From ac9c1e5de9629103a125e0515dcee2466ff898a7 Mon Sep 17 00:00:00 2001 From: Manuel M T Chakravarty Date: Mon, 18 Sep 2006 22:55:51 +0000 Subject: [PATCH] Use family and instance keyword to identify indexed types Tue Aug 15 20:16:00 EDT 2006 Manuel M T Chakravarty * Use family and instance keyword to identify indexed types --- compiler/parser/Lexer.x | 3 + compiler/parser/Parser.y.pp | 129 ++++++++++++++++++++++++------------------ compiler/parser/RdrHsSyn.lhs | 36 ++++++------ 3 files changed, 94 insertions(+), 74 deletions(-) diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x index aed9cfb..fdbaeef 100644 --- a/compiler/parser/Lexer.x +++ b/compiler/parser/Lexer.x @@ -377,6 +377,7 @@ data Token | ITdotnet | ITmdo | ITiso + | ITfamily -- Pragmas | ITinline_prag Bool -- True <=> INLINE, False <=> NOINLINE @@ -501,6 +502,7 @@ isSpecial ITccallconv = True isSpecial ITstdcallconv = True isSpecial ITmdo = True isSpecial ITiso = True +isSpecial ITfamily = True isSpecial _ = False -- the bitmap provided as the third component indicates whether the @@ -542,6 +544,7 @@ reservedWordsFM = listToUFM $ ( "forall", ITforall, bit tvBit), ( "mdo", ITmdo, bit glaExtsBit), ( "iso", ITiso, bit glaExtsBit), + ( "family", ITfamily, bit glaExtsBit), ( "foreign", ITforeign, bit ffiBit), ( "export", ITexport, bit ffiBit), diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp index dc86c00..0a8b0b6 100644 --- a/compiler/parser/Parser.y.pp +++ b/compiler/parser/Parser.y.pp @@ -186,6 +186,7 @@ incorrect. 'unsafe' { L _ ITunsafe } 'mdo' { L _ ITmdo } 'iso' { L _ ITiso } + 'family' { L _ ITfamily } 'stdcall' { L _ ITstdcallconv } 'ccall' { L _ ITccallconv } 'dotnet' { L _ ITdotnet } @@ -468,7 +469,7 @@ cl_decl :: { LTyClDecl RdrName } {% do { let { (binds, sigs, ats) = cvBindsAndSigs (unLoc $4) ; (ctxt, tc, tvs, tparms) = unLoc $2} - ; checkTyVars tparms False -- only type vars allowed + ; checkTyVars tparms -- only type vars allowed ; checkKindSigs ats ; return $ L (comb4 $1 $2 $3 $4) (mkClassDecl (ctxt, tc, tvs) @@ -477,79 +478,97 @@ cl_decl :: { LTyClDecl RdrName } -- Type declarations -- ty_decl :: { LTyClDecl RdrName } - -- type function signature and equations (w/ type synonyms as special - -- case); we need to handle all this in one rule to avoid a large - -- number of shift/reduce conflicts - : 'type' opt_iso type kind_or_ctype + -- ordinary type synonyms + : 'type' type '=' ctype + -- Note ctype, not sigtype, on the right of '=' + -- We allow an explicit for-all but we don't insert one + -- in type Foo a = (b,b) + -- Instead we just say b is out of scope -- -- Note the use of type for the head; this allows - -- infix type constructors to be declared and type - -- patterns for type function equations - -- - -- We have that `typats :: Maybe [LHsType name]' is `Nothing' - -- (in the second case alternative) when all arguments are - -- variables (and we thus have a vanilla type synonym - -- declaration); otherwise, it contains all arguments as type - -- patterns. + -- infix type constructors to be declared + {% do { (tc, tvs, _) <- checkSynHdr $2 False + ; return (L (comb2 $1 $4) + (TySynonym tc tvs Nothing $4)) + } } + + -- type family declarations + | 'type' 'family' opt_iso type '::' kind + -- Note the use of type for the head; this allows + -- infix type constructors to be declared -- - {% case $4 of - Left kind -> - do { (tc, tvs, _) <- checkSynHdr $3 False - ; return (L (comb3 $1 $3 kind) - (TyFunction tc tvs $2 (unLoc kind))) - } - Right ty | not $2 -> - do { (tc, tvs, typats) <- checkSynHdr $3 True - ; return (L (comb2 $1 ty) - (TySynonym tc tvs typats ty)) } - Right ty | otherwise -> - parseError (comb2 $1 ty) - "iso tag is only