoc #-}
451{-# INLINE snoc #-}
236-- | /O(n)/ Appends one 'Text' to the other by copying both of them
453-- | /O(n)/ Appends one 'Text' to the other by copying both of them
237−-- into a new 'Text'. Subject to array fusion.
454+-- into a new 'Text'. Subject to fusion.
238append :: Text -> Text -> Text
455append :: Text -> Text -> Text
239−append (Text arr1 off1 len1) (Text arr2 off2 len2) = Text (A.run x) 0 len
456+append a@(Text arr1 off1 len1) b@(Text arr2 off2 len2)
459+ | len > 0 = Text (A.run x) 0 len
460+ | otherwise = overflowError "append"
241 len = len1+len2
462 len = len1+len2
463+ x :: ST s (A.MArray s)
243− arr <- A.unsafeNew len :: ST s (A.MArray s Word16)
465+ arr <- A.new len
244− copy arr1 off1 (len1+off1) arr 0
466+ A.copyI arr 0 arr1 off1 len1
245− copy arr2 off2 (len2+off2) arr len1
467+ A.copyI arr len1 arr2 off2 len
246 return arr
468 return arr
248− copy arr i top arr' j
249− | i >= top = return ()
250− | otherwise = do A.unsafeWrite arr' j (arr `A.unsafeIndex` i)
251− copy arr (i+1) top arr' (j+1)
252−{-# INLINE append #-}
469+{-# NOINLINE append #-}
255"TEXT append -> fused" [~1] forall t1 t2.
472"TEXT append -> fused" [~1] forall t1 t2.
@@ -259,33 +476,26 @@ append (Text arr1 off1 len1) (Text arr2 off2 len2) = Text (A.run x) 0 len
261-- | /O(1)/ Returns the first character of a 'Text', which must be
478-- | /O(1)/ Returns the first character of a 'Text', which must be
262−-- non-empty. Subject to array fusion.
479+-- non-empty. Subject to fusion.
263head :: Text -> Char
480head :: Text -> Char
264head t = S.head (stream t)
481head t = S.head (stream t)
265{-# INLINE head #-}
482{-# INLINE head #-}
267-- | /O(1)/ Returns the first character and rest of a 'Text', or
484-- | /O(1)/ Returns the first character and rest of a 'Text', or
268−-- 'Nothing' if empty. Subject to array fusion.
485+-- 'Nothing' if empty. Subject to fusion.
269uncons :: Text -> Maybe (Char, Text)
486uncons :: Text -> Maybe (Char, Text)
270uncons t@(Text arr off len)
487uncons t@(Text arr off len)
271 | len <= 0 = Nothing
488 | len <= 0 = Nothing
489+ | otherwise = Just $ let !(Iter c d) = iter t 0
272− | otherwise = Just (c, textP arr (off+d) (len-d))
490+ in (c, text arr (off+d) (len-d))
273− where (c,d) = iter t 0
274−{-# INLINE uncons #-}
491+{-# INLINE [1] uncons #-}
276-- | Lifted from Control.Arrow and specialized.
493-- | Lifted from Control.Arrow and specialized.
277second :: (b -> c) -> (a,b) -> (a,c)
494second :: (b -> c) -> (a,b) -> (a,c)
278second f (a, b) = (a, f b)
495second f (a, b) = (a, f b)
281−"TEXT uncons -> fused" [~1] forall t.
282− uncons t = fmap (second unstream) (S.uncons (stream t))
283−"TEXT uncons -> unfused" [1] forall t.
284− fmap (second unstream) (S.uncons (stream t)) = uncons t
287-- | /O(1)/ Returns the last character of a 'Text', which must be
497-- | /O(1)/ Returns the last character of a 'Text', which must be
288−-- non-empty. Subject to array fusion.
498+-- non-empty. Subject to fusion.
289last :: Text -> Char
499last :: Text -> Char
290last (Text arr off len)
500last (Text arr off len)
291 | len <= 0 = emptyError "last"
501 | len <= 0 = emptyError "last"
@@ -303,11 +513,11 @@ last (Text arr off len)
305-- | /O(1)/ Returns all characters after the head of a 'Text', which
515-- | /O(1)/ Returns all characters after the head of a 'Text', which
306−-- must be non-empty. Subject to array fusion.
516+-- must be non-empty. Subject to fusion.
307tail :: Text -> Text
517tail :: Text -> Text
308tail t@(Text arr off len)
518tail t@(Text arr off len)
309 | len <= 0 = emptyError "tail"
519 | len <= 0 = emptyError "tail"
310− | otherwise = textP arr (off+d) (len-d)
520+ | otherwise = text arr (off+d) (len-d)
311 where d = iter_ t 0
521 where d = iter_ t 0
312{-# INLINE [1] tail #-}
522{-# INLINE [1] tail #-}
@@ -319,11 +529,11 @@ tail t@(Text arr off len)
321-- | /O(1)/ Returns all but the last character of a 'Text', which must
531-- | /O(1)/ Returns all but the last character of a 'Text', which must
322−-- be non-empty. Subject to array fusion.
532+-- be non-empty. Subject to fusion.
323init :: Text -> Text
533init :: Text -> Text
324init (Text arr off len) | len <= 0 = emptyError "init"
534init (Text arr off len) | len <= 0 = emptyError "init"
325− | n >= 0xDC00 && n <= 0xDFFF = textP arr off (len-2)
535+ | n >= 0xDC00 && n <= 0xDFFF = text arr off (len-2)
326− | otherwise = textP arr off (len-1)
536+ | otherwise = text arr off (len-1)
328 n = A.unsafeIndex arr (off+len-1)
538 n = A.unsafeIndex arr (off+len-1)
329{-# INLINE [1] init #-}
539{-# INLINE [1] init #-}
@@ -335,10 +545,14 @@ init (Text arr off len) | len <= 0 = emptyError "init"
335 unstream (S.init (stream t)) = init t
545 unstream (S.init (stream t)) = init t
338−-- | /O(1)/ Tests whether a 'Text' is empty or not. Subject to array
548+-- | /O(1)/ Tests whether a 'Text' is empty or not. Subject to
339-- fusion.
549-- fusion.
340null :: Text -> Bool
550null :: Text -> Bool
341−null (Text _arr _off len) = assert (len >= 0) $ len <= 0
551+null (Text _arr _off len) =
342{-# INLINE [1] null #-}
556{-# INLINE [1] null #-}
@@ -348,38 +562,284 @@ null (Text _arr _off len) = assert (len >= 0) $ len <= 0
348 S.null (stream t) = null t
562 S.null (stream t) = null t
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 #-}
351-- | /O(n)/ Returns the number of characters in a 'Text'.
571-- | /O(n)/ Returns the number of characters in a 'Text'.
352−-- Subject to array fusion.
572+-- Subject to fusion.
353length :: Text -> Int
573length :: Text -> Int
354length t = S.length (stream t)
574length t = S.length (stream t)
355−{-# INLINE length #-}
575+{-# INLINE [0] length #-}
576+-- length needs to be phased after the compareN/length rules otherwise
577+-- it may inline before the rules have an opportunity to fire.
579+-- | /O(n)/ Compare the count of characters in a 'Text' to a number.
580+-- Subject to fusion.
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 #-}
590+"TEXT compareN/length -> compareLength" [~1] forall t n.
591+ compare (length t) n = compareLength t n
595+"TEXT ==N/length -> compareLength/==EQ" [~1] forall t n.
596+ eqInt (length t) n = compareLength t n == EQ
600+"TEXT /=N/length -> compareLength//=EQ" [~1] forall t n.
601+ neInt (length t) n = compareLength t n /= EQ
605+"TEXT <N/length -> compareLength/==LT" [~1] forall t n.
606+ ltInt (length t) n = compareLength t n == LT
610+"TEXT <=N/length -> compareLength//=GT" [~1] forall t n.
611+ leInt (length t) n = compareLength t n /= GT
615+"TEXT >N/length -> compareLength/==GT" [~1] forall t n.
