2 -----------------------------------------------------------------------------
3 $Id: Parser.y,v 1.38 2000/10/05 15:42:30 simonpj Exp $
7 Author(s): Simon Marlow, Sven Panne 1997, 1998, 1999
8 -----------------------------------------------------------------------------
12 module Parser ( parse ) where
16 import HsTypes ( mkHsTupCon )
17 import HsPat ( InPat(..) )
23 import PrelInfo ( mAIN_Name )
24 import OccName ( UserFS, varName, ipName, tcName, dataName, tcClsName, tvName )
25 import SrcLoc ( SrcLoc )
28 import CmdLineOpts ( opt_SccProfilingOn )
29 import BasicTypes ( Boxity(..), Fixity(..), FixityDirection(..), NewOrData(..) )
33 import FastString ( tailFS )
36 #include "HsVersions.h"
40 -----------------------------------------------------------------------------
41 Conflicts: 14 shift/reduce
42 (note: it's currently 21 -- JRL, 31/1/2000)
44 8 for abiguity in 'if x then y else z + 1'
45 (shift parses as 'if x then y else (z + 1)', as per longest-parse rule)
46 1 for ambiguity in 'if x then y else z :: T'
47 (shift parses as 'if x then y else (z :: T)', as per longest-parse rule)
48 3 for ambiguity in 'case x of y :: a -> b'
49 (don't know whether to reduce 'a' as a btype or shift the '->'.
50 conclusion: bogus expression anyway, doesn't matter)
52 1 for ambiguity in '{-# RULES "name" forall = ... #-}'
53 since 'forall' is a valid variable name, we don't know whether
54 to treat a forall on the input as the beginning of a quantifier
55 or the beginning of the rule itself. Resolving to shift means
56 it's always treated as a quantifier, hence the above is disallowed.
57 This saves explicitly defining a grammar for the rule lhs that
58 doesn't include 'forall'.
60 1 for ambiguity in 'x @ Rec{..}'.
61 Only sensible parse is 'x @ (Rec{..})', which is what resolving
64 -----------------------------------------------------------------------------
68 '_' { ITunderscore } -- Haskell keywords
73 'default' { ITdefault }
74 'deriving' { ITderiving }
84 'instance' { ITinstance }
87 'newtype' { ITnewtype }
89 'qualified' { ITqualified }
95 'forall' { ITforall } -- GHC extension keywords
96 'foreign' { ITforeign }
99 'dynamic' { ITdynamic }
100 'unsafe' { ITunsafe }
102 'stdcall' { ITstdcallconv }
103 'ccall' { ITccallconv }
104 '_ccall_' { ITccall (False, False, False) }
105 '_ccall_GC_' { ITccall (False, False, True) }
106 '_casm_' { ITccall (False, True, False) }
107 '_casm_GC_' { ITccall (False, True, True) }
109 '{-# SPECIALISE' { ITspecialise_prag }
110 '{-# SOURCE' { ITsource_prag }
111 '{-# INLINE' { ITinline_prag }
112 '{-# NOINLINE' { ITnoinline_prag }
113 '{-# RULES' { ITrules_prag }
114 '{-# DEPRECATED' { ITdeprecated_prag }
115 '#-}' { ITclose_prag }
118 '__interface' { ITinterface } -- interface keywords
119 '__export' { IT__export }
120 '__instimport' { ITinstimport }
121 '__forall' { IT__forall }
122 '__letrec' { ITletrec }
123 '__coerce' { ITcoerce }
124 '__depends' { ITdepends }
125 '__inline' { ITinline }
126 '__DEFAULT' { ITdefaultbranch }
128 '__integer' { ITinteger_lit }
129 '__float' { ITfloat_lit }
130 '__rational' { ITrational_lit }
131 '__addr' { ITaddr_lit }
