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Diffstat (limited to 'src/Util/IdGen.hs')
| -rw-r--r-- | src/Util/IdGen.hs | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/Util/IdGen.hs b/src/Util/IdGen.hs index fcfb6e7..3f6611d 100644 --- a/src/Util/IdGen.hs +++ b/src/Util/IdGen.hs @@ -2,11 +2,12 @@ {-# LANGUAGE GeneralizedNewtypeDeriving #-} module Util.IdGen where +import Control.Monad.Fix import Control.Monad.Trans.State.Strict newtype IdGen a = IdGen (State Int a) - deriving newtype (Functor, Applicative, Monad) + deriving newtype (Functor, Applicative, Monad, MonadFix) genId :: IdGen Int genId = IdGen (state (\i -> (i, i + 1))) |