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brittany/src/Language/Haskell/Brittany/Internal/Layouters/Decl.hs

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{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeApplications #-}
module Language.Haskell.Brittany.Internal.Layouters.Decl
( layoutDecl
, layoutSig
, layoutBind
, layoutLocalBinds
, layoutGuardLStmt
, layoutPatternBind
, layoutGrhs
, layoutPatternBindFinal
)
where
#include "prelude.inc"
import Language.Haskell.Brittany.Internal.Types
import Language.Haskell.Brittany.Internal.LayouterBasics
import Language.Haskell.Brittany.Internal.Config.Types
import qualified Language.Haskell.GHC.ExactPrint as ExactPrint
import qualified Language.Haskell.GHC.ExactPrint.Types as ExactPrint
import Language.Haskell.Brittany.Internal.ExactPrintUtils
import Language.Haskell.Brittany.Internal.Utils
import GHC ( runGhc
, GenLocated(L)
, moduleNameString
, AnnKeywordId (..)
)
import SrcLoc ( SrcSpan, noSrcSpan, Located , getLoc, unLoc )
import HsSyn
import Name
import BasicTypes ( InlinePragma(..)
, Activation(..)
, InlineSpec(..)
, RuleMatchInfo(..)
#if MIN_VERSION_ghc(8,2,0)
, LexicalFixity(..)
#endif
)
import Language.Haskell.GHC.ExactPrint.Types ( mkAnnKey )
import Language.Haskell.Brittany.Internal.Layouters.Type
import {-# SOURCE #-} Language.Haskell.Brittany.Internal.Layouters.Expr
import {-# SOURCE #-} Language.Haskell.Brittany.Internal.Layouters.Stmt
import Language.Haskell.Brittany.Internal.Layouters.Pattern
import Bag ( mapBagM, bagToList, emptyBag )
import Data.Char (isUpper)
layoutDecl :: ToBriDoc HsDecl
layoutDecl d@(L loc decl) = case decl of
SigD sig -> withTransformedAnns d $ layoutSig (L loc sig)
ValD bind -> withTransformedAnns d $ layoutBind (L loc bind) >>= \case
Left ns -> docLines $ return <$> ns
Right n -> return n
TyClD tycl -> withTransformedAnns d $ layoutTyCl (L loc tycl)
InstD (TyFamInstD{}) -> do
-- this is a (temporary (..)) workaround for "type instance" decls
-- that do not round-trip through exactprint properly.
let fixer s = case List.stripPrefix "type " s of
Just rest | not ("instance" `isPrefixOf` rest) ->
"type instance " ++ rest
_ -> s
str <- mAsk <&> \anns ->
intercalate "\n" $ fmap fixer $ lines' $ ExactPrint.exactPrint d anns
allocateNode $ BDFExternal (ExactPrint.mkAnnKey d)
(foldedAnnKeys d)
False
(Text.pack str)
InstD (ClsInstD inst) -> withTransformedAnns d $ layoutClsInst (L loc inst)
_ -> briDocByExactNoComment d
--------------------------------------------------------------------------------
-- Sig
--------------------------------------------------------------------------------
layoutSig :: ToBriDoc Sig
layoutSig lsig@(L _loc sig) = case sig of
#if MIN_VERSION_ghc(8,2,0) /* ghc-8.2 */
