Parser.y.pp 75.8 KB
Newer Older
1 2 3 4 5 6 7 8 9 10
--								-*-haskell-*-
-- ---------------------------------------------------------------------------
-- (c) The University of Glasgow 1997-2003
---
-- The GHC grammar.
--
-- Author(s): Simon Marlow, Sven Panne 1997, 1998, 1999
-- ---------------------------------------------------------------------------

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

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

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

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

import FastString
import Maybes		( orElse )
import Outputable
59

60
import Control.Monad    ( unless )
Simon Marlow's avatar
Simon Marlow committed
61
import GHC.Exts
62 63
import Data.Char
import Control.Monad    ( mplus )
64 65 66
}

{-
67 68 69 70 71 72 73 74 75 76 77
-----------------------------------------------------------------------------
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

78 79 80 81 82 83 84 85 86 87 88
-----------------------------------------------------------------------------
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

89 90 91 92 93 94 95 96 97 98 99
-----------------------------------------------------------------------------
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

100 101 102 103 104 105 106 107 108 109 110
-----------------------------------------------------------------------------
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

111
-----------------------------------------------------------------------------
112
Conflicts: 38 shift/reduce (1.25)
113

114
10 for abiguity in 'if x then y else z + 1'		[State 178]
115 116 117
	(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

118
1 for ambiguity in 'if x then y else z :: T'		[State 178]
119 120
	(shift parses as 'if x then y else (z :: T)', as per longest-parse rule)

121
4 for ambiguity in 'if x then y else z -< e'		[State 178]
122
	(shift parses as 'if x then y else (z -< T)', as per longest-parse rule)
123 124 125 126 127 128 129 130 131 132
	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 ...
133

134
10 for ambiguity in 'e :: a `b` c'.  Does this mean 	[States 11, 253]
135 136
	(e::a) `b` c, or 
	(e :: (a `b` c))
137
    As well as `b` we can have !, VARSYM, QCONSYM, and CONSYM, hence 5 cases
138
    Same duplication between states 11 and 253 as the previous case
139

140
1 for ambiguity in 'let ?x ...'				[State 329]
141 142 143 144
	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.

145
1 for ambiguity in '{-# RULES "name" [ ... #-}		[State 382]
146 147 148 149
	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

150
1 for ambiguity in '{-# RULES "name" forall = ... #-}' 	[State 474]
151 152 153 154 155 156 157
	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'.

158 159 160 161
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.   

162 163 164 165 166 167 168 169 170 171 172
-- ---------------------------------------------------------------------------
-- 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
173
     -- This doesn't seem to work anymore -=chak
174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235

   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

236
 'forall'	{ L _ ITforall }		-- GHC extension keywords
237 238 239 240 241
 'foreign'	{ L _ ITforeign }
 'export'	{ L _ ITexport }
 'label'	{ L _ ITlabel } 
 'dynamic'	{ L _ ITdynamic }
 'safe'		{ L _ ITsafe }
242
 'interruptible' { L _ ITinterruptible }
243 244
 'unsafe'	{ L _ ITunsafe }
 'mdo'		{ L _ ITmdo }
245
 'family'	{ L _ ITfamily }
246 247
 'stdcall'      { L _ ITstdcallconv }
 'ccall'        { L _ ITccallconv }
248
 'prim'         { L _ ITprimcallconv }
249 250
 'proc'		{ L _ ITproc }		-- for arrow notation extension
 'rec'		{ L _ ITrec }		-- for arrow notation extension
251 252 253
 'group'    { L _ ITgroup }     -- for list transform extension
 'by'       { L _ ITby }        -- for list transform extension
 'using'    { L _ ITusing }     -- for list transform extension
254

255 256
 '{-# INLINE'             { L _ (ITinline_prag _ _) }
 '{-# SPECIALISE'         { L _ ITspec_prag }
257
 '{-# SPECIALISE_INLINE'  { L _ (ITspec_inline_prag _) }
258 259 260 261 262 263 264 265 266
 '{-# SOURCE'      				{ L _ ITsource_prag }
 '{-# RULES'       				{ L _ ITrules_prag }
 '{-# CORE'        				{ L _ ITcore_prag }              -- hdaume: annotated core
 '{-# SCC'                { L _ ITscc_prag }
 '{-# GENERATED'          { L _ ITgenerated_prag }
 '{-# DEPRECATED'         { L _ ITdeprecated_prag }
 '{-# WARNING'            { L _ ITwarning_prag }
 '{-# UNPACK'             { L _ ITunpack_prag }
 '{-# ANN'                { L _ ITann_prag }
267 268
 '{-# VECTORISE'          { L _ ITvect_prag }
 '{-# VECTORISE_SCALAR'   { L _ ITvect_scalar_prag }
269 270
 '{-# NOVECTORISE'        { L _ ITnovect_prag }
 '#-}'             				{ L _ ITclose_prag }
271 272 273 274 275 276 277 278 279 280 281

