Parser.y.pp 74.9 KB
Newer Older
1 2 3 4 5 6 7 8 9 10
--								-*-haskell-*-
-- ---------------------------------------------------------------------------
-- (c) The University of Glasgow 1997-2003
---
-- The GHC grammar.
--
-- Author(s): Simon Marlow, Sven Panne 1997, 1998, 1999
-- ---------------------------------------------------------------------------

{
11
{-# LANGUAGE BangPatterns #-} -- required for versions of Happy before 1.18.6
12
{-# OPTIONS -Wwarn -w #-}
13 14 15 16 17 18
-- The above warning supression flag is a temporary kludge.
-- While working on this module you are encouraged to remove it and fix
-- any warnings in the module. See
--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
-- for details

19 20 21 22 23 24 25 26
{-# OPTIONS_GHC -O0 -fno-ignore-interface-pragmas #-}
{-
Careful optimisation of the parser: we don't want to throw everything
at it, because that takes too long and doesn't buy much, but we do want
to inline certain key external functions, so we instruct GHC not to
throw away inlinings as it would normally do in -O0 mode.
-}

27
module Parser ( parseModule, parseStmt, parseIdentifier, parseType,
28
		parseHeader ) where
29 30 31

import HsSyn
import RdrHsSyn
Ian Lynagh's avatar
Ian Lynagh committed
32
import HscTypes		( IsBootInterface, WarningTxt(..) )
33 34 35
import Lexer
import RdrName
import TysWiredIn	( unitTyCon, unitDataCon, tupleTyCon, tupleCon, nilDataCon,
36
			  unboxedSingletonTyCon, unboxedSingletonDataCon,
37 38
			  listTyCon_RDR, parrTyCon_RDR, consDataCon_RDR )
import Type		( funTyCon )
39
import ForeignCall	( Safety(..), CExportSpec(..), CLabelString,
40 41
			  CCallConv(..), CCallTarget(..), defaultCCallConv
			)
42
import OccName		( varName, dataName, tcClsName, tvName )
43 44
import DataCon		( DataCon, dataConName )
import SrcLoc		( Located(..), unLoc, getLoc, noLoc, combineSrcSpans,
45 46
			  SrcSpan, combineLocs, srcLocFile, 
			  mkSrcLoc, mkSrcSpan )
47
import Module
andy@galois.com's avatar
andy@galois.com committed
48
import StaticFlags	( opt_SccProfilingOn, opt_Hpc )
49 50
import Type		( Kind, liftedTypeKind, unliftedTypeKind )
import Coercion		( mkArrowKind )
51
import Class		( FunDep )
52
import BasicTypes
53
import DynFlags
54
import OrdList
55
import HaddockUtils
56 57 58 59

import FastString
import Maybes		( orElse )
import Outputable
60

61
import Control.Monad    ( unless )
Simon Marlow's avatar
Simon Marlow committed
62
import GHC.Exts
63 64
import Data.Char
import Control.Monad    ( mplus )
65 66 67
}

{-
68 69 70 71 72 73 74 75 76 77 78
-----------------------------------------------------------------------------
24 Februar 2006

Conflicts: 33 shift/reduce
           1 reduce/reduce

The reduce/reduce conflict is weird.  It's between tyconsym and consym, and I
would think the two should never occur in the same context.

  -=chak

79 80 81 82 83 84 85 86 87 88 89
-----------------------------------------------------------------------------
31 December 2006

Conflicts: 34 shift/reduce
           1 reduce/reduce

The reduce/reduce conflict is weird.  It's between tyconsym and consym, and I
would think the two should never occur in the same context.

  -=chak

90 91 92 93 94 95 96 97 98 99 100
-----------------------------------------------------------------------------
6 December 2006

Conflicts: 32 shift/reduce
           1 reduce/reduce

The reduce/reduce conflict is weird.  It's between tyconsym and consym, and I
would think the two should never occur in the same context.

  -=chak

101 102 103 104 105 106 107 108 109 110 111
-----------------------------------------------------------------------------
26 July 2006

Conflicts: 37 shift/reduce
           1 reduce/reduce

The reduce/reduce conflict is weird.  It's between tyconsym and consym, and I
would think the two should never occur in the same context.

  -=chak

112
-----------------------------------------------------------------------------
113
Conflicts: 38 shift/reduce (1.25)
114

115
10 for abiguity in 'if x then y else z + 1'		[State 178]
116 117 118
	(shift parses as 'if x then y else (z + 1)', as per longest-parse rule)
	10 because op might be: : - ! * . `x` VARSYM CONSYM QVARSYM QCONSYM

119
1 for ambiguity in 'if x then y else z :: T'		[State 178]
120 121
	(shift parses as 'if x then y else (z :: T)', as per longest-parse rule)

122
4 for ambiguity in 'if x then y else z -< e'		[State 178]
123
	(shift parses as 'if x then y else (z -< T)', as per longest-parse rule)
124 125 126 127 128 129 130 131 132 133
	There are four such operators: -<, >-, -<<, >>-


2 for ambiguity in 'case v of { x :: T -> T ... } ' 	[States 11, 253]
 	Which of these two is intended?
	  case v of
	    (x::T) -> T		-- Rhs is T
    or
	  case v of
	    (x::T -> T) -> ..	-- Rhs is ...
134

135
10 for ambiguity in 'e :: a `b` c'.  Does this mean 	[States 11, 253]
136 137
	(e::a) `b` c, or 
	(e :: (a `b` c))
138
    As well as `b` we can have !, VARSYM, QCONSYM, and CONSYM, hence 5 cases
139
    Same duplication between states 11 and 253 as the previous case
140

141
1 for ambiguity in 'let ?x ...'				[State 329]
142 143 144 145
	the parser can't tell whether the ?x is the lhs of a normal binding or
	an implicit binding.  Fortunately resolving as shift gives it the only
	sensible meaning, namely the lhs of an implicit binding.

146
1 for ambiguity in '{-# RULES "name" [ ... #-}		[State 382]
147 148 149 150
	we don't know whether the '[' starts the activation or not: it
  	might be the start of the declaration with the activation being
	empty.  --SDM 1/4/2002

151
1 for ambiguity in '{-# RULES "name" forall = ... #-}' 	[State 474]
152 153 154 155 156 157 158
	since 'forall' is a valid variable name, we don't know whether
	to treat a forall on the input as the beginning of a quantifier
	or the beginning of the rule itself.  Resolving to shift means
	it's always treated as a quantifier, hence the above is disallowed.
	This saves explicitly defining a grammar for the rule lhs that
	doesn't include 'forall'.

159 160 161 162
1 for ambiguity when the source file starts with "-- | doc". We need another
  token of lookahead to determine if a top declaration or the 'module' keyword
  follows. Shift parses as if the 'module' keyword follows.   

163 164 165 166 167 168 169 170 171 172 173
-- ---------------------------------------------------------------------------
-- Adding location info

This is done in a stylised way using the three macros below, L0, L1
and LL.  Each of these macros can be thought of as having type

   L0, L1, LL :: a -> Located a

They each add a SrcSpan to their argument.

   L0	adds 'noSrcSpan', used for empty productions
174
     -- This doesn't seem to work anymore -=chak
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

   L1   for a production with a single token on the lhs.  Grabs the SrcSpan
	from that token.

   LL   for a production with >1 token on the lhs.  Makes up a SrcSpan from
        the first and last tokens.

These suffice for the majority of cases.  However, we must be
especially careful with empty productions: LL won't work if the first
or last token on the lhs can represent an empty span.  In these cases,
we have to calculate the span using more of the tokens from the lhs, eg.

	| 'newtype' tycl_hdr '=' newconstr deriving
		{ L (comb3 $1 $4 $5)
		    (mkTyData NewType (unLoc $2) [$4] (unLoc $5)) }

We provide comb3 and comb4 functions which are useful in such cases.