TypeSig names (HsWC _ (HsIB _ typ _)) -> layoutNamesAndType names typ
#else /* ghc-8.0 */
TypeSig names (HsIB _ (HsWC _ _ typ)) -> layoutNamesAndType names typ
#endif
InlineSig name (InlinePragma _ spec _arity phaseAct conlike) ->
docWrapNode lsig $ do
nameStr <- lrdrNameToTextAnn name
specStr <- specStringCompat lsig spec
let phaseStr = case phaseAct of
NeverActive -> "" -- not [] - for NOINLINE NeverActive is
-- in fact the default
AlwaysActive -> ""
ActiveBefore _ i -> "[~" ++ show i ++ "] "
ActiveAfter _ i -> "[" ++ show i ++ "] "
let conlikeStr = case conlike of
FunLike -> ""
ConLike -> "CONLIKE "
docLit
$ Text.pack ("{-# " ++ specStr ++ conlikeStr ++ phaseStr)
<> nameStr
<> Text.pack " #-}"
#if MIN_VERSION_ghc(8,2,0) /* ghc-8.2 */
ClassOpSig False names (HsIB _ typ _) -> layoutNamesAndType names typ
#else /* ghc-8.0 */
ClassOpSig False names (HsIB _ typ) -> layoutNamesAndType names typ
#endif
_ -> briDocByExactNoComment lsig -- TODO
where
layoutNamesAndType names typ = docWrapNode lsig $ do
nameStrs <- names `forM` lrdrNameToTextAnn
let nameStr = Text.intercalate (Text.pack ", ") $ nameStrs
typeDoc <- docSharedWrapper layoutType typ
hasComments <- hasAnyCommentsBelow lsig
shouldBeHanging <- mAsk
<&> _conf_layout
.> _lconfig_hangingTypeSignature
.> confUnpack
if shouldBeHanging
then docSeq
[ appSep $ docWrapNodeRest lsig $ docLit nameStr
, docSetBaseY $ docLines
[ docCols
ColTyOpPrefix
[ docLit $ Text.pack ":: "
, docAddBaseY (BrIndentSpecial 3) $ typeDoc
]
]
]
else
docAlt
$ [ docSeq
[ appSep $ docWrapNodeRest lsig $ docLit nameStr
, appSep $ docLit $ Text.pack "::"
, docForceSingleline typeDoc
]
| not hasComments
]
++ [ docAddBaseY BrIndentRegular $ docPar
(docWrapNodeRest lsig $ docLit nameStr)
( docCols
ColTyOpPrefix
[ docLit $ Text.pack ":: "
, docAddBaseY (BrIndentSpecial 3) $ typeDoc
]
)
]
specStringCompat
:: MonadMultiWriter [BrittanyError] m => LSig GhcPs -> InlineSpec -> m String
#if MIN_VERSION_ghc(8,4,0)
specStringCompat ast = \case
NoUserInline -> mTell [ErrorUnknownNode "NoUserInline" ast] $> ""
Inline -> pure "INLINE "
Inlinable -> pure "INLINABLE "
NoInline -> pure "NOINLINE "
#else
specStringCompat _ = \case
Inline -> pure "INLINE "
Inlinable -> pure "INLINABLE "
NoInline -> pure "NOINLINE "
EmptyInlineSpec -> pure ""
#endif
layoutGuardLStmt :: ToBriDoc' (Stmt GhcPs (LHsExpr GhcPs))
layoutGuardLStmt lgstmt@(L _ stmtLR) = docWrapNode lgstmt $ case stmtLR of
BodyStmt body _ _ _ -> layoutExpr body
BindStmt lPat expr _ _ _ -> do
patDoc <- docSharedWrapper layoutPat lPat
expDoc <- docSharedWrapper layoutExpr expr
docCols ColBindStmt
[ appSep $ colsWrapPat =<< patDoc
, docSeq [appSep $ docLit $ Text.pack "<-", expDoc]
]
_ -> unknownNodeError "" lgstmt -- TODO