616+ gtInt (length t) n = compareLength t n == GT
620+"TEXT >=N/length -> compareLength//=LT" [~1] forall t n.
621+ geInt (length t) n = compareLength t n /= LT
357-- -----------------------------------------------------------------------------
624-- -----------------------------------------------------------------------------
358-- * Transformations
625-- * Transformations
359−-- | /O(n)/ 'map' @f @xs is the 'Text' obtained by applying @f@ to
626+-- | /O(n)/ 'map' @f@ @t@ is the 'Text' obtained by applying @f@ to
360−-- each element of @xs@. Subject to array fusion.
627+-- each element of @t@. Subject to fusion. Performs replacement on
628+-- invalid scalar values.
361map :: (Char -> Char) -> Text -> Text
629map :: (Char -> Char) -> Text -> Text
362−map f t = unstream (S.map f (stream t))
630+map f t = unstream (S.map (safe . f) (stream t))
363{-# INLINE [1] map #-}
631{-# INLINE [1] map #-}
365-- | /O(n)/ The 'intercalate' function takes a 'Text' and a list of
633-- | /O(n)/ The 'intercalate' function takes a 'Text' and a list of
366-- 'Text's and concatenates the list after interspersing the first
634-- 'Text's and concatenates the list after interspersing the first
367-- argument between each element of the list.
635-- argument between each element of the list.
368intercalate :: Text -> [Text] -> Text
636intercalate :: Text -> [Text] -> Text
369−intercalate t ts = unstream (S.intercalate (stream t) (L.map stream ts))
637+intercalate t = concat . (F.intersperse t)
370{-# INLINE intercalate #-}
638{-# INLINE intercalate #-}
372-- | /O(n)/ The 'intersperse' function takes a character and places it
640-- | /O(n)/ The 'intersperse' function takes a character and places it
373−-- between the characters of a 'Text'. Subject to array fusion.
641+-- between the characters of a 'Text'. Subject to fusion. Performs
642+-- replacement on invalid scalar values.
374intersperse :: Char -> Text -> Text
643intersperse :: Char -> Text -> Text
375−intersperse c t = unstream (S.intersperse c (stream t))
644+intersperse c t = unstream (S.intersperse (safe c) (stream t))
376{-# INLINE intersperse #-}
645{-# INLINE intersperse #-}
378−-- | /O(n)/ Reverse the characters of a string. Subject to array fusion.
647+-- | /O(n)/ Reverse the characters of a string. Subject to fusion.
379reverse :: Text -> Text
648reverse :: Text -> Text
380reverse t = S.reverse (stream t)
649reverse t = S.reverse (stream t)
381{-# INLINE reverse #-}
650{-# INLINE reverse #-}
652+-- | /O(m+n)/ Replace every non-overlapping occurrence of @needle@ in
653+-- @haystack@ with @replacement@.
655+-- This function behaves as though it was defined as follows:
658+-- replace needle replacement haystack =
659+-- 'intercalate' replacement ('splitOn' needle haystack)
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:
666+-- > replace "oo" "foo" "oo" == "foo"
668+-- In cases where several instances of @needle@ overlap, only the
669+-- first one will be replaced:
671+-- > replace "ofo" "bar" "ofofo" == "barfo"
673+-- In (unlikely) bad cases, this function's time complexity degrades
676+ -- ^ @needle@ to search for. If this string is empty, an
677+ -- error will occur.
679+ -- ^ @replacement@ to replace @needle@ with.
681+ -- ^ @haystack@ in which to search.
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
691+ ixs = indices needle haystack
692+ len = hayLen - (neeLen - repLen) `mul` L.length ixs
693+ x :: ST s (A.MArray s)
696+ let loop (i:is) o d = do
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
706+-- ----------------------------------------------------------------------------
707+-- ** Case conversions (folds)
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.
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 >.
726+-- | /O(n)/ Convert a string to folded case. Subject to fusion.
728+-- This function is mainly useful for performing caseless (also known
729+-- as case insensitive) string comparisons.
731+-- A string @x@ is a caseless match for a string @y@ if and only if:
733+-- @toCaseFold x == toCaseFold y@
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 #-}
746+-- | /O(n)/ Convert a string to lower case, using simple case
747+-- conversion. Subject to fusion.
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 #-}
757+-- | /O(n)/ Convert a string to upper case, using simple case
758+-- conversion. Subject to fusion.
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\".
763+toUpper :: Text -> Text
764+toUpper t = unstream (S.toUpper (stream t))
765+{-# INLINE toUpper #-}
767+-- | /O(n)/ Convert a string to title case, using simple case
768+-- conversion. Subject to fusion.
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
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).
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 #-}
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.
795+-- > justifyLeft 7 'x' "foo" == "fooxxxx"
796+-- > justifyLeft 3 'x' "foobar" == "foobar"
797+justifyLeft :: Int -> Char -> Text -> Text
800+ | otherwise = t `append` replicateChar (k-len) c
801+ where len = length t
802+{-# INLINE [1] justifyLeft #-}
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
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.
817+-- > justifyRight 7 'x' "bar" == "xxxxbar"
818+-- > justifyRight 3 'x' "foobar" == "foobar"
819+justifyRight :: Int -> Char -> Text -> Text
822+ | otherwise = replicateChar (k-len) c `append` t
823+ where len = length t
824+{-# INLINE justifyRight #-}
826+-- | /O(n)/ Center a string to the given length, using the specified
827+-- fill character on either side. Performs replacement on invalid
832+-- > center 8 'x' "HS" = "xxxHSxxx"
833+center :: Int -> Char -> Text -> Text
836+ | otherwise = replicateChar l c `append` t `append` replicateChar r c
837+ where len = length t
841+{-# INLINE center #-}
383-- | /O(n)/ The 'transpose' function transposes the rows and columns
843-- | /O(n)/ The 'transpose' function transposes the rows and columns
384-- of its 'Text' argument. Note that this function uses 'pack',
844-- of its 'Text' argument. Note that this function uses 'pack',
385-- 'unpack', and the list version of transpose, and is thus not very
845-- 'unpack', and the list version of transpose, and is thus not very
@@ -393,26 +853,23 @@ transpose ts = P.map pack (L.transpose (P.map unpack ts))
393-- | /O(n)/ 'foldl', applied to a binary operator, a starting value
853-- | /O(n)/ 'foldl', applied to a binary operator, a starting value
394-- (typically the left-identity of the operator), and a 'Text',
854-- (typically the left-identity of the operator), and a 'Text',
395-- reduces the 'Text' using the binary operator, from left to right.
855-- reduces the 'Text' using the binary operator, from left to right.
396−-- Subject to array fusion.
856+-- Subject to fusion.
397−foldl :: (b -> Char -> b) -> b -> Text -> b
857+foldl :: (a -> Char -> a) -> a -> Text -> a
398foldl f z t = S.foldl f z (stream t)
858foldl f z t = S.foldl f z (stream t)
399{-# INLINE foldl #-}
859{-# INLINE foldl #-}
401−-- | /O(n)/ A strict version of 'foldl'.
861+-- | /O(n)/ A strict version of 'foldl'. Subject to fusion.
402−-- Subject to array fusion.
403−foldl' :: (b -> Char -> b) -> b -> Text -> b
862+foldl' :: (a -> Char -> a) -> a -> Text -> a
404foldl' f z t = S.foldl' f z (stream t)
863foldl' f z t = S.foldl' f z (stream t)
405{-# INLINE foldl' #-}
864{-# INLINE foldl' #-}
407-- | /O(n)/ A variant of 'foldl' that has no starting value argument,
866-- | /O(n)/ A variant of 'foldl' that has no starting value argument,
408−-- and thus must be applied to a non-empty 'Text'. Subject to array
867+-- and thus must be applied to a non-empty 'Text'. Subject to fusion.
410foldl1 :: (Char -> Char -> Char) -> Text -> Char
868foldl1 :: (Char -> Char -> Char) -> Text -> Char
411foldl1 f t = S.foldl1 f (stream t)
869foldl1 f t = S.foldl1 f (stream t)
412{-# INLINE foldl1 #-}
870{-# INLINE foldl1 #-}
414−-- | /O(n)/ A strict version of 'foldl1'.
