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
|
{-# LANGUAGE BlockArguments #-}
{-# LANGUAGE DoAndIfThenElse #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE RecordWildCards #-}
module Language.Haskell.Stylish.Step.Data
( Config(..)
, defaultConfig
, Indent(..)
, MaxColumns(..)
, step
) where
--------------------------------------------------------------------------------
import Prelude hiding (init)
--------------------------------------------------------------------------------
import Control.Monad (forM_, unless, when)
import Data.Function ((&))
import Data.Functor ((<&>))
import Data.List (sortBy)
import Data.Maybe (listToMaybe)
--------------------------------------------------------------------------------
import ApiAnnotation (AnnotationComment)
import BasicTypes (LexicalFixity (..))
import GHC.Hs.Decls (ConDecl (..),
DerivStrategy (..),
HsDataDefn (..), HsDecl (..),
HsDerivingClause (..),
NewOrData (..),
TyClDecl (..))
import GHC.Hs.Extension (GhcPs, NoExtField (..),
noExtCon)
import GHC.Hs.Types (ConDeclField (..),
ForallVisFlag (..),
HsConDetails (..), HsContext,
HsImplicitBndrs (..),
HsTyVarBndr (..),
HsType (..), LHsQTyVars (..))
import RdrName (RdrName)
import SrcLoc (GenLocated (..), Located,
RealLocated)
--------------------------------------------------------------------------------
import Language.Haskell.Stylish.Block
import Language.Haskell.Stylish.Editor
import Language.Haskell.Stylish.GHC
import Language.Haskell.Stylish.Module
import Language.Haskell.Stylish.Printer
import Language.Haskell.Stylish.Step
data Indent
= SameLine
| Indent !Int
deriving (Show, Eq)
data MaxColumns
= MaxColumns !Int
| NoMaxColumns
deriving (Show, Eq)
data Config = Config
{ cEquals :: !Indent
-- ^ Indent between type constructor and @=@ sign (measured from column 0)
, cFirstField :: !Indent
-- ^ Indent between data constructor and @{@ line (measured from column with data constructor name)
, cFieldComment :: !Int
-- ^ Indent between column with @{@ and start of field line comment (this line has @cFieldComment = 2@)
, cDeriving :: !Int
-- ^ Indent before @deriving@ lines (measured from column 0)
, cBreakEnums :: !Bool
-- ^ Break enums by newlines and follow the above rules
, cBreakSingleConstructors :: !Bool
-- ^ Break single constructors when enabled, e.g. @Indent 2@ will not cause newline after @=@
, cVia :: !Indent
-- ^ Indentation between @via@ clause and start of deriving column start
, cCurriedContext :: !Bool
-- ^ If true, use curried context. E.g: @allValues :: Enum a => Bounded a => Proxy a -> [a]@
, cSortDeriving :: !Bool
-- ^ If true, will sort type classes in a @deriving@ list.
, cMaxColumns :: !MaxColumns
} deriving (Show)
-- | TODO: pass in MaxColumns?
