Parser.y.pp 50.1 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
module Parser ( parseModule, parseStmt, parseIdentifier, parseType,
12
		parseHeader ) where
13 14 15 16 17 18

#define INCLUDE #include 
INCLUDE "HsVersions.h"

import HsSyn
import RdrHsSyn
19
import HscTypes		( IsBootInterface, DeprecTxt )
20 21 22 23 24
import Lexer
import RdrName
import TysWiredIn	( unitTyCon, unitDataCon, tupleTyCon, tupleCon, nilDataCon,
			  listTyCon_RDR, parrTyCon_RDR, consDataCon_RDR )
import Type		( funTyCon )
25
import ForeignCall	( Safety(..), CExportSpec(..), CLabelString,
26 27
			  CCallConv(..), CCallTarget(..), defaultCCallConv
			)
28
import OccName		( varName, dataName, tcClsName, tvName )
29 30
import DataCon		( DataCon, dataConName )
import SrcLoc		( Located(..), unLoc, getLoc, noLoc, combineSrcSpans,
31 32
			  SrcSpan, combineLocs, srcLocFile, 
			  mkSrcLoc, mkSrcSpan )
33
import Module
34
import StaticFlags	( opt_SccProfilingOn )
Simon Marlow's avatar
Simon Marlow committed
35
import Type		( Kind, mkArrowKind, liftedTypeKind, unliftedTypeKind )
36
import BasicTypes	( Boxity(..), Fixity(..), FixityDirection(..), IPName(..),
37
			  Activation(..), defaultInlineSpec )
38
import OrdList
39 40 41 42

import FastString
import Maybes		( orElse )
import Outputable
43
import GLAEXTS
44 45 46 47
}

{-
-----------------------------------------------------------------------------
48
Conflicts: 36 shift/reduce (1.25)
49

50
10 for abiguity in 'if x then y else z + 1'		[State 178]
51 52 53
	(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

54
1 for ambiguity in 'if x then y else z :: T'		[State 178]
55 56
	(shift parses as 'if x then y else (z :: T)', as per longest-parse rule)

57
4 for ambiguity in 'if x then y else z -< e'		[State 178]
ross's avatar
ross committed
58
	(shift parses as 'if x then y else (z -< T)', as per longest-parse rule)
59 60 61 62 63 64 65 66 67 68
	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 ...
ross's avatar
ross committed
69

70
10 for ambiguity in 'e :: a `b` c'.  Does this mean 	[States 11, 253]
71 72
	(e::a) `b` c, or 
	(e :: (a `b` c))
73
    As well as `b` we can have !, VARSYM, QCONSYM, and CONSYM, hence 5 cases
74
    Same duplication between states 11 and 253 as the previous case
75

76
1 for ambiguity in 'let ?x ...'				[State 329]
77 78 79 80
	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.

81
1 for ambiguity in '{-# RULES "name" [ ... #-}		[State 382]
82 83 84 85
	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

86
1 for ambiguity in '{-# RULES "name" forall = ... #-}' 	[State 474]
87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181
	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'.

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

   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 }
 '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

 'forall'	{ L _ ITforall }			-- GHC extension keywords
 'foreign'	{ L _ ITforeign }
 'export'	{ L _ ITexport }
 'label'	{ L _ ITlabel } 
 'dynamic'	{ L _ ITdynamic }
 'safe'		{ L _ ITsafe }
 'threadsafe'	{ L _ ITthreadsafe }
 'unsafe'	{ L _ ITunsafe }
 'mdo'		{ L _ ITmdo }
 'stdcall'      { L _ ITstdcallconv }
 'ccall'        { L _ ITccallconv }
 'dotnet'       { L _ ITdotnet }
 'proc'		{ L _ ITproc }		-- for arrow notation extension
 'rec'		{ L _ ITrec }		-- for arrow notation extension

182 183 184
 '{-# INLINE'      	  { L _ (ITinline_prag _) }
 '{-# SPECIALISE'  	  { L _ ITspec_prag }
 '{-# SPECIALISE_INLINE'  { L _ (ITspec_inline_prag _) }
185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271
 '{-# SOURCE'	   { L _ ITsource_prag }
 '{-# RULES'	   { L _ ITrules_prag }
 '{-# CORE'        { L _ ITcore_prag }              -- hdaume: annotated core
 '{-# SCC'	   { L _ ITscc_prag }
 '{-# DEPRECATED'  { L _ ITdeprecated_prag }
 '{-# UNPACK'      { L _ ITunpack_prag }
 '#-}'		   { 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  _) }

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

 CHAR		{ L _ (ITchar     _) }
 STRING		{ L _ (ITstring   _) }
 INTEGER	{ L _ (ITinteger  _) }
 RATIONAL	{ L _ (ITrational _) }
		    
 PRIMCHAR	{ L _ (ITprimchar   _) }
 PRIMSTRING	{ L _ (ITprimstring _) }
 PRIMINTEGER	{ L _ (ITprimint    _) }
 PRIMFLOAT	{ L _ (ITprimfloat  _) }
 PRIMDOUBLE	{ L _ (ITprimdouble _) }
 		    
-- 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

%monad { P } { >>= } { return }
%lexer { lexer } { L _ ITeof }
%name parseModule module
%name parseStmt   maybe_stmt
%name parseIdentifier  identifier
272
%name parseType ctype
273
%partial parseHeader header
274
%tokentype { (Located Token) }
275 276
%%

277 278 279 280 281 282 283 284
-----------------------------------------------------------------------------
-- Identifiers; one of the entry points
identifier :: { Located RdrName }
	: qvar				{ $1 }
	| qcon				{ $1 }
	| qvarop			{ $1 }
	| qconop			{ $1 }

285 286 287 288 289 290 291 292 293 294 295 296 297
-----------------------------------------------------------------------------
-- 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) }
 	: 'module' modid maybemoddeprec maybeexports 'where' body 
		{% fileSrcSpan >>= \ loc ->
298
		   return (L loc (HsModule (Just $2) $4 (fst $6) (snd $6) $3)) }
299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322
	| missing_module_keyword top close
		{% fileSrcSpan >>= \ loc ->
		   return (L loc (HsModule Nothing Nothing 
				(fst $2) (snd $2) Nothing)) }

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

maybemoddeprec :: { Maybe DeprecTxt }
	: '{-# DEPRECATED' STRING '#-}' 	{ Just (getSTRING $2) }
	|  {- empty -}				{ Nothing }

