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9667f797 GG |
1 | {-# LANGUAGE RankNTypes, TypeFamilies, BangPatterns, Trustworthy #-} |
2 | ||
91727d11 | 3 | |
7faef8bc | 4 | module Pipes.Text ( |
82fe661b | 5 | -- * Effectful Text |
e4b6dc67 | 6 | -- $intro |
7 | ||
82fe661b | 8 | -- * Lenses |
9 | -- $lenses | |
10 | ||
11 | -- ** @view@ \/ @(^.)@ | |
12 | -- $view | |
13 | ||
14 | -- ** @over@ \/ @(%~)@ | |
15 | -- $over | |
16 | ||
17 | -- ** @zoom@ | |
18 | -- $zoom | |
19 | ||
20 | -- * Special types: @Producer Text m (Producer Text m r)@ and @FreeT (Producer Text m) m r@ | |
21 | -- $special | |
22 | ||
91727d11 | 23 | -- * Producers |
1a83ae4e | 24 | fromLazy |
91727d11 | 25 | |
26 | -- * Pipes | |
1677dc12 | 27 | , map |
28 | , concatMap | |
29 | , take | |
30 | , drop | |
31 | , takeWhile | |
32 | , dropWhile | |
33 | , filter | |
34 | , scan | |
1677dc12 | 35 | , pack |
36 | , unpack | |
37 | , toCaseFold | |
38 | , toLower | |
39 | , toUpper | |
40 | , stripStart | |
91727d11 | 41 | |
42 | -- * Folds | |
1677dc12 | 43 | , toLazy |
44 | , toLazyM | |
45 | , foldChars | |
46 | , head | |
47 | , last | |
48 | , null | |
49 | , length | |
50 | , any | |
51 | , all | |
52 | , maximum | |
53 | , minimum | |
54 | , find | |
55 | , index | |
56 | , count | |
57 | ||
58 | -- * Primitive Character Parsers | |
1677dc12 | 59 | , nextChar |
60 | , drawChar | |
61 | , unDrawChar | |
62 | , peekChar | |
9e9bb0ce | 63 | , isEndOfChars |
1677dc12 | 64 | |
65 | -- * Parsing Lenses | |
9e9bb0ce | 66 | , splitAt |
1677dc12 | 67 | , span |
68 | , break | |
69 | , groupBy | |
70 | , group | |
9e9bb0ce | 71 | , word |
72 | , line | |
1677dc12 | 73 | |
74 | -- * FreeT Splitters | |
75 | , chunksOf | |
76 | , splitsWith | |
0f8c6f1b | 77 | , splits |
1a83ae4e | 78 | , groupsBy |
79 | , groups | |
1677dc12 | 80 | , lines |
81 | , words | |
82 | ||
91727d11 | 83 | -- * Transformations |
1677dc12 | 84 | , intersperse |
9e9bb0ce | 85 | , packChars |
31f41a5d | 86 | |
91727d11 | 87 | -- * Joiners |
1677dc12 | 88 | , intercalate |
89 | , unlines | |
90 | , unwords | |
9e9bb0ce | 91 | |
1a83ae4e | 92 | -- * Re-exports |
91727d11 | 93 | -- $reexports |
1677dc12 | 94 | , module Data.ByteString |
95 | , module Data.Text | |
96 | , module Data.Profunctor | |
1677dc12 | 97 | , module Pipes.Parse |
7ed76745 | 98 | , module Pipes.Group |
91727d11 | 99 | ) where |
100 | ||
0f8c6f1b | 101 | import Control.Applicative ((<*)) |
70125641 | 102 | import Control.Monad (liftM, join) |
9e9bb0ce | 103 | import Control.Monad.Trans.State.Strict (StateT(..), modify) |
91727d11 | 104 | import qualified Data.Text as T |
91727d11 | 105 | import Data.Text (Text) |
106 | import qualified Data.Text.Lazy as TL | |
31f41a5d | 107 | import Data.ByteString (ByteString) |
1677dc12 | 108 | import Data.Functor.Constant (Constant(Constant, getConstant)) |
91727d11 | 109 | import Data.Functor.Identity (Identity) |
1677dc12 | 110 | import Data.Profunctor (Profunctor) |
111 | import qualified Data.Profunctor | |
91727d11 | 112 | import Pipes |
7fc48f7c | 113 | import Pipes.Group (concats, intercalates, FreeT(..), FreeF(..)) |
7ed76745 | 114 | import qualified Pipes.Group as PG |
91727d11 | 115 | import qualified Pipes.Parse as PP |
7ed76745 | 116 | import Pipes.Parse (Parser) |
79917d53 | 117 | import Pipes.Text.Encoding (Lens'_, Iso'_) |
91727d11 | 118 | import qualified Pipes.Prelude as P |
91727d11 | 119 | import Data.Char (isSpace) |
1a83ae4e | 120 | import Data.Word (Word8) |
79917d53 | 121 | import Foreign.Storable (sizeOf) |
122 | import Data.Bits (shiftL) | |
91727d11 | 123 | import Prelude hiding ( |
124 | all, | |
125 | any, | |
126 | break, | |
127 | concat, | |
128 | concatMap, | |
129 | drop, | |
130 | dropWhile, | |
131 | elem, | |
132 | filter, | |
133 | head, | |
134 | last, | |
135 | lines, | |
136 | length, | |
137 | map, | |
138 | maximum, | |
139 | minimum, | |
140 | notElem, | |
141 | null, | |
142 | readFile, | |
143 | span, | |
144 | splitAt, | |
145 | take, | |
146 | takeWhile, | |
147 | unlines, | |
148 | unwords, | |
149 | words, | |
150 | writeFile ) | |
151 | ||
e4b6dc67 | 152 | {- $intro |
e1ed9621 | 153 | This package provides @pipes@ utilities for /text streams/ or /character streams/, |
154 | realized as streams of 'Text' chunks. The individual chunks are uniformly /strict/, | |
155 | and thus you will generally want @Data.Text@ in scope. But the type | |
156 | @Producer Text m r@ ,as we are using it, is a sort of /pipes/ equivalent of the lazy @Text@ type. | |
e4b6dc67 | 157 | |
158 | This particular module provides many functions equivalent in one way or another to | |
159 | the pure functions in | |
160 | <https://hackage.haskell.org/package/text-1.1.0.0/docs/Data-Text-Lazy.html Data.Text.Lazy>. | |
161 | They transform, divide, group and fold text streams. Though @Producer Text m r@ | |
162 | is the type of \'effectful Text\', the functions in this module are \'pure\' | |
163 | in the sense that they are uniformly monad-independent. | |
164 | Simple /IO/ operations are defined in @Pipes.Text.IO@ -- as lazy IO @Text@ | |
165 | operations are in @Data.Text.Lazy.IO@. Inter-operation with @ByteString@ | |
166 | is provided in @Pipes.Text.Encoding@, which parallels @Data.Text.Lazy.Encoding@. | |
167 | ||
168 | The Text type exported by @Data.Text.Lazy@ is basically that of a lazy list of | |
169 | strict Text: the implementation is arranged so that the individual strict 'Text' | |
170 | chunks are kept to a reasonable size; the user is not aware of the divisions | |
171 | between the connected 'Text' chunks. | |
172 | So also here: the functions in this module are designed to operate on streams that | |
173 | are insensitive to text boundaries. This means that they may freely split | |
