Move module hierarchy under CHAD.

1 files changed, 19 insertions, 0 deletions

diff --git a/src/CHAD/Util/IdGen.hs b/src/CHAD/Util/IdGen.hs
new file mode 100644
index 0000000..d4fd945
--- /dev/null
+++ b/src/CHAD/Util/IdGen.hs
@@ -0,0 +1,19 @@
+{-# LANGUAGE DerivingStrategies #-}
+{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+module CHAD.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, MonadFix)
+
+genId :: IdGen Int
+genId = IdGen (state (\i -> (i, i + 1)))
+
+runIdGen :: Int -> IdGen a -> a
+runIdGen start (IdGen m) = evalState m start
+
+runIdGen' :: Int -> IdGen a -> (a, Int)
+runIdGen' start (IdGen m) = runState m start