lib: Replace some utility functions with library functions.

hledger-lib/Hledger/Data/Dates.hs

@@ -84,6 +84,7 @@ import Control.Applicative.Permutations
 import Control.Monad (guard, unless)
 import "base-compat-batteries" Data.List.Compat
 import Data.Default
+import Data.Foldable (asum)
 import Data.Maybe
 import qualified Data.Set as Set
 import Data.Text (Text)
@@ -654,7 +655,7 @@ advancetonthweekday n wd s =
 
 -- -- | Parse a couple of date-time string formats to a time type.
 -- parsedatetimeM :: String -> Maybe LocalTime
--- parsedatetimeM s = firstJust [
+-- parsedatetimeM s = asum [
 --     parseTime defaultTimeLocale "%Y/%m/%d %H:%M:%S" s,
 --     parseTime defaultTimeLocale "%Y-%m-%d %H:%M:%S" s
 --     ]
@@ -672,9 +673,9 @@ parsetime =
 -- `YYYY-MM-DD`, `YYYY/MM/DD` or `YYYY.MM.DD`, with leading zeros required.
 -- For internal use, not quite the same as the journal's "simple dates".
 parsedateM :: String -> Maybe Day
-parsedateM s = firstJust [
+parsedateM s = asum [
-     parsetime defaultTimeLocale "%Y/%m/%d" s,
      parsetime defaultTimeLocale "%Y-%m-%d" s,
+     parsetime defaultTimeLocale "%Y/%m/%d" s,
      parsetime defaultTimeLocale "%Y.%m.%d" s
      ]
 

hledger-lib/Hledger/Read.hs

@@ -49,6 +49,7 @@ import qualified Control.Exception as C
 import Control.Monad (when)
 import "mtl" Control.Monad.Except (runExceptT)
 import Data.Default
+import Data.Foldable (asum)
 import Data.List
 import Data.Maybe
 import Data.Ord
@@ -170,7 +171,7 @@ readJournalFile :: InputOpts -> PrefixedFilePath -> IO (Either String Journal)
 readJournalFile iopts prefixedfile = do
   let
     (mfmt, f) = splitReaderPrefix prefixedfile
-    iopts' = iopts{mformat_=firstJust [mfmt, mformat_ iopts]}
+    iopts' = iopts{mformat_=asum [mfmt, mformat_ iopts]}
   requireJournalFileExists f
   t <- readFileOrStdinPortably f
     -- <- T.readFile f  -- or without line ending translation, for testing

hledger-lib/Hledger/Read/CsvReader.hs

@@ -1152,7 +1152,7 @@ csvFieldValue rules record fieldname = do
 -- the "simple date" formats (YYYY/MM/DD, YYYY-MM-DD, YYYY.MM.DD, leading
 -- zeroes optional).
 parseDateWithCustomOrDefaultFormats :: Maybe DateFormat -> String -> Maybe Day
-parseDateWithCustomOrDefaultFormats mformat s = firstJust $ map parsewith formats
+parseDateWithCustomOrDefaultFormats mformat s = asum $ map parsewith formats
   where
     parsetime =
 #if MIN_VERSION_time(1,5,0)

hledger-lib/Hledger/Read/JournalReader.hs

@@ -82,6 +82,7 @@ import Control.Monad.IO.Class (MonadIO, liftIO)
 import Control.Monad.Except (ExceptT(..), runExceptT)
 import Control.Monad.State.Strict (get,modify',put)
 import Control.Monad.Trans.Class (lift)
+import Data.Either (isRight)
 import qualified Data.Map.Strict as M
 #if !(MIN_VERSION_base(4,11,0))
 import Data.Monoid ((<>))

hledger-lib/Hledger/Utils.hs

@@ -146,13 +146,6 @@ getCurrentZonedTime = do
 
 instance Default Bool where def = False
 
-isLeft :: Either a b -> Bool
-isLeft (Left _) = True
-isLeft _        = False
-
-isRight :: Either a b -> Bool
-isRight = not . isLeft
-
 -- | Apply a function the specified number of times,
 -- which should be > 0 (otherwise does nothing).
 -- Possibly uses O(n) stack ?
@@ -178,10 +171,6 @@ expandHomePath = \case
     ('~':_)      -> ioError $ userError "~USERNAME in paths is not supported"
     p            -> return p
 
-firstJust ms = case dropWhile (==Nothing) ms of
-    [] -> Nothing
-    (md:_) -> md
-
 -- | Read text from a file,
 -- converting any \r\n line endings to \n,,
 -- using the system locale's text encoding,

hledger/Hledger/Cli/CliOptions.hs

@@ -73,6 +73,7 @@ import qualified Control.Exception as C
 import Control.Monad (when)
 import Data.Char
 import Data.Default
+import Data.Either (isRight)
 import Data.Functor.Identity (Identity)
 import "base-compat-batteries" Data.List.Compat
 import Data.List.Extra (nubSort)

hledger/Hledger/Cli/Commands/Add.hs

@@ -23,6 +23,7 @@ import Control.Monad.Trans.Class
 import Control.Monad.State.Strict (evalState, evalStateT)
 import Control.Monad.Trans (liftIO)
 import Data.Char (toUpper, toLower)
+import Data.Either (isRight)
 import Data.Functor.Identity (Identity(..))
 import "base-compat-batteries" Data.List.Compat
 import qualified Data.Set as S