Name.lhs 12.8 KB
Newer Older
1
%
2
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
3
4
5
6
7
%
\section[Name]{@Name@: to transmit name info from renamer to typechecker}

\begin{code}
module Name (
8
9
	-- Re-export the OccName stuff
	module OccName,
10

11
12
	-- The Name type
	Name,					-- Abstract
13
	BuiltInSyntax(..), 
14
	mkInternalName, mkSystemName,
15
	mkSystemVarName, mkSysTvName, 
16
	mkFCallName, mkIPName,
17
	mkExternalName, mkWiredInName,
18

19
	nameUnique, setNameUnique,
20
	nameOccName, nameModule, nameModule_maybe,
21
	tidyNameOcc, 
22
	hashName, localiseName,
sof's avatar
sof committed
23

24
	nameSrcLoc, nameParent, nameParent_maybe, isImplicitName, 
25

26
	isSystemName, isInternalName, isExternalName,
27
	isTyVarName, isWiredInName, isBuiltInSyntax,
28
	wiredInNameTyThing_maybe, 
29
	nameIsLocalOrFrom,
30
	
31
32
	-- Class NamedThing and overloaded friends
	NamedThing(..),
33
	getSrcLoc, getOccString
34
    ) where
35

36
37
#include "HsVersions.h"

38
39
import {-# SOURCE #-} TypeRep( TyThing )

40
import OccName		-- All of it
41
import Module		( Module, moduleFS )
42
import SrcLoc		( noSrcLoc, wiredInSrcLoc, SrcLoc )
43
import Unique		( Unique, Uniquable(..), getKey, pprUnique )
44
import Maybes		( orElse, isJust )
45
import FastString	( FastString, zEncodeFS )
46
import Outputable
47
48
\end{code}

49
50
%************************************************************************
%*									*
51
\subsection[Name-datatype]{The @Name@ datatype, and name construction}
52
53
%*									*
%************************************************************************
54
 
55
\begin{code}
56
57
data Name = Name {
		n_sort :: NameSort,	-- What sort of name it is
58
		n_occ  :: !OccName,	-- Its occurrence name
59
		n_uniq :: Unique,
60
		n_loc  :: !SrcLoc	-- Definition site
61
62
	    }

63
64
65
66
-- NOTE: we make the n_loc field strict to eliminate some potential
-- (and real!) space leaks, due to the fact that we don't look at
-- the SrcLoc in a Name all that often.

67
data NameSort
68
69
70
71
72
  = External Module (Maybe Name)
	-- (Just parent) => this Name is a subordinate name of 'parent'
	-- e.g. data constructor of a data type, method of a class
	-- Nothing => not a subordinate
 
73
  | WiredIn Module (Maybe Name) TyThing BuiltInSyntax
74
	-- A variant of External, for wired-in things
75

76
  | Internal		-- A user-defined Id or TyVar
77
78
79
80
			-- defined in the module being compiled

  | System		-- A system-defined Id or TyVar.  Typically the
			-- OccName is very uninformative (like 's')
81
82
83
84
85

data BuiltInSyntax = BuiltInSyntax | UserSyntax
-- BuiltInSyntax is for things like (:), [], tuples etc, 
-- which have special syntactic forms.  They aren't "in scope"
-- as such.
86
87
\end{code}

88
89
Notes about the NameSorts:

90
91
1.  Initially, top-level Ids (including locally-defined ones) get External names, 
    and all other local Ids get Internal names
92

93
2.  Things with a External name are given C static labels, so they finally
94
95
    appear in the .o file's symbol table.  They appear in the symbol table
    in the form M.n.  If originally-local things have this property they
96
    must be made @External@ first.
97

98
99
3.  In the tidy-core phase, a External that is not visible to an importer
    is changed to Internal, and a Internal that is visible is changed to External
100
101

4.  A System Name differs in the following ways:
102
103
104
105
106
107
108
109
110
	a) has unique attached when printing dumps
	b) unifier eliminates sys tyvars in favour of user provs where possible

    Before anything gets printed in interface files or output code, it's
    fed through a 'tidy' processor, which zaps the OccNames to have
    unique names; and converts all sys-locals to user locals
    If any desugarer sys-locals have survived that far, they get changed to
    "ds1", "ds2", etc.

