Implement IndentPolicyMultiple

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

@@ -436,7 +436,7 @@ layoutPatternBindFinal alignmentToken binderDoc mPatDoc clauseDocs mWhereDocs ha
         -- multiple clauses added in-paragraph, each in a single line
         -- example: foo | bar = baz
         --              | lll = asd
-        addAlternativeCond (indentPolicy /= IndentPolicyLeft)
+        addAlternativeCond (indentPolicy == IndentPolicyFree)
           $ docLines
           $  [ docSeq
                [ appSep $ docForceSingleline $ return patDoc

src/Language/Haskell/Brittany/Internal/Layouters/Expr.hs

@@ -422,7 +422,8 @@ layoutExpr lexpr@(L _ expr) = do
       let maySpecialIndent =
             case indentPolicy of
               IndentPolicyLeft -> BrIndentRegular
-              _ -> BrIndentSpecial 3
+              IndentPolicyMultiple -> BrIndentRegular
+              IndentPolicyFree -> BrIndentSpecial 3
       -- TODO: some of the alternatives (especially last and last-but-one)
       -- overlap.
       runFilteredAlternative $ do
@@ -541,7 +542,10 @@ layoutExpr lexpr@(L _ expr) = do
       let
         ifIndentLeftElse :: a -> a -> a
         ifIndentLeftElse x y =
-          if indentPolicy == IndentPolicyLeft then x else y
+          case indentPolicy of
+            IndentPolicyLeft -> x
+            IndentPolicyMultiple -> x
+            IndentPolicyFree -> y
       -- this `docSetBaseAndIndent` might seem out of place (especially the
       -- Indent part; setBase is necessary due to the use of docLines below),
       -- but is here due to ghc-exactprint's DP handling of "let" in
@@ -596,8 +600,7 @@ layoutExpr lexpr@(L _ expr) = do
           --    c = d
           --  in
           --    fooooooooooooooooooo
-          addAlternativeCond (indentPolicy == IndentPolicyLeft)
+          let noHangingBinds =
-            $ docLines
                 [ docAddBaseY BrIndentRegular
                 $ docPar
                   (docLit $ Text.pack "let")
@@ -607,7 +610,11 @@ layoutExpr lexpr@(L _ expr) = do
                   , docAddBaseY BrIndentRegular expDoc1
                   ]
                 ]
-          addAlternativeCond (indentPolicy /= IndentPolicyLeft)
+          addAlternativeCond (indentPolicy == IndentPolicyLeft)
+            $ docLines noHangingBinds
+          addAlternativeCond (indentPolicy == IndentPolicyMultiple)
+            $ docLines noHangingBinds
+          addAlternativeCond (indentPolicy == IndentPolicyFree)
             $ docLines
             [ docSeq
               [ appSep $ docLit $ Text.pack "let"
@@ -877,7 +884,7 @@ layoutExpr lexpr@(L _ expr) = do
         -- container { fieldA = blub
         --           , fieldB = blub
         --           }
-        addAlternativeCond (indentPolicy /= IndentPolicyLeft)
+        addAlternativeCond (indentPolicy == IndentPolicyFree)
           $ docSeq
           [ docNodeAnnKW lexpr Nothing $ appSep rExprDoc
           , docSetBaseY $ docLines $ let
@@ -918,9 +925,10 @@ layoutExpr lexpr@(L _ expr) = do
           $ docPar
               (docNodeAnnKW lexpr Nothing rExprDoc)
               (docNonBottomSpacing $ docLines $ let
-                expressionWrapper = if indentPolicy == IndentPolicyLeft
+                expressionWrapper = case indentPolicy of
-                  then docForceParSpacing
+                  IndentPolicyLeft -> docForceParSpacing
-                  else docSetBaseY
+                  IndentPolicyMultiple -> docForceParSpacing
+                  IndentPolicyFree -> docSetBaseY
                 line1 = docCols ColRecUpdate
                   [ appSep $ docLit $ Text.pack "{"
                   , docWrapNodePrior rF1f $ appSep $ docLit rF1n

src/Language/Haskell/Brittany/Internal/Layouters/Import.hs

@@ -48,7 +48,7 @@ layoutImport limportD@(L _ importD) = docWrapNode limportD $ case importD of
     importAsCol <- mAsk <&> _conf_layout .> _lconfig_importAsColumn .> confUnpack
     indentPolicy <- mAsk <&>  _conf_layout .> _lconfig_indentPolicy .> confUnpack
     let
-      compact  = indentPolicy == IndentPolicyLeft
+      compact  = indentPolicy /= IndentPolicyFree
       modNameT = Text.pack $ moduleNameString modName
       pkgNameT = Text.pack . prepPkg . sl_st <$> pkg
       masT     = Text.pack . moduleNameString . prepModName <$> mas

