resolve named data in case exprs

src/Core/Parse.y

@@ -85,8 +85,8 @@ Program         : ScTypeSig ';' Program         { insTypeSig $1 $3 }
                 | ScTypeSig OptSemi             { singletonTypeSig $1 }
                 | ScDef     ';' Program         { insScDef $1 $3 }
                 | ScDef     OptSemi             { singletonScDef $1 }
-                | TLPragma  ';' Program         {% doTLPragma $1 $3 }
+                | TLPragma  Program             {% doTLPragma $1 $2 }
-                | TLPragma  OptSemi             {% doTLPragma $1 mempty }
+                | TLPragma                      {% doTLPragma $1 mempty }
 
 TLPragma        :: { Pragma }
                 : '{-#' Words '#-}'             { Pragma $2 }
@@ -106,7 +106,6 @@ ScDefs          :: { [ScDef Name] }
 ScDefs          : ScDef ';' ScDefs              { $1 : $3 }
                 | ScDef ';'                     { [$1] }
                 | ScDef                         { [$1] }
-                | {- epsilon -}                 { [] }
 
 ScDef           :: { ScDef Name }
 ScDef           : Var ParList '=' Expr          { ScDef $1 $2 $4 }

src/Core/Syntax.hs

@@ -6,8 +6,13 @@ Description : Core ASTs and the like
 {-# LANGUAGE FunctionalDependencies #-}
 {-# LANGUAGE TemplateHaskell #-}
 {-# LANGUAGE DerivingStrategies, DerivingVia #-}
+-- for recursion-schemes
+{-# LANGUAGE DeriveFunctor, DeriveFoldable, DeriveTraversable
+  , TemplateHaskell, TypeFamilies #-}
 module Core.Syntax
     ( Expr(..)
+    , ExprF(..)
+    , ExprF'(..)
     , Type(..)
     , pattern TyInt
     , Lit(..)
@@ -43,6 +48,8 @@ import Data.Coerce
 import Data.Pretty
 import Data.List                    (intersperse)
 import Data.Function                ((&))
+import Data.Functor.Foldable
+import Data.Functor.Foldable.TH     (makeBaseFunctor)
 import Data.String
 import Data.HashMap.Strict          (HashMap)
 import Data.HashMap.Strict          qualified as H
@@ -142,8 +149,11 @@ data Program b = Program
         via Generically (Program b)
 
 makeLenses ''Program
+makeBaseFunctor ''Expr
 pure []
 
+type ExprF' = ExprF Name
+
 type Program' = Program Name
 type Expr' = Expr Name
 type ScDef' = ScDef Name
@@ -193,3 +203,8 @@ instance HasLHS (ScDef b) (ScDef b) (b, [b]) (b, [b]) where
         (\ (ScDef n as _) -> (n,as))
         (\ (ScDef _ _ e) (n',as') -> (ScDef n' as' e))
 
+instance HasLHS (Binding b) (Binding b) b b where
+    _lhs = lens
+        (\ (k := _) -> k)
+        (\ (_ := e) k' -> k' := e)
+

src/Core/Utils.hs

@@ -1,16 +1,10 @@
--- for recursion schemes
-{-# LANGUAGE DeriveFunctor, DeriveFoldable, DeriveTraversable #-}
--- for recursion schemes
-{-# LANGUAGE TemplateHaskell, TypeFamilies #-}
-
 module Core.Utils
-    ( bindersOf
+    ( programRhss
-    , rhssOf
+    , programGlobals
     , isAtomic
     -- , insertModule
     , extractProgram
     , freeVariables
-    , ExprF(..)
     )
     where
 ----------------------------------------------------------------------------------
@@ -23,13 +17,11 @@ import Lens.Micro
 import GHC.Exts                     (IsList(..))
 ----------------------------------------------------------------------------------
 