defaultConfig :: Config
defaultConfig = Config
{ cEquals = Indent 4
, cFirstField = Indent 4
, cFieldComment = 2
, cDeriving = 4
, cBreakEnums = True
, cBreakSingleConstructors = False
, cVia = Indent 4
, cSortDeriving = True
, cMaxColumns = NoMaxColumns
, cCurriedContext = False
}
step :: Config -> Step
step cfg = makeStep "Data" \ls m -> applyChanges (changes m) ls
where
changes :: Module -> [ChangeLine]
changes m = fmap (formatDataDecl cfg m) (dataDecls m)
dataDecls :: Module -> [Located DataDecl]
dataDecls = queryModule \case
L pos (TyClD _ (DataDecl _ name tvars fixity defn)) -> pure . L pos $ MkDataDecl
{ dataDeclName = name
, dataTypeVars = tvars
, dataDefn = defn
, dataFixity = fixity
}
_ -> []
type ChangeLine = Change String
formatDataDecl :: Config -> Module -> Located DataDecl -> ChangeLine
formatDataDecl cfg@Config{..} m ldecl@(L declPos decl) =
change originalDeclBlock (const printedDecl)
where
relevantComments :: [RealLocated AnnotationComment]
relevantComments
= moduleComments m
& rawComments
& dropBeforeAndAfter ldecl
defn = dataDefn decl
originalDeclBlock =
Block (getStartLineUnsafe ldecl) (getEndLineUnsafe ldecl)
printerConfig = PrinterConfig
{ columns = case cMaxColumns of
NoMaxColumns -> Nothing
MaxColumns n -> Just n
}
printedDecl = runPrinter_ printerConfig relevantComments m do
putText (newOrData decl)
space
putName decl
when (isGADT decl) (space >> putText "where")
when (hasConstructors decl) do
breakLineBeforeEq <- case (cEquals, cFirstField) of
(_, Indent x) | isEnum decl && cBreakEnums -> do
putEolComment declPos
newline >> spaces x
pure True
(_, _) | not (isNewtype decl) && singleConstructor decl && not cBreakSingleConstructors ->
False <$ space
(Indent x, _)
| isEnum decl && not cBreakEnums -> False <$ space
| otherwise -> do
putEolComment declPos
newline >> spaces x
pure True
(SameLine, _) -> False <$ space
lineLengthAfterEq <- fmap (+2) getCurrentLineLength
if isEnum decl && not cBreakEnums then
putText "=" >> space >> putUnbrokenEnum cfg decl
else if isNewtype decl then
putText "=" >> space >> forM_ (dd_cons defn) (putNewtypeConstructor cfg)
else
case dd_cons defn of
[] -> pure ()
lcon@(L pos _) : consRest -> do
when breakLineBeforeEq do
removeCommentTo pos >>= mapM_ \c -> putComment c >> consIndent lineLengthAfterEq
unless
(isGADT decl)
(putText "=" >> space)
putConstructor cfg lineLengthAfterEq lcon
forM_ consRest \con@(L conPos _) -> do
unless (cFirstField == SameLine) do
removeCommentTo conPos >>= mapM_ \c -> consIndent lineLengthAfterEq >> putComment c
consIndent lineLengthAfterEq
unless
(isGADT decl)
(putText "|" >> space)
putConstructor cfg lineLengthAfterEq con
putEolComment conPos
when (hasDeriving decl) do
if isEnum decl && not cBreakEnums then
space
else do
removeCommentTo (defn & dd_derivs & \(L pos _) -> pos) >>=
mapM_ \c -> newline >> spaces cDeriving >> putComment c
newline
spaces cDeriving
sep (newline >> spaces cDeriving) $ defn & dd_derivs & \(L pos ds) -> ds <&> \d -> do
putAllSpanComments (newline >> spaces cDeriving) pos
putDeriving cfg d
consIndent eqIndent = newline >> case (cEquals, cFirstField) of
(SameLine, SameLine) -> spaces (eqIndent - 2)
(SameLine, Indent y) -> spaces (eqIndent + y - 4)
(Indent x, Indent _) -> spaces x
(Indent x, SameLine) -> spaces x
data DataDecl = MkDataDecl
{ dataDeclName :: Located RdrName
, dataTypeVars :: LHsQTyVars GhcPs
, dataDefn :: HsDataDefn GhcPs
, dataFixity :: LexicalFixity
}
putDeriving :: Config -> Located (HsDerivingClause GhcPs) -> P ()
putDeriving Config{..} (L pos clause) = do
putText "deriving"
forM_ (deriv_clause_strategy clause) \case
L _ StockStrategy -> space >> putText "stock"
L _ AnyclassStrategy -> space >> putText "anyclass"
L _ NewtypeStrategy -> space >> putText "newtype"
L _ (ViaStrategy _) -> pure ()
