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...)
47 extractHsTyRdrTyVars, extractHsTysRdrTyVars,
49 extractRuleBndrsTyVars,
50 extractHsCtxtRdrTyVars, extractGenericPatTyVars,
52 mkHsOpApp, mkClassDecl, mkClassOpSig, mkConDecl,
58 cvValSig, cvClassOpSig, cvInstDeclSig,
62 #include "HsVersions.h"
64 import HsSyn -- Lots of it
65 import HsPat ( collectSigTysFromPats )
66 import OccName ( mkClassTyConOcc, mkClassDataConOcc, mkWorkerOcc,
67 mkSuperDictSelOcc, mkDefaultMethodOcc, mkGenOcc1,
70 import PrelNames ( negate_RDR )
71 import RdrName ( RdrName, isRdrTyVar, mkRdrUnqual, rdrNameOcc,
74 import BasicTypes ( RecFlag(..) )
75 import Class ( DefMeth (..) )
79 %************************************************************************
81 \subsection{Type synonyms}
83 %************************************************************************
86 type RdrNameArithSeqInfo = ArithSeqInfo RdrName RdrNamePat
87 type RdrNameBangType = BangType RdrName
88 type RdrNameClassOpSig = Sig RdrName
89 type RdrNameConDecl = ConDecl RdrName
90 type RdrNameConDetails = ConDetails RdrName
91 type RdrNameContext = HsContext RdrName
92 type RdrNameHsDecl = HsDecl RdrName RdrNamePat
93 type RdrNameDefaultDecl = DefaultDecl RdrName
94 type RdrNameForeignDecl = ForeignDecl RdrName
95 type RdrNameGRHS = GRHS RdrName RdrNamePat
96 type RdrNameGRHSs = GRHSs RdrName RdrNamePat
97 type RdrNameHsBinds = HsBinds RdrName RdrNamePat
98 type RdrNameHsExpr = HsExpr RdrName RdrNamePat
99 type RdrNameHsModule = HsModule RdrName RdrNamePat
100 type RdrNameIE = IE RdrName
101 type RdrNameImportDecl = ImportDecl RdrName
102 type RdrNameInstDecl = InstDecl RdrName RdrNamePat
103 type RdrNameMatch = Match RdrName RdrNamePat
104 type RdrNameMonoBinds = MonoBinds RdrName RdrNamePat
105 type RdrNamePat = InPat RdrName
106 type RdrNameHsType = HsType RdrName
107 type RdrNameHsTyVar = HsTyVarBndr RdrName
108 type RdrNameSig = Sig RdrName
109 type RdrNameStmt = Stmt RdrName RdrNamePat
110 type RdrNameTyClDecl = TyClDecl RdrName RdrNamePat
111 type RdrNameRuleBndr = RuleBndr RdrName
112 type RdrNameRuleDecl = RuleDecl RdrName RdrNamePat
113 type RdrNameDeprecation = DeprecDecl RdrName
114 type RdrNameFixitySig = FixitySig RdrName
116 type RdrNameHsRecordBinds = HsRecordBinds RdrName RdrNamePat
120 %************************************************************************
122 \subsection{A few functions over HsSyn at RdrName}
124 %************************************************************************
126 @extractHsTyRdrNames@ finds the free variables of a HsType
127 It's used when making the for-alls explicit.
130 extractHsTyRdrNames :: HsType RdrName -> [RdrName]
131 extractHsTyRdrNames ty = nub (extract_ty ty [])
133 extractHsTyRdrTyVars :: RdrNameHsType -> [RdrName]
134 extractHsTyRdrTyVars ty = filter isRdrTyVar (extractHsTyRdrNames ty)
136 extractHsTysRdrTyVars :: [RdrNameHsType] -> [RdrName]
137 extractHsTysRdrTyVars tys = filter isRdrTyVar (nub (extract_tys tys))
139 extractRuleBndrsTyVars :: [RuleBndr RdrName] -> [RdrName]
140 extractRuleBndrsTyVars bndrs = filter isRdrTyVar (nub (foldr go [] bndrs))
142 go (RuleBndr _) acc = acc
143 go (RuleBndrSig _ ty) acc = extract_ty ty acc
145 extractHsCtxtRdrNames :: HsContext RdrName -> [RdrName]
146 extractHsCtxtRdrNames ty = nub (extract_ctxt ty [])
147 extractHsCtxtRdrTyVars :: HsContext RdrName -> [RdrName]
148 extractHsCtxtRdrTyVars ty = filter isRdrTyVar (extractHsCtxtRdrNames ty)
150 extract_ctxt ctxt acc = foldr extract_pred acc ctxt
152 extract_pred (HsPClass cls tys) acc = foldr extract_ty (cls : acc) tys
153 extract_pred (HsPIParam n ty) acc = extract_ty ty acc
155 extract_tys tys = foldr extract_ty [] tys