--------------------------------------------------------------------------------
-- HsBind
--------------------------------------------------------------------------------
layoutBind
:: ToBriDocC
(HsBindLR GhcPs GhcPs)
(Either [BriDocNumbered] BriDocNumbered)
layoutBind lbind@(L _ bind) = case bind of
FunBind fId (MG lmatches@(L _ matches) _ _ _) _ _ [] -> do
idStr <- lrdrNameToTextAnn fId
binderDoc <- docLit $ Text.pack "="
funcPatDocs <-
docWrapNode lbind
$ docWrapNode lmatches
$ layoutPatternBind (Just idStr) binderDoc
`mapM` matches
return $ Left $ funcPatDocs
PatBind pat (GRHSs grhss whereBinds) _ _ ([], []) -> do
patDocs <- colsWrapPat =<< layoutPat pat
clauseDocs <- layoutGrhs `mapM` grhss
mWhereDocs <- layoutLocalBinds whereBinds
binderDoc <- docLit $ Text.pack "="
hasComments <- hasAnyCommentsBelow lbind
fmap Right $ docWrapNode lbind $ layoutPatternBindFinal Nothing
binderDoc
(Just patDocs)
clauseDocs
mWhereDocs
hasComments
_ -> Right <$> unknownNodeError "" lbind
data BagBindOrSig = BagBind (LHsBindLR GhcPs GhcPs)
| BagSig (LSig GhcPs)
bindOrSigtoSrcSpan :: BagBindOrSig -> SrcSpan
bindOrSigtoSrcSpan (BagBind (L l _)) = l
bindOrSigtoSrcSpan (BagSig (L l _)) = l
layoutLocalBinds
:: ToBriDocC (HsLocalBindsLR GhcPs GhcPs) (Maybe [BriDocNumbered])
layoutLocalBinds lbinds@(L _ binds) = case binds of
-- HsValBinds (ValBindsIn lhsBindsLR []) ->
-- Just . (>>= either id return) . Data.Foldable.toList <$> mapBagM layoutBind lhsBindsLR -- TODO: fix ordering
-- x@(HsValBinds (ValBindsIn{})) ->
-- Just . (:[]) <$> unknownNodeError "HsValBinds (ValBindsIn _ (_:_))" x
HsValBinds (ValBindsIn bindlrs sigs) -> do
let unordered =
[ BagBind b | b <- Data.Foldable.toList bindlrs ]
++ [ BagSig s | s <- sigs ]
ordered = sortBy (comparing bindOrSigtoSrcSpan) unordered
docs <- docWrapNode lbinds $ join <$> ordered `forM` \case
BagBind b -> either id return <$> layoutBind b
BagSig s -> return <$> layoutSig s
return $ Just $ docs
x@(HsValBinds (ValBindsOut _binds _lsigs)) ->
-- i _think_ this case never occurs in non-processed ast
Just . (: []) <$> unknownNodeError "HsValBinds ValBindsOut{}"
(L noSrcSpan x)
x@(HsIPBinds _ipBinds) ->
Just . (: []) <$> unknownNodeError "HsIPBinds" (L noSrcSpan x)
EmptyLocalBinds -> return $ Nothing
-- TODO: we don't need the `LHsExpr GhcPs` anymore, now that there is
-- parSpacing stuff.B
layoutGrhs
:: LGRHS GhcPs (LHsExpr GhcPs)
-> ToBriDocM ([BriDocNumbered], BriDocNumbered, LHsExpr GhcPs)
layoutGrhs lgrhs@(L _ (GRHS guards body)) = do
guardDocs <- docWrapNode lgrhs $ layoutStmt `mapM` guards
bodyDoc <- layoutExpr body
return (guardDocs, bodyDoc, body)
layoutPatternBind
:: Maybe Text
-> BriDocNumbered
-> LMatch GhcPs (LHsExpr GhcPs)
