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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) |
91727d11 | 117 | import qualified Pipes.Prelude as P |
91727d11 | 118 | import Data.Char (isSpace) |
1a83ae4e | 119 | import Data.Word (Word8) |
79917d53 | 120 | import Foreign.Storable (sizeOf) |
121 | import Data.Bits (shiftL) | |
91727d11 | 122 | import Prelude hiding ( |
123 | all, | |
124 | any, | |
125 | break, | |
126 | concat, | |
127 | concatMap, | |
128 | drop, | |
129 | dropWhile, | |
130 | elem, | |
131 | filter, | |
132 | head, | |
133 | last, | |
134 | lines, | |
135 | length, | |
136 | map, | |
137 | maximum, | |
138 | minimum, | |
139 | notElem, | |
140 | null, | |
141 | readFile, | |
142 | span, | |
143 | splitAt, | |
144 | take, | |
145 | takeWhile, | |
146 | unlines, | |
147 | unwords, | |
148 | words, | |
149 | writeFile ) | |
150 | ||
e4b6dc67 | 151 | {- $intro |
e1ed9621 | 152 | This package provides @pipes@ utilities for /text streams/ or /character streams/, |
153 | realized as streams of 'Text' chunks. The individual chunks are uniformly /strict/, | |
154 | and thus you will generally want @Data.Text@ in scope. But the type | |
155 | @Producer Text m r@ ,as we are using it, is a sort of /pipes/ equivalent of the lazy @Text@ type. | |
e4b6dc67 | 156 | |
157 | This particular module provides many functions equivalent in one way or another to | |
158 | the pure functions in | |
159 | <https://hackage.haskell.org/package/text-1.1.0.0/docs/Data-Text-Lazy.html Data.Text.Lazy>. | |
160 | They transform, divide, group and fold text streams. Though @Producer Text m r@ | |
161 | is the type of \'effectful Text\', the functions in this module are \'pure\' | |
162 | in the sense that they are uniformly monad-independent. | |
163 | Simple /IO/ operations are defined in @Pipes.Text.IO@ -- as lazy IO @Text@ | |
164 | operations are in @Data.Text.Lazy.IO@. Inter-operation with @ByteString@ | |
165 | is provided in @Pipes.Text.Encoding@, which parallels @Data.Text.Lazy.Encoding@. | |
166 | ||
167 | The Text type exported by @Data.Text.Lazy@ is basically that of a lazy list of | |
168 | strict Text: the implementation is arranged so that the individual strict 'Text' | |
169 | chunks are kept to a reasonable size; the user is not aware of the divisions | |
170 | between the connected 'Text' chunks. | |
171 | So also here: the functions in this module are designed to operate on streams that | |
172 | are insensitive to text boundaries. This means that they may freely split | |
173 | text into smaller texts and /discard empty texts/. The objective, though, is | |
174 | that they should /never concatenate texts/ in order to provide strict upper | |
175 | bounds on memory usage. | |
176 | ||
177 | For example, to stream only the first three lines of 'stdin' to 'stdout' you | |
178 | might write: | |
179 | ||
180 | > import Pipes | |
181 | > import qualified Pipes.Text as Text | |
182 | > import qualified Pipes.Text.IO as Text | |
183 | > import Pipes.Group (takes') | |
184 | > import Lens.Family | |
185 | > | |
186 | > main = runEffect $ takeLines 3 Text.stdin >-> Text.stdout | |
187 | > where | |
188 | > takeLines n = Text.unlines . takes' n . view Text.lines | |
189 | ||
190 | The above program will never bring more than one chunk of text (~ 32 KB) into | |
191 | memory, no matter how long the lines are. | |
192 | ||
82fe661b | 193 | -} |
194 | {- $lenses | |
e4b6dc67 | 195 | As this example shows, one superficial difference from @Data.Text.Lazy@ |
80a490ef | 196 | is that many of the operations, like 'lines', are \'lensified\'; this has a |
197 | number of advantages (where it is possible); in particular it facilitates their | |
198 | 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> | |
199 | sense.) The disadvantage, famously, is that the messages you get for type errors can be | |
200 | a little alarming. The remarks that follow in this section are for non-lens adepts. | |
201 | ||
202 | Each lens exported here, e.g. 'lines', 'chunksOf' or 'splitAt', reduces to the | |
203 | intuitively corresponding function when used with @view@ or @(^.)@. Instead of | |
204 | writing: | |
205 | ||
206 | > splitAt 17 producer | |
207 | ||
208 | as we would with the Prelude or Text functions, we write | |
209 | ||
210 | > view (splitAt 17) producer | |
211 | ||
82fe661b | 212 | or equivalently |
80a490ef | 213 | |
214 | > producer ^. splitAt 17 | |
e4b6dc67 | 215 | |
80a490ef | 216 | This may seem a little indirect, but note that many equivalents of |
217 | @Text -> Text@ functions are exported here as 'Pipe's. Here too we recover the intuitively | |
218 | corresponding functions by prefixing them with @(>->)@. Thus something like | |
e4b6dc67 | 219 | |
220 | > stripLines = Text.unlines . Group.maps (>-> Text.stripStart) . view Text.lines | |
221 | ||
222 | would drop the leading white space from each line. | |
223 | ||
80a490ef | 224 | The lenses in this library are marked as /improper/; this just means that |
e1ed9621 | 225 | they don't admit all the operations of an ideal lens, but only /getting/ and /focusing/. |
80a490ef | 226 | Just for this reason, though, the magnificent complexities of the lens libraries |