157 extract_ty (HsAppTy ty1 ty2) acc = extract_ty ty1 (extract_ty ty2 acc)
158 extract_ty (HsListTy ty) acc = extract_ty ty acc
159 extract_ty (HsTupleTy _ tys) acc = foldr extract_ty acc tys
160 extract_ty (HsFunTy ty1 ty2) acc = extract_ty ty1 (extract_ty ty2 acc)
161 extract_ty (HsPredTy p) acc = extract_pred p acc
162 extract_ty (HsUsgTy usg ty) acc = extract_ty ty acc
163 extract_ty (HsUsgForAllTy uv ty) acc = extract_ty ty acc
164 extract_ty (HsTyVar tv) acc = tv : acc
165 extract_ty (HsForAllTy Nothing ctxt ty) acc = extract_ctxt ctxt (extract_ty ty acc)
167 extract_ty (HsOpTy ty1 nam ty2) acc = extract_ty ty1 (extract_ty ty2 acc)
168 extract_ty (HsNumTy num) acc = acc
170 extract_ty (HsForAllTy (Just tvs) ctxt ty)
172 (filter (`notElem` locals) $
173 extract_ctxt ctxt (extract_ty ty []))
175 locals = hsTyVarNames tvs
178 extractPatsTyVars :: [RdrNamePat] -> [RdrName]
179 extractPatsTyVars = filter isRdrTyVar .
182 collectSigTysFromPats
184 extractGenericPatTyVars :: RdrNameMonoBinds -> [RdrName]
185 -- Get the type variables out of the type patterns in a bunch of
186 -- possibly-generic bindings in a class declaration
187 extractGenericPatTyVars binds
188 = filter isRdrTyVar (nub (get binds []))
190 get (AndMonoBinds b1 b2) acc = get b1 (get b2 acc)
191 get (FunMonoBind _ _ ms _) acc = foldr get_m acc ms
194 get_m (Match _ (TypePatIn ty : _) _ _) acc = extract_ty ty acc
195 get_m other acc = acc
199 %************************************************************************
201 \subsection{Construction functions for Rdr stuff}
203 %************************************************************************
205 mkClassDecl builds a RdrClassDecl, filling in the names for tycon and datacon
206 by deriving them from the name of the class. We fill in the names for the
207 tycon and datacon corresponding to the class, by deriving them from the
208 name of the class itself. This saves recording the names in the interface
209 file (which would be equally good).
211 Similarly for mkConDecl, mkClassOpSig and default-method names.
214 mkClassDecl cxt cname tyvars fds sigs mbinds loc
215 = ClassDecl cxt cname tyvars fds sigs mbinds new_names loc
217 cls_occ = rdrNameOcc cname
218 data_occ = mkClassDataConOcc cls_occ
219 dname = mkRdrUnqual data_occ
220 dwname = mkRdrUnqual (mkWorkerOcc data_occ)
221 tname = mkRdrUnqual (mkClassTyConOcc cls_occ)
222 sc_sel_names = [ mkRdrUnqual (mkSuperDictSelOcc n cls_occ)
223 | n <- [1..length cxt]]
224 -- We number off the superclass selectors, 1, 2, 3 etc so that we
225 -- can construct names for the selectors. Thus
226 -- class (C a, C b) => D a b where ...
227 -- gives superclass selectors
229 -- (We used to call them D_C, but now we can have two different
230 -- superclasses both called C!)
231 new_names = mkClassDeclSysNames (tname, dname, dwname, sc_sel_names)
234 mkTyData new_or_data context tname list_var list_con i maybe src
235 = let t_occ = rdrNameOcc tname
236 name1 = mkRdrUnqual (mkGenOcc1 t_occ)
237 name2 = mkRdrUnqual (mkGenOcc2 t_occ)
238 in TyData new_or_data context
239 tname list_var list_con i maybe src name1 name2
241 mkClassOpSig (DefMeth x) op ty loc
242 = ClassOpSig op (Just (DefMeth dm_rn)) ty loc
244 dm_rn = mkRdrUnqual (mkDefaultMethodOcc (rdrNameOcc op))
245 mkClassOpSig x op ty loc =
246 ClassOpSig op (Just x) ty loc
248 mkConDecl cname ex_vars cxt details loc
249 = ConDecl cname wkr_name ex_vars cxt details loc
251 wkr_name = mkRdrUnqual (mkWorkerOcc (rdrNameOcc cname))
255 mkHsNegApp :: RdrNameHsExpr -> RdrNameHsExpr
256 -- If the type checker sees (negate 3#) it will barf, because negate
257 -- can't take an unboxed arg. But that is exactly what it will see when
258 -- we write "-3#". So we have to do the negation right now!
