2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 \section[HsBinds]{Abstract syntax: top-level bindings and signatures}
7 Datatype for: @BindGroup@, @Bind@, @Sig@, @Bind@.
10 {-# OPTIONS -fno-warn-incomplete-patterns #-}
11 -- The above warning supression flag is a temporary kludge.
12 -- While working on this module you are encouraged to remove it and fix
13 -- any warnings in the module. See
14 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
16 {-# LANGUAGE DeriveDataTypeable #-}
20 import {-# SOURCE #-} HsExpr ( pprExpr, LHsExpr,
21 MatchGroup, pprFunBind,
23 import {-# SOURCE #-} HsPat ( LPat )
41 import Data.IORef( IORef )
42 import Data.Data hiding ( Fixity )
45 %************************************************************************
47 \subsection{Bindings: @BindGroup@}
49 %************************************************************************
51 Global bindings (where clauses)
54 -- During renaming, we need bindings where the left-hand sides
55 -- have been renamed but the the right-hand sides have not.
56 -- the ...LR datatypes are parametrized by two id types,
57 -- one for the left and one for the right.
58 -- Other than during renaming, these will be the same.
60 type HsLocalBinds id = HsLocalBindsLR id id
62 data HsLocalBindsLR idL idR -- Bindings in a 'let' expression
63 -- or a 'where' clause
64 = HsValBinds (HsValBindsLR idL idR)
65 | HsIPBinds (HsIPBinds idR)
67 deriving (Data, Typeable)
69 type HsValBinds id = HsValBindsLR id id
71 data HsValBindsLR idL idR -- Value bindings (not implicit parameters)
72 = ValBindsIn -- Before renaming
73 (LHsBindsLR idL idR) [LSig idR] -- Not dependency analysed
74 -- Recursive by default
76 | ValBindsOut -- After renaming
77 [(RecFlag, LHsBinds idL)] -- Dependency analysed, later bindings
78 -- in the list may depend on earlier
81 deriving (Data, Typeable)
83 type LHsBinds id = Bag (LHsBind id)
84 type LHsBind id = Located (HsBind id)
85 type HsBind id = HsBindLR id id
87 type LHsBindLR idL idR = Located (HsBindLR idL idR)
88 type LHsBindsLR idL idR = Bag (LHsBindLR idL idR)
91 = -- | FunBind is used for both functions @f x = e@
92 -- and variables @f = \x -> e@
94 -- Reason 1: Special case for type inference: see 'TcBinds.tcMonoBinds'.
96 -- Reason 2: Instance decls can only have FunBinds, which is convenient.
97 -- If you change this, you'll need to change e.g. rnMethodBinds
99 -- But note that the form @f :: a->a = ...@
100 -- parses as a pattern binding, just like
101 -- @(f :: a -> a) = ... @
104 fun_id :: Located idL,
106 fun_infix :: Bool, -- ^ True => infix declaration
108 fun_matches :: MatchGroup idR, -- ^ The payload
110 fun_co_fn :: HsWrapper, -- ^ Coercion from the type of the MatchGroup to the type of
113 -- f :: Int -> forall a. a -> a
116 -- Then the MatchGroup will have type (Int -> a' -> a')
117 -- (with a free type variable a'). The coercion will take
118 -- a CoreExpr of this type and convert it to a CoreExpr of
119 -- type Int -> forall a'. a' -> a'
120 -- Notice that the coercion captures the free a'.
122 bind_fvs :: NameSet, -- ^ After the renamer, this contains a superset of the
123 -- Names of the other binders in this binding group that
124 -- are free in the RHS of the defn
125 -- Before renaming, and after typechecking,
126 -- the field is unused; it's just an error thunk
128 fun_tick :: Maybe (Int,[Id]) -- ^ This is the (optional) module-local tick number.
