HsDecls.lhs 29.9 KB
Newer Older
1
%
2
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
3 4 5
%
\section[HsDecls]{Abstract syntax: global declarations}

6
Definitions for: @TyDecl@ and @oCnDecl@, @ClassDecl@,
sof's avatar
sof committed
7
@InstDecl@, @DefaultDecl@ and @ForeignDecl@.
8 9

\begin{code}
10
module HsDecls (
11
	HsDecl(..), TyClDecl(..), InstDecl(..), RuleDecl(..), RuleBndr(..),
12
	DefaultDecl(..), 
chak's avatar
chak committed
13 14
	ForeignDecl(..), ForeignImport(..), ForeignExport(..),
	CImportSpec(..), FoType(..),
15
	ConDecl(..), CoreDecl(..),
16
	BangType(..), getBangType, getBangStrictness, unbangedType,
17
	DeprecDecl(..), DeprecTxt,
18
	hsDeclName, instDeclName, 
19 20
	tyClDeclName, tyClDeclNames, tyClDeclTyVars,
	isClassDecl, isSynDecl, isDataDecl, isIfaceSigDecl, 
21
	isTypeOrClassDecl, countTyClDecls,
22 23 24
	isSourceInstDecl, ifaceRuleDeclName,
	conDetailsTys,
	collectRuleBndrSigTys, isSrcRule
25
    ) where
26

27
#include "HsVersions.h"
28 29

-- friends:
30 31 32 33 34 35
import {-# SOURCE #-}	HsExpr( HsExpr, pprExpr )
	-- Because Expr imports Decls via HsBracket

import HsBinds		( HsBinds, MonoBinds, Sig(..) )
import HsPat		( HsConDetails(..), hsConArgs )
import HsImpExp		( pprHsVar )
36
import HsTypes
37
import PprCore		( pprCoreRule )
38 39
import HsCore		( UfExpr, UfBinder, HsIdInfo, pprHsIdInfo,
			  eq_ufBinders, eq_ufExpr, pprUfExpr 
40
			)
41
import CoreSyn		( CoreRule(..), RuleName )
42
import BasicTypes	( NewOrData(..), StrictnessMark(..), Activation(..), FixitySig(..) )
chak's avatar
chak committed
43 44
import ForeignCall	( CCallTarget(..), DNCallSpec, CCallConv, Safety,
			  CExportSpec(..)) 
45 46

-- others:
47
import Name		( NamedThing )
48
import FunDeps		( pprFundeps )
49
import TyCon		( DataConDetails(..), visibleDataCons )
50
import Class		( FunDep, DefMeth(..) )
51
import CStrings		( CLabelString )
52
import Outputable	
sof's avatar
sof committed
53
import Util		( eqListBy, count )
54
import SrcLoc		( SrcLoc )
rrt's avatar
rrt committed
55
import FastString
56

57
import Maybe		( isNothing, fromJust )	
58 59
\end{code}

60 61 62 63 64 65 66 67

%************************************************************************
%*									*
\subsection[HsDecl]{Declarations}
%*									*
%************************************************************************

\begin{code}
68 69 70 71 72 73 74 75 76 77 78
data HsDecl id
  = TyClD	(TyClDecl id)
  | InstD	(InstDecl  id)
  | DefD	(DefaultDecl id)
  | ValD	(HsBinds id)
  | ForD        (ForeignDecl id)
  | FixD	(FixitySig id)
  | DeprecD	(DeprecDecl id)
  | RuleD	(RuleDecl id)
  | CoreD	(CoreDecl id)
  | SpliceD	(HsExpr id)	-- Top level splice
79 80 81 82 83 84 85 86 87 88 89 90 91

-- NB: all top-level fixity decls are contained EITHER
-- EITHER FixDs
-- OR     in the ClassDecls in TyClDs
--
-- The former covers
-- 	a) data constructors
-- 	b) class methods (but they can be also done in the
-- 		signatures of class decls)
--	c) imported functions (that have an IfacSig)
--	d) top level decls
--
-- The latter is for class methods only
92 93 94
\end{code}

\begin{code}
sof's avatar
sof committed
95
#ifdef DEBUG
96 97
hsDeclName :: (NamedThing name, OutputableBndr name)
	   => HsDecl name -> name
sof's avatar
sof committed
98
#endif
99 100 101 102 103
hsDeclName (TyClD decl)			 = tyClDeclName     decl
hsDeclName (InstD decl)		         = instDeclName     decl
hsDeclName (ForD  decl)		         = foreignDeclName decl
hsDeclName (FixD  (FixitySig name _ _))  = name
hsDeclName (CoreD (CoreDecl name _ _ _)) = name
104
-- Others don't make sense
sof's avatar
sof committed
105
#ifdef DEBUG
chak's avatar
chak committed
106
hsDeclName x				= pprPanic "HsDecls.hsDeclName" (ppr x)
sof's avatar
sof committed
107
#endif
108

