-mkFromPRepr :: CoreExpr -> Type -> [([Var], CoreExpr)] -> VM CoreExpr
-mkFromPRepr scrut res_ty alts
- = do
- sum_tcs <- builtins sumTyCon
- prod_tcs <- builtins prodTyCon
-
- let un_sum expr ty [(vars, res)] = un_prod expr ty vars res
- un_sum expr ty bs
- = do
- ps <- mapM (newLocalVar FSLIT("p")) tys
- bodies <- sequence
- $ zipWith4 un_prod (map Var ps) tys vars rs
- return . Case expr (mkWildId ty) res_ty
- $ zipWith3 mk_alt sum_dcs ps bodies
- where
- (vars, rs) = unzip bs
- tys = splitFixedTyConApp sum_tc ty
- sum_tc = sum_tcs $ length bs
- sum_dcs = tyConDataCons sum_tc
-
- mk_alt dc p body = (DataAlt dc, [p], body)
-
- un_prod expr ty [] r = return r
- un_prod expr ty [var] r = return $ Let (NonRec var expr) r
- un_prod expr ty vars r
- = return $ Case expr (mkWildId ty) res_ty
- [(DataAlt prod_dc, vars, r)]
- where
- prod_tc = prod_tcs $ length vars
- [prod_dc] = tyConDataCons prod_tc
-
- un_sum scrut (exprType scrut) alts
-