Be careful: there's no checking that you actually got this right, the
only symptom will be that the SrcSpans of your syntax will be
incorrect.

/*
 * We must expand these macros *before* running Happy, which is why this file is
 * Parser.y.pp rather than just Parser.y - we run the C pre-processor first.
 */
#define L0   L noSrcSpan
#define L1   sL (getLoc $1)
#define LL   sL (comb2 $1 $>)

-- -----------------------------------------------------------------------------

-}

%token
 '_'            { L _ ITunderscore }		-- Haskell keywords
 'as' 		{ L _ ITas }
 'case' 	{ L _ ITcase }  	
 'class' 	{ L _ ITclass } 
 'data' 	{ L _ ITdata } 
 'default' 	{ L _ ITdefault }
 'deriving' 	{ L _ ITderiving }
 'do' 		{ L _ ITdo }
 'else' 	{ L _ ITelse }
219
 'generic' 	{ L _ ITgeneric }
220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237
 'hiding' 	{ L _ IThiding }
 'if' 		{ L _ ITif }
 'import' 	{ L _ ITimport }
 'in' 		{ L _ ITin }
 'infix' 	{ L _ ITinfix }
 'infixl' 	{ L _ ITinfixl }
 'infixr' 	{ L _ ITinfixr }
 'instance' 	{ L _ ITinstance }
 'let' 		{ L _ ITlet }
 'module' 	{ L _ ITmodule }
 'newtype' 	{ L _ ITnewtype }
 'of' 		{ L _ ITof }
 'qualified' 	{ L _ ITqualified }
 'then' 	{ L _ ITthen }
 'type' 	{ L _ ITtype }
 'where' 	{ L _ ITwhere }
 '_scc_'	{ L _ ITscc }	      -- ToDo: remove

238
 'forall'	{ L _ ITforall }		-- GHC extension keywords
239 240 241 242 243
 'foreign'	{ L _ ITforeign }
 'export'	{ L _ ITexport }
 'label'	{ L _ ITlabel } 
 'dynamic'	{ L _ ITdynamic }
 'safe'		{ L _ ITsafe }
244
 'threadsafe'	{ L _ ITthreadsafe }  -- ToDo: remove deprecated alias
245
 'interruptible' { L _ ITinterruptible }
246 247
 'unsafe'	{ L _ ITunsafe }
 'mdo'		{ L _ ITmdo }
248
 'family'	{ L _ ITfamily }
249 250
 'stdcall'      { L _ ITstdcallconv }
 'ccall'        { L _ ITccallconv }
251
 'prim'         { L _ ITprimcallconv }
252 253
 'proc'		{ L _ ITproc }		-- for arrow notation extension
 'rec'		{ L _ ITrec }		-- for arrow notation extension
254 255 256
 'group'    { L _ ITgroup }     -- for list transform extension
 'by'       { L _ ITby }        -- for list transform extension
 'using'    { L _ ITusing }     -- for list transform extension
257

258
 '{-# INLINE'      	  { L _ (ITinline_prag _ _) }
259 260
 '{-# SPECIALISE'  	  { L _ ITspec_prag }
 '{-# SPECIALISE_INLINE'  { L _ (ITspec_inline_prag _) }
261 262 263 264
 '{-# SOURCE'	   { L _ ITsource_prag }
 '{-# RULES'	   { L _ ITrules_prag }
 '{-# CORE'        { L _ ITcore_prag }              -- hdaume: annotated core
 '{-# SCC'	   { L _ ITscc_prag }
andy@galois.com's avatar
andy@galois.com committed
265
 '{-# GENERATED'   { L _ ITgenerated_prag }
266
 '{-# DEPRECATED'  { L _ ITdeprecated_prag }
267
 '{-# WARNING'     { L _ ITwarning_prag }
268
 '{-# UNPACK'      { L _ ITunpack_prag }
269
 '{-# ANN'         { L _ ITann_prag }
270 271
 '{-# VECTORISE'          { L _ ITvect_prag }
 '{-# VECTORISE_SCALAR'   { L _ ITvect_scalar_prag }
272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321
 '#-}'		   { L _ ITclose_prag }

 '..'		{ L _ ITdotdot }  			-- reserved symbols
 ':'		{ L _ ITcolon }
 '::'		{ L _ ITdcolon }
 '='		{ L _ ITequal }
 '\\'		{ L _ ITlam }
 '|'		{ L _ ITvbar }
 '<-'		{ L _ ITlarrow }
 '->'		{ L _ ITrarrow }
 '@'		{ L _ ITat }
 '~'		{ L _ ITtilde }
 '=>'		{ L _ ITdarrow }
 '-'		{ L _ ITminus }
 '!'		{ L _ ITbang }
 '*'		{ L _ ITstar }
 '-<'		{ L _ ITlarrowtail }		-- for arrow notation
 '>-'		{ L _ ITrarrowtail }		-- for arrow notation
 '-<<'		{ L _ ITLarrowtail }		-- for arrow notation
 '>>-'		{ L _ ITRarrowtail }		-- for arrow notation
 '.'		{ L _ ITdot }

 '{'		{ L _ ITocurly } 			-- special symbols
 '}'		{ L _ ITccurly }
 '{|'           { L _ ITocurlybar }
 '|}'           { L _ ITccurlybar }
 vocurly	{ L _ ITvocurly } -- virtual open curly (from layout)
 vccurly	{ L _ ITvccurly } -- virtual close curly (from layout)
 '['		{ L _ ITobrack }
 ']'		{ L _ ITcbrack }
 '[:'		{ L _ ITopabrack }
 ':]'		{ L _ ITcpabrack }
 '('		{ L _ IToparen }
 ')'		{ L _ ITcparen }
 '(#'		{ L _ IToubxparen }
 '#)'		{ L _ ITcubxparen }
 '(|'		{ L _ IToparenbar }
 '|)'		{ L _ ITcparenbar }
 ';'		{ L _ ITsemi }
 ','		{ L _ ITcomma }
 '`'		{ L _ ITbackquote }

 VARID   	{ L _ (ITvarid    _) }		-- identifiers
 CONID   	{ L _ (ITconid    _) }
 VARSYM  	{ L _ (ITvarsym   _) }
 CONSYM  	{ L _ (ITconsym   _) }
 QVARID  	{ L _ (ITqvarid   _) }
 QCONID  	{ L _ (ITqconid   _) }
 QVARSYM 	{ L _ (ITqvarsym  _) }
 QCONSYM 	{ L _ (ITqconsym  _) }
322 323
 PREFIXQVARSYM  { L _ (ITprefixqvarsym  _) }
 PREFIXQCONSYM  { L _ (ITprefixqconsym  _) }
324 325 326 327 328 329 330 331 332 333 334

 IPDUPVARID   	{ L _ (ITdupipvarid   _) }		-- GHC extension

 CHAR		{ L _ (ITchar     _) }
 STRING		{ L _ (ITstring   _) }
 INTEGER	{ L _ (ITinteger  _) }
 RATIONAL	{ L _ (ITrational _) }
		    
 PRIMCHAR	{ L _ (ITprimchar   _) }
 PRIMSTRING	{ L _ (ITprimstring _) }
 PRIMINTEGER	{ L _ (ITprimint    _) }
Ian Lynagh's avatar
Ian Lynagh committed
335
 PRIMWORD 	{ L _ (ITprimword  _) }
336 337
 PRIMFLOAT	{ L _ (ITprimfloat  _) }
 PRIMDOUBLE	{ L _ (ITprimdouble _) }
338 339 340 341 342 343