227 | are a distraction. The lens combinators to keep in mind, the ones that make sense for | |
228 | our lenses, are @view@ \/ @(^.)@), @over@ \/ @(%~)@ , and @zoom@. | |
229 | ||
57454c33 | 230 | One need only keep in mind that if @l@ is a @Lens' a b@, then: |
82fe661b | 231 | |
232 | -} | |
233 | {- $view | |
234 | @view l@ is a function @a -> b@ . Thus @view l a@ (also written @a ^. l@ ) | |
80a490ef | 235 | is the corresponding @b@; as was said above, this function will be exactly the |
236 | function you think it is, given its name. Thus to uppercase the first n characters | |
237 | of a Producer, leaving the rest the same, we could write: | |
238 | ||
239 | ||
240 | > upper n p = do p' <- p ^. Text.splitAt n >-> Text.toUpper | |
241 | > p' | |
82fe661b | 242 | -} |
243 | {- $over | |
244 | @over l@ is a function @(b -> b) -> a -> a@. Thus, given a function that modifies | |
80a490ef | 245 | @b@s, the lens lets us modify an @a@ by applying @f :: b -> b@ to |
246 | the @b@ that we can \"see\" through the lens. So @over l f :: a -> a@ | |
247 | (it can also be written @l %~ f@). | |
248 | For any particular @a@, then, @over l f a@ or @(l %~ f) a@ is a revised @a@. | |
249 | So above we might have written things like these: | |
250 | ||
251 | > stripLines = Text.lines %~ maps (>-> Text.stripStart) | |
252 | > stripLines = over Text.lines (maps (>-> Text.stripStart)) | |
253 | > upper n = Text.splitAt n %~ (>-> Text.toUpper) | |
82fe661b | 254 | |
255 | -} | |
256 | {- $zoom | |
257 | @zoom l@, finally, is a function from a @Parser b m r@ | |
80a490ef | 258 | to a @Parser a m r@ (or more generally a @StateT (Producer b m x) m r@). |
259 | Its use is easiest to see with an decoding lens like 'utf8', which | |
260 | \"sees\" a Text producer hidden inside a ByteString producer: | |
261 | @drawChar@ is a Text parser, returning a @Maybe Char@, @zoom utf8 drawChar@ is | |
262 | a /ByteString/ parser, returning a @Maybe Char@. @drawAll@ is a Parser that returns | |
263 | a list of everything produced from a Producer, leaving only the return value; it would | |
264 | usually be unreasonable to use it. But @zoom (splitAt 17) drawAll@ | |
265 | returns a list of Text chunks containing the first seventeen Chars, and returns the rest of | |
266 | the Text Producer for further parsing. Suppose that we want, inexplicably, to | |
267 | modify the casing of a Text Producer according to any instruction it might | |
268 | contain at the start. Then we might write something like this: | |
269 | ||
270 | > obey :: Monad m => Producer Text m b -> Producer Text m b | |
e1ed9621 | 271 | > obey p = do (ts, p') <- lift $ runStateT (zoom (Text.splitAt 7) drawAll) p |
80a490ef | 272 | > let seven = T.concat ts |
273 | > case T.toUpper seven of | |
274 | > "TOUPPER" -> p' >-> Text.toUpper | |
275 | > "TOLOWER" -> p' >-> Text.toLower | |
276 | > _ -> do yield seven | |
277 | > p' | |
278 | ||
e1ed9621 | 279 | |
280 | > >>> let doc = each ["toU","pperTh","is document.\n"] | |
281 | > >>> runEffect $ obey doc >-> Text.stdout | |
282 | > THIS DOCUMENT. | |
283 | ||
80a490ef | 284 | The purpose of exporting lenses is the mental economy achieved with this three-way |
285 | applicability. That one expression, e.g. @lines@ or @splitAt 17@ can have these | |
286 | three uses is no more surprising than that a pipe can act as a function modifying | |
287 | the output of a producer, namely by using @>->@ to its left: @producer >-> pipe@ | |
288 | -- but can /also/ modify the inputs to a consumer by using @>->@ to its right: | |
289 | @pipe >-> consumer@ | |
290 | ||
291 | The three functions, @view@ \/ @(^.)@, @over@ \/ @(%~)@ and @zoom@ are supplied by | |
292 | both <http://hackage.haskell.org/package/lens lens> and | |
e4b6dc67 | 293 | <http://hackage.haskell.org/package/lens-family lens-family> The use of 'zoom' is explained |
294 | in <http://hackage.haskell.org/package/pipes-parse-3.0.1/docs/Pipes-Parse-Tutorial.html Pipes.Parse.Tutorial> | |
80a490ef | 295 | and to some extent in the @Pipes.Text.Encoding@ module here. |
e4b6dc67 | 296 | |
82fe661b | 297 | -} |
298 | {- $special | |
e4b6dc67 | 299 | These simple 'lines' examples reveal a more important difference from @Data.Text.Lazy@ . |
300 | This is in the types that are most closely associated with our central text type, | |
301 | @Producer Text m r@. In @Data.Text@ and @Data.Text.Lazy@ we find functions like | |
302 | ||
303 | > splitAt :: Int -> Text -> (Text, Text) | |
304 | > lines :: Text -> [Text] | |
305 | > chunksOf :: Int -> Text -> [Text] | |
306 | ||
307 | which relate a Text with a pair of Texts or a list of Texts. | |
308 | The corresponding functions here (taking account of \'lensification\') are | |
309 | ||
310 | > view . splitAt :: (Monad m, Integral n) => n -> Producer Text m r -> Producer Text m (Producer Text m r) | |
311 | > view lines :: Monad m => Producer Text m r -> FreeT (Producer Text m) m r | |
312 | > view . chunksOf :: (Monad m, Integral n) => n -> Producer Text m r -> FreeT (Producer Text m) m r | |
313 | ||
314 | Some of the types may be more readable if you imagine that we have introduced | |
315 | our own type synonyms | |
316 | ||
