about summary refs log tree commit diff
path: root/users/Profpatsch/my-prelude/MyPrelude.hs
blob: 4ef59c05ffba975966a27cfe76d9c1f6708ebddb (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
{-# LANGUAGE GHC2021 #-}
{-# LANGUAGE ImplicitParams #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# OPTIONS_GHC -fexpose-all-unfoldings #-}

module MyPrelude
  ( -- * Text conversions
    Text,
    ByteString,
    Word8,
    fmt,
    textToString,
    stringToText,
    showToText,
    textToBytesUtf8,
    textToBytesUtf8Lazy,
    bytesToTextUtf8,
    bytesToTextUtf8Lazy,
    bytesToTextUtf8Lenient,
    bytesToTextUtf8LenientLazy,
    bytesToTextUtf8Unsafe,
    bytesToTextUtf8UnsafeLazy,
    toStrict,
    toLazy,
    toStrictBytes,
    toLazyBytes,
    charToWordUnsafe,

    -- * IO
    putStrLn,
    putStderrLn,
    exitWithMessage,

    -- * WIP code
    todo,

    -- * Records
    HasField,

    -- * Control flow
    (&),
    (<&>),
    (<|>),
    foldMap1,
    foldMap',
    join,
    when,
    unless,
    guard,
    ExceptT,
    runExceptT,
    MonadError,
    throwError,
    MonadIO,
    liftIO,
    MonadReader,
    asks,
    Bifunctor,
    first,
    second,
    bimap,
    both,
    foldMap,
    fold,
    foldl',
    fromMaybe,
    mapMaybe,
    findMaybe,
    Traversable,
    for,
    for_,
    traverse,
    traverse_,
    traverseFold,
    traverseFold1,
    traverseFoldDefault,

    -- * Data types
    Coercible,
    coerce,
    Proxy (Proxy),
    Map,
    annotate,
    Validation (Success, Failure),
    failure,
    successes,
    failures,
    eitherToValidation,
    eitherToListValidation,
    validationToEither,
    These (This, That, These),
    eitherToThese,
    eitherToListThese,
    validationToThese,
    thenThese,
    thenValidate,
    NonEmpty ((:|)),
    singleton,
    nonEmpty,
    nonEmptyDef,
    toList,
    toNonEmptyDefault,
    maximum1,
    minimum1,
    Generic,
    Semigroup,
    sconcat,
    Monoid,
    mconcat,
    ifTrue,
    ifExists,
    Void,
    absurd,
    Identity (Identity, runIdentity),
    Natural,
    intToNatural,
    Contravariant,
    contramap,
    (>$<),
    (>&<),
    Profunctor,
    dimap,
    lmap,
    rmap,
    Semigroupoid,
    Category,
    (>>>),
    (&>>),

