X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypes%2FFamInstEnv.lhs;h=60b55d10ce08c6c7b90b814062b3c9f6d51f0cff;hb=ff5ae6ab8ed907dcf6adc810791b756bab827ab3;hp=b851ec1ee64d83c4ea8f27d159b5c0a738cc8f00;hpb=3a2b38084cfea1c88009c4d9236fa403bdda25b4;p=ghc-hetmet.git diff --git a/compiler/types/FamInstEnv.lhs b/compiler/types/FamInstEnv.lhs index b851ec1..60b55d1 100644 --- a/compiler/types/FamInstEnv.lhs +++ b/compiler/types/FamInstEnv.lhs @@ -46,13 +46,19 @@ import Maybe \begin{code} data FamInst = FamInst { fi_fam :: Name -- Family name + -- INVARIANT: fi_fam = case tyConFamInst_maybe fi_tycon of + -- Just (tc, tys) -> tc -- Used for "rough matching"; same idea as for class instances , fi_tcs :: [Maybe Name] -- Top of type args + -- INVARIANT: fi_tcs = roughMatchTcs is_tys -- Used for "proper matching"; ditto , fi_tvs :: TyVarSet -- Template tyvars for full match , fi_tys :: [Type] -- Full arg types + -- INVARIANT: fi_tvs = tyConTyVars fi_tycon + -- fi_tys = case tyConFamInst_maybe fi_tycon of + -- Just (_, tys) -> tys , fi_tycon :: TyCon -- Representation tycon } @@ -82,8 +88,7 @@ pprFamInstHdr :: FamInst -> SDoc pprFamInstHdr (FamInst {fi_fam = fam, fi_tys = tys, fi_tycon = tycon}) = pprTyConSort <+> pprHead where - pprHead = parenSymOcc (getOccName fam) (ppr fam) <+> - sep (map pprParendType tys) + pprHead = pprTypeApp (parenSymOcc (getOccName fam) (ppr fam)) tys pprTyConSort | isDataTyCon tycon = ptext SLIT("data instance") | isNewTyCon tycon = ptext SLIT("newtype instance") | isSynTyCon tycon = ptext SLIT("type instance") @@ -188,52 +193,6 @@ extendFamInstEnv inst_env ins_item@(FamInst {fi_fam = cls_nm, fi_tcs = mb_tcs}) %* * %************************************************************************ -@lookupFamInstEnvExact@ looks up in a @FamInstEnv@ using an exact match. -This is used when we want the @TyCon@ of a particular family instance (e.g., -during deriving classes). - -\begin{code} -{- NOT NEEDED ANY MORE -lookupFamInstEnvExact :: (FamInstEnv -- External package inst-env - ,FamInstEnv) -- Home-package inst-env - -> TyCon -> [Type] -- What we are looking for - -> Maybe FamInst -lookupFamInstEnvExact (pkg_ie, home_ie) fam tys - = home_matches `mplus` pkg_matches - where - rough_tcs = roughMatchTcs tys - all_tvs = all isNothing rough_tcs - home_matches = lookup home_ie - pkg_matches = lookup pkg_ie - - -------------- - lookup env = case lookupUFM env fam of - Nothing -> Nothing -- No instances for this class - Just (FamIE insts has_tv_insts) - -- Short cut for common case: - -- The thing we are looking up is of form (C a - -- b c), and the FamIE has no instances of - -- that form, so don't bother to search - | all_tvs && not has_tv_insts -> Nothing - | otherwise -> find insts - - -------------- - find [] = Nothing - find (item@(FamInst { fi_tcs = mb_tcs, fi_tys = tpl_tys }) : rest) - -- Fast check for no match, uses the "rough match" fields - | instanceCantMatch rough_tcs mb_tcs - = find rest - - -- Proper check - | tcEqTypes tpl_tys tys - = Just item - - -- No match => try next - | otherwise - = find rest --} -\end{code} - @lookupFamInstEnv@ looks up in a @FamInstEnv@, using a one-way match. Multiple matches are only possible in case of type families (not data families), and then, it doesn't matter which match we choose (as the