-> ToBriDocM BriDocNumbered
layoutPatternBind mIdStr binderDoc lmatch@(L _ match) = do
let pats = m_pats match
let (GRHSs grhss whereBinds) = m_grhss match
patDocs <- pats `forM` \p -> fmap return $ colsWrapPat =<< layoutPat p
let isInfix = isInfixMatch match
let mIdStr' = fixPatternBindIdentifier match <$> mIdStr
patDoc <- docWrapNodePrior lmatch $ case (mIdStr', patDocs) of
(Just idStr, p1 : pr) | isInfix -> docCols
ColPatternsFuncInfix
( [appSep $ docForceSingleline p1, appSep $ docLit idStr]
++ (spacifyDocs $ docForceSingleline <$> pr)
)
(Just idStr, []) -> docLit idStr
(Just idStr, ps) ->
docCols ColPatternsFuncPrefix
$ appSep (docLit $ idStr)
: (spacifyDocs $ docForceSingleline <$> ps)
(Nothing, ps) ->
docCols ColPatterns
$ (List.intersperse docSeparator $ docForceSingleline <$> ps)
clauseDocs <- docWrapNodeRest lmatch $ layoutGrhs `mapM` grhss
mWhereDocs <- layoutLocalBinds whereBinds
let alignmentToken = if null pats then Nothing else mIdStr
hasComments <- hasAnyCommentsBelow lmatch
layoutPatternBindFinal alignmentToken
binderDoc
(Just patDoc)
clauseDocs
mWhereDocs
hasComments
#if MIN_VERSION_ghc(8,2,0) /* ghc-8.2 && ghc-8.4 */
fixPatternBindIdentifier
:: Match GhcPs (LHsExpr GhcPs) -> Text -> Text
fixPatternBindIdentifier match idStr = go $ m_ctxt match
where
go = \case
(FunRhs _ _ SrcLazy ) -> Text.cons '~' idStr
(FunRhs _ _ SrcStrict ) -> Text.cons '!' idStr
(FunRhs _ _ NoSrcStrict) -> idStr
(StmtCtxt ctx1 ) -> goInner ctx1
_ -> idStr
-- I have really no idea if this path ever occurs, but better safe than
-- risking another "drop bangpatterns" bugs.
goInner = \case
(PatGuard ctx1) -> go ctx1
(ParStmtCtxt ctx1) -> goInner ctx1
(TransStmtCtxt ctx1) -> goInner ctx1
_ -> idStr
#else /* ghc-8.0 */
fixPatternBindIdentifier :: Match GhcPs (LHsExpr GhcPs) -> Text -> Text
fixPatternBindIdentifier _ x = x
#endif
layoutPatternBindFinal
:: Maybe Text
-> BriDocNumbered
-> Maybe BriDocNumbered
-> [([BriDocNumbered], BriDocNumbered, LHsExpr GhcPs)]
-> Maybe [BriDocNumbered]
-> Bool
-> ToBriDocM BriDocNumbered
layoutPatternBindFinal alignmentToken binderDoc mPatDoc clauseDocs mWhereDocs hasComments = do
let patPartInline = case mPatDoc of
Nothing -> []
Just patDoc -> [appSep $ docForceSingleline $ return patDoc]
patPartParWrap = case mPatDoc of
Nothing -> id
Just patDoc -> docPar (return patDoc)
whereIndent <- do
shouldSpecial <- mAsk
<&> _conf_layout
.> _lconfig_indentWhereSpecial
.> confUnpack
regularIndentAmount <- mAsk
<&> _conf_layout
.> _lconfig_indentAmount
.> confUnpack
pure $ if shouldSpecial
then BrIndentSpecial (max 1 (regularIndentAmount `div` 2))
else BrIndentRegular
-- TODO: apart from this, there probably are more nodes below which could
-- be shared between alternatives.