-bindersOf :: (IsList l, Item l ~ b) => [Binding b] -> l
+programGlobals :: Traversal' (Program b) b
-bindersOf bs = fromList $ fmap f bs
+programGlobals = programScDefs . each . _lhs . _1
-    where f (k := _) = k
 
-rhssOf :: (IsList l, Item l ~ Expr b) => [Binding b] -> l
+programRhss :: Traversal' (Program b) (Expr b)
-rhssOf = fromList . fmap f
+programRhss = programScDefs . each . _rhs
-    where f (_ := v) = v
 
 isAtomic :: Expr b -> Bool
 isAtomic (Var _)  = True
@@ -47,8 +39,6 @@ extractProgram (Module _ p) = p
 
 ----------------------------------------------------------------------------------
 
-makeBaseFunctor ''Expr
-
 freeVariables :: Expr' -> Set Name
 freeVariables = cata go
     where
@@ -57,8 +47,8 @@ freeVariables = cata go
         -- TODO: collect free vars in rhss of bs
         go (LetF _ bs e)    = (e `S.union` esFree) `S.difference` ns
             where
-                es = rhssOf bs :: [Expr']
+                es = bs ^.. each . _rhs :: [Expr']
-                ns = bindersOf bs
+                ns = S.fromList $ bs ^.. each . _lhs
                 -- TODO: this feels a little wrong. maybe a different scheme is
                 -- appropriate
                 esFree = foldMap id $ freeVariables <$> es

src/Core2Core.hs

@@ -1,3 +1,4 @@
+{-# LANGUAGE ImplicitParams #-}
 {-# LANGUAGE LambdaCase #-}
 module Core2Core
     ( core2core
@@ -18,8 +19,9 @@ import Control.Monad.Writer
 import Control.Monad.State.Lazy
 import Control.Arrow            ((>>>))
 import Data.Text                qualified as T
+import Data.HashMap.Strict      (HashMap)
 import Numeric                  (showHex)
-import Lens.Micro
+import Lens.Micro.Platform
 import Core.Syntax
 import Core.Utils
 ----------------------------------------------------------------------------------
@@ -28,19 +30,35 @@ core2core :: Program' -> Program'
 core2core p = undefined
 
 gmPrep :: Program' -> Program'
-gmPrep p = p & traverseOf rhss (floatNonStrictCases globals)
+gmPrep p = p & appFloater (floatNonStrictCases globals)
-             & runFloater
+             & tagData
-             & \ (me,caseScs) -> me & programScDefs %~ (<>caseScs)
     where
-        rhss :: Traversal' (Program z) (Expr z)
-        rhss = programScDefs . each . _rhs
-
         globals = p ^.. programScDefs . each . _lhs . _1
                 & S.fromList
 
+tagData :: Program' -> Program'
+tagData p = let ?dt = p ^. programDataTags
+            in p & programRhss %~ cata go where
+    go :: (?dt :: HashMap Name (Tag, Int)) => ExprF' Expr' -> Expr'
+    go (CaseF  e as)    = Case e (tagAlts <$> as)
+    go x                = embed x
+
+    tagAlts :: (?dt :: HashMap Name (Tag, Int)) => Alter' -> Alter'
+    tagAlts (Alter (AltData c) bs e) = Alter (AltTag tag) bs e
+        where tag = case ?dt ^. at c of
+                Just (t,_) -> t
+                -- TODO: errorful
+                Nothing    -> error $ "unknown constructor " <> show c
+    tagAlts x = x
+
 -- | Auxilary type used in @floatNonSrictCases@
 type Floater = StateT [Name] (Writer [ScDef'])
 
+appFloater :: (Expr' -> Floater Expr') -> Program' -> Program'
+appFloater fl p = p & traverseOf programRhss fl
+                    & runFloater
+                    & \ (me,floats) -> me & programScDefs %~ (<>floats)
+
 runFloater :: Floater a -> (a, [ScDef'])
 runFloater = flip evalStateT ns >>> runWriter
     where