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

top 	:: { ([LImportDecl RdrName], [LHsDecl RdrName]) }
	: importdecls				{ (reverse $1,[]) }
	| importdecls ';' cvtopdecls		{ (reverse $1,$3) }
	| cvtopdecls				{ ([],$1) }

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

323 324 325 326 327 328 329 330 331 332 333 334 335 336 337
-----------------------------------------------------------------------------
-- Module declaration & imports only

header 	:: { Located (HsModule RdrName) }
 	: 'module' modid maybemoddeprec maybeexports 'where' header_body
		{% fileSrcSpan >>= \ loc ->
		   return (L loc (HsModule (Just $2) $4 $6 [] $3)) }
	| missing_module_keyword importdecls
		{% fileSrcSpan >>= \ loc ->
		   return (L loc (HsModule Nothing Nothing $2 [] Nothing)) }

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

338 339 340 341 342 343 344
-----------------------------------------------------------------------------
-- The Export List

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

345 346 347 348 349
exportlist  :: { [LIE RdrName] }
	: ','					{ [] }
	| exportlist1				{ $1 }

exportlist1 :: { [LIE RdrName] }
350 351
	:  export				{ [$1] }
	|  export ',' exportlist		{ $1 : $3 }
352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369
	|  {- empty -}				{ [] }

   -- 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] }
	:  qcnames ',' qcname			{ unLoc $3 : $1 }
	|  qcname				{ [unLoc $1]  }

qcname 	:: { Located RdrName }	-- Variable or data constructor
	:  qvar					{ $1 }
370
	|  qcon					{ $1 }
371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395

-----------------------------------------------------------------------------
-- 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 }
	: 'import' maybe_src optqualified modid maybeas maybeimpspec 
		{ L (comb4 $1 $4 $5 $6) (ImportDecl $4 $2 $3 (unLoc $5) (unLoc $6)) }

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

optqualified :: { Bool }
      	: 'qualified'                           { True  }
      	| {- empty -}				{ False }

Simon Marlow's avatar
Simon Marlow committed
396
maybeas :: { Located (Maybe ModuleName) }
397 398 399 400 401 402 403 404
      	: '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]) }
405 406
	:  '(' exportlist ')'  			{ LL (False, $2) }
	|  'hiding' '(' exportlist ')' 		{ LL (True,  $3) }
407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426

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

427
topdecls :: { OrdList (LHsDecl RdrName) }
428
	: topdecls ';' topdecl		{ $1 `appOL` $3 }
429
	| topdecls ';'			{ $1 }
430
	| topdecl			{ $1 }
431

432 433
topdecl :: { OrdList (LHsDecl RdrName) }
  	: tycl_decl			{ unitOL (L1 (TyClD (unLoc $1))) }
434 435
	| 'instance' inst_type where
		{ let (binds,sigs) = cvBindsAndSigs (unLoc $3)
436 437 438 439 440
		  in unitOL (L (comb3 $1 $2 $3) (InstD (InstDecl $2 binds sigs))) }
	| 'default' '(' comma_types0 ')'	{ unitOL (LL $ DefD (DefaultDecl $3)) }
	| 'foreign' fdecl			{ unitOL (LL (unLoc $2)) }
	| '{-# DEPRECATED' deprecations '#-}'	{ $2 }
	| '{-# RULES' rules '#-}'		{ $2 }
441 442
      	| decl					{ unLoc $1 }

443 444 445 446 447 448
	-- Template Haskell Extension
	| '$(' exp ')'				{ unitOL (LL $ SpliceD (SpliceDecl $2)) }
	| TH_ID_SPLICE				{ unitOL (LL $ SpliceD (SpliceDecl $
							L1 $ HsVar (mkUnqual varName (getTH_ID_SPLICE $1))
						  )) }

449
tycl_decl :: { LTyClDecl RdrName }
450 451 452 453 454
 	: 'type' type '=' ctype	
		-- Note type on the left of the '='; this allows
		-- infix type constructors to be declared
		-- 
		-- Note ctype, not sigtype, on the right
455 456 457
		-- 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
458 459
 		{% do { (tc,tvs) <- checkSynHdr $2
		      ; return (LL (TySynonym tc tvs $4)) } }
460

461
	| data_or_newtype tycl_hdr constrs deriving
462 463
		{ L (comb4 $1 $2 $3 $4)	-- We need the location on tycl_hdr 
					-- in case constrs and deriving are both empty
464
		    (mkTyData (unLoc $1) (unLoc $2) Nothing (reverse (unLoc $3)) (unLoc $4)) }
465

466
        | data_or_newtype tycl_hdr opt_kind_sig 
467
		 'where' gadt_constrlist
468
		 deriving
469
		{ L (comb4 $1 $2 $4 $5)
470
		    (mkTyData (unLoc $1) (unLoc $2) $3 (reverse (unLoc $5)) (unLoc $6)) }
471 472 473 474 475 476 477 478

	| 'class' tycl_hdr fds where
		{ let 
			(binds,sigs) = cvBindsAndSigs (unLoc $4)
		  in
	 	  L (comb4 $1 $2 $3 $4) (mkClassDecl (unLoc $2) (unLoc $3) sigs 
					  binds) }

479 480 481 482
data_or_newtype :: { Located NewOrData }
	: 'data'	{ L1 DataType }
	| 'newtype'	{ L1 NewType }

483 484 485 486
opt_kind_sig :: { Maybe Kind }
	: 				{ Nothing }
	| '::' kind			{ Just $2 }

487 488 489 490 491 492 493
-- tycl_hdr parses the header of a type or class decl,
-- which takes the form
--	T a b
-- 	Eq a => T a
--	(Eq a, Ord b) => T a b
-- Rather a lot of inlining here, else we get reduce/reduce errors
tycl_hdr :: { Located (LHsContext RdrName, Located RdrName, [LHsTyVarBndr RdrName]) }
494
	: context '=>' type		{% checkTyClHdr $1         $3 >>= return.LL }
495 496 497 498 499
	| type				{% checkTyClHdr (noLoc []) $1 >>= return.L1 }

-----------------------------------------------------------------------------
-- Nested declarations

500
decls 	:: { Located (OrdList (LHsDecl RdrName)) }	
501
	: decls ';' decl		{ LL (unLoc $1 `appOL` unLoc $3) }
502
	| decls ';'			{ LL (unLoc $1) }
503
	| decl				{ $1 }
504
	| {- empty -}			{ noLoc nilOL }
505 506


