2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[HsBinds]{Abstract syntax: top-level bindings and signatures}
6 Datatype for: @HsBinds@, @Bind@, @Sig@, @MonoBinds@.
11 #include "HsVersions.h"
13 import {-# SOURCE #-} HsExpr ( pprExpr, HsExpr )
14 import {-# SOURCE #-} HsMatches ( pprMatches, Match, pprGRHSs, GRHSs )
17 import HsTypes ( HsType, cmpHsType )
18 import HsImpExp ( IE(..), ieName )
19 import CoreSyn ( CoreExpr )
20 import PprCore () -- Instances for Outputable
24 import Name ( Name, isUnboundName )
25 import NameSet ( NameSet, elemNameSet, nameSetToList )
26 import BasicTypes ( RecFlag(..), Fixity )
29 import SrcLoc ( SrcLoc )
31 import Util ( thenCmp )
34 %************************************************************************
36 \subsection{Bindings: @HsBinds@}
38 %************************************************************************
40 The following syntax may produce new syntax which is not part of the input,
41 and which is instead a translation of the input to the typechecker.
42 Syntax translations are marked TRANSLATION in comments. New empty
43 productions are useful in development but may not appear in the final
46 Collections of bindings, created by dependency analysis and translation:
49 data HsBinds id pat -- binders and bindees
52 | ThenBinds (HsBinds id pat)
55 | MonoBind (MonoBinds id pat)
56 [Sig id] -- Empty on typechecker output
61 nullBinds :: HsBinds id pat -> Bool
63 nullBinds EmptyBinds = True
64 nullBinds (ThenBinds b1 b2) = nullBinds b1 && nullBinds b2
65 nullBinds (MonoBind b _ _) = nullMonoBinds b
67 mkMonoBind :: MonoBinds id pat -> [Sig id] -> RecFlag -> HsBinds id pat
68 mkMonoBind EmptyMonoBinds _ _ = EmptyBinds
69 mkMonoBind mbinds sigs is_rec = MonoBind mbinds sigs is_rec
73 instance (Outputable pat, Outputable id) =>
74 Outputable (HsBinds id pat) where
75 ppr binds = ppr_binds binds
77 ppr_binds EmptyBinds = empty
78 ppr_binds (ThenBinds binds1 binds2)
79 = ($$) (ppr_binds binds1) (ppr_binds binds2)
80 ppr_binds (MonoBind bind sigs is_rec)
81 = vcat [ifNotPprForUser (ptext rec_str),
86 rec_str = case is_rec of
87 Recursive -> SLIT("{- rec -}")
88 NonRecursive -> SLIT("{- nonrec -}")
91 %************************************************************************
93 \subsection{Bindings: @MonoBinds@}
95 %************************************************************************
97 Global bindings (where clauses)
100 data MonoBinds id pat
103 | AndMonoBinds (MonoBinds id pat)
106 | FunMonoBind id -- Used for both functions f x = e
107 -- and variables f = \x -> e
108 -- Reason: the Match stuff lets us have an optional
109 -- result type sig f :: a->a = ...mentions a...
110 Bool -- True => infix declaration
114 | PatMonoBind pat -- The pattern is never a simple variable;
115 -- That case is done by FunMonoBind
119 | VarMonoBind id -- TRANSLATION
122 | CoreMonoBind id -- TRANSLATION
123 CoreExpr -- No zonking; this is a final CoreExpr with Ids and Types!
125 | AbsBinds -- Binds abstraction; TRANSLATION
126 [TyVar] -- Type variables
128 [([TyVar], id, id)] -- (type variables, polymorphic, momonmorphic) triples
129 NameSet -- Set of *polymorphic* variables that have an INLINE pragma
130 (MonoBinds id pat) -- The "business end"
132 -- Creates bindings for *new* (polymorphic, overloaded) locals
133 -- in terms of *old* (monomorphic, non-overloaded) ones.
135 -- See section 9 of static semantics paper for more details.
