1 files changed, 61 insertions, 0 deletions
diff --git a/src/CC/Term/Raw.idr b/src/CC/Term/Raw.idr
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+++ b/src/CC/Term/Raw.idr
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+module CC.Term.Raw
+
+import CC.Name
+import CC.Term
+
+import Data.DPair
+import Data.List1
+
+-- Definition ------------------------------------------------------------------
+
+public export
+data RawTerm : Type where
+  RVar : (n : Name) -> RawTerm
+  RAbs : (n : Name) -> RawTerm -> RawTerm
+  RApp : RawTerm -> RawTerm -> RawTerm
+  RLet : (n : Name) -> RawTerm -> RawTerm -> RawTerm
+
+%name RawTerm t, u
+
+-- Error Type ------------------------------------------------------------------
+
+export
+data NameError : Type -> Type where
+  Ok : ty -> NameError ty
+  Err : List1 Name -> NameError ty
+
+export
+Functor NameError where
+  map f (Ok v) = Ok (f v)
+  map f (Err errs) = Err errs
+
+export
+Applicative NameError where
+  pure = Ok
+
+  Ok f <*> Ok v = Ok (f v)
+  Ok f <*> Err ys = Err ys
+  Err xs <*> Ok v = Err xs
+  Err xs <*> Err ys = Err (xs ++ ys)
+
+export
+runNameError : NameError ty -> Either (List1 Name) ty
+runNameError (Ok x) = Right x
+runNameError (Err xs) = Left xs
+
+-- Translation -----------------------------------------------------------------
+
+export
+lookup : (ctx : Context) -> (n : Name) -> NameError $ Subset Nat (\k => IsVar k n ctx)
+lookup [<] n = Err (n ::: [])
+lookup (ctx :< m) n =
+  case decEquiv n m of
+    Yes eq => Ok (Element 0 (Here eq))
+    No _ => map (\p => Element (S p.fst) (There p.snd)) (lookup ctx n)
+
+export
+translate : (ctx : Context) -> RawTerm -> NameError (Term ctx)
+translate ctx (RVar n) = (\p => Var p.fst n p.snd) <$> lookup ctx n
+translate ctx (RAbs n t) = pure (Abs n) <*> translate (ctx :< n) t
+translate ctx (RApp t u) = [| App (translate ctx t) (translate ctx u) |]
+translate ctx (RLet n t u) = pure (Let n) <*> translate ctx t <*> translate (ctx :< n) u