allowed in kind signatures" - } - - -- kind signature of indexed type - | data_or_newtype tycl_hdr '::' kind - {% do { let {(ctxt, tc, tvs, tparms) = unLoc $2} - ; checkTyVars tparms False -- no type pattern - ; return $ - L (comb3 $1 $2 $4) - (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) - (Just (unLoc $4)) [] Nothing) } } + {% do { (tc, tvs, _) <- checkSynHdr $4 False + ; return (L (comb3 $1 $4 $6) + (TyFunction tc tvs $3 (unLoc $6))) + } } + + -- type instance declarations + | 'type' 'instance' type '=' ctype + -- Note the use of type for the head; this allows + -- infix type constructors and type patterns + -- + {% do { (tc, tvs, typats) <- checkSynHdr $3 True + ; return (L (comb2 $1 $5) + (TySynonym tc tvs (Just typats) $5)) + } } - -- data type or newtype declaration + -- ordinary data type or newtype declaration | data_or_newtype tycl_hdr constrs deriving {% do { let {(ctxt, tc, tvs, tparms) = unLoc $2} - ; tpats <- checkTyVars tparms True -- can have type pats + ; checkTyVars tparms -- no type pattern ; return $ L (comb4 $1 $2 $3 $4) -- We need the location on tycl_hdr in case -- constrs and deriving are both empty - (mkTyData (unLoc $1) (ctxt, tc, tvs, tpats) - Nothing (reverse (unLoc $3)) (unLoc $4)) } } + (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) + Nothing (reverse (unLoc $3)) (unLoc $4)) } } - -- GADT declaration + -- ordinary GADT declaration | data_or_newtype tycl_hdr opt_kind_sig 'where' gadt_constrlist deriving {% do { let {(ctxt, tc, tvs, tparms) = unLoc $2} - ; tpats <- checkTyVars tparms True -- can have type pats + ; checkTyVars tparms -- can have type pats ; return $ L (comb4 $1 $2 $4 $5) - (mkTyData (unLoc $1) (ctxt, tc, tvs, tpats) $3 - (reverse (unLoc $5)) (unLoc $6)) } } + (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) $3 + (reverse (unLoc $5)) (unLoc $6)) } } + + -- data/newtype family + | data_or_newtype 'family' tycl_hdr '::' kind + {% do { let {(ctxt, tc, tvs, tparms) = unLoc $3} + ; checkTyVars tparms -- no type pattern + ; return $ + L (comb3 $1 $2 $5) + (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) + (Just (unLoc $5)) [] Nothing) } } + + -- data/newtype instance declaration + | data_or_newtype 'instance' tycl_hdr constrs deriving + {% do { let {(ctxt, tc, tvs, tparms) = unLoc $3} + -- can have type pats + ; return $ + L (comb4 $1 $3 $4 $5) + -- We need the location on tycl_hdr in case + -- constrs and deriving are both empty + (mkTyData (unLoc $1) (ctxt, tc, tvs, Just tparms) + Nothing (reverse (unLoc $4)) (unLoc $5)) } } + + -- GADT instance declaration + | data_or_newtype 'instance' tycl_hdr opt_kind_sig + 'where' gadt_constrlist + deriving + {% do { let {(ctxt, tc, tvs, tparms) = unLoc $3} + -- can have type pats + ; return $ + L (comb4 $1 $3 $6 $7) + (mkTyData (unLoc $1) (ctxt, tc, tvs, Just tparms) + $4 (reverse (unLoc $6)) (unLoc $7)) } } opt_iso :: { Bool } : { False } | 'iso' { True } -kind_or_ctype :: { Either (Located Kind) (LHsType RdrName) } - : '::' kind { Left (LL (unLoc $2)) } - | '=' ctype { Right (LL (unLoc $2)) } - -- Note ctype, not sigtype, on the right of '=' - -- We allow an explicit for-all but we don't insert one - -- in type Foo a = (b,b) - -- Instead we just say b is out of scope - data_or_newtype :: { Located NewOrData } : 'data' { L1 DataType } | 'newtype' { L1 NewType } @@ -1444,6 +1463,8 @@ varid_no_unsafe :: { Located RdrName } : VARID { L1 $! mkUnqual varName (getVARID $1) } | special_id { L1 $! mkUnqual varName (unLoc $1) } | 'forall' { L1 $! mkUnqual varName FSLIT("forall") } + | 'iso' { L1 $! mkUnqual varName FSLIT("iso") } + | 'family' { L1 $! mkUnqual varName FSLIT("family") } qvarsym :: { Located RdrName } : varsym { $1 } @@ -1467,7 +1488,8 @@ varsym_no_minus :: { Located RdrName } -- varsym not including '-' -- These special_ids are treated as keywords in various places, -- but as ordinary ids elsewhere. 