136 -- (You can get a PhD for explaining the True Meaning
137 -- of this last construct.)
149 f1p = /\ tvs -> \ [d1,d2] -> letrec DBINDS and BIND
152 gp = ...same again, with gm instead of fm
154 This is a pretty bad translation, because it duplicates all the bindings.
155 So the desugarer tries to do a better job:
157 fp = /\ [a,b] -> \ [d1,d2] -> case tp [a,b] [d1,d2] of
161 p = /\ [a,b] -> \ [d1,d2] -> letrec DBINDS and BIND
165 -- We keep the invariant that a MonoBinds is only empty
166 -- if it is exactly EmptyMonoBinds
168 nullMonoBinds :: MonoBinds id pat -> Bool
169 nullMonoBinds EmptyMonoBinds = True
170 nullMonoBinds other_monobind = False
172 andMonoBinds :: MonoBinds id pat -> MonoBinds id pat -> MonoBinds id pat
173 andMonoBinds EmptyMonoBinds mb = mb
174 andMonoBinds mb EmptyMonoBinds = mb
175 andMonoBinds mb1 mb2 = AndMonoBinds mb1 mb2
177 andMonoBindList :: [MonoBinds id pat] -> MonoBinds id pat
178 andMonoBindList binds
181 loop1 [] = EmptyMonoBinds
182 loop1 (EmptyMonoBinds : binds) = loop1 binds
183 loop1 (b:bs) = loop2 b bs
187 loop2 acc (EmptyMonoBinds : bs) = loop2 acc bs
188 loop2 acc (b:bs) = loop2 (acc `AndMonoBinds` b) bs
193 instance (Outputable id, Outputable pat) =>
194 Outputable (MonoBinds id pat) where
195 ppr mbind = ppr_monobind mbind
198 ppr_monobind :: (Outputable id, Outputable pat) => MonoBinds id pat -> SDoc
199 ppr_monobind EmptyMonoBinds = empty
200 ppr_monobind (AndMonoBinds binds1 binds2)
201 = ppr_monobind binds1 $$ ppr_monobind binds2
203 ppr_monobind (PatMonoBind pat grhss locn)
204 = sep [ppr pat, nest 4 (pprGRHSs False grhss)]
206 ppr_monobind (FunMonoBind fun inf matches locn)
207 = pprMatches (False, ppr fun) matches
208 -- ToDo: print infix if appropriate
210 ppr_monobind (VarMonoBind name expr)
211 = sep [ppr name <+> equals, nest 4 (pprExpr expr)]
213 ppr_monobind (CoreMonoBind name expr)
214 = sep [ppr name <+> equals, nest 4 (ppr expr)]
216 ppr_monobind (AbsBinds tyvars dictvars exports inlines val_binds)
217 = sep [ptext SLIT("AbsBinds"),
218 brackets (interpp'SP tyvars),
219 brackets (interpp'SP dictvars),
220 brackets (sep (punctuate comma (map ppr exports))),
221 brackets (interpp'SP (nameSetToList inlines))]
223 nest 4 (ppr val_binds)
226 %************************************************************************
228 \subsection{@Sig@: type signatures and value-modifying user pragmas}
230 %************************************************************************
232 It is convenient to lump ``value-modifying'' user-pragmas (e.g.,
233 ``specialise this function to these four types...'') in with type
234 signatures. Then all the machinery to move them into place, etc.,
239 = Sig name -- a bog-std type signature
243 | ClassOpSig name -- Selector name
244 name -- Default-method name (if any)
245 Bool -- True <=> there is an explicit, programmer-supplied
246 -- default declaration in the class decl
250 | SpecSig name -- specialise a function or datatype ...