109

110
instDeclName :: InstDecl name -> name
111
instDeclName (InstDecl _ _ _ (Just name) _) = name
112

113 114 115
\end{code}

\begin{code}
116
instance OutputableBndr name => Outputable (HsDecl name) where
117

118
    ppr (TyClD dcl)  = ppr dcl
119 120 121
    ppr (ValD binds) = ppr binds
    ppr (DefD def)   = ppr def
    ppr (InstD inst) = ppr inst
sof's avatar
sof committed
122
    ppr (ForD fd)    = ppr fd
123
    ppr (FixD fd)    = ppr fd
124
    ppr (RuleD rd)   = ppr rd
125
    ppr (DeprecD dd) = ppr dd
126 127
    ppr (CoreD dd)   = ppr dd
    ppr (SpliceD e)  = ptext SLIT("splice") <> parens (pprExpr e)
128 129
\end{code}

130

131 132 133 134 135 136
%************************************************************************
%*									*
\subsection[TyDecl]{@data@, @newtype@ or @type@ (synonym) type declaration}
%*									*
%************************************************************************

137 138 139
		--------------------------------
			THE NAMING STORY
		--------------------------------
140

141 142 143 144 145
Here is the story about the implicit names that go with type, class, and instance
decls.  It's a bit tricky, so pay attention!

"Implicit" (or "system") binders
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164
  Each data type decl defines 
	a worker name for each constructor
	to-T and from-T convertors
  Each class decl defines
	a tycon for the class
	a data constructor for that tycon
	the worker for that constructor
	a selector for each superclass

All have occurrence names that are derived uniquely from their parent declaration.

None of these get separate definitions in an interface file; they are
fully defined by the data or class decl.  But they may *occur* in
interface files, of course.  Any such occurrence must haul in the
relevant type or class decl.

Plan of attack:
 - Ensure they "point to" the parent data/class decl 
   when loading that decl from an interface file
165 166 167 168 169
   (See RnHiFiles.getSysBinders)

 - When typechecking the decl, we build the implicit TyCons and Ids.
   When doing so we look them up in the name cache (RnEnv.lookupSysName),
   to ensure correct module and provenance is set
170

171 172
These are the two places that we have to conjure up the magic derived
names.  (The actual magic is in OccName.mkWorkerOcc, etc.)
173

174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249
Default methods
~~~~~~~~~~~~~~~
 - Occurrence name is derived uniquely from the method name
   E.g. $dmmax

 - If there is a default method name at all, it's recorded in
   the ClassOpSig (in HsBinds), in the DefMeth field.
   (DefMeth is defined in Class.lhs)

Source-code class decls and interface-code class decls are treated subtly
differently, which has given me a great deal of confusion over the years.
Here's the deal.  (We distinguish the two cases because source-code decls
have (Just binds) in the tcdMeths field, whereas interface decls have Nothing.

In *source-code* class declarations:
 - When parsing, every ClassOpSig gets a DefMeth with a suitable RdrName
   This is done by RdrHsSyn.mkClassOpSigDM

 - The renamer renames it to a Name

 - During typechecking, we generate a binding for each $dm for 
   which there's a programmer-supplied default method:
	class Foo a where
	  op1 :: <type>
	  op2 :: <type>
	  op1 = ...
   We generate a binding for $dmop1 but not for $dmop2.
   The Class for Foo has a NoDefMeth for op2 and a DefMeth for op1.
   The Name for $dmop2 is simply discarded.

In *interface-file* class declarations:
  - When parsing, we see if there's an explicit programmer-supplied default method
    because there's an '=' sign to indicate it:
	class Foo a where
	  op1 = :: <type>	-- NB the '='
  	  op2   :: <type>
    We use this info to generate a DefMeth with a suitable RdrName for op1,
    and a NoDefMeth for op2
  - The interface file has a separate definition for $dmop1, with unfolding etc.
  - The renamer renames it to a Name.
  - The renamer treats $dmop1 as a free variable of the declaration, so that
    the binding for $dmop1 will be sucked in.  (See RnHsSyn.tyClDeclFVs)  
    This doesn't happen for source code class decls, because they *bind* the default method.

Dictionary functions
~~~~~~~~~~~~~~~~~~~~
Each instance declaration gives rise to one dictionary function binding.

The type checker makes up new source-code instance declarations
(e.g. from 'deriving' or generic default methods --- see
TcInstDcls.tcInstDecls1).  So we can't generate the names for
dictionary functions in advance (we don't know how many we need).

On the other hand for interface-file instance declarations, the decl
specifies the name of the dictionary function, and it has a binding elsewhere
in the interface file:
	instance {Eq Int} = dEqInt
	dEqInt :: {Eq Int} <pragma info>

So again we treat source code and interface file code slightly differently.

Source code:
  - Source code instance decls have a Nothing in the (Maybe name) field
    (see data InstDecl below)

  - The typechecker makes up a Local name for the dict fun for any source-code
    instance decl, whether it comes from a source-code instance decl, or whether
    the instance decl is derived from some other construct (e.g. 'deriving').