    -- * Enum definition
    inverseFunction,
    inverseMap,

    -- * Error handling
    HasCallStack,
    module Data.Error,
  )
where

import Control.Applicative ((<|>))
import Control.Category (Category, (>>>))
import Control.Monad (guard, join, unless, when)
import Control.Monad.Except
  ( ExceptT,
    MonadError,
    runExceptT,
    throwError,
  )
import Control.Monad.IO.Class (MonadIO, liftIO)
import Control.Monad.Identity (Identity (Identity))
import Control.Monad.Reader (MonadReader, asks)
import Data.Bifunctor (Bifunctor, bimap, first, second)
import Data.ByteString
  ( ByteString,
  )
import Data.ByteString.Lazy qualified
import Data.Char qualified
import Data.Coerce (Coercible, coerce)
import Data.Data (Proxy (Proxy))
import Data.Error
import Data.Foldable (Foldable (foldMap', toList), fold, foldl', for_, traverse_)
import Data.Foldable qualified as Foldable
import Data.Function ((&))
import Data.Functor ((<&>))
import Data.Functor.Contravariant (Contravariant (contramap), (>$<))
import Data.Functor.Identity (Identity (runIdentity))
import Data.List.NonEmpty (NonEmpty ((:|)), nonEmpty)
import Data.Map.Strict
  ( Map,
  )
import Data.Map.Strict qualified as Map
import Data.Maybe (fromMaybe, mapMaybe)
import Data.Maybe qualified as Maybe
import Data.Profunctor (Profunctor, dimap, lmap, rmap)
import Data.Semigroup (Max (Max, getMax), Min (Min, getMin), sconcat)
import Data.Semigroup.Foldable (Foldable1 (fold1), foldMap1)
import Data.Semigroup.Traversable (Traversable1)
import Data.Semigroupoid (Semigroupoid (o))
import Data.Text
  ( Text,
  )
import Data.Text qualified
import Data.Text.Encoding qualified
import Data.Text.Encoding.Error qualified
import Data.Text.Lazy qualified
import Data.Text.Lazy.Encoding qualified
import Data.These (These (That, These, This))
import Data.Traversable (for)
import Data.Void (Void, absurd)
import Data.Word (Word8)
import GHC.Exception (errorCallWithCallStackException)
import GHC.Exts (RuntimeRep, TYPE, raise#)
import GHC.Generics (Generic)
import GHC.Natural (Natural)
import GHC.Records (HasField)
import GHC.Stack (HasCallStack)
import PyF (fmt)
import System.Exit qualified
import System.IO qualified
import Validation
  ( Validation (Failure, Success),
    eitherToValidation,
    failure,
    failures,
    successes,
    validationToEither,
  )

-- | Forward-applying 'contramap', like '&'/'$' and '<&>'/'<$>' but for '>$<'.
(>&<) :: Contravariant f => f b -> (a -> b) -> f a
(>&<) = flip contramap

infixl 5 >&<

-- | Forward semigroupoid application. The same as '(>>>)', but 'Semigroupoid' is not a superclass of 'Category' (yet).
--
-- Specialized examples:
--
-- @@
-- for functions : (a -> b) -> (b -> c) -> (a -> c)
-- for Folds: Fold a b -> Fold b c -> Fold a c
-- @@
(&>>) :: Semigroupoid s => s a b -> s b c -> s a c
(&>>) = flip Data.Semigroupoid.o

-- like >>>
infixr 1 &>>

-- | encode a Text to a UTF-8 encoded Bytestring
textToBytesUtf8 :: Text -> ByteString
textToBytesUtf8 = Data.Text.Encoding.encodeUtf8

-- | encode a lazy Text to a UTF-8 encoded lazy Bytestring
textToBytesUtf8Lazy :: Data.Text.Lazy.Text -> Data.ByteString.Lazy.ByteString
textToBytesUtf8Lazy = Data.Text.Lazy.Encoding.encodeUtf8

bytesToTextUtf8 :: ByteString -> Either Error Text
bytesToTextUtf8 = first exceptionToError . Data.Text.Encoding.decodeUtf8'

bytesToTextUtf8Lazy :: Data.ByteString.Lazy.ByteString -> Either Error Data.Text.Lazy.Text
bytesToTextUtf8Lazy = first exceptionToError . Data.Text.Lazy.Encoding.decodeUtf8'

-- | decode a Text from a ByteString that is assumed to be UTF-8 (crash if that is not the case)
bytesToTextUtf8Unsafe :: ByteString -> Text
bytesToTextUtf8Unsafe = Data.Text.Encoding.decodeUtf8

-- | decode a Text from a ByteString that is assumed to be UTF-8 (crash if that is not the case)
bytesToTextUtf8UnsafeLazy :: Data.ByteString.Lazy.ByteString -> Data.Text.Lazy.Text
bytesToTextUtf8UnsafeLazy = Data.Text.Lazy.Encoding.decodeUtf8

-- | decode a Text from a ByteString that is assumed to be UTF-8,
-- replace non-UTF-8 characters with the replacment char U+FFFD.
bytesToTextUtf8Lenient :: Data.ByteString.ByteString -> Data.Text.Text
bytesToTextUtf8Lenient =
  Data.Text.Encoding.decodeUtf8With Data.Text.Encoding.Error.lenientDecode