174 | text into smaller texts and /discard empty texts/. The objective, though, is | |
175 | that they should /never concatenate texts/ in order to provide strict upper | |
176 | bounds on memory usage. | |
177 | ||
178 | For example, to stream only the first three lines of 'stdin' to 'stdout' you | |
179 | might write: | |
180 | ||
181 | > import Pipes | |
182 | > import qualified Pipes.Text as Text | |
183 | > import qualified Pipes.Text.IO as Text | |
184 | > import Pipes.Group (takes') | |
185 | > import Lens.Family | |
186 | > | |
187 | > main = runEffect $ takeLines 3 Text.stdin >-> Text.stdout | |
188 | > where | |
189 | > takeLines n = Text.unlines . takes' n . view Text.lines | |
190 | ||
191 | The above program will never bring more than one chunk of text (~ 32 KB) into | |
192 | memory, no matter how long the lines are. | |
193 | ||
82fe661b | 194 | -} |
195 | {- $lenses | |
e4b6dc67 | 196 | As this example shows, one superficial difference from @Data.Text.Lazy@ |
80a490ef | 197 | is that many of the operations, like 'lines', are \'lensified\'; this has a |
198 | number of advantages (where it is possible); in particular it facilitates their | |
199 | use with 'Parser's of Text (in the general <http://hackage.haskell.org/package/pipes-parse-3.0.1/docs/Pipes-Parse-Tutorial.html pipes-parse> | |
200 | sense.) The disadvantage, famously, is that the messages you get for type errors can be | |
201 | a little alarming. The remarks that follow in this section are for non-lens adepts. | |
202 | ||
203 | Each lens exported here, e.g. 'lines', 'chunksOf' or 'splitAt', reduces to the | |
204 | intuitively corresponding function when used with @view@ or @(^.)@. Instead of | |
205 | writing: | |
206 | ||
207 | > splitAt 17 producer | |
208 | ||
209 | as we would with the Prelude or Text functions, we write | |
210 | ||
211 | > view (splitAt 17) producer | |
212 | ||
82fe661b | 213 | or equivalently |
80a490ef | 214 | |
215 | > producer ^. splitAt 17 | |
e4b6dc67 | 216 | |
80a490ef | 217 | This may seem a little indirect, but note that many equivalents of |
218 | @Text -> Text@ functions are exported here as 'Pipe's. Here too we recover the intuitively | |
219 | corresponding functions by prefixing them with @(>->)@. Thus something like | |
e4b6dc67 | 220 | |
221 | > stripLines = Text.unlines . Group.maps (>-> Text.stripStart) . view Text.lines | |
222 | ||
223 | would drop the leading white space from each line. | |
224 | ||
80a490ef | 225 | The lenses in this library are marked as /improper/; this just means that |
e1ed9621 | 226 | they don't admit all the operations of an ideal lens, but only /getting/ and /focusing/. |
80a490ef | 227 | Just for this reason, though, the magnificent complexities of the lens libraries |
228 | are a distraction. The lens combinators to keep in mind, the ones that make sense for | |
229 | our lenses, are @view@ \/ @(^.)@), @over@ \/ @(%~)@ , and @zoom@. | |
230 | ||
79917d53 | 231 | One need only keep in mind that if @l@ is a @Lens'_ a b@, then: |
82fe661b | 232 | |
233 | -} | |
234 | {- $view | |
235 | @view l@ is a function @a -> b@ . Thus @view l a@ (also written @a ^. l@ ) | |
80a490ef | 236 | is the corresponding @b@; as was said above, this function will be exactly the |
237 | function you think it is, given its name. Thus to uppercase the first n characters | |
238 | of a Producer, leaving the rest the same, we could write: | |
239 | ||
240 | ||
241 | > upper n p = do p' <- p ^. Text.splitAt n >-> Text.toUpper | |
242 | > p' | |
82fe661b | 243 | -} |
244 | {- $over | |
245 | @over l@ is a function @(b -> b) -> a -> a@. Thus, given a function that modifies | |
80a490ef | 246 | @b@s, the lens lets us modify an @a@ by applying @f :: b -> b@ to |
247 | the @b@ that we can \"see\" through the lens. So @over l f :: a -> a@ | |
248 | (it can also be written @l %~ f@). | |
249 | For any particular @a@, then, @over l f a@ or @(l %~ f) a@ is a revised @a@. | |
250 | So above we might have written things like these: | |
251 | ||
252 | > stripLines = Text.lines %~ maps (>-> Text.stripStart) | |
253 | > stripLines = over Text.lines (maps (>-> Text.stripStart)) | |
254 | > upper n = Text.splitAt n %~ (>-> Text.toUpper) | |
82fe661b | 255 | |
256 | -} | |
257 | {- $zoom | |
258 | @zoom l@, finally, is a function from a @Parser b m r@ | |
80a490ef | 259 | to a @Parser a m r@ (or more generally a @StateT (Producer b m x) m r@). |
260 | Its use is easiest to see with an decoding lens like 'utf8', which | |
261 | \"sees\" a Text producer hidden inside a ByteString producer: | |
262 | @drawChar@ is a Text parser, returning a @Maybe Char@, @zoom utf8 drawChar@ is | |
263 | a /ByteString/ parser, returning a @Maybe Char@. @drawAll@ is a Parser that returns | |
264 | a list of everything produced from a Producer, leaving only the return value; it would | |
265 | usually be unreasonable to use it. But @zoom (splitAt 17) drawAll@ | |
266 | returns a list of Text chunks containing the first seventeen Chars, and returns the rest of | |
267 | the Text Producer for further parsing. Suppose that we want, inexplicably, to | |
268 | modify the casing of a Text Producer according to any instruction it might | |
269 | contain at the start. Then we might write something like this: | |
270 | ||
271 | > obey :: Monad m => Producer Text m b -> Producer Text m b | |
e1ed9621 | 272 | > obey p = do (ts, p') <- lift $ runStateT (zoom (Text.splitAt 7) drawAll) p |
80a490ef | 273 | > let seven = T.concat ts |
274 | > case T.toUpper seven of | |
275 | > "TOUPPER" -> p' >-> Text.toUpper | |
276 | > "TOLOWER" -> p' >-> Text.toLower | |
277 | > _ -> do yield seven | |
278 | > p' | |
279 | ||
e1ed9621 | 280 | |
281 | > >>> let doc = each ["toU","pperTh","is document.\n"] | |