  - The occurrence name it chooses is derived from the instance decl (just for 
    documentation really) --- e.g. dNumInt.  Two dict funs may share a common
    occurrence name, but will have different uniques.  E.g.
	instance Foo [Int]  where ...
	instance Foo [Bool] where ...
    These might both be dFooList

250
  - The CoreTidy phase externalises the name, and ensures the occurrence name is
251 252 253 254 255 256 257 258 259 260 261 262
    unique (this isn't special to dict funs).  So we'd get dFooList and dFooList1.

  - We can take this relaxed approach (changing the occurrence name later) 
    because dict fun Ids are not captured in a TyCon or Class (unlike default
    methods, say).  Instead, they are kept separately in the InstEnv.  This
    makes it easy to adjust them after compiling a module.  (Once we've finished
    compiling that module, they don't change any more.)


Interface file code:
  - The instance decl gives the dict fun name, so the InstDecl has a (Just name)
    in the (Maybe name) field.
263

264 265
  - RnHsSyn.instDeclFVs treats the dict fun name as free in the decl, so that we
    suck in the dfun binding
266 267


268
\begin{code}
269 270 271 272 273
-- TyClDecls are precisely the kind of declarations that can 
-- appear in interface files; or (internally) in GHC's interface
-- for a module.  That's why (despite the misnomer) IfaceSig and ForeignType
-- are both in TyClDecl

274
data TyClDecl name
275
  = IfaceSig {	tcdName :: name,		-- It may seem odd to classify an interface-file signature
276 277
		tcdType :: HsType name,		-- as a 'TyClDecl', but it's very convenient.  
		tcdIdInfo :: [HsIdInfo name],
278 279 280
		tcdLoc :: SrcLoc
    }

rrt's avatar
rrt committed
281 282 283 284
  | ForeignType { tcdName    :: name,		-- See remarks about IfaceSig above
		  tcdExtName :: Maybe FastString,
		  tcdFoType  :: FoType,
		  tcdLoc     :: SrcLoc }
285

286
  | TyData {	tcdND     :: NewOrData,
287 288 289 290 291
		tcdCtxt   :: HsContext name,	 -- Context
		tcdName   :: name,		 -- Type constructor
		tcdTyVars :: [HsTyVarBndr name], -- Type variables
		tcdCons	  :: DataConDetails (ConDecl name),	 -- Data constructors
		tcdDerivs :: Maybe (HsContext name),	-- Derivings; Nothing => not specified
292
							-- Just [] => derive exactly what is asked
293 294 295 296 297 298 299
		tcdGeneric :: Maybe Bool,	-- Nothing <=> source decl
						-- Just x  <=> interface-file decl;
						-- 	x=True <=> generic converter functions available
						-- We need this for imported data decls, since the
						-- imported modules may have been compiled with
						-- different flags to the current compilation unit
		tcdLoc	   :: SrcLoc
300 301 302 303 304 305 306 307 308 309 310 311 312
    }

  | TySynonym {	tcdName :: name,		        -- type constructor
		tcdTyVars :: [HsTyVarBndr name],	-- type variables
		tcdSynRhs :: HsType name,	        -- synonym expansion
		tcdLoc    :: SrcLoc
    }

  | ClassDecl {	tcdCtxt    :: HsContext name, 	 	-- Context...
		tcdName    :: name,		    	-- Name of the class
		tcdTyVars  :: [HsTyVarBndr name],	-- The class type variables
		tcdFDs     :: [FunDep name],		-- Functional dependencies
		tcdSigs    :: [Sig name],		-- Methods' signatures
313 314 315
		tcdMeths   :: Maybe (MonoBinds name),	-- Default methods
							-- 	Nothing for imported class decls
							-- 	Just bs for source   class decls
316 317
		tcdLoc      :: SrcLoc
    }
318 319 320 321 322
\end{code}

Simple classifiers

\begin{code}
323
isIfaceSigDecl, isDataDecl, isSynDecl, isClassDecl :: TyClDecl name -> Bool
324

325 326
isIfaceSigDecl (IfaceSig {}) = True
isIfaceSigDecl other	     = False
327

328 329
isSynDecl (TySynonym {}) = True
isSynDecl other		 = False
330

331 332
isDataDecl (TyData {}) = True
isDataDecl other       = False
333

334 335
isClassDecl (ClassDecl {}) = True
isClassDecl other	   = False
sof's avatar
sof committed
336

337 338 339 340 341
isTypeOrClassDecl (ClassDecl   {}) = True
isTypeOrClassDecl (TyData      {}) = True
isTypeOrClassDecl (TySynonym   {}) = True
isTypeOrClassDecl (ForeignType {}) = True
isTypeOrClassDecl other		   = False
342 343 344
\end{code}

Dealing with names
345

346
\begin{code}
347
--------------------------------
348
tyClDeclName :: TyClDecl name -> name
349
tyClDeclName tycl_decl = tcdName tycl_decl
350

