2 % (c) The AQUA Project, Glasgow University, 1996-1998
4 \section[RdrHsSyn]{Specialisations of the @HsSyn@ syntax for the reader}
6 (Well, really, for specialisations involving @RdrName@s, even if
7 they are used somewhat later on in the compiler...)
46 extractHsTyRdrNames, extractHsTyRdrTyVars,
47 extractHsCtxtRdrTyVars, extractGenericPatTyVars,
49 mkHsOpApp, mkClassDecl, mkClassOpSigDM, mkConDecl,
50 mkHsNegApp, mkNPlusKPat, mkHsIntegral, mkHsFractional,
55 cvValSig, cvClassOpSig, cvInstDeclSig,
59 #include "HsVersions.h"
61 import HsSyn -- Lots of it
62 import OccName ( mkClassTyConOcc, mkClassDataConOcc, mkWorkerOcc,
63 mkSuperDictSelOcc, mkDefaultMethodOcc, mkGenOcc1,
66 import PrelNames ( minusName, negateName, fromIntegerName, fromRationalName )
67 import RdrName ( RdrName, isRdrTyVar, mkRdrUnqual, rdrNameOcc, isRdrTyVar )
69 import BasicTypes ( RecFlag(..) )
70 import Class ( DefMeth (..) )
74 %************************************************************************
76 \subsection{Type synonyms}
78 %************************************************************************
81 type RdrNameArithSeqInfo = ArithSeqInfo RdrName RdrNamePat
82 type RdrNameBangType = BangType RdrName
83 type RdrNameClassOpSig = Sig RdrName
84 type RdrNameConDecl = ConDecl RdrName
85 type RdrNameConDetails = ConDetails RdrName
86 type RdrNameContext = HsContext RdrName
87 type RdrNameHsDecl = HsDecl RdrName RdrNamePat
88 type RdrNameDefaultDecl = DefaultDecl RdrName
89 type RdrNameForeignDecl = ForeignDecl RdrName
90 type RdrNameGRHS = GRHS RdrName RdrNamePat
91 type RdrNameGRHSs = GRHSs RdrName RdrNamePat
92 type RdrNameHsBinds = HsBinds RdrName RdrNamePat
93 type RdrNameHsExpr = HsExpr RdrName RdrNamePat
94 type RdrNameHsModule = HsModule RdrName RdrNamePat
95 type RdrNameIE = IE RdrName
96 type RdrNameImportDecl = ImportDecl RdrName
97 type RdrNameInstDecl = InstDecl RdrName RdrNamePat
98 type RdrNameMatch = Match RdrName RdrNamePat
99 type RdrNameMonoBinds = MonoBinds RdrName RdrNamePat
100 type RdrNamePat = InPat RdrName
101 type RdrNameHsType = HsType RdrName
102 type RdrNameHsTyVar = HsTyVarBndr RdrName
103 type RdrNameSig = Sig RdrName
104 type RdrNameStmt = Stmt RdrName RdrNamePat
105 type RdrNameTyClDecl = TyClDecl RdrName RdrNamePat
107 type RdrNameRuleBndr = RuleBndr RdrName
108 type RdrNameRuleDecl = RuleDecl RdrName RdrNamePat
109 type RdrNameDeprecation = DeprecDecl RdrName
110 type RdrNameFixitySig = FixitySig RdrName
112 type RdrNameHsRecordBinds = HsRecordBinds RdrName RdrNamePat
116 %************************************************************************
118 \subsection{A few functions over HsSyn at RdrName}
120 %************************************************************************
122 @extractHsTyRdrNames@ finds the free variables of a HsType
123 It's used when making the for-alls explicit.
126 extractHsTyRdrNames :: RdrNameHsType -> [RdrName]
127 extractHsTyRdrNames ty = nub (extract_ty ty [])
129 extractHsTyRdrTyVars :: RdrNameHsType -> [RdrName]
130 extractHsTyRdrTyVars ty = nub (filter isRdrTyVar (extract_ty ty []))
132 extractHsCtxtRdrNames :: HsContext RdrName -> [RdrName]
133 extractHsCtxtRdrNames ty = nub (extract_ctxt ty [])
134 extractHsCtxtRdrTyVars :: HsContext RdrName -> [RdrName]
135 extractHsCtxtRdrTyVars ty = filter isRdrTyVar (extractHsCtxtRdrNames ty)
137 extract_ctxt ctxt acc = foldr extract_pred acc ctxt
139 extract_pred (HsClassP cls tys) acc = foldr extract_ty (cls : acc) tys
140 extract_pred (HsIParam n ty) acc = extract_ty ty acc
142 extract_tys tys = foldr extract_ty [] tys
144 extract_ty (HsAppTy ty1 ty2) acc = extract_ty ty1 (extract_ty ty2 acc)
145 extract_ty (HsListTy ty) acc = extract_ty ty acc
146 extract_ty (HsTupleTy _ tys) acc = foldr extract_ty acc tys
147 extract_ty (HsFunTy ty1 ty2) acc = extract_ty ty1 (extract_ty ty2 acc)