-- | decode a lazy Text from a lazy ByteString that is assumed to be UTF-8,
-- replace non-UTF-8 characters with the replacment char U+FFFD.
bytesToTextUtf8LenientLazy :: Data.ByteString.Lazy.ByteString -> Data.Text.Lazy.Text
bytesToTextUtf8LenientLazy =
  Data.Text.Lazy.Encoding.decodeUtf8With Data.Text.Encoding.Error.lenientDecode

-- | Make a lazy text strict
toStrict :: Data.Text.Lazy.Text -> Text
toStrict = Data.Text.Lazy.toStrict

-- | Make a strict text lazy
toLazy :: Text -> Data.Text.Lazy.Text
toLazy = Data.Text.Lazy.fromStrict

toStrictBytes :: Data.ByteString.Lazy.ByteString -> ByteString
toStrictBytes = Data.ByteString.Lazy.toStrict

toLazyBytes :: ByteString -> Data.ByteString.Lazy.ByteString
toLazyBytes = Data.ByteString.Lazy.fromStrict

textToString :: Text -> String
textToString = Data.Text.unpack

stringToText :: String -> Text
stringToText = Data.Text.pack

showToText :: (Show a) => a -> Text
showToText = stringToText . show

-- | Unsafe conversion between 'Char' and 'Word8'. This is a no-op and
-- silently truncates to 8 bits Chars > '\255'. It is provided as
-- convenience for ByteString construction.
--
-- Use if you want to get the 'Word8' representation of a character literal.
-- Don’t use on arbitrary characters!
--
-- >>> charToWordUnsafe ','
-- 44
charToWordUnsafe :: Char -> Word8
charToWordUnsafe = fromIntegral . Data.Char.ord
{-# INLINE charToWordUnsafe #-}

-- | Single element in a (non-empty) list.
singleton :: a -> NonEmpty a
singleton a = a :| []

-- | If the given list is empty, use the given default element and return a non-empty list.
nonEmptyDef :: a -> [a] -> NonEmpty a
nonEmptyDef def xs =
  xs & nonEmpty & \case
    Nothing -> def :| []
    Just ne -> ne

-- | Construct a non-empty list, given a default value if the ist list was empty.
toNonEmptyDefault :: a -> [a] -> NonEmpty a
toNonEmptyDefault def xs = case xs of
  [] -> def :| []
  (x : xs') -> x :| xs'

-- | @O(n)@. Get the maximum element from a non-empty structure.
maximum1 :: (Foldable1 f, Ord a) => f a -> a
maximum1 xs = xs & foldMap1 Max & getMax

-- | @O(n)@. Get the minimum element from a non-empty structure.
minimum1 :: (Foldable1 f, Ord a) => f a -> a
minimum1 xs = xs & foldMap1 Min & getMin

-- | Annotate a 'Maybe' with an error message and turn it into an 'Either'.
annotate :: err -> Maybe a -> Either err a
annotate err = \case
  Nothing -> Left err
  Just a -> Right a

-- | Map the same function over both sides of a Bifunctor (e.g. a tuple).
both :: Bifunctor bi => (a -> b) -> bi a a -> bi b b
both f = bimap f f

-- | Find the first element for which pred returns `Just a`, and return the `a`.
--
-- Example:
-- @
-- >>> :set -XTypeApplications
-- >>> import qualified Text.Read
--
-- >>> findMaybe (Text.Read.readMaybe @Int) ["foo"]
-- Nothing
-- >>> findMaybe (Text.Read.readMaybe @Int) ["foo", "34.40", "34", "abc"]
-- Just 34
findMaybe :: Foldable t => (a -> Maybe b) -> t a -> Maybe b
findMaybe mPred list =
  let pred' x = Maybe.isJust $ mPred x
   in case Foldable.find pred' list of
        Just a -> mPred a
        Nothing -> Nothing

-- | Like 'eitherToValidation', but puts the Error side into a NonEmpty list
-- to make it combine with other validations.
eitherToListValidation :: Either a c -> Validation (NonEmpty a) c
eitherToListValidation = first singleton . eitherToValidation

-- | Convert an 'Either' to a 'These'.
eitherToThese :: Either err a -> These err a
eitherToThese (Left err) = This err
eitherToThese (Right a) = That a