351
--------------------------------
352
tyClDeclNames :: Eq name => TyClDecl name -> [(name, SrcLoc)]
353
-- Returns all the *binding* names of the decl, along with their SrcLocs
354 355 356 357
-- The first one is guaranteed to be the name of the decl
-- For record fields, the first one counts as the SrcLoc
-- We use the equality to filter out duplicate field names

358 359 360
tyClDeclNames (TySynonym   {tcdName = name, tcdLoc = loc})  = [(name,loc)]
tyClDeclNames (IfaceSig    {tcdName = name, tcdLoc = loc})  = [(name,loc)]
tyClDeclNames (ForeignType {tcdName = name, tcdLoc = loc})  = [(name,loc)]
361

362
tyClDeclNames (ClassDecl {tcdName = cls_name, tcdSigs = sigs, tcdLoc = loc})
363
  = (cls_name,loc) : [(n,loc) | ClassOpSig n _ _ loc <- sigs]
364

365
tyClDeclNames (TyData {tcdName = tc_name, tcdCons = cons, tcdLoc = loc})
366
  = (tc_name,loc) : conDeclsNames cons
367 368


369 370 371 372 373
tyClDeclTyVars (TySynonym {tcdTyVars = tvs}) = tvs
tyClDeclTyVars (TyData    {tcdTyVars = tvs}) = tvs
tyClDeclTyVars (ClassDecl {tcdTyVars = tvs}) = tvs
tyClDeclTyVars (ForeignType {})		     = []
tyClDeclTyVars (IfaceSig {})		     = []
374 375 376
\end{code}

\begin{code}
377
instance (NamedThing name, Ord name) => Eq (TyClDecl name) where
378
	-- Used only when building interface files
379 380 381 382 383
  (==) d1@(IfaceSig {}) d2@(IfaceSig {})
      = tcdName d1 == tcdName d2 && 
	tcdType d1 == tcdType d2 && 
	tcdIdInfo d1 == tcdIdInfo d2

384 385 386 387
  (==) d1@(ForeignType {}) d2@(ForeignType {})
      = tcdName d1 == tcdName d2 && 
	tcdFoType d1 == tcdFoType d2

388 389 390 391 392
  (==) d1@(TyData {}) d2@(TyData {})
      = tcdName d1 == tcdName d2 && 
	tcdND d1   == tcdND   d2 && 
	eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env -> 
   	  eq_hsContext env (tcdCtxt d1) (tcdCtxt d2)  &&
393
	  eq_hsCD      env (tcdCons d1) (tcdCons d2)
394 395 396 397 398 399 400 401 402 403 404 405 406 407
	)

  (==) d1@(TySynonym {}) d2@(TySynonym {})
      = tcdName d1 == tcdName d2 && 
	eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env -> 
          eq_hsType env (tcdSynRhs d1) (tcdSynRhs d2)
        )

  (==) d1@(ClassDecl {}) d2@(ClassDecl {})
    = tcdName d1 == tcdName d2 && 
      eqWithHsTyVars (tcdTyVars d1) (tcdTyVars d2) (\ env -> 
   	  eq_hsContext env (tcdCtxt d1) (tcdCtxt d2)  &&
	  eqListBy (eq_hsFD env) (tcdFDs d1) (tcdFDs d2) &&
	  eqListBy (eq_cls_sig env) (tcdSigs d1) (tcdSigs d2)
408 409
       )

410 411
  (==) _ _ = False	-- default case

412 413 414 415 416
eq_hsCD env (DataCons c1) (DataCons c2) = eqListBy (eq_ConDecl env) c1 c2
eq_hsCD env Unknown	  Unknown	= True
eq_hsCD env (HasCons n1)  (HasCons n2)  = n1 == n2
eq_hsCD env d1		  d2		= False

417 418 419
eq_hsFD env (ns1,ms1) (ns2,ms2)
  = eqListBy (eq_hsVar env) ns1 ns2 && eqListBy (eq_hsVar env) ms1 ms2

420 421 422
eq_cls_sig env (ClassOpSig n1 dm1 ty1 _) (ClassOpSig n2 dm2 ty2 _)
  = n1==n2 && dm1 `eq_dm` dm2 && eq_hsType env ty1 ty2
  where
423
	-- Ignore the name of the default method for (DefMeth id)
424 425 426
	-- This is used for comparing declarations before putting
	-- them into interface files, and the name of the default 
	-- method isn't relevant
427 428 429 430
    NoDefMeth  `eq_dm` NoDefMeth  = True
    GenDefMeth `eq_dm` GenDefMeth = True
    DefMeth _  `eq_dm` DefMeth _  = True
    dm1	       `eq_dm` dm2	  = False
431 432 433
\end{code}

\begin{code}
434
countTyClDecls :: [TyClDecl name] -> (Int, Int, Int, Int, Int)
435 436
	-- class, data, newtype, synonym decls
countTyClDecls decls 
sof's avatar
sof committed
437 438
 = (count isClassDecl     decls,
    count isSynDecl       decls,
439
    count isIfaceSigDecl  decls,
sof's avatar
sof committed
440 441 442 443 444 445 446 447
    count isDataTy        decls,
    count isNewTy         decls) 
 where
   isDataTy TyData{tcdND=DataType} = True
   isDataTy _                      = False
   
   isNewTy TyData{tcdND=NewType} = True
   isNewTy _                     = False
448 449 450
\end{code}

\begin{code}
451 452
instance OutputableBndr name
	      => Outputable (TyClDecl name) where
453

