Parser.y.pp 67.5 KB
Newer Older
1 2 3 4 5 6 7 8 9 10
--								-*-haskell-*-
-- ---------------------------------------------------------------------------
-- (c) The University of Glasgow 1997-2003
---
-- The GHC grammar.
--
-- Author(s): Simon Marlow, Sven Panne 1997, 1998, 1999
-- ---------------------------------------------------------------------------

{
11
module Parser ( parseModule, parseStmt, parseIdentifier, parseType,
12
		parseHeader ) where
13 14 15 16 17 18

#define INCLUDE #include 
INCLUDE "HsVersions.h"

import HsSyn
import RdrHsSyn
19
import HscTypes		( IsBootInterface, DeprecTxt )
20 21 22 23 24
import Lexer
import RdrName
import TysWiredIn	( unitTyCon, unitDataCon, tupleTyCon, tupleCon, nilDataCon,
			  listTyCon_RDR, parrTyCon_RDR, consDataCon_RDR )
import Type		( funTyCon )
25
import ForeignCall	( Safety(..), CExportSpec(..), CLabelString,
26 27
			  CCallConv(..), CCallTarget(..), defaultCCallConv
			)
28
import OccName		( varName, dataName, tcClsName, tvName )
29 30
import DataCon		( DataCon, dataConName )
import SrcLoc		( Located(..), unLoc, getLoc, noLoc, combineSrcSpans,
31 32
			  SrcSpan, combineLocs, srcLocFile, 
			  mkSrcLoc, mkSrcSpan )
33
import Module
andy@galois.com's avatar
andy@galois.com committed
34
import StaticFlags	( opt_SccProfilingOn, opt_Hpc )
Simon Marlow's avatar
Simon Marlow committed
35
import Type		( Kind, mkArrowKind, liftedTypeKind, unliftedTypeKind )
36
import BasicTypes	( Boxity(..), Fixity(..), FixityDirection(..), IPName(..),
37
			  Activation(..), defaultInlineSpec )
38
import DynFlags
39
import OrdList
40 41 42
import HaddockParse
import {-# SOURCE #-} HaddockLex hiding ( Token )
import HaddockUtils
43 44 45 46

import FastString
import Maybes		( orElse )
import Outputable
47

48
import Control.Monad    ( unless )
Simon Marlow's avatar
Simon Marlow committed
49
import GHC.Exts
50 51
import Data.Char
import Control.Monad    ( mplus )
52 53 54
}

{-
55 56 57 58 59 60 61 62 63 64 65
-----------------------------------------------------------------------------
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

66 67 68 69 70 71 72 73 74 75 76
-----------------------------------------------------------------------------
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

77 78 79 80 81 82 83 84 85 86 87
-----------------------------------------------------------------------------
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

88 89 90 91 92 93 94 95 96 97 98
-----------------------------------------------------------------------------
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

99
-----------------------------------------------------------------------------
100
Conflicts: 38 shift/reduce (1.25)
101

102
10 for abiguity in 'if x then y else z + 1'		[State 178]
103 104 105
	(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

106
1 for ambiguity in 'if x then y else z :: T'		[State 178]
107 108
	(shift parses as 'if x then y else (z :: T)', as per longest-parse rule)

109
4 for ambiguity in 'if x then y else z -< e'		[State 178]
110
	(shift parses as 'if x then y else (z -< T)', as per longest-parse rule)
111 112 113 114 115 116 117 118 119 120
	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 ...
121

122
10 for ambiguity in 'e :: a `b` c'.  Does this mean 	[States 11, 253]
123 124
	(e::a) `b` c, or 
	(e :: (a `b` c))
125
    As well as `b` we can have !, VARSYM, QCONSYM, and CONSYM, hence 5 cases
126
    Same duplication between states 11 and 253 as the previous case
127

128
1 for ambiguity in 'let ?x ...'				[State 329]
129 130 131 132
	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.

133
1 for ambiguity in '{-# RULES "name" [ ... #-}		[State 382]
134 135 136 137
	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

138
1 for ambiguity in '{-# RULES "name" forall = ... #-}' 	[State 474]
139 140 141 142 143 144 145
	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'.

146 147 148 149
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.   