507
decllist :: { Located (OrdList (LHsDecl RdrName)) }
508 509 510
	: '{'            decls '}'	{ LL (unLoc $2) }
	|     vocurly    decls close	{ $2 }

511
where 	:: { Located (OrdList (LHsDecl RdrName)) }
512 513
				-- No implicit parameters
	: 'where' decllist		{ LL (unLoc $2) }
514
	| {- empty -}			{ noLoc nilOL }
515

516 517 518 519
binds 	::  { Located (HsLocalBinds RdrName) } 		-- May have implicit parameters
	: decllist			{ L1 (HsValBinds (cvBindGroup (unLoc $1))) }
	| '{'            dbinds '}'	{ LL (HsIPBinds (IPBinds (unLoc $2) emptyLHsBinds)) }
	|     vocurly    dbinds close	{ L (getLoc $2) (HsIPBinds (IPBinds (unLoc $2) emptyLHsBinds)) }
520

521
wherebinds :: { Located (HsLocalBinds RdrName) }	-- May have implicit parameters
522
	: 'where' binds			{ LL (unLoc $2) }
523
	| {- empty -}			{ noLoc emptyLocalBinds }
524 525 526 527 528


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

529
rules	:: { OrdList (LHsDecl RdrName) }
530
	:  rules ';' rule			{ $1 `snocOL` $3 }
531
        |  rules ';'				{ $1 }
532 533
        |  rule					{ unitOL $1 }
	|  {- empty -}				{ nilOL }
534

535
rule  	:: { LHsDecl RdrName }
536
	: STRING activation rule_forall infixexp '=' exp
537 538
	     { LL $ RuleD (HsRule (getSTRING $1) 
				  ($2 `orElse` AlwaysActive) 
539
				  $3 $4 placeHolderNames $6 placeHolderNames) }
540

541 542 543
activation :: { Maybe Activation } 
        : {- empty -}                           { Nothing }
        | explicit_activation                   { Just $1 }
544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563

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 }

-----------------------------------------------------------------------------
-- Deprecations (c.f. rules)

564
deprecations :: { OrdList (LHsDecl RdrName) }
565
	: deprecations ';' deprecation		{ $1 `appOL` $3 }
566
	| deprecations ';' 			{ $1 }
567 568
	| deprecation				{ $1 }
	| {- empty -}				{ nilOL }
569 570

-- SUP: TEMPORARY HACK, not checking for `module Foo'
571
deprecation :: { OrdList (LHsDecl RdrName) }
572
	: depreclist STRING
573 574
		{ toOL [ LL $ DeprecD (Deprecation n (getSTRING $2)) 
		       | n <- unLoc $1 ] }
575 576 577 578 579 580


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

fdecl :: { LHsDecl RdrName }
Simon Marlow's avatar
Simon Marlow committed
581
fdecl : 'import' callconv safety fspec
582
		{% mkImport $2 $3 (unLoc $4) >>= return.LL }
Simon Marlow's avatar
Simon Marlow committed
583
      | 'import' callconv        fspec		
584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616
		{% do { d <- mkImport $2 (PlaySafe False) (unLoc $3);
			return (LL d) } }
      | 'export' callconv fspec
		{% mkExport $2 (unLoc $3) >>= return.LL }

callconv :: { CallConv }
	  : 'stdcall'			{ CCall  StdCallConv }
	  | 'ccall'			{ CCall  CCallConv   }
	  | 'dotnet'			{ DNCall	     }

safety :: { Safety }
	: 'unsafe'			{ PlayRisky }
	| 'safe'			{ PlaySafe  False }
	| 'threadsafe'			{ PlaySafe  True }

fspec :: { Located (Located FastString, Located RdrName, LHsType RdrName) }
       : STRING var '::' sigtype      { LL (L (getLoc $1) (getSTRING $1), $2, $4) }
       |        var '::' sigtype      { LL (noLoc nilFS, $1, $3) }
         -- 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 }

617
sigtypes1 :: { [LHsType RdrName] }
618
	: sigtype			{ [ $1 ] }
619
	| sigtype ',' sigtypes1		{ $1 : $3 }
620 621 622 623 624 625 626 627 628 629 630 631

sigtype :: { LHsType RdrName }
	: ctype				{ L1 (mkImplicitHsForAllTy (noLoc []) $1) }
	-- Wrap an Implicit forall if there isn't one there already

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

-----------------------------------------------------------------------------
-- Types

632 633 634 635
strict_mark :: { Located HsBang }
	: '!'				{ L1 HsStrict }
	| '{-# UNPACK' '#-}' '!'	{ LL HsUnbox }

636 637 638 639 640 641 642 643 644 645 646 647 648 649 650
-- A ctype is a for-all type
ctype	:: { LHsType RdrName }
	: 'forall' tv_bndrs '.' ctype	{ LL $ mkExplicitHsForAllTy $2 (noLoc []) $4 }
	| context '=>' type		{ LL $ mkImplicitHsForAllTy   $1 $3 }
	-- A type of form (context => type) is an *implicit* HsForAllTy
	| type				{ $1 }

-- 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 =>
context :: { LHsContext RdrName }
	: btype 			{% checkContext $1 }

type :: { LHsType RdrName }
651
	: ipvar '::' gentype		{ LL (HsPredTy (HsIParam (unLoc $1) $3)) }
652 653 654 655 656
	| gentype			{ $1 }

gentype :: { LHsType RdrName }
        : btype                         { $1 }
        | btype qtyconop gentype        { LL $ HsOpTy $1 $2 $3 }
657
        | btype tyvarop  gentype  	{ LL $ HsOpTy $1 $2 $3 }
658
 	| btype '->' ctype		{ LL $ HsFunTy $1 $3 }
659 660 661 662 663 664 665

btype :: { LHsType RdrName }
	: btype atype			{ LL $ HsAppTy $1 $2 }
	| atype				{ $1 }

atype :: { LHsType RdrName }
	: gtycon			{ L1 (HsTyVar (unLoc $1)) }
666
	| tyvar				{ L1 (HsTyVar (unLoc $1)) }
667
	| strict_mark atype		{ LL (HsBangTy (unLoc $1) $2) }
668
	| '(' ctype ',' comma_types1 ')'  { LL $ HsTupleTy Boxed  ($2:$4) }
669
	| '(#' comma_types1 '#)'	{ LL $ HsTupleTy Unboxed $2     }
670 671
	| '[' ctype ']'			{ LL $ HsListTy  $2 }
	| '[:' ctype ':]'		{ LL $ HsPArrTy  $2 }
672 673 674 675 676 677 678 679 680 681
	| '(' ctype ')'		        { LL $ HsParTy   $2 }
	| '(' ctype '::' kind ')'	{ LL $ HsKindSig $2 $4 }
-- 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 }
682
	: sigtype			{% checkInstType $1 }
683