111
112
113
114
115
116
117
118
Built-in syntax => It's a syntactic form, not "in scope" (e.g. [])

Wired-in thing  => The thing (Id, TyCon) is fully known to the compiler, 
		   not read from an interface file. 
		   E.g. Bool, True, Int, Float, and many others

All built-in syntax is for wired-in things.

119
120
121
122
123
124
125
126
127
128
129
130
\begin{code}
nameUnique		:: Name -> Unique
nameOccName		:: Name -> OccName 
nameModule		:: Name -> Module
nameSrcLoc		:: Name -> SrcLoc

nameUnique  name = n_uniq name
nameOccName name = n_occ  name
nameSrcLoc  name = n_loc  name
\end{code}

\begin{code}
131
132
133
134
nameIsLocalOrFrom :: Module -> Name -> Bool
isInternalName	  :: Name -> Bool
isExternalName	  :: Name -> Bool
isSystemName	  :: Name -> Bool
135
136
isWiredInName	  :: Name -> Bool

137
138
isWiredInName (Name {n_sort = WiredIn _ _ _ _}) = True
isWiredInName other			        = False
139

140
wiredInNameTyThing_maybe :: Name -> Maybe TyThing
141
142
wiredInNameTyThing_maybe (Name {n_sort = WiredIn _ _ thing _}) = Just thing
wiredInNameTyThing_maybe other				       = Nothing
143

144
145
146
147
148
149
isBuiltInSyntax (Name {n_sort = WiredIn _ _ _ BuiltInSyntax}) = True
isBuiltInSyntax other			 		      = False

isExternalName (Name {n_sort = External _ _})    = True
isExternalName (Name {n_sort = WiredIn _ _ _ _}) = True
isExternalName other	                         = False
150

151
isInternalName name = not (isExternalName name)
152

153
nameParent_maybe :: Name -> Maybe Name
154
155
156
nameParent_maybe (Name {n_sort = External _ p})    = p
nameParent_maybe (Name {n_sort = WiredIn _ p _ _}) = p
nameParent_maybe other	                           = Nothing
157
158
159
160
161
162

nameParent :: Name -> Name
nameParent name = case nameParent_maybe name of
			Just parent -> parent
			Nothing     -> name

163
164
isImplicitName :: Name -> Bool
-- An Implicit Name is one has a parent; that is, one whose definition
165
-- derives from the parent thing
166
167
isImplicitName name = isJust (nameParent_maybe name)

168
nameModule name = nameModule_maybe name `orElse` pprPanic "nameModule" (ppr name)
169
170
171
nameModule_maybe (Name { n_sort = External mod _})    = Just mod
nameModule_maybe (Name { n_sort = WiredIn mod _ _ _}) = Just mod
nameModule_maybe name				      = Nothing
172

173
174
175
176
nameIsLocalOrFrom from name
  | isExternalName name = from == nameModule name
  | otherwise		= True

177
178
isTyVarName :: Name -> Bool
isTyVarName name = isTvOcc (nameOccName name)
179
180
181
182
183
184
185
186
187
188
189

isSystemName (Name {n_sort = System}) = True
isSystemName other		      = False
\end{code}


%************************************************************************
%*									*
\subsection{Making names}
%*									*
%************************************************************************
190

191
\begin{code}
192
193
mkInternalName :: Unique -> OccName -> SrcLoc -> Name
mkInternalName uniq occ loc = Name { n_uniq = uniq, n_sort = Internal, n_occ = occ, n_loc = loc }
194
195
196
197
198
199
200
201
	-- NB: You might worry that after lots of huffing and
	-- puffing we might end up with two local names with distinct
	-- uniques, but the same OccName.  Indeed we can, but that's ok
	--	* the insides of the compiler don't care: they use the Unique
	--	* when printing for -ddump-xxx you can switch on -dppr-debug to get the
	--	  uniques if you get confused
	--	* for interface files we tidyCore first, which puts the uniques
	--	  into the print name (see setNameVisibility below)
202

