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 )
18 import CoreSyn ( CoreExpr )
19 import PprCore () -- Instances for Outputable
23 import NameSet ( NameSet, nameSetToList )
24 import BasicTypes ( RecFlag(..), Fixity )
27 import SrcLoc ( SrcLoc )
31 %************************************************************************
33 \subsection{Bindings: @HsBinds@}
35 %************************************************************************
37 The following syntax may produce new syntax which is not part of the input,
38 and which is instead a translation of the input to the typechecker.
39 Syntax translations are marked TRANSLATION in comments. New empty
40 productions are useful in development but may not appear in the final
43 Collections of bindings, created by dependency analysis and translation:
46 data HsBinds id pat -- binders and bindees
49 | ThenBinds (HsBinds id pat)
52 | MonoBind (MonoBinds id pat)
53 [Sig id] -- Empty on typechecker output
58 nullBinds :: HsBinds id pat -> Bool
60 nullBinds EmptyBinds = True
61 nullBinds (ThenBinds b1 b2) = nullBinds b1 && nullBinds b2
62 nullBinds (MonoBind b _ _) = nullMonoBinds b
66 instance (Outputable pat, Outputable id) =>
67 Outputable (HsBinds id pat) where
68 ppr binds = ppr_binds binds
70 ppr_binds EmptyBinds = empty
71 ppr_binds (ThenBinds binds1 binds2)
72 = ($$) (ppr_binds binds1) (ppr_binds binds2)
73 ppr_binds (MonoBind bind sigs is_rec)
74 = vcat [ifNotPprForUser (ptext rec_str),
79 rec_str = case is_rec of
80 Recursive -> SLIT("{- rec -}")
81 NonRecursive -> SLIT("{- nonrec -}")
84 %************************************************************************
86 \subsection{Bindings: @MonoBinds@}
88 %************************************************************************
90 Global bindings (where clauses)
96 | AndMonoBinds (MonoBinds id pat)
104 Bool -- True => infix declaration
108 | VarMonoBind id -- TRANSLATION
111 | CoreMonoBind id -- TRANSLATION
112 CoreExpr -- No zonking; this is a final CoreExpr with Ids and Types!
114 | AbsBinds -- Binds abstraction; TRANSLATION
115 [TyVar] -- Type variables
117 [([TyVar], id, id)] -- (type variables, polymorphic, momonmorphic) triples
118 NameSet -- Set of *polymorphic* variables that have an INLINE pragma
119 (MonoBinds id pat) -- The "business end"
121 -- Creates bindings for *new* (polymorphic, overloaded) locals
122 -- in terms of *old* (monomorphic, non-overloaded) ones.
124 -- See section 9 of static semantics paper for more details.
125 -- (You can get a PhD for explaining the True Meaning
126 -- of this last construct.)