872+-- | /O(n)/ A strict version of 'foldl1'. Subject to fusion.
415−-- Subject to array fusion.
416foldl1' :: (Char -> Char -> Char) -> Text -> Char
873foldl1' :: (Char -> Char -> Char) -> Text -> Char
417foldl1' f t = S.foldl1' f (stream t)
874foldl1' f t = S.foldl1' f (stream t)
418{-# INLINE foldl1' #-}
875{-# INLINE foldl1' #-}
@@ -420,13 +877,13 @@ foldl1' f t = S.foldl1' f (stream t)
420-- | /O(n)/ 'foldr', applied to a binary operator, a starting value
877-- | /O(n)/ 'foldr', applied to a binary operator, a starting value
421-- (typically the right-identity of the operator), and a 'Text',
878-- (typically the right-identity of the operator), and a 'Text',
422-- reduces the 'Text' using the binary operator, from right to left.
879-- reduces the 'Text' using the binary operator, from right to left.
423−-- Subject to array fusion.
880+-- Subject to fusion.
424−foldr :: (Char -> b -> b) -> b -> Text -> b
881+foldr :: (Char -> a -> a) -> a -> Text -> a
425foldr f z t = S.foldr f z (stream t)
882foldr f z t = S.foldr f z (stream t)
426{-# INLINE foldr #-}
883{-# INLINE foldr #-}
428−-- | /O(n)/ A variant of 'foldr' that has no starting value argument, and
885+-- | /O(n)/ A variant of 'foldr' that has no starting value argument,
429−-- thust must be applied to a non-empty 'Text'. Subject to array
886+-- and thus must be applied to a non-empty 'Text'. Subject to
430-- fusion.
887-- fusion.
431foldr1 :: (Char -> Char -> Char) -> Text -> Char
888foldr1 :: (Char -> Char -> Char) -> Text -> Char
432foldr1 f t = S.foldr1 f (stream t)
889foldr1 f t = S.foldr1 f (stream t)
@@ -435,40 +892,48 @@ foldr1 f t = S.foldr1 f (stream t)
435-- -----------------------------------------------------------------------------
892-- -----------------------------------------------------------------------------
436-- ** Special folds
893-- ** Special folds
438−-- | /O(n)/ Concatenate a list of 'Text's. Subject to array fusion.
895+-- | /O(n)/ Concatenate a list of 'Text's.
439concat :: [Text] -> Text
896concat :: [Text] -> Text
440−concat ts = unstream (S.concat (L.map stream ts))
897+concat ts = case ts' of
441−{-# INLINE concat #-}
898+ [] -> empty
900+ _ -> Text (A.run go) 0 len
902+ ts' = L.filter (not . null) ts
903+ len = sumP "concat" $ L.map lengthWord16 ts'
904+ go :: ST s (A.MArray s)
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
443-- | /O(n)/ Map a function over a 'Text' that results in a 'Text', and
911-- | /O(n)/ Map a function over a 'Text' that results in a 'Text', and
444−-- concatenate the results. This function is subject to array fusion.
912+-- concatenate the results.
446−-- Note: if in 'concatMap' @f@ @t@, @f@ is defined in terms of fusible
447−-- functions, it will also be fusible.
448concatMap :: (Char -> Text) -> Text -> Text
913concatMap :: (Char -> Text) -> Text -> Text
449−concatMap f t = unstream (S.concatMap (stream . f) (stream t))
914+concatMap f = concat . foldr ((:) . f) []
450{-# INLINE concatMap #-}
915{-# INLINE concatMap #-}
452-- | /O(n)/ 'any' @p@ @t@ determines whether any character in the
917-- | /O(n)/ 'any' @p@ @t@ determines whether any character in the
453−-- 'Text' @t@ satisifes the predicate @p@. Subject to array fusion.
918+-- 'Text' @t@ satisfies the predicate @p@. Subject to fusion.
454any :: (Char -> Bool) -> Text -> Bool
919any :: (Char -> Bool) -> Text -> Bool
455any p t = S.any p (stream t)
920any p t = S.any p (stream t)
456{-# INLINE any #-}
921{-# INLINE any #-}
458-- | /O(n)/ 'all' @p@ @t@ determines whether all characters in the
923-- | /O(n)/ 'all' @p@ @t@ determines whether all characters in the
459−-- 'Text' @t@ satisify the predicate @p@. Subject to array fusion.
924+-- 'Text' @t@ satisfy the predicate @p@. Subject to fusion.
460all :: (Char -> Bool) -> Text -> Bool
925all :: (Char -> Bool) -> Text -> Bool
461all p t = S.all p (stream t)
926all p t = S.all p (stream t)
462{-# INLINE all #-}
927{-# INLINE all #-}
464-- | /O(n)/ 'maximum' returns the maximum value from a 'Text', which
929-- | /O(n)/ 'maximum' returns the maximum value from a 'Text', which
465−-- must be non-empty. Subject to array fusion.
930+-- must be non-empty. Subject to fusion.
466maximum :: Text -> Char
931maximum :: Text -> Char
467maximum t = S.maximum (stream t)
932maximum t = S.maximum (stream t)
468{-# INLINE maximum #-}
933{-# INLINE maximum #-}
470-- | /O(n)/ 'minimum' returns the minimum value from a 'Text', which
935-- | /O(n)/ 'minimum' returns the minimum value from a 'Text', which
471−-- must be non-empty. Subject to array fusion.
936+-- must be non-empty. Subject to fusion.
472minimum :: Text -> Char
937minimum :: Text -> Char
473minimum t = S.minimum (stream t)
938minimum t = S.minimum (stream t)
474{-# INLINE minimum #-}
939{-# INLINE minimum #-}
@@ -477,8 +942,8 @@ minimum t = S.minimum (stream t)
477-- * Building 'Text's
942-- * Building 'Text's
479-- | /O(n)/ 'scanl' is similar to 'foldl', but returns a list of
944-- | /O(n)/ 'scanl' is similar to 'foldl', but returns a list of
480−-- successive reduced values from the left. This function is subject
945+-- successive reduced values from the left. Subject to fusion.
481−-- to array fusion.
946+-- Performs replacement on invalid scalar values.
483-- > scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]
948-- > scanl f z [x1, x2, ...] == [z, z `f` x1, (z `f` x1) `f` x2, ...]
@@ -486,11 +951,13 @@ minimum t = S.minimum (stream t)
487-- > last (scanl f z xs) == foldl f z xs.
952-- > last (scanl f z xs) == foldl f z xs.
488scanl :: (Char -> Char -> Char) -> Char -> Text -> Text
953scanl :: (Char -> Char -> Char) -> Char -> Text -> Text
489−scanl f z t = unstream (S.scanl f z (stream t))
954+scanl f z t = unstream (S.scanl g z (stream t))
955+ where g a b = safe (f a b)
490{-# INLINE scanl #-}
956{-# INLINE scanl #-}
492-- | /O(n)/ 'scanl1' is a variant of 'scanl' that has no starting
958-- | /O(n)/ 'scanl1' is a variant of 'scanl' that has no starting
493−-- value argument. This function is subject to array fusion.
959+-- value argument. Subject to fusion. Performs replacement on
960+-- invalid scalar values.
495-- > scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]
962-- > scanl1 f [x1, x2, ...] == [x1, x1 `f` x2, ...]
496scanl1 :: (Char -> Char -> Char) -> Text -> Text
963scanl1 :: (Char -> Char -> Char) -> Text -> Text
@@ -498,49 +965,75 @@ scanl1 f t | null t = empty
498 | otherwise = scanl f (unsafeHead t) (unsafeTail t)
965 | otherwise = scanl f (unsafeHead t) (unsafeTail t)
499{-# INLINE scanl1 #-}
966{-# INLINE scanl1 #-}
501−-- | /O(n)/ 'scanr' is the right-to-left dual of 'scanl'.