317 | > type Text m r = Producer T.Text m r | |
318 | > type Texts m r = FreeT (Producer T.Text m) m r | |
319 | ||
320 | Then we would think of the types above as | |
321 | ||
322 | > view . splitAt :: (Monad m, Integral n) => n -> Text m r -> Text m (Text m r) | |
323 | > view lines :: (Monad m) => Text m r -> Texts m r | |
324 | > view . chunksOf :: (Monad m, Integral n) => n -> Text m r -> Texts m r | |
325 | ||
326 | which brings one closer to the types of the similar functions in @Data.Text.Lazy@ | |
327 | ||
328 | In the type @Producer Text m (Producer Text m r)@ the second | |
329 | element of the \'pair\' of effectful Texts cannot simply be retrieved | |
330 | with something like 'snd'. This is an \'effectful\' pair, and one must work | |
331 | through the effects of the first element to arrive at the second Text stream, even | |
332 | if you are proposing to throw the Text in the first element away. | |
333 | Note that we use Control.Monad.join to fuse the pair back together, since it specializes to | |
334 | ||
335 | > join :: Monad m => Producer Text m (Producer m r) -> Producer m r | |
336 | ||
e1ed9621 | 337 | The return type of 'lines', 'words', 'chunksOf' and the other /splitter/ functions, |
e4b6dc67 | 338 | @FreeT (Producer m Text) m r@ -- our @Texts m r@ -- is the type of (effectful) |
339 | lists of (effectful) texts. The type @([Text],r)@ might be seen to gather | |
340 | together things of the forms: | |
341 | ||
342 | > r | |
343 | > (Text,r) | |
344 | > (Text, (Text, r)) | |
345 | > (Text, (Text, (Text, r))) | |
346 | > (Text, (Text, (Text, (Text, r)))) | |
347 | > ... | |
348 | ||
80a490ef | 349 | (We might also have identified the sum of those types with @Free ((,) Text) r@ |
350 | -- or, more absurdly, @FreeT ((,) Text) Identity r@.) | |
351 | ||
352 | Similarly, our type @Texts m r@, or @FreeT (Text m) m r@ -- in fact called | |
353 | @FreeT (Producer Text m) m r@ here -- encompasses all the members of the sequence: | |
e4b6dc67 | 354 | |
355 | > m r | |
80a490ef | 356 | > Text m r |
357 | > Text m (Text m r) | |
358 | > Text m (Text m (Text m r)) | |
359 | > Text m (Text m (Text m (Text m r))) | |
e4b6dc67 | 360 | > ... |
361 | ||
80a490ef | 362 | We might have used a more specialized type in place of @FreeT (Producer a m) m r@, |
363 | or indeed of @FreeT (Producer Text m) m r@, but it is clear that the correct | |
364 | result type of 'lines' will be isomorphic to @FreeT (Producer Text m) m r@ . | |
365 | ||
e4b6dc67 | 366 | One might think that |
367 | ||
57454c33 | 368 | > lines :: Monad m => Lens' (Producer Text m r) (FreeT (Producer Text m) m r) |
e4b6dc67 | 369 | > view . lines :: Monad m => Producer Text m r -> FreeT (Producer Text m) m r |
370 | ||
371 | should really have the type | |
372 | ||
373 | > lines :: Monad m => Pipe Text Text m r | |
374 | ||
375 | as e.g. 'toUpper' does. But this would spoil the control we are | |
376 | attempting to maintain over the size of chunks. It is in fact just | |
377 | as unreasonable to want such a pipe as to want | |
378 | ||
379 | > Data.Text.Lazy.lines :: Text -> Text | |
380 | ||
381 | to 'rechunk' the strict Text chunks inside the lazy Text to respect | |
382 | line boundaries. In fact we have | |
383 | ||
384 | > Data.Text.Lazy.lines :: Text -> [Text] | |
385 | > Prelude.lines :: String -> [String] | |
386 | ||
387 | where the elements of the list are themselves lazy Texts or Strings; the use | |
388 | of @FreeT (Producer Text m) m r@ is simply the 'effectful' version of this. | |
389 | ||
390 | The @Pipes.Group@ module, which can generally be imported without qualification, | |
e1ed9621 | 391 | provides many functions for working with things of type @FreeT (Producer a m) m r@. |
80a490ef | 392 | In particular it conveniently exports the constructors for @FreeT@ and the associated |
393 | @FreeF@ type -- a fancy form of @Either@, namely | |
e4b6dc67 | 394 | |
80a490ef | 395 | > data FreeF f a b = Pure a | Free (f b) |
396 | ||
397 | for pattern-matching. Consider the implementation of the 'words' function, or | |
398 | of the part of the lens that takes us to the words; it is compact but exhibits many | |
399 | of the points under discussion, including explicit handling of the @FreeT@ and @FreeF@ | |
400 | constuctors. Keep in mind that | |
401 | ||
402 | > newtype FreeT f m a = FreeT (m (FreeF f a (FreeT f m a))) | |
403 | > next :: Monad m => Producer a m r -> m (Either r (a, Producer a m r)) | |
404 | ||
405 | Thus the @do@ block after the @FreeT@ constructor is in the base monad, e.g. 'IO' or 'Identity'; | |
406 | the later subordinate block, opened by the @Free@ constructor, is in the @Producer@ monad: | |
407 | ||
408 | > words :: Monad m => Producer Text m r -> FreeT (Producer Text m) m r | |
409 | > words p = FreeT $ do -- With 'next' we will inspect p's first chunk, excluding spaces; | |
410 | > x <- next (p >-> dropWhile isSpace) -- note that 'dropWhile isSpace' is a pipe, and is thus *applied* with '>->'. | |
411 | > return $ case x of -- We use 'return' and so need something of type 'FreeF (Text m) r (Texts m r)' | |
412 | > Left r -> Pure r -- 'Left' means we got no Text chunk, but only the return value; so we are done. | |