150 151 152 153 154 155 156 157 158 159 160
-- ---------------------------------------------------------------------------
-- 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
161
     -- This doesn't seem to work anymore -=chak
162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223

   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

224
 'forall'	{ L _ ITforall }		-- GHC extension keywords
225 226 227 228 229 230 231 232
 'foreign'	{ L _ ITforeign }
 'export'	{ L _ ITexport }
 'label'	{ L _ ITlabel } 
 'dynamic'	{ L _ ITdynamic }
 'safe'		{ L _ ITsafe }
 'threadsafe'	{ L _ ITthreadsafe }
 'unsafe'	{ L _ ITunsafe }
 'mdo'		{ L _ ITmdo }
233
 'family'	{ L _ ITfamily }
234 235 236 237 238 239
 'stdcall'      { L _ ITstdcallconv }
 'ccall'        { L _ ITccallconv }
 'dotnet'       { L _ ITdotnet }
 'proc'		{ L _ ITproc }		-- for arrow notation extension
 'rec'		{ L _ ITrec }		-- for arrow notation extension

240 241 242
 '{-# INLINE'      	  { L _ (ITinline_prag _) }
 '{-# SPECIALISE'  	  { L _ ITspec_prag }
 '{-# SPECIALISE_INLINE'  { L _ (ITspec_inline_prag _) }
243 244 245 246
 '{-# 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
247
 '{-# GENERATED'   { L _ ITgenerated_prag }
248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312
 '{-# 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    _) }
 PRIMFLOAT	{ L _ (ITprimfloat  _) }
 PRIMDOUBLE	{ L _ (ITprimdouble _) }
313 314 315 316 317 318 319

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

320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335
-- Template Haskell 
'[|'            { L _ ITopenExpQuote  }       
'[p|'           { L _ ITopenPatQuote  }      
'[t|'           { L _ ITopenTypQuote  }      
'[d|'           { L _ ITopenDecQuote  }      
'|]'            { L _ ITcloseQuote    }
TH_ID_SPLICE    { L _ (ITidEscape _)  }     -- $x
'$('	        { L _ ITparenEscape   }     -- $( exp )
TH_VAR_QUOTE	{ L _ ITvarQuote      }     -- 'x
TH_TY_QUOTE	{ L _ ITtyQuote       }      -- ''T

%monad { P } { >>= } { return }
%lexer { lexer } { L _ ITeof }
%name parseModule module
%name parseStmt   maybe_stmt
%name parseIdentifier  identifier
336
%name parseType ctype
337
%partial parseHeader header
338
%tokentype { (Located Token) }
339 340
%%

341 342 343 344 345 346 347 348
-----------------------------------------------------------------------------
-- Identifiers; one of the entry points
identifier :: { Located RdrName }
	: qvar				{ $1 }
	| qcon				{ $1 }
	| qvarop			{ $1 }
	| qconop			{ $1 }

349 350 351 352 353 354 355 356 357 358 359
-----------------------------------------------------------------------------
-- 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) }
360 361 362 363
 	: optdoc 'module' modid maybemoddeprec maybeexports 'where' body 
		{% fileSrcSpan >>= \ loc -> case $1 of { (opt, info, doc) -> 
		   return (L loc (HsModule (Just $3) $5 (fst $7) (snd $7) $4 
                          opt info doc) )}}
364
        | body2
365 366
		{% fileSrcSpan >>= \ loc ->
		   return (L loc (HsModule Nothing Nothing 
367
                          (fst $1) (snd $1) Nothing Nothing emptyHaddockModInfo 
368 369 370 371 372 373 374 375
                          Nothing)) }

optdoc :: { (Maybe String, HaddockModInfo RdrName, Maybe (HsDoc RdrName)) }                             
        : moduleheader            { (Nothing, fst $1, snd $1) }
        | docoptions              { (Just $1, emptyHaddockModInfo, Nothing)} 
        | docoptions moduleheader { (Just $1, fst $2, snd $2) } 
        | moduleheader docoptions { (Just $2, fst $1, snd $1) } 
        | {- empty -}             { (Nothing, emptyHaddockModInfo, Nothing) }  
376 377 378 379 380 381 382 383 384 385 386 387

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 }

388 389 390 391
body2 	:: { ([LImportDecl RdrName], [LHsDecl RdrName]) }
	:  '{' top '}'          		{ $2 }
 	|  missing_module_keyword top close     { $2 }

392 393 394 395 396 397 398 399
top 	:: { ([LImportDecl RdrName], [LHsDecl RdrName]) }
	: importdecls				{ (reverse $1,[]) }
	| importdecls ';' cvtopdecls		{ (reverse $1,$3) }
	| cvtopdecls				{ ([],$1) }

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

400 401 402 403
-----------------------------------------------------------------------------
-- Module declaration & imports only

header 	:: { Located (HsModule RdrName) }
404 405 406 407
 	: optdoc 'module' modid maybemoddeprec maybeexports 'where' header_body
		{% fileSrcSpan >>= \ loc -> case $1 of { (opt, info, doc) -> 
		   return (L loc (HsModule (Just $3) $5 $7 [] $4 
                   opt info doc))}}
408 409
	| missing_module_keyword importdecls
		{% fileSrcSpan >>= \ loc ->
410 411
		   return (L loc (HsModule Nothing Nothing $2 [] Nothing 
                   Nothing emptyHaddockModInfo Nothing)) }
412 413 414 415 416