131 | PatBind { -- The pattern is never a simple variable;
132 -- That case is done by FunBind
134 pat_rhs :: GRHSs idR,
135 pat_rhs_ty :: PostTcType, -- Type of the GRHSs
136 bind_fvs :: NameSet -- Same as for FunBind
139 | VarBind { -- Dictionary binding and suchlike
140 var_id :: idL, -- All VarBinds are introduced by the type checker
141 var_rhs :: LHsExpr idR, -- Located only for consistency
142 var_inline :: Bool -- True <=> inline this binding regardless
143 -- (used for implication constraints only)
146 | AbsBinds { -- Binds abstraction; TRANSLATION
148 abs_ev_vars :: [EvVar], -- Includes equality constraints
150 -- AbsBinds only gets used when idL = idR after renaming,
151 -- but these need to be idL's for the collect... code in HsUtil to have
153 abs_exports :: [([TyVar], idL, idL, TcSpecPrags)], -- (tvs, poly_id, mono_id, prags)
155 abs_ev_binds :: TcEvBinds, -- Evidence bindings
156 abs_binds :: LHsBinds idL -- Typechecked user bindings
158 deriving (Data, Typeable)
159 -- Consider (AbsBinds tvs ds [(ftvs, poly_f, mono_f) binds]
161 -- Creates bindings for (polymorphic, overloaded) poly_f
162 -- in terms of monomorphic, non-overloaded mono_f
165 -- 1. 'binds' binds mono_f
166 -- 2. ftvs is a subset of tvs
167 -- 3. ftvs includes all tyvars free in ds
169 -- See section 9 of static semantics paper for more details.
170 -- (You can get a PhD for explaining the True Meaning
171 -- of this last construct.)
173 placeHolderNames :: NameSet
174 -- Used for the NameSet in FunBind and PatBind prior to the renamer
175 placeHolderNames = panic "placeHolderNames"
178 instance (OutputableBndr idL, OutputableBndr idR) => Outputable (HsLocalBindsLR idL idR) where
179 ppr (HsValBinds bs) = ppr bs
180 ppr (HsIPBinds bs) = ppr bs
181 ppr EmptyLocalBinds = empty
183 instance (OutputableBndr idL, OutputableBndr idR) => Outputable (HsValBindsLR idL idR) where
184 ppr (ValBindsIn binds sigs)
185 = pprValBindsForUser binds sigs
187 ppr (ValBindsOut sccs sigs)
188 = getPprStyle $ \ sty ->
189 if debugStyle sty then -- Print with sccs showing
190 vcat (map ppr sigs) $$ vcat (map ppr_scc sccs)
192 pprValBindsForUser (unionManyBags (map snd sccs)) sigs
194 ppr_scc (rec_flag, binds) = pp_rec rec_flag <+> pprLHsBinds binds
195 pp_rec Recursive = ptext (sLit "rec")
196 pp_rec NonRecursive = ptext (sLit "nonrec")
198 -- *not* pprLHsBinds because we don't want braces; 'let' and
199 -- 'where' include a list of HsBindGroups and we don't want
200 -- several groups of bindings each with braces around.