203
204
205
206
mkExternalName :: Unique -> Module -> OccName -> Maybe Name -> SrcLoc -> Name
mkExternalName uniq mod occ mb_parent loc 
  = Name { n_uniq = uniq, n_sort = External mod mb_parent,
           n_occ = occ, n_loc = loc }
207

208
209
210
mkWiredInName :: Module -> OccName -> Unique 
	      -> Maybe Name -> TyThing -> BuiltInSyntax -> Name
mkWiredInName mod occ uniq mb_parent thing built_in
211
  = Name { n_uniq = uniq,
212
	   n_sort = WiredIn mod mb_parent thing built_in,
213
	   n_occ = occ, n_loc = wiredInSrcLoc }
214

215
216
217
218
mkSystemName :: Unique -> OccName -> Name
mkSystemName uniq occ = Name { n_uniq = uniq, n_sort = System, 
			       n_occ = occ, n_loc = noSrcLoc }

219
220
mkSystemVarName :: Unique -> FastString -> Name
mkSystemVarName uniq fs = mkSystemName uniq (mkVarOccFS fs)
221

222
223
mkSysTvName :: Unique -> FastString -> Name
mkSysTvName uniq fs = mkSystemName uniq (mkOccNameFS tvName fs) 
224

225
mkFCallName :: Unique -> String -> Name
226
	-- The encoded string completely describes the ccall
227
mkFCallName uniq str =  Name { n_uniq = uniq, n_sort = Internal, 
228
			       n_occ = mkVarOcc str, n_loc = noSrcLoc }
229

230
231
232
mkIPName :: Unique -> OccName -> Name
mkIPName uniq occ
  = Name { n_uniq = uniq,
233
	   n_sort = Internal,
234
	   n_occ  = occ,
235
	   n_loc = noSrcLoc }
236
237
238
\end{code}

\begin{code}
239
240
241
-- When we renumber/rename things, we need to be
-- able to change a Name's Unique to match the cached
-- one in the thing it's the name of.  If you know what I mean.
242
setNameUnique name uniq = name {n_uniq = uniq}
243

244
245
246
247
248
249
tidyNameOcc :: Name -> OccName -> Name
-- We set the OccName of a Name when tidying
-- In doing so, we change System --> Internal, so that when we print
-- it we don't get the unique by default.  It's tidy now!
tidyNameOcc name@(Name { n_sort = System }) occ = name { n_occ = occ, n_sort = Internal}
tidyNameOcc name 			    occ = name { n_occ = occ }
250

251
localiseName :: Name -> Name
252
localiseName n = n { n_sort = Internal }
sof's avatar
sof committed
253
254
255
\end{code}


256
257
258
259
260
261
262
%************************************************************************
%*									*
\subsection{Predicates and selectors}
%*									*
%************************************************************************

\begin{code}
263
hashName :: Name -> Int
264
hashName name = getKey (nameUnique name)
265
266
\end{code}

267

268
269
270
271
272
273
274
%************************************************************************
%*									*
\subsection[Name-instances]{Instance declarations}
%*									*
%************************************************************************

\begin{code}
275
cmpName n1 n2 = n_uniq n1 `compare` n_uniq n2
276
277
278
279
\end{code}

\begin{code}
instance Eq Name where
280
281
    a == b = case (a `compare` b) of { EQ -> True;  _ -> False }
    a /= b = case (a `compare` b) of { EQ -> False; _ -> True }
282
283

instance Ord Name where
284
285
    a <= b = case (a `compare` b) of { LT -> True;  EQ -> True;  GT -> False }
    a <	 b = case (a `compare` b) of { LT -> True;  EQ -> False; GT -> False }
286
287
288
    a >= b = case (a `compare` b) of { LT -> False; EQ -> True;  GT -> True  }
    a >	 b = case (a `compare` b) of { LT -> False; EQ -> False; GT -> True  }
    compare a b = cmpName a b
289