282 | > >>> runEffect $ obey doc >-> Text.stdout | |
283 | > THIS DOCUMENT. | |
284 | ||
80a490ef | 285 | The purpose of exporting lenses is the mental economy achieved with this three-way |
286 | applicability. That one expression, e.g. @lines@ or @splitAt 17@ can have these | |
287 | three uses is no more surprising than that a pipe can act as a function modifying | |
288 | the output of a producer, namely by using @>->@ to its left: @producer >-> pipe@ | |
289 | -- but can /also/ modify the inputs to a consumer by using @>->@ to its right: | |
290 | @pipe >-> consumer@ | |
291 | ||
292 | The three functions, @view@ \/ @(^.)@, @over@ \/ @(%~)@ and @zoom@ are supplied by | |
293 | both <http://hackage.haskell.org/package/lens lens> and | |
e4b6dc67 | 294 | <http://hackage.haskell.org/package/lens-family lens-family> The use of 'zoom' is explained |
295 | in <http://hackage.haskell.org/package/pipes-parse-3.0.1/docs/Pipes-Parse-Tutorial.html Pipes.Parse.Tutorial> | |
80a490ef | 296 | and to some extent in the @Pipes.Text.Encoding@ module here. |
e4b6dc67 | 297 | |
82fe661b | 298 | -} |
299 | {- $special | |
e4b6dc67 | 300 | These simple 'lines' examples reveal a more important difference from @Data.Text.Lazy@ . |
301 | This is in the types that are most closely associated with our central text type, | |
302 | @Producer Text m r@. In @Data.Text@ and @Data.Text.Lazy@ we find functions like | |
303 | ||
304 | > splitAt :: Int -> Text -> (Text, Text) | |
305 | > lines :: Text -> [Text] | |
306 | > chunksOf :: Int -> Text -> [Text] | |
307 | ||
308 | which relate a Text with a pair of Texts or a list of Texts. | |
309 | The corresponding functions here (taking account of \'lensification\') are | |
310 | ||
311 | > view . splitAt :: (Monad m, Integral n) => n -> Producer Text m r -> Producer Text m (Producer Text m r) | |
312 | > view lines :: Monad m => Producer Text m r -> FreeT (Producer Text m) m r | |
313 | > view . chunksOf :: (Monad m, Integral n) => n -> Producer Text m r -> FreeT (Producer Text m) m r | |
314 | ||
315 | Some of the types may be more readable if you imagine that we have introduced | |
316 | our own type synonyms | |
317 | ||
318 | > type Text m r = Producer T.Text m r | |
319 | > type Texts m r = FreeT (Producer T.Text m) m r | |
320 | ||
321 | Then we would think of the types above as | |
322 | ||
323 | > view . splitAt :: (Monad m, Integral n) => n -> Text m r -> Text m (Text m r) | |
324 | > view lines :: (Monad m) => Text m r -> Texts m r | |
325 | > view . chunksOf :: (Monad m, Integral n) => n -> Text m r -> Texts m r | |
326 | ||
327 | which brings one closer to the types of the similar functions in @Data.Text.Lazy@ | |
328 | ||
329 | In the type @Producer Text m (Producer Text m r)@ the second | |
330 | element of the \'pair\' of effectful Texts cannot simply be retrieved | |
331 | with something like 'snd'. This is an \'effectful\' pair, and one must work | |
332 | through the effects of the first element to arrive at the second Text stream, even | |
333 | if you are proposing to throw the Text in the first element away. | |
334 | Note that we use Control.Monad.join to fuse the pair back together, since it specializes to | |
335 | ||
336 | > join :: Monad m => Producer Text m (Producer m r) -> Producer m r | |
337 | ||
e1ed9621 | 338 | The return type of 'lines', 'words', 'chunksOf' and the other /splitter/ functions, |
e4b6dc67 | 339 | @FreeT (Producer m Text) m r@ -- our @Texts m r@ -- is the type of (effectful) |
340 | lists of (effectful) texts. The type @([Text],r)@ might be seen to gather | |
341 | together things of the forms: | |
342 | ||
343 | > r | |
344 | > (Text,r) | |
345 | > (Text, (Text, r)) | |
346 | > (Text, (Text, (Text, r))) | |
347 | > (Text, (Text, (Text, (Text, r)))) | |
348 | > ... | |
349 | ||
80a490ef | 350 | (We might also have identified the sum of those types with @Free ((,) Text) r@ |
351 | -- or, more absurdly, @FreeT ((,) Text) Identity r@.) | |
352 | ||
353 | Similarly, our type @Texts m r@, or @FreeT (Text m) m r@ -- in fact called | |
354 | @FreeT (Producer Text m) m r@ here -- encompasses all the members of the sequence: | |
e4b6dc67 | 355 | |
356 | > m r | |
80a490ef | 357 | > Text m r |
358 | > Text m (Text m r) | |
359 | > Text m (Text m (Text m r)) | |
360 | > Text m (Text m (Text m (Text m r))) | |
e4b6dc67 | 361 | > ... |
362 | ||
80a490ef | 363 | We might have used a more specialized type in place of @FreeT (Producer a m) m r@, |
364 | or indeed of @FreeT (Producer Text m) m r@, but it is clear that the correct | |
365 | result type of 'lines' will be isomorphic to @FreeT (Producer Text m) m r@ . | |
366 | ||
e4b6dc67 | 367 | One might think that |
368 | ||
79917d53 | 369 | > lines :: Monad m => Lens'_ (Producer Text m r) (FreeT (Producer Text m) m r) |
e4b6dc67 | 370 | > view . lines :: Monad m => Producer Text m r -> FreeT (Producer Text m) m r |
371 | ||
372 | should really have the type | |
373 | ||
374 | > lines :: Monad m => Pipe Text Text m r | |
375 | ||
376 | as e.g. 'toUpper' does. But this would spoil the control we are | |
377 | attempting to maintain over the size of chunks. It is in fact just | |
378 | as unreasonable to want such a pipe as to want | |
379 | ||
380 | > Data.Text.Lazy.lines :: Text -> Text | |
381 | ||
382 | to 'rechunk' the strict Text chunks inside the lazy Text to respect | |
383 | line boundaries. In fact we have | |
384 | ||
385 | > Data.Text.Lazy.lines :: Text -> [Text] | |
386 | > Prelude.lines :: String -> [String] | |
387 | ||
388 | where the elements of the list are themselves lazy Texts or Strings; the use | |
389 | of @FreeT (Producer Text m) m r@ is simply the 'effectful' version of this. | |
390 | ||
