----------------------------------------------------------------------
- UsageTy
- ~~~~~~~
-
-Constructing and taking apart usage types.
-
-\begin{code}
-mkUTy :: Type -> Type -> Type
-mkUTy u ty
- = ASSERT2( typeKind u `eqKind` usageTypeKind,
- ptext SLIT("mkUTy:") <+> pprType u <+> pprType ty )
- UASSERT2( not (isUTy ty), ptext SLIT("mkUTy:") <+> pprType u <+> pprType ty )
- -- if u == usMany then ty else : ToDo? KSW 2000-10
-#ifdef DO_USAGES
- UsageTy u ty
-#else
- ty
-#endif
-
-splitUTy :: Type -> (Type {- :: $ -}, Type)
-splitUTy orig_ty
- = case splitUTy_maybe orig_ty of
- Just (u,ty) -> (u,ty)
-#ifdef DO_USAGES
- Nothing -> pprPanic "splitUTy:" (pprType orig_ty)
-#else
- Nothing -> (usMany,orig_ty) -- default annotation ToDo KSW 2000-10
-#endif
-
-splitUTy_maybe :: Type -> Maybe (Type {- :: $ -}, Type)
-splitUTy_maybe (UsageTy u ty) = Just (u,ty)
-splitUTy_maybe (NoteTy _ ty) = splitUTy_maybe ty
-splitUTy_maybe other_ty = Nothing
-
-isUTy :: Type -> Bool
- -- has usage annotation
-isUTy = maybeToBool . splitUTy_maybe
-
-uaUTy :: Type -> Type
- -- extract annotation
-uaUTy = fst . splitUTy
-
-unUTy :: Type -> Type
- -- extract unannotated type
-unUTy = snd . splitUTy
-\end{code}
-
-\begin{code}
-liftUTy :: (Type -> Type) -> Type -> Type
- -- lift outer usage annot over operation on unannotated types
-liftUTy f ty
- = let
- (u,ty') = splitUTy ty
- in
- mkUTy u (f ty')
-\end{code}
-
-\begin{code}
-mkUTyM :: Type -> Type
- -- put TOP (no info) annotation on unannotated type
-mkUTyM ty = mkUTy usMany ty
-\end{code}
-
-\begin{code}
-isUsageKind :: Kind -> Bool
-isUsageKind k
- = ASSERT( typeKind k `eqKind` superKind )
- k `eqKind` usageTypeKind
-
-isUsage :: Type -> Bool
-isUsage ty
- = isUsageKind (typeKind ty)
-
-isUTyVar :: Var -> Bool
-isUTyVar v
- = isUsageKind (tyVarKind v)
-\end{code}
-
-