968+-- | /O(n)/ 'scanr' is the right-to-left dual of 'scanl'. Performs
969+-- replacement on invalid scalar values.
503-- > scanr f v == reverse . scanl (flip f) v . reverse
971-- > scanr f v == reverse . scanl (flip f) v . reverse
504scanr :: (Char -> Char -> Char) -> Char -> Text -> Text
972scanr :: (Char -> Char -> Char) -> Char -> Text -> Text
505−scanr f z = S.reverse . S.reverseScanr f z . reverseStream
973+scanr f z = S.reverse . S.reverseScanr g z . reverseStream
974+ where g a b = safe (f a b)
506{-# INLINE scanr #-}
975{-# INLINE scanr #-}
508-- | /O(n)/ 'scanr1' is a variant of 'scanr' that has no starting
977-- | /O(n)/ 'scanr1' is a variant of 'scanr' that has no starting
509−-- value argument. This function is subject to array fusion.
978+-- value argument. Subject to fusion. Performs replacement on
979+-- invalid scalar values.
510scanr1 :: (Char -> Char -> Char) -> Text -> Text
980scanr1 :: (Char -> Char -> Char) -> Text -> Text
511scanr1 f t | null t = empty
981scanr1 f t | null t = empty
512 | otherwise = scanr f (last t) (init t)
982 | otherwise = scanr f (last t) (init t)
513{-# INLINE scanr1 #-}
983{-# INLINE scanr1 #-}
515−-- | /O(n)/ Like a combination of 'map' and 'foldl'. Applies a
985+-- | /O(n)/ Like a combination of 'map' and 'foldl''. Applies a
516-- function to each element of a 'Text', passing an accumulating
986-- function to each element of a 'Text', passing an accumulating
517−-- parameter from left to right, and returns a final 'Text'.
987+-- parameter from left to right, and returns a final 'Text'. Performs
988+-- replacement on invalid scalar values.
518mapAccumL :: (a -> Char -> (a,Char)) -> a -> Text -> (a, Text)
989mapAccumL :: (a -> Char -> (a,Char)) -> a -> Text -> (a, Text)
519−mapAccumL f s t = case uncons t of
990+mapAccumL f z0 = S.mapAccumL g z0 . stream
520− Nothing -> (s, empty)
991+ where g a b = second safe (f a b)
521− Just (x, xs) -> (s'', cons y ys)
522− where (s', y ) = f s x
523− (s'',ys) = mapAccumL f s' xs
992+{-# INLINE mapAccumL #-}
525-- | The 'mapAccumR' function behaves like a combination of 'map' and
994-- | The 'mapAccumR' function behaves like a combination of 'map' and
526−-- 'foldr'; it applies a function to each element of a 'Text', passing
995+-- a strict 'foldr'; it applies a function to each element of a
527−-- an accumulating parameter from right to left, and returning a final
996+-- 'Text', passing an accumulating parameter from right to left, and
528−-- value of this accumulator together with the new 'Text'.
997+-- returning a final value of this accumulator together with the new
999+-- Performs replacement on invalid scalar values.
529mapAccumR :: (a -> Char -> (a,Char)) -> a -> Text -> (a, Text)
1000mapAccumR :: (a -> Char -> (a,Char)) -> a -> Text -> (a, Text)
530−mapAccumR f s t = case uncons t of
1001+mapAccumR f z0 = second reverse . S.mapAccumL g z0 . reverseStream
531− Nothing -> (s, empty)
1002+ where g a b = second safe (f a b)
532− Just (x, xs) -> (s'', cons y ys)
533− where (s'',y ) = f s' x
534− (s', ys) = mapAccumR f s xs
1003+{-# INLINE mapAccumR #-}
536-- -----------------------------------------------------------------------------
1005-- -----------------------------------------------------------------------------
537-- ** Generating and unfolding 'Text's
1006-- ** Generating and unfolding 'Text's
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
1014+ | isSingleton t = replicateChar n (unsafeHead t)
1015+ | otherwise = Text (A.run x) 0 len
1018+ x :: ST s (A.MArray s)
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)
1025+{-# INLINE [1] replicate #-}
1028+"TEXT replicate/singleton -> replicateChar" [~1] forall n c.
1029+ replicate n (singleton c) = replicateChar n c
539−-- | /O(n)/ 'replicate' @n@ @c@ is a 'Text' of length @n@ with @c@ the
1032+-- | /O(n)/ 'replicateChar' @n@ @c@ is a 'Text' of length @n@ with @c@ the
540-- value of every element. Subject to fusion.
1033-- value of every element. Subject to fusion.
541−replicate :: Int -> Char -> Text
1034+replicateChar :: Int -> Char -> Text
542−replicate n c = unstream (S.replicate n c)
1035+replicateChar n c = unstream (S.replicateCharI n (safe c))
543−{-# INLINE replicate #-}
1036+{-# INLINE replicateChar #-}
545-- | /O(n)/, where @n@ is the length of the result. The 'unfoldr'
1038-- | /O(n)/, where @n@ is the length of the result. The 'unfoldr'
546-- function is analogous to the List 'L.unfoldr'. 'unfoldr' builds a
1039-- function is analogous to the List 'L.unfoldr'. 'unfoldr' builds a
@@ -548,9 +1041,9 @@ replicate n c = unstream (S.replicate n c)
548-- returns 'Nothing' if it is done producing the 'Text', otherwise
1041-- returns 'Nothing' if it is done producing the 'Text', otherwise
549-- 'Just' @(a,b)@. In this case, @a@ is the next 'Char' in the
1042-- 'Just' @(a,b)@. In this case, @a@ is the next 'Char' in the
550-- string, and @b@ is the seed value for further production. Subject
1043-- string, and @b@ is the seed value for further production. Subject
551−-- to fusion.
1044+-- to fusion. Performs replacement on invalid scalar values.
552unfoldr :: (a -> Maybe (Char,a)) -> a -> Text
1045unfoldr :: (a -> Maybe (Char,a)) -> a -> Text
553−unfoldr f s = unstream (S.unfoldr f s)
1046+unfoldr f s = unstream (S.unfoldr (firstf safe . f) s)
554{-# INLINE unfoldr #-}
1047{-# INLINE unfoldr #-}
556-- | /O(n)/ Like 'unfoldr', 'unfoldrN' builds a 'Text' from a seed
1049-- | /O(n)/ Like 'unfoldr', 'unfoldrN' builds a 'Text' from a seed
@@ -558,9 +1051,9 @@ unfoldr f s = unstream (S.unfoldr f s)
558-- first argument to 'unfoldrN'. This function is more efficient than
1051-- first argument to 'unfoldrN'. This function is more efficient than
559-- 'unfoldr' when the maximum length of the result is known and
1052-- 'unfoldr' when the maximum length of the result is known and
560-- correct, otherwise its performance is similar to 'unfoldr'. Subject
1053-- correct, otherwise its performance is similar to 'unfoldr'. Subject
561−-- to fusion.
1054+-- to fusion. Performs replacement on invalid scalar values.
562unfoldrN :: Int -> (a -> Maybe (Char,a)) -> a -> Text
1055unfoldrN :: Int -> (a -> Maybe (Char,a)) -> a -> Text
563−unfoldrN n f s = unstream (S.unfoldrN n f s)
1056+unfoldrN n f s = unstream (S.unfoldrN n (firstf safe . f) s)
564{-# INLINE unfoldrN #-}
1057{-# INLINE unfoldrN #-}
566-- -----------------------------------------------------------------------------
1059-- -----------------------------------------------------------------------------
@@ -573,14 +1066,16 @@ take :: Int -> Text -> Text
573take n t@(Text arr off len)
1066take n t@(Text arr off len)
574 | n <= 0 = empty
1067 | n <= 0 = empty
575 | n >= len = t
1068 | n >= len = t
576− | otherwise = Text arr off (loop 0 0)
1069+ | otherwise = text arr off (iterN n t)
579− | i >= len || cnt >= n = i
580− | otherwise = loop (i+d) (cnt+1)
582{-# INLINE [1] take #-}
1070{-# INLINE [1] take #-}
1072+iterN :: Int -> Text -> Int
1073+iterN n t@(Text _arr _off len) = loop 0 0
1075+ | i >= len || cnt >= n = i
1076+ | otherwise = loop (i+d) (cnt+1)
1077+ where d = iter_ t i
584{-# RULES
1079{-# RULES
585"TEXT take -> fused" [~1] forall n t.