132 '__label' { ITlabel_lit }
133 '__litlit' { ITlit_lit }
134 '__string' { ITstring_lit }
135 '__ccall' { ITccall $$ }
137 '__sccC' { ITsccAllCafs }
140 '__P' { ITspecialise }
142 '__U' { ITunfold $$ }
143 '__S' { ITstrict $$ }
144 '__M' { ITcprinfo $$ }
147 '..' { ITdotdot } -- reserved symbols
161 '{' { ITocurly } -- special symbols
165 vccurly { ITvccurly } -- virtual close curly (from layout)
176 VARID { ITvarid $$ } -- identifiers
178 VARSYM { ITvarsym $$ }
179 CONSYM { ITconsym $$ }
180 QVARID { ITqvarid $$ }
181 QCONID { ITqconid $$ }
182 QVARSYM { ITqvarsym $$ }
183 QCONSYM { ITqconsym $$ }
185 IPVARID { ITipvarid $$ } -- GHC extension
188 STRING { ITstring $$ }
189 INTEGER { ITinteger $$ }
190 RATIONAL { ITrational $$ }
192 PRIMCHAR { ITprimchar $$ }
193 PRIMSTRING { ITprimstring $$ }
194 PRIMINTEGER { ITprimint $$ }
195 PRIMFLOAT { ITprimfloat $$ }
196 PRIMDOUBLE { ITprimdouble $$ }
197 CLITLIT { ITlitlit $$ }
199 %monad { P } { thenP } { returnP }
200 %lexer { lexer } { ITeof }
205 -----------------------------------------------------------------------------
208 -- The place for module deprecation is really too restrictive, but if it
209 -- was allowed at its natural place just before 'module', we get an ugly
210 -- s/r conflict with the second alternative. Another solution would be the
211 -- introduction of a new pragma DEPRECATED_MODULE, but this is not very nice,
212 -- either, and DEPRECATED is only expected to be used by people who really
213 -- know what they are doing. :-)
215 module :: { RdrNameHsModule }
216 : srcloc 'module' modid maybemoddeprec maybeexports 'where' body
217 { HsModule $3 Nothing $5 (fst $7) (snd $7) $4 $1 }
219 { HsModule mAIN_Name Nothing Nothing (fst $2) (snd $2) Nothing $1 }
221 maybemoddeprec :: { Maybe DeprecTxt }
222 : '{-# DEPRECATED' STRING '#-}' { Just $2 }
223 | {- empty -} { Nothing }
225 body :: { ([RdrNameImportDecl], [RdrNameHsDecl]) }
227 | layout_on top close { $2 }
229 top :: { ([RdrNameImportDecl], [RdrNameHsDecl]) }
230 : importdecls { (reverse $1,[]) }
231 | importdecls ';' cvtopdecls { (reverse $1,$3) }
232 | cvtopdecls { ([],$1) }
234 cvtopdecls :: { [RdrNameHsDecl] }
235 : topdecls { cvTopDecls (groupBindings $1)}
237 -----------------------------------------------------------------------------
240 maybeexports :: { Maybe [RdrNameIE] }
241 : '(' exportlist ')' { Just $2 }
242 | {- empty -} { Nothing }
244 exportlist :: { [RdrNameIE] }
245 : exportlist ',' export { $3 : $1 }
246 | exportlist ',' { $1 }
250 -- GHC extension: we allow things like [] and (,,,) to be exported
251 export :: { RdrNameIE }
253 | gtycon { IEThingAbs $1 }
254 | gtycon '(' '..' ')' { IEThingAll $1 }
255 | gtycon '(' ')' { IEThingWith $1 [] }
256 | gtycon '(' qcnames ')' { IEThingWith $1 (reverse $3) }
257 | 'module' modid { IEModuleContents $2 }
259 qcnames :: { [RdrName] }
260 : qcnames ',' qcname { $3 : $1 }
263 qcname :: { RdrName }
267 -----------------------------------------------------------------------------
268 -- Import Declarations
270 -- import decls can be *empty*, or even just a string of semicolons
271 -- whereas topdecls must contain at least one topdecl.