454
    ppr (IfaceSig {tcdName = var, tcdType = ty, tcdIdInfo = info})
455
	= getPprStyle $ \ sty ->
456
	   hsep [ pprHsVar var, dcolon, ppr ty, pprHsIdInfo info ]
457

458 459 460
    ppr (ForeignType {tcdName = tycon})
	= hsep [ptext SLIT("foreign import type dotnet"), ppr tycon]

461
    ppr (TySynonym {tcdName = tycon, tcdTyVars = tyvars, tcdSynRhs = mono_ty})
462
      = hang (ptext SLIT("type") <+> pp_decl_head [] tycon tyvars <+> equals)
463
	     4 (ppr mono_ty)
464

465
    ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdName = tycon,
466
		 tcdTyVars = tyvars, tcdCons = condecls, 
467
		 tcdDerivs = derivings})
468
      = pp_tydecl (ptext keyword <+> pp_decl_head context tycon tyvars)
469
		  (pp_condecls condecls)
470
		  derivings
sof's avatar
sof committed
471 472 473 474
      where
	keyword = case new_or_data of
			NewType  -> SLIT("newtype")
			DataType -> SLIT("data")
475

476 477
    ppr (ClassDecl {tcdCtxt = context, tcdName = clas, tcdTyVars = tyvars, tcdFDs = fds,
		    tcdSigs = sigs, tcdMeths = methods})
478 479 480 481 482
      | null sigs	-- No "where" part
      = top_matter

      | otherwise	-- Laid out
      = sep [hsep [top_matter, ptext SLIT("where {")],
483
	     nest 4 (sep [sep (map ppr_sig sigs), pp_methods, char '}'])]
484
      where
485
        top_matter  = ptext SLIT("class") <+> pp_decl_head context clas tyvars <+> pprFundeps fds
486
	ppr_sig sig = ppr sig <> semi
487

488
	pp_methods = if isNothing methods
489 490
			then empty
			else ppr (fromJust methods)
sof's avatar
sof committed
491

492
pp_decl_head :: OutputableBndr name => HsContext name -> name -> [HsTyVarBndr name] -> SDoc
493
pp_decl_head context thing tyvars = hsep [pprHsContext context, ppr thing, interppSP tyvars]
494

495 496 497
pp_condecls Unknown	  = ptext SLIT("{- abstract -}")
pp_condecls (HasCons n)   = ptext SLIT("{- abstract with") <+> int n <+> ptext SLIT("constructors -}")
pp_condecls (DataCons cs) = equals <+> sep (punctuate (ptext SLIT(" |")) (map ppr cs))
498

499
pp_tydecl pp_head pp_decl_rhs derivings
sof's avatar
sof committed
500
  = hang pp_head 4 (sep [
501
	pp_decl_rhs,
502 503
	case derivings of
	  Nothing 	   -> empty
504
	  Just ds	   -> hsep [ptext SLIT("deriving"), ppr_hs_context ds]
505
    ])
506 507 508 509 510 511 512 513 514 515 516
\end{code}


%************************************************************************
%*									*
\subsection[ConDecl]{A data-constructor declaration}
%*									*
%************************************************************************

\begin{code}
data ConDecl name
517 518 519
  = ConDecl 	name			-- Constructor name; this is used for the
					-- DataCon itself, and for the user-callable wrapper Id

520
		[HsTyVarBndr name]	-- Existentially quantified type variables
521
		(HsContext name)	-- ...and context
522 523
					-- If both are empty then there are no existentials

524
		(HsConDetails name (BangType name))
525
		SrcLoc
526 527 528
\end{code}

\begin{code}
529
conDeclsNames :: Eq name => DataConDetails (ConDecl name) -> [(name,SrcLoc)]
530 531 532 533
  -- See tyClDeclNames for what this does
  -- The function is boringly complicated because of the records
  -- And since we only have equality, we have to be a little careful
conDeclsNames cons
534
  = snd (foldl do_one ([], []) (visibleDataCons cons))
535
  where
536 537
    do_one (flds_seen, acc) (ConDecl name _ _ (RecCon flds) loc)
	= (new_flds ++ flds_seen, (name,loc) : [(f,loc) | f <- new_flds] ++ acc)
538
	where
539
	  new_flds = [ f | (f,_) <- flds, not (f `elem` flds_seen) ]
540

