From e8707f485ff4ec701dbe07f8893b8798277b1afe Mon Sep 17 00:00:00 2001 From: Twan van Laarhoven Date: Thu, 17 Jan 2008 20:46:03 +0000 Subject: [PATCH] Monadify typecheck/TcExpr: use do, return and standard monad functions --- compiler/typecheck/TcExpr.lhs | 79 +++++++++++++++++++++-------------------- 1 file changed, 40 insertions(+), 39 deletions(-) diff --git a/compiler/typecheck/TcExpr.lhs b/compiler/typecheck/TcExpr.lhs index ebbb738..b4abd3d 100644 --- a/compiler/typecheck/TcExpr.lhs +++ b/compiler/typecheck/TcExpr.lhs @@ -57,6 +57,8 @@ import ListSetOps import Maybes import Outputable import FastString + +import Control.Monad \end{code} %************************************************************************ @@ -94,11 +96,11 @@ tcPolyExprNC expr res_ty --------------- tcPolyExprs :: [LHsExpr Name] -> [TcType] -> TcM [LHsExpr TcId] -tcPolyExprs [] [] = returnM [] +tcPolyExprs [] [] = return [] tcPolyExprs (expr:exprs) (ty:tys) = do { expr' <- tcPolyExpr expr ty ; exprs' <- tcPolyExprs exprs tys - ; returnM (expr':exprs') } + ; return (expr':exprs') } tcPolyExprs exprs tys = pprPanic "tcPolyExprs" (ppr exprs $$ ppr tys) --------------- @@ -139,10 +141,10 @@ tcExpr (HsPar expr) res_ty = do { expr' <- tcMonoExpr expr res_ty ; return (HsPar expr') } tcExpr (HsSCC lbl expr) res_ty = do { expr' <- tcMonoExpr expr res_ty - ; returnM (HsSCC lbl expr') } + ; return (HsSCC lbl expr') } tcExpr (HsTickPragma info expr) res_ty = do { expr' <- tcMonoExpr expr res_ty - ; returnM (HsTickPragma info expr') } + ; return (HsTickPragma info expr') } tcExpr (HsCoreAnn lbl expr) res_ty -- hdaume: core annotation = do { expr' <- tcMonoExpr expr res_ty @@ -290,15 +292,15 @@ tcExpr (HsDo do_or_lc stmts body _) res_ty tcExpr in_expr@(ExplicitList _ exprs) res_ty -- Non-empty list = do { (elt_ty, coi) <- boxySplitListTy res_ty - ; exprs' <- mappM (tc_elt elt_ty) exprs + ; exprs' <- mapM (tc_elt elt_ty) exprs ; return $ mkHsWrapCoI coi (ExplicitList elt_ty exprs') } where tc_elt elt_ty expr = tcPolyExpr expr elt_ty tcExpr in_expr@(ExplicitPArr _ exprs) res_ty -- maybe empty = do { (elt_ty, coi) <- boxySplitPArrTy res_ty - ; exprs' <- mappM (tc_elt elt_ty) exprs - ; ifM (null exprs) (zapToMonotype elt_ty) + ; exprs' <- mapM (tc_elt elt_ty) exprs + ; when (null exprs) (zapToMonotype elt_ty >> return ()) -- If there are no expressions in the comprehension -- we must still fill in the box -- (Not needed for [] and () becuase they happen @@ -361,7 +363,7 @@ tcExpr expr@(RecordCon (L loc con_name) _ rbinds) res_ty ; (con_expr, rbinds') <- tcIdApp con_name arity check_fields res_ty - ; returnM (RecordCon (L loc (dataConWrapId data_con)) con_expr rbinds') } + ; return (RecordCon (L loc (dataConWrapId data_con)) con_expr rbinds') } -- The main complication with RecordUpd is that we need to explicitly -- handle the *non-updated* fields. Consider: @@ -396,14 +398,14 @@ tcExpr expr@(RecordCon (L loc con_name) _ rbinds) res_ty -- don't know how to do the update otherwise. -tcExpr expr@(RecordUpd record_expr rbinds _ _ _) res_ty - = -- STEP 0 +tcExpr expr@(RecordUpd record_expr rbinds _ _ _) res_ty = do + -- STEP 0 -- Check that the field names are really field names let field_names = hsRecFields rbinds - in - ASSERT( notNull field_names ) - mappM tcLookupField field_names `thenM` \ sel_ids -> + + MASSERT( notNull field_names ) + sel_ids <- mapM tcLookupField field_names -- The renamer has already checked that they -- are all in scope let @@ -412,8 +414,8 @@ tcExpr expr@(RecordUpd record_expr rbinds _ _ _) res_ty not (isRecordSelector sel_id), -- Excludes class ops let L loc field_name = hsRecFieldId fld ] - in - checkM (null bad_guys) (sequenceM bad_guys `thenM_` failM) `thenM_` + + unless (null bad_guys) (sequence bad_guys >> failM) -- STEP 1 -- Figure out the tycon and data cons from the first field name @@ -426,18 +428,17 @@ tcExpr expr@(RecordUpd record_expr rbinds _ _ _) res_ty relevant_cons = filter is_relevant data_cons is_relevant con = all (`elem` dataConFieldLabels con) field_names - in -- STEP 2 -- Check