413 | > Right (txt, p') -> Free $ do -- If we get a chunk and the rest of the producer, p', we enter the 'Producer' monad | |
414 | > p'' <- view (break isSpace) -- When we apply 'break isSpace', we get a Producer that returns a Producer; | |
415 | > (yield txt >> p') -- so here we yield everything up to the next space, and get the rest back. | |
416 | > return (words p'') -- We then carry on with the rest, which is likely to begin with space. | |
417 | ||
418 | -} | |
e4b6dc67 | 419 | |
91727d11 | 420 | -- | Convert a lazy 'TL.Text' into a 'Producer' of strict 'Text's |
421 | fromLazy :: (Monad m) => TL.Text -> Producer' Text m () | |
79917d53 | 422 | fromLazy = TL.foldrChunks (\e a -> yield e >> a) (return ()) |
ca6f90a0 | 423 | {-# INLINE fromLazy #-} |
91727d11 | 424 | |
d199072b | 425 | (^.) :: a -> ((b -> Constant b b) -> (a -> Constant b a)) -> b |
426 | a ^. lens = getConstant (lens Constant a) | |
427 | ||
91727d11 | 428 | -- | Apply a transformation to each 'Char' in the stream |
429 | map :: (Monad m) => (Char -> Char) -> Pipe Text Text m r | |
430 | map f = P.map (T.map f) | |
431 | {-# INLINABLE map #-} | |
432 | ||
31f41a5d | 433 | -- | Map a function over the characters of a text stream and concatenate the results |
91727d11 | 434 | concatMap |
435 | :: (Monad m) => (Char -> Text) -> Pipe Text Text m r | |
436 | concatMap f = P.map (T.concatMap f) | |
437 | {-# INLINABLE concatMap #-} | |
438 | ||
c0343bc9 | 439 | -- | Transform a Pipe of 'String's into one of 'Text' chunks |
7faef8bc | 440 | pack :: Monad m => Pipe String Text m r |
441 | pack = P.map T.pack | |
442 | {-# INLINEABLE pack #-} | |
443 | ||
ff38b9f0 | 444 | -- | Transform a Pipes of 'Text' chunks into one of 'String's |
7faef8bc | 445 | unpack :: Monad m => Pipe Text String m r |
d4732515 | 446 | unpack = for cat (\t -> yield (T.unpack t)) |
7faef8bc | 447 | {-# INLINEABLE unpack #-} |
448 | ||
b0d86a59 | 449 | -- | @toCaseFold@, @toLower@, @toUpper@ and @stripStart@ are standard 'Text' utilities, |
450 | -- here acting as 'Text' pipes, rather as they would on a lazy text | |
a4913c42 | 451 | toCaseFold :: Monad m => Pipe Text Text m r |
7faef8bc | 452 | toCaseFold = P.map T.toCaseFold |
453 | {-# INLINEABLE toCaseFold #-} | |
454 | ||
c0343bc9 | 455 | -- | lowercase incoming 'Text' |
a4913c42 | 456 | toLower :: Monad m => Pipe Text Text m r |
7faef8bc | 457 | toLower = P.map T.toLower |
458 | {-# INLINEABLE toLower #-} | |
459 | ||
c0343bc9 | 460 | -- | uppercase incoming 'Text' |
c70edb9d | 461 | toUpper :: Monad m => Pipe Text Text m r |
7faef8bc | 462 | toUpper = P.map T.toUpper |
463 | {-# INLINEABLE toUpper #-} | |
464 | ||
c0343bc9 | 465 | -- | Remove leading white space from an incoming succession of 'Text's |
7faef8bc | 466 | stripStart :: Monad m => Pipe Text Text m r |
467 | stripStart = do | |
468 | chunk <- await | |
469 | let text = T.stripStart chunk | |
470 | if T.null text | |
471 | then stripStart | |
b0d86a59 | 472 | else do yield text |
473 | cat | |
7faef8bc | 474 | {-# INLINEABLE stripStart #-} |
475 | ||
31f41a5d | 476 | -- | @(take n)@ only allows @n@ individual characters to pass; |
477 | -- contrast @Pipes.Prelude.take@ which would let @n@ chunks pass. | |
91727d11 | 478 | take :: (Monad m, Integral a) => a -> Pipe Text Text m () |
479 | take n0 = go n0 where | |
480 | go n | |
481 | | n <= 0 = return () | |
482 | | otherwise = do | |
31f41a5d | 483 | txt <- await |
484 | let len = fromIntegral (T.length txt) | |
91727d11 | 485 | if (len > n) |
31f41a5d | 486 | then yield (T.take (fromIntegral n) txt) |
91727d11 | 487 | else do |
31f41a5d | 488 | yield txt |
91727d11 | 489 | go (n - len) |
490 | {-# INLINABLE take #-} | |
491 | ||
31f41a5d | 492 | -- | @(drop n)@ drops the first @n@ characters |
91727d11 | 493 | drop :: (Monad m, Integral a) => a -> Pipe Text Text m r |
494 | drop n0 = go n0 where | |
495 | go n | |
496 | | n <= 0 = cat | |
497 | | otherwise = do | |
31f41a5d | 498 | txt <- await |
499 | let len = fromIntegral (T.length txt) | |
91727d11 | 500 | if (len >= n) |
501 | then do | |
31f41a5d | 502 | yield (T.drop (fromIntegral n) txt) |
91727d11 | 503 | cat |
504 | else go (n - len) | |
505 | {-# INLINABLE drop #-} | |
506 | ||
31f41a5d | 507 | -- | Take characters until they fail the predicate |
91727d11 | 508 | takeWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m () |
509 | takeWhile predicate = go | |
510 | where | |
511 | go = do | |
31f41a5d | 512 | txt <- await |
513 | let (prefix, suffix) = T.span predicate txt | |
91727d11 | 514 | if (T.null suffix) |
515 | then do | |
31f41a5d | 516 | yield txt |
91727d11 | 517 | go |
518 | else yield prefix | |
519 | {-# INLINABLE takeWhile #-} | |
520 | ||
31f41a5d | 521 | -- | Drop characters until they fail the predicate |
91727d11 | 522 | dropWhile :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r |
523 | dropWhile predicate = go where | |
524 | go = do | |
31f41a5d | 525 | txt <- await |
526 | case T.findIndex (not . predicate) txt of | |
91727d11 | 527 | Nothing -> go |
528 | Just i -> do | |
31f41a5d | 529 | yield (T.drop i txt) |
91727d11 | 530 | cat |
531 | {-# INLINABLE dropWhile #-} | |
532 | ||