391 | The @Pipes.Group@ module, which can generally be imported without qualification, | |
e1ed9621 | 392 | provides many functions for working with things of type @FreeT (Producer a m) m r@. |
80a490ef | 393 | In particular it conveniently exports the constructors for @FreeT@ and the associated |
394 | @FreeF@ type -- a fancy form of @Either@, namely | |
e4b6dc67 | 395 | |
80a490ef | 396 | > data FreeF f a b = Pure a | Free (f b) |
397 | ||
398 | for pattern-matching. Consider the implementation of the 'words' function, or | |
399 | of the part of the lens that takes us to the words; it is compact but exhibits many | |
400 | of the points under discussion, including explicit handling of the @FreeT@ and @FreeF@ | |
401 | constuctors. Keep in mind that | |
402 | ||
403 | > newtype FreeT f m a = FreeT (m (FreeF f a (FreeT f m a))) | |
404 | > next :: Monad m => Producer a m r -> m (Either r (a, Producer a m r)) | |
405 | ||
406 | Thus the @do@ block after the @FreeT@ constructor is in the base monad, e.g. 'IO' or 'Identity'; | |
407 | the later subordinate block, opened by the @Free@ constructor, is in the @Producer@ monad: | |
408 | ||
409 | > words :: Monad m => Producer Text m r -> FreeT (Producer Text m) m r | |
410 | > words p = FreeT $ do -- With 'next' we will inspect p's first chunk, excluding spaces; | |
411 | > x <- next (p >-> dropWhile isSpace) -- note that 'dropWhile isSpace' is a pipe, and is thus *applied* with '>->'. | |
412 | > return $ case x of -- We use 'return' and so need something of type 'FreeF (Text m) r (Texts m r)' | |
413 | > Left r -> Pure r -- 'Left' means we got no Text chunk, but only the return value; so we are done. | |
414 | > Right (txt, p') -> Free $ do -- If we get a chunk and the rest of the producer, p', we enter the 'Producer' monad | |
415 | > p'' <- view (break isSpace) -- When we apply 'break isSpace', we get a Producer that returns a Producer; | |
416 | > (yield txt >> p') -- so here we yield everything up to the next space, and get the rest back. | |
417 | > return (words p'') -- We then carry on with the rest, which is likely to begin with space. | |
418 | ||
419 | -} | |
e4b6dc67 | 420 | |
91727d11 | 421 | -- | Convert a lazy 'TL.Text' into a 'Producer' of strict 'Text's |
422 | fromLazy :: (Monad m) => TL.Text -> Producer' Text m () | |
79917d53 | 423 | fromLazy = TL.foldrChunks (\e a -> yield e >> a) (return ()) |
ca6f90a0 | 424 | {-# INLINE fromLazy #-} |
91727d11 | 425 | |
1677dc12 | 426 | |
d199072b | 427 | (^.) :: a -> ((b -> Constant b b) -> (a -> Constant b a)) -> b |
428 | a ^. lens = getConstant (lens Constant a) | |
429 | ||
1677dc12 | 430 | |
91727d11 | 431 | -- | Apply a transformation to each 'Char' in the stream |
432 | map :: (Monad m) => (Char -> Char) -> Pipe Text Text m r | |
433 | map f = P.map (T.map f) | |
434 | {-# INLINABLE map #-} | |
435 | ||
ff38b9f0 | 436 | {-# RULES "p >-> map f" forall p f . |
437 | p >-> map f = for p (\txt -> yield (T.map f txt)) | |
438 | #-} | |
439 | ||
31f41a5d | 440 | -- | Map a function over the characters of a text stream and concatenate the results |
91727d11 | 441 | concatMap |
442 | :: (Monad m) => (Char -> Text) -> Pipe Text Text m r | |
443 | concatMap f = P.map (T.concatMap f) | |
444 | {-# INLINABLE concatMap #-} | |
445 | ||
ff38b9f0 | 446 | {-# RULES "p >-> concatMap f" forall p f . |
447 | p >-> concatMap f = for p (\txt -> yield (T.concatMap f txt)) | |
448 | #-} | |
7faef8bc | 449 | |
ff38b9f0 | 450 | |
c0343bc9 | 451 | -- | Transform a Pipe of 'String's into one of 'Text' chunks |
7faef8bc | 452 | pack :: Monad m => Pipe String Text m r |
453 | pack = P.map T.pack | |
454 | {-# INLINEABLE pack #-} | |
455 | ||
ff38b9f0 | 456 | {-# RULES "p >-> pack" forall p . |
457 | p >-> pack = for p (\txt -> yield (T.pack txt)) | |
458 | #-} | |
459 | ||
460 | -- | Transform a Pipes of 'Text' chunks into one of 'String's | |
7faef8bc | 461 | unpack :: Monad m => Pipe Text String m r |
d4732515 | 462 | unpack = for cat (\t -> yield (T.unpack t)) |
7faef8bc | 463 | {-# INLINEABLE unpack #-} |
464 | ||
ff38b9f0 | 465 | {-# RULES "p >-> unpack" forall p . |
466 | p >-> unpack = for p (\txt -> yield (T.unpack txt)) | |
467 | #-} | |
d4732515 | 468 | |
b0d86a59 | 469 | -- | @toCaseFold@, @toLower@, @toUpper@ and @stripStart@ are standard 'Text' utilities, |
470 | -- here acting as 'Text' pipes, rather as they would on a lazy text | |
a4913c42 | 471 | toCaseFold :: Monad m => Pipe Text Text m r |
7faef8bc | 472 | toCaseFold = P.map T.toCaseFold |
473 | {-# INLINEABLE toCaseFold #-} | |
474 | ||
ff38b9f0 | 475 | {-# RULES "p >-> toCaseFold" forall p . |
476 | p >-> toCaseFold = for p (\txt -> yield (T.toCaseFold txt)) | |
477 | #-} | |
478 | ||
479 | ||
c0343bc9 | 480 | -- | lowercase incoming 'Text' |
a4913c42 | 481 | toLower :: Monad m => Pipe Text Text m r |
7faef8bc | 482 | toLower = P.map T.toLower |
483 | {-# INLINEABLE toLower #-} | |
484 | ||
ff38b9f0 | 485 | {-# RULES "p >-> toLower" forall p . |
486 | p >-> toLower = for p (\txt -> yield (T.toLower txt)) | |
487 | #-} | |
488 | ||
c0343bc9 | 489 | -- | uppercase incoming 'Text' |
c70edb9d | 490 | toUpper :: Monad m => Pipe Text Text m r |
7faef8bc | 491 | toUpper = P.map T.toUpper |
492 | {-# INLINEABLE toUpper #-} | |
493 | ||
ff38b9f0 | 494 | {-# RULES "p >-> toUpper" forall p . |
495 | p >-> toUpper = for p (\txt -> yield (T.toUpper txt)) | |
496 | #-} | |
497 | ||
c0343bc9 | 498 | -- | Remove leading white space from an incoming succession of 'Text's |
7faef8bc | 499 | stripStart :: Monad m => Pipe Text Text m r |
500 | stripStart = do | |
501 | chunk <- await | |
502 | let text = T.stripStart chunk | |
503 | if T.null text | |
504 | then stripStart | |
b0d86a59 | 505 | else do yield text |
506 | cat | |
