module Language.Haskell.Stylish.Step.Squash
( step
) where
import Data.Maybe (mapMaybe)
import qualified Language.Haskell.Exts as H
import Language.Haskell.Stylish.Editor
import Language.Haskell.Stylish.Step
import Language.Haskell.Stylish.Util
squash
:: (H.Annotated l, H.Annotated r)
=> l H.SrcSpan -> r H.SrcSpan -> Maybe (Change String)
squash left right
| H.srcSpanEndLine lAnn == H.srcSpanStartLine rAnn = Just $
changeLine (H.srcSpanEndLine lAnn) $ \str ->
let (pre, post) = splitAt (H.srcSpanEndColumn lAnn) str
in [trimRight pre ++ " " ++ trimLeft post]
| otherwise = Nothing
where
lAnn = H.ann left
rAnn = H.ann right
squashFieldDecl :: H.FieldDecl H.SrcSpan -> Maybe (Change String)
squashFieldDecl (H.FieldDecl _ names type')
| null names = Nothing
| otherwise = squash (last names) type'
squashMatch :: H.Match H.SrcSpan -> Maybe (Change String)
squashMatch (H.InfixMatch _ _ _ _ _ _) = Nothing
squashMatch (H.Match _ name pats rhs _)
| null pats = squash name rhs
| otherwise = squash (last pats) rhs
squashAlt :: H.Alt H.SrcSpan -> Maybe (Change String)
squashAlt (H.Alt _ pat rhs _) = squash pat rhs
step :: Step
step = makeStep "Squash" $ \ls (module', _) ->
let module'' = fmap H.srcInfoSpan module'
changes = concat
[ mapMaybe squashAlt (everything module'')
, mapMaybe squashMatch (everything module'')
, mapMaybe squashFieldDecl (everything module'')
]
in applyChanges changes ls