 '..'		{ L _ ITdotdot }  			-- reserved symbols
 ':'		{ L _ ITcolon }
 '::'		{ L _ ITdcolon }
 '='		{ L _ ITequal }
 '\\'		{ L _ ITlam }
 '|'		{ L _ ITvbar }
 '<-'		{ L _ ITlarrow }
 '->'		{ L _ ITrarrow }
 '@'		{ L _ ITat }
 '~'		{ L _ ITtilde }
batterseapower's avatar
batterseapower committed
282
 '~#'		{ L _ ITtildehsh }
283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320
 '=>'		{ 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  _) }
321 322
 PREFIXQVARSYM  { L _ (ITprefixqvarsym  _) }
 PREFIXQCONSYM  { L _ (ITprefixqconsym  _) }
323 324 325 326 327 328 329 330 331 332 333

 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
334
 PRIMWORD 	{ L _ (ITprimword  _) }
335 336
 PRIMFLOAT	{ L _ (ITprimfloat  _) }
 PRIMDOUBLE	{ L _ (ITprimdouble _) }
337 338 339 340 341 342

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

343 344 345 346 347 348 349 350 351 352
-- 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
353
TH_QUASIQUOTE	{ L _ (ITquasiQuote _) }
354 355 356 357 358 359

%monad { P } { >>= } { return }
%lexer { lexer } { L _ ITeof }
%name parseModule module
%name parseStmt   maybe_stmt
%name parseIdentifier  identifier
360
%name parseType ctype
361
%partial parseHeader header
362
%tokentype { (Located Token) }
363 364
%%

365 366 367 368 369 370 371
-----------------------------------------------------------------------------
-- Identifiers; one of the entry points
identifier :: { Located RdrName }
	: qvar				{ $1 }
	| qcon				{ $1 }
	| qvarop			{ $1 }
	| qconop			{ $1 }
372
    | '(' '->' ')'      { LL $ getRdrName funTyCon }
373

374 375 376 377 378 379 380 381 382 383 384
-----------------------------------------------------------------------------
-- Module Header

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

module 	:: { Located (HsModule RdrName) }
Ian Lynagh's avatar
Ian Lynagh committed
385
 	: maybedocheader 'module' modid maybemodwarning maybeexports 'where' body
386 387 388
		{% fileSrcSpan >>= \ loc ->
		   return (L loc (HsModule (Just $3) $5 (fst $7) (snd $7) $4 $1
                          ) )}
389
        | body2
390
		{% fileSrcSpan >>= \ loc ->
David Waern's avatar
David Waern committed
391
		   return (L loc (HsModule Nothing Nothing
392 393
                          (fst $1) (snd $1) Nothing Nothing
                          )) }
394

395
maybedocheader :: { Maybe LHsDocString }
396
        : moduleheader            { $1 }
397
        | {- empty -}             { Nothing }
398 399 400 401

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

Ian Lynagh's avatar
Ian Lynagh committed
402
maybemodwarning :: { Maybe WarningTxt }
403 404
    : '{-# DEPRECATED' strings '#-}' { Just (DeprecatedTxt $ unLoc $2) }
    | '{-# WARNING' strings '#-}'    { Just (WarningTxt $ unLoc $2) }
Ian Lynagh's avatar
Ian Lynagh committed
405
    |  {- empty -}                  { Nothing }
406 407 408 409 410

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

411 412 413 414
body2 	:: { ([LImportDecl RdrName], [LHsDecl RdrName]) }
	:  '{' top '}'          		{ $2 }
 	|  missing_module_keyword top close     { $2 }

415 416 417 418 419 420 421 422
top 	:: { ([LImportDecl RdrName], [LHsDecl RdrName]) }
	: importdecls				{ (reverse $1,[]) }
	| importdecls ';' cvtopdecls		{ (reverse $1,$3) }
	| cvtopdecls				{ ([],$1) }

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

423 424 425 426
-----------------------------------------------------------------------------
-- Module declaration & imports only

header 	:: { Located (HsModule RdrName) }
Ian Lynagh's avatar
Ian Lynagh committed
427
 	: maybedocheader 'module' modid maybemodwarning maybeexports 'where' header_body
428 429 430
		{% fileSrcSpan >>= \ loc ->
		   return (L loc (HsModule (Just $3) $5 $7 [] $4 $1
                          ))}
431
        | header_body2
432
		{% fileSrcSpan >>= \ loc ->
433
                   return (L loc (HsModule Nothing Nothing $1 [] Nothing
434
                          Nothing)) }
435 436 437

header_body :: { [LImportDecl RdrName] }
	:  '{'            importdecls		{ $2 }
438 439 440 441 442
        |      vocurly    importdecls           { $2 }

header_body2 :: { [LImportDecl RdrName] }
        :  '{' importdecls                      { $2 }
        |  missing_module_keyword importdecls   { $2 }
443

444 445 446 447 448 449 450
-----------------------------------------------------------------------------
-- The Export List

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

451 452
exportlist :: { [LIE RdrName] }
	: expdoclist ',' expdoclist		{ $1 ++ $3 }
453 454 455
	| exportlist1				{ $1 }

exportlist1 :: { [LIE RdrName] }
456 457 458 459 460 461 462 463 464 465 466 467 468
        : 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)) }       
                       