-- | Like 'eitherToThese', but puts the Error side into a NonEmpty list
-- to make it combine with other theses.
eitherToListThese :: Either err a -> These (NonEmpty err) a
eitherToListThese (Left e) = This (singleton e)
eitherToListThese (Right a) = That a

-- | Convert a 'Validation' to a 'These'.
validationToThese :: Validation err a -> These err a
validationToThese (Failure err) = This err
validationToThese (Success a) = That a

-- | Nested '>>=' of a These inside some other @m@.
--
-- Use if you want to collect errors and successes, and want to chain multiple function returning 'These'.
thenThese ::
  (Monad m, Semigroup err) =>
  (a -> m (These err b)) ->
  m (These err a) ->
  m (These err b)
thenThese f x = do
  th <- x
  join <$> traverse f th

-- | Nested validating bind-like combinator inside some other @m@.
--
-- Use if you want to collect errors, and want to chain multiple functions returning 'Validation'.
thenValidate ::
  (Monad m) =>
  (a -> m (Validation err b)) ->
  m (Validation err a) ->
  m (Validation err b)
thenValidate f x =
  eitherToValidation <$> do
    x' <- validationToEither <$> x
    case x' of
      Left err -> pure $ Left err
      Right a -> validationToEither <$> f a

-- | Put the text to @stderr@.
putStderrLn :: Text -> IO ()
putStderrLn msg =
  System.IO.hPutStrLn System.IO.stderr $ textToString msg

exitWithMessage :: Text -> IO a
exitWithMessage msg = do
  putStderrLn msg
  System.Exit.exitWith $ System.Exit.ExitFailure (-1)

-- | Run some function producing applicative over a traversable data structure,
-- then collect the results in a Monoid.
--
-- Very helpful with side-effecting functions returning @(Validation err a)@:
--
-- @
-- let
--   f :: Text -> IO (Validation (NonEmpty Error) Text)
--   f t = pure $ if t == "foo" then Success t else Failure (singleton ("not foo: " <> t))
--
-- in traverseFold f [ "foo", "bar", "baz" ]
--   == Failure ("not foo bar" :| ["not foo baz"])
-- @
--
-- … since @(Semigroup err => Validation err a)@ is a @Semigroup@/@Monoid@ itself.
traverseFold :: (Applicative ap, Traversable t, Monoid m) => (a -> ap m) -> t a -> ap m
traverseFold f xs =
  -- note: could be weakened to (Foldable t) via `getAp . foldMap (Ap . f)`
  fold <$> traverse f xs
{-# INLINE traverseFold #-}

-- | Like 'traverseFold', but fold over a semigroup instead of a Monoid, by providing a starting element.
traverseFoldDefault :: (Applicative ap, Traversable t, Semigroup m) => m -> (a -> ap m) -> t a -> ap m
traverseFoldDefault def f xs = foldDef def <$> traverse f xs
  where
    foldDef = foldr (<>)
{-# INLINE traverseFoldDefault #-}

-- | Same as 'traverseFold', but with a 'Semigroup' and 'Traversable1' restriction.
traverseFold1 :: (Applicative ap, Traversable1 t, Semigroup s) => (a -> ap s) -> t a -> ap s
-- note: cannot be weakened to (Foldable1 t) because there is no `Ap` for Semigroup (No `Apply` typeclass)
traverseFold1 f xs = fold1 <$> traverse f xs
{-# INLINE traverseFold1 #-}

-- | Use this in places where the code is still to be implemented.
--
-- It always type-checks and will show a warning at compile time if it was forgotten in the code.
--
-- Use instead of 'error' and 'undefined' for code that hasn’t been written.
--
-- Uses the same trick as https://hackage.haskell.org/package/protolude-0.3.0/docs/src/Protolude.Error.html#error
{-# WARNING todo "'todo' (undefined code) remains in code" #-}
todo :: forall (r :: RuntimeRep). forall (a :: TYPE r). HasCallStack => a
todo = raise# (errorCallWithCallStackException "This code was not yet implemented: TODO" ?callStack)

-- | Convert an integer to a 'Natural' if possible
--
-- Named the same as the function from "GHC.Natural", but does not crash.
intToNatural :: Integral a => a -> Maybe Natural
intToNatural i =
  if i < 0
    then Nothing
    else Just $ fromIntegral i

