Prepare implementation for `IndentPolicyLeft`

src/Language/Haskell/Brittany/Internal/Config/Types.hs

@@ -191,7 +191,7 @@ data IndentPolicy = IndentPolicyLeft -- never create a new indentation at more
                   | IndentPolicyFree -- can create new indentations whereever
                   | IndentPolicyMultiple -- can create indentations only
                                          -- at any n * amount.
-  deriving (Show, Generic, Data)
+  deriving (Eq, Show, Generic, Data)
 
 data AltChooser = AltChooserSimpleQuick -- always choose last alternative.
                                         -- leads to tons of sparsely filled

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

@@ -26,57 +26,58 @@ import {-# SOURCE #-} Language.Haskell.Brittany.Internal.Layouters.Expr
 
 
 layoutStmt :: ToBriDoc' (StmtLR RdrName RdrName (LHsExpr RdrName))
-layoutStmt lstmt@(L _ stmt) = docWrapNode lstmt $ case stmt of
-  LastStmt body False _    -> do
-    layoutExpr body
-  BindStmt lPat expr _ _ _ -> do
-    patDoc <- fmap return $ colsWrapPat =<< layoutPat lPat
-    expDoc <- docSharedWrapper layoutExpr expr
-    docAlt
-      [ docCols
-        ColBindStmt
-        [ appSep patDoc
-        , docSeq [appSep $ docLit $ Text.pack "<-", docForceParSpacing expDoc]
+layoutStmt lstmt@(L _ stmt) = do
+  docWrapNode lstmt $ case stmt of
+    LastStmt body False _ -> do
+      layoutExpr body
+    BindStmt lPat expr _ _ _ -> do
+      patDoc <- fmap return $ colsWrapPat =<< layoutPat lPat
+      expDoc <- docSharedWrapper layoutExpr expr
+      docAlt
+        [ docCols
+          ColBindStmt
+          [ appSep patDoc
+          , docSeq [appSep $ docLit $ Text.pack "<-", docForceParSpacing expDoc]
+          ]
+        , docCols
+          ColBindStmt
+          [ appSep patDoc
+          , docAddBaseY BrIndentRegular
+            $ docPar (docLit $ Text.pack "<-") (expDoc)
+          ]
         ]
-      , docCols
-        ColBindStmt
-        [ appSep patDoc
-        , docAddBaseY BrIndentRegular
-          $ docPar (docLit $ Text.pack "<-") (expDoc)
+    LetStmt binds -> layoutLocalBinds binds >>= \case
+      Nothing        -> docLit $ Text.pack "let" -- i just tested
+                                 -- it, and it is
+                                 -- indeed allowed.
+                                 -- heh.
+      Just []        -> docLit $ Text.pack "let" -- this probably never happens
+      Just [bindDoc] -> docAlt
+        [ docCols
+          ColDoLet
+          [ appSep $ docLit $ Text.pack "let"
+          , docSetBaseAndIndent $ return bindDoc
+          ]
+        , docAddBaseY BrIndentRegular $ docPar
+          (docLit $ Text.pack "let")
+          (docSetBaseAndIndent $ return bindDoc)
         ]
-      ]
-  LetStmt binds            -> layoutLocalBinds binds >>= \case
-    Nothing        -> docLit $ Text.pack "let" -- i just tested
-                               -- it, and it is
-                               -- indeed allowed.
-                               -- heh.
-    Just []        -> docLit $ Text.pack "let" -- this probably never happens
-    Just [bindDoc] -> docAlt
-      [ docCols
-        ColDoLet
-        [ appSep $ docLit $ Text.pack "let"
-        , docSetBaseAndIndent $ return bindDoc
+      Just bindDocs -> docAlt
+        [ docSeq
+          [ appSep $ docLit $ Text.pack "let"
+          , docSetBaseAndIndent $ docLines $ return <$> bindDocs
+          ]
+        , docAddBaseY BrIndentRegular $ docPar
+          (docLit $ Text.pack "let")
+          (docSetBaseAndIndent $ docLines $ return <$> bindDocs)
         ]
-      , docAddBaseY BrIndentRegular
-        $ docPar (docLit $ Text.pack "let")
-                 (docSetBaseAndIndent $ return bindDoc)
-      ]
-    Just bindDocs  -> docAlt
-      [ docSeq
-        [ appSep $ docLit $ Text.pack "let"
-        , docSetBaseAndIndent $ docLines $ return <$> bindDocs
+    RecStmt stmts _ _ _ _ _ _ _ _ _ -> do
+      docSeq
+        [ docLit (Text.pack "rec")
+        , docSeparator
+        , docSetBaseAndIndent $ docLines $ layoutStmt <$> stmts
         ]
-      , docAddBaseY BrIndentRegular $ docPar
-        (docLit $ Text.pack "let")
-        (docSetBaseAndIndent $ docLines $ return <$> bindDocs)
-      ]
-  RecStmt stmts _ _ _ _ _ _ _ _ _ -> do
-    docSeq
-      [ docLit (Text.pack "rec")
-      , docSeparator
-      , docSetBaseAndIndent $ docLines $ layoutStmt <$> stmts
-      ]
-  BodyStmt expr _ _ _      -> do
-    expDoc <- docSharedWrapper layoutExpr expr
-    docAddBaseY BrIndentRegular $ expDoc
-  _                        -> briDocByExactInlineOnly "some unknown statement" lstmt
+    BodyStmt expr _ _ _ -> do
+      expDoc <- docSharedWrapper layoutExpr expr
+      docAddBaseY BrIndentRegular $ expDoc
+    _ -> briDocByExactInlineOnly "some unknown statement" lstmt