469 470 471 472 473 474 475 476 477 478 479
   -- 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] }
480 481
	:  qcnames ',' qcname_ext	{ unLoc $3 : $1 }
	|  qcname_ext			{ [unLoc $1]  }
482

483 484 485 486 487 488 489 490
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.
491
qcname 	:: { Located RdrName }	-- Variable or data constructor
492 493
	:  qvar				{ $1 }
	|  qcon				{ $1 }
494 495 496 497 498 499 500 501 502 503 504 505 506 507

-----------------------------------------------------------------------------
-- 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 }
508
	: 'import' maybe_src maybe_safe optqualified maybe_pkg modid maybeas maybeimpspec 
509 510 511 512 513
		{ L (comb4 $1 $6 $7 $8) $
                  ImportDecl { ideclName = $6, ideclPkgQual = $5
                             , ideclSource = $2, ideclSafe = $3
                             , ideclQualified = $4, ideclImplicit = False
                             , ideclAs = unLoc $7, ideclHiding = unLoc $8 } }
514 515 516 517 518

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

519 520 521 522
maybe_safe :: { Bool }
	: 'safe'				{ True }
	| {- empty -}				{ False }

523 524 525 526
maybe_pkg :: { Maybe FastString }
        : STRING                                { Just (getSTRING $1) }
        | {- empty -}                           { Nothing }

527 528 529 530
optqualified :: { Bool }
      	: 'qualified'                           { True  }
      	| {- empty -}				{ False }

Simon Marlow's avatar
Simon Marlow committed
531
maybeas :: { Located (Maybe ModuleName) }
532 533 534 535 536 537 538 539
      	: '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]) }
540 541
	:  '(' exportlist ')'  			{ LL (False, $2) }
	|  'hiding' '(' exportlist ')' 		{ LL (True,  $3) }
542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561

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

562
topdecls :: { OrdList (LHsDecl RdrName) }
563 564 565
        : topdecls ';' topdecl                  { $1 `appOL` $3 }
        | topdecls ';'                          { $1 }
        | topdecl                               { $1 }
566

567
topdecl :: { OrdList (LHsDecl RdrName) }
568 569
        : cl_decl                               { unitOL (L1 (TyClD (unLoc $1))) }
        | ty_decl                               { unitOL (L1 (TyClD (unLoc $1))) }
570 571 572 573
        | '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)))}
574
        | stand_alone_deriving                  { unitOL (LL (DerivD (unLoc $1))) }
575 576
        | 'default' '(' comma_types0 ')'        { unitOL (LL $ DefD (DefaultDecl $3)) }
        | 'foreign' fdecl                       { unitOL (LL (unLoc $2)) }
577 578
        | '{-# DEPRECATED' deprecations '#-}'   { $2 }
        | '{-# WARNING' warnings '#-}'          { $2 }
579
        | '{-# RULES' rules '#-}'               { $2 }
580 581 582 583 584 585 586
        | '{-# VECTORISE_SCALAR' qvar '#-}'     { unitOL $ LL $ VectD (HsVect       $2 Nothing) }
        | '{-# VECTORISE' qvar '=' exp '#-}'    { unitOL $ LL $ VectD (HsVect       $2 (Just $4)) }
        | '{-# NOVECTORISE' qvar '#-}'          { unitOL $ LL $ VectD (HsNoVect     $2) }
        | '{-# VECTORISE_SCALAR' 'type' qtycon '#-}'     
                                                { unitOL $ LL $ VectD (HsVectTypeIn $3 Nothing) }
        | '{-# VECTORISE' 'type' qtycon '=' ctype '#-}'     
                                                { unitOL $ LL $ VectD (HsVectTypeIn $3 (Just $5)) }
587 588 589 590 591 592 593 594
        | annotation { unitOL $1 }
        | decl                                  { unLoc $1 }

        -- Template Haskell Extension
        -- The $(..) form is one possible form of infixexp
        -- but we treat an arbitrary expression just as if 
        -- it had a $(..) wrapped around it
        | infixexp                              { unitOL (LL $ mkTopSpliceDecl $1) } 
595

596 597 598
-- Type classes
--
cl_decl :: { LTyClDecl RdrName }
599
	: 'class' tycl_hdr fds where_cls	{% mkClassDecl (comb4 $1 $2 $3 $4) $2 $3 $4 }
600

601
-- Type declarations (toplevel)
602 603
--
ty_decl :: { LTyClDecl RdrName }
604
           -- ordinary type synonyms
605
        : 'type' type '=' ctypedoc
606 607 608 609
		-- 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
610 611
	        --
		-- Note the use of type for the head; this allows
612
		-- infix type constructors to be declared 
613
 		{% mkTySynonym (comb2 $1 $4) False $2 $4 }
614 615

           -- type family declarations
616
        | 'type' 'family' type opt_kind_sig 
617 618
		-- Note the use of type for the head; this allows
		-- infix type constructors to be declared
619
 		{% mkTyFamily (comb3 $1 $3 $4) TypeFamily $3 (unLoc $4) }
620 621 622 623 624