201 -- Sort by location before printing
202 pprValBindsForUser :: (OutputableBndr idL, OutputableBndr idR, OutputableBndr id2)
203 => LHsBindsLR idL idR -> [LSig id2] -> SDoc
204 pprValBindsForUser binds sigs
205 = pprDeeperList vcat (map snd (sort_by_loc decls))
208 decls :: [(SrcSpan, SDoc)]
209 decls = [(loc, ppr sig) | L loc sig <- sigs] ++
210 [(loc, ppr bind) | L loc bind <- bagToList binds]
212 sort_by_loc decls = sortLe (\(l1,_) (l2,_) -> l1 <= l2) decls
214 pprLHsBinds :: (OutputableBndr idL, OutputableBndr idR) => LHsBindsLR idL idR -> SDoc
216 | isEmptyLHsBinds binds = empty
217 | otherwise = lbrace <+> pprDeeperList vcat (map ppr (bagToList binds)) <+> rbrace
220 emptyLocalBinds :: HsLocalBindsLR a b
221 emptyLocalBinds = EmptyLocalBinds
223 isEmptyLocalBinds :: HsLocalBindsLR a b -> Bool
224 isEmptyLocalBinds (HsValBinds ds) = isEmptyValBinds ds
225 isEmptyLocalBinds (HsIPBinds ds) = isEmptyIPBinds ds
226 isEmptyLocalBinds EmptyLocalBinds = True
228 isEmptyValBinds :: HsValBindsLR a b -> Bool
229 isEmptyValBinds (ValBindsIn ds sigs) = isEmptyLHsBinds ds && null sigs
230 isEmptyValBinds (ValBindsOut ds sigs) = null ds && null sigs
232 emptyValBindsIn, emptyValBindsOut :: HsValBindsLR a b
233 emptyValBindsIn = ValBindsIn emptyBag []
234 emptyValBindsOut = ValBindsOut [] []
236 emptyLHsBinds :: LHsBindsLR idL idR
237 emptyLHsBinds = emptyBag
239 isEmptyLHsBinds :: LHsBindsLR idL idR -> Bool
240 isEmptyLHsBinds = isEmptyBag
243 plusHsValBinds :: HsValBinds a -> HsValBinds a -> HsValBinds a
244 plusHsValBinds (ValBindsIn ds1 sigs1) (ValBindsIn ds2 sigs2)
245 = ValBindsIn (ds1 `unionBags` ds2) (sigs1 ++ sigs2)
246 plusHsValBinds (ValBindsOut ds1 sigs1) (ValBindsOut ds2 sigs2)
247 = ValBindsOut (ds1 ++ ds2) (sigs1 ++ sigs2)
259 f1p = /\ tvs -> \ [d1,d2] -> letrec DBINDS and BIND
262 gp = ...same again, with gm instead of fm
264 This is a pretty bad translation, because it duplicates all the bindings.
265 So the desugarer tries to do a better job:
267 fp = /\ [a,b] -> \ [d1,d2] -> case tp [a,b] [d1,d2] of
271 tp = /\ [a,b] -> \ [d1,d2] -> letrec DBINDS and BIND
275 instance (OutputableBndr idL, OutputableBndr idR) => Outputable (HsBindLR idL idR) where
276 ppr mbind = ppr_monobind mbind
278 ppr_monobind :: (OutputableBndr idL, OutputableBndr idR) => HsBindLR idL idR -> SDoc
280 ppr_monobind (PatBind { pat_lhs = pat, pat_rhs = grhss })
281 = pprPatBind pat grhss
282 ppr_monobind (VarBind { var_id = var, var_rhs = rhs })
283 = sep [pprBndr CaseBind var, nest 2 $ equals <+> pprExpr (unLoc rhs)]
284 ppr_monobind (FunBind { fun_id = fun, fun_infix = inf,
286 fun_matches = matches,
288 = pprTicks empty (case tick of
290 Just t -> text "-- tick id = " <> ppr t)
291 $$ pprFunBind (unLoc fun) inf matches
292 $$ ifPprDebug (ppr wrap)
294 ppr_monobind (AbsBinds { abs_tvs = tyvars, abs_ev_vars = dictvars
295 , abs_exports = exports, abs_binds = val_binds
296 , abs_ev_binds = ev_binds })
297 = sep [ptext (sLit "AbsBinds"),
298 brackets (interpp'SP tyvars),
299 brackets (interpp'SP dictvars),
300 brackets (sep (punctuate comma (map ppr_exp exports)))]
302 nest 2 ( vcat [pprBndr LetBind x | (_,x,_,_) <- exports]
303 -- Print type signatures
304 $$ pprLHsBinds val_binds )
306 ifPprDebug (ppr ev_binds)
308 ppr_exp (tvs, gbl, lcl, prags)
309 = vcat [ppr gbl <+> ptext (sLit "<=") <+> ppr tvs <+> ppr lcl,
310 nest 2 (pprTcSpecPrags gbl prags)]
315 pprTicks :: SDoc -> SDoc -> SDoc
316 -- Print stuff about ticks only when -dppr-debug is on, to avoid
317 -- them appearing in error messages (from the desugarer); see Trac # 3263
318 pprTicks pp_no_debug pp_when_debug
319 = getPprStyle (\ sty -> if debugStyle sty then pp_when_debug
323 %************************************************************************
325 Implicit parameter bindings
327 %************************************************************************
333 TcEvBinds -- Only in typechecker output; binds
334 -- uses of the implicit parameters
335 deriving (Data, Typeable)
337 isEmptyIPBinds :: HsIPBinds id -> Bool
338 isEmptyIPBinds (IPBinds is ds) = null is && isEmptyTcEvBinds ds
340 type LIPBind id = Located (IPBind id)
342 -- | Implicit parameter bindings.