 DOCNEXT	{ L _ (ITdocCommentNext _) }
 DOCPREV	{ L _ (ITdocCommentPrev _) }
 DOCNAMED	{ L _ (ITdocCommentNamed _) }
 DOCSECTION	{ L _ (ITdocSection _ _) }

344 345 346 347 348 349 350 351 352 353
-- Template Haskell 
'[|'            { L _ ITopenExpQuote  }       
'[p|'           { L _ ITopenPatQuote  }      
'[t|'           { L _ ITopenTypQuote  }      
'[d|'           { L _ ITopenDecQuote  }      
'|]'            { L _ ITcloseQuote    }
TH_ID_SPLICE    { L _ (ITidEscape _)  }     -- $x
'$('	        { L _ ITparenEscape   }     -- $( exp )
TH_VAR_QUOTE	{ L _ ITvarQuote      }     -- 'x
TH_TY_QUOTE	{ L _ ITtyQuote       }      -- ''T
354
TH_QUASIQUOTE	{ L _ (ITquasiQuote _) }
355 356 357 358 359 360

%monad { P } { >>= } { return }
%lexer { lexer } { L _ ITeof }
%name parseModule module
%name parseStmt   maybe_stmt
%name parseIdentifier  identifier
361
%name parseType ctype
362
%partial parseHeader header
363
%tokentype { (Located Token) }
364 365
%%

366 367 368 369 370 371 372
-----------------------------------------------------------------------------
-- Identifiers; one of the entry points
identifier :: { Located RdrName }
	: qvar				{ $1 }
	| qcon				{ $1 }
	| qvarop			{ $1 }
	| qconop			{ $1 }
373
    | '(' '->' ')'      { LL $ getRdrName funTyCon }
374

375 376 377 378 379 380 381 382 383 384 385
-----------------------------------------------------------------------------
-- Module Header

-- The place for module deprecation is really too restrictive, but if it
-- was allowed at its natural place just before 'module', we get an ugly
-- s/r conflict with the second alternative. Another solution would be the
-- introduction of a new pragma DEPRECATED_MODULE, but this is not very nice,
-- either, and DEPRECATED is only expected to be used by people who really
-- know what they are doing. :-)

module 	:: { Located (HsModule RdrName) }
Ian Lynagh's avatar
Ian Lynagh committed
386
 	: maybedocheader 'module' modid maybemodwarning maybeexports 'where' body
387 388 389
		{% fileSrcSpan >>= \ loc ->
		   return (L loc (HsModule (Just $3) $5 (fst $7) (snd $7) $4 $1
                          ) )}
390
        | body2
391
		{% fileSrcSpan >>= \ loc ->
David Waern's avatar
David Waern committed
392
		   return (L loc (HsModule Nothing Nothing
393 394
                          (fst $1) (snd $1) Nothing Nothing
                          )) }
395

396
maybedocheader :: { Maybe LHsDocString }
397
        : moduleheader            { $1 }
398
        | {- empty -}             { Nothing }
399 400 401 402

missing_module_keyword :: { () }
	: {- empty -}				{% pushCurrentContext }

Ian Lynagh's avatar
Ian Lynagh committed
403
maybemodwarning :: { Maybe WarningTxt }
404 405
    : '{-# DEPRECATED' strings '#-}' { Just (DeprecatedTxt $ unLoc $2) }
    | '{-# WARNING' strings '#-}'    { Just (WarningTxt $ unLoc $2) }
Ian Lynagh's avatar
Ian Lynagh committed
406
    |  {- empty -}                  { Nothing }
407 408 409 410 411

body 	:: { ([LImportDecl RdrName], [LHsDecl RdrName]) }
	:  '{'            top '}'		{ $2 }
 	|      vocurly    top close		{ $2 }

412 413 414 415
body2 	:: { ([LImportDecl RdrName], [LHsDecl RdrName]) }
	:  '{' top '}'          		{ $2 }
 	|  missing_module_keyword top close     { $2 }

416 417 418 419 420 421 422 423
top 	:: { ([LImportDecl RdrName], [LHsDecl RdrName]) }
	: importdecls				{ (reverse $1,[]) }
	| importdecls ';' cvtopdecls		{ (reverse $1,$3) }
	| cvtopdecls				{ ([],$1) }

cvtopdecls :: { [LHsDecl RdrName] }
	: topdecls				{ cvTopDecls $1 }

424 425 426 427
-----------------------------------------------------------------------------
-- Module declaration & imports only

header 	:: { Located (HsModule RdrName) }
Ian Lynagh's avatar
Ian Lynagh committed
428
 	: maybedocheader 'module' modid maybemodwarning maybeexports 'where' header_body
429 430 431
		{% fileSrcSpan >>= \ loc ->
		   return (L loc (HsModule (Just $3) $5 $7 [] $4 $1
                          ))}
432 433
	| missing_module_keyword importdecls
		{% fileSrcSpan >>= \ loc ->
David Waern's avatar
David Waern committed
434
		   return (L loc (HsModule Nothing Nothing $2 [] Nothing
435
                          Nothing)) }
436 437 438 439 440

header_body :: { [LImportDecl RdrName] }
	:  '{'            importdecls		{ $2 }
 	|      vocurly    importdecls		{ $2 }

441 442 443 444 445 446 447
-----------------------------------------------------------------------------
-- The Export List

maybeexports :: { Maybe [LIE RdrName] }
	:  '(' exportlist ')'			{ Just $2 }
	|  {- empty -}				{ Nothing }

448 449
exportlist :: { [LIE RdrName] }
	: expdoclist ',' expdoclist		{ $1 ++ $3 }
450 451 452
	| exportlist1				{ $1 }

exportlist1 :: { [LIE RdrName] }
453 454 455 456 457 458 459 460 461 462 463 464 465
        : expdoclist export expdoclist ',' exportlist  { $1 ++ ($2 : $3) ++ $5 }
 	| expdoclist export expdoclist	               { $1 ++ ($2 : $3) }
	| expdoclist				       { $1 }

expdoclist :: { [LIE RdrName] }
        : exp_doc expdoclist                           { $1 : $2 }
        | {- empty -}                                  { [] }

exp_doc :: { LIE RdrName }                                                   
        : docsection    { L1 (case (unLoc $1) of (n, doc) -> IEGroup n doc) }
        | docnamed      { L1 (IEDocNamed ((fst . unLoc) $1)) } 
        | docnext       { L1 (IEDoc (unLoc $1)) }       
                       
466 467 468 469 470 471 472 473 474 475 476
   -- No longer allow things like [] and (,,,) to be exported
   -- They are built in syntax, always available
export 	:: { LIE RdrName }
	:  qvar				{ L1 (IEVar (unLoc $1)) }
	|  oqtycon			{ L1 (IEThingAbs (unLoc $1)) }
	|  oqtycon '(' '..' ')'		{ LL (IEThingAll (unLoc $1)) }
	|  oqtycon '(' ')'		{ LL (IEThingWith (unLoc $1) []) }
	|  oqtycon '(' qcnames ')'	{ LL (IEThingWith (unLoc $1) (reverse $3)) }
	|  'module' modid		{ LL (IEModuleContents (unLoc $2)) }

qcnames :: { [RdrName] }
477 478
	:  qcnames ',' qcname_ext	{ unLoc $3 : $1 }
	|  qcname_ext			{ [unLoc $1]  }
479

480 481 482 483 484 485 486 487
qcname_ext :: { Located RdrName }	-- Variable or data constructor
					-- or tagged type constructor
	:  qcname			{ $1 }
	|  'type' qcon			{ sL (comb2 $1 $2) 
					     (setRdrNameSpace (unLoc $2) 
							      tcClsName)  }