           -- type instance declarations
        | 'type' 'instance' type '=' ctype
		-- Note the use of type for the head; this allows
		-- infix type constructors and type patterns
625
 		{% mkTySynonym (comb2 $1 $5) True $3 $5 }
626

627
          -- ordinary data type or newtype declaration
628
	| data_or_newtype tycl_hdr constrs deriving
629 630
		{% mkTyData (comb4 $1 $2 $3 $4) (unLoc $1) False $2 
                            Nothing (reverse (unLoc $3)) (unLoc $4) }
631 632
			           -- We need the location on tycl_hdr in case 
				   -- constrs and deriving are both empty
633

634
          -- ordinary GADT declaration
635
        | data_or_newtype tycl_hdr opt_kind_sig 
636
		 gadt_constrlist
637
		 deriving
638
		{% mkTyData (comb4 $1 $2 $4 $5) (unLoc $1) False $2 
639
                            (unLoc $3) (unLoc $4) (unLoc $5) }
640 641
			           -- We need the location on tycl_hdr in case 
				   -- constrs and deriving are both empty
642

643
          -- data/newtype family
644 645
        | 'data' 'family' type opt_kind_sig
		{% mkTyFamily (comb3 $1 $2 $4) DataFamily $3 (unLoc $4) }
646

647
          -- data/newtype instance declaration
648
	| data_or_newtype 'instance' tycl_hdr constrs deriving
649 650
		{% mkTyData (comb4 $1 $3 $4 $5) (unLoc $1) True $3
			    Nothing (reverse (unLoc $4)) (unLoc $5) }
651

652
          -- GADT instance declaration
653
        | data_or_newtype 'instance' tycl_hdr opt_kind_sig 
654
	         gadt_constrlist
655
		 deriving
656 657
		{% mkTyData (comb4 $1 $3 $5 $6) (unLoc $1) True $3
			    (unLoc $4) (unLoc $5) (unLoc $6) }
658 659

-- Associated type family declarations
660 661 662 663 664 665 666
--
-- * 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. 
667
--
668
at_decl_cls :: { LTyClDecl RdrName }
669
           -- type family declarations
670
        : 'type' type opt_kind_sig
671 672
		-- Note the use of type for the head; this allows
		-- infix type constructors to be declared
673
 		{% mkTyFamily (comb3 $1 $2 $3) TypeFamily $2 (unLoc $3) }
674

675 676 677 678 679 680
           -- default type instance
        | 'type' type '=' ctype
		-- Note the use of type for the head; this allows
		-- infix type constructors and type patterns
 		{% mkTySynonym (comb2 $1 $4) True $2 $4 }

681
          -- data/newtype family declaration
682 683 684 685
        | 'data' type opt_kind_sig
		{% mkTyFamily (comb3 $1 $2 $3) DataFamily $2 (unLoc $3) }

-- Associated type instances
686 687 688 689 690 691
--
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
692
 		{% mkTySynonym (comb2 $1 $4) True $2 $4 }
693 694 695

        -- data/newtype instance declaration
	| data_or_newtype tycl_hdr constrs deriving
696 697
		{% mkTyData (comb4 $1 $2 $3 $4) (unLoc $1) True $2 
                            Nothing (reverse (unLoc $3)) (unLoc $4) }
698 699 700

        -- GADT instance declaration
        | data_or_newtype tycl_hdr opt_kind_sig 
701
		 gadt_constrlist
702
		 deriving
703 704
		{% mkTyData (comb4 $1 $2 $4 $5) (unLoc $1) True $2 
		   	    (unLoc $3) (unLoc $4) (unLoc $5) }
705

706 707 708 709
data_or_newtype :: { Located NewOrData }
	: 'data'	{ L1 DataType }
	| 'newtype'	{ L1 NewType }

710 711 712
opt_kind_sig :: { Located (Maybe Kind) }
	: 				{ noLoc Nothing }
	| '::' kind			{ LL (Just (unLoc $2)) }
713

714
-- tycl_hdr parses the header of a class or data type decl,
715 716 717 718
-- which takes the form
--	T a b
-- 	Eq a => T a
--	(Eq a, Ord b) => T a b
719
--      T Int [a]			-- for associated types
720
-- Rather a lot of inlining here, else we get reduce/reduce errors
721 722 723
tycl_hdr :: { Located (Maybe (LHsContext RdrName), LHsType RdrName) }
	: context '=>' type		{ LL (Just $1, $3) }
	| type                          { L1 (Nothing, $1) }
724

725 726 727 728 729
-----------------------------------------------------------------------------
-- Stand-alone deriving

-- Glasgow extension: stand-alone deriving declarations
stand_alone_deriving :: { LDerivDecl RdrName }
730
  	: 'deriving' 'instance' inst_type { LL (DerivDecl $3) }
731

732 733 734
-----------------------------------------------------------------------------
-- Nested declarations

735
-- Declaration in class bodies
736
--
737 738 739 740
decl_cls  :: { Located (OrdList (LHsDecl RdrName)) }
decl_cls  : at_decl_cls		        { LL (unitOL (L1 (TyClD (unLoc $1)))) }
	  | decl                        { $1 }

