Handle pages parameter : use custom value provided with the usual checks or default it to «pages/» iif the directory exists, otherwise pages are deactivated

src/Blog/Path.hs

@@ -12,6 +12,7 @@ import Data.Aeson (ToJSON(..), (.=), pairs)
 import Data.Monoid ((<>))
 import Files (File(..), filePath)
 import GHC.Generics (Generic)
+import System.Directory (doesDirectoryExist)
 
 data Path = Path {
       articlesPath :: FilePath
@@ -28,10 +29,16 @@ instance ToJSON Path where
       <> "pagesPath" .= pagesPath
     )
 
+getPagesPath :: Maybe FilePath -> IO (Maybe FilePath)
+getPagesPath Nothing = do
+  checkPagesPath <- doesDirectoryExist "pages"
+  return $ if checkPagesPath then Just "pages" else Nothing
+getPagesPath (Just p) = Just <$> (filePath $ Dir p)
+
 build :: FilePath -> Arguments -> IO Path
 build root arguments = do
   articlesPath <- filePath . Dir $ Arguments.articlesPath arguments
-  pagesPath <- mapM (filePath . Dir) $ Arguments.pagesPath arguments
+  pagesPath <- getPagesPath $ Arguments.pagesPath arguments
   remarkableConfig <- mapM (filePath . File) $ Arguments.remarkableConfig arguments
   return $ Path {
       articlesPath, commentsAt, pagesPath, remarkableConfig, root