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--------------------------------------------------------------------------------
{-# LANGUAGE TypeFamilies #-}
module Language.Haskell.Stylish.Step.SimpleAlign
( Config (..)
, defaultConfig
, step
) where
--------------------------------------------------------------------------------
import Control.Monad (guard)
import Data.List (foldl')
import Data.Maybe (fromMaybe)
import qualified GHC.Hs as Hs
import qualified SrcLoc as S
--------------------------------------------------------------------------------
import Language.Haskell.Stylish.Align
import Language.Haskell.Stylish.Editor
import Language.Haskell.Stylish.Module
import Language.Haskell.Stylish.Step
import Language.Haskell.Stylish.Util
--------------------------------------------------------------------------------
data Config = Config
{ cCases :: !Bool
, cTopLevelPatterns :: !Bool
, cRecords :: !Bool
} deriving (Show)
--------------------------------------------------------------------------------
defaultConfig :: Config
defaultConfig = Config
{ cCases = True
, cTopLevelPatterns = True
, cRecords = True
}
--------------------------------------------------------------------------------
type Record = [S.Located (Hs.ConDeclField Hs.GhcPs)]
--------------------------------------------------------------------------------
records :: S.Located (Hs.HsModule Hs.GhcPs) -> [Record]
records modu = do
let decls = map S.unLoc (Hs.hsmodDecls (S.unLoc modu))
tyClDecls = [ tyClDecl | Hs.TyClD _ tyClDecl <- decls ]
dataDecls = [ d | d@(Hs.DataDecl _ _ _ _ _) <- tyClDecls ]
dataDefns = map Hs.tcdDataDefn dataDecls
d@Hs.ConDeclH98 {} <- concatMap getConDecls dataDefns
case Hs.con_args d of
Hs.RecCon rec -> [S.unLoc rec]
_ -> []
where
getConDecls :: Hs.HsDataDefn Hs.GhcPs -> [Hs.ConDecl Hs.GhcPs]
getConDecls d@Hs.HsDataDefn {} = map S.unLoc $ Hs.dd_cons d
getConDecls (Hs.XHsDataDefn x) = Hs.noExtCon x
--------------------------------------------------------------------------------
recordToAlignable :: Record -> [Alignable S.RealSrcSpan]
recordToAlignable = fromMaybe [] . traverse fieldDeclToAlignable
--------------------------------------------------------------------------------
fieldDeclToAlignable
:: S.Located (Hs.ConDeclField Hs.GhcPs) -> Maybe (Alignable S.RealSrcSpan)
fieldDeclToAlignable (S.L _ (Hs.XConDeclField x)) = Hs.noExtCon x
fieldDeclToAlignable (S.L matchLoc (Hs.ConDeclField _ names ty _)) = do
matchPos <- toRealSrcSpan matchLoc
leftPos <- toRealSrcSpan $ S.getLoc $ last names
tyPos <- toRealSrcSpan $ S.getLoc ty
Just $ Alignable
{ aContainer = matchPos
, aLeft = leftPos
, aRight = tyPos
, aRightLead = length ":: "
}
--------------------------------------------------------------------------------
matchGroupToAlignable
:: Config
-> Hs.MatchGroup Hs.GhcPs (Hs.LHsExpr Hs.GhcPs)
-> [Alignable S.RealSrcSpan]
matchGroupToAlignable _conf (Hs.XMatchGroup x) = Hs.noExtCon x
matchGroupToAlignable conf (Hs.MG _ alts _) =
fromMaybe [] $ traverse (matchToAlignable conf) (S.unLoc alts)
--------------------------------------------------------------------------------
matchToAlignable
:: Config
-> S.Located (Hs.Match Hs.GhcPs (Hs.LHsExpr Hs.GhcPs))
-> Maybe (Alignable S.RealSrcSpan)
matchToAlignable conf (S.L matchLoc m@(Hs.Match _ Hs.CaseAlt pats@(_ : _) grhss)) = do
let patsLocs = map S.getLoc pats
pat = last patsLocs
guards = getGuards m
guardsLocs = map S.getLoc guards
left = foldl' S.combineSrcSpans pat guardsLocs
guard $ cCases conf
body <- rhsBody grhss
matchPos <- toRealSrcSpan matchLoc
leftPos <- toRealSrcSpan left
rightPos <- toRealSrcSpan $ S.getLoc body
Just $ Alignable
{ aContainer = matchPos
, aLeft = leftPos
, aRight = rightPos
, aRightLead = length "-> "
}
matchToAlignable conf (S.L matchLoc (Hs.Match _ (Hs.FunRhs name _ _) pats@(_ : _) grhss)) = do
guard $ cTopLevelPatterns conf
body <- unguardedRhsBody grhss
let patsLocs = map S.getLoc pats
nameLoc = S.getLoc name
left = last (nameLoc : patsLocs)
bodyLoc = S.getLoc body
matchPos <- toRealSrcSpan matchLoc
leftPos <- toRealSrcSpan left
bodyPos <- toRealSrcSpan bodyLoc
Just $ Alignable
{ aContainer = matchPos
, aLeft = leftPos
, aRight = bodyPos
, aRightLead = length "= "
}
matchToAlignable _conf (S.L _ (Hs.XMatch x)) = Hs.noExtCon x
matchToAlignable _conf (S.L _ (Hs.Match _ _ _ _)) = Nothing
--------------------------------------------------------------------------------
step :: Maybe Int -> Config -> Step
step maxColumns config = makeStep "Cases" $ \ls module' ->
let changes
:: (S.Located (Hs.HsModule Hs.GhcPs) -> [a])
-> (a -> [Alignable S.RealSrcSpan])
-> [Change String]
changes search toAlign = concat $
map (align maxColumns) . map toAlign $ search (parsedModule module')
configured :: [Change String]
configured = concat $
[changes records recordToAlignable | cRecords config] ++
[changes everything (matchGroupToAlignable config)] in
applyChanges configured ls
|