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

417 418 419 420 421 422 423
-----------------------------------------------------------------------------
-- The Export List

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

424 425
exportlist :: { [LIE RdrName] }
	: expdoclist ',' expdoclist		{ $1 ++ $3 }
426 427 428
	| exportlist1				{ $1 }

exportlist1 :: { [LIE RdrName] }
429 430 431 432 433 434 435 436 437 438 439 440 441
        : 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)) }       
                       
442 443 444 445 446 447 448 449 450 451 452
   -- 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] }
453 454
	:  qcnames ',' qcname_ext	{ unLoc $3 : $1 }
	|  qcname_ext			{ [unLoc $1]  }
455

456 457 458 459 460 461 462 463
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.
464
qcname 	:: { Located RdrName }	-- Variable or data constructor
465 466
	:  qvar				{ $1 }
	|  qcon				{ $1 }
467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491

-----------------------------------------------------------------------------
-- 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
492
maybeas :: { Located (Maybe ModuleName) }
493 494 495 496 497 498 499 500
      	: '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]) }
501 502
	:  '(' exportlist ')'  			{ LL (False, $2) }
	|  'hiding' '(' exportlist ')' 		{ LL (True,  $3) }
503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522

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

523
topdecls :: { OrdList (LHsDecl RdrName) }
524 525 526
        : topdecls ';' topdecl		        { $1 `appOL` $3 }
        | topdecls ';'			        { $1 }
	| topdecl			        { $1 }
527

528
topdecl :: { OrdList (LHsDecl RdrName) }
529
  	: cl_decl			{ unitOL (L1 (TyClD (unLoc $1))) }
chak@cse.unsw.edu.au.'s avatar
chak@cse.unsw.edu.au. committed
530
  	| ty_decl			{ unitOL (L1 (TyClD (unLoc $1))) }
531 532 533 534
	| '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)))}
535
        | stand_alone_deriving                  { unitOL (LL (DerivD (unLoc $1))) }
536 537 538 539
	| 'default' '(' comma_types0 ')'	{ unitOL (LL $ DefD (DefaultDecl $3)) }
	| 'foreign' fdecl			{ unitOL (LL (unLoc $2)) }
	| '{-# DEPRECATED' deprecations '#-}'	{ $2 }
	| '{-# RULES' rules '#-}'		{ $2 }
540 541
      	| decl					{ unLoc $1 }

542 543 544 545 546 547
	-- Template Haskell Extension
	| '$(' exp ')'				{ unitOL (LL $ SpliceD (SpliceDecl $2)) }
	| TH_ID_SPLICE				{ unitOL (LL $ SpliceD (SpliceDecl $
							L1 $ HsVar (mkUnqual varName (getTH_ID_SPLICE $1))
						  )) }

548 549 550
-- Type classes
--
cl_decl :: { LTyClDecl RdrName }
551
	: 'class' tycl_hdr fds where_cls
552
		{% do { let { (binds, sigs, ats, docs)           = 
553
			        cvBindsAndSigs (unLoc $4)
554
		            ; (ctxt, tc, tvs, tparms) = unLoc $2}
555
                      ; checkTyVars tparms      -- only type vars allowed
556
		      ; checkKindSigs ats
557 558
		      ; return $ L (comb4 $1 $2 $3 $4) 
				   (mkClassDecl (ctxt, tc, tvs) 
559
					        (unLoc $3) sigs binds ats docs) } }
560

561
-- Type declarations (toplevel)
562 563
--
ty_decl :: { LTyClDecl RdrName }
564 565 566 567 568 569
           -- 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
570 571
	        --
		-- Note the use of type for the head; this allows
572 573 574
		-- infix type constructors to be declared 
 		{% do { (tc, tvs, _) <- checkSynHdr $2 False
		      ; return (L (comb2 $1 $4) 
575
				  (TySynonym tc tvs Nothing $4))
576 577 578
                      } }

           -- type family declarations
579
        | 'type' 'family' type opt_kind_sig 
580 581
		-- Note the use of type for the head; this allows
		-- infix type constructors to be declared
582
		--
583 584
 		{% do { (tc, tvs, _) <- checkSynHdr $3 False
		      ; return (L (comb3 $1 $3 $4) 
585
				  (TyFamily TypeFamily tc tvs (unLoc $4)))
586 587 588 589 590 591 592 593 594 595 596
		      } }

           -- 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)) 
                      } }
597

598
          -- ordinary data type or newtype declaration
599
	| data_or_newtype tycl_hdr constrs deriving
600
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $2}
601
                      ; checkTyVars tparms    -- no type pattern
602 603 604 605
		      ; return $
			  L (comb4 $1 $2 $3 $4)
			           -- We need the location on tycl_hdr in case 
				   -- constrs and deriving are both empty
606 607
			    (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) 
			       Nothing (reverse (unLoc $3)) (unLoc $4)) } }
608