wherePartMultiLine :: [ToBriDocM BriDocNumbered] <- case mWhereDocs of
Nothing -> return $ []
Just [w] -> fmap (pure . pure) $ docAlt
[ docEnsureIndent BrIndentRegular
$ docSeq
[ docLit $ Text.pack "where"
, docSeparator
, docForceSingleline $ return w
]
, docEnsureIndent whereIndent $ docLines
[ docLit $ Text.pack "where"
, docEnsureIndent whereIndent
$ docSetIndentLevel
$ docNonBottomSpacing
$ return w
]
]
Just ws -> fmap (pure . pure) $ docEnsureIndent whereIndent $ docLines
[ docLit $ Text.pack "where"
, docEnsureIndent whereIndent
$ docSetIndentLevel
$ docNonBottomSpacing
$ docLines
$ return
<$> ws
]
let singleLineGuardsDoc guards = appSep $ case guards of
[] -> docEmpty
[g] -> docSeq
[appSep $ docLit $ Text.pack "|", docForceSingleline $ return g]
gs -> docSeq
$ [appSep $ docLit $ Text.pack "|"]
++ (List.intersperse docCommaSep
(docForceSingleline . return <$> gs)
)
wherePart = case mWhereDocs of
Nothing -> Just docEmpty
Just [w] -> Just $ docSeq
[ docSeparator
, appSep $ docLit $ Text.pack "where"
, docSetIndentLevel $ docForceSingleline $ return w
]
_ -> Nothing
indentPolicy <- mAsk
<&> _conf_layout
.> _lconfig_indentPolicy
.> confUnpack
runFilteredAlternative $ do
case clauseDocs of
[(guards, body, _bodyRaw)] -> do
let guardPart = singleLineGuardsDoc guards
forM_ wherePart $ \wherePart' ->
-- one-line solution
addAlternativeCond (not hasComments) $ docCols
(ColBindingLine alignmentToken)
[ docSeq (patPartInline ++ [guardPart])
, docSeq
[ appSep $ return binderDoc
, docForceSingleline $ return body
, wherePart'
]
]
-- one-line solution + where in next line(s)
addAlternativeCond (Data.Maybe.isJust mWhereDocs)
$ docLines
$ [ docCols
(ColBindingLine alignmentToken)
[ docSeq (patPartInline ++ [guardPart])
, docSeq
[appSep $ return binderDoc, docForceParSpacing $ return body]
]
]
++ wherePartMultiLine
-- two-line solution + where in next line(s)
addAlternative
$ docLines
$ [ docForceSingleline
$ docSeq (patPartInline ++ [guardPart, return binderDoc])
, docEnsureIndent BrIndentRegular $ docForceSingleline $ return body
]
++ wherePartMultiLine
-- pattern and exactly one clause in single line, body as par;
-- where in following lines
addAlternative
$ docLines
$ [ docCols
(ColBindingLine alignmentToken)
[ docSeq (patPartInline ++ [guardPart])
, docSeq
[ appSep $ return binderDoc
, docForceParSpacing $ docAddBaseY BrIndentRegular $ return body
]
]
]
-- , lineMod $ docAlt
-- [ docSetBaseY $ return body
-- , docAddBaseY BrIndentRegular $ return body
-- ]
++ wherePartMultiLine
-- pattern and exactly one clause in single line, body in new line.
addAlternative
$ docLines
$ [ docSeq (patPartInline ++ [guardPart, return binderDoc])
, docNonBottomSpacing
$ docEnsureIndent BrIndentRegular
$ docAddBaseY BrIndentRegular
$ return body
]
++ wherePartMultiLine
_ -> return () -- no alternatives exclusively when `length clauseDocs /= 1`
case mPatDoc of
Nothing -> return ()
Just patDoc ->
-- multiple clauses added in-paragraph, each in a single line
-- example: foo | bar = baz
-- | lll = asd
addAlternativeCond (indentPolicy == IndentPolicyFree)
$ docLines
$ [ docSeq
[ appSep $ docForceSingleline $ return patDoc
, docSetBaseY
$ docLines
$ clauseDocs
<&> \(guardDocs, bodyDoc, _) -> do
let guardPart = singleLineGuardsDoc guardDocs
-- the docForceSingleline might seems superflous, but it
-- helps the alternative resolving impl.
docForceSingleline $ docCols
ColGuardedBody
[ guardPart
, docSeq
[ appSep $ return binderDoc
, docForceSingleline $ return bodyDoc
-- i am not sure if there is a benefit to using
-- docForceParSpacing additionally here:
-- , docAddBaseY BrIndentRegular $ return bodyDoc
]
]
]
]
++ wherePartMultiLine
-- multiple clauses, each in a separate, single line
addAlternative
$ docLines
$ [ docAddBaseY BrIndentRegular
$ patPartParWrap
$ docLines
$ map docSetBaseY
$ clauseDocs
<&> \(guardDocs, bodyDoc, _) -> do
let guardPart = singleLineGuardsDoc guardDocs
-- the docForceSingleline might seems superflous, but it
-- helps the alternative resolving impl.
