%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+% (c) The AQUA Project, Glasgow University, 1996
%
-\section[TcTyDecls]{Typecheck algebraic datatypes and type synonyms}
+\section[TcTyDecls]{Typecheck type declarations}
\begin{code}
#include "HsVersions.h"
-module TcTyDecls ( tcTyDecls ) where
-
-import TcMonad -- typechecking monad machinery
-import AbsSyn -- the stuff being typechecked
+module TcTyDecls (
+ tcTyDecl,
+ tcConDecl,
+ tcRecordSelectors
+ ) where
+
+import Ubiq{-uitous-}
+
+import HsSyn ( TyDecl(..), ConDecl(..), BangType(..), HsExpr(..),
+ Match(..), GRHSsAndBinds(..), GRHS(..), OutPat(..),
+ HsBinds(..), HsLit, Stmt, Qual, ArithSeqInfo, PolyType,
+ Bind(..), MonoBinds(..), Sig,
+ MonoType )
+import RnHsSyn ( RenamedTyDecl(..), RenamedConDecl(..) )
+import TcHsSyn ( TcHsBinds(..), TcIdOcc(..), mkHsTyLam )
+
+import TcMonoType ( tcMonoTypeKind, tcMonoType, tcContext )
+import TcType ( tcInstTyVars, tcInstType )
+import TcEnv ( tcLookupTyCon, tcLookupTyVar, tcLookupClass,
+ newLocalId
+ )
+import TcMonad
+import TcKind ( TcKind, unifyKind, mkTcArrowKind, mkTcTypeKind )
-import AbsUniType ( applyTyCon, mkDataTyCon, mkSynonymTyCon,
- getUniDataTyCon, isUnboxedDataType,
- isTyVarTemplateTy, cmpUniTypeMaybeList,
- pprMaybeTy
+import Id ( mkDataCon, dataConSig, mkRecordSelectorId,
+ dataConFieldLabels, StrictnessMark(..)
)
-import CE ( lookupCE, CE(..) )
-import CmdLineOpts ( GlobalSwitch(..) )
-import E ( getE_TCE, getE_CE, plusGVE, nullGVE, GVE(..), E )
-import ErrUtils ( addShortErrLocLine )
-import Errors ( confusedNameErr, specDataNoSpecErr, specDataUnboxedErr )
-import FiniteMap ( FiniteMap, emptyFM, plusFM, singletonFM )
-import IdInfo ( SpecEnv, mkSpecEnv, SpecInfo(..) )
+import FieldLabel
+import Kind ( Kind, mkArrowKind, mkBoxedTypeKind )
+import SpecEnv ( SpecEnv(..), nullSpecEnv )
+import Name ( getNameFullName, Name(..) )
import Pretty
-import SpecTyFuns ( specialiseConstrTys )
-import TCE -- ( nullTCE, unitTCE, lookupTCE, plusTCE, TCE(..), UniqFM )
-import TVE ( mkTVE, TVE(..) )
-import TcConDecls ( tcConDecls )
-import TcMonoType ( tcMonoType )
-import TcPragmas ( tcDataPragmas, tcTypePragmas )
-import Util
+import TyCon ( TyCon, NewOrData(..), mkSynTyCon, mkDataTyCon, tyConDataCons )
+import Type ( getTypeKind, getTyVar, tyVarsOfTypes, eqTy, applyTyCon,
+ mkForAllTys, mkFunTy )
+import TyVar ( getTyVarKind, elementOfTyVarSet )
+import UniqSet ( emptyUniqSet, mkUniqSet, uniqSetToList, unionManyUniqSets, UniqSet(..) )
+import Util ( panic, equivClasses )
\end{code}
-We consult the @CE@/@TCE@ arguments {\em only} to build knots!
+\begin{code}
+tcTyDecl :: RenamedTyDecl -> TcM s TyCon
+\end{code}
-The resulting @TCE@ has info about the type constructors in it; the
-@GVE@ has info about their data constructors.
+Type synonym decls
+~~~~~~~~~~~~~~~~~~
\begin{code}
-tcTyDecls :: E
- -> (Name -> Bool) -- given Name, is it an abstract synonym?