260 -- We also do the same service for boxed literals, because this function
261 -- is also used for patterns (which, remember, are parsed as expressions)
262 -- and pattern don't have negation in them.
264 -- Finally, it's important to represent minBound as minBound, and not
265 -- as (negate (-minBound)), becuase the latter is out of range.
267 mkHsNegApp (HsLit (HsIntPrim i)) = HsLit (HsIntPrim (-i))
268 mkHsNegApp (HsLit (HsFloatPrim i)) = HsLit (HsFloatPrim (-i))
269 mkHsNegApp (HsLit (HsDoublePrim i)) = HsLit (HsDoublePrim (-i))
271 mkHsNegApp (HsOverLit (HsIntegral i n)) = HsOverLit (HsIntegral (-i) n)
272 mkHsNegApp (HsOverLit (HsFractional f n)) = HsOverLit (HsFractional (-f) n)
273 mkHsNegApp expr = NegApp expr negate_RDR
276 A useful function for building @OpApps@. The operator is always a
277 variable, and we don't know the fixity yet.
280 mkHsOpApp e1 op e2 = OpApp e1 (HsVar op) (error "mkOpApp:fixity") e2
284 %************************************************************************
286 \subsection[rdrBinding]{Bindings straight out of the parser}
288 %************************************************************************
292 = -- On input we use the Empty/And form rather than a list
294 | RdrAndBindings RdrBinding RdrBinding
296 -- Value bindings havn't been united with their
298 | RdrValBinding RdrNameMonoBinds
300 -- Signatures are mysterious; we can't
301 -- tell if its a Sig or a ClassOpSig,
302 -- so we just save the pieces:
305 -- The remainder all fit into the main HsDecl form
306 | RdrHsDecl RdrNameHsDecl
308 type SigConverter = RdrNameSig -> RdrNameSig
315 (Maybe RdrNameHsType)
319 %************************************************************************
321 \subsection[cvDecls]{Convert various top-level declarations}
323 %************************************************************************
325 We make a point not to throw any user-pragma ``sigs'' at
326 these conversion functions:
329 cvValSig, cvClassOpSig, cvInstDeclSig :: SigConverter
333 cvInstDeclSig sig = sig
335 cvClassOpSig (Sig var poly_ty src_loc) = ClassOpSig var Nothing poly_ty src_loc
336 cvClassOpSig sig = sig
340 %************************************************************************
342 \subsection[cvBinds-etc]{Converting to @HsBinds@, @MonoBinds@, etc.}
344 %************************************************************************
346 Function definitions are restructured here. Each is assumed to be recursive
347 initially, and non recursive definitions are discovered by the dependency
351 cvBinds :: SigConverter -> RdrBinding -> RdrNameHsBinds
352 -- The mysterious SigConverter converts Sigs to ClassOpSigs
353 -- in class declarations. Mostly it's just an identity function
355 cvBinds sig_cvtr binding
356 = case (cvMonoBindsAndSigs sig_cvtr binding) of { (mbs, sigs) ->
357 MonoBind mbs sigs Recursive
362 cvMonoBindsAndSigs :: SigConverter
364 -> (RdrNameMonoBinds, [RdrNameSig])
366 cvMonoBindsAndSigs sig_cvtr fb
367 = mangle_bind (EmptyMonoBinds, []) fb
369 mangle_bind acc RdrNullBind
372 mangle_bind acc (RdrAndBindings fb1 fb2)
373 = mangle_bind (mangle_bind acc fb1) fb2
375 mangle_bind (b_acc, s_acc) (RdrSig sig)
376 = (b_acc, sig_cvtr sig : s_acc)
378 mangle_bind (b_acc, s_acc) (RdrValBinding binding)
379 = (b_acc `AndMonoBinds` binding, s_acc)
383 %************************************************************************
385 \subsection[PrefixToHS-utils]{Utilities for conversion}
387 %************************************************************************
389 Separate declarations into all the various kinds:
392 cvTopDecls :: RdrBinding -> [RdrNameHsDecl]
395 (top_decls, mono_binds, sigs) = go ([], EmptyMonoBinds, []) bind
397 (ValD (MonoBind mono_binds sigs Recursive) : top_decls)
399 go acc RdrNullBind = acc
400 go acc (RdrAndBindings b1 b2) = go (go acc b1) b2
401 go (topds, mbs, sigs) (RdrHsDecl d) = (d : topds, mbs, sigs)
402 go (topds, mbs, sigs) (RdrSig (FixSig d)) = (FixD d : topds, mbs, sigs)
403 go (topds, mbs, sigs) (RdrSig sig) = (topds, mbs, sig:sigs)
404 go (topds, mbs, sigs) (RdrValBinding bind) = (topds, mbs `AndMonoBinds` bind, sigs)