273 importdecls :: { [RdrNameImportDecl] }
274 : importdecls ';' importdecl { $3 : $1 }
275 | importdecls ';' { $1 }
276 | importdecl { [ $1 ] }
279 importdecl :: { RdrNameImportDecl }
280 : 'import' srcloc maybe_src optqualified CONID maybeas maybeimpspec
281 { ImportDecl (mkSrcModuleFS $5) $3 $4 $6 $7 $2 }
283 maybe_src :: { WhereFrom }
284 : '{-# SOURCE' '#-}' { ImportByUserSource }
285 | {- empty -} { ImportByUser }
287 optqualified :: { Bool }
288 : 'qualified' { True }
289 | {- empty -} { False }
291 maybeas :: { Maybe ModuleName }
292 : 'as' modid { Just $2 }
293 | {- empty -} { Nothing }
295 maybeimpspec :: { Maybe (Bool, [RdrNameIE]) }
296 : impspec { Just $1 }
297 | {- empty -} { Nothing }
299 impspec :: { (Bool, [RdrNameIE]) }
300 : '(' exportlist ')' { (False, reverse $2) }
301 | 'hiding' '(' exportlist ')' { (True, reverse $3) }
303 -----------------------------------------------------------------------------
304 -- Fixity Declarations
308 | INTEGER {% checkPrec $1 `thenP_`
309 returnP (fromInteger $1) }
311 infix :: { FixityDirection }
313 | 'infixl' { InfixL }
314 | 'infixr' { InfixR }
317 : ops ',' op { $3 : $1 }
320 -----------------------------------------------------------------------------
321 -- Top-Level Declarations
323 topdecls :: { [RdrBinding] }
324 : topdecls ';' topdecl { ($3 : $1) }
325 | topdecls ';' { $1 }
328 topdecl :: { RdrBinding }
329 : srcloc 'type' simpletype '=' sigtype
330 { RdrHsDecl (TyClD (TySynonym (fst $3) (snd $3) $5 $1)) }
332 | srcloc 'data' ctype '=' constrs deriving
333 {% checkDataHeader $3 `thenP` \(cs,c,ts) ->
334 returnP (RdrHsDecl (TyClD
335 (mkTyData DataType cs c ts (reverse $5) (length $5) $6
336 NoDataPragmas $1))) }
338 | srcloc 'newtype' ctype '=' newconstr deriving
339 {% checkDataHeader $3 `thenP` \(cs,c,ts) ->
340 returnP (RdrHsDecl (TyClD
341 (mkTyData NewType cs c ts [$5] 1 $6
342 NoDataPragmas $1))) }
344 | srcloc 'class' ctype fds where
345 {% checkDataHeader $3 `thenP` \(cs,c,ts) ->
347 (binds,sigs) = cvMonoBindsAndSigs cvClassOpSig (groupBindings $5)
349 returnP (RdrHsDecl (TyClD
350 (mkClassDecl cs c ts $4 sigs binds
351 NoClassPragmas $1))) }
353 | srcloc 'instance' inst_type where
355 = cvMonoBindsAndSigs cvInstDeclSig
357 in RdrHsDecl (InstD (InstDecl $3 binds sigs Nothing $1)) }
359 | srcloc 'default' '(' types0 ')'
360 { RdrHsDecl (DefD (DefaultDecl $4 $1)) }
362 | srcloc 'foreign' 'import' callconv ext_name
363 unsafe_flag varid_no_unsafe '::' sigtype
364 { RdrHsDecl (ForD (ForeignDecl $7 (FoImport $6) $9 (mkExtName $5 $7) $4 $1)) }
366 | srcloc 'foreign' 'export' callconv ext_name varid '::' sigtype
367 { RdrHsDecl (ForD (ForeignDecl $6 FoExport $8 (mkExtName $5 $6) $4 $1)) }
369 | srcloc 'foreign' 'label' ext_name varid '::' sigtype
370 { RdrHsDecl (ForD (ForeignDecl $5 FoLabel $7 (mkExtName $4 $5)
371 defaultCallConv $1)) }
373 | '{-# DEPRECATED' deprecations '#-}' { $2 }
374 | '{-# RULES' rules '#-}' { $2 }
377 decls :: { [RdrBinding] }
378 : decls ';' decl { $3 : $1 }
383 decl :: { RdrBinding }
386 | '{-# INLINE' srcloc opt_phase qvar '#-}' { RdrSig (InlineSig $4 $3 $2) }
387 | '{-# NOINLINE' srcloc opt_phase qvar '#-}' { RdrSig (NoInlineSig $4 $3 $2) }
388 | '{-# SPECIALISE' srcloc qvar '::' sigtypes '#-}'
389 { foldr1 RdrAndBindings
390 (map (\t -> RdrSig (SpecSig $3 t $2)) $5) }
391 | '{-# SPECIALISE' srcloc 'instance' inst_type '#-}'
392 { RdrSig (SpecInstSig $4 $2) }
394 opt_phase :: { Maybe Int }
395 : INTEGER { Just (fromInteger $1) }
396 | {- empty -} { Nothing }
398 wherebinds :: { RdrNameHsBinds }
399 : where { cvBinds cvValSig (groupBindings $1) }