347 deriving (Data, Typeable)
349 instance (OutputableBndr id) => Outputable (HsIPBinds id) where
350 ppr (IPBinds bs ds) = pprDeeperList vcat (map ppr bs)
353 instance (OutputableBndr id) => Outputable (IPBind id) where
354 ppr (IPBind id rhs) = pprBndr LetBind id <+> equals <+> pprExpr (unLoc rhs)
358 %************************************************************************
360 \subsection{Coercion functions}
362 %************************************************************************
365 -- A HsWrapper is an expression with a hole in it
366 -- We need coercions to have concrete form so that we can zonk them
369 = WpHole -- The identity coercion
371 | WpCompose HsWrapper HsWrapper
372 -- (wrap1 `WpCompse` wrap2)[e] = wrap1[ wrap2[ e ]]
374 -- Hence (\a. []) `WpCompose` (\b. []) = (\a b. [])
375 -- But ([] a) `WpCompose` ([] b) = ([] b a)
377 | WpCast Coercion -- A cast: [] `cast` co
378 -- Guaranteed not the identity coercion
380 -- Evidence abstraction and application
381 -- (both dictionaries and coercions)
382 | WpEvLam EvVar -- \d. [] the 'd' is an evidence variable
383 | WpEvApp EvTerm -- [] d the 'd' is evidence for a constraint
385 -- Type abstraction and application
386 | WpTyLam TyVar -- \a. [] the 'a' is a type variable (not coercion var)
387 | WpTyApp Type -- [] t the 't' is a type (not coercion)
390 | WpLet TcEvBinds -- Non-empty (or possibly non-empty) evidence bindings,
391 -- so that the identity coercion is always exactly WpHole
392 deriving (Data, Typeable)
396 = TcEvBinds -- Mutable evidence bindings
397 EvBindsVar -- Mutable because they are updated "later"
398 -- when an implication constraint is solved
400 | EvBinds -- Immutable after zonking
405 data EvBindsVar = EvBindsVar (IORef EvBindMap) Unique
406 -- The Unique is only for debug printing
409 type EvBindMap = VarEnv EvBind
411 emptyEvBindMap :: EvBindMap
412 emptyEvBindMap = emptyVarEnv
414 extendEvBinds :: EvBindMap -> EvVar -> EvTerm -> EvBindMap
415 extendEvBinds bs v t = extendVarEnv bs v (EvBind v t)
417 lookupEvBind :: EvBindMap -> EvVar -> Maybe EvBind
418 lookupEvBind = lookupVarEnv
420 evBindMapBinds :: EvBindMap -> Bag EvBind
421 evBindMapBinds = foldVarEnv consBag emptyBag
424 instance Data TcEvBinds where
425 -- Placeholder; we can't travers into TcEvBinds
426 toConstr _ = abstractConstr "TcEvBinds"
427 gunfold _ _ = error "gunfold"
428 dataTypeOf _ = mkNoRepType "TcEvBinds"
430 -- All evidence is bound by EvBinds; no side effects
431 data EvBind = EvBind EvVar EvTerm
434 = EvId EvId -- Term-level variable-to-variable bindings
435 -- (no coercion variables! they come via EvCoercion)
437 | EvCoercion Coercion -- Coercion bindings
439 | EvCast EvVar Coercion -- d |> co
441 | EvDFunApp DFunId -- Dictionary instance application
444 | EvSuperClass DictId Int -- n'th superclass. Used for both equalities and
