Parser.y.pp 72 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
{-# OPTIONS -w #-}
12 13 14
-- 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
Ian Lynagh's avatar
Ian Lynagh committed
15
--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
16 17
-- for details

18
module Parser ( parseModule, parseStmt, parseIdentifier, parseType,
19
		parseHeader ) where
20 21 22

import HsSyn
import RdrHsSyn
23
import HscTypes		( IsBootInterface, DeprecTxt )
24 25 26
import Lexer
import RdrName
import TysWiredIn	( unitTyCon, unitDataCon, tupleTyCon, tupleCon, nilDataCon,
27
			  unboxedSingletonTyCon, unboxedSingletonDataCon,
28 29
			  listTyCon_RDR, parrTyCon_RDR, consDataCon_RDR )
import Type		( funTyCon )
30
import ForeignCall	( Safety(..), CExportSpec(..), CLabelString,
31 32
			  CCallConv(..), CCallTarget(..), defaultCCallConv
			)
33
import OccName		( varName, dataName, tcClsName, tvName )
34 35
import DataCon		( DataCon, dataConName )
import SrcLoc		( Located(..), unLoc, getLoc, noLoc, combineSrcSpans,
36 37
			  SrcSpan, combineLocs, srcLocFile, 
			  mkSrcLoc, mkSrcSpan )
38
import Module
andy@galois.com's avatar
andy@galois.com committed
39
import StaticFlags	( opt_SccProfilingOn, opt_Hpc )
Simon Marlow's avatar
Simon Marlow committed
40
import Type		( Kind, mkArrowKind, liftedTypeKind, unliftedTypeKind )
41
import BasicTypes	( Boxity(..), Fixity(..), FixityDirection(..), IPName(..),
42
			  Activation(..), defaultInlineSpec )
43
import DynFlags
44
import OrdList
45 46 47
import HaddockParse
import {-# SOURCE #-} HaddockLex hiding ( Token )
import HaddockUtils
48 49 50 51

import FastString
import Maybes		( orElse )
import Outputable
52

53
import Control.Monad    ( unless )
Simon Marlow's avatar
Simon Marlow committed
54
import GHC.Exts
55 56
import Data.Char
import Control.Monad    ( mplus )
57 58 59
}

{-
60 61 62 63 64 65 66 67 68 69 70
-----------------------------------------------------------------------------
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

71 72 73 74 75 76 77 78 79 80 81
-----------------------------------------------------------------------------
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

82 83 84 85 86 87 88 89 90 91 92
-----------------------------------------------------------------------------
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

93 94 95 96 97 98 99 100 101 102 103
-----------------------------------------------------------------------------
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

104
-----------------------------------------------------------------------------
105
Conflicts: 38 shift/reduce (1.25)
106

107
10 for abiguity in 'if x then y else z + 1'		[State 178]
108 109 110
	(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

111
1 for ambiguity in 'if x then y else z :: T'		[State 178]
112 113
	(shift parses as 'if x then y else (z :: T)', as per longest-parse rule)

114
4 for ambiguity in 'if x then y else z -< e'		[State 178]
115
	(shift parses as 'if x then y else (z -< T)', as per longest-parse rule)
116 117 118 119 120 121 122 123 124 125
	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 ...
126

127
10 for ambiguity in 'e :: a `b` c'.  Does this mean 	[States 11, 253]
128 129
	(e::a) `b` c, or 
	(e :: (a `b` c))
130
    As well as `b` we can have !, VARSYM, QCONSYM, and CONSYM, hence 5 cases
131
    Same duplication between states 11 and 253 as the previous case
132

133
1 for ambiguity in 'let ?x ...'				[State 329]
134 135 136 137
	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.

138
1 for ambiguity in '{-# RULES "name" [ ... #-}		[State 382]
139 140 141 142
	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

143
1 for ambiguity in '{-# RULES "name" forall = ... #-}' 	[State 474]
144 145 146 147 148 149 150
	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'.

151 152 153 154
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.   

155 156 157 158 159 160 161 162 163 164 165
-- ---------------------------------------------------------------------------
-- 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
166
     -- This doesn't seem to work anymore -=chak
167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228

   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

229
 'forall'	{ L _ ITforall }		-- GHC extension keywords
230 231 232 233 234 235 236 237
 'foreign'	{ L _ ITforeign }
 'export'	{ L _ ITexport }
 'label'	{ L _ ITlabel } 
 'dynamic'	{ L _ ITdynamic }
 'safe'		{ L _ ITsafe }
 'threadsafe'	{ L _ ITthreadsafe }
 'unsafe'	{ L _ ITunsafe }
 'mdo'		{ L _ ITmdo }
238
 'family'	{ L _ ITfamily }
239 240 241 242 243
 'stdcall'      { L _ ITstdcallconv }
 'ccall'        { L _ ITccallconv }
 'dotnet'       { L _ ITdotnet }
 'proc'		{ L _ ITproc }		-- for arrow notation extension
 'rec'		{ L _ ITrec }		-- for arrow notation extension
244 245 246
 'group'    { L _ ITgroup }     -- for list transform extension
 'by'       { L _ ITby }        -- for list transform extension
 'using'    { L _ ITusing }     -- for list transform extension
247