-- | @inverseFunction f@ creates a function that is the inverse of a given function
-- @f@. It does so by constructing 'M.Map' internally for each value @f a@. The
-- implementation makes sure that the 'M.Map' is constructed only once and then
-- shared for every call.
--
-- __Memory usage note:__ don't inverse functions that have types like 'Int'
-- as their result. In this case the created 'M.Map' will have huge size.
--
-- The complexity of reversed mapping is \(\mathcal{O}(\log n)\).
--
-- __Performance note:__ make sure to specialize monomorphic type of your functions
-- that use 'inverseFunction' to avoid 'M.Map' reconstruction.
--
-- One of the common 'inverseFunction' use-case is inverting the 'show' or a 'show'-like
-- function.
--
-- >>> data Color = Red | Green | Blue deriving (Show, Enum, Bounded)
-- >>> parse = inverseFunction show :: String -> Maybe Color
-- >>> parse "Red"
-- Just Red
-- >>> parse "Black"
-- Nothing
--
-- __Correctness note:__ 'inverseFunction' expects /injective function/ as its argument,
-- i.e. the function must map distinct arguments to distinct values.
--
-- Typical usage of this function looks like this:
--
-- @
-- __data__ GhcVer
--    = Ghc802
--    | Ghc822
--    | Ghc844
--    | Ghc865
--    | Ghc881
--    __deriving__ ('Eq', 'Ord', 'Show', 'Enum', 'Bounded')
--
-- showGhcVer :: GhcVer -> 'Text'
-- showGhcVer = \\__case__
--    Ghc802 -> "8.0.2"
--    Ghc822 -> "8.2.2"
--    Ghc844 -> "8.4.4"
--    Ghc865 -> "8.6.5"
--    Ghc881 -> "8.8.1"
--
-- parseGhcVer :: 'Text' -> 'Maybe' GhcVer
-- parseGhcVer = 'inverseFunction' showGhcVer
--
-- Taken from relude’s @Relude.Extra.Enum@.
inverseFunction ::
  forall a k.
  (Bounded a, Enum a, Ord k) =>
  (a -> k) ->
  (k -> Maybe a)
inverseFunction f k = Map.lookup k $ inverseMap f

-- | Like `inverseFunction`, but instead of returning the function
-- it returns a mapping from all possible outputs to their possible inputs.
--
-- This has the same restrictions of 'inverseFunction'.
inverseMap ::
  forall a k.
  (Bounded a, Enum a, Ord k) =>
  (a -> k) ->
  Map k a
inverseMap f =
  universe
    <&> (\a -> (f a, a))
    & Map.fromList
  where
    universe :: [a]
    universe = [minBound .. maxBound]

-- | If the predicate is true, return the @m@, else 'mempty'.
--
-- This can be used (together with `ifExists`) to e.g. create lists with optional elements:
--
-- >>> import Data.Monoid (Sum(..))
--
-- >>> :{ mconcat [
--   ifTrue (1 == 1) [1],
--   [2, 3, 4],
--   ifTrue False [5],
-- ]
-- :}
-- [1,2,3,4]
--
-- Or any other Monoid:
--
-- >>> mconcat [ Sum 1, ifTrue (1 == 1) (Sum 2), Sum 3 ]

-- Sum {getSum = 6}

ifTrue :: Monoid m => Bool -> m -> m
ifTrue pred' m = if pred' then m else mempty

-- | If the given @Maybe@ is @Just@, return the @m@, else return mempty.

-- This can be used (together with `ifTrue`) to e.g. create lists with optional elements:
--
-- >>> import Data.Monoid (Sum(..))
--
-- >>> :{ mconcat [
--   ifExists (Just [1]),
--   [2, 3, 4],
--   ifExists Nothing,
-- ]
-- :}
-- [1,2,3,4]
--
-- Or any other Monoid:
--
-- >>> mconcat [ Sum 1, ifExists (Just (Sum 2)), Sum 3 ]

-- Sum {getSum = 6}

ifExists :: Monoid m => Maybe m -> m
ifExists = fold