- -> (Name -> [RenamedDataTypeSig]) -- given Name, get specialisation pragmas
- -> [RenamedTyDecl]
- -> Baby_TcM (TCE, GVE,
- FiniteMap TyCon [[Maybe UniType]])
- -- specialisations:
- -- local data types: requsted by source pragmas
- -- imported data types: from interface file
-
-tcTyDecls e _ _ [] = returnB_Tc (nullTCE, nullGVE, emptyFM)
-
-tcTyDecls e is_abs_syn get_spec_sigs (tyd: tyds)
- = tc_decl tyd `thenB_Tc` \ (tce1, gve1, specs1) ->
- tcTyDecls e is_abs_syn get_spec_sigs tyds
- `thenB_Tc` \ (tce2, gve2, specs2) ->
+tcTyDecl (TySynonym tycon_name tyvar_names rhs src_loc)
+ = tcAddSrcLoc src_loc $
+ tcAddErrCtxt (tySynCtxt tycon_name) $
+
+ -- Look up the pieces
+ tcLookupTyCon tycon_name `thenNF_Tc` \ (tycon_kind, _, rec_tycon) ->
+ mapAndUnzipNF_Tc tcLookupTyVar tyvar_names `thenNF_Tc` \ (tyvar_kinds, rec_tyvars) ->
+
+ -- Look at the rhs
+ tcMonoTypeKind rhs `thenTc` \ (rhs_kind, rhs_ty) ->
+
+ -- Unify tycon kind with (k1->...->kn->rhs)
+ unifyKind tycon_kind
+ (foldr mkTcArrowKind rhs_kind tyvar_kinds)
+ `thenTc_`
let
- tce3 = tce1 `plusTCE` tce2
- gve3 = gve1 `plusGVE` gve2
- specs3 = specs1 `plusFM` specs2
+ -- Getting the TyCon's kind is a bit of a nuisance. We can't use the tycon_kind,
+ -- because that's a TcKind and may not yet be fully unified with other kinds.
+ -- We could have augmented the tycon environment with a knot-tied kind,
+ -- but the simplest thing to do seems to be to get the Kind by (lazily)
+ -- looking at the tyvars and rhs_ty.
+ result_kind, final_tycon_kind :: Kind -- NB not TcKind!
+ result_kind = getTypeKind rhs_ty
+ final_tycon_kind = foldr (mkArrowKind . getTyVarKind) result_kind rec_tyvars
+
+ -- Construct the tycon
+ tycon = mkSynTyCon (getItsUnique tycon_name)
+ (getNameFullName tycon_name)
+ final_tycon_kind
+ (length tyvar_names)
+ rec_tyvars
+ rhs_ty
in
- returnB_Tc (tce3, gve3, specs3)
- where
- rec_ce = getE_CE e
- rec_tce = getE_TCE e
-
- -- continued...
+ returnTc tycon
\end{code}
-We don't need to substitute here, because the @TCE@s
-(which are at the top level) cannot contain free type variables.
+Algebraic data and newtype decls
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Gather relevant info:
\begin{code}
- tc_decl (TyData context name@(PreludeTyCon uniq full_name arity True{-"data"-})
- tyvars con_decls derivings pragmas src_loc)
- -- ToDo: context
- = tc_data_decl uniq name full_name arity tyvars con_decls
- derivings pragmas src_loc
-
- tc_decl (TyData context name@(OtherTyCon uniq full_name arity True{-"data"-} _)
- tyvars con_decls derivings pragmas src_loc)
- -- ToDo: context
- = tc_data_decl uniq name full_name arity tyvars con_decls
- derivings pragmas src_loc
-
- tc_decl (TyData _ bad_name _ _ _ _ src_loc)
- = failB_Tc (confusedNameErr "Bad name on a datatype constructor (a Prelude name?)"
- bad_name src_loc)
-
- tc_decl (TySynonym name@(PreludeTyCon uniq full_name arity False{-"type"-})
- tyvars mono_ty pragmas src_loc)
- = tc_syn_decl uniq name full_name arity tyvars mono_ty pragmas src_loc
-
- tc_decl (TySynonym name@(OtherTyCon uniq full_name arity False{-"type"-} _)
- tyvars mono_ty pragmas src_loc)
- = tc_syn_decl uniq name full_name arity tyvars mono_ty pragmas src_loc
-
- tc_decl (TySynonym bad_name _ _ _ src_loc)
- = failB_Tc (confusedNameErr "Bad name on a type-synonym constructor (a Prelude name?)"
