Merge 62f2f4977d into e4dea87839

brittany.cabal

@@ -108,6 +108,7 @@ library {
     , cmdargs >=0.10.14 && <0.11
     , czipwith >=1.0.0.0 && <1.1
     , ghc-boot-th >=8.0.1 && <8.3
+    , text-latin1 >= 0.3 && < 0.4
     }
   default-extensions: {
     CPP

src/Language/Haskell/Brittany/Internal/Backend.hs

@@ -264,7 +264,7 @@ briDocLineLength briDoc = flip StateS.evalState False $ rec briDoc
  where
   rec = \case
     BDEmpty                 -> return $ 0
-    BDLit t                 -> StateS.put False $> Text.length t
+    BDLit t                 -> StateS.put False $> elasticLength t
     BDSeq bds               -> sum <$> rec `mapM` bds
     BDCols _ bds            -> sum <$> rec `mapM` bds
     BDSeparator -> StateS.get >>= \b -> StateS.put True $> if b then 0 else 1

src/Language/Haskell/Brittany/Internal/BackendUtils.hs

@@ -32,6 +32,7 @@ module Language.Haskell.Brittany.Internal.BackendUtils
   , layoutWritePriorComments
   , layoutWritePostComments
   , layoutRemoveIndentLevelLinger
+  , elasticLength
   )
 where
 
@@ -51,6 +52,7 @@ import           Language.Haskell.Brittany.Internal.Utils
 
 import           GHC ( Located, GenLocated(L), moduleNameString )
 
+import Text.Ascii (isAscii)
 
 
 traceLocal
@@ -97,11 +99,21 @@ layoutWriteAppend t = do
   mTell $ Text.Builder.fromText $ t
   mModify $ \s -> s
     { _lstate_curYOrAddNewline = Left $ case _lstate_curYOrAddNewline s of
-        Left c -> c + Text.length t + spaces
+        Left c -> c + elasticLength t + spaces
         Right{} -> Text.length t + spaces
     , _lstate_addSepSpace = Nothing
     }
 
+-- |
+-- >>> elasticLength "あ"
+-- 2
+-- >>> elasticLength "abc"
+-- 3
+-- >>> elasticLength "aあa"
+-- 4
+elasticLength :: Text -> Int
+elasticLength = Text.foldl' (\len c -> if isAscii c then len + 1 else len + 2) 0
+
 layoutWriteAppendSpaces
   :: ( MonadMultiWriter Text.Builder.Builder m
      , MonadMultiState LayoutState m