401 where :: { [RdrBinding] }
402 : 'where' decllist { $2 }
405 declbinds :: { RdrNameHsBinds }
406 : decllist { cvBinds cvValSig (groupBindings $1) }
408 decllist :: { [RdrBinding] }
409 : '{' decls '}' { $2 }
410 | layout_on decls close { $2 }
412 fixdecl :: { RdrBinding }
413 : srcloc infix prec ops { foldr1 RdrAndBindings
414 [ RdrSig (FixSig (FixitySig n
418 -----------------------------------------------------------------------------
419 -- Transformation Rules
421 rules :: { RdrBinding }
422 : rules ';' rule { $1 `RdrAndBindings` $3 }
425 | {- empty -} { RdrNullBind }
427 rule :: { RdrBinding }
428 : STRING rule_forall fexp '=' srcloc exp
429 { RdrHsDecl (RuleD (HsRule $1 [] $2 $3 $6 $5)) }
431 rule_forall :: { [RdrNameRuleBndr] }
432 : 'forall' rule_var_list '.' { $2 }
435 rule_var_list :: { [RdrNameRuleBndr] }
437 | rule_var rule_var_list { $1 : $2 }
439 rule_var :: { RdrNameRuleBndr }
440 : varid { RuleBndr $1 }
441 | '(' varid '::' ctype ')' { RuleBndrSig $2 $4 }
443 -----------------------------------------------------------------------------
446 deprecations :: { RdrBinding }
447 : deprecations ';' deprecation { $1 `RdrAndBindings` $3 }
448 | deprecations ';' { $1 }
450 | {- empty -} { RdrNullBind }
452 -- SUP: TEMPORARY HACK, not checking for `module Foo'
453 deprecation :: { RdrBinding }
454 : srcloc exportlist STRING
455 { foldr RdrAndBindings RdrNullBind
456 [ RdrHsDecl (DeprecD (Deprecation n $3 $1)) | n <- $2 ] }
458 -----------------------------------------------------------------------------
459 -- Foreign import/export
462 : 'stdcall' { stdCallConv }
463 | 'ccall' { cCallConv }
464 | {- empty -} { defaultCallConv }
466 unsafe_flag :: { Bool }
468 | {- empty -} { False }
470 ext_name :: { Maybe ExtName }
471 : 'dynamic' { Just Dynamic }
472 | STRING { Just (ExtName $1 Nothing) }
473 | STRING STRING { Just (ExtName $2 (Just $1)) }
474 | {- empty -} { Nothing }
477 -----------------------------------------------------------------------------
480 opt_sig :: { Maybe RdrNameHsType }
481 : {- empty -} { Nothing }
482 | '::' sigtype { Just $2 }
484 opt_asig :: { Maybe RdrNameHsType }
485 : {- empty -} { Nothing }
486 | '::' atype { Just $2 }
488 sigtypes :: { [RdrNameHsType] }
490 | sigtypes ',' sigtype { $3 : $1 }
492 sigtype :: { RdrNameHsType }
493 : ctype { (mkHsForAllTy Nothing [] $1) }
495 sig_vars :: { [RdrName] }
496 : sig_vars ',' var { $3 : $1 }
499 -----------------------------------------------------------------------------
502 -- A ctype is a for-all type
503 ctype :: { RdrNameHsType }
504 : 'forall' tyvars '.' ctype { mkHsForAllTy (Just $2) [] $4 }
505 | context type { mkHsForAllTy Nothing $1 $2 }
506 -- A type of form (context => type) is an *implicit* HsForAllTy
509 type :: { RdrNameHsType }
510 : gentype '->' type { HsFunTy $1 $3 }
511 | ipvar '::' type { mkHsIParamTy $1 $3 }
514 gentype :: { RdrNameHsType }
517 | atype tyconop atype { HsOpTy $1 $2 $3 }
519 btype :: { RdrNameHsType }
520 : btype atype { (HsAppTy $1 $2) }
523 atype :: { RdrNameHsType }
524 : gtycon { HsTyVar $1 }
525 | tyvar { HsTyVar $1 }
526 | '(' type ',' types ')' { HsTupleTy (mkHsTupCon tcName Boxed ($2:$4)) ($2 : reverse $4) }
527 | '(#' types '#)' { HsTupleTy (mkHsTupCon tcName Unboxed $2) (reverse $2) }
528 | '[' type ']' { HsListTy $2 }
529 | '(' ctype ')' { $2 }
531 | INTEGER { HsNumTy $1 }
533 -- An inst_type is what occurs in the head of an instance decl
534 -- e.g. (Foo a, Gaz b) => Wibble a b
535 -- It's kept as a single type, with a MonoDictTy at the right
536 -- hand corner, for convenience.