533 | -- | Only allows 'Char's to pass if they satisfy the predicate | |
534 | filter :: (Monad m) => (Char -> Bool) -> Pipe Text Text m r | |
535 | filter predicate = P.map (T.filter predicate) | |
536 | {-# INLINABLE filter #-} | |
537 | ||
31f41a5d | 538 | -- | Strict left scan over the characters |
91727d11 | 539 | scan |
540 | :: (Monad m) | |
541 | => (Char -> Char -> Char) -> Char -> Pipe Text Text m r | |
11645cdc GG |
542 | scan step begin = do |
543 | yield (T.singleton begin) | |
544 | go begin | |
91727d11 | 545 | where |
31f41a5d | 546 | go c = do |
547 | txt <- await | |
548 | let txt' = T.scanl step c txt | |
549 | c' = T.last txt' | |
11645cdc | 550 | yield (T.tail txt') |
31f41a5d | 551 | go c' |
91727d11 | 552 | {-# INLINABLE scan #-} |
553 | ||
554 | {-| Fold a pure 'Producer' of strict 'Text's into a lazy | |
555 | 'TL.Text' | |
556 | -} | |
557 | toLazy :: Producer Text Identity () -> TL.Text | |
558 | toLazy = TL.fromChunks . P.toList | |
559 | {-# INLINABLE toLazy #-} | |
560 | ||
561 | {-| Fold an effectful 'Producer' of strict 'Text's into a lazy | |
562 | 'TL.Text' | |
563 | ||
564 | Note: 'toLazyM' is not an idiomatic use of @pipes@, but I provide it for | |
565 | simple testing purposes. Idiomatic @pipes@ style consumes the chunks | |
566 | immediately as they are generated instead of loading them all into memory. | |
567 | -} | |
568 | toLazyM :: (Monad m) => Producer Text m () -> m TL.Text | |
569 | toLazyM = liftM TL.fromChunks . P.toListM | |
570 | {-# INLINABLE toLazyM #-} | |
571 | ||
31f41a5d | 572 | -- | Reduce the text stream using a strict left fold over characters |
64e03122 | 573 | foldChars |
91727d11 | 574 | :: Monad m |
575 | => (x -> Char -> x) -> x -> (x -> r) -> Producer Text m () -> m r | |
64e03122 | 576 | foldChars step begin done = P.fold (T.foldl' step) begin done |
1677dc12 | 577 | {-# INLINABLE foldChars #-} |
91727d11 | 578 | |
579 | -- | Retrieve the first 'Char' | |
580 | head :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
581 | head = go | |
582 | where | |
583 | go p = do | |
584 | x <- nextChar p | |
585 | case x of | |
586 | Left _ -> return Nothing | |
31f41a5d | 587 | Right (c, _) -> return (Just c) |
91727d11 | 588 | {-# INLINABLE head #-} |
589 | ||
590 | -- | Retrieve the last 'Char' | |
591 | last :: (Monad m) => Producer Text m () -> m (Maybe Char) | |
592 | last = go Nothing | |
593 | where | |
594 | go r p = do | |
595 | x <- next p | |
596 | case x of | |
597 | Left () -> return r | |
31f41a5d | 598 | Right (txt, p') -> |
599 | if (T.null txt) | |
91727d11 | 600 | then go r p' |
31f41a5d | 601 | else go (Just $ T.last txt) p' |
91727d11 | 602 | {-# INLINABLE last #-} |
603 | ||
604 | -- | Determine if the stream is empty | |
605 | null :: (Monad m) => Producer Text m () -> m Bool | |
606 | null = P.all T.null | |
607 | {-# INLINABLE null #-} | |
608 | ||
62e8521c | 609 | -- | Count the number of characters in the stream |
91727d11 | 610 | length :: (Monad m, Num n) => Producer Text m () -> m n |
31f41a5d | 611 | length = P.fold (\n txt -> n + fromIntegral (T.length txt)) 0 id |
91727d11 | 612 | {-# INLINABLE length #-} |
613 | ||
614 | -- | Fold that returns whether 'M.Any' received 'Char's satisfy the predicate | |
615 | any :: (Monad m) => (Char -> Bool) -> Producer Text m () -> m Bool | |
616 | any predicate = P.any (T.any predicate) | |
617 | {-# INLINABLE any #-} | |
618 | ||
619 | -- | Fold that returns whether 'M.All' received 'Char's satisfy the predicate | |
620 | all :: (Monad m) => (Char -> Bool) -> Producer Text m () -> m Bool | |
621 | all predicate = P.all (T.all predicate) | |
622 | {-# INLINABLE all #-} | |
623 | ||
62e8521c | 624 | -- | Return the maximum 'Char' within a text stream |
91727d11 | 625 | maximum :: (Monad m) => Producer Text m () -> m (Maybe Char) |
626 | maximum = P.fold step Nothing id | |
627 | where | |
31f41a5d | 628 | step mc txt = |
629 | if (T.null txt) | |
630 | then mc | |
631 | else Just $ case mc of | |
632 | Nothing -> T.maximum txt | |
633 | Just c -> max c (T.maximum txt) | |
91727d11 | 634 | {-# INLINABLE maximum #-} |
635 | ||
62e8521c | 636 | -- | Return the minimum 'Char' within a text stream (surely very useful!) |
91727d11 | 637 | minimum :: (Monad m) => Producer Text m () -> m (Maybe Char) |
638 | minimum = P.fold step Nothing id | |
639 | where | |
31f41a5d | 640 | step mc txt = |
641 | if (T.null txt) | |
642 | then mc | |
643 | else case mc of | |
644 | Nothing -> Just (T.minimum txt) | |
645 | Just c -> Just (min c (T.minimum txt)) | |
91727d11 | 646 | {-# INLINABLE minimum #-} |
647 | ||
91727d11 | 648 | -- | Find the first element in the stream that matches the predicate |
649 | find | |
650 | :: (Monad m) | |
651 | => (Char -> Bool) -> Producer Text m () -> m (Maybe Char) | |
652 | find predicate p = head (p >-> filter predicate) | |
653 | {-# INLINABLE find #-} | |
654 | ||
62e8521c | 655 | -- | Index into a text stream |
91727d11 | 656 | index |
657 | :: (Monad m, Integral a) | |
658 | => a-> Producer Text m () -> m (Maybe Char) | |
659 | index n p = head (p >-> drop n) | |
660 | {-# INLINABLE index #-} | |
661 | ||
63ea9ffd | 662 | |
31f41a5d | 663 | -- | Store a tally of how many segments match the given 'Text' |