1080"TEXT take -> fused" [~1] forall n t.
586 take n t = unstream (S.take n (stream t))
1081 take n t = unstream (S.take n (stream t))
@@ -588,18 +1083,36 @@ take n t@(Text arr off len)
588 unstream (S.take n (stream t)) = take n t
1083 unstream (S.take n (stream t)) = take n t
1086+-- | /O(n)/ 'takeEnd' @n@ @t@ returns the suffix remaining after
1087+-- taking @n@ characters from the end of @t@.
1091+-- > takeEnd 3 "foobar" == "bar"
1092+takeEnd :: Int -> Text -> Text
1093+takeEnd n t@(Text arr off len)
1096+ | otherwise = text arr (off+i) (len-i)
1097+ where i = iterNEnd n t
1099+iterNEnd :: Int -> Text -> Int
1100+iterNEnd n t@(Text _arr _off len) = loop (len-1) n
1104+ | otherwise = loop (i+d) (m-1)
1105+ where d = reverseIter_ t i
591-- | /O(n)/ 'drop' @n@, applied to a 'Text', returns the suffix of the
1107-- | /O(n)/ 'drop' @n@, applied to a 'Text', returns the suffix of the
592−-- 'Text' of length @n@, or the empty 'Text' if @n@ is greater than the
1108+-- 'Text' after the first @n@ characters, or the empty 'Text' if @n@
593−-- length of the 'Text'. Subject to fusion.
1109+-- is greater than the length of the 'Text'. Subject to fusion.
594drop :: Int -> Text -> Text
1110drop :: Int -> Text -> Text
595drop n t@(Text arr off len)
1111drop n t@(Text arr off len)
596 | n <= 0 = t
1112 | n <= 0 = t
597 | n >= len = empty
1113 | n >= len = empty
598− | otherwise = loop 0 0
1114+ | otherwise = text arr (off+i) (len-i)
600− | i >= len || cnt >= n = Text arr (off+i) (len-i)
601− | otherwise = loop (i+d) (cnt+1)
602− where d = iter_ t i
1115+ where i = iterN n t
603{-# INLINE [1] drop #-}
1116{-# INLINE [1] drop #-}
605{-# RULES
1118{-# RULES
@@ -609,15 +1122,27 @@ drop n t@(Text arr off len)
609 unstream (S.drop n (stream t)) = drop n t
1122 unstream (S.drop n (stream t)) = drop n t
1125+-- | /O(n)/ 'dropEnd' @n@ @t@ returns the prefix remaining after
1126+-- dropping @n@ characters from the end of @t@.
1130+-- > dropEnd 3 "foobar" == "foo"
1131+dropEnd :: Int -> Text -> Text
1132+dropEnd n t@(Text arr off len)
1135+ | otherwise = text arr off (iterNEnd n t)
612−-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text', returns
1137+-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text',
613−-- the longest prefix (possibly empty) of elements that satisfy @p@.
1138+-- returns the longest prefix (possibly empty) of elements that
614−-- This function is subject to array fusion.
1139+-- satisfy @p@. Subject to fusion.
615takeWhile :: (Char -> Bool) -> Text -> Text
1140takeWhile :: (Char -> Bool) -> Text -> Text
616takeWhile p t@(Text arr off len) = loop 0
1141takeWhile p t@(Text arr off len) = loop 0
617 where loop !i | i >= len = t
1142 where loop !i | i >= len = t
618 | p c = loop (i+d)
1143 | p c = loop (i+d)
619− | otherwise = textP arr off i
1144+ | otherwise = text arr off i
620− where (c,d) = iter t i
1145+ where Iter c d = iter t i
621{-# INLINE [1] takeWhile #-}
1146{-# INLINE [1] takeWhile #-}
623{-# RULES
1148{-# RULES
@@ -627,14 +1152,35 @@ takeWhile p t@(Text arr off len) = loop 0
627 unstream (S.takeWhile p (stream t)) = takeWhile p t
1152 unstream (S.takeWhile p (stream t)) = takeWhile p t
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.
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 #-}
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
630−-- | /O(n)/ 'dropWhile' @p@ @xs@ returns the suffix remaining after
1176+-- | /O(n)/ 'dropWhile' @p@ @t@ returns the suffix remaining after
631−-- 'takeWhile' @p@ @xs@. This function is subject to array fusion.
1177+-- 'takeWhile' @p@ @t@. Subject to fusion.
632dropWhile :: (Char -> Bool) -> Text -> Text
1178dropWhile :: (Char -> Bool) -> Text -> Text
633dropWhile p t@(Text arr off len) = loop 0 0
1179dropWhile p t@(Text arr off len) = loop 0 0
634 where loop !i !l | l >= len = empty
1180 where loop !i !l | l >= len = empty
635 | p c = loop (i+d) (l+d)
1181 | p c = loop (i+d) (l+d)
636 | otherwise = Text arr (off+i) (len-l)
1182 | otherwise = Text arr (off+i) (len-l)
637− where (c,d) = iter t i
1183+ where Iter c d = iter t i
638{-# INLINE [1] dropWhile #-}
1184{-# INLINE [1] dropWhile #-}
640{-# RULES
1186{-# RULES
@@ -644,6 +1190,57 @@ dropWhile p t@(Text arr off len) = loop 0 0
644 unstream (S.dropWhile p (stream t)) = dropWhile p t
1190 unstream (S.dropWhile p (stream t)) = dropWhile p t
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.
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 #-}
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
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 #-}
1222+-- | /O(n)/ Remove leading white space from a string. Equivalent to:
1224+-- > dropWhile isSpace
1225+stripStart :: Text -> Text
1226+stripStart = dropWhile isSpace
1227+{-# INLINE [1] stripStart #-}
1229+-- | /O(n)/ Remove trailing white space from a string. Equivalent to:
1231+-- > dropWhileEnd isSpace
1232+stripEnd :: Text -> Text
1233+stripEnd = dropWhileEnd isSpace
1234+{-# INLINE [1] stripEnd #-}
1236+-- | /O(n)/ Remove leading and trailing white space from a string.
1239+-- > dropAround isSpace
1240+strip :: Text -> Text
1241+strip = dropAround isSpace
1242+{-# INLINE [1] strip #-}
647-- | /O(n)/ 'splitAt' @n t@ returns a pair whose first element is a
1244-- | /O(n)/ 'splitAt' @n t@ returns a pair whose first element is a
648-- prefix of @t@ of length @n@, and whose second is the remainder of
1245-- prefix of @t@ of length @n@, and whose second is the remainder of
649-- the string. It is equivalent to @('take' n t, 'drop' n t)@.
1246-- the string. It is equivalent to @('take' n t, 'drop' n t)@.
@@ -651,28 +1248,20 @@ splitAt :: Int -> Text -> (Text, Text)
651splitAt n t@(Text arr off len)
1248splitAt n t@(Text arr off len)
652 | n <= 0 = (empty, t)
1249 | n <= 0 = (empty, t)
653 | n >= len = (t, empty)
1250 | n >= len = (t, empty)
654− | otherwise = (Text arr off k, Text arr (off+k) (len-k))
1251+ | otherwise = let k = iterN n t
655− where k = loop 0 0
1252+ in (text arr off k, text arr (off+k) (len-k))
657− | i >= len || cnt >= n = i
658− | otherwise = loop (i+d) (cnt+1)
660−{-# INLINE splitAt #-}
662−-- | /O(n)/ 'span', applied to a predicate @p@ and text @t@, returns a
1254+-- | /O(n)/ 'span', applied to a predicate @p@ and text @t@, returns
663−-- pair whose first element is the longest prefix (possibly empty) of
1255+-- a pair whose first element is the longest prefix (possibly empty)
664−-- @t@ of elements that satisfy @p@, and whose second is the remainder
1256+-- of @t@ of elements that satisfy @p@, and whose second is the
665−-- of the list.
