Replace 'cacheFonts' by more versatile 'withFonts' inspired by 'withResources' that avoid having to declare an inline function to capture the 'layer' argument and pass it twice

examples/getText.hs

@@ -3,7 +3,7 @@ import Control.Monad ((>=>))
 import Control.Monad.IO.Class (liftIO)
 import qualified Data.ByteString.Char8 as BS (readFile)
 import Data.Id (Id(..), mapWithKey)
-import qualified Data.Map as Map (toList)
+import qualified Data.Map as Map (mapWithKey)
 import Data.OrderedMap (mapi)
 import qualified Data.Text as Text (unpack)
 import PDF (UnifiedLayers(..), parseDocument)
@@ -11,7 +11,8 @@ import PDF.Box (Box(..))
 import PDF.Content.Text (Chunks(..))
 import PDF.Layer (Layer)
 import PDF.Pages (
-    Contents(..), FontCache, Page(..), PageNumber(..), Pages(..), cacheFonts, withResources
+      Contents(..), FontCache, Page(..), PageNumber(..), Pages(..), withFonts
+    , withResources
   )
 import System.Environment (getArgs)
 import System.Exit (die)
@@ -31,13 +32,10 @@ displayPage n = withResources (
         printf "p#%d obj#%d instr#%d: %s" n (getId a) (getId b) (Text.unpack v)
 
 getAll :: Layer -> IO ()
-getAll layer =
-    Map.toList <$> r Pages layer
-  >>= cacheFonts layer . mapM_ (uncurry displayPage)
+getAll = withFonts $ r Pages >=> sequence_ . Map.mapWithKey displayPage
 
 get :: Int -> Layer -> IO ()
-get n layer =
-  r (P n) layer >>= cacheFonts layer . displayPage n
+get n = withFonts $ r (P n) >=> displayPage n
 
 onDoc :: FilePath -> (Layer -> IO ()) -> IO ()
 onDoc inputFile f = do

src/PDF/Pages.hs

@@ -9,7 +9,7 @@ module PDF.Pages (
     , Page(..)
     , PageNumber(..)
     , Pages(..)
-    , cacheFonts
+    , withFonts
     , withResources
   ) where
 
@@ -149,8 +149,8 @@ instance Monad m => Box m Contents Page (OrderedMap (Id Object) Content) where
   r Contents = return . contents
   w _ contents page = return $ page {contents}
 
-cacheFonts :: Monad m => Layer -> FontCache m a -> m a
-cacheFonts layer = flip runReaderT layer . flip evalStateT Map.empty
+withFonts :: Monad m => (Layer -> FontCache m a) -> Layer -> m a
+withFonts f layer = runReaderT (evalStateT (f layer) Map.empty) layer
 
 withResources :: Except m => (Page -> ReaderT FontSet m b) -> Page -> FontCache m b
 withResources f p =