664 | count :: (Monad m, Num n) => Text -> Producer Text m () -> m n | |
665 | count c p = P.fold (+) 0 id (p >-> P.map (fromIntegral . T.count c)) | |
666 | {-# INLINABLE count #-} | |
667 | ||
9e9bb0ce | 668 | |
1a83ae4e | 669 | -- | Consume the first character from a stream of 'Text' |
670 | -- | |
671 | -- 'next' either fails with a 'Left' if the 'Producer' has no more characters or | |
672 | -- succeeds with a 'Right' providing the next character and the remainder of the | |
673 | -- 'Producer'. | |
9e9bb0ce | 674 | |
9e9bb0ce | 675 | nextChar |
676 | :: (Monad m) | |
677 | => Producer Text m r | |
678 | -> m (Either r (Char, Producer Text m r)) | |
679 | nextChar = go | |
680 | where | |
681 | go p = do | |
682 | x <- next p | |
683 | case x of | |
684 | Left r -> return (Left r) | |
685 | Right (txt, p') -> case (T.uncons txt) of | |
686 | Nothing -> go p' | |
687 | Just (c, txt') -> return (Right (c, yield txt' >> p')) | |
688 | {-# INLINABLE nextChar #-} | |
689 | ||
1a83ae4e | 690 | -- | Draw one 'Char' from a stream of 'Text', returning 'Left' if the 'Producer' is empty |
691 | ||
9e9bb0ce | 692 | drawChar :: (Monad m) => Parser Text m (Maybe Char) |
693 | drawChar = do | |
694 | x <- PP.draw | |
695 | case x of | |
696 | Nothing -> return Nothing | |
697 | Just txt -> case (T.uncons txt) of | |
698 | Nothing -> drawChar | |
699 | Just (c, txt') -> do | |
700 | PP.unDraw txt' | |
701 | return (Just c) | |
702 | {-# INLINABLE drawChar #-} | |
703 | ||
704 | -- | Push back a 'Char' onto the underlying 'Producer' | |
705 | unDrawChar :: (Monad m) => Char -> Parser Text m () | |
706 | unDrawChar c = modify (yield (T.singleton c) >>) | |
707 | {-# INLINABLE unDrawChar #-} | |
708 | ||
709 | {-| 'peekChar' checks the first 'Char' in the stream, but uses 'unDrawChar' to | |
710 | push the 'Char' back | |
711 | ||
712 | > peekChar = do | |
713 | > x <- drawChar | |
714 | > case x of | |
715 | > Left _ -> return () | |
716 | > Right c -> unDrawChar c | |
717 | > return x | |
1a83ae4e | 718 | |
9e9bb0ce | 719 | -} |
1a83ae4e | 720 | |
9e9bb0ce | 721 | peekChar :: (Monad m) => Parser Text m (Maybe Char) |
722 | peekChar = do | |
723 | x <- drawChar | |
724 | case x of | |
725 | Nothing -> return () | |
726 | Just c -> unDrawChar c | |
727 | return x | |
728 | {-# INLINABLE peekChar #-} | |
729 | ||
730 | {-| Check if the underlying 'Producer' has no more characters | |
731 | ||
732 | Note that this will skip over empty 'Text' chunks, unlike | |
733 | 'PP.isEndOfInput' from @pipes-parse@, which would consider | |
734 | an empty 'Text' a valid bit of input. | |
735 | ||
736 | > isEndOfChars = liftM isLeft peekChar | |
737 | -} | |
738 | isEndOfChars :: (Monad m) => Parser Text m Bool | |
739 | isEndOfChars = do | |
740 | x <- peekChar | |
741 | return (case x of | |
742 | Nothing -> True | |
743 | Just _-> False ) | |
744 | {-# INLINABLE isEndOfChars #-} | |
745 | ||
746 | ||
31f41a5d | 747 | -- | Splits a 'Producer' after the given number of characters |
91727d11 | 748 | splitAt |
749 | :: (Monad m, Integral n) | |
750 | => n | |
57454c33 | 751 | -> Lens' (Producer Text m r) |
d199072b | 752 | (Producer Text m (Producer Text m r)) |
9e9bb0ce | 753 | splitAt n0 k p0 = fmap join (k (go n0 p0)) |
91727d11 | 754 | where |
755 | go 0 p = return p | |
756 | go n p = do | |
757 | x <- lift (next p) | |
758 | case x of | |
759 | Left r -> return (return r) | |
31f41a5d | 760 | Right (txt, p') -> do |
761 | let len = fromIntegral (T.length txt) | |
91727d11 | 762 | if (len <= n) |
763 | then do | |
31f41a5d | 764 | yield txt |
91727d11 | 765 | go (n - len) p' |
766 | else do | |
31f41a5d | 767 | let (prefix, suffix) = T.splitAt (fromIntegral n) txt |
91727d11 | 768 | yield prefix |
769 | return (yield suffix >> p') | |
770 | {-# INLINABLE splitAt #-} | |
771 | ||
91727d11 | 772 | |
1a83ae4e | 773 | -- | Split a text stream in two, producing the longest |
774 | -- consecutive group of characters that satisfies the predicate | |
775 | -- and returning the rest | |
776 | ||
91727d11 | 777 | span |
778 | :: (Monad m) | |
779 | => (Char -> Bool) | |
57454c33 | 780 | -> Lens' (Producer Text m r) |
d199072b | 781 | (Producer Text m (Producer Text m r)) |
9e9bb0ce | 782 | span predicate k p0 = fmap join (k (go p0)) |
91727d11 | 783 | where |
784 | go p = do | |
785 | x <- lift (next p) | |
786 | case x of | |
787 | Left r -> return (return r) | |
31f41a5d | 788 | Right (txt, p') -> do |
789 | let (prefix, suffix) = T.span predicate txt | |
91727d11 | 790 | if (T.null suffix) |
791 | then do | |
31f41a5d | 792 | yield txt |
91727d11 | 793 | go p' |
794 | else do | |
795 | yield prefix | |
796 | return (yield suffix >> p') | |
797 | {-# INLINABLE span #-} | |
798 | ||
1a83ae4e | 799 | {-| Split a text stream in two, producing the longest |
62e8521c | 800 | consecutive group of characters that don't satisfy the predicate |
91727d11 | 801 | -} |
802 | break | |
803 | :: (Monad m) | |
804 | => (Char -> Bool) | |
57454c33 | 805 | -> Lens' (Producer Text m r) |
d199072b | 806 | (Producer Text m (Producer Text m r)) |
91727d11 | 807 | break predicate = span (not . predicate) |
808 | {-# INLINABLE break #-} | |
809 | ||