docForceSingleline $ docCols
ColGuardedBody
[ guardPart
, docSeq
[ appSep $ return binderDoc
, docForceSingleline $ return bodyDoc
-- i am not sure if there is a benefit to using
-- docForceParSpacing additionally here:
-- , docAddBaseY BrIndentRegular $ return bodyDoc
]
]
]
++ wherePartMultiLine
-- multiple clauses, each with the guard(s) in a single line, body
-- as a paragraph
addAlternative
$ docLines
$ [ docAddBaseY BrIndentRegular
$ patPartParWrap
$ docLines
$ map docSetBaseY
$ clauseDocs
<&> \(guardDocs, bodyDoc, _) ->
docSeq
$ ( case guardDocs of
[] -> []
[g] ->
[ docForceSingleline
$ docSeq [appSep $ docLit $ Text.pack "|", return g]
]
gs ->
[ docForceSingleline
$ docSeq
$ [appSep $ docLit $ Text.pack "|"]
++ List.intersperse docCommaSep (return <$> gs)
]
)
++ [ docSeparator
, docCols
ColOpPrefix
[ appSep $ return binderDoc
, docAddBaseY BrIndentRegular
$ docForceParSpacing
$ return bodyDoc
]
]
]
++ wherePartMultiLine
-- multiple clauses, each with the guard(s) in a single line, body
-- in a new line as a paragraph
addAlternative
$ docLines
$ [ docAddBaseY BrIndentRegular
$ patPartParWrap
$ docLines
$ map docSetBaseY
$ clauseDocs
>>= \(guardDocs, bodyDoc, _) ->
( case guardDocs of
[] -> []
[g] ->
[ docForceSingleline
$ docSeq [appSep $ docLit $ Text.pack "|", return g]
]
gs ->
[ docForceSingleline
$ docSeq
$ [appSep $ docLit $ Text.pack "|"]
++ List.intersperse docCommaSep (return <$> gs)
]
)
++ [ docCols
ColOpPrefix
[ appSep $ return binderDoc
, docAddBaseY BrIndentRegular
$ docForceParSpacing
$ return bodyDoc
]
]
]
++ wherePartMultiLine
-- conservative approach: everything starts on the left.
addAlternative
$ docLines
$ [ docAddBaseY BrIndentRegular
$ patPartParWrap
$ docLines
$ map docSetBaseY
$ clauseDocs
>>= \(guardDocs, bodyDoc, _) ->
( case guardDocs of
[] -> []
[g] ->
[docSeq [appSep $ docLit $ Text.pack "|", return g]]
(g1:gr) ->
( docSeq [appSep $ docLit $ Text.pack "|", return g1]
: ( gr
<&> \g ->
docSeq
[appSep $ docLit $ Text.pack ",", return g]
)
)
)
++ [ docCols
ColOpPrefix
[ appSep $ return binderDoc
, docAddBaseY BrIndentRegular $ return bodyDoc
]
]
]
++ wherePartMultiLine
--------------------------------------------------------------------------------
-- TyClDecl
--------------------------------------------------------------------------------
layoutTyCl :: ToBriDoc TyClDecl
layoutTyCl ltycl@(L _loc tycl) = case tycl of
#if MIN_VERSION_ghc(8,2,0)
SynDecl name vars fixity typ _ -> do
let isInfix = case fixity of
Prefix -> False
Infix -> True
#else
SynDecl name vars typ _ -> do
nameStr <- lrdrNameToTextAnn name
let isInfixTypeOp = case Text.uncons nameStr of
