Compatibility with old containers lib

hablo.cabal

@@ -1,4 +1,4 @@
-cabal-version:       2.4
+cabal-version:       >= 1.10
 -- Initial package description 'hablo.cabal' generated by 'cabal init'.
 -- For further documentation, see http://haskell.org/cabal/users-guide/
 
@@ -8,7 +8,7 @@ synopsis:            A minimalist static blog generator
 -- description:
 homepage:            https://git.marvid.fr/Tissevert/hablo
 -- bug-reports:
-license:             BSD-3-Clause
+license:             BSD3
 license-file:        LICENSE
 author:              Tissevert
 maintainer:          tissevert+devel@marvid.fr
@@ -38,7 +38,7 @@ executable hablo
                      , Pretty
   -- other-extensions:
   build-depends:       aeson
-                     , base ^>=4.12.0.0
+                     , base <4.12.0.0
                      , bytestring
                      , containers
                      , directory
@@ -51,6 +51,6 @@ executable hablo
                      , text
                      , time
                      , unix
-  ghc-options:         -Wall
+  ghc-options:         -Wall -dynamic
   hs-source-dirs:      src
   default-language:    Haskell2010

src/Blog.hs

@@ -22,11 +22,12 @@ import qualified Blog.Wording as Wording (build)
 import Control.Monad ((>=>), filterM, forM)
 import Control.Monad.Reader (MonadReader, ask)
 import Data.Either (rights)
-import Data.Map (Map, (!?))
+import Data.Map (Map, lookup)
 import qualified Data.Map as Map (fromList)
 import Data.Set (Set)
 import qualified Data.Set as Set (empty, null, singleton, union)
 import qualified Files (find)
+import Prelude hiding (lookup)
 import System.Directory (doesFileExist, withCurrentDirectory)
 import System.FilePath ((</>), dropTrailingPathSeparator, takeExtension, takeFileName)
 
@@ -62,7 +63,7 @@ tagged collection path = do
     fileExists <- doesFileExist link
     return $ if fileExists
       then let articleKey = Article.getKey link in
-        maybe Set.empty (\_ -> Set.singleton articleKey) (collection !? articleKey)
+        maybe Set.empty (\_ -> Set.singleton articleKey) (lookup articleKey collection)
       else Set.empty
   return (takeFileName path, foldl Set.union Set.empty keys)