HsDecls.lhs 23.9 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 12 13 14 15
	HsDecl(..), LHsDecl, TyClDecl(..), LTyClDecl, 
	InstDecl(..), LInstDecl,
	RuleDecl(..), LRuleDecl, RuleBndr(..),
	DefaultDecl(..), LDefaultDecl, HsGroup(..), SpliceDecl(..),
	ForeignDecl(..), LForeignDecl, ForeignImport(..), ForeignExport(..),
chak's avatar
chak committed
16
	CImportSpec(..), FoType(..),
17 18 19 20 21
	ConDecl(..), LConDecl,
	LBangType, BangType(..), HsBang(..), 
	getBangType, getBangStrictness, unbangedType, 
	DeprecDecl(..),  LDeprecDecl,
	tcdName, tyClDeclNames, tyClDeclTyVars,
22 23
	isClassDecl, isSynDecl, isDataDecl, 
	countTyClDecls,
24
	conDetailsTys,
25
	collectRuleBndrSigTys, 
26
    ) where
27

28
#include "HsVersions.h"
29 30

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

34 35
import HsBinds		( HsBindGroup, HsBind, LHsBinds, 
			  Sig(..), LSig, LFixitySig )
36 37
import HsPat		( HsConDetails(..), hsConArgs )
import HsImpExp		( pprHsVar )
38
import HsTypes
39 40 41
import HscTypes		( DeprecTxt )
import CoreSyn		( RuleName )
import BasicTypes	( NewOrData(..), Activation(..) )
chak's avatar
chak committed
42 43
import ForeignCall	( CCallTarget(..), DNCallSpec, CCallConv, Safety,
			  CExportSpec(..)) 
44 45

-- others:
46
import FunDeps		( pprFundeps )
47
import Class		( FunDep )
48
import CStrings		( CLabelString )
49
import Outputable	
50
import Util		( count )
51
import SrcLoc		( Located(..), unLoc )
rrt's avatar
rrt committed
52
import FastString
53 54
\end{code}

55 56 57 58 59 60 61 62

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

\begin{code}
63 64
type LHsDecl id = Located (HsDecl id)

65 66 67
data HsDecl id
  = TyClD	(TyClDecl id)
  | InstD	(InstDecl  id)
68
  | ValD	(HsBind id)
69
  | SigD	(Sig id)
70 71 72 73
  | DefD	(DefaultDecl id)
  | ForD        (ForeignDecl id)
  | DeprecD	(DeprecDecl id)
  | RuleD	(RuleDecl id)
74
  | SpliceD	(SpliceDecl id)
75 76

-- NB: all top-level fixity decls are contained EITHER
77
-- EITHER SigDs
78 79 80 81 82 83 84 85 86 87
-- 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
88

89 90 91 92
-- A [HsDecl] is categorised into a HsGroup before being 
-- fed to the renamer.
data HsGroup id
  = HsGroup {
93 94
	hs_valds  :: [HsBindGroup id],
		-- Before the renamer, this is a single big HsBindGroup,
95
		-- with all the bindings, and all the signatures.
96 97
		-- The renamer does dependency analysis, splitting it up
		-- into several HsBindGroups.
98

99 100
	hs_tyclds :: [LTyClDecl id],
	hs_instds :: [LInstDecl id],
101

102
	hs_fixds  :: [LFixitySig id],
103 104 105
		-- Snaffled out of both top-level fixity signatures,
		-- and those in class declarations

106 107 108 109
	hs_defds  :: [LDefaultDecl id],
	hs_fords  :: [LForeignDecl id],
	hs_depds  :: [LDeprecDecl id],
	hs_ruleds :: [LRuleDecl id]
110
  }
111 112 113
\end{code}

\begin{code}
114
instance OutputableBndr name => Outputable (HsDecl name) where
115
    ppr (TyClD dcl)  = ppr dcl
116 117 118
    ppr (ValD binds) = ppr binds
    ppr (DefD def)   = ppr def
    ppr (InstD inst) = ppr inst
sof's avatar
sof committed
119
    ppr (ForD fd)    = ppr fd
120
    ppr (SigD sd)    = ppr sd
121
    ppr (RuleD rd)   = ppr rd
122
    ppr (DeprecD dd) = ppr dd
123
    ppr (SpliceD dd) = ppr dd
124 125 126 127 128 129 130 131 132