148 extract_ty (HsPredTy p) acc = extract_pred p acc
149 extract_ty (HsTyVar tv) acc = tv : acc
150 extract_ty (HsForAllTy Nothing ctxt ty) acc = extract_ctxt ctxt (extract_ty ty acc)
152 extract_ty (HsOpTy ty1 nam ty2) acc = extract_ty ty1 (extract_ty ty2 acc)
153 extract_ty (HsNumTy num) acc = acc
155 extract_ty (HsForAllTy (Just tvs) ctxt ty)
157 (filter (`notElem` locals) $
158 extract_ctxt ctxt (extract_ty ty []))
160 locals = hsTyVarNames tvs
162 extractGenericPatTyVars :: RdrNameMonoBinds -> [RdrName]
163 -- Get the type variables out of the type patterns in a bunch of
164 -- possibly-generic bindings in a class declaration
165 extractGenericPatTyVars binds
166 = filter isRdrTyVar (nub (get binds []))
168 get (AndMonoBinds b1 b2) acc = get b1 (get b2 acc)
169 get (FunMonoBind _ _ ms _) acc = foldr get_m acc ms
172 get_m (Match (TypePatIn ty : _) _ _) acc = extract_ty ty acc
173 get_m other acc = acc
177 %************************************************************************
179 \subsection{Construction functions for Rdr stuff}
181 %************************************************************************
183 mkClassDecl builds a RdrClassDecl, filling in the names for tycon and datacon
184 by deriving them from the name of the class. We fill in the names for the
185 tycon and datacon corresponding to the class, by deriving them from the
186 name of the class itself. This saves recording the names in the interface
187 file (which would be equally good).
189 Similarly for mkConDecl, mkClassOpSig and default-method names.
191 *** See "THE NAMING STORY" in HsDecls ****
194 mkClassDecl cxt cname tyvars fds sigs mbinds loc
195 = ClassDecl { tcdCtxt = cxt, tcdName = cname, tcdTyVars = tyvars,
196 tcdFDs = fds, tcdSigs = sigs, tcdMeths = mbinds,
197 tcdSysNames = new_names, tcdLoc = loc }
199 cls_occ = rdrNameOcc cname
200 data_occ = mkClassDataConOcc cls_occ
201 dname = mkRdrUnqual data_occ
202 dwname = mkRdrUnqual (mkWorkerOcc data_occ)
203 tname = mkRdrUnqual (mkClassTyConOcc cls_occ)
204 sc_sel_names = [ mkRdrUnqual (mkSuperDictSelOcc n cls_occ)
205 | n <- [1..length cxt]]
206 -- We number off the superclass selectors, 1, 2, 3 etc so that we
207 -- can construct names for the selectors. Thus
208 -- class (C a, C b) => D a b where ...
209 -- gives superclass selectors
211 -- (We used to call them D_C, but now we can have two different
212 -- superclasses both called C!)
213 new_names = mkClassDeclSysNames (tname, dname, dwname, sc_sel_names)
215 mkTyData new_or_data context tname list_var list_con i maybe src
216 = let t_occ = rdrNameOcc tname
217 name1 = mkRdrUnqual (mkGenOcc1 t_occ)
218 name2 = mkRdrUnqual (mkGenOcc2 t_occ)
219 in TyData { tcdND = new_or_data, tcdCtxt = context, tcdName = tname,
220 tcdTyVars = list_var, tcdCons = list_con, tcdNCons = i,
221 tcdDerivs = maybe, tcdLoc = src, tcdSysNames = [name1, name2] }
223 mkClassOpSigDM op ty loc
224 = ClassOpSig op (DefMeth dm_rn) ty loc
226 dm_rn = mkRdrUnqual (mkDefaultMethodOcc (rdrNameOcc op))
228 mkConDecl cname ex_vars cxt details loc
229 = ConDecl cname wkr_name ex_vars cxt details loc
231 wkr_name = mkRdrUnqual (mkWorkerOcc (rdrNameOcc cname))
235 mkHsNegApp :: RdrNameHsExpr -> RdrNameHsExpr
236 -- If the type checker sees (negate 3#) it will barf, because negate
237 -- can't take an unboxed arg. But that is exactly what it will see when
238 -- we write "-3#". So we have to do the negation right now!
240 -- We also do the same service for boxed literals, because this function
241 -- is also used for patterns (which, remember, are parsed as expressions)
242 -- and pattern don't have negation in them.
244 -- Finally, it's important to represent minBound as minBound, and not
245 -- as (negate (-minBound)), becuase the latter is out of range.