741 742 743 744 745
	  -- A 'default' signature used with the generic-programming extension
          | 'default' infixexp '::' sigtypedoc
                    {% do { (TypeSig l ty) <- checkValSig $2 $4
                          ; return (LL $ unitOL (LL $ SigD (GenericSig l ty))) } }

746 747 748 749 750
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 }
751 752


753
decllist_cls
754
        :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
755 756
	: '{'         decls_cls '}'	{ LL (unLoc $2) }
	|     vocurly decls_cls close	{ $2 }
757

758
-- Class body
759
--
760
where_cls :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
761 762
				-- No implicit parameters
				-- May have type declarations
763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788
	: '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) }
789 790
	| {- empty -}			{ noLoc nilOL }

791 792
-- Declarations in binding groups other than classes and instances
--
793
decls 	:: { Located (OrdList (LHsDecl RdrName)) }	
Ian Lynagh's avatar
Ian Lynagh committed
794 795
	: decls ';' decl		{ let { this = unLoc $3;
                                    rest = unLoc $1;
Ian Lynagh's avatar
Ian Lynagh committed
796
                                    these = rest `appOL` this }
Ian Lynagh's avatar
Ian Lynagh committed
797 798
                              in rest `seq` this `seq` these `seq`
                                    LL these }
799
	| decls ';'			{ LL (unLoc $1) }
800
	| decl				{ $1 }
801
	| {- empty -}			{ noLoc nilOL }
802

803
decllist :: { Located (OrdList (LHsDecl RdrName)) }
804 805 806
	: '{'            decls '}'	{ LL (unLoc $2) }
	|     vocurly    decls close	{ $2 }

807 808
-- Binding groups other than those of class and instance declarations
--
809
binds 	::  { Located (HsLocalBinds RdrName) } 		-- May have implicit parameters
810
						-- No type declarations
811
	: decllist			{ L1 (HsValBinds (cvBindGroup (unLoc $1))) }
812 813
	| '{'            dbinds '}'	{ LL (HsIPBinds (IPBinds (unLoc $2) emptyTcEvBinds)) }
	|     vocurly    dbinds close	{ L (getLoc $2) (HsIPBinds (IPBinds (unLoc $2) emptyTcEvBinds)) }
814

815
wherebinds :: { Located (HsLocalBinds RdrName) }	-- May have implicit parameters
816
						-- No type declarations
817
	: 'where' binds			{ LL (unLoc $2) }
818
	| {- empty -}			{ noLoc emptyLocalBinds }
819 820 821 822 823


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

824
rules	:: { OrdList (LHsDecl RdrName) }
825
	:  rules ';' rule			{ $1 `snocOL` $3 }
826
        |  rules ';'				{ $1 }
827 828
        |  rule					{ unitOL $1 }
	|  {- empty -}				{ nilOL }
829

830
rule  	:: { LHsDecl RdrName }
831
	: STRING activation rule_forall infixexp '=' exp
832 833
	     { LL $ RuleD (HsRule (getSTRING $1) 
				  ($2 `orElse` AlwaysActive) 
834
				  $3 $4 placeHolderNames $6 placeHolderNames) }
835

836 837 838
activation :: { Maybe Activation } 
        : {- empty -}                           { Nothing }
        | explicit_activation                   { Just $1 }
839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856

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

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

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

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

-----------------------------------------------------------------------------
Ian Lynagh's avatar
Ian Lynagh committed
857 858 859 860 861 862 863 864 865 866
-- Warnings and deprecations (c.f. rules)

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

-- SUP: TEMPORARY HACK, not checking for `module Foo'
warning :: { OrdList (LHsDecl RdrName) }
867 868
	: namelist strings
		{ toOL [ LL $ WarningD (Warning n (WarningTxt $ unLoc $2))
Ian Lynagh's avatar
Ian Lynagh committed
869
		       | n <- unLoc $1 ] }
870

871
deprecations :: { OrdList (LHsDecl RdrName) }
872
	: deprecations ';' deprecation		{ $1 `appOL` $3 }
873
	| deprecations ';' 			{ $1 }
874 875
	| deprecation				{ $1 }
	| {- empty -}				{ nilOL }
876 877

-- SUP: TEMPORARY HACK, not checking for `module Foo'
878
deprecation :: { OrdList (LHsDecl RdrName) }
879 880
	: namelist strings
		{ toOL [ LL $ WarningD (Warning n (DeprecatedTxt $ unLoc $2))
881
		       | n <- unLoc $1 ] }
882

883 884 885 886 887 888 889 890
strings :: { Located [FastString] }
    : STRING { L1 [getSTRING $1] }
    | '[' stringlist ']' { LL $ fromOL (unLoc $2) }

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

891 892 893 894 895 896 897
-----------------------------------------------------------------------------
-- Annotations
annotation :: { LHsDecl RdrName }
    : '{-# ANN' name_var aexp '#-}'      { LL (AnnD $ HsAnnotation (ValueAnnProvenance (unLoc $2)) $3) }
    | '{-# ANN' 'type' tycon aexp '#-}'  { LL (AnnD $ HsAnnotation (TypeAnnProvenance (unLoc $3)) $4) }
    | '{-# ANN' 'module' aexp '#-}'      { LL (AnnD $ HsAnnotation ModuleAnnProvenance $3) }