instance OutputableBndr name => Outputable (HsGroup name) where
    ppr (HsGroup { hs_valds  = val_decls,
		   hs_tyclds = tycl_decls,
		   hs_instds = inst_decls,
		   hs_fixds  = fix_decls,
		   hs_depds  = deprec_decls,
		   hs_fords  = foreign_decls,
		   hs_defds  = default_decls,
133
		   hs_ruleds = rule_decls })
134 135 136 137
	= vcat [ppr_ds fix_decls, ppr_ds default_decls, 
		ppr_ds deprec_decls, ppr_ds rule_decls,
		ppr val_decls,
		ppr_ds tycl_decls, ppr_ds inst_decls,
138
		ppr_ds foreign_decls]
139 140 141
	where
	  ppr_ds [] = empty
	  ppr_ds ds = text "" $$ vcat (map ppr ds)
142

143
data SpliceDecl id = SpliceDecl (Located (HsExpr id))	-- Top level splice
144 145

instance OutputableBndr name => Outputable (SpliceDecl name) where
146
   ppr (SpliceDecl e) = ptext SLIT("$") <> parens (pprExpr (unLoc e))
147 148
\end{code}

149

150 151 152 153 154 155
%************************************************************************
%*									*
\subsection[TyDecl]{@data@, @newtype@ or @type@ (synonym) type declaration}
%*									*
%************************************************************************

156 157 158
		--------------------------------
			THE NAMING STORY
		--------------------------------
159

160 161
Here is the story about the implicit names that go with type, class,
and instance decls.  It's a bit tricky, so pay attention!
162 163 164

"Implicit" (or "system") binders
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
165 166 167 168 169 170 171 172 173
  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

174 175
All have occurrence names that are derived uniquely from their parent
declaration.
176 177 178 179 180 181 182 183 184

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
185 186 187 188 189
   (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
190

191 192
These are the two places that we have to conjure up the magic derived
names.  (The actual magic is in OccName.mkWorkerOcc, etc.)
193

194 195 196 197 198 199 200 201 202 203 204 205 206 207 208
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:
209

210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270
 - 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

271
  - The CoreTidy phase externalises the name, and ensures the occurrence name is
272 273 274 275 276 277 278 279 280 281 282 283
    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.
284

285 286
  - RnHsSyn.instDeclFVs treats the dict fun name as free in the decl, so that we
    suck in the dfun binding
287 288


289
\begin{code}
290 291 292 293 294
-- 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

295 296
type LTyClDecl name = Located (TyClDecl name)

297
data TyClDecl name
298 299 300 301 302
  = ForeignType { 
		tcdLName    :: Located name,
		tcdExtName  :: Maybe FastString,
		tcdFoType   :: FoType
  }
303

304
  | TyData {	tcdND     :: NewOrData,
305 306 307 308 309 310 311
		tcdCtxt   :: LHsContext name,	 	-- Context
		tcdLName  :: Located name,	 	-- Type constructor
		tcdTyVars :: [LHsTyVarBndr name], 	-- Type variables
		tcdCons	  :: [LConDecl name],	 	-- Data constructors
		tcdDerivs :: Maybe (LHsContext name)	
			-- Derivings; Nothing => not specified
			-- 	      Just [] => derive exactly what is asked
312 313
    }

314 315 316
  | TySynonym {	tcdLName  :: Located name,	        -- type constructor
		tcdTyVars :: [LHsTyVarBndr name],	-- type variables
		tcdSynRhs :: LHsType name	        -- synonym expansion
317 318
    }

319 320 321 322 323 324
  | ClassDecl {	tcdCtxt    :: LHsContext name, 	 	-- Context...
		tcdLName   :: Located name,	    	-- Name of the class
		tcdTyVars  :: [LHsTyVarBndr name],	-- Class type variables
		tcdFDs     :: [Located (FunDep name)],	-- Functional deps
		tcdSigs    :: [LSig name],		-- Methods' signatures
		tcdMeths   :: LHsBinds name		-- Default methods
325
    }
326 327 328 329 330
\end{code}

Simple classifiers

\begin{code}
331
isDataDecl, isSynDecl, isClassDecl :: TyClDecl name -> Bool
332

333 334
isSynDecl (TySynonym {}) = True
isSynDecl other		 = False
335

336 337
isDataDecl (TyData {}) = True
isDataDecl other       = False
338

339 340
isClassDecl (ClassDecl {}) = True
isClassDecl other	   = False
341 342 343
\end{code}

Dealing with names
344

345
\begin{code}
346 347
tcdName :: TyClDecl name -> name
tcdName decl = unLoc (tcdLName decl)
348