684 685 686 687
inst_types1 :: { [LHsType RdrName] }
	: inst_type			{ [$1] }
	| inst_type ',' inst_types1	{ $1 : $3 }

688 689 690 691 692
comma_types0  :: { [LHsType RdrName] }
	: comma_types1			{ $1 }
	| {- empty -}			{ [] }

comma_types1	:: { [LHsType RdrName] }
693 694
	: ctype				{ [$1] }
	| ctype  ',' comma_types1	{ $1 : $3 }
695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728

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

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

fds :: { Located [Located ([RdrName], [RdrName])] }
	: {- empty -}			{ noLoc [] }
	| '|' fds1			{ LL (reverse (unLoc $2)) }

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

fd :: { Located ([RdrName], [RdrName]) }
	: 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

kind	:: { Kind }
	: akind			{ $1 }
	| akind '->' kind	{ mkArrowKind $1 $3 }

akind	:: { Kind }
	: '*'			{ liftedTypeKind }
Simon Marlow's avatar
Simon Marlow committed
729
	| '!'			{ unliftedTypeKind }
730 731 732 733 734 735
	| '(' kind ')'		{ $2 }


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

736 737 738 739 740 741
gadt_constrlist :: { Located [LConDecl RdrName] }
	: '{'            gadt_constrs '}'	{ LL (unLoc $2) }
	|     vocurly    gadt_constrs close	{ $2 }

gadt_constrs :: { Located [LConDecl RdrName] }
        : gadt_constrs ';' gadt_constr  { LL ($3 : unLoc $1) }
742
        | gadt_constrs ';' 		{ $1 }
743 744
        | gadt_constr                   { L1 [$1] } 

745 746 747 748 749 750
-- 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

751
gadt_constr :: { LConDecl RdrName }
752
        : con '::' sigtype
753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768
              { LL (mkGadtDecl $1 $3) } 
        -- Syntax: Maybe merge the record stuff with the single-case above?
        --         (to kill the mostly harmless reduce/reduce error)
        -- XXX revisit autrijus
	| constr_stuff_record '::' sigtype
		{ let (con,details) = unLoc $1 in 
		  LL (ConDecl con Implicit [] (noLoc []) details (ResTyGADT $3)) }
{-
	| forall context '=>' constr_stuff_record '::' sigtype
		{ let (con,details) = unLoc $4 in 
		  LL (ConDecl con Implicit (unLoc $1) $2 details (ResTyGADT $6)) }
	| forall constr_stuff_record '::' sigtype
		{ let (con,details) = unLoc $2 in 
		  LL (ConDecl con Implicit (unLoc $1) (noLoc []) details (ResTyGADT $4)) }
-}

769 770 771 772 773 774 775 776 777 778 779 780

constrs :: { Located [LConDecl RdrName] }
        : {- empty; a GHC extension -}  { noLoc [] }
        | '=' constrs1                  { LL (unLoc $2) }

constrs1 :: { Located [LConDecl RdrName] }
	: constrs1 '|' constr		{ LL ($3 : unLoc $1) }
	| constr			{ L1 [$1] }

constr :: { LConDecl RdrName }
	: forall context '=>' constr_stuff	
		{ let (con,details) = unLoc $4 in 
781
		  LL (ConDecl con Explicit (unLoc $1) $2 details ResTyH98) }
782 783
	| forall constr_stuff
		{ let (con,details) = unLoc $2 in 
784
		  LL (ConDecl con Explicit (unLoc $1) (noLoc []) details ResTyH98) }
785 786 787 788 789 790

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

constr_stuff :: { Located (Located RdrName, HsConDetails RdrName (LBangType RdrName)) }
791 792 793 794 795 796 797
-- 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)
798 799 800
	: btype				{% mkPrefixCon $1 [] >>= return.LL }
	| oqtycon '{' '}' 		{% mkRecCon $1 [] >>= return.LL }
	| oqtycon '{' fielddecls '}' 	{% mkRecCon $1 $3 >>= return.LL }
801
	| btype conop btype		{ LL ($2, InfixCon $1 $3) }
802

803 804 805 806
constr_stuff_record :: { Located (Located RdrName, HsConDetails RdrName (LBangType RdrName)) }
	: oqtycon '{' '}' 		{% mkRecCon $1 [] >>= return.sL (comb2 $1 $>) }
	| oqtycon '{' fielddecls '}' 	{% mkRecCon $1 $3 >>= return.sL (comb2 $1 $>) }

807 808 809 810 811
fielddecls :: { [([Located RdrName], LBangType RdrName)] }
	: fielddecl ',' fielddecls	{ unLoc $1 : $3 }
	| fielddecl			{ [unLoc $1] }

fielddecl :: { Located ([Located RdrName], LBangType RdrName) }
812
	: sig_vars '::' ctype		{ LL (reverse (unLoc $1), $3) }
813

814 815 816 817
-- 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.
818 819
deriving :: { Located (Maybe [LHsType RdrName]) }
	: {- empty -}				{ noLoc Nothing }
820 821 822
	| 'deriving' qtycon	{% do { let { L loc tv = $2 }
				      ; p <- checkInstType (L loc (HsTyVar tv))
				      ; return (LL (Just [p])) } }
823 824
	| 'deriving' '(' ')'	 		{ LL (Just []) }
	| 'deriving' '(' inst_types1 ')' 	{ LL (Just $3) }
825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850
             -- Glasgow extension: allow partial 
             -- applications in derivings

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

{- There's an awkward overlap with a type signature.  Consider
	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.
-}