'special_id' collects all these --- except 'unsafe' and 'forall' whose treatment differs depending on context +-- except 'unsafe', 'forall', 'family', and 'iso' whose treatment differs +-- depending on context special_id :: { Located FastString } special_id : 'as' { L1 FSLIT("as") } @@ -1478,7 +1500,6 @@ special_id | 'dynamic' { L1 FSLIT("dynamic") } | 'stdcall' { L1 FSLIT("stdcall") } | 'ccall' { L1 FSLIT("ccall") } - | 'iso' { L1 FSLIT("iso") } special_sym :: { Located FastString } special_sym : '!' { L1 FSLIT("!") } diff --git a/compiler/parser/RdrHsSyn.lhs b/compiler/parser/RdrHsSyn.lhs index b66c759..14ccd27 100644 --- a/compiler/parser/RdrHsSyn.lhs +++ b/compiler/parser/RdrHsSyn.lhs @@ -36,8 +36,8 @@ module RdrHsSyn ( checkContext, -- HsType -> P HsContext checkPred, -- HsType -> P HsPred checkTyClHdr, -- LHsContext RdrName -> LHsType RdrName -> P (LHsContext RdrName, Located RdrName, [LHsTyVarBndr RdrName], [LHsType RdrName]) - checkTyVars, -- [LHsType RdrName] -> Bool -> P () - checkSynHdr, -- LHsType RdrName -> P (Located RdrName, [LHsTyVarBndr RdrName], Maybe [LHsType RdrName]) + checkTyVars, -- [LHsType RdrName] -> P () + checkSynHdr, -- LHsType RdrName -> P (Located RdrName, [LHsTyVarBndr RdrName], [LHsType RdrName]) checkKindSigs, -- [LTyClDecl RdrName] -> P () checkInstType, -- HsType -> P HsType checkPattern, -- HsExp -> P HsPat @@ -70,6 +70,7 @@ import FastString import Panic import List ( isSuffixOf, nubBy ) +import Monad ( unless ) \end{code} @@ -378,25 +379,20 @@ checkInstType (L l t) return (L l (HsForAllTy Implicit [] (noLoc []) dict_ty)) -- Check whether the given list of type parameters are all type variables --- (possibly with a kind signature). If the second argument is `False', we +-- (possibly with a kind signature). If the second argument is `False', -- only type variables are allowed and we raise an error on encountering a --- non-variable; otherwise, we return the entire list parameters iff at least --- one is not a variable. +-- non-variable; otherwise, we allow non-variable arguments and return the +-- entire list of parameters. -- -checkTyVars :: [LHsType RdrName] -> Bool -> P (Maybe [LHsType RdrName]) -checkTyVars tparms nonVarsOk = - do - areVars <- mapM chk tparms - return $ if and areVars then Nothing else Just tparms +checkTyVars :: [LHsType RdrName] -> P () +checkTyVars tparms = mapM_ chk tparms where -- Check that the name space is correct! chk (L l (HsKindSig (L _ (HsTyVar tv)) k)) - | isRdrTyVar tv = return True + | isRdrTyVar tv = return () chk (L l (HsTyVar tv)) - | isRdrTyVar tv = return True - chk (L l other) - | nonVarsOk = return False - | otherwise = + | isRdrTyVar tv = return () + chk (L l other) = parseError l "Type found where type variable expected" -- Check whether the type arguments in a type synonym head are simply @@ -405,14 +401,14 @@ checkTyVars tparms nonVarsOk = -- indicate a vanilla type synonym. -- checkSynHdr :: LHsType RdrName - -> Bool -- non-variables admitted? + -> Bool -- is type instance? -> P (Located RdrName, -- head symbol [LHsTyVarBndr RdrName], -- parameters - Maybe [LHsType RdrName]) -- type patterns -checkSynHdr ty nonVarsOk = + [LHsType RdrName]) -- type patterns +checkSynHdr ty isTyInst = do { (_, tc, tvs, tparms) <- checkTyClHdr (noLoc []) ty - ; typats <- checkTyVars tparms nonVarsOk - ; return (tc, tvs, typats) } + ; unless isTyInst $ checkTyVars tparms + ; return (tc, tvs, tparms) } -- Well-formedness check and decomposition of type and class heads. -- 1.7.10.4