Nothing -> False
Just (c, _) -> not (c == '(' || isUpper c)
isInfix <- (isInfixTypeOp ||) <$> hasAnnKeyword name AnnBackquote
#endif
-- hasTrailingParen <- hasAnnKeywordComment ltycl AnnCloseP
-- let parenWrapper = if hasTrailingParen
-- then appSep . docWrapNodeRest ltycl
-- else id
let wrapNodeRest = docWrapNodeRest ltycl
docWrapNodePrior ltycl
$ layoutSynDecl isInfix wrapNodeRest name (hsq_explicit vars) typ
_ -> briDocByExactNoComment ltycl
layoutSynDecl
:: Bool
-> (ToBriDocM BriDocNumbered -> ToBriDocM BriDocNumbered)
-> Located (IdP GhcPs)
-> [LHsTyVarBndr GhcPs]
-> LHsType GhcPs
-> ToBriDocM BriDocNumbered
layoutSynDecl isInfix wrapNodeRest name vars typ = do
nameStr <- lrdrNameToTextAnn name
let
lhs = appSep . wrapNodeRest $ if isInfix
then do
let (a : b : rest) = vars
hasOwnParens <- hasAnnKeywordComment a AnnOpenP
-- This isn't quite right, but does give syntactically valid results
let needsParens = not $ null rest || hasOwnParens
docSeq
$ [ docLit $ Text.pack "type"
, docSeparator
]
++ [ docParenL | needsParens ]
++ [ layoutTyVarBndr False a
, docSeparator
, docLit nameStr
, docSeparator
, layoutTyVarBndr False b
]
++ [ docParenR | needsParens ]
++ fmap (layoutTyVarBndr True) rest
else
docSeq
$ [ docLit $ Text.pack "type"
, docSeparator
, docWrapNode name $ docLit nameStr
]
++ fmap (layoutTyVarBndr True) vars
sharedLhs <- docSharedWrapper id lhs
typeDoc <- docSharedWrapper layoutType typ
hasComments <- hasAnyCommentsConnected typ
runFilteredAlternative $ do
addAlternativeCond (not hasComments) $ docSeq
[sharedLhs, appSep $ docLit $ Text.pack "=", docForceSingleline typeDoc]
addAlternative $ docAddBaseY BrIndentRegular $ docPar
sharedLhs
(docCols ColTyOpPrefix [appSep $ docLit $ Text.pack "=", typeDoc])
layoutTyVarBndr :: Bool -> ToBriDoc HsTyVarBndr
layoutTyVarBndr needsSep lbndr@(L _ bndr) = do
docWrapNodePrior lbndr $ case bndr of
UserTyVar name -> do
nameStr <- lrdrNameToTextAnn name
docSeq $ [docSeparator | needsSep] ++ [docLit nameStr]
KindedTyVar name kind -> do
nameStr <- lrdrNameToTextAnn name
docSeq
$ [ docSeparator | needsSep ]
++ [ docLit $ Text.pack "("
, appSep $ docLit nameStr
, appSep . docLit $ Text.pack "::"
, docForceSingleline $ layoutType kind
, docLit $ Text.pack ")"
]
--------------------------------------------------------------------------------
-- ClsInstDecl
--------------------------------------------------------------------------------
-- | Layout an @instance@ declaration
--
-- Layout signatures and bindings using the corresponding layouters from the
-- top-level. Layout the instance head, type family instances, and data family
-- instances using ExactPrint.