-- Cannot pull into qcname_ext, as qcname is also used in expression.
488
qcname 	:: { Located RdrName }	-- Variable or data constructor
489 490
	:  qvar				{ $1 }
	|  qcon				{ $1 }
491 492 493 494 495 496 497 498 499 500 501 502 503 504

-----------------------------------------------------------------------------
-- Import Declarations

-- import decls can be *empty*, or even just a string of semicolons
-- whereas topdecls must contain at least one topdecl.

importdecls :: { [LImportDecl RdrName] }
	: importdecls ';' importdecl		{ $3 : $1 }
	| importdecls ';'			{ $1 }
	| importdecl				{ [ $1 ] }
	| {- empty -}				{ [] }

importdecl :: { LImportDecl RdrName }
505 506
	: 'import' maybe_src optqualified maybe_pkg modid maybeas maybeimpspec 
		{ L (comb4 $1 $5 $6 $7) (ImportDecl $5 $4 $2 $3 (unLoc $6) (unLoc $7)) }
507 508 509 510 511

maybe_src :: { IsBootInterface }
	: '{-# SOURCE' '#-}'			{ True }
	| {- empty -}				{ False }

512 513 514 515
maybe_pkg :: { Maybe FastString }
        : STRING                                { Just (getSTRING $1) }
        | {- empty -}                           { Nothing }

516 517 518 519
optqualified :: { Bool }
      	: 'qualified'                           { True  }
      	| {- empty -}				{ False }

Simon Marlow's avatar
Simon Marlow committed
520
maybeas :: { Located (Maybe ModuleName) }
521 522 523 524 525 526 527 528
      	: 'as' modid                            { LL (Just (unLoc $2)) }
      	| {- empty -}				{ noLoc Nothing }

maybeimpspec :: { Located (Maybe (Bool, [LIE RdrName])) }
	: impspec				{ L1 (Just (unLoc $1)) }
	| {- empty -}				{ noLoc Nothing }

impspec :: { Located (Bool, [LIE RdrName]) }
529 530
	:  '(' exportlist ')'  			{ LL (False, $2) }
	|  'hiding' '(' exportlist ')' 		{ LL (True,  $3) }
531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550

-----------------------------------------------------------------------------
-- Fixity Declarations

prec 	:: { Int }
	: {- empty -}		{ 9 }
	| INTEGER		{% checkPrecP (L1 (fromInteger (getINTEGER $1))) }

infix 	:: { Located FixityDirection }
	: 'infix'				{ L1 InfixN  }
	| 'infixl'				{ L1 InfixL  }
	| 'infixr'				{ L1 InfixR }

ops   	:: { Located [Located RdrName] }
	: ops ',' op				{ LL ($3 : unLoc $1) }
	| op					{ L1 [$1] }

-----------------------------------------------------------------------------
-- Top-Level Declarations

551
topdecls :: { OrdList (LHsDecl RdrName) }
552 553 554
        : topdecls ';' topdecl		        { $1 `appOL` $3 }
        | topdecls ';'			        { $1 }
	| topdecl			        { $1 }
555

556
topdecl :: { OrdList (LHsDecl RdrName) }
557
  	: cl_decl			{ unitOL (L1 (TyClD (unLoc $1))) }
chak@cse.unsw.edu.au.'s avatar
chak@cse.unsw.edu.au. committed
558
  	| ty_decl			{ unitOL (L1 (TyClD (unLoc $1))) }
559 560 561 562
	| 'instance' inst_type where_inst
	    { let (binds, sigs, ats, _) = cvBindsAndSigs (unLoc $3)
	      in 
	      unitOL (L (comb3 $1 $2 $3) (InstD (InstDecl $2 binds sigs ats)))}
563
        | stand_alone_deriving                  { unitOL (LL (DerivD (unLoc $1))) }
564 565
	| 'default' '(' comma_types0 ')'	{ unitOL (LL $ DefD (DefaultDecl $3)) }
	| 'foreign' fdecl			{ unitOL (LL (unLoc $2)) }
566 567
        | '{-# DEPRECATED' deprecations '#-}'   { $2 }
        | '{-# WARNING' warnings '#-}'          { $2 }
568
	| '{-# RULES' rules '#-}'		{ $2 }
569 570
	| '{-# VECTORISE_SCALAR' qvar '#-}'	{ unitOL $ LL $ VectD (HsVect $2 Nothing) }
	| '{-# VECTORISE' qvar '=' exp '#-}'	{ unitOL $ LL $ VectD (HsVect $2 (Just $4)) }
571
	| annotation { unitOL $1 }
572 573
      	| decl					{ unLoc $1 }

574
	-- Template Haskell Extension
575 576 577 578
	-- The $(..) form is one possible form of infixexp
	-- but we treat an arbitrary expression just as if 
	-- it had a $(..) wrapped around it
	| infixexp 				{ unitOL (LL $ mkTopSpliceDecl $1) } 
579

580 581 582
-- Type classes
--
cl_decl :: { LTyClDecl RdrName }
583
	: 'class' tycl_hdr fds where_cls	{% mkClassDecl (comb4 $1 $2 $3 $4) $2 $3 $4 }
584

585
-- Type declarations (toplevel)
586 587
--
ty_decl :: { LTyClDecl RdrName }
588
           -- ordinary type synonyms
589
        : 'type' type '=' ctypedoc
590 591 592 593
		-- Note ctype, not sigtype, on the right of '='
		-- We allow an explicit for-all but we don't insert one
		-- in 	type Foo a = (b,b)
		-- Instead we just say b is out of scope
594 595
	        --
		-- Note the use of type for the head; this allows
596
		-- infix type constructors to be declared 
597
 		{% mkTySynonym (comb2 $1 $4) False $2 $4 }
598 599

           -- type family declarations
600
        | 'type' 'family' type opt_kind_sig 
601 602
		-- Note the use of type for the head; this allows
		-- infix type constructors to be declared
603
 		{% mkTyFamily (comb3 $1 $3 $4) TypeFamily $3 (unLoc $4) }
604 605 606 607 608

           -- type instance declarations
        | 'type' 'instance' type '=' ctype
		-- Note the use of type for the head; this allows
		-- infix type constructors and type patterns
609
 		{% mkTySynonym (comb2 $1 $5) True $3 $5 }
610

611
          -- ordinary data type or newtype declaration
612
	| data_or_newtype tycl_hdr constrs deriving
613 614
		{% mkTyData (comb4 $1 $2 $3 $4) (unLoc $1) False $2 
                            Nothing (reverse (unLoc $3)) (unLoc $4) }
615 616
			           -- We need the location on tycl_hdr in case 
				   -- constrs and deriving are both empty
617

618
          -- ordinary GADT declaration
619
        | data_or_newtype tycl_hdr opt_kind_sig 
620
		 gadt_constrlist
621
		 deriving
622
		{% mkTyData (comb4 $1 $2 $4 $5) (unLoc $1) False $2 
623
                            (unLoc $3) (unLoc $4) (unLoc $5) }
624 625
			           -- We need the location on tycl_hdr in case 
				   -- constrs and deriving are both empty
626

627
          -- data/newtype family
628 629
        | 'data' 'family' type opt_kind_sig
		{% mkTyFamily (comb3 $1 $2 $4) DataFamily $3 (unLoc $4) }
630

631
          -- data/newtype instance declaration
632
	| data_or_newtype 'instance' tycl_hdr constrs deriving
633 634
		{% mkTyData (comb4 $1 $3 $4 $5) (unLoc $1) True $3
			    Nothing (reverse (unLoc $4)) (unLoc $5) }
635