609
          -- ordinary GADT declaration
610
        | data_or_newtype tycl_hdr opt_kind_sig 
611
		 'where' gadt_constrlist
612
		 deriving
613
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $2}
614
                      ; checkTyVars tparms    -- can have type pats
615 616
		      ; return $
			  L (comb4 $1 $2 $4 $5)
617 618
			    (mkTyData (unLoc $1) (ctxt, tc, tvs, Nothing) 
			      (unLoc $3) (reverse (unLoc $5)) (unLoc $6)) } }
619

620
          -- data/newtype family
621
        | 'data' 'family' tycl_hdr opt_kind_sig
622
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $3}
623 624 625 626
                      ; checkTyVars tparms            -- no type pattern
		      ; unless (null (unLoc ctxt)) $  -- and no context
			  parseError (getLoc ctxt) 
			    "A family declaration cannot have a context"
627
		      ; return $
628
			  L (comb3 $1 $2 $4)
629
			    (TyFamily DataFamily tc tvs (unLoc $4)) } }
630

631
          -- data/newtype instance declaration
632 633 634 635 636 637 638 639 640 641
	| 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)) } }

642
          -- GADT instance declaration
643 644 645 646 647 648 649 650
        | 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) 
651
			       (unLoc $4) (reverse (unLoc $6)) (unLoc $7)) } }
652

653 654 655 656 657 658 659 660
-- 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. 
661
--
662
at_decl_cls :: { LTyClDecl RdrName }
663
           -- type family declarations
664
        : 'type' type opt_kind_sig
665 666 667
		-- Note the use of type for the head; this allows
		-- infix type constructors to be declared
		--
668 669
 		{% do { (tc, tvs, _) <- checkSynHdr $2 False
		      ; return (L (comb3 $1 $2 $3) 
670
				  (TyFamily TypeFamily tc tvs (unLoc $3)))
671 672
		      } }

673
           -- default type instance
674
        | 'type' type '=' ctype
675 676 677
		-- Note the use of type for the head; this allows
		-- infix type constructors and type patterns
		--
678 679 680
 		{% do { (tc, tvs, typats) <- checkSynHdr $2 True
		      ; return (L (comb2 $1 $4) 
				  (TySynonym tc tvs (Just typats) $4)) 
681 682
                      } }

683
          -- data/newtype family declaration
684
        | 'data' tycl_hdr opt_kind_sig
685
		{% do { let {(ctxt, tc, tvs, tparms) = unLoc $2}
686 687 688 689
                      ; checkTyVars tparms            -- no type pattern
		      ; unless (null (unLoc ctxt)) $  -- and no context
			  parseError (getLoc ctxt) 
			    "A family declaration cannot have a context"
690
		      ; return $
691
			  L (comb3 $1 $2 $3)
692
			    (TyFamily DataFamily tc tvs (unLoc $3)) 
693
                      } }
694 695 696 697 698 699 700 701 702 703 704 705 706

-- 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)) 
                      } }
707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727

        -- 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) 
728
			     (unLoc $3) (reverse (unLoc $5)) (unLoc $6)) } }
729

730 731 732 733
data_or_newtype :: { Located NewOrData }
	: 'data'	{ L1 DataType }
	| 'newtype'	{ L1 NewType }

734 735 736
opt_kind_sig :: { Located (Maybe Kind) }
	: 				{ noLoc Nothing }
	| '::' kind			{ LL (Just (unLoc $2)) }
737

738
-- tycl_hdr parses the header of a class or data type decl,
739 740 741 742
-- which takes the form
--	T a b
-- 	Eq a => T a
--	(Eq a, Ord b) => T a b
743
--      T Int [a]			-- for associated types
744
-- Rather a lot of inlining here, else we get reduce/reduce errors
745 746 747
tycl_hdr :: { Located (LHsContext RdrName, 
		       Located RdrName, 
		       [LHsTyVarBndr RdrName],
748
		       [LHsType RdrName]) }
749
	: context '=>' type		{% checkTyClHdr $1         $3 >>= return.LL }
750 751
	| type				{% checkTyClHdr (noLoc []) $1 >>= return.L1 }

752 753 754 755 756
-----------------------------------------------------------------------------
-- Stand-alone deriving

-- Glasgow extension: stand-alone deriving declarations
stand_alone_deriving :: { LDerivDecl RdrName }
757
  	: 'deriving' 'instance' inst_type {% checkDerivDecl (LL (DerivDecl $3)) }
758

759 760 761
-----------------------------------------------------------------------------
-- Nested declarations

762
-- Declaration in class bodies
763
--
764 765 766 767 768 769 770 771 772
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 }
773 774


775
decllist_cls
776
        :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
777 778
	: '{'         decls_cls '}'	{ LL (unLoc $2) }
	|     vocurly decls_cls close	{ $2 }
779