248 249 250
 '{-# INLINE'      	  { L _ (ITinline_prag _) }
 '{-# SPECIALISE'  	  { L _ ITspec_prag }
 '{-# SPECIALISE_INLINE'  { L _ (ITspec_inline_prag _) }
251 252 253 254
 '{-# 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
255
 '{-# GENERATED'   { L _ ITgenerated_prag }
256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318
 '{-# 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

 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
319
 PRIMWORD 	{ L _ (ITprimword  _) }
320 321
 PRIMFLOAT	{ L _ (ITprimfloat  _) }
 PRIMDOUBLE	{ L _ (ITprimdouble _) }
322 323 324 325 326 327

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

328 329 330 331 332 333 334 335 336 337
-- 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
338
TH_QUASIQUOTE	{ L _ (ITquasiQuote _) }
339 340 341 342 343 344

%monad { P } { >>= } { return }
%lexer { lexer } { L _ ITeof }
%name parseModule module
%name parseStmt   maybe_stmt
%name parseIdentifier  identifier
345
%name parseType ctype
346
%partial parseHeader header
347
%tokentype { (Located Token) }
348 349
%%

350 351 352 353 354 355 356
-----------------------------------------------------------------------------
-- Identifiers; one of the entry points
identifier :: { Located RdrName }
	: qvar				{ $1 }
	| qcon				{ $1 }
	| qvarop			{ $1 }
	| qconop			{ $1 }
357
    | '(' '->' ')'      { LL $ getRdrName funTyCon }
358

359 360 361 362 363 364 365 366 367 368 369
-----------------------------------------------------------------------------
-- 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) }
David Waern's avatar
David Waern committed
370 371 372 373
 	: maybedocheader 'module' modid maybemoddeprec maybeexports 'where' body
		{% fileSrcSpan >>= \ loc -> case $1 of { (info, doc) ->
		   return (L loc (HsModule (Just $3) $5 (fst $7) (snd $7) $4
                          info doc) )}}
374
        | body2
375
		{% fileSrcSpan >>= \ loc ->
David Waern's avatar
David Waern committed
376 377
		   return (L loc (HsModule Nothing Nothing
                          (fst $1) (snd $1) Nothing emptyHaddockModInfo
378 379
                          Nothing)) }

David Waern's avatar
David Waern committed
380 381 382
maybedocheader :: { (HaddockModInfo RdrName, Maybe (HsDoc RdrName)) }
        : moduleheader            { (fst $1, snd $1) }
        | {- empty -}             { (emptyHaddockModInfo, Nothing) }
383 384 385 386 387 388 389 390 391 392 393 394

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 }

395 396 397 398
body2 	:: { ([LImportDecl RdrName], [LHsDecl RdrName]) }
	:  '{' top '}'          		{ $2 }
 	|  missing_module_keyword top close     { $2 }

399 400 401 402 403 404 405 406
top 	:: { ([LImportDecl RdrName], [LHsDecl RdrName]) }
	: importdecls				{ (reverse $1,[]) }
	| importdecls ';' cvtopdecls		{ (reverse $1,$3) }
	| cvtopdecls				{ ([],$1) }

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

407 408 409 410
-----------------------------------------------------------------------------
-- Module declaration & imports only

header 	:: { Located (HsModule RdrName) }
David Waern's avatar
David Waern committed
411 412 413 414
 	: maybedocheader 'module' modid maybemoddeprec maybeexports 'where' header_body
		{% fileSrcSpan >>= \ loc -> case $1 of { (info, doc) ->
		   return (L loc (HsModule (Just $3) $5 $7 [] $4
                   info doc))}}
415 416
	| missing_module_keyword importdecls
		{% fileSrcSpan >>= \ loc ->
David Waern's avatar
David Waern committed
417 418
		   return (L loc (HsModule Nothing Nothing $2 [] Nothing
                   emptyHaddockModInfo Nothing)) }
419 420 421 422 423

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

424 425 426 427 428 429 430
-----------------------------------------------------------------------------
-- The Export List

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

431 432
exportlist :: { [LIE RdrName] }
	: expdoclist ',' expdoclist		{ $1 ++ $3 }
433 434 435
	| exportlist1				{ $1 }

exportlist1 :: { [LIE RdrName] }
436 437 438 439 440 441 442 443 444 445 446 447 448
        : 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)) }       
                       
449 450 451 452 453 454 455 456 457 458 459
   -- 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] }
460 461
	:  qcnames ',' qcname_ext	{ unLoc $3 : $1 }
	|  qcname_ext			{ [unLoc $1]  }
462

463 464 465 466 467 468 469 470
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.
471
qcname 	:: { Located RdrName }	-- Variable or data constructor
472 473
	:  qvar				{ $1 }
	|  qcon				{ $1 }
474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498