636
          -- GADT instance declaration
637
        | data_or_newtype 'instance' tycl_hdr opt_kind_sig 
638
	         gadt_constrlist
639
		 deriving
640 641
		{% mkTyData (comb4 $1 $3 $5 $6) (unLoc $1) True $3
			    (unLoc $4) (unLoc $5) (unLoc $6) }
642 643

-- Associated type family declarations
644 645 646 647 648 649 650
--
-- * They have a different syntax than on the toplevel (no family special
--   identifier).
--
-- * They also need to be separate from instances; otherwise, data family
--   declarations without a kind signature cause parsing conflicts with empty
--   data declarations. 
651
--
652
at_decl_cls :: { LTyClDecl RdrName }
653
           -- type family declarations
654
        : 'type' type opt_kind_sig
655 656
		-- Note the use of type for the head; this allows
		-- infix type constructors to be declared
657
 		{% mkTyFamily (comb3 $1 $2 $3) TypeFamily $2 (unLoc $3) }
658

659
           -- default type instance
660
        | 'type' type '=' ctype
661 662
		-- Note the use of type for the head; this allows
		-- infix type constructors and type patterns
663
 		{% mkTySynonym (comb2 $1 $4) True $2 $4 }
664

665
          -- data/newtype family declaration
666 667 668 669
        | 'data' type opt_kind_sig
		{% mkTyFamily (comb3 $1 $2 $3) DataFamily $2 (unLoc $3) }

-- Associated type instances
670 671 672 673 674 675
--
at_decl_inst :: { LTyClDecl RdrName }
           -- type instance declarations
        : 'type' type '=' ctype
		-- Note the use of type for the head; this allows
		-- infix type constructors and type patterns
676
 		{% mkTySynonym (comb2 $1 $4) True $2 $4 }
677 678 679

        -- data/newtype instance declaration
	| data_or_newtype tycl_hdr constrs deriving
680 681
		{% mkTyData (comb4 $1 $2 $3 $4) (unLoc $1) True $2 
                            Nothing (reverse (unLoc $3)) (unLoc $4) }
682 683 684

        -- GADT instance declaration
        | data_or_newtype tycl_hdr opt_kind_sig 
685
		 gadt_constrlist
686
		 deriving
687 688
		{% mkTyData (comb4 $1 $2 $4 $5) (unLoc $1) True $2 
		   	    (unLoc $3) (unLoc $4) (unLoc $5) }
689

690 691 692 693
data_or_newtype :: { Located NewOrData }
	: 'data'	{ L1 DataType }
	| 'newtype'	{ L1 NewType }

694 695 696
opt_kind_sig :: { Located (Maybe Kind) }
	: 				{ noLoc Nothing }
	| '::' kind			{ LL (Just (unLoc $2)) }
697

698
-- tycl_hdr parses the header of a class or data type decl,
699 700 701 702
-- which takes the form
--	T a b
-- 	Eq a => T a
--	(Eq a, Ord b) => T a b
703
--      T Int [a]			-- for associated types
704
-- Rather a lot of inlining here, else we get reduce/reduce errors
705 706 707
tycl_hdr :: { Located (Maybe (LHsContext RdrName), LHsType RdrName) }
	: context '=>' type		{ LL (Just $1, $3) }
	| type                          { L1 (Nothing, $1) }
708

709 710 711 712 713
-----------------------------------------------------------------------------
-- Stand-alone deriving

-- Glasgow extension: stand-alone deriving declarations
stand_alone_deriving :: { LDerivDecl RdrName }
714
  	: 'deriving' 'instance' inst_type { LL (DerivDecl $3) }
715

716 717 718
-----------------------------------------------------------------------------
-- Nested declarations

719
-- Declaration in class bodies
720
--
721 722 723 724 725 726 727 728 729
decl_cls  :: { Located (OrdList (LHsDecl RdrName)) }
decl_cls  : at_decl_cls		        { LL (unitOL (L1 (TyClD (unLoc $1)))) }
	  | decl                        { $1 }

decls_cls :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
	  : decls_cls ';' decl_cls	{ LL (unLoc $1 `appOL` unLoc $3) }
	  | decls_cls ';'		{ LL (unLoc $1) }
	  | decl_cls			{ $1 }
	  | {- empty -}			{ noLoc nilOL }
730 731


732
decllist_cls
733
        :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
734 735
	: '{'         decls_cls '}'	{ LL (unLoc $2) }
	|     vocurly decls_cls close	{ $2 }
736

737
-- Class body
738
--
739
where_cls :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
740 741
				-- No implicit parameters
				-- May have type declarations
742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767
	: 'where' decllist_cls	        { LL (unLoc $2) }
	| {- empty -}		        { noLoc nilOL }

-- Declarations in instance bodies
--
decl_inst  :: { Located (OrdList (LHsDecl RdrName)) }
decl_inst  : at_decl_inst	        { LL (unitOL (L1 (TyClD (unLoc $1)))) }
	   | decl                       { $1 }

decls_inst :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
	   : decls_inst ';' decl_inst	{ LL (unLoc $1 `appOL` unLoc $3) }
	   | decls_inst ';'		{ LL (unLoc $1) }
	   | decl_inst			{ $1 }
	   | {- empty -}		{ noLoc nilOL }

decllist_inst 
        :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
	: '{'         decls_inst '}'	{ LL (unLoc $2) }
	|     vocurly decls_inst close	{ $2 }

-- Instance body
--
where_inst :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
				-- No implicit parameters
				-- May have type declarations
	: 'where' decllist_inst		{ LL (unLoc $2) }
768 769
	| {- empty -}			{ noLoc nilOL }

770 771
-- Declarations in binding groups other than classes and instances
--
772
decls 	:: { Located (OrdList (LHsDecl RdrName)) }	
Ian Lynagh's avatar
Ian Lynagh committed
773 774
	: decls ';' decl		{ let { this = unLoc $3;
                                    rest = unLoc $1;
Ian Lynagh's avatar
Ian Lynagh committed
775
                                    these = rest `appOL` this }
Ian Lynagh's avatar
Ian Lynagh committed
776 777
                              in rest `seq` this `seq` these `seq`
                                    LL these }
778
	| decls ';'			{ LL (unLoc $1) }
779
	| decl				{ $1 }
780
	| {- empty -}			{ noLoc nilOL }
781

782
decllist :: { Located (OrdList (LHsDecl RdrName)) }
783 784 785
	: '{'            decls '}'	{ LL (unLoc $2) }
	|     vocurly    decls close	{ $2 }

786 787
-- Binding groups other than those of class and instance declarations
--
788
binds 	::  { Located (HsLocalBinds RdrName) } 		-- May have implicit parameters
789
						-- No type declarations
790
	: decllist			{ L1 (HsValBinds (cvBindGroup (unLoc $1))) }
791 792
	| '{'            dbinds '}'	{ LL (HsIPBinds (IPBinds (unLoc $2) emptyTcEvBinds)) }
	|     vocurly    dbinds close	{ L (getLoc $2) (HsIPBinds (IPBinds (unLoc $2) emptyTcEvBinds)) }
793

794
wherebinds :: { Located (HsLocalBinds RdrName) }	-- May have implicit parameters
795
						-- No type declarations
796
	: 'where' binds			{ LL (unLoc $2) }
797
	| {- empty -}			{ noLoc emptyLocalBinds }
798 799 800 801 802


-----------------------------------------------------------------------------
-- Transformation Rules