898 899 900 901 902

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

fdecl :: { LHsDecl RdrName }
Simon Marlow's avatar
Simon Marlow committed
903
fdecl : 'import' callconv safety fspec
904
		{% mkImport $2 $3 (unLoc $4) >>= return.LL }
Simon Marlow's avatar
Simon Marlow committed
905
      | 'import' callconv        fspec		
Ian Lynagh's avatar
Ian Lynagh committed
906
		{% do { d <- mkImport $2 PlaySafe (unLoc $3);
907 908 909 910
			return (LL d) } }
      | 'export' callconv fspec
		{% mkExport $2 (unLoc $3) >>= return.LL }

911 912 913 914
callconv :: { CCallConv }
	  : 'stdcall'			{ StdCallConv }
	  | 'ccall'			{ CCallConv   }
	  | 'prim'			{ PrimCallConv}
915 916 917

safety :: { Safety }
	: 'unsafe'			{ PlayRisky }
Ian Lynagh's avatar
Ian Lynagh committed
918
	| 'safe'			{ PlaySafe }
919
	| 'interruptible'		{ PlayInterruptible }
920 921

fspec :: { Located (Located FastString, Located RdrName, LHsType RdrName) }
922 923
       : STRING var '::' sigtypedoc     { LL (L (getLoc $1) (getSTRING $1), $2, $4) }
       |        var '::' sigtypedoc     { LL (noLoc nilFS, $1, $3) }
924 925 926 927 928 929 930 931 932 933 934 935 936 937 938
         -- 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 }

939 940
sigtype :: { LHsType RdrName }		-- Always a HsForAllTy,
                                        -- to tell the renamer where to generalise
941 942 943
	: ctype				{ L1 (mkImplicitHsForAllTy (noLoc []) $1) }
	-- Wrap an Implicit forall if there isn't one there already

944
sigtypedoc :: { LHsType RdrName }       -- Always a HsForAllTy
945 946 947
	: ctypedoc			{ L1 (mkImplicitHsForAllTy (noLoc []) $1) }
	-- Wrap an Implicit forall if there isn't one there already

948 949 950 951
sig_vars :: { Located [Located RdrName] }
	 : sig_vars ',' var		{ LL ($3 : unLoc $1) }
	 | var				{ L1 [$1] }

952 953 954 955
sigtypes1 :: { [LHsType RdrName] }	-- Always HsForAllTys
	: sigtype			{ [ $1 ] }
	| sigtype ',' sigtypes1		{ $1 : $3 }

956 957 958
-----------------------------------------------------------------------------
-- Types

959
infixtype :: { LHsType RdrName }
waern's avatar
waern committed
960 961
	: btype qtyconop type         { LL $ HsOpTy $1 $2 $3 }
        | btype tyvarop  type  	 { LL $ HsOpTy $1 $2 $3 }
962

963 964
strict_mark :: { Located HsBang }
	: '!'				{ L1 HsStrict }
965
	| '{-# UNPACK' '#-}' '!'	{ LL HsUnpack }
966

967 968 969
-- A ctype is a for-all type
ctype	:: { LHsType RdrName }
	: 'forall' tv_bndrs '.' ctype	{ LL $ mkExplicitHsForAllTy $2 (noLoc []) $4 }
waern's avatar
waern committed
970
	| context '=>' ctype		{ LL $ mkImplicitHsForAllTy   $1 $3 }
971
	-- A type of form (context => type) is an *implicit* HsForAllTy
batterseapower's avatar
batterseapower committed
972
	| ipvar '::' type		{ LL (HsIParamTy (unLoc $1) $3) }
waern's avatar
waern committed
973
	| type  			{ $1 }
974

975 976 977 978 979 980 981 982 983 984 985
----------------------
-- Notes for 'ctypedoc'
-- It would have been nice to simplify the grammar by unifying `ctype` and 
-- ctypedoc` into one production, allowing comments on types everywhere (and
-- rejecting them after parsing, where necessary).  This is however not possible
-- since it leads to ambiguity. The reason is the support for comments on record
-- fields: 
--         data R = R { field :: Int -- ^ comment on the field }
-- If we allow comments on types here, it's not clear if the comment applies
-- to 'field' or to 'Int'. So we must use `ctype` to describe the type.

