From 77b628b79bd179e7dde83d44bbea5acb4c0cb043 Mon Sep 17 00:00:00 2001 From: Łukasz Hanuszczak Date: Sun, 19 Jul 2015 20:30:06 +0200 Subject: Create function for retrieving free variables from given type. --- haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'haddock-api/src/Haddock') diff --git a/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs b/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs index 6a149719..7e568933 100644 --- a/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs +++ b/haddock-api/src/Haddock/Backends/Xhtml/Specialize.hs @@ -159,6 +159,21 @@ renameType HsWildcardTy = pure HsWildcardTy renameType (HsNamedWildcardTy name) = HsNamedWildcardTy <$> renameName name +freeVariables :: forall name. (NamedThing name, Data (HsType name)) + => HsType name -> Set OccName +freeVariables = + everythingWithState Set.empty Set.union query + where + query term ctx = case cast term :: Maybe (HsType name) of + Just (HsForAllTy _ _ bndrs _ _) -> + (Set.empty, Set.union ctx (bndrsNames bndrs)) + Just (HsTyVar name) + | getName name `Set.member` ctx -> (Set.empty, ctx) + | otherwise -> (Set.singleton $ getOccName name, ctx) + _ -> (Set.empty, ctx) + bndrsNames = Set.fromList . map (getName . tyVarName . unLoc) . hsq_tvs + + renameLType :: SetName name => LHsType name -> Rename name (LHsType name) renameLType = located renameType @@ -237,3 +252,8 @@ alternativeNames name = located :: Functor f => (a -> f b) -> Located a -> f (Located b) located f (L loc e) = L loc <$> f e + + +tyVarName :: HsTyVarBndr name -> name +tyVarName (UserTyVar name) = name +tyVarName (KindedTyVar (L _ name) _) = name -- cgit v1.2.3