138 f1p = /\ tvs -> \ [d1,d2] -> letrec DBINDS and BIND
141 gp = ...same again, with gm instead of fm
143 This is a pretty bad translation, because it duplicates all the bindings.
144 So the desugarer tries to do a better job:
146 fp = /\ [a,b] -> \ [d1,d2] -> case tp [a,b] [d1,d2] of
150 p = /\ [a,b] -> \ [d1,d2] -> letrec DBINDS and BIND
154 nullMonoBinds :: MonoBinds id pat -> Bool
156 nullMonoBinds EmptyMonoBinds = True
157 nullMonoBinds (AndMonoBinds bs1 bs2) = nullMonoBinds bs1 && nullMonoBinds bs2
158 nullMonoBinds other_monobind = False
160 andMonoBinds :: MonoBinds id pat -> MonoBinds id pat -> MonoBinds id pat
161 andMonoBinds EmptyMonoBinds mb = mb
162 andMonoBinds mb EmptyMonoBinds = mb
163 andMonoBinds mb1 mb2 = AndMonoBinds mb1 mb2
165 andMonoBindList :: [MonoBinds id pat] -> MonoBinds id pat
166 andMonoBindList binds = foldr AndMonoBinds EmptyMonoBinds binds
170 instance (Outputable id, Outputable pat) =>
171 Outputable (MonoBinds id pat) where
172 ppr mbind = ppr_monobind mbind
175 ppr_monobind :: (Outputable id, Outputable pat) => MonoBinds id pat -> SDoc
176 ppr_monobind EmptyMonoBinds = empty
177 ppr_monobind (AndMonoBinds binds1 binds2)
178 = ppr_monobind binds1 $$ ppr_monobind binds2
180 ppr_monobind (PatMonoBind pat grhss locn)
181 = sep [ppr pat, nest 4 (pprGRHSs False grhss)]
183 ppr_monobind (FunMonoBind fun inf matches locn)
184 = pprMatches (False, ppr fun) matches
185 -- ToDo: print infix if appropriate
187 ppr_monobind (VarMonoBind name expr)
188 = sep [ppr name <+> equals, nest 4 (pprExpr expr)]
190 ppr_monobind (CoreMonoBind name expr)
191 = sep [ppr name <+> equals, nest 4 (ppr expr)]
193 ppr_monobind (AbsBinds tyvars dictvars exports inlines val_binds)
194 = sep [ptext SLIT("AbsBinds"),
195 brackets (interpp'SP tyvars),
196 brackets (interpp'SP dictvars),
197 brackets (sep (punctuate comma (map ppr exports))),
198 brackets (interpp'SP (nameSetToList inlines))]
200 nest 4 (ppr val_binds)
203 %************************************************************************
205 \subsection{@Sig@: type signatures and value-modifying user pragmas}
207 %************************************************************************
209 It is convenient to lump ``value-modifying'' user-pragmas (e.g.,
210 ``specialise this function to these four types...'') in with type
211 signatures. Then all the machinery to move them into place, etc.,
216 = Sig name -- a bog-std type signature
220 | ClassOpSig name -- Selector name
221 (Maybe name) -- Default-method name (if any)
225 | SpecSig name -- specialise a function or datatype ...
226 (HsType name) -- ... to these types
229 | InlineSig name -- INLINE f
232 | NoInlineSig name -- NOINLINE f
235 | SpecInstSig (HsType name) -- (Class tys); should be a specialisation of the
236 -- current instance decl
239 | FixSig (FixitySig name) -- Fixity declaration
242 data FixitySig name = FixitySig name Fixity SrcLoc
246 sigsForMe :: (name -> Bool) -> [Sig name] -> [Sig name]
248 = filter sig_for_me sigs
250 sig_for_me (Sig n _ _) = f n
251 sig_for_me (ClassOpSig n _ _ _) = f n
252 sig_for_me (SpecSig n _ _) = f n
253 sig_for_me (InlineSig n _) = f n
254 sig_for_me (NoInlineSig n _) = f n
255 sig_for_me (SpecInstSig _ _) = False
256 sig_for_me (FixSig (FixitySig n _ _)) = f n
258 isFixitySig :: Sig name -> Bool
259 isFixitySig (FixSig _) = True
260 isFixitySig _ = False
262 isClassOpSig :: Sig name -> Bool
263 isClassOpSig (ClassOpSig _ _ _ _) = True
264 isClassOpSig _ = False
268 instance (Outputable name) => Outputable (Sig name) where
269 ppr sig = ppr_sig sig
271 instance Outputable name => Outputable (FixitySig name) where
272 ppr (FixitySig name fixity loc) = sep [ppr fixity, ppr name]
275 ppr_sig (Sig var ty _)
276 = sep [ppr var <+> dcolon, nest 4 (ppr ty)]
278 ppr_sig (ClassOpSig var _ ty _)
279 = sep [ppr var <+> dcolon, nest 4 (ppr ty)]
281 ppr_sig (SpecSig var ty _)
282 = sep [ hsep [text "{-# SPECIALIZE", ppr var, dcolon],
283 nest 4 (ppr ty <+> text "#-}")
286 ppr_sig (InlineSig var _)
287 = hsep [text "{-# INLINE", ppr var, text "#-}"]
289 ppr_sig (NoInlineSig var _)
290 = hsep [text "{-# NOINLINE", ppr var, text "#-}"]
292 ppr_sig (SpecInstSig ty _)
293 = hsep [text "{-# SPECIALIZE instance", ppr ty, text "#-}"]
295 ppr_sig (FixSig fix_sig) = ppr fix_sig