445 -- dictionaries, even though the former have no
446 -- selector Id. We count up from _0_
448 deriving( Data, Typeable)
450 evVarTerm :: EvVar -> EvTerm
451 evVarTerm v | isCoVar v = EvCoercion (mkCoVarCoercion v)
455 Note [EvBinds/EvTerm]
456 ~~~~~~~~~~~~~~~~~~~~~
457 How evidence is created and updated. Bindings for dictionaries,
458 and coercions and implicit parameters are carried around in TcEvBinds
459 which during constraint generation and simplification is always of the
460 form (TcEvBinds ref). After constraint simplification is finished it
461 will be transformed to t an (EvBinds ev_bag).
463 Evidence for coercions *SHOULD* be filled in using the TcEvBinds
464 However, all EvVars that correspond to *wanted* coercion terms in
465 an EvBind must be mutable variables so that they can be readily
466 inlined (by zonking) after constraint simplification is finished.
468 Conclusion: a new wanted coercion variable should be made mutable.
469 [Notice though that evidence variables that bind coercion terms
470 from super classes will be "given" and hence rigid]
474 emptyTcEvBinds :: TcEvBinds
475 emptyTcEvBinds = EvBinds emptyBag
477 isEmptyTcEvBinds :: TcEvBinds -> Bool
478 isEmptyTcEvBinds (EvBinds b) = isEmptyBag b
479 isEmptyTcEvBinds (TcEvBinds {}) = panic "isEmptyTcEvBinds"
481 (<.>) :: HsWrapper -> HsWrapper -> HsWrapper
484 c1 <.> c2 = c1 `WpCompose` c2
486 mkWpTyApps :: [Type] -> HsWrapper
487 mkWpTyApps tys = mk_co_app_fn WpTyApp tys
489 mkWpEvApps :: [EvTerm] -> HsWrapper
490 mkWpEvApps args = mk_co_app_fn WpEvApp args
492 mkWpEvVarApps :: [EvVar] -> HsWrapper
493 mkWpEvVarApps vs = mkWpEvApps (map evVarTerm vs)
495 mkWpTyLams :: [TyVar] -> HsWrapper
496 mkWpTyLams ids = mk_co_lam_fn WpTyLam ids
498 mkWpLams :: [Var] -> HsWrapper
499 mkWpLams ids = mk_co_lam_fn WpEvLam ids
501 mkWpLet :: TcEvBinds -> HsWrapper
502 -- This no-op is a quite a common case
503 mkWpLet (EvBinds b) | isEmptyBag b = WpHole
504 mkWpLet ev_binds = WpLet ev_binds
506 mk_co_lam_fn :: (a -> HsWrapper) -> [a] -> HsWrapper
507 mk_co_lam_fn f as = foldr (\x wrap -> f x `WpCompose` wrap) WpHole as
509 mk_co_app_fn :: (a -> HsWrapper) -> [a] -> HsWrapper
510 -- For applications, the *first* argument must
511 -- come *last* in the composition sequence
512 mk_co_app_fn f as = foldr (\x wrap -> wrap `WpCompose` f x) WpHole as
514 idHsWrapper :: HsWrapper
517 isIdHsWrapper :: HsWrapper -> Bool
518 isIdHsWrapper WpHole = True
519 isIdHsWrapper _ = False
525 instance Outputable HsWrapper where
526 ppr co_fn = pprHsWrapper (ptext (sLit "<>")) co_fn
528 pprHsWrapper :: SDoc -> HsWrapper -> SDoc
529 -- In debug mode, print the wrapper
530 -- otherwise just print what's inside
531 pprHsWrapper doc wrap
532 = getPprStyle (\ s -> if debugStyle s then (help (add_parens doc) wrap False) else doc)