537 inst_type :: { RdrNameHsType }
538 : ctype {% checkInstType $1 }
540 types0 :: { [RdrNameHsType] }
544 types :: { [RdrNameHsType] }
546 | types ',' type { $3 : $1 }
548 simpletype :: { (RdrName, [RdrNameHsTyVar]) }
549 : tycon tyvars { ($1, reverse $2) }
551 tyvars :: { [RdrNameHsTyVar] }
552 : tyvars tyvar { UserTyVar $2 : $1 }
555 fds :: { [([RdrName], [RdrName])] }
557 | '|' fds1 { reverse $2 }
559 fds1 :: { [([RdrName], [RdrName])] }
560 : fds1 ',' fd { $3 : $1 }
563 fd :: { ([RdrName], [RdrName]) }
564 : varids0 '->' varids0 { (reverse $1, reverse $3) }
566 varids0 :: { [RdrName] }
568 | varids0 tyvar { $2 : $1 }
570 -----------------------------------------------------------------------------
571 -- Datatype declarations
573 newconstr :: { RdrNameConDecl }
574 : srcloc conid atype { mkConDecl $2 [] [] (VanillaCon [Unbanged $3]) $1 }
575 | srcloc conid '{' var '::' type '}'
576 { mkConDecl $2 [] [] (RecCon [([$4], Unbanged $6)]) $1 }
578 constrs :: { [RdrNameConDecl] }
579 : constrs '|' constr { $3 : $1 }
582 constr :: { RdrNameConDecl }
583 : srcloc forall context constr_stuff
584 { mkConDecl (fst $4) $2 $3 (snd $4) $1 }
585 | srcloc forall constr_stuff
586 { mkConDecl (fst $3) $2 [] (snd $3) $1 }
588 forall :: { [RdrNameHsTyVar] }
589 : 'forall' tyvars '.' { $2 }
592 context :: { RdrNameContext }
593 : btype '=>' {% checkContext $1 }
595 constr_stuff :: { (RdrName, RdrNameConDetails) }
596 : btype {% mkVanillaCon $1 [] }
597 | btype '!' atype satypes {% mkVanillaCon $1 (Banged $3 : $4) }
598 | gtycon '{' fielddecls '}' {% mkRecCon $1 $3 }
599 | sbtype conop sbtype { ($2, InfixCon $1 $3) }
601 satypes :: { [RdrNameBangType] }
602 : atype satypes { Unbanged $1 : $2 }
603 | '!' atype satypes { Banged $2 : $3 }
605 sbtype :: { RdrNameBangType }
606 : btype { Unbanged $1 }
607 | '!' atype { Banged $2 }
609 fielddecls :: { [([RdrName],RdrNameBangType)] }
610 : fielddecls ',' fielddecl { $3 : $1 }
613 fielddecl :: { ([RdrName],RdrNameBangType) }
614 : sig_vars '::' stype { (reverse $1, $3) }
616 stype :: { RdrNameBangType }
617 : ctype { Unbanged $1 }
618 | '!' atype { Banged $2 }
620 deriving :: { Maybe [RdrName] }
621 : {- empty -} { Nothing }
622 | 'deriving' qtycls { Just [$2] }
623 | 'deriving' '(' ')' { Just [] }
624 | 'deriving' '(' dclasses ')' { Just (reverse $3) }
626 dclasses :: { [RdrName] }
627 : dclasses ',' qtycls { $3 : $1 }
630 -----------------------------------------------------------------------------
633 {- There's an awkward overlap with a type signature. Consider
634 f :: Int -> Int = ...rhs...
635 Then we can't tell whether it's a type signature or a value
636 definition with a result signature until we see the '='.
637 So we have to inline enough to postpone reductions until we know.
641 ATTENTION: Dirty Hackery Ahead! If the second alternative of vars is var
642 instead of qvar, we get another shift/reduce-conflict. Consider the
645 { (^^) :: Int->Int ; } Type signature; only var allowed
647 { (^^) :: Int->Int = ... ; } Value defn with result signature;
648 qvar allowed (because of instance decls)