851
decl 	:: { Located (OrdList (LHsDecl RdrName)) }
852
	: sigdecl			{ $1 }
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
853 854 855 856
	| '!' infixexp rhs		{% do { pat <- checkPattern $2;
					        return (LL $ unitOL $ LL $ ValD $ 
							PatBind (LL $ BangPat pat) (unLoc $3)
								placeHolderType placeHolderNames) } }
857
	| infixexp opt_sig rhs		{% do { r <- checkValDef $1 $2 $3;
858
						return (LL $ unitOL (LL $ ValD r)) } }
859 860

rhs	:: { Located (GRHSs RdrName) }
861 862
	: '=' exp wherebinds	{ L (comb3 $1 $2 $3) $ GRHSs (unguardedRHS $2) (unLoc $3) }
	| gdrhs	wherebinds	{ LL $ GRHSs (reverse (unLoc $1)) (unLoc $2) }
863 864 865 866 867 868

gdrhs :: { Located [LGRHS RdrName] }
	: gdrhs gdrh		{ LL ($2 : unLoc $1) }
	| gdrh			{ L1 [$1] }

gdrh :: { LGRHS RdrName }
869
	: '|' quals '=' exp  	{ sL (comb2 $1 $>) $ GRHS (reverse (unLoc $2)) $4 }
870

871
sigdecl :: { Located (OrdList (LHsDecl RdrName)) }
872 873
	: infixexp '::' sigtype
				{% do s <- checkValSig $1 $3; 
874
				      return (LL $ unitOL (LL $ SigD s)) }
875 876
		-- See the above notes for why we need infixexp here
	| var ',' sig_vars '::' sigtype	
877
				{ LL $ toOL [ LL $ SigD (TypeSig n $5) | n <- $1 : unLoc $3 ] }
878
	| infix prec ops	{ LL $ toOL [ LL $ SigD (FixSig (FixitySig n (Fixity $2 (unLoc $1))))
879 880
					     | n <- unLoc $3 ] }
	| '{-# INLINE'   activation qvar '#-}'	      
881
				{ LL $ unitOL (LL $ SigD (InlineSig $3 (mkInlineSpec $2 (getINLINE $1)))) }
882
	| '{-# SPECIALISE' qvar '::' sigtypes1 '#-}'
883
			 	{ LL $ toOL [ LL $ SigD (SpecSig $2 t defaultInlineSpec)
884
					    | t <- $4] }
885
	| '{-# SPECIALISE_INLINE' activation qvar '::' sigtypes1 '#-}'
886
			 	{ LL $ toOL [ LL $ SigD (SpecSig $3 t (mkInlineSpec $2 (getSPEC_INLINE $1)))
887
					    | t <- $5] }
888
	| '{-# SPECIALISE' 'instance' inst_type '#-}'
889
				{ LL $ unitOL (LL $ SigD (SpecInstSig $3)) }
890 891 892 893 894 895

-----------------------------------------------------------------------------
-- Expressions

exp   :: { LHsExpr RdrName }
	: infixexp '::' sigtype		{ LL $ ExprWithTySig $1 $3 }
ross's avatar
ross committed
896 897 898 899
	| infixexp '-<' exp		{ LL $ HsArrApp $1 $3 placeHolderType HsFirstOrderApp True }
	| infixexp '>-' exp		{ LL $ HsArrApp $3 $1 placeHolderType HsFirstOrderApp False }
	| infixexp '-<<' exp		{ LL $ HsArrApp $1 $3 placeHolderType HsHigherOrderApp True }
	| infixexp '>>-' exp		{ LL $ HsArrApp $3 $1 placeHolderType HsHigherOrderApp False}
900 901 902 903 904 905 906 907 908
	| infixexp			{ $1 }

infixexp :: { LHsExpr RdrName }
	: exp10				{ $1 }
	| infixexp qop exp10		{ LL (OpApp $1 $2 (panic "fixity") $3) }

exp10 :: { LHsExpr RdrName }
	: '\\' aexp aexps opt_asig '->' exp	
			{% checkPatterns ($2 : reverse $3) >>= \ ps -> 
909
			   return (LL $ HsLam (mkMatchGroup [LL $ Match ps $4
910
					    (GRHSs (unguardedRHS $6) emptyLocalBinds
911
							)])) }
912 913
  	| 'let' binds 'in' exp			{ LL $ HsLet (unLoc $2) $4 }
	| 'if' exp 'then' exp 'else' exp	{ LL $ HsIf $2 $4 $6 }
914
   	| 'case' exp 'of' altslist		{ LL $ HsCase $2 (mkMatchGroup (unLoc $4)) }
915 916 917
	| '-' fexp				{ LL $ mkHsNegApp $2 }

  	| 'do' stmtlist			{% let loc = comb2 $1 $2 in
918 919
					   checkDo loc (unLoc $2)  >>= \ (stmts,body) ->
					   return (L loc (mkHsDo DoExpr stmts body)) }
920
  	| 'mdo' stmtlist		{% let loc = comb2 $1 $2 in
921 922
					   checkDo loc (unLoc $2)  >>= \ (stmts,body) ->
					   return (L loc (mkHsDo (MDoExpr noPostTcTable) stmts body)) }
923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951
        | scc_annot exp		    		{ LL $ if opt_SccProfilingOn
							then HsSCC (unLoc $1) $2
							else HsPar $2 }

	| 'proc' aexp '->' exp	
			{% checkPattern $2 >>= \ p -> 
			   return (LL $ HsProc p (LL $ HsCmdTop $4 [] 
						   placeHolderType undefined)) }
						-- TODO: is LL right here?

        | '{-# CORE' STRING '#-}' exp           { LL $ HsCoreAnn (getSTRING $2) $4 }
						    -- hdaume: core annotation
	| fexp					{ $1 }

scc_annot :: { Located FastString }
	: '_scc_' STRING			{ LL $ getSTRING $2 }
	| '{-# SCC' STRING '#-}'		{ LL $ getSTRING $2 }

fexp 	:: { LHsExpr RdrName }
	: fexp aexp				{ LL $ HsApp $1 $2 }
  	| aexp					{ $1 }

aexps 	:: { [LHsExpr RdrName] }
	: aexps aexp				{ $2 : $1 }
  	| {- empty -}				{ [] }

aexp	:: { LHsExpr RdrName }
	: qvar '@' aexp			{ LL $ EAsPat $1 $3 }
	| '~' aexp			{ LL $ ELazyPat $2 }
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
952
--	| '!' aexp			{ LL $ EBangPat $2 }
953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975
	| aexp1				{ $1 }

aexp1	:: { LHsExpr RdrName }
        : aexp1 '{' fbinds '}' 	{% do { r <- mkRecConstrOrUpdate $1 (comb2 $2 $4) 
							(reverse $3);
				        return (LL r) }}
  	| aexp2			{ $1 }