290
instance Uniquable Name where
291
    getUnique = nameUnique
292

293
instance NamedThing Name where
294
    getName n = n
295
296
297
\end{code}


298
299
300
301
302
%************************************************************************
%*									*
\subsection{Pretty printing}
%*									*
%************************************************************************
303
304
305

\begin{code}
instance Outputable Name where
306
307
    ppr name = pprName name

308
309
310
instance OutputableBndr Name where
    pprBndr _ name = pprName name

311
pprName (Name {n_sort = sort, n_uniq = uniq, n_occ = occ})
312
  = getPprStyle $ \ sty ->
313
    case sort of
314
315
316
317
      WiredIn mod _ _ builtin -> pprExternal sty uniq mod occ True  builtin
      External mod _  	      -> pprExternal sty uniq mod occ False UserSyntax
      System   		      -> pprSystem sty uniq occ
      Internal    	      -> pprInternal sty uniq occ
318

319
pprExternal sty uniq mod occ is_wired is_builtin
320
  | codeStyle sty        = ppr_z_module mod <> char '_' <> ppr_z_occ_name occ
321
322
323
	-- In code style, always qualify
	-- ToDo: maybe we could print all wired-in things unqualified
	-- 	 in code style, to reduce symbol table bloat?
324
  | debugStyle sty       = ppr mod <> dot <> ppr_occ_name occ
325
			   <> braces (hsep [if is_wired then ptext SLIT("(w)") else empty,
326
					    pprNameSpaceBrief (occNameSpace occ), 
327
328
		 			    pprUnique uniq])
  | BuiltInSyntax <- is_builtin  = ppr_occ_name occ
329
	-- never qualify builtin syntax
330
331
  | unqualStyle sty mod occ = ppr_occ_name occ
  | otherwise		    = ppr mod <> dot <> ppr_occ_name occ
332

333
pprInternal sty uniq occ
334
  | codeStyle sty  = pprUnique uniq
335
  | debugStyle sty = ppr_occ_name occ <> braces (hsep [pprNameSpaceBrief (occNameSpace occ), 
336
				 		       pprUnique uniq])
337
338
339
  | dumpStyle sty  = ppr_occ_name occ <> char '_' <> pprUnique uniq
			-- For debug dumps, we're not necessarily dumping
			-- tidied code, so we need to print the uniques.
340
  | otherwise      = ppr_occ_name occ	-- User style
341

342
343
-- Like Internal, except that we only omit the unique in Iface style
pprSystem sty uniq occ
344
  | codeStyle sty  = pprUnique uniq
345
  | debugStyle sty = ppr_occ_name occ <> char '_' <> pprUnique uniq
346
		     <> braces (pprNameSpaceBrief (occNameSpace occ))
347
  | otherwise	   = ppr_occ_name occ <> char '_' <> pprUnique uniq
348
349
350
				-- If the tidy phase hasn't run, the OccName
				-- is unlikely to be informative (like 's'),
				-- so print the unique
351

352
ppr_occ_name occ = ftext (occNameFS occ)
353
354
	-- Don't use pprOccName; instead, just print the string of the OccName; 
	-- we print the namespace in the debug stuff above
355
356
357
358
359
360

-- In code style, we Z-encode the strings.  The results of Z-encoding each FastString are
-- cached behind the scenes in the FastString implementation.
ppr_z_occ_name occ = ftext (zEncodeFS (occNameFS occ))
ppr_z_module   mod = ftext (zEncodeFS (moduleFS mod))

361
\end{code}
362

363
364
365
366
367
368
369
370
%************************************************************************
%*									*
\subsection{Overloaded functions related to Names}
%*									*
%************************************************************************

\begin{code}
class NamedThing a where
371
    getOccName :: a -> OccName
372
373
374
    getName    :: a -> Name

    getOccName n = nameOccName (getName n)	-- Default method
375
376
377
378
\end{code}

\begin{code}
getSrcLoc	    :: NamedThing a => a -> SrcLoc
379
getOccString	    :: NamedThing a => a -> String
380

381
getSrcLoc	    = nameSrcLoc	   . getName
382
getOccString 	    = occNameString	   . getOccName
383
384
\end{code}