-----------------------------------------------------------------------------
-- 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
499
maybeas :: { Located (Maybe ModuleName) }
500 501 502 503 504 505 506 507
      	: '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]) }
508 509
	:  '(' exportlist ')'  			{ LL (False, $2) }
	|  'hiding' '(' exportlist ')' 		{ LL (True,  $3) }
510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529

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

530
topdecls :: { OrdList (LHsDecl RdrName) }
531 532 533
        : topdecls ';' topdecl		        { $1 `appOL` $3 }
        | topdecls ';'			        { $1 }
	| topdecl			        { $1 }
534

535
topdecl :: { OrdList (LHsDecl RdrName) }
536
  	: cl_decl			{ unitOL (L1 (TyClD (unLoc $1))) }
chak@cse.unsw.edu.au.'s avatar
chak@cse.unsw.edu.au. committed
537
  	| ty_decl			{ unitOL (L1 (TyClD (unLoc $1))) }
538 539 540 541
	| '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)))}
542
        | stand_alone_deriving                  { unitOL (LL (DerivD (unLoc $1))) }
543 544 545 546
	| 'default' '(' comma_types0 ')'	{ unitOL (LL $ DefD (DefaultDecl $3)) }
	| 'foreign' fdecl			{ unitOL (LL (unLoc $2)) }
	| '{-# DEPRECATED' deprecations '#-}'	{ $2 }
	| '{-# RULES' rules '#-}'		{ $2 }
547 548
      	| decl					{ unLoc $1 }

549 550 551 552 553 554
	-- Template Haskell Extension
	| '$(' exp ')'				{ unitOL (LL $ SpliceD (SpliceDecl $2)) }
	| TH_ID_SPLICE				{ unitOL (LL $ SpliceD (SpliceDecl $
							L1 $ HsVar (mkUnqual varName (getTH_ID_SPLICE $1))
						  )) }

555 556 557
-- Type classes
--
cl_decl :: { LTyClDecl RdrName }
558
	: 'class' tycl_hdr fds where_cls
559
		{% do { let { (binds, sigs, ats, docs)           = 
560
			        cvBindsAndSigs (unLoc $4)
561
		            ; (ctxt, tc, tvs, tparms) = unLoc $2}
562
                      ; checkTyVars tparms      -- only type vars allowed
563
		      ; checkKindSigs ats
564 565
		      ; return $ L (comb4 $1 $2 $3 $4) 
				   (mkClassDecl (ctxt, tc, tvs) 
566
					        (unLoc $3) sigs binds ats docs) } }
567

568
-- Type declarations (toplevel)
569 570
--
ty_decl :: { LTyClDecl RdrName }
571 572 573 574 575 576
           -- ordinary type synonyms
        : 'type' type '=' ctype
		-- 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
577 578
	        --
		-- Note the use of type for the head; this allows
579 580 581
		-- infix type constructors to be declared 
 		{% do { (tc, tvs, _) <- checkSynHdr $2 False
		      ; return (L (comb2 $1 $4) 
582
				  (TySynonym tc tvs Nothing $4))
583 584 585
                      } }

           -- type family declarations
586
        | 'type' 'family' type opt_kind_sig 
587 588
		-- Note the use of type for the head; this allows
		-- infix type constructors to be declared
589
		--
590 591
 		{% do { (tc, tvs, _) <- checkSynHdr $3 False
		      ; return (L (comb3 $1 $3 $4) 
592
				  (TyFamily TypeFamily tc tvs (unLoc $4)))
593 594 595 596 597 598 599 600 601 602 603
		      } }

           -- type instance declarations
        | 'type' 'instance' type '=' ctype
		-- Note the use of type for the head; this allows
		-- infix type constructors and type patterns
		--
 		{% do { (tc, tvs, typats) <- checkSynHdr $3 True
		      ; return (L (comb2 $1 $5) 
				  (TySynonym tc tvs (Just typats) $5)) 
                      } }
604

605
          -- ordinary data type or newtype declaration
606
	| data_or_newtype tycl_hdr constrs deriving
607
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $2}
608
                      ; checkTyVars tparms    -- no type pattern
609 610 611 612
		      ; return $
			  L (comb4 $1 $2 $3 $4)
			           -- We need the location on tycl_hdr in case 
				   -- constrs and deriving are both empty
613 614
			    (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) 
			       Nothing (reverse (unLoc $3)) (unLoc $4)) } }
615

616
          -- ordinary GADT declaration
617
        | data_or_newtype tycl_hdr opt_kind_sig 
618
		 'where' gadt_constrlist
619
		 deriving
620
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $2}
621
                      ; checkTyVars tparms    -- can have type pats
622 623
		      ; return $
			  L (comb4 $1 $2 $4 $5)
624 625
			    (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) 
			      (unLoc $3) (reverse (unLoc $5)) (unLoc $6)) } }
626