-- Here was the syntax for type applications that I was planning
-- but there are difficulties (e.g. what order for type args)
-- so it's not enabled yet.
-- But this case *is* used for the left hand side of a generic definition,
-- which is parsed as an expression before being munged into a pattern
 	| qcname '{|' gentype '|}'      { LL $ HsApp (sL (getLoc $1) (HsVar (unLoc $1)))
						     (sL (getLoc $3) (HsType $3)) }

aexp2	:: { LHsExpr RdrName }
	: ipvar				{ L1 (HsIPVar $! unLoc $1) }
	| qcname			{ L1 (HsVar   $! unLoc $1) }
	| literal			{ L1 (HsLit   $! unLoc $1) }
	| INTEGER			{ L1 (HsOverLit $! mkHsIntegral (getINTEGER $1)) }
	| RATIONAL			{ L1 (HsOverLit $! mkHsFractional (getRATIONAL $1)) }
	| '(' exp ')'			{ LL (HsPar $2) }
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
976
	| '(' texp ',' texps ')'	{ LL $ ExplicitTuple ($2 : reverse $4) Boxed }
977 978 979 980 981 982 983
	| '(#' texps '#)'		{ LL $ ExplicitTuple (reverse $2)      Unboxed }
	| '[' list ']'                  { LL (unLoc $2) }
	| '[:' parr ':]'                { LL (unLoc $2) }
	| '(' infixexp qop ')'		{ LL $ SectionL $2 $3 }
	| '(' qopm infixexp ')'		{ LL $ SectionR $2 $3 }
	| '_'				{ L1 EWildPat }
	
984
	-- Template Haskell Extension
985
	| TH_ID_SPLICE          { L1 $ HsSpliceE (mkHsSplice 
986
					(L1 $ HsVar (mkUnqual varName 
987 988 989
							(getTH_ID_SPLICE $1)))) } -- $x
	| '$(' exp ')'   	{ LL $ HsSpliceE (mkHsSplice $2) }               -- $( exp )

990
	| TH_VAR_QUOTE qvar 	{ LL $ HsBracket (VarBr (unLoc $2)) }
991
	| TH_VAR_QUOTE qcon 	{ LL $ HsBracket (VarBr (unLoc $2)) }
992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010
	| TH_TY_QUOTE tyvar 	{ LL $ HsBracket (VarBr (unLoc $2)) }
 	| TH_TY_QUOTE gtycon	{ LL $ HsBracket (VarBr (unLoc $2)) }
	| '[|' exp '|]'         { LL $ HsBracket (ExpBr $2) }                       
	| '[t|' ctype '|]'      { LL $ HsBracket (TypBr $2) }                       
	| '[p|' infixexp '|]'   {% checkPattern $2 >>= \p ->
					   return (LL $ HsBracket (PatBr p)) }
	| '[d|' cvtopbody '|]'	{ LL $ HsBracket (DecBr (mkGroup $2)) }

	-- arrow notation extension
	| '(|' aexp2 cmdargs '|)'	{ LL $ HsArrForm $2 Nothing (reverse $3) }

cmdargs	:: { [LHsCmdTop RdrName] }
	: cmdargs acmd			{ $2 : $1 }
  	| {- empty -}			{ [] }

acmd	:: { LHsCmdTop RdrName }
	: aexp2			{ L1 $ HsCmdTop $1 [] placeHolderType undefined }

cvtopbody :: { [LHsDecl RdrName] }
1011 1012 1013 1014 1015 1016
	:  '{'            cvtopdecls0 '}'		{ $2 }
	|      vocurly    cvtopdecls0 close		{ $2 }

cvtopdecls0 :: { [LHsDecl RdrName] }
	: {- empty -}		{ [] }
	| cvtopdecls		{ $1 }
1017

simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
1018 1019 1020 1021 1022 1023
texp :: { LHsExpr RdrName }
	: exp				{ $1 }
	| qopm infixexp			{ LL $ SectionR $1 $2 }
	-- The second production is really here only for bang patterns
	-- but 

1024
texps :: { [LHsExpr RdrName] }
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
1025 1026
	: texps ',' texp		{ $3 : $1 }
	| texp				{ [$1] }
1027 1028 1029 1030 1031 1032 1033 1034 1035


-----------------------------------------------------------------------------
-- List expressions

-- The rules below are little bit contorted to keep lexps left-recursive while
-- avoiding another shift/reduce-conflict.

list :: { LHsExpr RdrName }
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
1036
	: texp			{ L1 $ ExplicitList placeHolderType [$1] }
1037
	| lexps 		{ L1 $ ExplicitList placeHolderType (reverse (unLoc $1)) }
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
1038 1039 1040 1041 1042
	| texp '..'		{ LL $ ArithSeq noPostTcExpr (From $1) }
	| texp ',' exp '..' 	{ LL $ ArithSeq noPostTcExpr (FromThen $1 $3) }
	| texp '..' exp	 	{ LL $ ArithSeq noPostTcExpr (FromTo $1 $3) }
	| texp ',' exp '..' exp	{ LL $ ArithSeq noPostTcExpr (FromThenTo $1 $3 $5) }
	| texp pquals		{ sL (comb2 $1 $>) $ mkHsDo ListComp (reverse (unLoc $2)) $1 }
1043 1044

lexps :: { Located [LHsExpr RdrName] }
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
1045 1046
	: lexps ',' texp 		{ LL ($3 : unLoc $1) }
	| texp ',' texp			{ LL [$3,$1] }
1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081

-----------------------------------------------------------------------------
-- List Comprehensions

pquals :: { Located [LStmt RdrName] }	-- Either a singleton ParStmt, 
					-- or a reversed list of Stmts
	: pquals1			{ case unLoc $1 of
					    [qs] -> L1 qs
					    qss  -> L1 [L1 (ParStmt stmtss)]
						 where
						    stmtss = [ (reverse qs, undefined) 
						    	     | qs <- qss ]
					}
			
pquals1 :: { Located [[LStmt RdrName]] }
	: pquals1 '|' quals		{ LL (unLoc $3 : unLoc $1) }
	| '|' quals			{ L (getLoc $2) [unLoc $2] }

quals :: { Located [LStmt RdrName] }
	: quals ',' qual		{ LL ($3 : unLoc $1) }
	| qual				{ L1 [$1] }