534 help :: (Bool -> SDoc) -> HsWrapper -> Bool -> SDoc
535 -- True <=> appears in function application position
536 -- False <=> appears as body of let or lambda
538 help it (WpCompose f1 f2) = help (help it f2) f1
539 help it (WpCast co) = add_parens $ sep [it False, nest 2 (ptext (sLit "|>")
540 <+> pprParendType co)]
541 help it (WpEvApp id) = no_parens $ sep [it True, nest 2 (ppr id)]
542 help it (WpTyApp ty) = no_parens $ sep [it True, ptext (sLit "@") <+> pprParendType ty]
543 help it (WpEvLam id) = add_parens $ sep [ ptext (sLit "\\") <> pp_bndr id, it False]
544 help it (WpTyLam tv) = add_parens $ sep [ptext (sLit "/\\") <> pp_bndr tv, it False]
545 help it (WpLet binds) = add_parens $ sep [ptext (sLit "let") <+> braces (ppr binds), it False]
547 pp_bndr v = pprBndr LambdaBind v <> dot
549 add_parens, no_parens :: SDoc -> Bool -> SDoc
550 add_parens d True = parens d
551 add_parens d False = d
554 instance Outputable TcEvBinds where
555 ppr (TcEvBinds v) = ppr v
556 ppr (EvBinds bs) = ptext (sLit "EvBinds") <> braces (ppr bs)
558 instance Outputable EvBindsVar where
559 ppr (EvBindsVar _ u) = ptext (sLit "EvBindsVar") <> angleBrackets (ppr u)
561 instance Outputable EvBind where
562 ppr (EvBind v e) = ppr v <+> equals <+> ppr e
564 instance Outputable EvTerm where
566 ppr (EvCast v co) = ppr v <+> (ptext (sLit "`cast`")) <+> pprParendType co
567 ppr (EvCoercion co) = ppr co
568 ppr (EvSuperClass d n) = ptext (sLit "sc") <> parens (ppr (d,n))
569 ppr (EvDFunApp df tys ts) = ppr df <+> sep [ char '@' <> ppr tys
573 %************************************************************************
575 \subsection{@Sig@: type signatures and value-modifying user pragmas}
577 %************************************************************************
579 It is convenient to lump ``value-modifying'' user-pragmas (e.g.,
580 ``specialise this function to these four types...'') in with type
581 signatures. Then all the machinery to move them into place, etc.,
585 type LSig name = Located (Sig name)
587 data Sig name -- Signatures and pragmas
588 = -- An ordinary type signature
589 -- f :: Num a => a -> a
590 TypeSig (Located name) (LHsType name)
592 -- A type signature in generated code, notably the code
593 -- generated for record selectors. We simply record
594 -- the desired Id itself, replete with its name, type
595 -- and IdDetails. Otherwise it's just like a type
596 -- signature: there should be an accompanying binding
599 -- An ordinary fixity declaration
601 | FixSig (FixitySig name)
605 | InlineSig (Located name) -- Function name
606 InlinePragma -- Never defaultInlinePragma
608 -- A specialisation pragma
609 -- {-# SPECIALISE f :: Int -> Int #-}
610 | SpecSig (Located name) -- Specialise a function or datatype ...