803
rules	:: { OrdList (LHsDecl RdrName) }
804
	:  rules ';' rule			{ $1 `snocOL` $3 }
805
        |  rules ';'				{ $1 }
806 807
        |  rule					{ unitOL $1 }
	|  {- empty -}				{ nilOL }
808

809
rule  	:: { LHsDecl RdrName }
810
	: STRING activation rule_forall infixexp '=' exp
811 812
	     { LL $ RuleD (HsRule (getSTRING $1) 
				  ($2 `orElse` AlwaysActive) 
813
				  $3 $4 placeHolderNames $6 placeHolderNames) }
814

815 816 817
activation :: { Maybe Activation } 
        : {- empty -}                           { Nothing }
        | explicit_activation                   { Just $1 }
818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835

explicit_activation :: { Activation }  -- In brackets
        : '[' INTEGER ']'		{ ActiveAfter  (fromInteger (getINTEGER $2)) }
        | '[' '~' INTEGER ']'		{ ActiveBefore (fromInteger (getINTEGER $3)) }

rule_forall :: { [RuleBndr RdrName] }
	: 'forall' rule_var_list '.'            { $2 }
        | {- empty -}				{ [] }

rule_var_list :: { [RuleBndr RdrName] }
        : rule_var				{ [$1] }
        | rule_var rule_var_list		{ $1 : $2 }

rule_var :: { RuleBndr RdrName }
	: varid                              	{ RuleBndr $1 }
       	| '(' varid '::' ctype ')'             	{ RuleBndrSig $2 $4 }

-----------------------------------------------------------------------------
Ian Lynagh's avatar
Ian Lynagh committed
836 837 838 839 840 841 842 843 844 845
-- Warnings and deprecations (c.f. rules)

warnings :: { OrdList (LHsDecl RdrName) }
	: warnings ';' warning		{ $1 `appOL` $3 }
	| warnings ';' 			{ $1 }
	| warning				{ $1 }
	| {- empty -}				{ nilOL }

-- SUP: TEMPORARY HACK, not checking for `module Foo'
warning :: { OrdList (LHsDecl RdrName) }
846 847
	: namelist strings
		{ toOL [ LL $ WarningD (Warning n (WarningTxt $ unLoc $2))
Ian Lynagh's avatar
Ian Lynagh committed
848
		       | n <- unLoc $1 ] }
849

850
deprecations :: { OrdList (LHsDecl RdrName) }
851
	: deprecations ';' deprecation		{ $1 `appOL` $3 }
852
	| deprecations ';' 			{ $1 }
853 854
	| deprecation				{ $1 }
	| {- empty -}				{ nilOL }
855 856

-- SUP: TEMPORARY HACK, not checking for `module Foo'
857
deprecation :: { OrdList (LHsDecl RdrName) }
858 859
	: namelist strings
		{ toOL [ LL $ WarningD (Warning n (DeprecatedTxt $ unLoc $2))
860
		       | n <- unLoc $1 ] }
861

862 863 864 865 866 867 868 869
strings :: { Located [FastString] }
    : STRING { L1 [getSTRING $1] }
    | '[' stringlist ']' { LL $ fromOL (unLoc $2) }

stringlist :: { Located (OrdList FastString) }
    : stringlist ',' STRING { LL (unLoc $1 `snocOL` getSTRING $3) }
    | STRING                { LL (unitOL (getSTRING $1)) }

870 871 872 873 874 875 876
-----------------------------------------------------------------------------
-- Annotations
annotation :: { LHsDecl RdrName }
    : '{-# ANN' name_var aexp '#-}'      { LL (AnnD $ HsAnnotation (ValueAnnProvenance (unLoc $2)) $3) }
    | '{-# ANN' 'type' tycon aexp '#-}'  { LL (AnnD $ HsAnnotation (TypeAnnProvenance (unLoc $3)) $4) }
    | '{-# ANN' 'module' aexp '#-}'      { LL (AnnD $ HsAnnotation ModuleAnnProvenance $3) }

877 878 879 880 881

-----------------------------------------------------------------------------
-- Foreign import and export declarations

fdecl :: { LHsDecl RdrName }
Simon Marlow's avatar
Simon Marlow committed
882
fdecl : 'import' callconv safety fspec
883
		{% mkImport $2 $3 (unLoc $4) >>= return.LL }
Simon Marlow's avatar
Simon Marlow committed
884
      | 'import' callconv        fspec		
885 886 887 888 889
		{% do { d <- mkImport $2 (PlaySafe False) (unLoc $3);
			return (LL d) } }
      | 'export' callconv fspec
		{% mkExport $2 (unLoc $3) >>= return.LL }

890 891 892 893
callconv :: { CCallConv }
	  : 'stdcall'			{ StdCallConv }
	  | 'ccall'			{ CCallConv   }
	  | 'prim'			{ PrimCallConv}
894 895 896 897

safety :: { Safety }
	: 'unsafe'			{ PlayRisky }
	| 'safe'			{ PlaySafe  False }
898
	| 'interruptible'		{ PlayInterruptible }
899
	| 'threadsafe'			{ PlaySafe  True } -- deprecated alias
900 901

fspec :: { Located (Located FastString, Located RdrName, LHsType RdrName) }
902 903
       : STRING var '::' sigtypedoc     { LL (L (getLoc $1) (getSTRING $1), $2, $4) }
       |        var '::' sigtypedoc     { LL (noLoc nilFS, $1, $3) }
904 905 906 907 908 909 910 911 912 913 914 915 916 917 918
         -- if the entity string is missing, it defaults to the empty string;
         -- the meaning of an empty entity string depends on the calling
         -- convention

-----------------------------------------------------------------------------
-- Type signatures

opt_sig :: { Maybe (LHsType RdrName) }
	: {- empty -}			{ Nothing }
	| '::' sigtype			{ Just $2 }

opt_asig :: { Maybe (LHsType RdrName) }
	: {- empty -}			{ Nothing }
	| '::' atype			{ Just $2 }

919 920
sigtype :: { LHsType RdrName }		-- Always a HsForAllTy,
                                        -- to tell the renamer where to generalise
921 922 923
	: ctype				{ L1 (mkImplicitHsForAllTy (noLoc []) $1) }
	-- Wrap an Implicit forall if there isn't one there already

924
sigtypedoc :: { LHsType RdrName }       -- Always a HsForAllTy
925 926 927
	: ctypedoc			{ L1 (mkImplicitHsForAllTy (noLoc []) $1) }
	-- Wrap an Implicit forall if there isn't one there already

928 929 930 931
sig_vars :: { Located [Located RdrName] }
	 : sig_vars ',' var		{ LL ($3 : unLoc $1) }
	 | var				{ L1 [$1] }

932 933 934 935
sigtypes1 :: { [LHsType RdrName] }	-- Always HsForAllTys
	: sigtype			{ [ $1 ] }
	| sigtype ',' sigtypes1		{ $1 : $3 }

936 937 938
-----------------------------------------------------------------------------
-- Types

939
infixtype :: { LHsType RdrName }
waern's avatar
waern committed
940 941
	: btype qtyconop type         { LL $ HsOpTy $1 $2 $3 }
        | btype tyvarop  type  	 { LL $ HsOpTy $1 $2 $3 }
942

943 944
strict_mark :: { Located HsBang }
	: '!'				{ L1 HsStrict }
945
	| '{-# UNPACK' '#-}' '!'	{ LL HsUnpack }
946

947 948 949
-- A ctype is a for-all type
ctype	:: { LHsType RdrName }
	: 'forall' tv_bndrs '.' ctype	{ LL $ mkExplicitHsForAllTy $2 (noLoc []) $4 }
waern's avatar
waern committed
950
	| context '=>' ctype		{ LL $ mkImplicitHsForAllTy   $1 $3 }
951
	-- A type of form (context => type) is an *implicit* HsForAllTy
waern's avatar
waern committed
952 953
	| ipvar '::' type		{ LL (HsPredTy (HsIParam (unLoc $1) $3)) }
	| type  			{ $1 }
954

955 956 957 958 959 960 961 962 963 964 965
----------------------
-- Notes for 'ctypedoc'
-- It would have been nice to simplify the grammar by unifying `ctype` and 
-- ctypedoc` into one production, allowing comments on types everywhere (and
-- rejecting them after parsing, where necessary).  This is however not possible
-- since it leads to ambiguity. The reason is the support for comments on record
-- fields: 
--         data R = R { field :: Int -- ^ comment on the field }
-- If we allow comments on types here, it's not clear if the comment applies
-- to 'field' or to 'Int'. So we must use `ctype` to describe the type.