627
          -- data/newtype family
628
        | 'data' 'family' tycl_hdr opt_kind_sig
629
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $3}
630 631 632 633
                      ; checkTyVars tparms            -- no type pattern
		      ; unless (null (unLoc ctxt)) $  -- and no context
			  parseError (getLoc ctxt) 
			    "A family declaration cannot have a context"
634
		      ; return $
635
			  L (comb3 $1 $2 $4)
636
			    (TyFamily DataFamily tc tvs (unLoc $4)) } }
637

638
          -- data/newtype instance declaration
639 640 641 642 643 644 645 646 647 648
	| data_or_newtype 'instance' tycl_hdr constrs deriving
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $3}
                                             -- can have type pats
		      ; return $
			  L (comb4 $1 $3 $4 $5)
			           -- We need the location on tycl_hdr in case 
				   -- constrs and deriving are both empty
			    (mkTyData (unLoc $1) (ctxt, tc, tvs, Just tparms) 
			      Nothing (reverse (unLoc $4)) (unLoc $5)) } }

649
          -- GADT instance declaration
650 651 652 653 654 655 656 657
        | data_or_newtype 'instance' tycl_hdr opt_kind_sig 
		 'where' gadt_constrlist
		 deriving
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $3}
                                             -- can have type pats
		      ; return $
			  L (comb4 $1 $3 $6 $7)
			    (mkTyData (unLoc $1) (ctxt, tc, tvs, Just tparms) 
658
			       (unLoc $4) (reverse (unLoc $6)) (unLoc $7)) } }
659

660 661 662 663 664 665 666 667
-- Associate type family declarations
--
-- * 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. 
668
--
669
at_decl_cls :: { LTyClDecl RdrName }
670
           -- type family declarations
671
        : 'type' type opt_kind_sig
672 673 674
		-- Note the use of type for the head; this allows
		-- infix type constructors to be declared
		--
675 676
 		{% do { (tc, tvs, _) <- checkSynHdr $2 False
		      ; return (L (comb3 $1 $2 $3) 
677
				  (TyFamily TypeFamily tc tvs (unLoc $3)))
678 679
		      } }

680
           -- default type instance
681
        | 'type' type '=' ctype
682 683 684
		-- Note the use of type for the head; this allows
		-- infix type constructors and type patterns
		--
685 686 687
 		{% do { (tc, tvs, typats) <- checkSynHdr $2 True
		      ; return (L (comb2 $1 $4) 
				  (TySynonym tc tvs (Just typats) $4)) 
688 689
                      } }

690
          -- data/newtype family declaration
691
        | 'data' tycl_hdr opt_kind_sig
692
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $2}
693 694 695 696
                      ; checkTyVars tparms            -- no type pattern
		      ; unless (null (unLoc ctxt)) $  -- and no context
			  parseError (getLoc ctxt) 
			    "A family declaration cannot have a context"
697
		      ; return $
698
			  L (comb3 $1 $2 $3)
699
			    (TyFamily DataFamily tc tvs (unLoc $3)) 
700
                      } }
701 702 703 704 705 706 707 708 709 710 711 712 713

-- Associate type instances
--
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
		--
 		{% do { (tc, tvs, typats) <- checkSynHdr $2 True
		      ; return (L (comb2 $1 $4) 
				  (TySynonym tc tvs (Just typats) $4)) 
                      } }
714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734

        -- data/newtype instance declaration
	| data_or_newtype tycl_hdr constrs deriving
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $2}
                                             -- can have type pats
		      ; return $
			  L (comb4 $1 $2 $3 $4)
			           -- We need the location on tycl_hdr in case 
				   -- constrs and deriving are both empty
			    (mkTyData (unLoc $1) (ctxt, tc, tvs, Just tparms) 
			      Nothing (reverse (unLoc $3)) (unLoc $4)) } }

        -- GADT instance declaration
        | data_or_newtype tycl_hdr opt_kind_sig 
		 'where' gadt_constrlist
		 deriving
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $2}
                                             -- can have type pats
		      ; return $
			  L (comb4 $1 $2 $5 $6)
			    (mkTyData (unLoc $1) (ctxt, tc, tvs, Just tparms) 
735
			     (unLoc $3) (reverse (unLoc $5)) (unLoc $6)) } }
736

737 738 739 740
data_or_newtype :: { Located NewOrData }
	: 'data'	{ L1 DataType }
	| 'newtype'	{ L1 NewType }

741 742 743
opt_kind_sig :: { Located (Maybe Kind) }
	: 				{ noLoc Nothing }
	| '::' kind			{ LL (Just (unLoc $2)) }
744

745
-- tycl_hdr parses the header of a class or data type decl,
746 747 748 749
-- which takes the form
--	T a b
-- 	Eq a => T a
--	(Eq a, Ord b) => T a b
750
--      T Int [a]			-- for associated types
751
-- Rather a lot of inlining here, else we get reduce/reduce errors
752 753 754
tycl_hdr :: { Located (LHsContext RdrName, 
		       Located RdrName, 
		       [LHsTyVarBndr RdrName],
755
		       [LHsType RdrName]) }
756
	: context '=>' type		{% checkTyClHdr $1         $3 >>= return.LL }
757 758
	| type				{% checkTyClHdr (noLoc []) $1 >>= return.L1 }