611 (LHsType name) -- ... to these types
612 InlinePragma -- The pragma on SPECIALISE_INLINE form
613 -- If it's just defaultInlinePragma, then we said
614 -- SPECIALISE, not SPECIALISE_INLINE
616 -- A specialisation pragma for instance declarations only
617 -- {-# SPECIALISE instance Eq [Int] #-}
618 | SpecInstSig (LHsType name) -- (Class tys); should be a specialisation of the
619 -- current instance decl
620 deriving (Data, Typeable)
623 type LFixitySig name = Located (FixitySig name)
624 data FixitySig name = FixitySig (Located name) Fixity
625 deriving (Data, Typeable)
627 -- TsSpecPrags conveys pragmas from the type checker to the desugarer
629 = IsDefaultMethod -- Super-specialised: a default method should
630 -- be macro-expanded at every call site
631 | SpecPrags [Located TcSpecPrag]
632 deriving (Data, Typeable)
636 HsWrapper -- An wrapper, that specialises the polymorphic function
637 InlinePragma -- Inlining spec for the specialised function
638 deriving (Data, Typeable)
640 noSpecPrags :: TcSpecPrags
641 noSpecPrags = SpecPrags []
643 hasSpecPrags :: TcSpecPrags -> Bool
644 hasSpecPrags (SpecPrags ps) = not (null ps)
645 hasSpecPrags IsDefaultMethod = False
647 isDefaultMethod :: TcSpecPrags -> Bool
648 isDefaultMethod IsDefaultMethod = True
649 isDefaultMethod (SpecPrags {}) = False
654 okBindSig :: Sig a -> Bool
657 okHsBootSig :: Sig a -> Bool
658 okHsBootSig (TypeSig _ _) = True
659 okHsBootSig (FixSig _) = True
660 okHsBootSig _ = False
662 okClsDclSig :: Sig a -> Bool
663 okClsDclSig (SpecInstSig _) = False
664 okClsDclSig _ = True -- All others OK
666 okInstDclSig :: Sig a -> Bool
667 okInstDclSig (TypeSig _ _) = False
668 okInstDclSig (FixSig _) = False
669 okInstDclSig _ = True
671 sigForThisGroup :: NameSet -> LSig Name -> Bool
672 sigForThisGroup ns sig
673 = case sigName sig of
675 Just n -> n `elemNameSet` ns
677 sigName :: LSig name -> Maybe name
678 sigName (L _ sig) = sigNameNoLoc sig
680 sigNameNoLoc :: Sig name -> Maybe name
681 sigNameNoLoc (TypeSig n _) = Just (unLoc n)
682 sigNameNoLoc (SpecSig n _ _) = Just (unLoc n)
683 sigNameNoLoc (InlineSig n _) = Just (unLoc n)
684 sigNameNoLoc (FixSig (FixitySig n _)) = Just (unLoc n)
685 sigNameNoLoc _ = Nothing
687 isFixityLSig :: LSig name -> Bool
688 isFixityLSig (L _ (FixSig {})) = True
689 isFixityLSig _ = False
691 isVanillaLSig :: LSig name -> Bool -- User type signatures
692 -- A badly-named function, but it's part of the GHCi (used
693 -- by Haddock) so I don't want to change it gratuitously.