251 (HsType name) -- ... to these types
254 | InlineSig name -- INLINE f
258 | NoInlineSig name -- NOINLINE f
262 | SpecInstSig (HsType name) -- (Class tys); should be a specialisation of the
263 -- current instance decl
266 | FixSig (FixitySig name) -- Fixity declaration
268 | DeprecSig (Deprecation name) -- DEPRECATED
271 data FixitySig name = FixitySig name Fixity SrcLoc
273 -- We use exported entities for things to deprecate. Cunning trick (hack?):
274 -- `IEModuleContents undefined' is used for module deprecation.
275 data Deprecation name = Deprecation (IE name) DeprecTxt
277 type DeprecTxt = FAST_STRING -- reason/explanation for deprecation
281 okBindSig :: NameSet -> Sig Name -> Bool
282 okBindSig ns (ClassOpSig _ _ _ _ _) = False
283 okBindSig ns sig = sigForThisGroup ns sig
285 okClsDclSig :: NameSet -> Sig Name -> Bool
286 okClsDclSig ns (Sig _ _ _) = False
287 okClsDclSig ns sig = sigForThisGroup ns sig
289 okInstDclSig :: NameSet -> Sig Name -> Bool
290 okInstDclSig ns (Sig _ _ _) = False
291 okInstDclSig ns (FixSig _) = False
292 okInstDclSig ns (SpecInstSig _ _) = True
293 okInstDclSig ns sig = sigForThisGroup ns sig
295 sigForThisGroup ns sig
296 = case sigName sig of
298 Just n | isUnboundName n -> True -- Don't complain about an unbound name again
299 | otherwise -> n `elemNameSet` ns
301 sigsForMe :: (name -> Bool) -> [Sig name] -> [Sig name]
303 = filter sig_for_me sigs
305 sig_for_me sig = case sigName sig of
309 sigName :: Sig name -> Maybe name
310 sigName (Sig n _ _) = Just n
311 sigName (ClassOpSig n _ _ _ _) = Just n
312 sigName (SpecSig n _ _) = Just n
313 sigName (InlineSig n _ _) = Just n
314 sigName (NoInlineSig n _ _) = Just n
315 sigName (FixSig (FixitySig n _ _)) = Just n
316 sigName (DeprecSig (Deprecation d _) _) = case d of
317 IEModuleContents _ -> Nothing
318 other -> Just (ieName d)
319 sigName other = Nothing
321 isFixitySig :: Sig name -> Bool
322 isFixitySig (FixSig _) = True
323 isFixitySig _ = False
325 isClassOpSig :: Sig name -> Bool
326 isClassOpSig (ClassOpSig _ _ _ _ _) = True
327 isClassOpSig _ = False
329 isPragSig :: Sig name -> Bool
330 -- Identifies pragmas
331 isPragSig (SpecSig _ _ _) = True
332 isPragSig (InlineSig _ _ _) = True
333 isPragSig (NoInlineSig _ _ _) = True
334 isPragSig (SpecInstSig _ _) = True
335 isPragSig (DeprecSig _ _) = True
336 isPragSig other = False
340 hsSigDoc (Sig _ _ loc) = (SLIT("type signature"),loc)
341 hsSigDoc (ClassOpSig _ _ _ _ loc) = (SLIT("class-method type signature"), loc)
342 hsSigDoc (SpecSig _ _ loc) = (SLIT("SPECIALISE pragma"),loc)
343 hsSigDoc (InlineSig _ _ loc) = (SLIT("INLINE pragma"),loc)
344 hsSigDoc (NoInlineSig _ _ loc) = (SLIT("NOINLINE pragma"),loc)
345 hsSigDoc (SpecInstSig _ loc) = (SLIT("SPECIALISE instance pragma"),loc)
346 hsSigDoc (FixSig (FixitySig _ _ loc)) = (SLIT("fixity declaration"), loc)