7faef8bc | 507 | {-# INLINEABLE stripStart #-} |
508 | ||
31f41a5d | 509 | -- | @(take n)@ only allows @n@ individual characters to pass; |
510 | -- contrast @Pipes.Prelude.take@ which would let @n@ chunks pass. | |
91727d11 | 511 | take :: (Monad m, Integral a) => a -> Pipe Text Text m () |
512 | take n0 = go n0 where | |
513 | go n | |
514 | | n <= 0 = return () | |
515 | | otherwise = do | |
31f41a5d | 516 | txt <- await |
517 | let len = fromIntegral (T.length txt) | |
91727d11 | 518 | if (len > n) |
31f41a5d | 519 | then yield (T.take (fromIntegral n) txt) |
91727d11 | 520 | else do |
31f41a5d | 521 | yield txt |
91727d11 | 522 | go (n - len) |
523 | {-# INLINABLE take #-} | |
524 | ||
31f41a5d | 525 | -- | @(drop n)@ drops the first @n@ characters |
91727d11 | 526 | drop :: (Monad m, Integral a) => a -> Pipe Text Text m r |
527 | drop n0 = go n0 where | |
528 | go n | |
529 | | n <= 0 = cat | |
530 | | otherwise = do | |
31f41a5d | 531 | txt <- await |
532 | let len = fromIntegral (T.length txt) | |
91727d11 | 533 | if (len >= n) |
534 | then do | |
31f41a5d | 535 | yield (T.drop (fromIntegral n) txt) |
91727d11 | 536 | cat |
537 | else go (n - len) | |
538 | {-# INLINABLE drop #-} | |
539 | ||
31f41a5d | 540 | -- | Take characters until they fail the predicate |
91727d11 | 541 | takeWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m () |
542 | takeWhile predicate = go | |
543 | where | |
544 | go = do | |
31f41a5d | 545 | txt <- await |
546 | let (prefix, suffix) = T.span predicate txt | |
91727d11 | 547 | if (T.null suffix) |
548 | then do | |
31f41a5d | 549 | yield txt |
91727d11 | 550 | go |
551 | else yield prefix | |
552 | {-# INLINABLE takeWhile #-} | |
553 | ||
31f41a5d | 554 | -- | Drop characters until they fail the predicate |
91727d11 | 555 | dropWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r |
556 | dropWhile predicate = go where | |
557 | go = do | |
31f41a5d | 558 | txt <- await |
559 | case T.findIndex (not . predicate) txt of | |
91727d11 | 560 | Nothing -> go |
561 | Just i -> do | |
31f41a5d | 562 | yield (T.drop i txt) |
91727d11 | 563 | cat |
564 | {-# INLINABLE dropWhile #-} | |
565 | ||
566 | -- | Only allows 'Char's to pass if they satisfy the predicate | |
567 | filter :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r | |
568 | filter predicate = P.map (T.filter predicate) | |
569 | {-# INLINABLE filter #-} | |
570 | ||
ff38b9f0 | 571 | {-# RULES "p >-> filter q" forall p q . |
572 | p >-> filter q = for p (\txt -> yield (T.filter q txt)) | |
573 | #-} | |
574 | ||
31f41a5d | 575 | -- | Strict left scan over the characters |
91727d11 | 576 | scan |
577 | :: (Monad m) | |
578 | => (Char -> Char -> Char) -> Char -> Pipe Text Text m r | |
11645cdc GG |
579 | scan step begin = do |
580 | yield (T.singleton begin) | |
581 | go begin | |
91727d11 | 582 | where |
31f41a5d | 583 | go c = do |
584 | txt <- await | |
585 | let txt' = T.scanl step c txt | |
586 | c' = T.last txt' | |
11645cdc | 587 | yield (T.tail txt') |
31f41a5d | 588 | go c' |
91727d11 | 589 | {-# INLINABLE scan #-} |
590 | ||
591 | {-| Fold a pure 'Producer' of strict 'Text's into a lazy | |
592 | 'TL.Text' | |
593 | -} | |
594 | toLazy :: Producer Text Identity () -> TL.Text | |
595 | toLazy = TL.fromChunks . P.toList | |
596 | {-# INLINABLE toLazy #-} | |
597 | ||
598 | {-| Fold an effectful 'Producer' of strict 'Text's into a lazy | |
599 | 'TL.Text' | |
600 | ||
601 | Note: 'toLazyM' is not an idiomatic use of @pipes@, but I provide it for | |
602 | simple testing purposes. Idiomatic @pipes@ style consumes the chunks | |
603 | immediately as they are generated instead of loading them all into memory. | |
604 | -} | |
605 | toLazyM :: (Monad m) => Producer Text m () -> m TL.Text | |
606 | toLazyM = liftM TL.fromChunks . P.toListM | |
607 | {-# INLINABLE toLazyM #-} | |
608 | ||
31f41a5d | 609 | -- | Reduce the text stream using a strict left fold over characters |
64e03122 | 610 | foldChars |
91727d11 | 611 | :: Monad m |
612 | => (x -> Char -> x) -> x -> (x -> r) -> Producer Text m () -> m r | |
64e03122 | 613 | foldChars step begin done = P.fold (T.foldl' step) begin done |
1677dc12 | 614 | {-# INLINABLE foldChars #-} |
91727d11 | 615 | |
616 | -- | Retrieve the first 'Char' | |
617 | head :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
618 | head = go | |
619 | where | |
620 | go p = do | |
621 | x <- nextChar p | |
622 | case x of | |
623 | Left _ -> return Nothing | |
31f41a5d | 624 | Right (c, _) -> return (Just c) |
91727d11 | 625 | {-# INLINABLE head #-} |
626 | ||
627 | -- | Retrieve the last 'Char' | |
628 | last :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
629 | last = go Nothing | |
630 | where | |
631 | go r p = do | |
632 | x <- next p | |
633 | case x of | |
634 | Left () -> return r | |
31f41a5d | 635 | Right (txt, p') -> |
636 | if (T.null txt) | |
91727d11 | 637 | then go r p' |
31f41a5d | 638 | else go (Just $ T.last txt) p' |
91727d11 | 639 | {-# INLINABLE last #-} |
640 | ||
641 | -- | Determine if the stream is empty | |
642 | null :: (Monad m) => Producer Text m () -> m Bool | |
643 | null = P.all T.null | |
644 | {-# INLINABLE null #-} | |
645 | ||
62e8521c | 646 | -- | Count the number of characters in the stream |
91727d11 | 647 | length :: (Monad m, Num n) => Producer Text m () -> m n |
31f41a5d | 648 | length = P.fold (\n txt -> n + fromIntegral (T.length txt)) 0 id |
91727d11 | 649 | {-# INLINABLE length #-} |
650 | ||
651 | -- | Fold that returns whether 'M.Any' received 'Char's satisfy the predicate | |
652 | any :: (Monad m) => (Char -> Bool) -> Producer Text m () -> m Bool | |
653 | any predicate = P.any (T.any predicate) | |
654 | {-# INLINABLE any #-} | |
655 | ||
656 | -- | Fold that returns whether 'M.All' received 'Char's satisfy the predicate | |
