-mkPRepr :: [[Type]] -> VM Type
-mkPRepr [] = return unitTy
-mkPRepr tys
- = do
- embed <- builtin embedTyCon
- cross <- builtin crossTyCon
- plus <- builtin plusTyCon
-
- let mk_embed ty = mkTyConApp embed [ty]
- mk_cross ty1 ty2 = mkTyConApp cross [ty1, ty2]
- mk_plus ty1 ty2 = mkTyConApp plus [ty1, ty2]
-
- mk_tup [] = unitTy
- mk_tup tys = foldr1 mk_cross tys
-
- mk_sum [] = unitTy
- mk_sum tys = foldr1 mk_plus tys
-
- return . mk_sum
- . map (mk_tup . map mk_embed)
- $ tys
-
-mkToPRepr :: [[CoreExpr]] -> VM ([CoreExpr], Type)
-mkToPRepr ess
- = do
- embed_tc <- builtin embedTyCon
- embed_dc <- builtin embedDataCon
- cross_tc <- builtin crossTyCon
- cross_dc <- builtin crossDataCon
- plus_tc <- builtin plusTyCon
- left_dc <- builtin leftDataCon
- right_dc <- builtin rightDataCon
-
- let mk_embed expr
- = (mkConApp embed_dc [Type ty, expr],
- mkTyConApp embed_tc [ty])
- where ty = exprType expr
-
- mk_cross (expr1, ty1) (expr2, ty2)
- = (mkConApp cross_dc [Type ty1, Type ty2, expr1, expr2],
- mkTyConApp cross_tc [ty1, ty2])
-
- mk_tup [] = (Var unitDataConId, unitTy)
- mk_tup es = foldr1 mk_cross es
-
- mk_sum [] = ([Var unitDataConId], unitTy)
- mk_sum [(expr, ty)] = ([expr], ty)
- mk_sum ((expr, lty) : es)
- = let (alts, rty) = mk_sum es
- in
- (mkConApp left_dc [Type lty, Type rty, expr]
- : [mkConApp right_dc [Type lty, Type rty, alt] | alt <- alts],
- mkTyConApp plus_tc [lty, rty])
-
- return . mk_sum $ map (mk_tup . map mk_embed) ess
-
-mkFromPRepr :: CoreExpr -> Type -> [([Var], CoreExpr)] -> VM CoreExpr
-mkFromPRepr scrut res_ty alts
- = do
- embed_dc <- builtin embedDataCon
- cross_dc <- builtin crossDataCon
- left_dc <- builtin leftDataCon
- right_dc <- builtin rightDataCon
- pa_tc <- builtin paTyCon
-
- let un_embed expr ty var res
- = Case expr (mkWildId ty) res_ty
- [(DataAlt embed_dc, [var], res)]
-
- un_cross expr ty var1 var2 res
- = Case expr (mkWildId ty) res_ty
- [(DataAlt cross_dc, [var1, var2], res)]
-
- un_tup expr ty [] res = return res
- un_tup expr ty [var] res = return $ un_embed expr ty var res
- un_tup expr ty (var : vars) res
- = do
- lv <- newLocalVar FSLIT("x") lty
- rv <- newLocalVar FSLIT("y") rty
- liftM (un_cross expr ty lv rv
- . un_embed (Var lv) lty var)
- (un_tup (Var rv) rty vars res)
- where
- (lty, rty) = splitCrossTy ty
-
- un_plus expr ty var1 var2 res1 res2
- = Case expr (mkWildId ty) res_ty
- [(DataAlt left_dc, [var1], res1),
- (DataAlt right_dc, [var2], res2)]
-
- un_sum expr ty [(vars, res)] = un_tup expr ty vars res
- un_sum expr ty ((vars, res) : alts)
- = do
- lv <- newLocalVar FSLIT("l") lty
- rv <- newLocalVar FSLIT("r") rty
- liftM2 (un_plus expr ty lv rv)
- (un_tup (Var lv) lty vars res)
- (un_sum (Var rv) rty alts)
- where
- (lty, rty) = splitPlusTy ty
-
- un_sum scrut (exprType scrut) alts
-