759 760 761 762 763
-----------------------------------------------------------------------------
-- Stand-alone deriving

-- Glasgow extension: stand-alone deriving declarations
stand_alone_deriving :: { LDerivDecl RdrName }
764
  	: 'deriving' 'instance' inst_type {% checkDerivDecl (LL (DerivDecl $3)) }
765

766 767 768
-----------------------------------------------------------------------------
-- Nested declarations

769
-- Declaration in class bodies
770
--
771 772 773 774 775 776 777 778 779
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 }
780 781


782
decllist_cls
783
        :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
784 785
	: '{'         decls_cls '}'	{ LL (unLoc $2) }
	|     vocurly decls_cls close	{ $2 }
786

787
-- Class body
788
--
789
where_cls :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
790 791
				-- No implicit parameters
				-- May have type declarations
792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817
	: '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) }
818 819
	| {- empty -}			{ noLoc nilOL }

820 821
-- Declarations in binding groups other than classes and instances
--
822
decls 	:: { Located (OrdList (LHsDecl RdrName)) }	
Ian Lynagh's avatar
Ian Lynagh committed
823 824
	: decls ';' decl		{ let { this = unLoc $3;
                                    rest = unLoc $1;
Ian Lynagh's avatar
Ian Lynagh committed
825
                                    these = rest `appOL` this }
Ian Lynagh's avatar
Ian Lynagh committed
826 827
                              in rest `seq` this `seq` these `seq`
                                    LL these }
828
	| decls ';'			{ LL (unLoc $1) }
829
	| decl				{ $1 }
830
	| {- empty -}			{ noLoc nilOL }
831

832
decllist :: { Located (OrdList (LHsDecl RdrName)) }
833 834 835
	: '{'            decls '}'	{ LL (unLoc $2) }
	|     vocurly    decls close	{ $2 }

836 837
-- Binding groups other than those of class and instance declarations
--
838
binds 	::  { Located (HsLocalBinds RdrName) } 		-- May have implicit parameters
839
						-- No type declarations
840 841 842
	: decllist			{ L1 (HsValBinds (cvBindGroup (unLoc $1))) }
	| '{'            dbinds '}'	{ LL (HsIPBinds (IPBinds (unLoc $2) emptyLHsBinds)) }
	|     vocurly    dbinds close	{ L (getLoc $2) (HsIPBinds (IPBinds (unLoc $2) emptyLHsBinds)) }
843

844
wherebinds :: { Located (HsLocalBinds RdrName) }	-- May have implicit parameters
845
						-- No type declarations
846
	: 'where' binds			{ LL (unLoc $2) }
847
	| {- empty -}			{ noLoc emptyLocalBinds }
848 849 850 851 852


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

853
rules	:: { OrdList (LHsDecl RdrName) }
854
	:  rules ';' rule			{ $1 `snocOL` $3 }
855
        |  rules ';'				{ $1 }
856 857
        |  rule					{ unitOL $1 }
	|  {- empty -}				{ nilOL }
858

859
rule  	:: { LHsDecl RdrName }
860
	: STRING activation rule_forall infixexp '=' exp
861 862
	     { LL $ RuleD (HsRule (getSTRING $1) 
				  ($2 `orElse` AlwaysActive) 
863
				  $3 $4 placeHolderNames $6 placeHolderNames) }
864

865 866 867
activation :: { Maybe Activation } 
        : {- empty -}                           { Nothing }
        | explicit_activation                   { Just $1 }
868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887

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)

888
deprecations :: { OrdList (LHsDecl RdrName) }
889
	: deprecations ';' deprecation		{ $1 `appOL` $3 }
890
	| deprecations ';' 			{ $1 }
891 892
	| deprecation				{ $1 }
	| {- empty -}				{ nilOL }
893 894

-- SUP: TEMPORARY HACK, not checking for `module Foo'
895
deprecation :: { OrdList (LHsDecl RdrName) }
896
	: depreclist STRING
897 898
		{ toOL [ LL $ DeprecD (Deprecation n (getSTRING $2)) 
		       | n <- unLoc $1 ] }
899 900 901 902 903 904


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

fdecl :: { LHsDecl RdrName }
Simon Marlow's avatar
Simon Marlow committed
905
fdecl : 'import' callconv safety fspec
906
		{% mkImport $2 $3 (unLoc $4) >>= return.LL }
Simon Marlow's avatar
Simon Marlow committed
907
      | 'import' callconv        fspec		
908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923
		{% 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) }
924 925
       : STRING var '::' sigtypedoc     { LL (L (getLoc $1) (getSTRING $1), $2, $4) }
       |        var '::' sigtypedoc     { LL (noLoc nilFS, $1, $3) }
926 927 928 929 930 931 932 933 934 935 936 937 938 939 940
         -- 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 }

941
sigtypes1 :: { [LHsType RdrName] }
942
	: sigtype			{ [ $1 ] }
943
	| sigtype ',' sigtypes1		{ $1 : $3 }
944 945 946 947 948