650 We can't tell whether to reduce var to qvar until after we've read the signatures.
653 valdef :: { RdrBinding }
654 : infixexp srcloc opt_sig rhs {% (checkValDef $1 $3 $4 $2) }
655 | infixexp srcloc '::' sigtype {% (checkValSig $1 $4 $2) }
656 | var ',' sig_vars srcloc '::' sigtype { foldr1 RdrAndBindings
657 [ RdrSig (Sig n $6 $4) | n <- $1:$3 ]
661 rhs :: { RdrNameGRHSs }
662 : '=' srcloc exp wherebinds { (GRHSs (unguardedRHS $3 $2)
664 | gdrhs wherebinds { GRHSs (reverse $1) $2 Nothing }
666 gdrhs :: { [RdrNameGRHS] }
667 : gdrhs gdrh { $2 : $1 }
670 gdrh :: { RdrNameGRHS }
671 : '|' srcloc quals '=' exp { GRHS (reverse (ExprStmt $5 $2 : $3)) $2 }
673 -----------------------------------------------------------------------------
676 exp :: { RdrNameHsExpr }
677 : infixexp '::' sigtype { (ExprWithTySig $1 $3) }
678 | infixexp 'with' dbinding { HsWith $1 $3 }
681 infixexp :: { RdrNameHsExpr }
683 | infixexp qop exp10 { (OpApp $1 (HsVar $2)
684 (panic "fixity") $3 )}
686 exp10 :: { RdrNameHsExpr }
687 : '\\' aexp aexps opt_asig '->' srcloc exp
688 {% checkPatterns ($2 : reverse $3) `thenP` \ ps ->
689 returnP (HsLam (Match [] ps $4
690 (GRHSs (unguardedRHS $7 $6)
691 EmptyBinds Nothing))) }
692 | 'let' declbinds 'in' exp { HsLet $2 $4 }
693 | 'if' srcloc exp 'then' exp 'else' exp { HsIf $3 $5 $7 $2 }
694 | 'case' srcloc exp 'of' altslist { HsCase $3 $5 $2 }
695 | '-' fexp { mkHsNegApp $2 }
696 | srcloc 'do' stmtlist { HsDo DoStmt $3 $1 }
698 | '_ccall_' ccallid aexps0 { HsCCall $2 $3 False False cbot }
699 | '_ccall_GC_' ccallid aexps0 { HsCCall $2 $3 True False cbot }
700 | '_casm_' CLITLIT aexps0 { HsCCall $2 $3 False True cbot }
701 | '_casm_GC_' CLITLIT aexps0 { HsCCall $2 $3 True True cbot }
703 | '_scc_' STRING exp { if opt_SccProfilingOn
709 ccallid :: { FAST_STRING }
713 fexp :: { RdrNameHsExpr }
714 : fexp aexp { (HsApp $1 $2) }
717 aexps0 :: { [RdrNameHsExpr] }
718 : aexps { (reverse $1) }
720 aexps :: { [RdrNameHsExpr] }
721 : aexps aexp { $2 : $1 }
724 aexp :: { RdrNameHsExpr }
725 : var_or_con '{|' gentype '|}' { (HsApp $1 (HsType $3)) }
726 | aexp '{' fbinds '}' {% (mkRecConstrOrUpdate $1
730 var_or_con :: { RdrNameHsExpr }
734 aexp1 :: { RdrNameHsExpr }
735 : ipvar { HsIPVar $1 }
737 | literal { HsLit $1 }
738 | INTEGER { HsOverLit (mkHsIntegralLit $1) }
739 | RATIONAL { HsOverLit (mkHsFractionalLit $1) }
740 | '(' exp ')' { HsPar $2 }
741 | '(' exp ',' texps ')' { ExplicitTuple ($2 : reverse $4) Boxed}
742 | '(#' texps '#)' { ExplicitTuple (reverse $2) Unboxed }
743 | '[' list ']' { $2 }
744 | '(' infixexp qop ')' { (SectionL $2 (HsVar $3)) }
745 | '(' qopm infixexp ')' { (SectionR $2 $3) }
746 | qvar '@' aexp { EAsPat $1 $3 }
748 | '~' aexp1 { ELazyPat $2 }
750 texps :: { [RdrNameHsExpr] }
751 : texps ',' exp { $3 : $1 }
755 -----------------------------------------------------------------------------
758 -- The rules below are little bit contorted to keep lexps left-recursive while
759 -- avoiding another shift/reduce-conflict.