780
-- Class body
781
--
782
where_cls :: { Located (OrdList (LHsDecl RdrName)) }	-- Reversed
783 784
				-- No implicit parameters
				-- May have type declarations
785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810
	: '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) }
811 812
	| {- empty -}			{ noLoc nilOL }

813 814
-- Declarations in binding groups other than classes and instances
--
815
decls 	:: { Located (OrdList (LHsDecl RdrName)) }	
816
	: decls ';' decl		{ LL (unLoc $1 `appOL` unLoc $3) }
817
	| decls ';'			{ LL (unLoc $1) }
818
	| decl				{ $1 }
819
	| {- empty -}			{ noLoc nilOL }
820

821
decllist :: { Located (OrdList (LHsDecl RdrName)) }
822 823 824
	: '{'            decls '}'	{ LL (unLoc $2) }
	|     vocurly    decls close	{ $2 }

825 826
-- Binding groups other than those of class and instance declarations
--
827
binds 	::  { Located (HsLocalBinds RdrName) } 		-- May have implicit parameters
828
						-- No type declarations
829 830 831
	: decllist			{ L1 (HsValBinds (cvBindGroup (unLoc $1))) }
	| '{'            dbinds '}'	{ LL (HsIPBinds (IPBinds (unLoc $2) emptyLHsBinds)) }
	|     vocurly    dbinds close	{ L (getLoc $2) (HsIPBinds (IPBinds (unLoc $2) emptyLHsBinds)) }
832

833
wherebinds :: { Located (HsLocalBinds RdrName) }	-- May have implicit parameters
834
						-- No type declarations
835
	: 'where' binds			{ LL (unLoc $2) }
836
	| {- empty -}			{ noLoc emptyLocalBinds }
837 838 839 840 841


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

842
rules	:: { OrdList (LHsDecl RdrName) }
843
	:  rules ';' rule			{ $1 `snocOL` $3 }
844
        |  rules ';'				{ $1 }
845 846
        |  rule					{ unitOL $1 }
	|  {- empty -}				{ nilOL }
847

848
rule  	:: { LHsDecl RdrName }
849
	: STRING activation rule_forall infixexp '=' exp
850 851
	     { LL $ RuleD (HsRule (getSTRING $1) 
				  ($2 `orElse` AlwaysActive) 
852
				  $3 $4 placeHolderNames $6 placeHolderNames) }
853

854 855 856
activation :: { Maybe Activation } 
        : {- empty -}                           { Nothing }
        | explicit_activation                   { Just $1 }
857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876

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)

877
deprecations :: { OrdList (LHsDecl RdrName) }
878
	: deprecations ';' deprecation		{ $1 `appOL` $3 }
879
	| deprecations ';' 			{ $1 }
880 881
	| deprecation				{ $1 }
	| {- empty -}				{ nilOL }
882 883

-- SUP: TEMPORARY HACK, not checking for `module Foo'
884
deprecation :: { OrdList (LHsDecl RdrName) }
885
	: depreclist STRING
886 887
		{ toOL [ LL $ DeprecD (Deprecation n (getSTRING $2)) 
		       | n <- unLoc $1 ] }
888 889 890 891 892 893


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

fdecl :: { LHsDecl RdrName }
Simon Marlow's avatar
Simon Marlow committed
894
fdecl : 'import' callconv safety fspec
895
		{% mkImport $2 $3 (unLoc $4) >>= return.LL }
Simon Marlow's avatar
Simon Marlow committed
896
      | 'import' callconv        fspec		
897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912
		{% 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) }
913 914
       : STRING var '::' sigtypedoc     { LL (L (getLoc $1) (getSTRING $1), $2, $4) }
       |        var '::' sigtypedoc     { LL (noLoc nilFS, $1, $3) }
915 916 917 918 919 920 921 922 923 924 925 926 927 928 929
         -- 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 }

930
sigtypes1 :: { [LHsType RdrName] }
931
	: sigtype			{ [ $1 ] }
932
	| sigtype ',' sigtypes1		{ $1 : $3 }
933 934 935 936 937

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

938 939 940 941
sigtypedoc :: { LHsType RdrName }
	: ctypedoc			{ L1 (mkImplicitHsForAllTy (noLoc []) $1) }
	-- Wrap an Implicit forall if there isn't one there already

942 943 944 945 946 947 948
sig_vars :: { Located [Located RdrName] }
	 : sig_vars ',' var		{ LL ($3 : unLoc $1) }
	 | var				{ L1 [$1] }

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

949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969
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 }
        | context '=>' gentypedoc        { LL $ mkImplicitHsForAllTy   $1 $3 }
	-- A type of form (context => type) is an *implicit* HsForAllTy
	| gentypedoc			 { $1 }
	