347 hsSigDoc (DeprecSig _ loc) = (SLIT("DEPRECATED pragma"), loc)
351 instance (Outputable name) => Outputable (Sig name) where
352 ppr sig = ppr_sig sig
354 ppr_sig :: Outputable name => Sig name -> SDoc
355 ppr_sig (Sig var ty _)
356 = sep [ppr var <+> dcolon, nest 4 (ppr ty)]
358 ppr_sig (ClassOpSig var _ _ ty _)
359 = sep [ppr var <+> dcolon, nest 4 (ppr ty)]
361 ppr_sig (SpecSig var ty _)
362 = sep [ hsep [text "{-# SPECIALIZE", ppr var, dcolon],
363 nest 4 (ppr ty <+> text "#-}")
366 ppr_sig (InlineSig var phase _)
367 = hsep [text "{-# INLINE", ppr_phase phase, ppr var, text "#-}"]
369 ppr_sig (NoInlineSig var phase _)
370 = hsep [text "{-# NOINLINE", ppr_phase phase, ppr var, text "#-}"]
372 ppr_sig (SpecInstSig ty _)
373 = hsep [text "{-# SPECIALIZE instance", ppr ty, text "#-}"]
375 ppr_sig (FixSig fix_sig) = ppr fix_sig
377 ppr_sig (DeprecSig deprec _) = ppr deprec
379 instance Outputable name => Outputable (FixitySig name) where
380 ppr (FixitySig name fixity loc) = sep [ppr fixity, ppr name]
382 instance Outputable name => Outputable (Deprecation name) where
383 ppr (Deprecation (IEModuleContents _) txt)
384 = hsep [text "{-# DEPRECATED", doubleQuotes (ppr txt), text "#-}"]
385 ppr (Deprecation thing txt)
386 = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]
388 ppr_phase :: Maybe Int -> SDoc
389 ppr_phase Nothing = empty
390 ppr_phase (Just n) = int n
393 Checking for distinct signatures; oh, so boring
397 cmpHsSig :: Sig Name -> Sig Name -> Ordering
398 cmpHsSig (Sig n1 _ _) (Sig n2 _ _) = n1 `compare` n2
399 cmpHsSig (DeprecSig (Deprecation ie1 _) _)
400 (DeprecSig (Deprecation ie2 _) _) = cmp_ie ie1 ie2
401 cmpHsSig (InlineSig n1 _ _) (InlineSig n2 _ _) = n1 `compare` n2
402 cmpHsSig (NoInlineSig n1 _ _) (NoInlineSig n2 _ _) = n1 `compare` n2
404 cmpHsSig (SpecInstSig ty1 _) (SpecInstSig ty2 _) = cmpHsType compare ty1 ty2
405 cmpHsSig (SpecSig n1 ty1 _) (SpecSig n2 ty2 _)
406 = -- may have many specialisations for one value;
407 -- but not ones that are exactly the same...
408 thenCmp (n1 `compare` n2) (cmpHsType compare ty1 ty2)
410 cmpHsSig other_1 other_2 -- Tags *must* be different
411 | (sig_tag other_1) _LT_ (sig_tag other_2) = LT
414 cmp_ie :: IE Name -> IE Name -> Ordering
415 cmp_ie (IEVar n1 ) (IEVar n2 ) = n1 `compare` n2
416 cmp_ie (IEThingAbs n1 ) (IEThingAbs n2 ) = n1 `compare` n2
417 cmp_ie (IEThingAll n1 ) (IEThingAll n2 ) = n1 `compare` n2
419 cmp_ie (IEThingWith n1 _) (IEThingWith n2 _) = n1 `compare` n2
420 cmp_ie (IEModuleContents _ ) (IEModuleContents _ ) = EQ
422 sig_tag (Sig n1 _ _) = (ILIT(1) :: FAST_INT)
423 sig_tag (SpecSig n1 _ _) = ILIT(2)
424 sig_tag (InlineSig n1 _ _) = ILIT(3)
425 sig_tag (NoInlineSig n1 _ _) = ILIT(4)
426 sig_tag (SpecInstSig _ _) = ILIT(5)
427 sig_tag (FixSig _) = ILIT(6)
428 sig_tag (DeprecSig _ _) = ILIT(7)
429 sig_tag _ = panic# "tag(RnBinds)"