src/Language/Haskell/Brittany/Internal/Layouters/Stmt.hs

@@ -58,11 +58,11 @@ layoutStmt lstmt@(L _ stmt) = do
           docCols
           ColDoLet
           [ appSep $ docLit $ Text.pack "let"
-          , ( if indentPolicy == IndentPolicyLeft
+          , let f = case indentPolicy of
-              then docForceSingleline
+                  IndentPolicyFree     -> docSetBaseAndIndent
-              else docSetBaseAndIndent
+                  IndentPolicyLeft     -> docForceSingleline
-            )
+                  IndentPolicyMultiple -> docForceSingleline
-            $ return bindDoc
+            in  f $ return bindDoc
           ]
         , -- let
           --   bind = expr
@@ -74,8 +74,8 @@ layoutStmt lstmt@(L _ stmt) = do
         -- let aaa = expra
         --     bbb = exprb
         --     ccc = exprc
-        addAlternativeCond (indentPolicy /= IndentPolicyLeft)
+        -- TODO: Allow this for IndentPolicyMultiple when indentAmount = 4
-          $ docSeq
+        addAlternativeCond (indentPolicy == IndentPolicyFree) $ docSeq
           [ appSep $ docLit $ Text.pack "let"
           , docSetBaseAndIndent $ docLines $ return <$> bindDocs
           ]
@@ -83,16 +83,14 @@ layoutStmt lstmt@(L _ stmt) = do
         --   aaa = expra
         --   bbb = exprb
         --   ccc = exprc
-        addAlternative $
+        addAlternative $ docAddBaseY BrIndentRegular $ docPar
-          docAddBaseY BrIndentRegular $ docPar
           (docLit $ Text.pack "let")
           (docSetBaseAndIndent $ docLines $ return <$> bindDocs)
     RecStmt stmts _ _ _ _ _ _ _ _ _ -> runFilteredAlternative $ do
       -- rec stmt1
       --     stmt2
       --     stmt3
-      addAlternativeCond (indentPolicy /= IndentPolicyLeft)
+      addAlternativeCond (indentPolicy == IndentPolicyFree) $ docSeq
-        $ docSeq
         [ docLit (Text.pack "rec")
         , docSeparator
         , docSetBaseAndIndent $ docLines $ layoutStmt <$> stmts
@@ -101,9 +99,9 @@ layoutStmt lstmt@(L _ stmt) = do
       --   stmt1
       --   stmt2
       --   stmt3
-      addAlternative
+      addAlternative $ docAddBaseY BrIndentRegular $ docPar
-        $ docAddBaseY BrIndentRegular
+        (docLit (Text.pack "rec"))
-        $ docPar (docLit (Text.pack "rec")) (docLines $ layoutStmt <$> stmts)
+        (docLines $ layoutStmt <$> stmts)
     BodyStmt expr _ _ _ -> do
       expDoc <- docSharedWrapper layoutExpr expr
       docAddBaseY BrIndentRegular $ expDoc

src/Language/Haskell/Brittany/Internal/Transformations/Alt.hs

@@ -142,17 +142,23 @@ transformAlts =
         BDFAddBaseY indent bd -> do
           acp <- mGet
           indAmount <- mAsk <&> _conf_layout .> _lconfig_indentAmount .> confUnpack
+          indPolicy <- mAsk <&> _conf_layout .> _lconfig_indentPolicy .> confUnpack
           let indAdd = case indent of
                 BrIndentNone -> 0
                 BrIndentRegular -> indAmount
                 BrIndentSpecial i -> i
-          mSet $ acp { _acp_indentPrep = max (_acp_indentPrep acp) indAdd }
+          let indAdd' =
+                if indPolicy == IndentPolicyMultiple
+                then
+                  max 0 (indAdd - ((_acp_indent acp + indAdd) `mod` indAmount))
+                else indAdd
+          mSet $ acp { _acp_indentPrep = max (_acp_indentPrep acp) indAdd' }
           r <- rec bd
           acp' <- mGet
           mSet $ acp' { _acp_indent = _acp_indent acp }
           return $ case indent of
             BrIndentNone -> r
-            BrIndentRegular ->   reWrap $ BDFAddBaseY (BrIndentSpecial indAdd) r
+            BrIndentRegular ->   reWrap $ BDFAddBaseY (BrIndentSpecial indAdd') r
             BrIndentSpecial i -> reWrap $ BDFAddBaseY (BrIndentSpecial i) r
         BDFBaseYPushCur bd -> do
           acp <- mGet