349
tyClDeclNames :: Eq name => TyClDecl name -> [Located name]
350
-- Returns all the *binding* names of the decl, along with their SrcLocs
351 352 353 354
-- 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

355 356
tyClDeclNames (TySynonym   {tcdLName = name})  = [name]
tyClDeclNames (ForeignType {tcdLName = name})  = [name]
357

358 359
tyClDeclNames (ClassDecl {tcdLName = cls_name, tcdSigs = sigs})
  = cls_name : [n | L _ (Sig n _) <- sigs]
360

361 362
tyClDeclNames (TyData {tcdLName = tc_name, tcdCons = cons})
  = tc_name : conDeclsNames (map unLoc cons)
363

364 365 366 367
tyClDeclTyVars (TySynonym {tcdTyVars = tvs}) = tvs
tyClDeclTyVars (TyData    {tcdTyVars = tvs}) = tvs
tyClDeclTyVars (ClassDecl {tcdTyVars = tvs}) = tvs
tyClDeclTyVars (ForeignType {})		     = []
368 369 370
\end{code}

\begin{code}
371
countTyClDecls :: [TyClDecl name] -> (Int, Int, Int, Int)
372 373
	-- class, data, newtype, synonym decls
countTyClDecls decls 
sof's avatar
sof committed
374 375 376 377 378 379 380 381 382 383
 = (count isClassDecl     decls,
    count isSynDecl       decls,
    count isDataTy        decls,
    count isNewTy         decls) 
 where
   isDataTy TyData{tcdND=DataType} = True
   isDataTy _                      = False
   
   isNewTy TyData{tcdND=NewType} = True
   isNewTy _                     = False
384 385 386
\end{code}

\begin{code}
387 388
instance OutputableBndr name
	      => Outputable (TyClDecl name) where
389

390 391
    ppr (ForeignType {tcdLName = ltycon})
	= hsep [ptext SLIT("foreign import type dotnet"), ppr ltycon]
392

393 394
    ppr (TySynonym {tcdLName = ltycon, tcdTyVars = tyvars, tcdSynRhs = mono_ty})
      = hang (ptext SLIT("type") <+> pp_decl_head [] ltycon tyvars <+> equals)
395
	     4 (ppr mono_ty)
396

397
    ppr (TyData {tcdND = new_or_data, tcdCtxt = context, tcdLName = ltycon,
398
		 tcdTyVars = tyvars, tcdCons = condecls, 
399
		 tcdDerivs = derivings})
400
      = pp_tydecl (ppr new_or_data <+> pp_decl_head (unLoc context) ltycon tyvars)
401
		  (pp_condecls condecls)
402 403
		  derivings

404
    ppr (ClassDecl {tcdCtxt = context, tcdLName = lclas, tcdTyVars = tyvars, tcdFDs = fds,
405
		    tcdSigs = sigs, tcdMeths = methods})
406 407 408 409 410
      | null sigs	-- No "where" part
      = top_matter

      | otherwise	-- Laid out
      = sep [hsep [top_matter, ptext SLIT("where {")],
411
	     nest 4 (sep [sep (map ppr_sig sigs), ppr methods, char '}'])]
412
      where
413
        top_matter  = ptext SLIT("class") <+> pp_decl_head (unLoc context) lclas tyvars <+> pprFundeps (map unLoc fds)
414
	ppr_sig sig = ppr sig <> semi
415

416 417 418 419 420 421 422
pp_decl_head :: OutputableBndr name
   => HsContext name
   -> Located name
   -> [LHsTyVarBndr name]
   -> SDoc
pp_decl_head context thing tyvars
  = hsep [pprHsContext context, ppr thing, interppSP tyvars]
423

424
pp_condecls cs = equals <+> sep (punctuate (ptext SLIT(" |")) (map ppr cs))
425

426
pp_tydecl pp_head pp_decl_rhs derivings
sof's avatar
sof committed
427
  = hang pp_head 4 (sep [
428
	pp_decl_rhs,
429 430
	case derivings of
	  Nothing 	   -> empty
431 432
	  Just ds	   -> hsep [ptext SLIT("deriving"), 
					ppr_hs_context (unLoc ds)]
433
    ])
434 435 436 437 438 439 440 441 442 443
\end{code}


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

\begin{code}
444 445
type LConDecl name = Located (ConDecl name)