putCond
withinColumns
oneLinePrint
multilinePrint
forM_ (deriv_clause_strategy clause) \case
L _ (ViaStrategy tp) -> do
case cVia of
SameLine -> space
Indent x -> newline >> spaces (x + cDeriving)
putText "via"
space
putType (getType tp)
_ -> pure ()
putEolComment pos
where
getType = \case
HsIB _ tp -> tp
XHsImplicitBndrs x -> noExtCon x
withinColumns PrinterState{currentLine} =
case cMaxColumns of
MaxColumns maxCols -> length currentLine <= maxCols
NoMaxColumns -> True
oneLinePrint = do
space
putText "("
sep
(comma >> space)
(fmap putOutputable tys)
putText ")"
multilinePrint = do
newline
spaces indentation
putText "("
forM_ headTy \t ->
space >> putOutputable t
forM_ tailTy \t -> do
newline
spaces indentation
comma
space
putOutputable t
newline
spaces indentation
putText ")"
indentation =
cDeriving + case cFirstField of
Indent x -> x
SameLine -> 0
tys
= clause
& deriv_clause_tys
& unLocated
& (if cSortDeriving then sortBy compareOutputable else id)
& fmap hsib_body
headTy =
listToMaybe tys
tailTy =
drop 1 tys
putUnbrokenEnum :: Config -> DataDecl -> P ()
putUnbrokenEnum cfg decl =
sep
(space >> putText "|" >> space)
(fmap (putConstructor cfg 0) . dd_cons . dataDefn $ decl)
putName :: DataDecl -> P ()
putName decl@MkDataDecl{..} =
if isInfix decl then do
forM_ firstTvar (\t -> putOutputable t >> space)
putRdrName dataDeclName
space
forM_ secondTvar putOutputable
else do
putRdrName dataDeclName
forM_ (hsq_explicit dataTypeVars) (\t -> space >> putOutputable t)
where
firstTvar :: Maybe (Located (HsTyVarBndr GhcPs))
firstTvar
= dataTypeVars
& hsq_explicit
& listToMaybe
secondTvar :: Maybe (Located (HsTyVarBndr GhcPs))
secondTvar
= dataTypeVars
& hsq_explicit
& drop 1
& listToMaybe
putConstructor :: Config -> Int -> Located (ConDecl GhcPs) -> P ()
putConstructor cfg consIndent (L _ cons) = case cons of
ConDeclGADT{..} -> do
-- Put argument to constructor first:
case con_args of
PrefixCon _ -> do
sep
(comma >> space)
(fmap putRdrName con_names)
InfixCon arg1 arg2 -> do
putType arg1
space
forM_ con_names putRdrName
space
putType arg2
RecCon _ ->
error . mconcat $
[ "Language.Haskell.Stylish.Step.Data.putConstructor: "
, "encountered a GADT with record constructors, not supported yet"
]
-- Put type of constructor:
space
putText "::"
space
when (unLocated con_forall) do
putText "forall"
space
sep space (fmap putOutputable $ hsq_explicit con_qvars)
dot
space
forM_ con_mb_cxt (putContext cfg . unLocated)
putType con_res_ty
XConDecl x ->
noExtCon x
ConDeclH98{..} ->
case con_args of
InfixCon arg1 arg2 -> do
putType arg1
space
putRdrName con_name
space
putType arg2
PrefixCon xs -> do
putRdrName con_name
unless (null xs) space
sep space (fmap putOutputable xs)
RecCon (L recPos (L posFirst firstArg : args)) -> do
putRdrName con_name
skipToBrace
bracePos <- getCurrentLineLength
putText "{"
let fieldPos = bracePos + 2
space
-- Unless everything's configured to be on the same line, put pending
-- comments
unless (cFirstField cfg == SameLine) do
removeCommentTo posFirst >>= mapM_ \c -> putComment c >> sepDecl bracePos
-- Put first decl field
pad fieldPos >> putConDeclField cfg firstArg
unless (cFirstField cfg == SameLine) (putEolComment posFirst)
-- Put tail decl fields
forM_ args \(L pos arg) -> do
sepDecl bracePos
removeCommentTo pos >>= mapM_ \c ->
spaces (cFieldComment cfg) >> putComment c >> sepDecl bracePos
comma
space
putConDeclField cfg arg
putEolComment pos
-- Print docstr after final field
removeCommentToEnd recPos >>= mapM_ \c ->
sepDecl bracePos >> spaces (cFieldComment cfg) >> putComment c
-- Print whitespace to closing brace
sepDecl bracePos >> putText "}"
RecCon (L _ []) -> do
skipToBrace >> putText "{"
skipToBrace >> putText "}"
where
-- Jump to the first brace of the first record of the first constructor.