541 542
    do_one (flds_seen, acc) (ConDecl name _ _ _ loc)
	= (flds_seen, (name,loc):acc)
543 544 545
\end{code}

\begin{code}
546
conDetailsTys details = map getBangType (hsConArgs details)
547

548 549
eq_ConDecl env (ConDecl n1 tvs1 cxt1 cds1 _)
	       (ConDecl n2 tvs2 cxt2 cds2 _)
550
  = n1 == n2 &&
551
    (eq_hsTyVars env tvs1 tvs2	$ \ env ->
552 553 554
     eq_hsContext env cxt1 cxt2	&&
     eq_ConDetails env cds1 cds2)

555
eq_ConDetails env (PrefixCon bts1) (PrefixCon bts2)
556 557 558 559 560 561 562 563
  = eqListBy (eq_btype env) bts1 bts2
eq_ConDetails env (InfixCon bta1 btb1) (InfixCon bta2 btb2)
  = eq_btype env bta1 bta2 && eq_btype env btb1 btb2
eq_ConDetails env (RecCon fs1) (RecCon fs2)
  = eqListBy (eq_fld env) fs1 fs2
eq_ConDetails env _ _ = False

eq_fld env (ns1,bt1) (ns2, bt2) = ns1==ns2 && eq_btype env bt1 bt2
564
\end{code}
565
  
566
\begin{code}
567 568 569 570 571 572 573 574
data BangType name = BangType StrictnessMark (HsType name)

getBangType       (BangType _ ty) = ty
getBangStrictness (BangType s _)  = s

unbangedType ty = BangType NotMarkedStrict ty

eq_btype env (BangType s1 t1) (BangType s2 t2) = s1==s2 && eq_hsType env t1 t2
575 576 577
\end{code}

\begin{code}
578 579
instance (OutputableBndr name) => Outputable (ConDecl name) where
    ppr (ConDecl con tvs cxt con_details loc)
580
      = sep [pprHsForAll tvs cxt, ppr_con_details con con_details]
581

582 583
ppr_con_details con (InfixCon ty1 ty2)
  = hsep [ppr_bang ty1, ppr con, ppr_bang ty2]
584

585
-- ConDecls generated by MkIface.ifaceTyThing always have a PrefixCon, even
586 587 588
-- if the constructor is an infix one.  This is because in an interface file
-- we don't distinguish between the two.  Hence when printing these for the
-- user, we need to parenthesise infix constructor names.
589 590
ppr_con_details con (PrefixCon tys)
  = hsep (pprHsVar con : map ppr_bang tys)
sof's avatar
sof committed
591

592
ppr_con_details con (RecCon fields)
593
  = ppr con <+> braces (sep (punctuate comma (map ppr_field fields)))
sof's avatar
sof committed
594
  where
595
    ppr_field (n, ty) = ppr n <+> dcolon <+> ppr_bang ty
sof's avatar
sof committed
596

597
instance OutputableBndr name => Outputable (BangType name) where
598 599
    ppr = ppr_bang

600
ppr_bang (BangType s ty) = ppr s <> pprParendHsType ty
601 602 603 604 605
\end{code}


%************************************************************************
%*									*
sof's avatar
sof committed
606
\subsection[InstDecl]{An instance declaration
607 608 609 610
%*									*
%************************************************************************

\begin{code}
611
data InstDecl name
612
  = InstDecl	(HsType name)	-- Context => Class Instance-type
613 614 615
				-- Using a polytype means that the renamer conveniently
				-- figures out the quantified type variables for us.

616
		(MonoBinds name)
617

618
		[Sig name]		-- User-supplied pragmatic info
619

620 621
		(Maybe name)		-- Name for the dictionary function
					-- Nothing for source-file instance decls
622 623

		SrcLoc
624

625
isSourceInstDecl :: InstDecl name -> Bool
626
isSourceInstDecl (InstDecl _ _ _ maybe_dfun _) = isNothing maybe_dfun
627 628 629
\end{code}

\begin{code}
630
instance (OutputableBndr name) => Outputable (InstDecl name) where
631

632
    ppr (InstDecl inst_ty binds uprags maybe_dfun_name src_loc)
633 634 635
      = vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")],
	      nest 4 (ppr uprags),
	      nest 4 (ppr binds) ]
636 637 638 639
      where
	pp_dfun = case maybe_dfun_name of
		    Just df -> ppr df
		    Nothing -> empty
640 641
\end{code}

642
\begin{code}
643
instance Ord name => Eq (InstDecl name) where
644 645 646 647 648
	-- Used for interface comparison only, so don't compare bindings
  (==) (InstDecl inst_ty1 _ _ dfun1 _) (InstDecl inst_ty2 _ _ dfun2 _)
       = inst_ty1 == inst_ty2 && dfun1 == dfun2
\end{code}

649 650 651 652 653 654 655 656 657 658 659 660 661

%************************************************************************
%*									*
\subsection[DefaultDecl]{A @default@ declaration}
%*									*
%************************************************************************

There can only be one default declaration per module, but it is hard
for the parser to check that; we pass them all through in the abstract
syntax, and that restriction must be checked in the front end.

