Refactor - Lenses for Ann in Oczor.Syntax.Types (#16)

* Refactor - Lenses for `Ann` in Oczor.Syntax.Types

* Refactor - Lenses for `Ann` in Oczor.Syntax.Types #2

* Refactor - Lenses for `Ann` in Oczor.Syntax.Types #3

* Fix

* Fix #2

* Apply patch

src/Oczor/Compiler/Utl.hs

@@ -46,7 +46,7 @@ compileJsPartTxt x = do
 inferTxt2 x = either (putStrLn . pack . show) (putStrLn . pack . prettyShow) $ inferTxt x
 
 inferType :: Expr -> Either Error TypeExpr
-inferType y = (fst . attr . snd) <$> inferAllExpr baseTypeContext y
+inferType y = (attrType . snd) <$> inferAllExpr baseTypeContext y
 
 inferTxt :: String -> Either Error TypeExpr
 inferTxt x = normalizeType <$> (Parser.parseExpr x >>= inferType)

src/Oczor/Infer/InferAst.hs

@@ -11,7 +11,8 @@ import Oczor.Utl
 type InferExprF = AnnF ExprF (TypeExpr, InferContext)
 type InferExpr = Ann ExprF (TypeExpr, InferContext)
 
-attrType = fst . attr
+attrType :: Ann a (x, y) -> x
+attrType = view (attr . _1)
 
 annType x y = Ann x (y, emptyContext)
 

src/Oczor/Syntax/Ast.hs

@@ -8,6 +8,7 @@
 module Oczor.Syntax.Ast (module Oczor.Syntax.Ast, module Oczor.Syntax.Types, Lits(..), Stmts(..)) where
 
 import ClassyPrelude
+import Control.Lens
 import Data.Functor.Foldable
 import Data.Functor.Foldable.TH
 import Oczor.Syntax.Types
@@ -70,8 +71,11 @@ makeBaseFunctor ''Expr
 
 deriving instance Show a => Show (ExprF a)
 
-data Ann f a = Ann (f (Ann f a)) a deriving (Functor, Foldable, Traversable)
-data AnnF f a r = AnnF (f r) a deriving (Functor, Foldable, Traversable)
+data Ann f a = Ann { _unAnn :: f (Ann f a), _attr :: a } deriving (Functor, Foldable, Traversable)
+data AnnF f a r = AnnF { _unAnnF :: f r, _attrF :: a } deriving (Functor, Foldable, Traversable)
+
+makeLenses ''Ann
+makeLenses ''AnnF
 
 type instance Base (Ann f a) = AnnF f a
 
@@ -85,16 +89,7 @@ instance Show a => Show (Ann ExprF a) where
   show (Ann x y) = "(" ++ show x ++ " ANN " ++ show y ++ ")"
 
 stripAnns :: Ann ExprF a -> Expr
-stripAnns = cata $ \case AnnF x _ -> embed x
-
-attr :: Ann f a -> a
-attr (Ann _ a) = a
-
-unAnn :: Ann f a -> f (Ann f a)
-unAnn (Ann a _) = a
-
-changeAttr :: Ann f a -> a -> Ann f a
-changeAttr (Ann x a) = Ann x
+stripAnns = cata $ embed . view unAnnF
 
 pattern UnAnn x <- Ann x y