970 971 972 973
strict_mark :: { Located HsBang }
	: '!'				{ L1 HsStrict }
	| '{-# UNPACK' '#-}' '!'	{ LL HsUnbox }

974 975 976 977 978 979 980 981 982 983 984
-- 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 =>
985 986 987
--
-- We have the t1 ~ t2 form here and in gentype, to permit an individual
-- equational constraint without parenthesis.
988
context :: { LHsContext RdrName }
989 990 991
        : btype '~'      btype  	{% checkContext
					     (LL $ HsPredTy (HsEqualP $1 $3)) }
	| btype 			{% checkContext $1 }
992 993

type :: { LHsType RdrName }
994
	: ipvar '::' gentype		{ LL (HsPredTy (HsIParam (unLoc $1) $3)) }
995 996 997 998 999
	| gentype			{ $1 }

gentype :: { LHsType RdrName }
        : btype                         { $1 }
        | btype qtyconop gentype        { LL $ HsOpTy $1 $2 $3 }
1000
        | btype tyvarop  gentype  	{ LL $ HsOpTy $1 $2 $3 }
1001
 	| btype '->'     ctype		{ LL $ HsFunTy $1 $3 }
1002
        | btype '~'      btype  	{ LL $ HsPredTy (HsEqualP $1 $3) }
1003 1004 1005 1006 1007

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

1008 1009 1010 1011
btypedoc :: { LHsType RdrName }
	: btype atype docprev		{ LL $ HsDocTy (L (comb2 $1 $2) (HsAppTy $1 $2)) $3 }
        | atype docprev                 { LL $ HsDocTy $1 $2 }

1012 1013
atype :: { LHsType RdrName }
	: gtycon			{ L1 (HsTyVar (unLoc $1)) }
1014
	| tyvar				{ L1 (HsTyVar (unLoc $1)) }
1015
	| strict_mark atype		{ LL (HsBangTy (unLoc $1) $2) }
1016
	| '(' ctype ',' comma_types1 ')'  { LL $ HsTupleTy Boxed  ($2:$4) }
1017
	| '(#' comma_types1 '#)'	{ LL $ HsTupleTy Unboxed $2     }
1018 1019
	| '[' ctype ']'			{ LL $ HsListTy  $2 }
	| '[:' ctype ':]'		{ LL $ HsPArrTy  $2 }
1020
	| '(' ctype ')'		        { LL $ HsParTy   $2 }
1021
	| '(' ctype '::' kind ')'	{ LL $ HsKindSig $2 (unLoc $4) }
1022 1023 1024 1025 1026 1027 1028 1029
-- 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 }
1030
	: sigtype			{% checkInstType $1 }
1031

1032 1033 1034 1035
inst_types1 :: { [LHsType RdrName] }
	: inst_type			{ [$1] }
	| inst_type ',' inst_types1	{ $1 : $3 }

1036 1037 1038 1039 1040
comma_types0  :: { [LHsType RdrName] }
	: comma_types1			{ $1 }
	| {- empty -}			{ [] }

comma_types1	:: { [LHsType RdrName] }
1041 1042
	: ctype				{ [$1] }
	| ctype  ',' comma_types1	{ $1 : $3 }
1043 1044 1045 1046 1047 1048 1049

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

tv_bndr :: { LHsTyVarBndr RdrName }
	: tyvar				{ L1 (UserTyVar (unLoc $1)) }
1050 1051
	| '(' tyvar '::' kind ')'	{ LL (KindedTyVar (unLoc $2) 
							  (unLoc $4)) }
1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071

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

1072
kind	:: { Located Kind }
1073
	: akind			{ $1 }
1074
	| akind '->' kind	{ LL (mkArrowKind (unLoc $1) (unLoc $3)) }
1075

1076 1077 1078 1079
akind	:: { Located Kind }
	: '*'			{ L1 liftedTypeKind }
	| '!'			{ L1 unliftedTypeKind }
	| '(' kind ')'		{ LL (unLoc $2) }
1080 1081 1082 1083 1084


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

1085 1086 1087 1088 1089 1090
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) }
1091
        | gadt_constrs ';' 		{ $1 }
1092 1093
        | gadt_constr                   { L1 [$1] } 

1094 1095 1096 1097 1098 1099
-- 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