966 967 968 969
ctypedoc :: { LHsType RdrName }
	: 'forall' tv_bndrs '.' ctypedoc	{ LL $ mkExplicitHsForAllTy $2 (noLoc []) $4 }
	| context '=>' ctypedoc		{ LL $ mkImplicitHsForAllTy   $1 $3 }
	-- A type of form (context => type) is an *implicit* HsForAllTy
waern's avatar
waern committed
970 971
	| ipvar '::' type		{ LL (HsPredTy (HsIParam (unLoc $1) $3)) }
	| typedoc			{ $1 }
972

973 974
----------------------
-- Notes for 'context'
975 976 977 978
-- We parse a context as a btype so that we don't get reduce/reduce
-- errors in ctype.  The basic problem is that
--	(Eq a, Ord a)
-- looks so much like a tuple type.  We can't tell until we find the =>
979

waern's avatar
waern committed
980
-- We have the t1 ~ t2 form both in 'context' and in type, 
981 982 983
-- to permit an individual equational constraint without parenthesis.
-- Thus for some reason we allow    f :: a~b => blah
-- but not 	                    f :: ?x::Int => blah
984
context :: { LHsContext RdrName }
985 986 987
        : btype '~'      btype  	{% checkContext
					     (LL $ HsPredTy (HsEqualP $1 $3)) }
	| btype 			{% checkContext $1 }
988

waern's avatar
waern committed
989
type :: { LHsType RdrName }
990
        : btype                         { $1 }
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
991
        | btype qtyconop type           { LL $ HsOpTy $1 $2 $3 }
waern's avatar
waern committed
992
        | btype tyvarop  type     	{ LL $ HsOpTy $1 $2 $3 }
993
 	| btype '->'     ctype		{ LL $ HsFunTy $1 $3 }
994
        | btype '~'      btype  	{ LL $ HsPredTy (HsEqualP $1 $3) }
995

waern's avatar
waern committed
996
typedoc :: { LHsType RdrName }
997 998
        : btype                          { $1 }
        | btype docprev                  { LL $ HsDocTy $1 $2 }
waern's avatar
waern committed
999 1000 1001 1002
        | btype qtyconop type            { LL $ HsOpTy $1 $2 $3 }
        | btype qtyconop type docprev    { LL $ HsDocTy (L (comb3 $1 $2 $3) (HsOpTy $1 $2 $3)) $4 }
        | btype tyvarop  type            { LL $ HsOpTy $1 $2 $3 }
        | btype tyvarop  type docprev    { LL $ HsDocTy (L (comb3 $1 $2 $3) (HsOpTy $1 $2 $3)) $4 }
1003 1004 1005 1006
        | btype '->'     ctypedoc        { LL $ HsFunTy $1 $3 }
        | btype docprev '->' ctypedoc    { LL $ HsFunTy (L (comb2 $1 $2) (HsDocTy $1 $2)) $4 }
        | btype '~'      btype           { LL $ HsPredTy (HsEqualP $1 $3) }

1007 1008 1009 1010 1011 1012
btype :: { LHsType RdrName }
	: btype atype			{ LL $ HsAppTy $1 $2 }
	| atype				{ $1 }

atype :: { LHsType RdrName }
	: gtycon			{ L1 (HsTyVar (unLoc $1)) }
1013
	| tyvar				{ L1 (HsTyVar (unLoc $1)) }
1014 1015
	| strict_mark atype		{ LL (HsBangTy (unLoc $1) $2) }  -- Constructor sigs only
	| '{' fielddecls '}'		{ LL $ HsRecTy $2 }              -- Constructor sigs only
1016
	| '(' ctype ',' comma_types1 ')'  { LL $ HsTupleTy Boxed  ($2:$4) }
1017
	| '(#' comma_types1 '#)'	{ LL $ HsTupleTy Unboxed $2     }
1018 1019
	| '[' ctype ']'			{ LL $ HsListTy  $2 }
	| '[:' ctype ':]'		{ LL $ HsPArrTy  $2 }
1020
	| '(' ctype ')'		        { LL $ HsParTy   $2 }
1021
	| '(' ctype '::' kind ')'	{ LL $ HsKindSig $2 (unLoc $4) }
1022
	| quasiquote       	        { L1 (HsQuasiQuoteTy (unLoc $1)) }
1023 1024 1025
	| '$(' exp ')'	      		{ LL $ mkHsSpliceTy $2 }
	| TH_ID_SPLICE	      		{ LL $ mkHsSpliceTy $ L1 $ HsVar $ 
					  mkUnqual varName (getTH_ID_SPLICE $1) }
1026 1027 1028 1029 1030 1031 1032 1033
-- Generics
        | INTEGER                       { L1 (HsNumTy (getINTEGER $1)) }

-- An inst_type is what occurs in the head of an instance decl
--	e.g.  (Foo a, Gaz b) => Wibble a b
-- It's kept as a single type, with a MonoDictTy at the right
-- hand corner, for convenience.
inst_type :: { LHsType RdrName }
1034
	: sigtype			{% checkInstType $1 }
1035

1036 1037 1038 1039
inst_types1 :: { [LHsType RdrName] }
	: inst_type			{ [$1] }
	| inst_type ',' inst_types1	{ $1 : $3 }

1040 1041 1042 1043 1044
comma_types0  :: { [LHsType RdrName] }
	: comma_types1			{ $1 }
	| {- empty -}			{ [] }

comma_types1	:: { [LHsType RdrName] }
1045 1046
	: ctype				{ [$1] }
	| ctype  ',' comma_types1	{ $1 : $3 }
1047 1048 1049 1050 1051 1052

tv_bndrs :: { [LHsTyVarBndr RdrName] }
	 : tv_bndr tv_bndrs		{ $1 : $2 }
	 | {- empty -}			{ [] }

tv_bndr :: { LHsTyVarBndr RdrName }
1053
	: tyvar				{ L1 (UserTyVar (unLoc $1) placeHolderKind) }
1054 1055
	| '(' tyvar '::' kind ')'	{ LL (KindedTyVar (unLoc $2) 
							  (unLoc $4)) }
1056

1057
fds :: { Located [Located (FunDep RdrName)] }
1058 1059 1060
	: {- empty -}			{ noLoc [] }
	| '|' fds1			{ LL (reverse (unLoc $2)) }

1061
fds1 :: { Located [Located (FunDep RdrName)] }
1062 1063 1064
	: fds1 ',' fd			{ LL ($3 : unLoc $1) }
	| fd				{ L1 [$1] }

1065
fd :: { Located (FunDep RdrName) }
1066 1067 1068 1069 1070 1071 1072 1073 1074 1075
	: varids0 '->' varids0		{ L (comb3 $1 $2 $3)
					   (reverse (unLoc $1), reverse (unLoc $3)) }

varids0	:: { Located [RdrName] }
	: {- empty -}			{ noLoc [] }
	| varids0 tyvar			{ LL (unLoc $2 : unLoc $1) }