1257+-- remainder of the list.
666span :: (Char -> Bool) -> Text -> (Text, Text)
1258span :: (Char -> Bool) -> Text -> (Text, Text)
667−span p t@(Text arr off len) = (textP arr off k, textP arr (off+k) (len-k))
1259+span p t = case span_ p t of
668− where k = loop 0
1260+ (# hd,tl #) -> (hd,tl)
669− loop !i | i >= len || not (p c) = i
670− | otherwise = loop (i+d)
671− where (c,d) = iter t i
672{-# INLINE span #-}
1261{-# INLINE span #-}
674−-- | /O(n)/ 'break' is like 'span', but the prefix returned is over
1263+-- | /O(n)/ 'break' is like 'span', but the prefix returned is
675−-- elements that fail the predicate @p@.
1264+-- over elements that fail the predicate @p@.
676break :: (Char -> Bool) -> Text -> (Text, Text)
1265break :: (Char -> Bool) -> Text -> (Text, Text)
677break p = span (not . p)
1266break p = span (not . p)
678{-# INLINE break #-}
1267{-# INLINE break #-}
@@ -684,7 +1273,7 @@ groupBy p = loop
684 loop t@(Text arr off len)
1273 loop t@(Text arr off len)
685 | null t = []
1274 | null t = []
686 | otherwise = text arr off n : loop (text arr (off+n) (len-n))
1275 | otherwise = text arr off n : loop (text arr (off+n) (len-n))
687− where (c,d) = iter t 0
1276+ where Iter c d = iter t 0
688 n = d + findAIndexOrEnd (not . p c) (Text arr (off+d) (len-d))
1277 n = d + findAIndexOrEnd (not . p c) (Text arr (off+d) (len-d))
690-- | Returns the /array/ index (in units of 'Word16') at which a
1279-- | Returns the /array/ index (in units of 'Word16') at which a
@@ -694,8 +1283,8 @@ findAIndexOrEnd :: (Char -> Bool) -> Text -> Int
694findAIndexOrEnd q t@(Text _arr _off len) = go 0
1283findAIndexOrEnd q t@(Text _arr _off len) = go 0
695 where go !i | i >= len || q c = i
1284 where go !i | i >= len || q c = i
696 | otherwise = go (i+d)
1285 | otherwise = go (i+d)
697− where (c,d) = iter t i
1286+ where Iter c d = iter t i
699-- | /O(n)/ Group characters in a string by equality.
1288-- | /O(n)/ Group characters in a string by equality.
700group :: Text -> [Text]
1289group :: Text -> [Text]
701group = groupBy (==)
1290group = groupBy (==)
@@ -713,59 +1302,91 @@ tails :: Text -> [Text]
713tails t | null t = [empty]
1302tails t | null t = [empty]
714 | otherwise = t : tails (unsafeTail t)
1303 | otherwise = t : tails (unsafeTail t)
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.
716−-- | /O(n)/ Break a 'Text' into pieces separated by the 'Char'
1311+-- | /O(m+n)/ Break a 'Text' into pieces separated by the first 'Text'
717−-- argument, consuming the delimiter. I.e.
1312+-- argument (which cannot be empty), consuming the delimiter. An empty
1313+-- delimiter is invalid, and will cause an error to be raised.
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" == ["",""]
719−-- > split '\n' "a\nb\nd\ne" == ["a","b","d","e"]
720−-- > split 'a' "aXaXaXa" == ["","X","X","X",""]
721−-- > split 'x' "x" == ["",""]
725−-- > intercalate (singleton c) . split c == id
1323+-- > intercalate s . splitOn s == id
726−-- > split == splitWith . (==)
1324+-- > splitOn (singleton c) == split (==c)
728−-- As for all splitting functions in this library, this function does
1326+-- (Note: the string @s@ to split on above cannot be empty.)
729−-- not copy the substrings, it just constructs new 'Text's that are
1327+--
730−-- slices of the original.
1328+-- In (unlikely) bad cases, this function's time complexity degrades
731−split :: Char -> Text -> [Text]
1329+-- towards /O(n*m)/.
732−split c = splitWith (==c)
1330+splitOn :: Text
1331+ -- ^ String to split on. If this string is empty, an error
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)
1341+ go !s (x:xs) = text arr (s+off) (x-s) : go (x+l) xs
1342+ go s _ = [text arr (s+off) (len-s)]
733−{-# INLINE split #-}
1343+{-# INLINE [1] splitOn #-}
1346+"TEXT splitOn/singleton -> split/==" [~1] forall c t.
1347+ splitOn (singleton c) t = split (==c) t
735-- | /O(n)/ Splits a 'Text' into components delimited by separators,
1350-- | /O(n)/ Splits a 'Text' into components delimited by separators,
736-- where the predicate returns True for a separator element. The
1351-- where the predicate returns True for a separator element. The
737-- resulting components do not contain the separators. Two adjacent
1352-- resulting components do not contain the separators. Two adjacent
738-- separators result in an empty component in the output. eg.
1353-- separators result in an empty component in the output. eg.
740−-- > splitWith (=='a') "aabbaca" == ["","","bb","c",""]
1355+-- > split (=='a') "aabbaca" == ["","","bb","c",""]
741−-- > splitWith (=='a') [] == []
1356+-- > split (=='a') "" == [""]
742−splitWith :: (Char -> Bool) -> Text -> [Text]
1357+split :: (Char -> Bool) -> Text -> [Text]
743−splitWith _ (Text _off _arr 0) = []
1358+split _ t@(Text _off _arr 0) = [t]
744−splitWith p t = loop t
1359+split p t = loop t
745 where loop s | null s' = [l]
1360 where loop s | null s' = [l]
746 | otherwise = l : loop (unsafeTail s')
1361 | otherwise = l : loop (unsafeTail s')
747− where (l, s') = break p s
1362+ where (# l, s' #) = span_ (not . p) s
748−{-# INLINE splitWith #-}
1363+{-# INLINE split #-}
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:
1369+-- > chunksOf 3 "foobarbaz" == ["foo","bar","baz"]
1370+-- > chunksOf 4 "haskell.org" == ["hask","ell.","org"]
1371+chunksOf :: Int -> Text -> [Text]
1374+ go t = case splitAt k t of
1375+ (a,b) | null a -> []
1376+ | otherwise -> a : go b
1377+{-# INLINE chunksOf #-}
750-- ----------------------------------------------------------------------------
1379-- ----------------------------------------------------------------------------
751-- * Searching
1380-- * Searching
753−-------------------------------------------------------------------------------
754−-- ** Searching by equality
756−-- | /O(n)/ 'elem' is the 'Text' membership predicate.
757−elem :: Char -> Text -> Bool
758−elem c t = S.elem c (stream t)
761-------------------------------------------------------------------------------
1382-------------------------------------------------------------------------------
762-- ** Searching with a predicate
1383-- ** Searching with a predicate
764−-- | /O(n)/ The 'find' function takes a predicate and a 'Text',
1385+-- | /O(n)/ The 'find' function takes a predicate and a 'Text', and
765−-- and returns the first element in matching the predicate, or 'Nothing'
1386+-- returns the first element matching the predicate, or 'Nothing' if
766−-- if there is no such element.
1387+-- there is no such element.
