1 files changed, 48 insertions, 0 deletions
diff --git a/src/Haskell/Env/Cmd.hs b/src/Haskell/Env/Cmd.hs
new file mode 100644
index 0000000..35a6542
--- /dev/null
+++ b/src/Haskell/Env/Cmd.hs
@@ -0,0 +1,48 @@
+module Haskell.Env.Cmd where
+
+import Haskell.AST
+import Haskell.Rewrite
+import Pretty
+import Util
+
+
+data Action = Action RewCmd Name
+  deriving (Show)
+
+data RewCmd = CRewrite Name
+            | CBeta
+            | CEta
+            | CCase
+            | CCaseForce
+            | CEtaCase
+            | CCaseCase
+            | CRepeat RewCmd
+  deriving (Show)
+
+instance Pretty Action where
+    pretty (Action cmd target) = Node ("action " ++ target) [pretty cmd]
+
+instance Pretty RewCmd where
+    pretty (CRewrite name) = Leaf ("rew " ++ name)
+    pretty CBeta = Leaf "beta"
+    pretty CEta = Leaf "eta"
+    pretty CCase = Leaf "case"
+    pretty CCaseForce = Leaf "case!"
+    pretty CEtaCase = Leaf "etacase"
+    pretty CCaseCase = Leaf "casecase"
+    pretty (CRepeat cmd) = Node "repeat" [pretty cmd]
+
+
+exprTransformer :: RewCmd -> Maybe (Expr -> Expr)
+exprTransformer = fmap (normalise .) . exprTransformer'
+
+exprTransformer' :: RewCmd -> Maybe (Expr -> Expr)
+exprTransformer' (CRewrite _) = Nothing
+exprTransformer' CBeta        = Just betared
+exprTransformer' CEta         = Just etared
+exprTransformer' CCase        = Just (casered False)
+exprTransformer' CCaseForce   = Just (casered True)
+exprTransformer' CEtaCase     = Just etacase
+exprTransformer' CCaseCase    = Just casecase
+exprTransformer' (CRepeat (CRepeat cmd)) = exprTransformer' (CRepeat cmd)
+exprTransformer' (CRepeat cmd) = fixpoint <$> exprTransformer' cmd