- bad_name src_loc)
-\end{code}
+tcTyDecl (TyData context tycon_name tyvar_names con_decls derivings pragmas src_loc)
+ = tcTyDataOrNew DataType context tycon_name tyvar_names con_decls derivings pragmas src_loc
-Real work for @data@ declarations:
-\begin{code}
- tc_data_decl uniq name full_name arity tyvars con_decls derivings pragmas src_loc
- = addSrcLocB_Tc src_loc (
- let
- (tve, new_tyvars, _) = mkTVE tyvars
- rec_tycon = lookupTCE rec_tce name
- -- We know the lookup will succeed, because we are just
- -- about to put it in the outgoing TCE!
-
- spec_sigs = get_spec_sigs name
- in
- tcSpecDataSigs rec_tce spec_sigs [] `thenB_Tc` \ user_spec_infos ->
-
- recoverIgnoreErrorsB_Tc ([], []) (
- tcDataPragmas rec_tce tve rec_tycon new_tyvars pragmas
- ) `thenB_Tc` \ (pragma_con_decls, pragma_spec_infos) ->
- let
- (condecls_to_use, ignore_condecl_errors_if_pragma)
- = if null pragma_con_decls then
- (con_decls, id)
- else
- if null con_decls
- then (pragma_con_decls, recoverIgnoreErrorsB_Tc nullGVE)
- else panic "tcTyDecls:data: user and pragma condecls!"
-
- specinfos_to_use
- = if null pragma_spec_infos then
- user_spec_infos
- else
- if null user_spec_infos
- then pragma_spec_infos
- else panic "tcTyDecls:data: user and pragma specinfos!"
-
- specenv_to_use = mkSpecEnv specinfos_to_use
- in
- ignore_condecl_errors_if_pragma
- (tcConDecls rec_tce tve rec_tycon new_tyvars specenv_to_use condecls_to_use)
- `thenB_Tc` \ gve ->
- let
- condecls = map snd gve
-
- derived_classes = map (lookupCE rec_ce) derivings
-
- new_tycon
- = mkDataTyCon uniq
- full_name arity new_tyvars condecls
+tcTyDecl (TyNew context tycon_name tyvar_names con_decl derivings pragmas src_loc)
+ = tcTyDataOrNew NewType context tycon_name tyvar_names con_decl derivings pragmas src_loc
+
+
+tcTyDataOrNew data_or_new context tycon_name tyvar_names con_decls derivings pragmas src_loc
+ = tcAddSrcLoc src_loc $
+ tcAddErrCtxt (tyDataCtxt tycon_name) $
+
+ -- Lookup the pieces
+ tcLookupTyCon tycon_name `thenNF_Tc` \ (tycon_kind, _, rec_tycon) ->
+ mapAndUnzipNF_Tc tcLookupTyVar tyvar_names `thenNF_Tc` \ (tyvar_kinds, rec_tyvars) ->
+ tc_derivs derivings `thenNF_Tc` \ derived_classes ->
+
+ -- Typecheck the context
+ tcContext context `thenTc` \ ctxt ->
+
+ -- Unify tycon kind with (k1->...->kn->Type)
+ unifyKind tycon_kind
+ (foldr mkTcArrowKind mkTcTypeKind tyvar_kinds)
+ `thenTc_`
+
+ -- Walk the condecls
+ mapTc (tcConDecl rec_tycon rec_tyvars ctxt) con_decls
+ `thenTc` \ con_ids ->
+ let
+ -- Construct the tycon
+ final_tycon_kind :: Kind -- NB not TcKind!
+ final_tycon_kind = foldr (mkArrowKind . getTyVarKind) mkBoxedTypeKind rec_tyvars
+
+ tycon = mkDataTyCon (getItsUnique tycon_name)
+ final_tycon_kind
+ (getNameFullName tycon_name)
+ rec_tyvars
+ ctxt
+ con_ids
derived_classes
- (null pragma_con_decls)
- -- if constrs are from pragma we are *abstract*
-
- spec_list
- = map (\ (SpecInfo maybe_tys _ _) -> maybe_tys) specinfos_to_use
-
- spec_map
- = if null spec_list then
- emptyFM
- else
- singletonFM rec_tycon spec_list
- in
- returnB_Tc (unitTCE uniq new_tycon, gve, spec_map)
- -- It's OK to return pragma condecls in gve, even
- -- though some of those names should be "invisible",
- -- because the *renamer* is supposed to have dealt with
- -- naming/scope issues already.