layoutClsInst :: ToBriDoc ClsInstDecl
layoutClsInst lcid@(L _ cid) = docLines
[ layoutInstanceHead
, docEnsureIndent BrIndentRegular
$ docSortedLines
$ fmap layoutAndLocateSig (cid_sigs cid)
++ fmap layoutAndLocateBind (bagToList $ cid_binds cid)
++ fmap layoutAndLocateTyFamInsts (cid_tyfam_insts cid)
++ fmap layoutAndLocateDataFamInsts (cid_datafam_insts cid)
]
where
layoutInstanceHead :: ToBriDocM BriDocNumbered
layoutInstanceHead =
briDocByExactNoComment $ InstD . ClsInstD . removeChildren <$> lcid
removeChildren :: ClsInstDecl p -> ClsInstDecl p
removeChildren c = c
{ cid_binds = emptyBag
, cid_sigs = []
, cid_tyfam_insts = []
, cid_datafam_insts = []
}
-- | Like 'docLines', but sorts the lines based on location
docSortedLines
:: [ToBriDocM (Located BriDocNumbered)] -> ToBriDocM BriDocNumbered
docSortedLines l =
allocateNode . BDFLines . fmap unLoc . List.sortOn getLoc =<< sequence l
layoutAndLocateSig :: ToBriDocC (Sig GhcPs) (Located BriDocNumbered)
layoutAndLocateSig lsig@(L loc _) = L loc <$> layoutSig lsig
layoutAndLocateBind :: ToBriDocC (HsBind GhcPs) (Located BriDocNumbered)
layoutAndLocateBind lbind@(L loc _) =
L loc <$> (joinBinds =<< layoutBind lbind)
joinBinds
:: Either [BriDocNumbered] BriDocNumbered -> ToBriDocM BriDocNumbered
joinBinds = \case
Left ns -> docLines $ return <$> ns
Right n -> return n
layoutAndLocateTyFamInsts
:: ToBriDocC (TyFamInstDecl GhcPs) (Located BriDocNumbered)
layoutAndLocateTyFamInsts ltfid@(L loc _) =
L loc <$> layoutTyFamInstDecl ltfid
-- | Send to ExactPrint then remove unecessary whitespace
layoutTyFamInstDecl :: ToBriDoc TyFamInstDecl
layoutTyFamInstDecl ltfid =
fmap stripWhitespace <$> briDocByExactNoComment ltfid
layoutAndLocateDataFamInsts
:: ToBriDocC (DataFamInstDecl GhcPs) (Located BriDocNumbered)
layoutAndLocateDataFamInsts ldfid@(L loc _) =
L loc <$> layoutDataFamInstDecl ldfid
-- | Send to ExactPrint then remove unecessary whitespace
layoutDataFamInstDecl :: ToBriDoc DataFamInstDecl
layoutDataFamInstDecl ldfid =
fmap stripWhitespace <$> briDocByExactNoComment ldfid
-- | ExactPrint adds indentation/newlines to @data@/@type@ declarations
stripWhitespace :: BriDocF f -> BriDocF f
stripWhitespace (BDFExternal ann anns b t) =
BDFExternal ann anns b $ stripWhitespace' t
stripWhitespace b = b
-- | This fixes two issues of output coming from Exactprinting
-- associated (data) type decls. Firstly we place the output into docLines,
-- so one newline coming from Exactprint is superfluous, so we drop the
-- first (empty) line. The second issue is Exactprint indents the first
-- member in a strange fashion:
--
-- input:
--
-- > instance MyClass Int where
-- > -- | This data is very important
-- > data MyData = IntData
-- > { intData :: String
-- > , intData2 :: Int
-- > }
--
-- output of just exactprinting the associated data type syntax node
--
-- >
-- > -- | This data is very important
-- > data MyData = IntData
-- > { intData :: String
-- > , intData2 :: Int
-- > }
--
-- To fix this, we strip whitespace from the start of the comments and the
-- first line of the declaration, stopping when we see "data" or "type" at
-- the start of a line. I.e., this function yields
--
-- > -- | This data is very important
-- > data MyData = IntData
-- > { intData :: String
-- > , intData2 :: Int
-- > }
--
-- Downside apart from being a hacky and brittle fix is that this removes
-- possible additional indentation from comments before the first member.
--
-- But the whole thing is just a temporary measure until brittany learns
-- to layout data/type decls.
stripWhitespace' :: Text -> Text
stripWhitespace' t =
Text.intercalate (Text.pack "\n") $ go $ List.drop 1 $ Text.lines t
where
go [] = []
go (line1 : lineR) = case Text.stripStart line1 of
st | isTypeOrData st -> st : lineR
| otherwise -> st : go lineR
isTypeOrData t' =
(Text.pack "type" `Text.isPrefixOf` t')
|| (Text.pack "data" `Text.isPrefixOf` t')
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