657 | all :: (Monad m) => (Char -> Bool) -> Producer Text m () -> m Bool | |
658 | all predicate = P.all (T.all predicate) | |
659 | {-# INLINABLE all #-} | |
660 | ||
62e8521c | 661 | -- | Return the maximum 'Char' within a text stream |
91727d11 | 662 | maximum :: (Monad m) => Producer Text m () -> m (Maybe Char) |
663 | maximum = P.fold step Nothing id | |
664 | where | |
31f41a5d | 665 | step mc txt = |
666 | if (T.null txt) | |
667 | then mc | |
668 | else Just $ case mc of | |
669 | Nothing -> T.maximum txt | |
670 | Just c -> max c (T.maximum txt) | |
91727d11 | 671 | {-# INLINABLE maximum #-} |
672 | ||
62e8521c | 673 | -- | Return the minimum 'Char' within a text stream (surely very useful!) |
91727d11 | 674 | minimum :: (Monad m) => Producer Text m () -> m (Maybe Char) |
675 | minimum = P.fold step Nothing id | |
676 | where | |
31f41a5d | 677 | step mc txt = |
678 | if (T.null txt) | |
679 | then mc | |
680 | else case mc of | |
681 | Nothing -> Just (T.minimum txt) | |
682 | Just c -> Just (min c (T.minimum txt)) | |
91727d11 | 683 | {-# INLINABLE minimum #-} |
684 | ||
91727d11 | 685 | -- | Find the first element in the stream that matches the predicate |
686 | find | |
687 | :: (Monad m) | |
688 | => (Char -> Bool) -> Producer Text m () -> m (Maybe Char) | |
689 | find predicate p = head (p >-> filter predicate) | |
690 | {-# INLINABLE find #-} | |
691 | ||
62e8521c | 692 | -- | Index into a text stream |
91727d11 | 693 | index |
694 | :: (Monad m, Integral a) | |
695 | => a-> Producer Text m () -> m (Maybe Char) | |
696 | index n p = head (p >-> drop n) | |
697 | {-# INLINABLE index #-} | |
698 | ||
63ea9ffd | 699 | |
31f41a5d | 700 | -- | Store a tally of how many segments match the given 'Text' |
701 | count :: (Monad m, Num n) => Text -> Producer Text m () -> m n | |
702 | count c p = P.fold (+) 0 id (p >-> P.map (fromIntegral . T.count c)) | |
703 | {-# INLINABLE count #-} | |
704 | ||
9e9bb0ce | 705 | |
1a83ae4e | 706 | -- | Consume the first character from a stream of 'Text' |
707 | -- | |
708 | -- 'next' either fails with a 'Left' if the 'Producer' has no more characters or | |
709 | -- succeeds with a 'Right' providing the next character and the remainder of the | |
710 | -- 'Producer'. | |
9e9bb0ce | 711 | |
9e9bb0ce | 712 | nextChar |
713 | :: (Monad m) | |
714 | => Producer Text m r | |
715 | -> m (Either r (Char, Producer Text m r)) | |
716 | nextChar = go | |
717 | where | |
718 | go p = do | |
719 | x <- next p | |
720 | case x of | |
721 | Left r -> return (Left r) | |
722 | Right (txt, p') -> case (T.uncons txt) of | |
723 | Nothing -> go p' | |
724 | Just (c, txt') -> return (Right (c, yield txt' >> p')) | |
725 | {-# INLINABLE nextChar #-} | |
726 | ||
1a83ae4e | 727 | -- | Draw one 'Char' from a stream of 'Text', returning 'Left' if the 'Producer' is empty |
728 | ||
9e9bb0ce | 729 | drawChar :: (Monad m) => Parser Text m (Maybe Char) |
730 | drawChar = do | |
731 | x <- PP.draw | |
732 | case x of | |
733 | Nothing -> return Nothing | |
734 | Just txt -> case (T.uncons txt) of | |
735 | Nothing -> drawChar | |
736 | Just (c, txt') -> do | |
737 | PP.unDraw txt' | |
738 | return (Just c) | |
739 | {-# INLINABLE drawChar #-} | |
740 | ||
741 | -- | Push back a 'Char' onto the underlying 'Producer' | |
742 | unDrawChar :: (Monad m) => Char -> Parser Text m () | |
743 | unDrawChar c = modify (yield (T.singleton c) >>) | |
744 | {-# INLINABLE unDrawChar #-} | |
745 | ||
746 | {-| 'peekChar' checks the first 'Char' in the stream, but uses 'unDrawChar' to | |
747 | push the 'Char' back | |
748 | ||
749 | > peekChar = do | |
750 | > x <- drawChar | |
751 | > case x of | |
752 | > Left _ -> return () | |
753 | > Right c -> unDrawChar c | |
754 | > return x | |
1a83ae4e | 755 | |
9e9bb0ce | 756 | -} |
1a83ae4e | 757 | |
9e9bb0ce | 758 | peekChar :: (Monad m) => Parser Text m (Maybe Char) |
759 | peekChar = do | |
760 | x <- drawChar | |
761 | case x of | |
762 | Nothing -> return () | |
763 | Just c -> unDrawChar c | |
764 | return x | |
765 | {-# INLINABLE peekChar #-} | |
766 | ||
767 | {-| Check if the underlying 'Producer' has no more characters | |
768 | ||
769 | Note that this will skip over empty 'Text' chunks, unlike | |
770 | 'PP.isEndOfInput' from @pipes-parse@, which would consider | |
771 | an empty 'Text' a valid bit of input. | |
772 | ||
773 | > isEndOfChars = liftM isLeft peekChar | |
774 | -} | |
775 | isEndOfChars :: (Monad m) => Parser Text m Bool | |
776 | isEndOfChars = do | |
777 | x <- peekChar | |
778 | return (case x of | |
779 | Nothing -> True | |
780 | Just _-> False ) | |
781 | {-# INLINABLE isEndOfChars #-} | |
782 | ||
783 | ||
31f41a5d | 784 | -- | Splits a 'Producer' after the given number of characters |
91727d11 | 785 | splitAt |
786 | :: (Monad m, Integral n) | |
787 | => n | |
d199072b | 788 | -> Lens'_ (Producer Text m r) |
789 | (Producer Text m (Producer Text m r)) | |
9e9bb0ce | 790 | splitAt n0 k p0 = fmap join (k (go n0 p0)) |
91727d11 | 791 | where |
792 | go 0 p = return p | |
793 | go n p = do | |
794 | x <- lift (next p) | |
795 | case x of | |
796 | Left r -> return (return r) | |
31f41a5d | 797 | Right (txt, p') -> do |
798 | let len = fromIntegral (T.length txt) | |
91727d11 | 799 | if (len <= n) |
800 | then do | |
31f41a5d | 801 | yield txt |
91727d11 | 802 | go (n - len) p' |
803 | else do | |
31f41a5d | 804 | let (prefix, suffix) = T.splitAt (fromIntegral n) txt |
91727d11 | 805 | yield prefix |
806 | return (yield suffix >> p') | |
807 | {-# INLINABLE splitAt #-} | |
808 | ||
91727d11 | 809 | |
1a83ae4e | 810 | -- | Split a text stream in two, producing the longest |
811 | -- consecutive group of characters that satisfies the predicate | |