- )
+ data_or_new
+ in
+ returnTc tycon
+
+tc_derivs Nothing = returnNF_Tc []
+tc_derivs (Just ds) = mapNF_Tc tc_deriv ds
+
+tc_deriv name
+ = tcLookupClass name `thenNF_Tc` \ (_, clas) ->
+ returnNF_Tc clas
\end{code}
-Real work for @type@ (synonym) declarations:
+Generating selector bindings for record delarations
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
\begin{code}
- tc_syn_decl uniq name full_name arity tyvars mono_ty pragmas src_loc
- = addSrcLocB_Tc src_loc (
-
- let (tve, new_tyvars, _) = mkTVE tyvars
- in
- tcMonoType rec_ce rec_tce tve mono_ty `thenB_Tc` \ expansion ->
- let
- -- abstractness info either comes from the interface pragmas
- -- (tcTypePragmas) or from a user-pragma in this module
- -- (is_abs_syn)
- abstract = tcTypePragmas pragmas
- || is_abs_syn name
-
- new_tycon = mkSynonymTyCon uniq full_name
- arity new_tyvars expansion (not abstract)
- in
- returnB_Tc (unitTCE uniq new_tycon, nullGVE, emptyFM)
- )
+tcRecordSelectors :: TyCon -> TcM s ([Id], TcHsBinds s)
+tcRecordSelectors tycon
+ = mapAndUnzipTc (tcRecordSelector tycon) groups `thenTc` \ (ids, binds) ->
+ returnTc (ids, SingleBind (NonRecBind (foldr AndMonoBinds EmptyMonoBinds binds)))
+ where
+ data_cons = tyConDataCons tycon
+ fields = [ (con, field) | con <- data_cons,
+ field <- dataConFieldLabels con
+ ]
+
+ -- groups is list of fields that share a common name
+ groups = equivClasses cmp_name fields
+ cmp_name (_, field1) (_, field2)
+ = fieldLabelName field1 `cmp` fieldLabelName field2
\end{code}
-%************************************************************************
-%* *
-\subsection{Specialisation Signatures for Data Type declarations}
-%* *
-%************************************************************************
+We're going to build a record selector that looks like this:
+
+ data T a b c = T1 { op :: a, ...}
+ | T2 { op :: a, ...}
+ | T3
+
+ sel :: forall a b c. T a b c -> a
+ sel = /\ a b c -> \ T1 { sel = x } -> x
+ T2 { sel = 2 } -> x
-@tcSpecDataSigs@ checks data type specialisation signatures for
-validity, and returns the list of specialisation requests.
+Note that the selector Id itself is used as the field
+label; it has to be an Id, you see!