986 987 988 989
ctypedoc :: { LHsType RdrName }
	: 'forall' tv_bndrs '.' ctypedoc	{ LL $ mkExplicitHsForAllTy $2 (noLoc []) $4 }
	| context '=>' ctypedoc		{ LL $ mkImplicitHsForAllTy   $1 $3 }
	-- A type of form (context => type) is an *implicit* HsForAllTy
batterseapower's avatar
batterseapower committed
990
	| ipvar '::' type		{ LL (HsIParamTy (unLoc $1) $3) }
waern's avatar
waern committed
991
	| typedoc			{ $1 }
992

993 994
----------------------
-- Notes for 'context'
995 996 997 998
-- 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 =>
999

waern's avatar
waern committed
1000
-- We have the t1 ~ t2 form both in 'context' and in type, 
1001 1002 1003
-- to permit an individual equational constraint without parenthesis.
-- Thus for some reason we allow    f :: a~b => blah
-- but not 	                    f :: ?x::Int => blah
1004
context :: { LHsContext RdrName }
1005
        : btype '~'      btype  	{% checkContext
batterseapower's avatar
batterseapower committed
1006
					     (LL $ HsEqTy $1 $3) }
1007
	| btype 			{% checkContext $1 }
1008

waern's avatar
waern committed
1009
type :: { LHsType RdrName }
1010
        : btype                         { $1 }
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
1011
        | btype qtyconop type           { LL $ HsOpTy $1 $2 $3 }
waern's avatar
waern committed
1012
        | btype tyvarop  type     	{ LL $ HsOpTy $1 $2 $3 }
1013
 	| btype '->'     ctype		{ LL $ HsFunTy $1 $3 }
batterseapower's avatar
batterseapower committed
1014
        | btype '~'      btype  	{ LL $ HsEqTy $1 $3 }
1015

waern's avatar
waern committed
1016
typedoc :: { LHsType RdrName }
1017 1018
        : btype                          { $1 }
        | btype docprev                  { LL $ HsDocTy $1 $2 }
waern's avatar
waern committed
1019 1020 1021 1022
        | btype qtyconop type            { LL $ HsOpTy $1 $2 $3 }
        | btype qtyconop type docprev    { LL $ HsDocTy (L (comb3 $1 $2 $3) (HsOpTy $1 $2 $3)) $4 }
        | btype tyvarop  type            { LL $ HsOpTy $1 $2 $3 }
        | btype tyvarop  type docprev    { LL $ HsDocTy (L (comb3 $1 $2 $3) (HsOpTy $1 $2 $3)) $4 }
1023 1024
        | btype '->'     ctypedoc        { LL $ HsFunTy $1 $3 }
        | btype docprev '->' ctypedoc    { LL $ HsFunTy (L (comb2 $1 $2) (HsDocTy $1 $2)) $4 }
batterseapower's avatar
batterseapower committed
1025
        | btype '~'      btype           { LL $ HsEqTy $1 $3 }
1026

1027 1028 1029 1030 1031 1032
btype :: { LHsType RdrName }
	: btype atype			{ LL $ HsAppTy $1 $2 }
	| atype				{ $1 }

atype :: { LHsType RdrName }
	: gtycon			{ L1 (HsTyVar (unLoc $1)) }
1033
	| tyvar				{ L1 (HsTyVar (unLoc $1)) }
1034
	| strict_mark atype		{ LL (HsBangTy (unLoc $1) $2) }  -- Constructor sigs only
1035
	| '{' fielddecls '}'		{% checkRecordSyntax (LL $ HsRecTy $2) } -- Constructor sigs only
batterseapower's avatar
batterseapower committed
1036 1037
	| '(' ctype ',' comma_types1 ')'  { LL $ HsTupleTy (HsBoxyTuple placeHolderKind)  ($2:$4) }
	| '(#' comma_types1 '#)'	{ LL $ HsTupleTy HsUnboxedTuple $2     }
1038 1039
	| '[' ctype ']'			{ LL $ HsListTy  $2 }
	| '[:' ctype ':]'		{ LL $ HsPArrTy  $2 }
1040
	| '(' ctype ')'		        { LL $ HsParTy   $2 }
1041
	| '(' ctype '::' kind ')'	{ LL $ HsKindSig $2 (unLoc $4) }
1042
	| quasiquote       	        { L1 (HsQuasiQuoteTy (unLoc $1)) }
1043 1044 1045
	| '$(' exp ')'	      		{ LL $ mkHsSpliceTy $2 }
	| TH_ID_SPLICE	      		{ LL $ mkHsSpliceTy $ L1 $ HsVar $ 
					  mkUnqual varName (getTH_ID_SPLICE $1) }
1046 1047 1048 1049 1050 1051

-- 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 }
1052
	: sigtype			{ $1 }
1053

1054 1055 1056 1057
inst_types1 :: { [LHsType RdrName] }
	: inst_type			{ [$1] }
	| inst_type ',' inst_types1	{ $1 : $3 }

1058 1059 1060 1061 1062
comma_types0  :: { [LHsType RdrName] }
	: comma_types1			{ $1 }
	| {- empty -}			{ [] }

comma_types1	:: { [LHsType RdrName] }
1063 1064
	: ctype				{ [$1] }
	| ctype  ',' comma_types1	{ $1 : $3 }
1065 1066 1067 1068 1069 1070

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

tv_bndr :: { LHsTyVarBndr RdrName }
1071
	: tyvar				{ L1 (UserTyVar (unLoc $1) placeHolderKind) }
1072 1073
	| '(' tyvar '::' kind ')'	{ LL (KindedTyVar (unLoc $2) 
							  (unLoc $4)) }
1074