812 | -- and returning the rest | |
813 | ||
91727d11 | 814 | span |
815 | :: (Monad m) | |
816 | => (Char -> Bool) | |
d199072b | 817 | -> Lens'_ (Producer Text m r) |
818 | (Producer Text m (Producer Text m r)) | |
9e9bb0ce | 819 | span predicate k p0 = fmap join (k (go p0)) |
91727d11 | 820 | where |
821 | go p = do | |
822 | x <- lift (next p) | |
823 | case x of | |
824 | Left r -> return (return r) | |
31f41a5d | 825 | Right (txt, p') -> do |
826 | let (prefix, suffix) = T.span predicate txt | |
91727d11 | 827 | if (T.null suffix) |
828 | then do | |
31f41a5d | 829 | yield txt |
91727d11 | 830 | go p' |
831 | else do | |
832 | yield prefix | |
833 | return (yield suffix >> p') | |
834 | {-# INLINABLE span #-} | |
835 | ||
1a83ae4e | 836 | {-| Split a text stream in two, producing the longest |
62e8521c | 837 | consecutive group of characters that don't satisfy the predicate |
91727d11 | 838 | -} |
839 | break | |
840 | :: (Monad m) | |
841 | => (Char -> Bool) | |
d199072b | 842 | -> Lens'_ (Producer Text m r) |
843 | (Producer Text m (Producer Text m r)) | |
91727d11 | 844 | break predicate = span (not . predicate) |
845 | {-# INLINABLE break #-} | |
846 | ||
9e9bb0ce | 847 | {-| Improper lens that splits after the first group of equivalent Chars, as |
848 | defined by the given equivalence relation | |
849 | -} | |
850 | groupBy | |
851 | :: (Monad m) | |
852 | => (Char -> Char -> Bool) | |
d199072b | 853 | -> Lens'_ (Producer Text m r) |
854 | (Producer Text m (Producer Text m r)) | |
9e9bb0ce | 855 | groupBy equals k p0 = fmap join (k ((go p0))) where |
856 | go p = do | |
857 | x <- lift (next p) | |
858 | case x of | |
859 | Left r -> return (return r) | |
860 | Right (txt, p') -> case T.uncons txt of | |
861 | Nothing -> go p' | |
862 | Just (c, _) -> (yield txt >> p') ^. span (equals c) | |
863 | {-# INLINABLE groupBy #-} | |
864 | ||
865 | -- | Improper lens that splits after the first succession of identical 'Char' s | |
866 | group :: Monad m | |
79917d53 | 867 | => Lens'_ (Producer Text m r) |
9e9bb0ce | 868 | (Producer Text m (Producer Text m r)) |
869 | group = groupBy (==) | |
870 | {-# INLINABLE group #-} | |
871 | ||
872 | {-| Improper lens that splits a 'Producer' after the first word | |
873 | ||
874 | Unlike 'words', this does not drop leading whitespace | |
875 | -} | |
876 | word :: (Monad m) | |
d199072b | 877 | => Lens'_ (Producer Text m r) |
878 | (Producer Text m (Producer Text m r)) | |
9e9bb0ce | 879 | word k p0 = fmap join (k (to p0)) |
880 | where | |
881 | to p = do | |
882 | p' <- p^.span isSpace | |
883 | p'^.break isSpace | |
884 | {-# INLINABLE word #-} | |
885 | ||
886 | ||
887 | line :: (Monad m) | |
d199072b | 888 | => Lens'_ (Producer Text m r) |
889 | (Producer Text m (Producer Text m r)) | |
9e9bb0ce | 890 | line = break (== '\n') |
891 | ||
892 | {-# INLINABLE line #-} | |
893 | ||
894 | ||
895 | -- | Intersperse a 'Char' in between the characters of stream of 'Text' | |
896 | intersperse | |
897 | :: (Monad m) => Char -> Producer Text m r -> Producer Text m r | |
898 | intersperse c = go0 | |
899 | where | |
900 | go0 p = do | |
901 | x <- lift (next p) | |
902 | case x of | |
903 | Left r -> return r | |
904 | Right (txt, p') -> do | |
905 | yield (T.intersperse c txt) | |
906 | go1 p' | |
907 | go1 p = do | |
908 | x <- lift (next p) | |
909 | case x of | |
910 | Left r -> return r | |
911 | Right (txt, p') -> do | |
912 | yield (T.singleton c) | |
913 | yield (T.intersperse c txt) | |
914 | go1 p' | |
915 | {-# INLINABLE intersperse #-} | |
916 | ||
917 | ||
918 | ||
919 | -- | Improper isomorphism between a 'Producer' of 'ByteString's and 'Word8's | |
79917d53 | 920 | packChars :: Monad m => Iso'_ (Producer Char m x) (Producer Text m x) |
9e9bb0ce | 921 | packChars = Data.Profunctor.dimap to (fmap from) |
922 | where | |
923 | -- to :: Monad m => Producer Char m x -> Producer Text m x | |
7ed76745 | 924 | to p = PG.folds step id done (p^.PG.chunksOf defaultChunkSize) |
9e9bb0ce | 925 | |
926 | step diffAs c = diffAs . (c:) | |
927 | ||
928 | done diffAs = T.pack (diffAs []) | |
929 | ||
930 | -- from :: Monad m => Producer Text m x -> Producer Char m x | |
931 | from p = for p (each . T.unpack) | |
79917d53 | 932 | |
9e9bb0ce | 933 | {-# INLINABLE packChars #-} |
934 | ||
79917d53 | 935 | defaultChunkSize :: Int |
936 | defaultChunkSize = 16384 - (sizeOf (undefined :: Int) `shiftL` 1) | |
0f8c6f1b | 937 | |
938 | -- | Split a text stream into 'FreeT'-delimited text streams of fixed size | |
939 | chunksOf | |
940 | :: (Monad m, Integral n) | |
d199072b | 941 | => n -> Lens'_ (Producer Text m r) |
942 | (FreeT (Producer Text m) m r) | |
0f8c6f1b | 943 | chunksOf n k p0 = fmap concats (k (FreeT (go p0))) |
944 | where | |
945 | go p = do | |
946 | x <- next p | |
947 | return $ case x of | |
7ed76745 | 948 | Left r -> Pure r |
949 | Right (txt, p') -> Free $ do | |
0f8c6f1b | 950 | p'' <- (yield txt >> p') ^. splitAt n |
7ed76745 | 951 | return $ FreeT (go p'') |
0f8c6f1b | 952 | {-# INLINABLE chunksOf #-} |
953 | ||
954 | ||
62e8521c | 955 | {-| Split a text stream into sub-streams delimited by characters that satisfy the |
91727d11 | 956 | predicate |
957 | -} | |
1677dc12 | 958 | splitsWith |
91727d11 | 959 | :: (Monad m) |
960 | => (Char -> Bool) | |
961 | -> Producer Text m r | |
7ed76745 | 962 | -> FreeT (Producer Text m) m r |
963 | splitsWith predicate p0 = FreeT (go0 p0) | |
91727d11 | 964 | where |
965 | go0 p = do | |
966 | x <- next p | |
967 | case x of | |
7ed76745 | 968 | Left r -> return (Pure r) |
31f41a5d | 969 | Right (txt, p') -> |
970 | if (T.null txt) | |
91727d11 | 971 | then go0 p' |
7ed76745 | 972 | else return $ Free $ do |
9e9bb0ce | 973 | p'' <- (yield txt >> p') ^. span (not . predicate) |