\begin{code}
data DefaultDecl name
662
  = DefaultDecl	[HsType name]
663 664
		SrcLoc

665
instance (OutputableBndr name)
666 667
	      => Outputable (DefaultDecl name) where

668 669
    ppr (DefaultDecl tys src_loc)
      = ptext SLIT("default") <+> parens (interpp'SP tys)
670
\end{code}
671

sof's avatar
sof committed
672 673 674 675 676 677 678
%************************************************************************
%*									*
\subsection{Foreign function interface declaration}
%*									*
%************************************************************************

\begin{code}
chak's avatar
chak committed
679 680 681 682 683 684 685

-- foreign declarations are distinguished as to whether they define or use a
-- Haskell name
--
-- * the Boolean value indicates whether the pre-standard deprecated syntax
--   has been used
--
686
data ForeignDecl name
chak's avatar
chak committed
687 688
  = ForeignImport name (HsType name) ForeignImport Bool SrcLoc  -- defines name
  | ForeignExport name (HsType name) ForeignExport Bool SrcLoc  -- uses name
689

chak's avatar
chak committed
690 691 692 693 694
-- yield the Haskell name defined or used in a foreign declaration
--
foreignDeclName                           :: ForeignDecl name -> name
foreignDeclName (ForeignImport n _ _ _ _)  = n
foreignDeclName (ForeignExport n _ _ _ _)  = n
695

chak's avatar
chak committed
696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728
-- specification of an imported external entity in dependence on the calling
-- convention 
--
data ForeignImport = -- import of a C entity
		     --
                     -- * the two strings specifying a header file or library
                     --   may be empty, which indicates the absence of a
                     --   header or object specification (both are not used
                     --   in the case of `CWrapper' and when `CFunction'
                     --   has a dynamic target)
		     --
		     -- * the calling convention is irrelevant for code
		     --   generation in the case of `CLabel', but is needed
		     --   for pretty printing 
		     --
		     -- * `Safety' is irrelevant for `CLabel' and `CWrapper'
		     --
		     CImport  CCallConv	      -- ccall or stdcall
			      Safety	      -- safe or unsafe
			      FastString      -- name of C header
			      FastString      -- name of library object
			      CImportSpec     -- details of the C entity

                     -- import of a .NET function
		     --
		   | DNImport DNCallSpec

-- details of an external C entity
--
data CImportSpec = CLabel    CLabelString     -- import address of a C label
		 | CFunction CCallTarget      -- static or dynamic function
		 | CWrapper		      -- wrapper to expose closures
					      -- (former f.e.d.)
729

chak's avatar
chak committed
730 731 732 733 734
-- specification of an externally exported entity in dependence on the calling
-- convention
--
data ForeignExport = CExport  CExportSpec    -- contains the calling convention
		   | DNExport		     -- presently unused
735

chak's avatar
chak committed
736 737
-- abstract type imported from .NET
--
738
data FoType = DNType 		-- In due course we'll add subtype stuff
chak's avatar
chak committed
739 740 741 742 743
	    deriving (Eq)	-- Used for equality instance for TyClDecl


-- pretty printing of foreign declarations
--
744

745
instance OutputableBndr name => Outputable (ForeignDecl name) where
chak's avatar
chak committed
746 747 748 749 750 751 752 753 754 755 756 757 758 759 760
  ppr (ForeignImport n ty fimport _ _) =
    ptext SLIT("foreign import") <+> ppr fimport <+> 
    ppr n <+> dcolon <+> ppr ty
  ppr (ForeignExport n ty fexport _ _) =
    ptext SLIT("foreign export") <+> ppr fexport <+> 
    ppr n <+> dcolon <+> ppr ty

instance Outputable ForeignImport where
  ppr (DNImport			        spec) = 
    ptext SLIT("dotnet") <+> ppr spec
  ppr (CImport  cconv safety header lib spec) =
    ppr cconv <+> ppr safety <+> 
    char '"' <> pprCEntity header lib spec <> char '"'
    where
      pprCEntity header lib (CLabel lbl) = 
761
        ptext SLIT("static") <+> ftext header <+> char '&' <>
chak's avatar
chak committed
762 763
	pprLib lib <> ppr lbl
      pprCEntity header lib (CFunction (StaticTarget lbl)) = 
764
        ptext SLIT("static") <+> ftext header <+> char '&' <>
chak's avatar
chak committed
765 766 767 768 769 770 771 772 773 774 775 776 777 778 779
	pprLib lib <> ppr lbl
      pprCEntity header lib (CFunction (DynamicTarget)) = 
        ptext SLIT("dynamic")
      pprCEntity header lib (CFunction (CasmTarget _)) = 
        panic "HsDecls.pprCEntity: malformed C function target"
      pprCEntity _      _   (CWrapper) = ptext SLIT("wrapper")
      --
      pprLib lib | nullFastString lib = empty
		 | otherwise	      = char '[' <> ppr lib <> char ']'

instance Outputable ForeignExport where
  ppr (CExport  (CExportStatic lbl cconv)) = 
    ppr cconv <+> char '"' <> ppr lbl <> char '"'
  ppr (DNExport                          ) = 
    ptext SLIT("dotnet") <+> ptext SLIT("\"<unused>\"")
780 781

instance Outputable FoType where
chak's avatar
chak committed
782
  ppr DNType = ptext SLIT("type dotnet")
sof's avatar
sof committed
783 784
\end{code}