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

949 950 951 952
sigtypedoc :: { LHsType RdrName }
	: ctypedoc			{ L1 (mkImplicitHsForAllTy (noLoc []) $1) }
	-- Wrap an Implicit forall if there isn't one there already

953 954 955 956 957 958 959
sig_vars :: { Located [Located RdrName] }
	 : sig_vars ',' var		{ LL ($3 : unLoc $1) }
	 | var				{ L1 [$1] }

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

960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976
infixtype :: { LHsType RdrName }
	: btype qtyconop gentype         { LL $ HsOpTy $1 $2 $3 }
        | btype tyvarop  gentype  	 { LL $ HsOpTy $1 $2 $3 }

infixtypedoc :: { LHsType RdrName }
        : infixtype                      { $1 }
	| infixtype docprev              { LL $ HsDocTy $1 $2 }

gentypedoc :: { LHsType RdrName }
        : btype                          { $1 }
        | btypedoc                       { $1 }
        | infixtypedoc                   { $1 }
        | btype '->' ctypedoc            { LL $ HsFunTy $1 $3 }
        | btypedoc '->' ctypedoc         { LL $ HsFunTy $1 $3 }

ctypedoc  :: { LHsType RdrName }
        : 'forall' tv_bndrs '.' ctypedoc { LL $ mkExplicitHsForAllTy $2 (noLoc []) $4 }
977
        | context '=>' ctypedoc          { LL $ mkImplicitHsForAllTy   $1 $3 }
978 979 980
	-- A type of form (context => type) is an *implicit* HsForAllTy
	| gentypedoc			 { $1 }
	
981 982 983 984
strict_mark :: { Located HsBang }
	: '!'				{ L1 HsStrict }
	| '{-# UNPACK' '#-}' '!'	{ LL HsUnbox }

985 986 987 988 989 990 991 992 993 994 995
-- 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 =>
996 997 998
--
-- We have the t1 ~ t2 form here and in gentype, to permit an individual
-- equational constraint without parenthesis.
999
context :: { LHsContext RdrName }
1000 1001 1002
        : btype '~'      btype  	{% checkContext
					     (LL $ HsPredTy (HsEqualP $1 $3)) }
	| btype 			{% checkContext $1 }
1003 1004

type :: { LHsType RdrName }
1005
	: ipvar '::' gentype		{ LL (HsPredTy (HsIParam (unLoc $1) $3)) }
1006 1007 1008 1009 1010
	| gentype			{ $1 }

gentype :: { LHsType RdrName }
        : btype                         { $1 }
        | btype qtyconop gentype        { LL $ HsOpTy $1 $2 $3 }
1011
        | btype tyvarop  gentype  	{ LL $ HsOpTy $1 $2 $3 }
1012
 	| btype '->'     ctype		{ LL $ HsFunTy $1 $3 }
1013
        | btype '~'      btype  	{ LL $ HsPredTy (HsEqualP $1 $3) }
1014 1015 1016 1017 1018

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

1019 1020 1021 1022
btypedoc :: { LHsType RdrName }
	: btype atype docprev		{ LL $ HsDocTy (L (comb2 $1 $2) (HsAppTy $1 $2)) $3 }
        | atype docprev                 { LL $ HsDocTy $1 $2 }

1023 1024
atype :: { LHsType RdrName }
	: gtycon			{ L1 (HsTyVar (unLoc $1)) }
1025
	| tyvar				{ L1 (HsTyVar (unLoc $1)) }
1026
	| strict_mark atype		{ LL (HsBangTy (unLoc $1) $2) }
1027
	| '(' ctype ',' comma_types1 ')'  { LL $ HsTupleTy Boxed  ($2:$4) }
1028
	| '(#' comma_types1 '#)'	{ LL $ HsTupleTy Unboxed $2     }
1029 1030
	| '[' ctype ']'			{ LL $ HsListTy  $2 }
	| '[:' ctype ':]'		{ LL $ HsPArrTy  $2 }
1031
	| '(' ctype ')'		        { LL $ HsParTy   $2 }
1032
	| '(' ctype '::' kind ')'	{ LL $ HsKindSig $2 (unLoc $4) }
1033 1034 1035 1036 1037 1038 1039 1040
-- 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 }
1041
	: sigtype			{% checkInstType $1 }
1042

1043 1044 1045 1046
inst_types1 :: { [LHsType RdrName] }
	: inst_type			{ [$1] }
	| inst_type ',' inst_types1	{ $1 : $3 }

1047 1048 1049 1050 1051
comma_types0  :: { [LHsType RdrName] }
	: comma_types1			{ $1 }
	| {- empty -}			{ [] }

comma_types1	:: { [LHsType RdrName] }
1052 1053
	: ctype				{ [$1] }
	| ctype  ',' comma_types1	{ $1 : $3 }
1054 1055 1056 1057 1058 1059 1060