-----------------------------------------------------------------------------
-- Kinds

1076
kind	:: { Located Kind }
1077
	: akind			{ $1 }
1078
	| akind '->' kind	{ LL (mkArrowKind (unLoc $1) (unLoc $3)) }
1079

1080 1081 1082 1083
akind	:: { Located Kind }
	: '*'			{ L1 liftedTypeKind }
	| '!'			{ L1 unliftedTypeKind }
	| '(' kind ')'		{ LL (unLoc $2) }
1084 1085 1086 1087 1088


-----------------------------------------------------------------------------
-- Datatype declarations

1089 1090 1091 1092
gadt_constrlist :: { Located [LConDecl RdrName] }	-- Returned in order
	: 'where' '{'        gadt_constrs '}'      { L (comb2 $1 $3) (unLoc $3) }
	| 'where' vocurly    gadt_constrs close	   { L (comb2 $1 $3) (unLoc $3) }
	| {- empty -}                              { noLoc [] }
1093 1094

gadt_constrs :: { Located [LConDecl RdrName] }
1095 1096 1097
        : gadt_constr ';' gadt_constrs  { L (comb2 (head $1) $3) ($1 ++ unLoc $3) }
        | gadt_constr                   { L (getLoc (head $1)) $1 }
        | {- empty -}	 		{ noLoc [] }
1098

1099 1100 1101 1102 1103 1104
-- We allow the following forms:
--	C :: Eq a => a -> T a
--	C :: forall a. Eq a => !a -> T a
--	D { x,y :: a } :: T a
--	forall a. Eq a => D { x,y :: a } :: T a

1105
gadt_constr :: { [LConDecl RdrName] }	-- Returns a list because of:   C,D :: ty
1106 1107
        : con_list '::' sigtype
                { map (sL (comb2 $1 $3)) (mkGadtDecl (unLoc $1) $3) } 
1108

1109 1110 1111 1112
		-- Deprecated syntax for GADT record declarations
	| oqtycon '{' fielddecls '}' '::' sigtype
		{% do { cd <- mkDeprecatedGadtRecordDecl (comb2 $1 $6) $1 $3 $6
                      ; return [cd] } }
1113 1114

constrs :: { Located [LConDecl RdrName] }
1115
        : maybe_docnext '=' constrs1    { L (comb2 $2 $3) (addConDocs (unLoc $3) $1) }
1116 1117

constrs1 :: { Located [LConDecl RdrName] }
1118 1119
	: constrs1 maybe_docnext '|' maybe_docprev constr { LL (addConDoc $5 $2 : addConDocFirst (unLoc $1) $4) }
	| constr			                  { L1 [$1] }
1120 1121

constr :: { LConDecl RdrName }
1122 1123
	: maybe_docnext forall context '=>' constr_stuff maybe_docprev	
		{ let (con,details) = unLoc $5 in 
1124 1125
		  addConDoc (L (comb4 $2 $3 $4 $5) (mkSimpleConDecl con (unLoc $2) $3 details))
                            ($1 `mplus` $6) }
1126 1127
	| maybe_docnext forall constr_stuff maybe_docprev
		{ let (con,details) = unLoc $3 in 
1128 1129
		  addConDoc (L (comb2 $2 $3) (mkSimpleConDecl con (unLoc $2) (noLoc []) details))
                            ($1 `mplus` $4) }
1130 1131 1132 1133 1134

forall :: { Located [LHsTyVarBndr RdrName] }
	: 'forall' tv_bndrs '.'		{ LL $2 }
	| {- empty -}			{ noLoc [] }

1135
constr_stuff :: { Located (Located RdrName, HsConDeclDetails RdrName) }
1136 1137 1138 1139 1140 1141 1142
-- We parse the constructor declaration 
--	C t1 t2
-- as a btype (treating C as a type constructor) and then convert C to be
-- a data constructor.  Reason: it might continue like this:
--	C t1 t2 %: D Int
-- in which case C really would be a type constructor.  We can't resolve this
-- ambiguity till we come across the constructor oprerator :% (or not, more usually)
1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158
	: btype				{% splitCon $1 >>= return.LL }
	| btype conop btype		{  LL ($2, InfixCon $1 $3) }

fielddecls :: { [ConDeclField RdrName] }
        : {- empty -}     { [] }
        | fielddecls1     { $1 }

fielddecls1 :: { [ConDeclField RdrName] }
	: fielddecl maybe_docnext ',' maybe_docprev fielddecls1
                      { [ addFieldDoc f $4 | f <- $1 ] ++ addFieldDocs $5 $2 }
                             -- This adds the doc $4 to each field separately
	| fielddecl   { $1 }

fielddecl :: { [ConDeclField RdrName] }    -- A list because of   f,g :: Int
	: maybe_docnext sig_vars '::' ctype maybe_docprev      { [ ConDeclField fld $4 ($1 `mplus` $5) 
                                                                 | fld <- reverse (unLoc $2) ] }
1159

1160 1161 1162 1163
-- We allow the odd-looking 'inst_type' in a deriving clause, so that
-- we can do deriving( forall a. C [a] ) in a newtype (GHC extension).
-- The 'C [a]' part is converted to an HsPredTy by checkInstType
-- We don't allow a context, but that's sorted out by the type checker.
1164 1165
deriving :: { Located (Maybe [LHsType RdrName]) }
	: {- empty -}				{ noLoc Nothing }
1166 1167 1168
	| 'deriving' qtycon	{% do { let { L loc tv = $2 }
				      ; p <- checkInstType (L loc (HsTyVar tv))
				      ; return (LL (Just [p])) } }
1169 1170
	| 'deriving' '(' ')'	 		{ LL (Just []) }
	| 'deriving' '(' inst_types1 ')' 	{ LL (Just $3) }
1171 1172 1173 1174 1175 1176
             -- Glasgow extension: allow partial 
             -- applications in derivings

-----------------------------------------------------------------------------
-- Value definitions

simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
1177 1178 1179
{- Note [Declaration/signature overlap]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
There's an awkward overlap with a type signature.  Consider
1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198
	f :: Int -> Int = ...rhs...
   Then we can't tell whether it's a type signature or a value
   definition with a result signature until we see the '='.
   So we have to inline enough to postpone reductions until we know.
-}

{-
  ATTENTION: Dirty Hackery Ahead! If the second alternative of vars is var
  instead of qvar, we get another shift/reduce-conflict. Consider the
  following programs:
  
     { (^^) :: Int->Int ; }          Type signature; only var allowed

     { (^^) :: Int->Int = ... ; }    Value defn with result signature;
				     qvar allowed (because of instance decls)
  
  We can't tell whether to reduce var to qvar until after we've read the signatures.
-}

1199 1200 1201
docdecl :: { LHsDecl RdrName }
        : docdecld { L1 (DocD (unLoc $1)) }

1202
docdecld :: { LDocDecl }
1203 1204 1205 1206 1207
        : docnext                               { L1 (DocCommentNext (unLoc $1)) }
        | docprev                               { L1 (DocCommentPrev (unLoc $1)) }
        | docnamed                              { L1 (case (unLoc $1) of (n, doc) -> DocCommentNamed n doc) }
        | docsection                            { L1 (case (unLoc $1) of (n, doc) -> DocGroup n doc) }

1208
decl 	:: { Located (OrdList (LHsDecl RdrName)) }
1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222
	: sigdecl		{ $1 }

        | '!' aexp rhs          {% do { let { e = LL (SectionR (LL (HsVar bang_RDR)) $2) };
                                        pat <