skipToBrace = case (cEquals cfg, cFirstField cfg) of
(_, Indent y) | not (cBreakSingleConstructors cfg) -> newline >> spaces y
(SameLine, SameLine) -> space
(Indent x, Indent y) -> newline >> spaces (x + y + 2)
(SameLine, Indent y) -> newline >> spaces (consIndent + y)
(Indent _, SameLine) -> space
-- Jump to the next declaration.
sepDecl bracePos = newline >> spaces case (cEquals cfg, cFirstField cfg) of
(_, Indent y) | not (cBreakSingleConstructors cfg) -> y
(SameLine, SameLine) -> bracePos
(Indent x, Indent y) -> x + y + 2
(SameLine, Indent y) -> bracePos + y - 2
(Indent x, SameLine) -> bracePos + x - 2
putNewtypeConstructor :: Config -> Located (ConDecl GhcPs) -> P ()
putNewtypeConstructor cfg (L _ cons) = case cons of
ConDeclH98{..} ->
putRdrName con_name >> case con_args of
PrefixCon xs -> do
unless (null xs) space
sep space (fmap putOutputable xs)
RecCon (L _ [L _posFirst firstArg]) -> do
space
putText "{"
space
putConDeclField cfg firstArg
space
putText "}"
RecCon (L _ _args) ->
error . mconcat $
[ "Language.Haskell.Stylish.Step.Data.putNewtypeConstructor: "
, "encountered newtype with several arguments"
]
InfixCon {} ->
error . mconcat $
[ "Language.Haskell.Stylish.Step.Data.putNewtypeConstructor: "
, "infix newtype constructor"
]
XConDecl x ->
noExtCon x
ConDeclGADT{} ->
error . mconcat $
[ "Language.Haskell.Stylish.Step.Data.putNewtypeConstructor: "
, "GADT encountered in newtype"
]
putContext :: Config -> HsContext GhcPs -> P ()
putContext Config{..} = suffix (space >> putText "=>" >> space) . \case
[L _ (HsParTy _ tp)] | cCurriedContext ->
putType tp
[ctx] ->
putType ctx
ctxs | cCurriedContext ->
sep (space >> putText "=>" >> space) (fmap putType ctxs)
ctxs ->
parenthesize $ sep (comma >> space) (fmap putType ctxs)
putConDeclField :: Config -> ConDeclField GhcPs -> P ()
putConDeclField cfg = \case
ConDeclField{..} -> do
sep
(comma >> space)
(fmap putOutputable cd_fld_names)
space
putText "::"
space
putType' cfg cd_fld_type
XConDeclField{} ->
error . mconcat $
[ "Language.Haskell.Stylish.Step.Data.putConDeclField: "
, "XConDeclField encountered"
]
-- | A variant of 'putType' that takes 'cCurriedContext' into account
putType' :: Config -> Located (HsType GhcPs) -> P ()
putType' cfg = \case
L _ (HsForAllTy NoExtField vis bndrs tp) -> do
putText "forall"
space
sep space (fmap putOutputable bndrs)
putText
if vis == ForallVis then "->"
else "."
space
putType' cfg tp
L _ (HsQualTy NoExtField ctx tp) -> do
putContext cfg (unLocated ctx)
putType' cfg tp
other -> putType other
newOrData :: DataDecl -> String
newOrData decl = if isNewtype decl then "newtype" else "data"
isGADT :: DataDecl -> Bool
isGADT = any isGADTCons . dd_cons . dataDefn
where
isGADTCons = \case
L _ (ConDeclGADT {}) -> True
_ -> False
isNewtype :: DataDecl -> Bool
isNewtype = (== NewType) . dd_ND . dataDefn
isInfix :: DataDecl -> Bool
isInfix = (== Infix) . dataFixity
isEnum :: DataDecl -> Bool
isEnum = all isUnary . dd_cons . dataDefn
where
isUnary = \case
L _ (ConDeclH98 {..}) -> case con_args of
PrefixCon [] -> True
_ -> False
_ -> False
hasConstructors :: DataDecl -> Bool
hasConstructors = not . null . dd_cons . dataDefn
singleConstructor :: DataDecl -> Bool
singleConstructor = (== 1) . length . dd_cons . dataDefn
hasDeriving :: DataDecl -> Bool
hasDeriving = not . null . unLocated . dd_derivs . dataDefn
|