-----------------------------------------------------------------------------
-- Parallel array expressions

-- The rules below are little bit contorted; see the list case for details.
-- Note that, in contrast to lists, we only have finite arithmetic sequences.
-- Moreover, we allow explicit arrays with no element (represented by the nil
-- constructor in the list case).

parr :: { LHsExpr RdrName }
	: 				{ noLoc (ExplicitPArr placeHolderType []) }
	| exp				{ L1 $ ExplicitPArr placeHolderType [$1] }
	| lexps 			{ L1 $ ExplicitPArr placeHolderType 
						       (reverse (unLoc $1)) }
1082 1083 1084
	| exp '..' exp	 		{ LL $ PArrSeq noPostTcExpr (FromTo $1 $3) }
	| exp ',' exp '..' exp		{ LL $ PArrSeq noPostTcExpr (FromThenTo $1 $3 $5) }
	| exp pquals			{ sL (comb2 $1 $>) $ mkHsDo PArrComp (reverse (unLoc $2)) $1 }
1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108

-- We are reusing `lexps' and `pquals' from the list case.

-----------------------------------------------------------------------------
-- Case alternatives

altslist :: { Located [LMatch RdrName] }
	: '{'            alts '}'	{ LL (reverse (unLoc $2)) }
	|     vocurly    alts  close	{ L (getLoc $2) (reverse (unLoc $2)) }

alts    :: { Located [LMatch RdrName] }
        : alts1				{ L1 (unLoc $1) }
	| ';' alts			{ LL (unLoc $2) }

alts1 	:: { Located [LMatch RdrName] }
	: alts1 ';' alt			{ LL ($3 : unLoc $1) }
	| alts1 ';'			{ LL (unLoc $1) }
	| alt				{ L1 [$1] }

alt 	:: { LMatch RdrName }
	: infixexp opt_sig alt_rhs	{%  checkPattern $1 >>= \p ->
			    		    return (LL (Match [p] $2 (unLoc $3))) }

alt_rhs :: { Located (GRHSs RdrName) }
1109
	: ralt wherebinds		{ LL (GRHSs (unLoc $1) (unLoc $2)) }
1110 1111 1112 1113 1114 1115 1116 1117 1118 1119

ralt :: { Located [LGRHS RdrName] }
	: '->' exp			{ LL (unguardedRHS $2) }
	| gdpats			{ L1 (reverse (unLoc $1)) }

gdpats :: { Located [LGRHS RdrName] }
	: gdpats gdpat			{ LL ($2 : unLoc $1) }
	| gdpat				{ L1 [$1] }

gdpat	:: { LGRHS RdrName }
1120
	: '|' quals '->' exp	 	{ sL (comb2 $1 $>) $ GRHS (reverse (unLoc $2)) $4 }
1121 1122 1123 1124 1125 1126 1127 1128 1129

-----------------------------------------------------------------------------
-- Statement sequences

stmtlist :: { Located [LStmt RdrName] }
	: '{'         	stmts '}'	{ LL (unLoc $2) }
	|     vocurly   stmts close	{ $2 }

--	do { ;; s ; s ; ; s ;; }
1130
-- The last Stmt should be an expression, but that's hard to enforce
1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
-- here, because we need too much lookahead if we see do { e ; }
-- So we use ExprStmts throughout, and switch the last one over
-- in ParseUtils.checkDo instead
stmts :: { Located [LStmt RdrName] }
	: stmt stmts_help		{ LL ($1 : unLoc $2) }
	| ';' stmts			{ LL (unLoc $2) }
	| {- empty -}			{ noLoc [] }

stmts_help :: { Located [LStmt RdrName] } -- might be empty
	: ';' stmts			{ LL (unLoc $2) }
	| {- empty -}			{ noLoc [] }

-- For typing stmts at the GHCi prompt, where 
-- the input may consist of just comments.
maybe_stmt :: { Maybe (LStmt RdrName) }
	: stmt				{ Just $1 }
	| {- nothing -}			{ Nothing }

stmt  :: { LStmt RdrName }
	: qual				{ $1 }
	| infixexp '->' exp		{% checkPattern $3 >>= \p ->
1152 1153
					   return (LL $ mkBindStmt p $1) }
  	| 'rec' stmtlist		{ LL $ mkRecStmt (unLoc $2) }
1154 1155

qual  :: { LStmt RdrName }
1156
	: exp '<-' exp			{% checkPattern $1 >>= \p ->
1157 1158
					   return (LL $ mkBindStmt p $3) }
	| exp				{ L1 $ mkExprStmt $1 }
1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186
  	| 'let' binds			{ LL $ LetStmt (unLoc $2) }

-----------------------------------------------------------------------------
-- Record Field Update/Construction

fbinds 	:: { HsRecordBinds RdrName }
	: fbinds1			{ $1 }
  	| {- empty -}			{ [] }

fbinds1	:: { HsRecordBinds RdrName }
	: fbinds1 ',' fbind		{ $3 : $1 }
	| fbind				{ [$1] }
  
fbind	:: { (Located RdrName, LHsExpr RdrName) }
	: qvar '=' exp			{ ($1,$3) }

-----------------------------------------------------------------------------
-- Implicit Parameter Bindings

dbinds 	:: { Located [LIPBind RdrName] }
	: dbinds ';' dbind		{ LL ($3 : unLoc $1) }
	| dbinds ';'			{ LL (unLoc $1) }
	| dbind				{ L1 [$1] }
--	| {- empty -}			{ [] }

dbind	:: { LIPBind RdrName }
dbind	: ipvar '=' exp			{ LL (IPBind (unLoc $1) $3) }

1187 1188 1189
ipvar	:: { Located (IPName RdrName) }
	: IPDUPVARID		{ L1 (Dupable (mkUnqual varName (getIPDUPVARID $1))) }
	| IPSPLITVARID		{ L1 (Linear  (mkUnqual varName (getIPSPLITVARID $1))) }
1190

1191 1192
-----------------------------------------------------------------------------
-- Deprecations
1193 1194 1195 1196 1197 1198 1199

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

deprec_var :: { Located RdrName }
deprec_var : var			{ $1 }
1200
	   | con			{ $1 }
1201

1202 1203
-----------------------------------------
-- Data constructors
1204 1205 1206
qcon	:: { Located RdrName }
	: qconid		{ $1 }
	| '(' qconsym ')'	{ LL (unLoc $2) }
1207 1208
	| sysdcon		{ L1 $ nameRdrName (dataConName (unLoc $1)) }
-- The case of '[:' ':]' is part of the production `parr'
1209