7ed76745 | 974 | return $ FreeT (go1 p'') |
91727d11 | 975 | go1 p = do |
976 | x <- nextChar p | |
977 | return $ case x of | |
7ed76745 | 978 | Left r -> Pure r |
979 | Right (_, p') -> Free $ do | |
9e9bb0ce | 980 | p'' <- p' ^. span (not . predicate) |
7ed76745 | 981 | return $ FreeT (go1 p'') |
1677dc12 | 982 | {-# INLINABLE splitsWith #-} |
91727d11 | 983 | |
31f41a5d | 984 | -- | Split a text stream using the given 'Char' as the delimiter |
0f8c6f1b | 985 | splits :: (Monad m) |
d199072b | 986 | => Char |
987 | -> Lens'_ (Producer Text m r) | |
988 | (FreeT (Producer Text m) m r) | |
0f8c6f1b | 989 | splits c k p = |
7ed76745 | 990 | fmap (PG.intercalates (yield (T.singleton c))) (k (splitsWith (c ==) p)) |
0f8c6f1b | 991 | {-# INLINABLE splits #-} |
992 | ||
993 | {-| Isomorphism between a stream of 'Text' and groups of equivalent 'Char's , using the | |
994 | given equivalence relation | |
995 | -} | |
996 | groupsBy | |
997 | :: Monad m | |
998 | => (Char -> Char -> Bool) | |
d199072b | 999 | -> Lens'_ (Producer Text m x) (FreeT (Producer Text m) m x) |
7ed76745 | 1000 | groupsBy equals k p0 = fmap concats (k (FreeT (go p0))) where |
0f8c6f1b | 1001 | go p = do x <- next p |
7ed76745 | 1002 | case x of Left r -> return (Pure r) |
0f8c6f1b | 1003 | Right (bs, p') -> case T.uncons bs of |
1004 | Nothing -> go p' | |
7ed76745 | 1005 | Just (c, _) -> do return $ Free $ do |
0f8c6f1b | 1006 | p'' <- (yield bs >> p')^.span (equals c) |
7ed76745 | 1007 | return $ FreeT (go p'') |
0f8c6f1b | 1008 | {-# INLINABLE groupsBy #-} |
1009 | ||
1010 | ||
1011 | -- | Like 'groupsBy', where the equality predicate is ('==') | |
1012 | groups | |
1013 | :: Monad m | |
d199072b | 1014 | => Lens'_ (Producer Text m x) (FreeT (Producer Text m) m x) |
0f8c6f1b | 1015 | groups = groupsBy (==) |
1016 | {-# INLINABLE groups #-} | |
1017 | ||
91727d11 | 1018 | |
91727d11 | 1019 | |
62e8521c | 1020 | {-| Split a text stream into 'FreeT'-delimited lines |
91727d11 | 1021 | -} |
1022 | lines | |
d199072b | 1023 | :: (Monad m) => Iso'_ (Producer Text m r) (FreeT (Producer Text m) m r) |
1024 | lines = Data.Profunctor.dimap _lines (fmap _unlines) | |
1025 | where | |
1026 | _lines p0 = FreeT (go0 p0) | |
0f8c6f1b | 1027 | where |
1028 | go0 p = do | |
1029 | x <- next p | |
1030 | case x of | |
7ed76745 | 1031 | Left r -> return (Pure r) |
0f8c6f1b | 1032 | Right (txt, p') -> |
1033 | if (T.null txt) | |
1034 | then go0 p' | |
7ed76745 | 1035 | else return $ Free $ go1 (yield txt >> p') |
0f8c6f1b | 1036 | go1 p = do |
1037 | p' <- p ^. break ('\n' ==) | |
7ed76745 | 1038 | return $ FreeT $ do |
0f8c6f1b | 1039 | x <- nextChar p' |
1040 | case x of | |
7ed76745 | 1041 | Left r -> return $ Pure r |
0f8c6f1b | 1042 | Right (_, p'') -> go0 p'' |
d199072b | 1043 | -- _unlines |
1044 | -- :: Monad m | |
1045 | -- => FreeT (Producer Text m) m x -> Producer Text m x | |
1046 | _unlines = concats . PG.maps (<* yield (T.singleton '\n')) | |
1047 | ||
0f8c6f1b | 1048 | |
d199072b | 1049 | {-# INLINABLE lines #-} |
91727d11 | 1050 | |
31f41a5d | 1051 | |
31f41a5d | 1052 | -- | Split a text stream into 'FreeT'-delimited words |
91727d11 | 1053 | words |
79917d53 | 1054 | :: (Monad m) => Iso'_ (Producer Text m r) (FreeT (Producer Text m) m r) |
0f8c6f1b | 1055 | words = Data.Profunctor.dimap go (fmap _unwords) |
91727d11 | 1056 | where |
7ed76745 | 1057 | go p = FreeT $ do |
cf10d6f1 | 1058 | x <- next (p >-> dropWhile isSpace) |
1059 | return $ case x of | |
7ed76745 | 1060 | Left r -> Pure r |
1061 | Right (bs, p') -> Free $ do | |
9e9bb0ce | 1062 | p'' <- (yield bs >> p') ^. break isSpace |
cf10d6f1 | 1063 | return (go p'') |
7ed76745 | 1064 | _unwords = PG.intercalates (yield $ T.singleton ' ') |
0f8c6f1b | 1065 | |
91727d11 | 1066 | {-# INLINABLE words #-} |
1067 | ||
cf10d6f1 | 1068 | |
31f41a5d | 1069 | {-| 'intercalate' concatenates the 'FreeT'-delimited text streams after |
1070 | interspersing a text stream in between them | |
91727d11 | 1071 | -} |
1072 | intercalate | |
1073 | :: (Monad m) | |
1074 | => Producer Text m () | |
1075 | -> FreeT (Producer Text m) m r | |
1076 | -> Producer Text m r | |
1077 | intercalate p0 = go0 | |
1078 | where | |
1079 | go0 f = do | |
7ed76745 | 1080 | x <- lift (runFreeT f) |
91727d11 | 1081 | case x of |
7ed76745 | 1082 | Pure r -> return r |
1083 | Free p -> do | |
91727d11 | 1084 | f' <- p |
1085 | go1 f' | |
1086 | go1 f = do | |
7ed76745 | 1087 | x <- lift (runFreeT f) |
91727d11 | 1088 | case x of |
7ed76745 | 1089 | Pure r -> return r |
1090 | Free p -> do | |
91727d11 | 1091 | p0 |
1092 | f' <- p | |
1093 | go1 f' | |
1094 | {-# INLINABLE intercalate #-} | |
1095 | ||
62e8521c | 1096 | {-| Join 'FreeT'-delimited lines into a text stream |
91727d11 | 1097 | -} |
1098 | unlines | |
d199072b | 1099 | :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r |
1100 | unlines = go | |
1101 | where | |
1102 | go f = do | |
1103 | x <- lift (runFreeT f) | |
1104 | case x of | |
1105 | Pure r -> return r | |
1106 | Free p -> do | |
1107 | f' <- p | |
1108 | yield $ T.singleton '\n' | |
1109 | go f' | |
91727d11 | 1110 | {-# INLINABLE unlines #-} |
1111 | ||
31f41a5d | 1112 | {-| Join 'FreeT'-delimited words into a text stream |
91727d11 | 1113 | -} |
1114 | unwords | |
1115 | :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r | |
7fc48f7c | 1116 | unwords = intercalate (yield $ T.singleton ' ') |
91727d11 | 1117 | {-# INLINABLE unwords #-} |
1118 | ||
91727d11 | 1119 | |
91727d11 | 1120 | {- $reexports |
91727d11 | 1121 | |
1122 | @Data.Text@ re-exports the 'Text' type. | |
1123 | ||
0f8c6f1b | 1124 | @Pipes.Parse@ re-exports 'input', 'concat', 'FreeT' (the type) and the 'Parse' synonym. |
64e03122 | 1125 | -} |
1126 | ||
bbdfd305 | 1127 |