1075
fds :: { Located [Located (FunDep RdrName)] }
1076 1077 1078
	: {- empty -}			{ noLoc [] }
	| '|' fds1			{ LL (reverse (unLoc $2)) }

1079
fds1 :: { Located [Located (FunDep RdrName)] }
1080 1081 1082
	: fds1 ',' fd			{ LL ($3 : unLoc $1) }
	| fd				{ L1 [$1] }

1083
fd :: { Located (FunDep RdrName) }
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093
	: 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

1094
kind	:: { Located Kind }
1095
	: akind			{ $1 }
1096
	| akind '->' kind	{ LL (mkArrowKind (unLoc $1) (unLoc $3)) }
1097

1098 1099 1100
akind	:: { Located Kind }
	: '*'			{ L1 liftedTypeKind }
	| '!'			{ L1 unliftedTypeKind }
batterseapower's avatar
batterseapower committed
1101
	| CONID         	{% checkKindName (L1 (getCONID $1)) }
1102
	| '(' kind ')'		{ LL (unLoc $2) }
1103 1104 1105 1106 1107


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

1108 1109 1110 1111
gadt_constrlist :: { Located [LConDecl RdrName] }	-- Returned in order
	: 'where' '{'        gadt_constrs '}'      { L (comb2 $1 $3) (unLoc $3) }
	| 'where' vocurly    gadt_constrs close	   { L (comb2 $1 $3) (unLoc $3) }
	| {- empty -}                              { noLoc [] }
1112 1113

gadt_constrs :: { Located [LConDecl RdrName] }
1114 1115 1116
        : gadt_constr ';' gadt_constrs  { L (comb2 (head $1) $3) ($1 ++ unLoc $3) }
        | gadt_constr                   { L (getLoc (head $1)) $1 }
        | {- empty -}	 		{ noLoc [] }
1117

1118 1119 1120 1121 1122 1123
-- 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

1124
gadt_constr :: { [LConDecl RdrName] }	-- Returns a list because of:   C,D :: ty
1125 1126
        : con_list '::' sigtype
                { map (sL (comb2 $1 $3)) (mkGadtDecl (unLoc $1) $3) } 
1127

1128 1129 1130
		-- Deprecated syntax for GADT record declarations
	| oqtycon '{' fielddecls '}' '::' sigtype
		{% do { cd <- mkDeprecatedGadtRecordDecl (comb2 $1 $6) $1 $3 $6
1131 1132
                      ; cd' <- checkRecordSyntax cd
                      ; return [cd'] } }
1133 1134

constrs :: { Located [LConDecl RdrName] }
1135
        : maybe_docnext '=' constrs1    { L (comb2 $2 $3) (addConDocs (unLoc $3) $1) }
1136 1137

constrs1 :: { Located [LConDecl RdrName] }
1138 1139
	: constrs1 maybe_docnext '|' maybe_docprev constr { LL (addConDoc $5 $2 : addConDocFirst (unLoc $1) $4) }
	| constr			                  { L1 [$1] }
1140 1141

constr :: { LConDecl RdrName }
1142 1143
	: maybe_docnext forall context '=>' constr_stuff maybe_docprev	
		{ let (con,details) = unLoc $5 in 
1144 1145
		  addConDoc (L (comb4 $2 $3 $4 $5) (mkSimpleConDecl con (unLoc $2) $3 details))
                            ($1 `mplus` $6) }
1146 1147
	| maybe_docnext forall constr_stuff maybe_docprev
		{ let (con,details) = unLoc $3 in 
1148 1149
		  addConDoc (L (comb2 $2 $3) (mkSimpleConDecl con (unLoc $2) (noLoc []) details))
                            ($1 `mplus` $4) }
1150 1151 1152 1153 1154

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

1155
constr_stuff :: { Located (Located RdrName, HsConDeclDetails RdrName) }
1156 1157 1158 1159 1160 1161 1162
-- 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)
1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178
	: btype				{% splitCon $1 >>= return.LL }
	| btype conop btype		{  LL ($2, InfixCon $1 $3) }

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

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

fielddecl :: { [ConDeclField RdrName] }    -- A list because of   f,g :: Int
	: maybe_docnext sig_vars '::' ctype maybe_docprev      { [ ConDeclField fld $4 ($1 `mplus` $5) 
                                                                 | fld <- reverse (unLoc $2) ] }
1179

1180 1181 1182 1183
-- 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.
1184 1185
deriving :: { Located (Maybe [LHsType RdrName]) }
	: {- empty -}				{ noLoc Nothing }
1186 1187
	| 'deriving' qtycon			{ let { L loc tv = $2 }
						  in LL (Just [L loc (HsTyVar tv)]) } 
1188 1189
	| 'deriving' '(' ')'	 		{ LL (Just []) }
	| 'deriving' '(' inst_types1 ')' 	{ LL (Just $3) }
1190 1191 1192 1193 1194 1195
             -- Glasgow extension: allow partial 
             -- applications in derivings

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

simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
1196 1197 1198
{- Note [Declaration/signature overlap]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
There's an awkward overlap with a type signature.  Consider