785

786 787
%************************************************************************
%*									*
788
\subsection{Transformation rules}
789 790 791 792
%*									*
%************************************************************************

\begin{code}
793
data RuleDecl name
794
  = HsRule			-- Source rule
795 796
	RuleName		-- Rule name
	Activation
797
	[RuleBndr name]		-- Forall'd vars; after typechecking this includes tyvars
798 799
	(HsExpr name)	-- LHS
	(HsExpr name)	-- RHS
800 801
	SrcLoc		

802
  | IfaceRule	 		-- One that's come in from an interface file; pre-typecheck
803 804
	RuleName
	Activation
805 806 807 808
	[UfBinder name]		-- Tyvars and term vars
	name			-- Head of lhs
	[UfExpr name]		-- Args of LHS
	(UfExpr name)		-- Pre typecheck
809 810
	SrcLoc		

811 812 813 814
  | IfaceRuleOut		-- Post typecheck
	name			-- Head of LHS
	CoreRule

815 816 817 818
isSrcRule (HsRule _ _ _ _ _ _) = True
isSrcRule other		       = False

ifaceRuleDeclName :: RuleDecl name -> name
819 820
ifaceRuleDeclName (IfaceRule _ _ _ n _ _ _) = n
ifaceRuleDeclName (IfaceRuleOut n r)	    = n
821
ifaceRuleDeclName (HsRule fs _ _ _ _ _)     = pprPanic "ifaceRuleDeclName" (ppr fs)
822

823 824 825
data RuleBndr name
  = RuleBndr name
  | RuleBndrSig name (HsType name)
826

827 828 829
collectRuleBndrSigTys :: [RuleBndr name] -> [HsType name]
collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]

830
instance (NamedThing name, Ord name) => Eq (RuleDecl name) where
831
  -- Works for IfaceRules only; used when comparing interface file versions
832 833
  (IfaceRule n1 a1 bs1 f1 es1 rhs1 _) == (IfaceRule n2 a2 bs2 f2 es2 rhs2 _)
     = n1==n2 && f1 == f2 && a1==a2 &&
834 835 836
       eq_ufBinders emptyEqHsEnv bs1 bs2 (\env -> 
       eqListBy (eq_ufExpr env) (rhs1:es1) (rhs2:es2))

837
instance OutputableBndr name => Outputable (RuleDecl name) where
838
  ppr (HsRule name act ns lhs rhs loc)
839
	= sep [text "{-# RULES" <+> doubleQuotes (ftext name) <+> ppr act,
840
	       pp_forall, pprExpr lhs, equals <+> pprExpr rhs,
841
               text "#-}" ]
842
	where
843 844
	  pp_forall | null ns   = empty
		    | otherwise	= text "forall" <+> fsep (map ppr ns) <> dot
845

846
  ppr (IfaceRule name act tpl_vars fn tpl_args rhs loc) 
847
    = hsep [ doubleQuotes (ftext name), ppr act,
848 849 850 851 852 853
	   ptext SLIT("__forall") <+> braces (interppSP tpl_vars),
	   ppr fn <+> sep (map (pprUfExpr parens) tpl_args),
	   ptext SLIT("=") <+> ppr rhs
      ] <+> semi

  ppr (IfaceRuleOut fn rule) = pprCoreRule (ppr fn) rule
854

855
instance OutputableBndr name => Outputable (RuleBndr name) where
856 857
   ppr (RuleBndr name) = ppr name
   ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
858 859 860 861 862 863 864 865 866
\end{code}


%************************************************************************
%*									*
\subsection[DeprecDecl]{Deprecations}
%*									*
%************************************************************************

867
We use exported entities for things to deprecate.
868 869

\begin{code}
870
data DeprecDecl name = Deprecation name DeprecTxt SrcLoc
871

872
type DeprecTxt = FastString	-- reason/explanation for deprecation
873

874
instance OutputableBndr name => Outputable (DeprecDecl name) where
875
    ppr (Deprecation thing txt _)
876
      = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]
877
\end{code}
878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897


%************************************************************************
%*									*
		External-core declarations
%*									*
%************************************************************************

\begin{code}
data CoreDecl name	-- a Core value binding (from 'external Core' input)
  = CoreDecl 	name
		(HsType name)
		(UfExpr name)
		SrcLoc
        
instance OutputableBndr name => Outputable (CoreDecl name) where
    ppr (CoreDecl var ty rhs loc)
	= getPprStyle $ \ sty ->
	  hsep [ pprHsVar var, dcolon, ppr ty, ppr rhs ]
\end{code}