247 mkHsNegApp (HsLit (HsIntPrim i)) = HsLit (HsIntPrim (-i))
248 mkHsNegApp (HsLit (HsFloatPrim i)) = HsLit (HsFloatPrim (-i))
249 mkHsNegApp (HsLit (HsDoublePrim i)) = HsLit (HsDoublePrim (-i))
251 mkHsNegApp (HsOverLit (HsIntegral i n)) = HsOverLit (HsIntegral (-i) n)
252 mkHsNegApp (HsOverLit (HsFractional f n)) = HsOverLit (HsFractional (-f) n)
253 mkHsNegApp expr = NegApp expr negateName
256 A useful function for building @OpApps@. The operator is always a
257 variable, and we don't know the fixity yet.
260 mkHsOpApp e1 op e2 = OpApp e1 (HsVar op) (error "mkOpApp:fixity") e2
263 These are the bits of syntax that contain rebindable names
264 See RnEnv.lookupSyntaxName
267 mkHsIntegral i = HsIntegral i fromIntegerName
268 mkHsFractional f = HsFractional f fromRationalName
269 mkNPlusKPat n k = NPlusKPatIn n k minusName
273 %************************************************************************
275 \subsection[rdrBinding]{Bindings straight out of the parser}
277 %************************************************************************
281 = -- On input we use the Empty/And form rather than a list
283 | RdrAndBindings RdrBinding RdrBinding
285 -- Value bindings havn't been united with their
287 | RdrValBinding RdrNameMonoBinds
289 -- Signatures are mysterious; we can't
290 -- tell if its a Sig or a ClassOpSig,
291 -- so we just save the pieces:
294 -- The remainder all fit into the main HsDecl form
295 | RdrHsDecl RdrNameHsDecl
297 type SigConverter = RdrNameSig -> RdrNameSig
304 (Maybe RdrNameHsType)
308 %************************************************************************
310 \subsection[cvDecls]{Convert various top-level declarations}
312 %************************************************************************
314 We make a point not to throw any user-pragma ``sigs'' at
315 these conversion functions:
318 cvValSig, cvClassOpSig, cvInstDeclSig :: SigConverter
322 cvInstDeclSig sig = sig
324 cvClassOpSig (Sig var poly_ty src_loc) = mkClassOpSigDM var poly_ty src_loc
325 cvClassOpSig sig = sig
329 %************************************************************************
331 \subsection[cvBinds-etc]{Converting to @HsBinds@, @MonoBinds@, etc.}
333 %************************************************************************
335 Function definitions are restructured here. Each is assumed to be recursive
336 initially, and non recursive definitions are discovered by the dependency
340 cvBinds :: SigConverter -> RdrBinding -> RdrNameHsBinds
341 -- The mysterious SigConverter converts Sigs to ClassOpSigs
342 -- in class declarations. Mostly it's just an identity function
344 cvBinds sig_cvtr binding
345 = case (cvMonoBindsAndSigs sig_cvtr binding) of { (mbs, sigs) ->
346 MonoBind mbs sigs Recursive
351 cvMonoBindsAndSigs :: SigConverter
353 -> (RdrNameMonoBinds, [RdrNameSig])
355 cvMonoBindsAndSigs sig_cvtr fb
356 = mangle_bind (EmptyMonoBinds, []) fb
358 mangle_bind acc RdrNullBind
361 mangle_bind acc (RdrAndBindings fb1 fb2)
362 = mangle_bind (mangle_bind acc fb1) fb2
364 mangle_bind (b_acc, s_acc) (RdrSig sig)
365 = (b_acc, sig_cvtr sig : s_acc)
367 mangle_bind (b_acc, s_acc) (RdrValBinding binding)
368 = (b_acc `AndMonoBinds` binding, s_acc)
372 %************************************************************************
374 \subsection[PrefixToHS-utils]{Utilities for conversion}
376 %************************************************************************
378 Separate declarations into all the various kinds:
381 cvTopDecls :: RdrBinding -> [RdrNameHsDecl]
384 (top_decls, mono_binds, sigs) = go ([], EmptyMonoBinds, []) bind
386 (ValD (MonoBind mono_binds sigs Recursive) : top_decls)
388 go acc RdrNullBind = acc
389 go acc (RdrAndBindings b1 b2) = go (go acc b1) b2
390 go (topds, mbs, sigs) (RdrHsDecl d) = (d : topds, mbs, sigs)
391 go (topds, mbs, sigs) (RdrSig (FixSig d)) = (FixD d : topds, mbs, sigs)
392 go (topds, mbs, sigs) (RdrSig sig) = (topds, mbs, sig:sigs)
393 go (topds, mbs, sigs) (RdrValBinding bind) = (topds, mbs `AndMonoBinds` bind, sigs)