that at least one constructor has all the named fields -- i.e. has an empty set of bad fields returned by badFields checkTc (not (null relevant_cons)) - (badFieldsUpd rbinds) `thenM_` + (badFieldsUpd rbinds) -- Check that all relevant data cons are vanilla. Doing record updates on -- GADTs and/or existentials is more than my tiny brain can cope with today checkTc (all isVanillaDataCon relevant_cons) - (nonVanillaUpd tycon) `thenM_` + (nonVanillaUpd tycon) -- STEP 4 -- Use the un-updated fields to find a vector of booleans saying @@ -457,12 +458,12 @@ tcExpr expr@(RecordUpd record_expr rbinds _ _ _) res_ty is_common_tv tv = tv `elemVarSet` common_tyvars mk_inst_ty tv result_inst_ty - | is_common_tv tv = returnM result_inst_ty -- Same as result type + | is_common_tv tv = return result_inst_ty -- Same as result type | otherwise = newFlexiTyVarTy (tyVarKind tv) -- Fresh type, of correct kind - in - ASSERT( null theta ) -- Vanilla datacon - tcInstTyVars con1_tyvars `thenM` \ (_, result_inst_tys, result_inst_env) -> - zipWithM mk_inst_ty con1_tyvars result_inst_tys `thenM` \ scrut_inst_tys -> + + MASSERT( null theta ) -- Vanilla datacon + (_, result_inst_tys, result_inst_env) <- tcInstTyVars con1_tyvars + scrut_inst_tys <- zipWithM mk_inst_ty con1_tyvars result_inst_tys -- STEP 3: Typecheck the update bindings. -- Do this after checking for bad fields in case @@ -471,9 +472,9 @@ tcExpr expr@(RecordUpd record_expr rbinds _ _ _) res_ty result_ty = substTy result_inst_env con1_res_ty con1_arg_tys' = map (substTy result_inst_env) con1_arg_tys origin = RecordUpdOrigin - in - tcSubExp origin result_ty res_ty `thenM` \ co_fn -> - tcRecordBinds con1 con1_arg_tys' rbinds `thenM` \ rbinds' -> + + co_fn <- tcSubExp origin result_ty res_ty + rbinds' <- tcRecordBinds con1 con1_arg_tys' rbinds -- STEP 5: Typecheck the expression to be updated let @@ -481,8 +482,8 @@ tcExpr expr@(RecordUpd record_expr rbinds _ _ _) res_ty scrut_ty = substTy scrut_inst_env con1_res_ty -- This is one place where the isVanilla check is important -- So that inst_tys matches the con1_tyvars - in - tcMonoExpr record_expr scrut_ty `thenM` \ record_expr' -> + + record_expr' <- tcMonoExpr record_expr scrut_ty -- STEP 6: Figure out the LIE we need. -- We have to generate some dictionaries for the data type context, @@ -491,17 +492,17 @@ tcExpr expr@(RecordUpd record_expr rbinds _ _ _) res_ty -- What dictionaries do we need? The dataConStupidTheta tells us. let theta' = substTheta scrut_inst_env (dataConStupidTheta con1) - in - instStupidTheta origin theta' `thenM_` + + instStupidTheta origin theta' -- Step 7: make a cast for the scrutinee, in the case that it's from a type family let scrut_co | Just co_con <- tyConFamilyCoercion_maybe tycon = WpCo $ mkTyConApp co_con scrut_inst_tys | otherwise = idHsWrapper - in + -- Phew! - returnM (mkHsWrap co_fn (RecordUpd (mkLHsWrap scrut_co record_expr') rbinds' + return (mkHsWrap co_fn (RecordUpd (mkLHsWrap scrut_co record_expr') rbinds' relevant_cons scrut_inst_tys result_inst_tys)) \end{code} @@ -1086,7 +1087,7 @@ tcRecordBinds -> TcM (HsRecordBinds TcId) tcRecordBinds data_con arg_tys (HsRecFields rbinds dd) - = do { mb_binds <- mappM do_bind rbinds + = do { mb_binds <- mapM do_bind rbinds ; return (HsRecFields (catMaybes mb_binds) dd) } where flds_w_tys = zipEqual "tcRecordBinds" (dataConFieldLabels data_con) arg_tys @@ -1109,14 +1110,14 @@ checkMissingFields data_con rbinds -- Illegal if any arg is strict addErrTc (missingStrictFields data_con []) else - returnM () + return () - | otherwise -- A record - = checkM (null missing_s_fields) - (addErrTc (missingStrictFields data_con missing_s_fields)) `thenM_` + | otherwise = do -- A record + unless (null missing_s_fields) + (addErrTc (missingStrictFields data_con missing_s_fields)) - doptM Opt_WarnMissingFields `thenM` \ warn -> - checkM (not (warn && notNull missing_ns_fields)) + warn <- doptM Opt_WarnMissingFields + unless (not (warn && notNull missing_ns_fields)) (warnTc True (missingFields data_con missing_ns_fields)) where -- 1.7.10.4