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

tv_bndr :: { LHsTyVarBndr RdrName }
	: tyvar				{ L1 (UserTyVar (unLoc $1)) }
1061 1062
	| '(' tyvar '::' kind ')'	{ LL (KindedTyVar (unLoc $2) 
							  (unLoc $4)) }
1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082

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

1083
kind	:: { Located Kind }
1084
	: akind			{ $1 }
1085
	| akind '->' kind	{ LL (mkArrowKind (unLoc $1) (unLoc $3)) }
1086

1087 1088 1089 1090
akind	:: { Located Kind }
	: '*'			{ L1 liftedTypeKind }
	| '!'			{ L1 unliftedTypeKind }
	| '(' kind ')'		{ LL (unLoc $2) }
1091 1092 1093 1094 1095


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

1096 1097 1098 1099 1100 1101
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) }
1102
        | gadt_constrs ';' 		{ $1 }
1103 1104
        | gadt_constr                   { L1 [$1] } 

1105 1106 1107 1108 1109 1110
-- 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

1111
gadt_constr :: { LConDecl RdrName }
1112
        : con '::' sigtype
1113 1114 1115
              { LL (mkGadtDecl $1 $3) } 
        -- Syntax: Maybe merge the record stuff with the single-case above?
        --         (to kill the mostly harmless reduce/reduce error)
1116
        -- XXX revisit audreyt
1117 1118
	| constr_stuff_record '::' sigtype
		{ let (con,details) = unLoc $1 in 
1119
		  LL (ConDecl con Implicit [] (noLoc []) details (ResTyGADT $3) Nothing) }
1120 1121 1122
{-
	| forall context '=>' constr_stuff_record '::' sigtype
		{ let (con,details) = unLoc $4 in 
1123
		  LL (ConDecl con Implicit (unLoc $1) $2 details (ResTyGADT $6) Nothing ) }
1124 1125
	| forall constr_stuff_record '::' sigtype
		{ let (con,details) = unLoc $2 in 
1126
		  LL (ConDecl con Implicit (unLoc $1) (noLoc []) details (ResTyGADT $4) Nothing) }
1127 1128
-}

1129 1130 1131

constrs :: { Located [LConDecl RdrName] }
        : {- empty; a GHC extension -}  { noLoc [] }
1132
        | maybe_docnext '=' constrs1    { L (comb2 $2 $3) (addConDocs (unLoc $3) $1) }
1133 1134

constrs1 :: { Located [LConDecl RdrName] }
1135 1136
	: constrs1 maybe_docnext '|' maybe_docprev constr { LL (addConDoc $5 $2 : addConDocFirst (unLoc $1) $4) }
	| constr			                  { L1 [$1] }
1137 1138

constr :: { LConDecl RdrName }
1139 1140 1141 1142 1143 1144
	: maybe_docnext forall context '=>' constr_stuff maybe_docprev	
		{ let (con,details) = unLoc $5 in 
		  L (comb4 $2 $3 $4 $5) (ConDecl con Explicit (unLoc $2) $3 details ResTyH98 ($1 `mplus` $6)) }
	| maybe_docnext forall constr_stuff maybe_docprev
		{ let (con,details) = unLoc $3 in 
		  L (comb2 $2 $3) (ConDecl con Explicit (unLoc $2) (noLoc []) details ResTyH98 ($1 `mplus` $4)) }
1145 1146 1147 1148 1149

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

1150
constr_stuff :: { Located (Located RdrName, HsConDeclDetails RdrName) }
1151 1152 1153 1154 1155 1156 1157
-- 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)
1158 1159 1160
	: btype				{% mkPrefixCon $1 [] >>= return.LL }
	| oqtycon '{' '}' 		{% mkRecCon $1 [] >>= return.LL }
	| oqtycon '{' fielddecls '}' 	{% mkRecCon $1 $3 >>= return.LL }
1161
	| btype conop btype		{ LL ($2, InfixCon $1 $3) }
1162

1163
constr_stuff_record :: { Located (Located RdrName, HsConDeclDetails RdrName) }
1164 1165 1166
	: oqtycon '{' '}' 		{% mkRecCon $1 [] >>= return.sL (comb2 $1 $>) }
	| oqtycon '{' fielddecls '}' 	{% mkRecCon $1 $3 >>= return.sL (comb2 $1 $>) }

1167 1168 1169
fielddecls :: { [([Located RdrName], LBangType RdrName, Maybe (LHsDoc RdrName))] }
	: fielddecl maybe_docnext ',' maybe_docprev fielddecls { addFieldDoc (unLoc $1) $4 : addFieldDocs $5 $2 }
	| fielddecl			                       { [unLoc $1] }
1170

1171 1172
fielddecl :: { Located ([Located RdrName], LBangType RdrName, Maybe (LHsDoc RdrName)) }
	: maybe_docnext sig_vars '::' ctype maybe_docprev      { L (comb3 $2 $3 $4) (reverse (unLoc $2), $4, $1 `mplus` $5) }
1173