9e9bb0ce | 810 | {-| Improper lens that splits after the first group of equivalent Chars, as |
811 | defined by the given equivalence relation | |
812 | -} | |
813 | groupBy | |
814 | :: (Monad m) | |
815 | => (Char -> Char -> Bool) | |
57454c33 | 816 | -> Lens' (Producer Text m r) |
d199072b | 817 | (Producer Text m (Producer Text m r)) |
9e9bb0ce | 818 | groupBy equals k p0 = fmap join (k ((go p0))) where |
819 | go p = do | |
820 | x <- lift (next p) | |
821 | case x of | |
822 | Left r -> return (return r) | |
823 | Right (txt, p') -> case T.uncons txt of | |
824 | Nothing -> go p' | |
825 | Just (c, _) -> (yield txt >> p') ^. span (equals c) | |
826 | {-# INLINABLE groupBy #-} | |
827 | ||
828 | -- | Improper lens that splits after the first succession of identical 'Char' s | |
829 | group :: Monad m | |
57454c33 | 830 | => Lens' (Producer Text m r) |
9e9bb0ce | 831 | (Producer Text m (Producer Text m r)) |
832 | group = groupBy (==) | |
833 | {-# INLINABLE group #-} | |
834 | ||
835 | {-| Improper lens that splits a 'Producer' after the first word | |
836 | ||
837 | Unlike 'words', this does not drop leading whitespace | |
838 | -} | |
839 | word :: (Monad m) | |
57454c33 | 840 | => Lens' (Producer Text m r) |
d199072b | 841 | (Producer Text m (Producer Text m r)) |
9e9bb0ce | 842 | word k p0 = fmap join (k (to p0)) |
843 | where | |
844 | to p = do | |
845 | p' <- p^.span isSpace | |
846 | p'^.break isSpace | |
847 | {-# INLINABLE word #-} | |
848 | ||
849 | ||
850 | line :: (Monad m) | |
57454c33 | 851 | => Lens' (Producer Text m r) |
d199072b | 852 | (Producer Text m (Producer Text m r)) |
9e9bb0ce | 853 | line = break (== '\n') |
854 | ||
855 | {-# INLINABLE line #-} | |
856 | ||
857 | ||
858 | -- | Intersperse a 'Char' in between the characters of stream of 'Text' | |
859 | intersperse | |
860 | :: (Monad m) => Char -> Producer Text m r -> Producer Text m r | |
861 | intersperse c = go0 | |
862 | where | |
863 | go0 p = do | |
864 | x <- lift (next p) | |
865 | case x of | |
866 | Left r -> return r | |
867 | Right (txt, p') -> do | |
868 | yield (T.intersperse c txt) | |
869 | go1 p' | |
870 | go1 p = do | |
871 | x <- lift (next p) | |
872 | case x of | |
873 | Left r -> return r | |
874 | Right (txt, p') -> do | |
875 | yield (T.singleton c) | |
876 | yield (T.intersperse c txt) | |
877 | go1 p' | |
878 | {-# INLINABLE intersperse #-} | |
879 | ||
880 | ||
9e9bb0ce | 881 | -- | Improper isomorphism between a 'Producer' of 'ByteString's and 'Word8's |
79917d53 | 882 | packChars :: Monad m => Iso'_ (Producer Char m x) (Producer Text m x) |
9e9bb0ce | 883 | packChars = Data.Profunctor.dimap to (fmap from) |
884 | where | |
885 | -- to :: Monad m => Producer Char m x -> Producer Text m x | |
7ed76745 | 886 | to p = PG.folds step id done (p^.PG.chunksOf defaultChunkSize) |
9e9bb0ce | 887 | |
888 | step diffAs c = diffAs . (c:) | |
889 | ||
890 | done diffAs = T.pack (diffAs []) | |
891 | ||
892 | -- from :: Monad m => Producer Text m x -> Producer Char m x | |
893 | from p = for p (each . T.unpack) | |
894 | {-# INLINABLE packChars #-} | |
895 | ||
79917d53 | 896 | defaultChunkSize :: Int |
897 | defaultChunkSize = 16384 - (sizeOf (undefined :: Int) `shiftL` 1) | |
0f8c6f1b | 898 | |
899 | -- | Split a text stream into 'FreeT'-delimited text streams of fixed size | |
900 | chunksOf | |
901 | :: (Monad m, Integral n) | |
57454c33 | 902 | => n -> Lens' (Producer Text m r) |
d199072b | 903 | (FreeT (Producer Text m) m r) |
0f8c6f1b | 904 | chunksOf n k p0 = fmap concats (k (FreeT (go p0))) |
905 | where | |
906 | go p = do | |
907 | x <- next p | |
908 | return $ case x of | |
7ed76745 | 909 | Left r -> Pure r |
910 | Right (txt, p') -> Free $ do | |
0f8c6f1b | 911 | p'' <- (yield txt >> p') ^. splitAt n |
7ed76745 | 912 | return $ FreeT (go p'') |
0f8c6f1b | 913 | {-# INLINABLE chunksOf #-} |
914 | ||
915 | ||
62e8521c | 916 | {-| Split a text stream into sub-streams delimited by characters that satisfy the |
91727d11 | 917 | predicate |
918 | -} | |
1677dc12 | 919 | splitsWith |
91727d11 | 920 | :: (Monad m) |
921 | => (Char -> Bool) | |
922 | -> Producer Text m r | |
7ed76745 | 923 | -> FreeT (Producer Text m) m r |
924 | splitsWith predicate p0 = FreeT (go0 p0) | |
91727d11 | 925 | where |
926 | go0 p = do | |
927 | x <- next p | |
928 | case x of | |
7ed76745 | 929 | Left r -> return (Pure r) |
31f41a5d | 930 | Right (txt, p') -> |
931 | if (T.null txt) | |
91727d11 | 932 | then go0 p' |
7ed76745 | 933 | else return $ Free $ do |
9e9bb0ce | 934 | p'' <- (yield txt >> p') ^. span (not . predicate) |
7ed76745 | 935 | return $ FreeT (go1 p'') |
91727d11 | 936 | go1 p = do |
937 | x <- nextChar p | |
938 | return $ case x of | |
7ed76745 | 939 | Left r -> Pure r |
940 | Right (_, p') -> Free $ do | |
9e9bb0ce | 941 | p'' <- p' ^. span (not . predicate) |
7ed76745 | 942 | return $ FreeT (go1 p'') |
1677dc12 | 943 | {-# INLINABLE splitsWith #-} |
91727d11 | 944 | |
31f41a5d | 945 | -- | Split a text stream using the given 'Char' as the delimiter |
0f8c6f1b | 946 | splits :: (Monad m) |
d199072b | 947 | => Char |
57454c33 | 948 | -> Lens' (Producer Text m r) |
d199072b | 949 | (FreeT (Producer Text m) m r) |
