\begin{code}
module FamInstEnv (
- FamInst(..), famInstTyCon, pprFamInst, pprFamInstHdr, pprFamInsts,
+ FamInst(..), famInstTyCon, famInstTyVars,
+ pprFamInst, pprFamInstHdr, pprFamInsts,
famInstHead, mkLocalFamInst, mkImportedFamInst,
- FamInstEnv, emptyFamInstEnv, extendFamInstEnv, extendFamInstEnvList,
+ FamInstEnvs, FamInstEnv, emptyFamInstEnv,
+ extendFamInstEnv, extendFamInstEnvList,
famInstEnvElts, familyInstances,
lookupFamInstEnv, lookupFamInstEnvUnify
import Outputable
import Maybe
-import Monad
\end{code}
\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 fi_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
}
--
famInstTyCon :: FamInst -> TyCon
famInstTyCon = fi_tycon
+
+famInstTyVars = fi_tvs
\end{code}
\begin{code}
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")
\begin{code}
type FamInstEnv = UniqFM FamilyInstEnv -- Maps a family to its instances
+type FamInstEnvs = (FamInstEnv, FamInstEnv)
+ -- External package inst-env, Home-package inst-env
+
data FamilyInstEnv
= FamIE [FamInst] -- The instances for a particular family, in any order
Bool -- True <=> there is an instance of form T a b c
add (FamIE items tyvar) _ = FamIE (ins_item:items)
(ins_tyvar || tyvar)
ins_tyvar = not (any isJust mb_tcs)
-\end{code}
+\end{code}
%************************************************************************
%* *
instances are guaranteed confluent).
\begin{code}
-lookupFamInstEnv :: (FamInstEnv -- External package inst-env
- ,FamInstEnv) -- Home-package inst-env
+lookupFamInstEnv :: FamInstEnvs
-> TyCon -> [Type] -- What we are looking for
-> [(TvSubst, FamInst)] -- Successful matches
lookupFamInstEnv (pkg_ie, home_ie) fam tys