446
data ConDecl name
447
  = ConDecl 	(Located name)		-- Constructor name; this is used for the
448 449
					-- DataCon itself, and for the user-callable wrapper Id

450 451
		[LHsTyVarBndr name]	-- Existentially quantified type variables
		(LHsContext name)	-- ...and context
452 453
					-- If both are empty then there are no existentials

454
		(HsConDetails name (LBangType name))
455 456 457
\end{code}

\begin{code}
458
conDeclsNames :: Eq name => [ConDecl name] -> [Located name]
459 460 461 462
  -- 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
463
  = snd (foldl do_one ([], []) cons)
464
  where
465 466
    do_one (flds_seen, acc) (ConDecl lname _ _ (RecCon flds))
	= (map unLoc new_flds ++ flds_seen, lname : [f | f <- new_flds] ++ acc)
467
	where
468
	  new_flds = [ f | (f,_) <- flds, not (unLoc f `elem` flds_seen) ]
469

470 471
    do_one (flds_seen, acc) (ConDecl lname _ _ _)
	= (flds_seen, lname:acc)
472

473
conDetailsTys details = map getBangType (hsConArgs details)
474
\end{code}
475
  
476
\begin{code}
477 478 479
type LBangType name = Located (BangType name)

data BangType name = BangType HsBang (LHsType name)
480 481 482

data HsBang = HsNoBang
	    | HsStrict	-- ! 
483
	    | HsUnbox	-- {-# UNPACK #-} ! (GHC extension, meaning "unbox")
484 485 486 487

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

488 489
unbangedType :: LHsType id -> LBangType id
unbangedType ty@(L loc _) = L loc (BangType HsNoBang ty)
490 491 492
\end{code}

\begin{code}
493
instance (OutputableBndr name) => Outputable (ConDecl name) where
494
    ppr (ConDecl con tvs cxt con_details)
495
      = sep [pprHsForAll Explicit tvs cxt, ppr_con_details con con_details]
496

497
ppr_con_details con (InfixCon ty1 ty2)
498
  = hsep [ppr ty1, ppr con, ppr ty2]
499

500
-- ConDecls generated by MkIface.ifaceTyThing always have a PrefixCon, even
501 502 503
-- 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.
504
ppr_con_details con (PrefixCon tys)
505
  = hsep (pprHsVar con : map ppr tys)
sof's avatar
sof committed
506

507
ppr_con_details con (RecCon fields)
508
  = ppr con <+> braces (sep (punctuate comma (map ppr_field fields)))
sof's avatar
sof committed
509
  where
510
    ppr_field (n, ty) = ppr n <+> dcolon <+> ppr ty
sof's avatar
sof committed
511

512
instance OutputableBndr name => Outputable (BangType name) where
513
    ppr (BangType is_strict ty) 
514
	= bang <> pprParendHsType (unLoc ty)
515 516 517 518 519
	where
	  bang = case is_strict of
			HsNoBang -> empty
			HsStrict -> char '!'
			HsUnbox  -> ptext SLIT("!!")
520 521 522 523 524
\end{code}


%************************************************************************
%*									*
sof's avatar
sof committed
525
\subsection[InstDecl]{An instance declaration
526 527 528 529
%*									*
%************************************************************************

\begin{code}
530 531
type LInstDecl name = Located (InstDecl name)

532
data InstDecl name
533
  = InstDecl	(LHsType name)	-- Context => Class Instance-type
534 535
				-- Using a polytype means that the renamer conveniently
				-- figures out the quantified type variables for us.
536 537
		(LHsBinds name)
		[LSig name]		-- User-supplied pragmatic info
538

539
instance (OutputableBndr name) => Outputable (InstDecl name) where
540

541
    ppr (InstDecl inst_ty binds uprags)
542 543 544
      = vcat [hsep [ptext SLIT("instance"), ppr inst_ty, ptext SLIT("where")],
	      nest 4 (ppr uprags),
	      nest 4 (ppr binds) ]
545 546
\end{code}

547 548 549 550 551 552 553 554 555 556 557
%************************************************************************
%*									*
\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}
558 559
type LDefaultDecl name = Located (DefaultDecl name)

560
data DefaultDecl name
561
  = DefaultDecl	[LHsType name]
562

563
instance (OutputableBndr name)
564 565
	      => Outputable (DefaultDecl name) where