694 isVanillaLSig (L _(TypeSig {})) = True
695 isVanillaLSig _ = False
697 isTypeLSig :: LSig name -> Bool -- Type signatures
698 isTypeLSig (L _(TypeSig {})) = True
699 isTypeLSig (L _(IdSig {})) = True
702 isSpecLSig :: LSig name -> Bool
703 isSpecLSig (L _(SpecSig {})) = True
706 isSpecInstLSig :: LSig name -> Bool
707 isSpecInstLSig (L _ (SpecInstSig {})) = True
708 isSpecInstLSig _ = False
710 isPragLSig :: LSig name -> Bool
711 -- Identifies pragmas
712 isPragLSig (L _ (SpecSig {})) = True
713 isPragLSig (L _ (InlineSig {})) = True
716 isInlineLSig :: LSig name -> Bool
717 -- Identifies inline pragmas
718 isInlineLSig (L _ (InlineSig {})) = True
719 isInlineLSig _ = False
721 hsSigDoc :: Sig name -> SDoc
722 hsSigDoc (TypeSig {}) = ptext (sLit "type signature")
723 hsSigDoc (IdSig {}) = ptext (sLit "id signature")
724 hsSigDoc (SpecSig {}) = ptext (sLit "SPECIALISE pragma")
725 hsSigDoc (InlineSig {}) = ptext (sLit "INLINE pragma")
726 hsSigDoc (SpecInstSig {}) = ptext (sLit "SPECIALISE instance pragma")
727 hsSigDoc (FixSig {}) = ptext (sLit "fixity declaration")
730 Signature equality is used when checking for duplicate signatures
733 eqHsSig :: Eq a => LSig a -> LSig a -> Bool
734 eqHsSig (L _ (FixSig (FixitySig n1 _))) (L _ (FixSig (FixitySig n2 _))) = unLoc n1 == unLoc n2
735 eqHsSig (L _ (IdSig n1)) (L _ (IdSig n2)) = n1 == n2
736 eqHsSig (L _ (TypeSig n1 _)) (L _ (TypeSig n2 _)) = unLoc n1 == unLoc n2
737 eqHsSig (L _ (InlineSig n1 _)) (L _ (InlineSig n2 _)) = unLoc n1 == unLoc n2
738 -- For specialisations, we don't have equality over
739 -- HsType, so it's not convenient to spot duplicate
740 -- specialisations here. Check for this later, when we're in Type land
741 eqHsSig _other1 _other2 = False
745 instance (OutputableBndr name) => Outputable (Sig name) where
746 ppr sig = ppr_sig sig
748 ppr_sig :: OutputableBndr name => Sig name -> SDoc
749 ppr_sig (TypeSig var ty) = pprVarSig (unLoc var) (ppr ty)
750 ppr_sig (IdSig id) = pprVarSig id (ppr (varType id))
751 ppr_sig (FixSig fix_sig) = ppr fix_sig
752 ppr_sig (SpecSig var ty inl) = pragBrackets (pprSpec var (ppr ty) inl)
753 ppr_sig (InlineSig var inl) = pragBrackets (ppr inl <+> ppr var)
754 ppr_sig (SpecInstSig ty) = pragBrackets (ptext (sLit "SPECIALIZE instance") <+> ppr ty)
756 instance Outputable name => Outputable (FixitySig name) where
757 ppr (FixitySig name fixity) = sep [ppr fixity, ppr name]
759 pragBrackets :: SDoc -> SDoc
760 pragBrackets doc = ptext (sLit "{-#") <+> doc <+> ptext (sLit "#-}")
762 pprVarSig :: (Outputable id) => id -> SDoc -> SDoc
763 pprVarSig var pp_ty = sep [ppr var <+> dcolon, nest 2 pp_ty]
765 pprSpec :: (Outputable id) => id -> SDoc -> InlinePragma -> SDoc
766 pprSpec var pp_ty inl = ptext (sLit "SPECIALIZE") <+> pp_inl <+> pprVarSig var pp_ty
768 pp_inl | isDefaultInlinePragma inl = empty
769 | otherwise = ppr inl
771 pprTcSpecPrags :: Outputable id => id -> TcSpecPrags -> SDoc
772 pprTcSpecPrags _ IsDefaultMethod = ptext (sLit "<default method>")
773 pprTcSpecPrags gbl (SpecPrags ps) = vcat (map (pprSpecPrag gbl) ps)
775 pprSpecPrag :: Outputable id => id -> Located TcSpecPrag -> SDoc
776 pprSpecPrag var (L _ (SpecPrag _expr inl)) = pprSpec var (ptext (sLit "<type>")) inl
778 instance Outputable TcSpecPrag where
779 ppr (SpecPrag _ p) = ptext (sLit "SpecPrag") <+> ppr p