\begin{code}
-tcSpecDataSigs :: TCE
- -> [RenamedDataTypeSig]
- -> [(RenamedDataTypeSig,SpecInfo)]
- -> Baby_TcM [SpecInfo]
-
-tcSpecDataSigs tce (s:ss) accum
- = tc_sig s `thenB_Tc` \ info ->
- tcSpecDataSigs tce ss ((s,info):accum)
- where
- tc_sig (SpecDataSig n ty src_loc)
- = addSrcLocB_Tc src_loc (
- let
- ty_names = extractMonoTyNames (==) ty
- (tve,_,_) = mkTVE ty_names
- fake_CE = panic "tcSpecDataSigs:CE"
- in
- -- Typecheck specialising type (includes arity check)
- tcMonoType fake_CE tce tve ty `thenB_Tc` \ tau_ty ->
- let
- (_,ty_args,_) = getUniDataTyCon tau_ty
- is_unboxed_or_tyvar ty = isUnboxedDataType ty || isTyVarTemplateTy ty
- in
- -- Check at least one unboxed type in specialisation
- checkB_Tc (not (any isUnboxedDataType ty_args))
- (specDataNoSpecErr n ty_args src_loc) `thenB_Tc_`
-
- -- Check all types are unboxed or tyvars
- -- (specific boxed types are redundant)
- checkB_Tc (not (all is_unboxed_or_tyvar ty_args))
- (specDataUnboxedErr n ty_args src_loc) `thenB_Tc_`
-
- let
- maybe_tys = specialiseConstrTys ty_args
- in
- returnB_Tc (SpecInfo maybe_tys 0 (panic "SpecData:SpecInfo:SpecId"))
- )
-
-tcSpecDataSigs tce [] accum
- = -- Remove any duplicates from accumulated specinfos
- getSwitchCheckerB_Tc `thenB_Tc` \ sw_chkr ->
+tcRecordSelector tycon fields@((first_con, first_field_label) : other_fields)
+ = panic "tcRecordSelector: don't typecheck"
+{-
+ = let
+ field_ty = fieldLabelType first_field_label
+ field_name = fieldLabelName first_field_label
+ other_tys = [fieldLabelType fl | (_, fl) <- fields]
+ (tyvars, _, _, _) = dataConSig first_con
+ -- tyvars of first_con may be free in first_ty
+ in
+
+ -- Check that all the fields in the group have the same type
+ -- This check assumes that all the constructors of a given
+ -- data type use the same type variables
+ checkTc (all (eqTy field_ty) other_tys)
+ (fieldTypeMisMatch field_name) `thenTc_`
- (if sw_chkr SpecialiseTrace && not (null duplicates) then
- pprTrace "Duplicate SPECIALIZE data pragmas:\n"
- (ppAboves (map specmsg sep_dups))
- else id)(
+ -- Create an Id for the field itself
+ tcInstTyVars tyvars `thenNF_Tc` \ (tyvars', tyvar_tys, tenv) ->
+ tcInstType tenv field_ty `thenNF_Tc` \ field_ty' ->
+ let
+ data_ty' = applyTyCon tycon tyvar_tys
+ in
+ newLocalId SLIT("x") field_ty' `thenNF_Tc` \ field_id ->
+ newLocalId SLIT("r") data_ty' `thenNF_Tc` \ record_id ->
- (if sw_chkr SpecialiseTrace && not (null spec_infos) then
- pprTrace "Specialising "
- (ppHang (ppCat [ppr PprDebug name, ppStr "at types:"])
- 4 (ppAboves (map pp_spec spec_infos)))
+ -- Now build the selector
+ let
+ tycon_src_loc = getSrcLoc tycon
+
+ selector_ty = mkForAllTys tyvars' $
+ mkFunTy data_ty' $
+ field_ty'
+
+ selector_id = mkRecordSelectorId first_field_label selector_ty
+
+ -- HsSyn is dreadfully verbose for defining the selector!
+ selector_rhs = mkHsTyLam tyvars' $
+ HsLam $
+ PatMatch (VarPat record_id) $
+ GRHSMatch $
+ GRHSsAndBindsOut [OtherwiseGRHS selector_body tycon_src_loc]
+ EmptyBinds field_ty'
+
+ selector_body = HsCase (HsVar record_id) (map mk_match fields) tycon_src_loc
+
+ mk_match (con_id, field_label)
+ = PatMatch (RecPat con_id data_ty' [(selector_id, VarPat field_id, False)]) $
+ GRHSMatch $
+ GRHSsAndBindsOut [OtherwiseGRHS (HsVar field_id)
+ (getSrcLoc (fieldLabelName field_label))]
+ EmptyBinds
+ field_ty'
+ in
+ returnTc (selector_id, VarMonoBind selector_id selector_rhs)
+-}
+\end{code}