1174 1175 1176 1177
-- 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.
1178 1179
deriving :: { Located (Maybe [LHsType RdrName]) }
	: {- empty -}				{ noLoc Nothing }
1180 1181 1182
	| 'deriving' qtycon	{% do { let { L loc tv = $2 }
				      ; p <- checkInstType (L loc (HsTyVar tv))
				      ; return (LL (Just [p])) } }
1183 1184
	| 'deriving' '(' ')'	 		{ LL (Just []) }
	| 'deriving' '(' inst_types1 ')' 	{ LL (Just $3) }
1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210
             -- 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.
-}

1211 1212 1213 1214 1215 1216 1217 1218 1219
docdecl :: { LHsDecl RdrName }
        : docdecld { L1 (DocD (unLoc $1)) }

docdecld :: { LDocDecl RdrName }
        : 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) }

1220
decl 	:: { Located (OrdList (LHsDecl RdrName)) }
1221
	: sigdecl			{ $1 }
1222
	| '!' aexp rhs			{% do { pat <- checkPattern $2;
1223
					        return (LL $ unitOL $ LL $ ValD ( 
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
1224
							PatBind (LL $ BangPat pat) (unLoc $3)
1225
								placeHolderType placeHolderNames)) } }
Ian Lynagh's avatar
Ian Lynagh committed
1226 1227 1228
        | infixexp opt_sig rhs          {% do { r <- checkValDef $1 $2 $3;
                                                let { l = comb2 $1 $> };
                                                return $! (sL l (unitOL $! (sL l $ ValD r))) } }
1229
        | docdecl                       { LL $ unitOL $1 }
1230 1231

rhs	:: { Located (GRHSs RdrName) }
Ian Lynagh's avatar
Ian Lynagh committed
1232
	: '=' exp wherebinds	{ sL (comb3 $1 $2 $3) $ GRHSs (unguardedRHS $2) (unLoc $3) }
1233
	| gdrhs	wherebinds	{ LL $ GRHSs (reverse (unLoc $1)) (unLoc $2) }
1234 1235 1236 1237 1238 1239

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

gdrh :: { LGRHS RdrName }
1240
	: '|' guardquals '=' exp  	{ sL (comb2 $1 $>) $ GRHS (unLoc $2) $4 }
1241

1242
sigdecl :: { Located (OrdList (LHsDecl RdrName)) }
1243
	: infixexp '::' sigtypedoc
1244
				{% do s <- checkValSig $1 $3; 
1245
				      return (LL $ unitOL (LL $ SigD s)) }
1246
		-- See the above notes for why we need infixexp here
1247
	| var ',' sig_vars '::' sigtypedoc
1248
				{ LL $ toOL [ LL $ SigD (TypeSig n $5) | n <- $1 : unLoc $3 ] }
1249
	| infix prec ops	{ LL $ toOL [ LL $ SigD (FixSig (FixitySig n (Fixity $2 (unLoc $1))))
1250 1251
					     | n <- unLoc $3 ] }
	| '{-# INLINE'   activation qvar '#-}'	      
1252
				{ LL $ unitOL (LL $ SigD (InlineSig $3 (mkInlineSpec $2 (getINLINE $1)))) }
1253
	| '{-# SPECIALISE' qvar '::' sigtypes1 '#-}'
1254
			 	{ LL $ toOL [ LL $ SigD (SpecSig $2 t defaultInlineSpec) 
1255
					    | t <- $4] }
1256
	| '{-# SPECIALISE_INLINE' activation qvar '::' sigtypes1 '#-}'
1257
			 	{ LL $ toOL [ LL $ SigD (SpecSig $3 t (mkInlineSpec $2 (getSPEC_INLINE $1)))
1258
					    | t <- $5] }
1259
	| '{-# SPECIALISE' 'instance' inst_type '#-}'
1260
				{ LL $ unitOL (LL $ SigD (SpecInstSig $3)) }
1261 1262 1263 1264 1265 1266

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

exp   :: { LHsExpr RdrName }
	: infixexp '::' sigtype		{ LL $ ExprWithTySig $1 $3 }
1267 1268 1269 1270
	| 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}
1271 1272 1273 1274 1275 1276 1277
	| infixexp			{ $1 }

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

exp10 :: { LHsExpr RdrName }
1278 1279 1280 1281
	: '\\' apat apats opt_asig '->' exp	
			{ LL $ HsLam (mkMatchGroup [LL $ Match ($2:$3) $4
							   	(unguardedGRHSs $6)
							    ]) }
1282 1283
  	| 'let' binds 'in' exp			{ LL $ HsLet (unLoc $2) $4 }
	| 'if' exp 'then' exp 'else' exp	{ LL $ HsIf $2 $4 $6 }
1284
   	| 'case' exp 'of' altslist		{ LL $ HsCase $2 (mkMatchGroup (unLoc $4)) }
1285
	| '-' fexp				{ LL $ NegApp $2 noSyntaxExpr }
1286 1287

  	| 'do' stmtlist			{% let loc = comb2 $1 $2 in
1288 1289
					   checkDo loc (unLoc $2)  >>= \ (stmts,body) ->
					   return (L loc (mkHsDo DoExpr stmts body)) }