767find :: (Char -> Bool) -> Text -> Maybe Char
1388find :: (Char -> Bool) -> Text -> Maybe Char
768−find p t = S.find p (stream t)
1389+find p t = S.findBy p (stream t)
769{-# INLINE find #-}
1390{-# INLINE find #-}
771-- | /O(n)/ The 'partition' function takes a predicate and a 'Text',
1392-- | /O(n)/ The 'partition' function takes a predicate and a 'Text',
@@ -777,49 +1398,103 @@ partition :: (Char -> Bool) -> Text -> (Text, Text)
777partition p t = (filter p t, filter (not . p) t)
1398partition p t = (filter p t, filter (not . p) t)
778{-# INLINE partition #-}
1399{-# INLINE partition #-}
780−-- | /O(n)/ Break a string on a substring, returning a pair of the
1401+-- | /O(n)/ 'filter', applied to a predicate and a 'Text',
781−-- part of the string prior to the match, and the rest of the string.
1402+-- returns a 'Text' containing those characters that satisfy the
1404+filter :: (Char -> Bool) -> Text -> Text
1405+filter p t = unstream (S.filter p (stream t))
1406+{-# INLINE filter #-}
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.
783−-- The following relationship holds:
1413+-- Examples:
785−-- > break (==c) l == breakSubstring (singleton c) l
1415+-- > breakOn "::" "a::b::c" ==> ("a", "::b::c")
1416+-- > breakOn "/" "foobar" ==> ("foobar", "")
787−-- For example, to tokenise a string, dropping delimiters:
1418+-- Laws:
789−-- > tokenise x y = h : if null t then [] else tokenise x (drop (length x) t)
1420+-- > append prefix match == haystack
790−-- > where (h,t) = breakSubstring x y
1421+-- > where (prefix, match) = breakOn needle haystack
792−-- To skip to the first occurence of a string:
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.
794−-- > snd (breakSubstring x y)
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
1434+ (x:_) -> (text arr off x, text arr (off+x) (len-x))
1435+{-# INLINE breakOn #-}
1437+-- | /O(n+m)/ Similar to 'breakOn', but searches from the end of the
796−-- To take the parts of a string before a delimiter:
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.
798−-- > fst (breakSubstring x y)
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 #-}
1450+-- | /O(n+m)/ Find all non-overlapping instances of @needle@ in
1451+-- @haystack@. Each element of the returned list consists of a pair:
800−breakSubstring :: Text -- ^ String to search for
1453+-- * The entire string prior to the /k/th match (i.e. the prefix)
801− -> Text -- ^ String to search in
1454+--
802− -> (Text,Text) -- ^ Head and tail of string broken at substring
1455+-- * The /k/th match, followed by the remainder of the string
804−breakSubstring pat src = search 0 src
1457+-- Examples:
1459+-- > breakOnAll "::" ""
1461+-- > breakOnAll "/" "a/b/c/"
1462+-- > ==> [("a", "/b/c/"), ("a/b", "/c/"), ("a/b/c", "/")]
1464+-- In (unlikely) bad cases, this function's time complexity degrades
1465+-- towards /O(n*m)/.
1467+-- The @needle@ parameter may not be empty.
1468+breakOnAll :: Text -- ^ @needle@ to search for
1469+ -> Text -- ^ @haystack@ in which to search
1471+breakOnAll pat src@(Text arr off slen)
1472+ | null pat = emptyError "breakOnAll"
1473+ | otherwise = L.map step (indices pat src)
806− search !n !s
1475+ step x = (chunk 0 x, chunk x (slen-x))
807− | null s = (src,empty) -- not found
1476+ chunk !n !l = text arr (n+off) l
808− | pat `isPrefixOf` s = (take n src,s)
1477+{-# INLINE breakOnAll #-}
809− | otherwise = search (n+1) (unsafeTail s)
810−{-# INLINE breakSubstring #-}
812−-- | /O(n)/ 'filter', applied to a predicate and a 'Text',
813−-- returns a 'Text' containing those characters that satisfy the
815−filter :: (Char -> Bool) -> Text -> Text
816−filter p t = unstream (S.filter p (stream t))
817−{-# INLINE filter #-}
820-------------------------------------------------------------------------------
1479-------------------------------------------------------------------------------
821-- ** Indexing 'Text's
1480-- ** Indexing 'Text's
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.
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.
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 \"::\"@.
823-- | /O(n)/ 'Text' index (subscript) operator, starting from 0.
1498-- | /O(n)/ 'Text' index (subscript) operator, starting from 0.
824index :: Text -> Int -> Char
1499index :: Text -> Int -> Char
825index t n = S.index (stream t) n
1500index t n = S.index (stream t) n
@@ -827,48 +1502,53 @@ index t n = S.index (stream t) n
828-- | /O(n)/ The 'findIndex' function takes a predicate and a 'Text'
1503-- | /O(n)/ The 'findIndex' function takes a predicate and a 'Text'
829-- and returns the index of the first element in the 'Text' satisfying
1504-- and returns the index of the first element in the 'Text' satisfying
830−-- the predicate. This function is subject to fusion.
1505+-- the predicate. Subject to fusion.
831findIndex :: (Char -> Bool) -> Text -> Maybe Int
1506findIndex :: (Char -> Bool) -> Text -> Maybe Int
832findIndex p t = S.findIndex p (stream t)
1507findIndex p t = S.findIndex p (stream t)
833{-# INLINE findIndex #-}
1508{-# INLINE findIndex #-}
835−-- | The 'findIndices' function extends 'findIndex', by returning the
1510+-- | /O(n+m)/ The 'count' function returns the number of times the
836−-- indices of all elements satisfying the predicate, in ascending
1511+-- query string appears in the given 'Text'. An empty query string is
837−-- order. This function is subject to fusion.
1512+-- invalid, and will cause an error to be raised.
838−findIndices :: (Char -> Bool) -> Text -> [Int]
1513+--
839−findIndices p t = S.findIndices p (stream t)
1514+-- In (unlikely) bad cases, this function's time complexity degrades
1515+-- towards /O(n*m)/.
1516+count :: Text -> Text -> Int
1518+ | null pat = emptyError "count"
1519+ | isSingleton pat = countChar (unsafeHead pat) src
1520+ | otherwise = L.length (indices pat src)
840−{-# INLINE findIndices #-}
1521+{-# INLINE [1] count #-}
842−-- | /O(n)/ The 'elemIndex' function returns the index of the first
1523+{-# RULES
843−-- element in the given 'Text' which is equal to the query element, or
1524+"TEXT count/singleton -> countChar" [~1] forall c t.
844−-- 'Nothing' if there is no such element. This function is subject to
1525+ count (singleton c) t = countChar c t
846−elemIndex :: Char -> Text -> Maybe Int
1527+
847−elemIndex c t = S.elemIndex c (stream t)
848−{-# INLINE elemIndex #-}
850−-- | /O(n)/ The 'elemIndices' function returns the index of every
851−-- element in the given 'Text' which is equal to the query
852−-- element. This function is subject to fusion.
853−elemIndices :: Char -> Text -> [Int]
854−elemIndices c t = S.elemIndices c (stream t)
855−{-# INLINE elemIndices #-}
857−-- | /O(n)/ The 'count' function returns the number of times the query
1528+-- | /O(n)/ The 'countChar' function returns the number of times the
858−-- element appears in the given 'Text'. This function is subject to
1529+-- query element appears in the given 'Text'. Subject to fusion.
860−count :: Char -> Text -> Int
1530+countChar :: Char -> Text -> Int
861−count c t = S.count c (stream t)
1531+countChar c t = S.countChar c (stream t)
862−{-# INLINE count #-}
1532+{-# INLINE countChar #-}
864-------------------------------------------------------------------------------
1534-------------------------------------------------------------------------------
865-- * Zipping
1535-- * Zipping
1537+-- | /O(n)/ 'zip' takes two 'Text's and returns a list of
1538+-- corresponding pairs of bytes. If one input 'Text' is short,
1539+-- excess elements of the longer 'Text' are discarded. This is
1540+-- equivalent to a pair of 'unpack' operations.
1541+zip :: Text -> Text -> [(Char,Char)]
1542+zip a b = S.unstreamList $ S.zipWith (,) (stream a) (stream b)
867-- | /O(n)/ 'zipWith' generalises 'zip' by zipping with the function
1545-- | /O(n)/ 'zipWith' generalises 'zip' by zipping with the function
868-- given as the first argument, instead of a tupling function.