- else id) (
+Constructors
+~~~~~~~~~~~~
+\begin{code}
+tcConDecl :: TyCon -> [TyVar] -> [(Class,Type)] -> RenamedConDecl -> TcM s Id
+
+tcConDecl tycon tyvars ctxt (ConDecl name btys src_loc)
+ = tcDataCon tycon tyvars ctxt name btys src_loc
+
+tcConDecl tycon tyvars ctxt (ConOpDecl bty1 op bty2 src_loc)
+ = tcDataCon tycon tyvars ctxt op [bty1,bty2] src_loc
+
+tcConDecl tycon tyvars ctxt (NewConDecl name ty src_loc)
+ = tcAddSrcLoc src_loc $
+ tcMonoType ty `thenTc` \ arg_ty ->
+ let
+ data_con = mkDataCon (getItsUnique name)
+ (getNameFullName name)
+ [NotMarkedStrict]
+ [{- No labelled fields -}]
+ tyvars
+ ctxt
+ [arg_ty]
+ tycon
+ -- nullSpecEnv
+ in
+ returnTc data_con
- returnB_Tc (spec_infos)
- ))
+tcConDecl tycon tyvars ctxt (RecConDecl name fields src_loc)
+ = tcAddSrcLoc src_loc $
+ mapTc tcField fields `thenTc` \ field_label_infos_s ->
+ let
+ field_label_infos = concat field_label_infos_s
+ stricts = [strict | (_, _, strict) <- field_label_infos]
+ arg_tys = [ty | (_, ty, _) <- field_label_infos]
+
+ field_labels = [ mkFieldLabel name ty tag
+ | ((name, ty, _), tag) <- field_label_infos `zip` allFieldLabelTags
+ ]
+
+ data_con = mkDataCon (getItsUnique name)
+ (getNameFullName name)
+ stricts
+ field_labels
+ tyvars
+ (thinContext arg_tys ctxt)
+ arg_tys
+ tycon
+ -- nullSpecEnv
+ in
+ returnTc data_con
+
+tcField (field_label_names, bty)
+ = tcMonoType (get_ty bty) `thenTc` \ field_ty ->
+ returnTc [(name, field_ty, get_strictness bty) | name <- field_label_names]
+
+tcDataCon tycon tyvars ctxt name btys src_loc
+ = tcAddSrcLoc src_loc $
+ let
+ stricts = map get_strictness btys
+ tys = map get_ty btys
+ in
+ mapTc tcMonoType tys `thenTc` \ arg_tys ->
+ let
+ data_con = mkDataCon (getItsUnique name)
+ (getNameFullName name)
+ stricts
+ [{- No field labels -}]
+ tyvars
+ (thinContext arg_tys ctxt)
+ arg_tys
+ tycon
+ -- nullSpecEnv
+ in
+ returnTc data_con
+
+-- The context for a data constructor should be limited to
+-- the type variables mentioned in the arg_tys
+thinContext arg_tys ctxt
+ = filter in_arg_tys ctxt
where
- spec_infos = map (snd . head) equiv
+ arg_tyvars = tyVarsOfTypes arg_tys
+ in_arg_tys (clas,ty) = getTyVar "tcDataCon" ty `elementOfTyVarSet` arg_tyvars
+
+get_strictness (Banged ty) = MarkedStrict
+get_strictness (Unbanged ty) = NotMarkedStrict
+
+get_ty (Banged ty) = ty
+get_ty (Unbanged ty) = ty
+\end{code}
+
- equiv = equivClasses cmp_info accum
- duplicates = filter (not . singleton) equiv
- cmp_info (_, SpecInfo tys1 _ _) (_, SpecInfo tys2 _ _)
- = cmpUniTypeMaybeList tys1 tys2
+Errors and contexts
+~~~~~~~~~~~~~~~~~~~
+\begin{code}
+tySynCtxt tycon_name sty
+ = ppCat [ppStr "In the type declaration for", ppr sty tycon_name]
- singleton [_] = True
- singleton _ = False
+tyDataCtxt tycon_name sty
+ = ppCat [ppStr "In the data declaration for", ppr sty tycon_name]
- sep_dups = tail (concat (map ((:) Nothing . map Just) duplicates))
- specmsg (Just (SpecDataSig _ ty locn, _))
- = addShortErrLocLine locn ( \ sty -> ppr sty ty ) PprDebug
- specmsg Nothing
- = ppStr "***"
+tyNewCtxt tycon_name sty
+ = ppCat [ppStr "In the newtype declaration for", ppr sty tycon_name]
- ((SpecDataSig name _ _, _):_) = accum
- pp_spec (SpecInfo tys _ _) = ppInterleave ppNil [pprMaybeTy PprDebug ty | ty <- tys]
+fieldTypeMisMatch field_name sty
+ = ppSep [ppStr "Declared types differ for field", ppr sty field_name]
\end{code}
projects / ghc-hetmet.git / blobdiff