566
    ppr (DefaultDecl tys)
567
      = ptext SLIT("default") <+> parens (interpp'SP tys)
568
\end{code}
569

sof's avatar
sof committed
570 571 572 573 574 575 576
%************************************************************************
%*									*
\subsection{Foreign function interface declaration}
%*									*
%************************************************************************

\begin{code}
chak's avatar
chak committed
577 578 579 580 581 582 583

-- 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
--
584 585
type LForeignDecl name = Located (ForeignDecl name)

586
data ForeignDecl name
587 588
  = ForeignImport (Located name) (LHsType name) ForeignImport Bool  -- defines name
  | ForeignExport (Located name) (LHsType name) ForeignExport Bool  -- uses name
589

chak's avatar
chak committed
590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622
-- 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.)
623

chak's avatar
chak committed
624 625 626 627 628
-- specification of an externally exported entity in dependence on the calling
-- convention
--
data ForeignExport = CExport  CExportSpec    -- contains the calling convention
		   | DNExport		     -- presently unused
629

chak's avatar
chak committed
630 631
-- abstract type imported from .NET
--
632
data FoType = DNType 		-- In due course we'll add subtype stuff
chak's avatar
chak committed
633 634 635 636 637
	    deriving (Eq)	-- Used for equality instance for TyClDecl


-- pretty printing of foreign declarations
--
638

639
instance OutputableBndr name => Outputable (ForeignDecl name) where
640
  ppr (ForeignImport n ty fimport _) =
chak's avatar
chak committed
641 642
    ptext SLIT("foreign import") <+> ppr fimport <+> 
    ppr n <+> dcolon <+> ppr ty
643
  ppr (ForeignExport n ty fexport _) =
chak's avatar
chak committed
644 645 646 647 648 649 650 651 652 653 654
    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) = 
655
        ptext SLIT("static") <+> ftext header <+> char '&' <>
chak's avatar
chak committed
656 657
	pprLib lib <> ppr lbl
      pprCEntity header lib (CFunction (StaticTarget lbl)) = 
658
        ptext SLIT("static") <+> ftext header <+> char '&' <>
chak's avatar
chak committed
659 660 661 662 663 664 665 666 667 668 669 670 671
	pprLib lib <> ppr lbl
      pprCEntity header lib (CFunction (DynamicTarget)) = 
        ptext SLIT("dynamic")
      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>\"")
672 673

instance Outputable FoType where
chak's avatar
chak committed
674
  ppr DNType = ptext SLIT("type dotnet")
sof's avatar
sof committed
675 676
\end{code}

677

678 679
%************************************************************************
%*									*
680
\subsection{Transformation rules}
681 682 683 684
%*									*
%************************************************************************

\begin{code}
685 686
type LRuleDecl name = Located (RuleDecl name)

687
data RuleDecl name
688
  = HsRule			-- Source rule
689 690
	RuleName		-- Rule name
	Activation
691
	[RuleBndr name]		-- Forall'd vars; after typechecking this includes tyvars
692 693
	(Located (HsExpr name))	-- LHS
	(Located (HsExpr name))	-- RHS
694 695

data RuleBndr name
696 697
  = RuleBndr (Located name)
  | RuleBndrSig (Located name) (LHsType name)
698

699
collectRuleBndrSigTys :: [RuleBndr name] -> [LHsType name]
700 701
collectRuleBndrSigTys bndrs = [ty | RuleBndrSig _ ty <- bndrs]

702
instance OutputableBndr name => Outputable (RuleDecl name) where
703
  ppr (HsRule name act ns lhs rhs)
704
	= sep [text "{-# RULES" <+> doubleQuotes (ftext name) <+> ppr act,
705 706
	       nest 4 (pp_forall <+> pprExpr (unLoc lhs)), 
	       nest 4 (equals <+> pprExpr (unLoc rhs) <+> text "#-}") ]
707
	where
708 709
	  pp_forall | null ns   = empty
		    | otherwise	= text "forall" <+> fsep (map ppr ns) <> dot
710

711
instance OutputableBndr name => Outputable (RuleBndr name) where
712 713
   ppr (RuleBndr name) = ppr name
   ppr (RuleBndrSig name ty) = ppr name <> dcolon <> ppr ty
714 715 716 717 718 719 720 721 722
\end{code}


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

723
We use exported entities for things to deprecate.
724 725

\begin{code}
726 727 728
type LDeprecDecl name = Located (DeprecDecl name)

data DeprecDecl name = Deprecation name DeprecTxt
729

730
instance OutputableBndr name => Outputable (DeprecDecl name) where
731
    ppr (Deprecation thing txt)
732
      = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]
733
\end{code}