0f8c6f1b | 950 | splits c k p = |
7ed76745 | 951 | fmap (PG.intercalates (yield (T.singleton c))) (k (splitsWith (c ==) p)) |
0f8c6f1b | 952 | {-# INLINABLE splits #-} |
953 | ||
954 | {-| Isomorphism between a stream of 'Text' and groups of equivalent 'Char's , using the | |
955 | given equivalence relation | |
956 | -} | |
957 | groupsBy | |
958 | :: Monad m | |
959 | => (Char -> Char -> Bool) | |
57454c33 | 960 | -> Lens' (Producer Text m x) (FreeT (Producer Text m) m x) |
7ed76745 | 961 | groupsBy equals k p0 = fmap concats (k (FreeT (go p0))) where |
0f8c6f1b | 962 | go p = do x <- next p |
7ed76745 | 963 | case x of Left r -> return (Pure r) |
0f8c6f1b | 964 | Right (bs, p') -> case T.uncons bs of |
965 | Nothing -> go p' | |
7ed76745 | 966 | Just (c, _) -> do return $ Free $ do |
0f8c6f1b | 967 | p'' <- (yield bs >> p')^.span (equals c) |
7ed76745 | 968 | return $ FreeT (go p'') |
0f8c6f1b | 969 | {-# INLINABLE groupsBy #-} |
970 | ||
971 | ||
972 | -- | Like 'groupsBy', where the equality predicate is ('==') | |
973 | groups | |
974 | :: Monad m | |
57454c33 | 975 | => Lens' (Producer Text m x) (FreeT (Producer Text m) m x) |
0f8c6f1b | 976 | groups = groupsBy (==) |
977 | {-# INLINABLE groups #-} | |
978 | ||
91727d11 | 979 | |
91727d11 | 980 | |
62e8521c | 981 | {-| Split a text stream into 'FreeT'-delimited lines |
91727d11 | 982 | -} |
983 | lines | |
d199072b | 984 | :: (Monad m) => Iso'_ (Producer Text m r) (FreeT (Producer Text m) m r) |
985 | lines = Data.Profunctor.dimap _lines (fmap _unlines) | |
986 | where | |
987 | _lines p0 = FreeT (go0 p0) | |
0f8c6f1b | 988 | where |
989 | go0 p = do | |
990 | x <- next p | |
991 | case x of | |
7ed76745 | 992 | Left r -> return (Pure r) |
0f8c6f1b | 993 | Right (txt, p') -> |
994 | if (T.null txt) | |
995 | then go0 p' | |
7ed76745 | 996 | else return $ Free $ go1 (yield txt >> p') |
0f8c6f1b | 997 | go1 p = do |
998 | p' <- p ^. break ('\n' ==) | |
7ed76745 | 999 | return $ FreeT $ do |
0f8c6f1b | 1000 | x <- nextChar p' |
1001 | case x of | |
7ed76745 | 1002 | Left r -> return $ Pure r |
0f8c6f1b | 1003 | Right (_, p'') -> go0 p'' |
d199072b | 1004 | -- _unlines |
1005 | -- :: Monad m | |
1006 | -- => FreeT (Producer Text m) m x -> Producer Text m x | |
1007 | _unlines = concats . PG.maps (<* yield (T.singleton '\n')) | |
0f8c6f1b | 1008 | |
d199072b | 1009 | {-# INLINABLE lines #-} |
91727d11 | 1010 | |
31f41a5d | 1011 | |
31f41a5d | 1012 | -- | Split a text stream into 'FreeT'-delimited words |
91727d11 | 1013 | words |
79917d53 | 1014 | :: (Monad m) => Iso'_ (Producer Text m r) (FreeT (Producer Text m) m r) |
0f8c6f1b | 1015 | words = Data.Profunctor.dimap go (fmap _unwords) |
91727d11 | 1016 | where |
7ed76745 | 1017 | go p = FreeT $ do |
cf10d6f1 | 1018 | x <- next (p >-> dropWhile isSpace) |
1019 | return $ case x of | |
7ed76745 | 1020 | Left r -> Pure r |
1021 | Right (bs, p') -> Free $ do | |
9e9bb0ce | 1022 | p'' <- (yield bs >> p') ^. break isSpace |
cf10d6f1 | 1023 | return (go p'') |
7ed76745 | 1024 | _unwords = PG.intercalates (yield $ T.singleton ' ') |
0f8c6f1b | 1025 | |
91727d11 | 1026 | {-# INLINABLE words #-} |
1027 | ||
cf10d6f1 | 1028 | |
31f41a5d | 1029 | {-| 'intercalate' concatenates the 'FreeT'-delimited text streams after |
1030 | interspersing a text stream in between them | |
91727d11 | 1031 | -} |
1032 | intercalate | |
1033 | :: (Monad m) | |
1034 | => Producer Text m () | |
1035 | -> FreeT (Producer Text m) m r | |
1036 | -> Producer Text m r | |
1037 | intercalate p0 = go0 | |
1038 | where | |
1039 | go0 f = do | |
7ed76745 | 1040 | x <- lift (runFreeT f) |
91727d11 | 1041 | case x of |
7ed76745 | 1042 | Pure r -> return r |
1043 | Free p -> do | |
91727d11 | 1044 | f' <- p |
1045 | go1 f' | |
1046 | go1 f = do | |
7ed76745 | 1047 | x <- lift (runFreeT f) |
91727d11 | 1048 | case x of |
7ed76745 | 1049 | Pure r -> return r |
1050 | Free p -> do | |
91727d11 | 1051 | p0 |
1052 | f' <- p | |
1053 | go1 f' | |
1054 | {-# INLINABLE intercalate #-} | |
1055 | ||
62e8521c | 1056 | {-| Join 'FreeT'-delimited lines into a text stream |
91727d11 | 1057 | -} |
1058 | unlines | |
d199072b | 1059 | :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r |
1060 | unlines = go | |
1061 | where | |
1062 | go f = do | |
1063 | x <- lift (runFreeT f) | |
1064 | case x of | |
1065 | Pure r -> return r | |
1066 | Free p -> do | |
1067 | f' <- p | |
1068 | yield $ T.singleton '\n' | |
1069 | go f' | |
91727d11 | 1070 | {-# INLINABLE unlines #-} |
1071 | ||
31f41a5d | 1072 | {-| Join 'FreeT'-delimited words into a text stream |
91727d11 | 1073 | -} |
1074 | unwords | |
1075 | :: (Monad m) => FreeT (Producer Text m) m r -> Producer Text m r | |
7fc48f7c | 1076 | unwords = intercalate (yield $ T.singleton ' ') |
91727d11 | 1077 | {-# INLINABLE unwords #-} |
1078 | ||
91727d11 | 1079 | |
91727d11 | 1080 | {- $reexports |
91727d11 | 1081 | |
1082 | @Data.Text@ re-exports the 'Text' type. | |
1083 | ||
0f8c6f1b | 1084 | @Pipes.Parse@ re-exports 'input', 'concat', 'FreeT' (the type) and the 'Parse' synonym. |
64e03122 | 1085 | -} |
1086 | ||
bbdfd305 | 1087 | |
57454c33 | 1088 | type Lens' a b = forall f . Functor f => (b -> f b) -> (a -> f a) |