1546-- given as the first argument, instead of a tupling function.
1547+-- Performs replacement on invalid scalar values.
869zipWith :: (Char -> Char -> Char) -> Text -> Text -> Text
1548zipWith :: (Char -> Char -> Char) -> Text -> Text -> Text
870−zipWith f t1 t2 = unstream (S.zipWith f (stream t1) (stream t2))
1549+zipWith f t1 t2 = unstream (S.zipWith g (stream t1) (stream t2))
1550+ where g a b = safe (f a b)
871−{-# INLINE [0] zipWith #-}
1551+{-# INLINE zipWith #-}
873-- | /O(n)/ Breaks a 'Text' up into a list of words, delimited by 'Char's
1553-- | /O(n)/ Breaks a 'Text' up into a list of words, delimited by 'Char's
874-- representing white space.
1554-- representing white space.
@@ -884,7 +1564,7 @@ words t@(Text arr off len) = loop 0 0
884 then loop (start+1) (start+1)
1564 then loop (start+1) (start+1)
885 else Text arr (start+off) (n-start) : loop (n+d) (n+d)
1565 else Text arr (start+off) (n-start) : loop (n+d) (n+d)
886 | otherwise = loop start (n+d)
1566 | otherwise = loop start (n+d)
887− where (c,d) = iter t n
1567+ where Iter c d = iter t n
888{-# INLINE words #-}
1568{-# INLINE words #-}
890-- | /O(n)/ Breaks a 'Text' up into a list of 'Text's at
1570-- | /O(n)/ Breaks a 'Text' up into a list of 'Text's at
@@ -894,9 +1574,10 @@ lines ps | null ps = []
894 | otherwise = h : if null t
1574 | otherwise = h : if null t
896 else lines (unsafeTail t)
1576 else lines (unsafeTail t)
897− where (h,t) = span (/= '\n') ps
1577+ where (# h,t #) = span_ (/= '\n') ps
898{-# INLINE lines #-}
1578{-# INLINE lines #-}
900-- | /O(n)/ Portably breaks a 'Text' up into a list of 'Text's at line
1581-- | /O(n)/ Portably breaks a 'Text' up into a list of 'Text's at line
901-- boundaries.
1582-- boundaries.
@@ -904,7 +1585,6 @@ lines ps | null ps = []
904-- return immediately followed by a line feed, or a carriage return.
1585-- return immediately followed by a line feed, or a carriage return.
905-- This accounts for both Unix and Windows line ending conventions,
1586-- This accounts for both Unix and Windows line ending conventions,
906-- and for the old convention used on Mac OS 9 and earlier.
1587-- and for the old convention used on Mac OS 9 and earlier.
908lines' :: Text -> [Text]
1588lines' :: Text -> [Text]
909lines' ps | null ps = []
1589lines' ps | null ps = []
910 | otherwise = h : case uncons t of
1590 | otherwise = h : case uncons t of
@@ -931,8 +1611,7 @@ unwords = intercalate (singleton ' ')
931{-# INLINE unwords #-}
1611{-# INLINE unwords #-}
933-- | /O(n)/ The 'isPrefixOf' function takes two 'Text's and returns
1613-- | /O(n)/ The 'isPrefixOf' function takes two 'Text's and returns
934−-- 'True' iff the first is a prefix of the second. This function is
1614+-- 'True' iff the first is a prefix of the second. Subject to fusion.
935−-- subject to fusion.
936isPrefixOf :: Text -> Text -> Bool
1615isPrefixOf :: Text -> Text -> Bool
937isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) =
1616isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) =
938 alen <= blen && S.isPrefixOf (stream a) (stream b)
1617 alen <= blen && S.isPrefixOf (stream a) (stream b)
@@ -941,8 +1620,6 @@ isPrefixOf a@(Text _ _ alen) b@(Text _ _ blen) =
941{-# RULES
1620{-# RULES
942"TEXT isPrefixOf -> fused" [~1] forall s t.
1621"TEXT isPrefixOf -> fused" [~1] forall s t.
943 isPrefixOf s t = S.isPrefixOf (stream s) (stream t)
1622 isPrefixOf s t = S.isPrefixOf (stream s) (stream t)
944−"TEXT isPrefixOf -> unfused" [1] forall s t.
945− S.isPrefixOf (stream s) (stream t) = isPrefixOf s t
948-- | /O(n)/ The 'isSuffixOf' function takes two 'Text's and returns
1625-- | /O(n)/ The 'isSuffixOf' function takes two 'Text's and returns
@@ -955,13 +1632,124 @@ isSuffixOf a@(Text _aarr _aoff alen) b@(Text barr boff blen) =
955 | otherwise = Text barr (boff+d) alen
1632 | otherwise = Text barr (boff+d) alen
956{-# INLINE isSuffixOf #-}
1633{-# INLINE isSuffixOf #-}
958−-- | /O(n)/ The 'isInfixOf' function takes two 'Text's and returns
1635+-- | /O(n+m)/ The 'isInfixOf' function takes two 'Text's and returns
959-- 'True' iff the first is contained, wholly and intact, anywhere
1636-- 'True' iff the first is contained, wholly and intact, anywhere
960-- within the second.
1637-- within the second.
1639+-- In (unlikely) bad cases, this function's time complexity degrades
1640+-- towards /O(n*m)/.
961isInfixOf :: Text -> Text -> Bool
1641isInfixOf :: Text -> Text -> Bool
962−isInfixOf needle haystack = L.any (isPrefixOf needle) (tails haystack)
1642+isInfixOf needle haystack
963−{-# INLINE isInfixOf #-}
1643+ | null needle = True
964−-- TODO: a better implementation
1644+ | isSingleton needle = S.elem (unsafeHead needle) . S.stream $ haystack
1645+ | otherwise = not . L.null . indices needle $ haystack
1646+{-# INLINE [1] isInfixOf #-}
1649+"TEXT isInfixOf/singleton -> S.elem/S.stream" [~1] forall n h.
1650+ isInfixOf (singleton n) h = S.elem n (S.stream h)
1653+-------------------------------------------------------------------------------
1656+-- | /O(n)/ Return the suffix of the second string if its prefix
1657+-- matches the entire first string.
1661+-- > stripPrefix "foo" "foobar" == Just "bar"
1662+-- > stripPrefix "" "baz" == Just "baz"
1663+-- > stripPrefix "foo" "quux" == Nothing
1665+-- This is particularly useful with the @ViewPatterns@ extension to
1668+-- > {-# LANGUAGE ViewPatterns #-}
1669+-- > import Data.Text as T
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
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
1683+-- If the strings do not have a common prefix or either one is empty,
1684+-- this function returns 'Nothing'.
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
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
1702+-- | /O(n)/ Return the prefix of the second string if its suffix
1703+-- matches the entire first string.
1707+-- > stripSuffix "bar" "foobar" == Just "foo"
1708+-- > stripSuffix "" "baz" == Just "baz"
1709+-- > stripSuffix "foo" "quux" == Nothing
1711+-- This is particularly useful with the @ViewPatterns@ extension to
1714+-- > {-# LANGUAGE ViewPatterns #-}
1715+-- > import Data.Text as T
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
1725+-- | Add a list of non-negative numbers. Errors out on overflow.
1726+sumP :: String -> [Int] -> Int
1729+ | ax >= 0 = go ax xs
1730+ | otherwise = overflowError fun
966emptyError :: String -> a
1734emptyError :: String -> a
967−emptyError fun = P.error ("Data.Text." ++ fun ++ ": empty input")
1735+emptyError fun = P.error $ "Data.Text." ++ fun ++ ": empty input"
1737+overflowError :: String -> a
1738+overflowError fun = P.error $ "Data.Text." ++ fun ++ ": size overflow"
1740+-- | /O(n)/ Make a distinct copy of the given string, sharing no
1741+-- storage with the original string.
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
1751+ go :: ST s (A.MArray s)
1754+ A.copyI marr 0 arr off len