1100
gadt_constr :: { LConDecl RdrName }
1101
        : con '::' sigtype
1102 1103 1104
              { LL (mkGadtDecl $1 $3) } 
        -- Syntax: Maybe merge the record stuff with the single-case above?
        --         (to kill the mostly harmless reduce/reduce error)
1105
        -- XXX revisit audreyt
1106 1107
	| constr_stuff_record '::' sigtype
		{ let (con,details) = unLoc $1 in 
1108
		  LL (ConDecl con Implicit [] (noLoc []) details (ResTyGADT $3) Nothing) }
1109 1110 1111
{-
	| forall context '=>' constr_stuff_record '::' sigtype
		{ let (con,details) = unLoc $4 in 
1112
		  LL (ConDecl con Implicit (unLoc $1) $2 details (ResTyGADT $6) Nothing ) }
1113 1114
	| forall constr_stuff_record '::' sigtype
		{ let (con,details) = unLoc $2 in 
1115
		  LL (ConDecl con Implicit (unLoc $1) (noLoc []) details (ResTyGADT $4) Nothing) }
1116 1117
-}

1118 1119 1120

constrs :: { Located [LConDecl RdrName] }
        : {- empty; a GHC extension -}  { noLoc [] }
1121
        | maybe_docnext '=' constrs1    { L (comb2 $2 $3) (addConDocs (unLoc $3) $1) }
1122 1123

constrs1 :: { Located [LConDecl RdrName] }
1124 1125
	: constrs1 maybe_docnext '|' maybe_docprev constr { LL (addConDoc $5 $2 : addConDocFirst (unLoc $1) $4) }
	| constr			                  { L1 [$1] }
1126 1127

constr :: { LConDecl RdrName }
1128 1129 1130 1131 1132 1133
	: 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)) }
1134 1135 1136 1137 1138

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

1139
constr_stuff :: { Located (Located RdrName, HsConDeclDetails RdrName) }
1140 1141 1142 1143 1144 1145 1146
-- 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)
1147 1148 1149
	: btype				{% mkPrefixCon $1 [] >>= return.LL }
	| oqtycon '{' '}' 		{% mkRecCon $1 [] >>= return.LL }
	| oqtycon '{' fielddecls '}' 	{% mkRecCon $1 $3 >>= return.LL }
1150
	| btype conop btype		{ LL ($2, InfixCon $1 $3) }
1151

1152
constr_stuff_record :: { Located (Located RdrName, HsConDeclDetails RdrName) }
1153 1154 1155
	: oqtycon '{' '}' 		{% mkRecCon $1 [] >>= return.sL (comb2 $1 $>) }
	| oqtycon '{' fielddecls '}' 	{% mkRecCon $1 $3 >>= return.sL (comb2 $1 $>) }

1156 1157 1158
fielddecls :: { [([Located RdrName], LBangType RdrName, Maybe (LHsDoc RdrName))] }
	: fielddecl maybe_docnext ',' maybe_docprev fielddecls { addFieldDoc (unLoc $1) $4 : addFieldDocs $5 $2 }
	| fielddecl			                       { [unLoc $1] }
1159

1160 1161
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) }
1162

1163 1164 1165 1166
-- 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.
1167 1168
deriving :: { Located (Maybe [LHsType RdrName]) }
	: {- empty -}				{ noLoc Nothing }
1169 1170 1171
	| 'deriving' qtycon	{% do { let { L loc tv = $2 }
				      ; p <- checkInstType (L loc (HsTyVar tv))
				      ; return (LL (Just [p])) } }
1172 1173
	| 'deriving' '(' ')'	 		{ LL (Just []) }
	| 'deriving' '(' inst_types1 ')' 	{ LL (Just $3) }
1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199
             -- 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.
-}

1200 1201 1202 1203 1204 1205 1206 1207 1208
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) }

1209
decl 	:: { Located (OrdList (LHsDecl RdrName)) }
1210
	: sigdecl			{ $1 }
1211
	| '!' aexp rhs			{% do { pat <- checkPattern $2;
1212
					        return (LL $ unitOL $ LL $ ValD ( 
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
1213
							PatBind (LL $ BangPat pat) (unLoc $3)
1214
								placeHolderType placeHolderNames)) } }
1215
	| infixexp opt_sig rhs		{% do { r <- checkValDef $1 $2 $3;
1216
						return (LL $ unitOL (LL $ ValD r)) } }
1217
        | docdecl                       { LL $ unitOL $1 }
1218 1219

rhs	:: { Located (GRHSs RdrName) }
1220 1221
	: '=' exp wherebinds	{ L (comb3 $1 $2 $3) $ GRHSs (unguardedRHS $2) (unLoc $3) }
	| gdrhs	wherebinds	{ LL $ GRHSs (reverse (unLoc $1)) (unLoc $2) }
1222 1223 1224 1225 1226 1227

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

gdrh :: { LGRHS RdrName }
1228
	: '|' quals '=' exp  	{ sL (comb2 $1 $>) $ GRHS (reverse (unLoc $2)) $4 }
1229