761 list :: { RdrNameHsExpr }
762 : exp { ExplicitList [$1] }
763 | lexps { ExplicitList (reverse $1) }
764 | exp '..' { ArithSeqIn (From $1) }
765 | exp ',' exp '..' { ArithSeqIn (FromThen $1 $3) }
766 | exp '..' exp { ArithSeqIn (FromTo $1 $3) }
767 | exp ',' exp '..' exp { ArithSeqIn (FromThenTo $1 $3 $5) }
768 | exp srcloc '|' quals { HsDo ListComp (reverse
769 (ReturnStmt $1 : $4)) $2 }
771 lexps :: { [RdrNameHsExpr] }
772 : lexps ',' exp { $3 : $1 }
773 | exp ',' exp { [$3,$1] }
775 -----------------------------------------------------------------------------
776 -- List Comprehensions
778 quals :: { [RdrNameStmt] }
779 : quals ',' qual { $3 : $1 }
782 qual :: { RdrNameStmt }
783 : srcloc infixexp '<-' exp {% checkPattern $2 `thenP` \p ->
784 returnP (BindStmt p $4 $1) }
785 | srcloc exp { GuardStmt $2 $1 }
786 | srcloc 'let' declbinds { LetStmt $3 }
788 -----------------------------------------------------------------------------
791 altslist :: { [RdrNameMatch] }
792 : '{' alts '}' { reverse $2 }
793 | layout_on alts close { reverse $2 }
795 alts :: { [RdrNameMatch] }
799 alts1 :: { [RdrNameMatch] }
800 : alts1 ';' alt { $3 : $1 }
804 alt :: { RdrNameMatch }
805 : infixexp opt_sig ralt wherebinds
806 {% (checkPattern $1 `thenP` \p ->
807 returnP (Match [] [p] $2
808 (GRHSs $3 $4 Nothing)) )}
810 ralt :: { [RdrNameGRHS] }
811 : '->' srcloc exp { [GRHS [ExprStmt $3 $2] $2] }
812 | gdpats { (reverse $1) }
814 gdpats :: { [RdrNameGRHS] }
815 : gdpats gdpat { $2 : $1 }
818 gdpat :: { RdrNameGRHS }
819 : srcloc '|' quals '->' exp { GRHS (reverse (ExprStmt $5 $1:$3)) $1}
821 -----------------------------------------------------------------------------
822 -- Statement sequences
824 stmtlist :: { [RdrNameStmt] }
825 : '{' stmts '}' { reverse $2 }
826 | layout_on_for_do stmts close { reverse $2 }
828 -- Stmt list should really end in an expression, but it's not
829 -- convenient to enforce this here, so we throw out erroneous
830 -- statement sequences in the renamer instead.
832 stmts :: { [RdrNameStmt] }
836 stmts1 :: { [RdrNameStmt] }
837 : stmts1 ';' stmt { $3 : $1 }
841 stmt :: { RdrNameStmt }
842 : srcloc infixexp '<-' exp {% checkPattern $2 `thenP` \p ->
843 returnP (BindStmt p $4 $1) }
844 | srcloc exp { ExprStmt $2 $1 }
845 | srcloc 'let' declbinds { LetStmt $3 }
847 -----------------------------------------------------------------------------
848 -- Record Field Update/Construction
850 fbinds :: { RdrNameHsRecordBinds }
851 : fbinds ',' fbind { $3 : $1 }
856 fbind :: { (RdrName, RdrNameHsExpr, Bool) }
857 : qvar '=' exp { ($1,$3,False) }
859 -----------------------------------------------------------------------------
860 -- Implicit Parameter Bindings
862 dbinding :: { [(RdrName, RdrNameHsExpr)] }
863 : '{' dbinds '}' { $2 }
864 | layout_on dbinds close { $2 }
866 dbinds :: { [(RdrName, RdrNameHsExpr)] }
867 : dbinds ';' dbind { $3 : $1 }
872 dbind :: { (RdrName, RdrNameHsExpr) }
873 dbind : ipvar '=' exp { ($1, $3) }
875 -----------------------------------------------------------------------------
876 -- Variables, Constructors and Operators.
878 gtycon :: { RdrName }
880 | '(' qtyconop ')' { $2 }
881 | '(' ')' { unitTyCon_RDR }
882 | '(' '->' ')' { funTyCon_RDR }
883 | '[' ']' { listTyCon_RDR }
884 | '(' commas ')' { tupleTyCon_RDR $2 }
887 : '(' ')' { unitCon_RDR }
888 | '[' ']' { nilCon_RDR }
889 | '(' commas ')' { tupleCon_RDR $2 }
894 | '(' varsym ')' { $2 }
898 | '(' varsym ')' { $2 }
899 | '(' qvarsym1 ')' { $2 }
900 -- We've inlined qvarsym here so that the decision about
901 -- whether it's a qvar or a var can be postponed until
902 -- *after* we see the close paren.