1210 1211 1212 1213
con	:: { Located RdrName }
	: conid			{ $1 }
	| '(' consym ')'	{ LL (unLoc $2) }
	| sysdcon		{ L1 $ nameRdrName (dataConName (unLoc $1)) }
1214

1215 1216 1217 1218
sysdcon	:: { Located DataCon }	-- Wired in data constructors
	: '(' ')'		{ LL unitDataCon }
	| '(' commas ')'	{ LL $ tupleCon Boxed $2 }
	| '[' ']'		{ LL nilDataCon }
1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261

conop :: { Located RdrName }
	: consym		{ $1 }	
	| '`' conid '`'		{ LL (unLoc $2) }

qconop :: { Located RdrName }
	: qconsym		{ $1 }
	| '`' qconid '`'	{ LL (unLoc $2) }

-----------------------------------------------------------------------------
-- Type constructors

gtycon 	:: { Located RdrName }	-- A "general" qualified tycon
	: oqtycon			{ $1 }
	| '(' ')'			{ LL $ getRdrName unitTyCon }
	| '(' commas ')'		{ LL $ getRdrName (tupleTyCon Boxed $2) }
	| '(' '->' ')'			{ LL $ getRdrName funTyCon }
	| '[' ']'			{ LL $ listTyCon_RDR }
	| '[:' ':]'			{ LL $ parrTyCon_RDR }

oqtycon :: { Located RdrName }	-- An "ordinary" qualified tycon
	: qtycon			{ $1 }
 	| '(' qtyconsym ')'		{ LL (unLoc $2) }

qtyconop :: { Located RdrName }	-- Qualified or unqualified
	: qtyconsym			{ $1 }
	| '`' qtycon '`'		{ LL (unLoc $2) }

qtycon :: { Located RdrName }	-- Qualified or unqualified
	: QCONID			{ L1 $! mkQual tcClsName (getQCONID $1) }
	| tycon				{ $1 }

tycon 	:: { Located RdrName }	-- Unqualified
	: CONID				{ L1 $! mkUnqual tcClsName (getCONID $1) }

qtyconsym :: { Located RdrName }
	: QCONSYM			{ L1 $! mkQual tcClsName (getQCONSYM $1) }
	| tyconsym			{ $1 }

tyconsym :: { Located RdrName }
	: CONSYM			{ L1 $! mkUnqual tcClsName (getCONSYM $1) }

-----------------------------------------------------------------------------
1262
-- Operators
1263 1264 1265 1266 1267

op	:: { Located RdrName }   -- used in infix decls
	: varop			{ $1 }
	| conop 		{ $1 }

1268 1269 1270 1271
varop	:: { Located RdrName }
	: varsym		{ $1 }
	| '`' varid '`'		{ LL (unLoc $2) }

1272 1273 1274 1275 1276 1277 1278 1279
qop	:: { LHsExpr RdrName }   -- used in sections
	: qvarop		{ L1 $ HsVar (unLoc $1) }
	| qconop		{ L1 $ HsVar (unLoc $1) }

qopm	:: { LHsExpr RdrName }   -- used in sections
	: qvaropm		{ L1 $ HsVar (unLoc $1) }
	| qconop		{ L1 $ HsVar (unLoc $1) }

1280 1281 1282
qvarop :: { Located RdrName }
	: qvarsym		{ $1 }
	| '`' qvarid '`'	{ LL (unLoc $2) }
1283

1284 1285 1286
qvaropm :: { Located RdrName }
	: qvarsym_no_minus	{ $1 }
	| '`' qvarid '`'	{ LL (unLoc $2) }
1287

1288 1289
-----------------------------------------------------------------------------
-- Type variables
1290

1291 1292 1293 1294 1295 1296 1297 1298 1299
tyvar   :: { Located RdrName }
tyvar   : tyvarid		{ $1 }
	| '(' tyvarsym ')'	{ LL (unLoc $2) }

tyvarop :: { Located RdrName }
tyvarop : '`' tyvarid '`'	{ LL (unLoc $2) }
	| tyvarsym		{ $1 }

tyvarid	:: { Located RdrName }
1300 1301 1302 1303 1304 1305
	: VARID			{ L1 $! mkUnqual tvName (getVARID $1) }
	| special_id		{ L1 $! mkUnqual tvName (unLoc $1) }
	| 'unsafe' 		{ L1 $! mkUnqual tvName FSLIT("unsafe") }
	| 'safe' 		{ L1 $! mkUnqual tvName FSLIT("safe") }
	| 'threadsafe' 		{ L1 $! mkUnqual tvName FSLIT("threadsafe") }

1306 1307 1308 1309 1310 1311
tyvarsym :: { Located RdrName }
-- Does not include "!", because that is used for strictness marks
--	         or ".", because that separates the quantified type vars from the rest
--		 or "*", because that's used for kinds
tyvarsym : VARSYM		{ L1 $! mkUnqual tvName (getVARSYM $1) }

1312 1313 1314
-----------------------------------------------------------------------------
-- Variables 

1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341
var 	:: { Located RdrName }
	: varid			{ $1 }
	| '(' varsym ')'	{ LL (unLoc $2) }

qvar 	:: { Located RdrName }
	: qvarid		{ $1 }
	| '(' varsym ')'	{ LL (unLoc $2) }
	| '(' qvarsym1 ')'	{ LL (unLoc $2) }
-- We've inlined qvarsym here so that the decision about
-- whether it's a qvar or a var can be postponed until
-- *after* we see the close paren.

qvarid :: { Located RdrName }
	: varid			{ $1 }
	| QVARID		{ L1 $ mkQual varName (getQVARID $1) }

varid :: { Located RdrName }
	: varid_no_unsafe 	{ $1 }
	| 'unsafe'		{ L1 $! mkUnqual varName FSLIT("unsafe") }
	| 'safe'		{ L1 $! mkUnqual varName FSLIT("safe") }
	| 'threadsafe'		{ L1 $! mkUnqual varName FSLIT("threadsafe") }

varid_no_unsafe :: { Located RdrName }
	: VARID			{ L1 $! mkUnqual varName (getVARID $1) }
	| special_id		{ L1 $! mkUnqual varName (unLoc $1) }
	| 'forall'		{ L1 $! mkUnqual varName FSLIT("forall") }

1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356