1230
sigdecl :: { Located (OrdList (LHsDecl RdrName)) }
1231
	: infixexp '::' sigtypedoc
1232
				{% do s <- checkValSig $1 $3; 
1233
				      return (LL $ unitOL (LL $ SigD s)) }
1234
		-- See the above notes for why we need infixexp here
1235
	| var ',' sig_vars '::' sigtypedoc
1236
				{ LL $ toOL [ LL $ SigD (TypeSig n $5) | n <- $1 : unLoc $3 ] }
1237
	| infix prec ops	{ LL $ toOL [ LL $ SigD (FixSig (FixitySig n (Fixity $2 (unLoc $1))))
1238 1239
					     | n <- unLoc $3 ] }
	| '{-# INLINE'   activation qvar '#-}'	      
1240
				{ LL $ unitOL (LL $ SigD (InlineSig $3 (mkInlineSpec $2 (getINLINE $1)))) }
1241
	| '{-# SPECIALISE' qvar '::' sigtypes1 '#-}'
1242
			 	{ LL $ toOL [ LL $ SigD (SpecSig $2 t defaultInlineSpec) 
1243
					    | t <- $4] }
1244
	| '{-# SPECIALISE_INLINE' activation qvar '::' sigtypes1 '#-}'
1245
			 	{ LL $ toOL [ LL $ SigD (SpecSig $3 t (mkInlineSpec $2 (getSPEC_INLINE $1)))
1246
					    | t <- $5] }
1247
	| '{-# SPECIALISE' 'instance' inst_type '#-}'
1248
				{ LL $ unitOL (LL $ SigD (SpecInstSig $3)) }
1249 1250 1251 1252 1253 1254

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

exp   :: { LHsExpr RdrName }
	: infixexp '::' sigtype		{ LL $ ExprWithTySig $1 $3 }
1255 1256 1257 1258
	| 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}
1259 1260 1261 1262 1263 1264 1265
	| infixexp			{ $1 }

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

exp10 :: { LHsExpr RdrName }
1266 1267 1268 1269
	: '\\' apat apats opt_asig '->' exp	
			{ LL $ HsLam (mkMatchGroup [LL $ Match ($2:$3) $4
							   	(unguardedGRHSs $6)
							    ]) }
1270 1271
  	| 'let' binds 'in' exp			{ LL $ HsLet (unLoc $2) $4 }
	| 'if' exp 'then' exp 'else' exp	{ LL $ HsIf $2 $4 $6 }
1272
   	| 'case' exp 'of' altslist		{ LL $ HsCase $2 (mkMatchGroup (unLoc $4)) }
1273
	| '-' fexp				{ LL $ NegApp $2 noSyntaxExpr }
1274 1275

  	| 'do' stmtlist			{% let loc = comb2 $1 $2 in
1276 1277
					   checkDo loc (unLoc $2)  >>= \ (stmts,body) ->
					   return (L loc (mkHsDo DoExpr stmts body)) }
1278
  	| 'mdo' stmtlist		{% let loc = comb2 $1 $2 in
1279 1280
					   checkDo loc (unLoc $2)  >>= \ (stmts,body) ->
					   return (L loc (mkHsDo (MDoExpr noPostTcTable) stmts body)) }
1281 1282 1283
        | scc_annot exp		    		{ LL $ if opt_SccProfilingOn
							then HsSCC (unLoc $1) $2
							else HsPar $2 }
andy@galois.com's avatar
andy@galois.com committed
1284 1285 1286
        | hpc_annot exp		    		{ LL $ if opt_Hpc
							then HsTickPragma (unLoc $1) $2
							else HsPar $2 }
1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298

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

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

scc_annot :: { Located FastString }
1299 1300
	: '_scc_' STRING			{% (addWarning Opt_WarnDeprecations (getLoc $1) (text "_scc_ is deprecated; use an SCC pragma instead")) >>= \_ ->
                                   (return $ LL $ getSTRING $2) }
1301 1302
	| '{-# SCC' STRING '#-}'		{ LL $ getSTRING $2 }

andy@galois.com's avatar
andy@galois.com committed
1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314
hpc_annot :: { Located (FastString,(Int,Int),(Int,Int)) }
	: '{-# GENERATED' STRING INTEGER ':' INTEGER '-' INTEGER ':' INTEGER '#-}'
						{ LL $ (getSTRING $2
						       ,( fromInteger $ getINTEGER $3
 							, fromInteger $ getINTEGER $5
							)
                         			       ,( fromInteger $ getINTEGER $7
 							, fromInteger $ getINTEGER $9
							)
						       )
					         }

1315 1316 1317 1318 1319 1320 1321 1322 1323 1324
fexp 	:: { LHsExpr RdrName }
	: fexp aexp				{ LL $ HsApp $1 $2 }
  	| aexp					{ $1 }

aexp	:: { LHsExpr RdrName }
	: qvar '@' aexp			{ LL $ EAsPat $1 $3 }
	| '~' aexp			{ LL $ ELazyPat $2 }
	| aexp1				{ $1 }

aexp1	:: { LHsExpr RdrName }