cln: hlint: Clean up Maybe related hlint warnings.

.hlint.yaml

@@ -24,15 +24,12 @@
 - ignore: {name: "Use sortOn"}
 - ignore: {name: "Use camelCase"}
 - ignore: {name: "Use list comprehension"}
-- ignore: {name: "Use isNothing"}
 - ignore: {name: "Redundant <$>"}
 - ignore: {name: "Use list literal pattern"}
 - ignore: {name: "Use fewer imports"}
 - ignore: {name: "Use intercalate"}
 - ignore: {name: "Use tuple-section"}
 - ignore: {name: "Use section"}
-- ignore: {name: "Use maybe"}
-- ignore: {name: "Replace case with maybe"}
 - ignore: {name: "Avoid lambda using `infix`"}
 - ignore: {name: "Functor law"}
 - ignore: {name: "Missing NOINLINE pragma"}
@@ -42,7 +39,6 @@
 - ignore: {name: "Use void"}
 - ignore: {name: "Use elemIndex"}
 - ignore: {name: "Use lambda-case"}
-- ignore: {name: "Replace case with fromMaybe"}
 
 
 # Specify additional command line arguments

hledger-lib/Hledger/Data/Posting.hs

@@ -226,10 +226,9 @@ postingDate2 p = fromMaybe nulldate $ asum dates
 -- the ambiguity, unmarked can mean "posting and transaction are both
 -- unmarked" or "posting is unmarked and don't know about the transaction".
 postingStatus :: Posting -> Status
-postingStatus Posting{pstatus=s, ptransaction=mt}
-  | s == Unmarked = case mt of Just t  -> tstatus t
-                               Nothing -> Unmarked
-  | otherwise = s
+postingStatus Posting{pstatus=s, ptransaction=mt} = case s of
+    Unmarked -> maybe Unmarked tstatus mt
+    _ -> s
 
 -- | Tags for this posting including any inherited from its parent transaction.
 postingAllTags :: Posting -> [Tag]

hledger-lib/Hledger/Data/Valuation.hs

@@ -46,7 +46,6 @@ import Hledger.Data.Types
 import Hledger.Data.Amount
 import Hledger.Data.Dates (nulldate)
 import Hledger.Data.Commodity (showCommoditySymbol)
-import Data.Maybe (fromMaybe)
 import Text.Printf (printf)
 
 
@@ -335,7 +334,7 @@ pricesShortestPath start end edges =
     extend (path,unusededges) =
       let
         pathnodes = start : map mpto path
-        pathend = fromMaybe start $ mpto <$> lastMay path
+        pathend = maybe start mpto $ lastMay path
         (nextedges,remainingedges) = partition ((==pathend).mpfrom) unusededges
       in
         [ (path', remainingedges')

hledger-lib/Hledger/Read/JournalReader.hs

@@ -426,7 +426,7 @@ commoditydirectiveonelinep = do
   lift skipNonNewlineSpaces
   _ <- lift followingcommentp
   let comm = Commodity{csymbol=acommodity, cformat=Just $ dbg6 "style from commodity directive" astyle}
-  if asdecimalpoint astyle == Nothing
+  if isNothing $ asdecimalpoint astyle
   then customFailure $ parseErrorAt off pleaseincludedecimalpoint
   else modify' (\j -> j{jcommodities=M.insert acommodity comm $ jcommodities j})
 
@@ -467,7 +467,7 @@ formatdirectivep expectedsym = do
   _ <- lift followingcommentp
   if acommodity==expectedsym
     then
-      if asdecimalpoint astyle == Nothing
+      if isNothing $ asdecimalpoint astyle
       then customFailure $ parseErrorAt off pleaseincludedecimalpoint
       else return $ dbg6 "style from format subdirective" astyle
     else customFailure $ parseErrorAt off $
@@ -544,7 +544,7 @@ defaultcommoditydirectivep = do
   off <- getOffset
   Amount{acommodity,astyle} <- amountp
   lift restofline
-  if asdecimalpoint astyle == Nothing
+  if isNothing $ asdecimalpoint astyle
   then customFailure $ parseErrorAt off pleaseincludedecimalpoint
   else setDefaultCommodityAndStyle (acommodity, astyle)
 

hledger-web/Hledger/Web/Settings.hs

@@ -10,6 +10,7 @@
 module Hledger.Web.Settings where
 
 import Data.Default (def)
+import Data.Maybe (fromMaybe)
 import Data.Text (Text)
 import Data.Yaml
 import Language.Haskell.TH.Syntax (Q, Exp)
@@ -71,9 +72,7 @@ staticDir = "static"
 --
 -- To see how this value is used, see urlRenderOverride in Foundation.hs
 staticRoot :: AppConfig DefaultEnv Extra -> Text
-staticRoot conf = case extraStaticRoot $ appExtra conf of
-                    Just root -> root
-                    Nothing -> [st|#{appRoot conf}/static|]
+staticRoot conf = fromMaybe [st|#{appRoot conf}/static|] . extraStaticRoot $ appExtra conf
 
 -- | Settings for 'widgetFile', such as which template languages to support and
 -- default Hamlet settings.

hledger/Hledger/Cli/Commands/Close.hs

@@ -58,8 +58,8 @@ close CliOpts{rawopts_=rawopts, reportspec_=rspec} j = do
         (o, c)         -> (o, c)
 
     -- descriptions to use for the closing/opening transactions
-    closingdesc = fromMaybe (T.pack defclosingdesc) $ T.pack <$> maybestringopt "close-desc" rawopts
-    openingdesc = fromMaybe (T.pack defopeningdesc) $ T.pack <$> maybestringopt "open-desc" rawopts
+    closingdesc = maybe (T.pack defclosingdesc) T.pack $ maybestringopt "close-desc" rawopts
+    openingdesc = maybe (T.pack defopeningdesc) T.pack $ maybestringopt "open-desc" rawopts
 
     -- accounts to close to and open from
     -- if only one is specified, it is used for both

hledger/Hledger/Cli/DocFiles.hs

@@ -24,6 +24,7 @@ import Prelude ()
 import "base-compat-batteries" Prelude.Compat
 import Data.ByteString (ByteString)
 import qualified Data.ByteString.Char8 as BC
+import Data.Maybe (fromMaybe, isNothing)
 import Data.String
 import System.IO
 import System.IO.Temp
@@ -31,7 +32,6 @@ import System.Process
 
 import Hledger.Utils (first3, second3, third3, embedFileRelative)
 import Text.Printf (printf)
-import Data.Maybe (fromMaybe)
 import System.Environment (lookupEnv)
 import Hledger.Utils.Debug
 
@@ -108,7 +108,7 @@ runPagerForTopic tool mtopic = do
     let defpager = "less -is"
     envpager <- fromMaybe defpager <$> lookupEnv "PAGER"
     -- force the use of less if a topic is provided, since we know how to scroll it
-    let pager = if mtopic==Nothing then envpager else defpager
+    let pager = if isNothing mtopic then envpager else defpager
     callCommand $ dbg1 "pager command" $ 
       pager ++ maybe "" (printf " +'/^(   )?%s'") mtopic ++ " " ++ f