905 : IPVARID { (mkSrcUnqual ipName (tailFS $1)) }
909 | '(' qconsym ')' { $2 }
913 | '`' varid '`' { $2 }
915 qvarop :: { RdrName }
917 | '`' qvarid '`' { $2 }
919 qvaropm :: { RdrName }
920 : qvarsym_no_minus { $1 }
921 | '`' qvarid '`' { $2 }
925 | '`' conid '`' { $2 }
927 qconop :: { RdrName }
929 | '`' qconid '`' { $2 }
931 -----------------------------------------------------------------------------
934 op :: { RdrName } -- used in infix decls
938 qop :: { RdrName {-HsExpr-} } -- used in sections
942 qopm :: { RdrNameHsExpr } -- used in sections
943 : qvaropm { HsVar $1 }
944 | qconop { HsVar $1 }
946 -----------------------------------------------------------------------------
949 qvarid :: { RdrName }
951 | QVARID { mkSrcQual varName $1 }
954 : varid_no_unsafe { $1 }
955 | 'unsafe' { mkSrcUnqual varName SLIT("unsafe") }
957 varid_no_unsafe :: { RdrName }
958 : VARID { mkSrcUnqual varName $1 }
959 | special_id { mkSrcUnqual varName $1 }
960 | 'forall' { mkSrcUnqual varName SLIT("forall") }
963 : VARID { mkSrcUnqual tvName $1 }
964 | special_id { mkSrcUnqual tvName $1 }
965 | 'unsafe' { mkSrcUnqual tvName SLIT("unsafe") }
967 -- These special_ids are treated as keywords in various places,
968 -- but as ordinary ids elsewhere. A special_id collects all thsee
969 -- except 'unsafe' and 'forall' whose treatment differs depending on context
970 special_id :: { UserFS }
972 : 'as' { SLIT("as") }
973 | 'qualified' { SLIT("qualified") }
974 | 'hiding' { SLIT("hiding") }
975 | 'export' { SLIT("export") }
976 | 'label' { SLIT("label") }
977 | 'dynamic' { SLIT("dynamic") }
978 | 'stdcall' { SLIT("stdcall") }
979 | 'ccall' { SLIT("ccall") }
981 -----------------------------------------------------------------------------
984 qconid :: { RdrName }
986 | QCONID { mkSrcQual dataName $1 }
989 : CONID { mkSrcUnqual dataName $1 }
991 -----------------------------------------------------------------------------
994 qconsym :: { RdrName }
996 | QCONSYM { mkSrcQual dataName $1 }
998 consym :: { RdrName }
999 : CONSYM { mkSrcUnqual dataName $1 }
1001 -----------------------------------------------------------------------------
1004 qvarsym :: { RdrName }
1008 qvarsym_no_minus :: { RdrName }
1009 : varsym_no_minus { $1 }
1012 qvarsym1 :: { RdrName }
1013 qvarsym1 : QVARSYM { mkSrcQual varName $1 }
1015 varsym :: { RdrName }
1016 : varsym_no_minus { $1 }
1017 | '-' { mkSrcUnqual varName SLIT("-") }
1019 varsym_no_minus :: { RdrName } -- varsym not including '-'
1020 : VARSYM { mkSrcUnqual varName $1 }
1021 | special_sym { mkSrcUnqual varName $1 }
1024 -- See comments with special_id
1025 special_sym :: { UserFS }
1026 special_sym : '!' { SLIT("!") }
1029 -----------------------------------------------------------------------------
1032 literal :: { HsLit }
1033 : CHAR { HsChar $1 }
1034 | STRING { HsString $1 }
1035 | PRIMINTEGER { HsIntPrim $1 }
1036 | PRIMCHAR { HsCharPrim $1 }
1037 | PRIMSTRING { HsStringPrim $1 }
1038 | PRIMFLOAT { HsFloatPrim $1 }
1039 | PRIMDOUBLE { HsDoublePrim $1 }
1040 | CLITLIT { HsLitLit $1 (error "Parser.y: CLITLIT") }
1042 srcloc :: { SrcLoc } : {% getSrcLocP }
1044 -----------------------------------------------------------------------------
1048 : vccurly { () } -- context popped in lexer.
1049 | error {% popContext }
1051 layout_on :: { () } : {% layoutOn True{-strict-} }
1052 layout_on_for_do :: { () } : {% layoutOn False }
1054 -----------------------------------------------------------------------------
1055 -- Miscellaneous (mostly renamings)
1057 modid :: { ModuleName }
1058 : CONID { mkSrcModuleFS $1 }
1060 tycon :: { RdrName }
1061 : CONID { mkSrcUnqual tcClsName $1 }
1063 tyconop :: { RdrName }
1064 : CONSYM { mkSrcUnqual tcClsName $1 }
1066 qtycon :: { RdrName }
1068 | QCONID { mkSrcQual tcClsName $1 }
1070 qtyconop :: { RdrName }
1072 | QCONSYM { mkSrcQual tcClsName $1 }
1074 qtycls :: { RdrName }
1078 : commas ',' { $1 + 1 }
1081 -----------------------------------------------------------------------------
1085 happyError buf PState{ loc = loc } = PFailed (srcParseErr buf loc)