2 -----------------------------------------------------------------------------
3 $Id: Parser.y,v 1.52 2001/02/11 09:36:00 qrczak Exp $
7 Author(s): Simon Marlow, Sven Panne 1997, 1998, 1999
8 -----------------------------------------------------------------------------
12 module Parser ( parseModule, parseExpr ) where
15 import HsTypes ( mkHsTupCon )
22 import OccName ( UserFS, varName, ipName, tcName, dataName, tcClsName, tvName )
23 import SrcLoc ( SrcLoc )
26 import CmdLineOpts ( opt_SccProfilingOn )
27 import BasicTypes ( Boxity(..), Fixity(..), FixityDirection(..), NewOrData(..) )
31 import FastString ( tailFS )
34 #include "HsVersions.h"
38 -----------------------------------------------------------------------------
39 Conflicts: 14 shift/reduce
40 (note: it's currently 21 -- JRL, 31/1/2000)
42 8 for abiguity in 'if x then y else z + 1'
43 (shift parses as 'if x then y else (z + 1)', as per longest-parse rule)
44 1 for ambiguity in 'if x then y else z :: T'
45 (shift parses as 'if x then y else (z :: T)', as per longest-parse rule)
46 3 for ambiguity in 'case x of y :: a -> b'
47 (don't know whether to reduce 'a' as a btype or shift the '->'.
48 conclusion: bogus expression anyway, doesn't matter)
50 1 for ambiguity in '{-# RULES "name" forall = ... #-}'
51 since 'forall' is a valid variable name, we don't know whether
52 to treat a forall on the input as the beginning of a quantifier
53 or the beginning of the rule itself. Resolving to shift means
54 it's always treated as a quantifier, hence the above is disallowed.
55 This saves explicitly defining a grammar for the rule lhs that
56 doesn't include 'forall'.
58 1 for ambiguity in 'x @ Rec{..}'.
59 Only sensible parse is 'x @ (Rec{..})', which is what resolving
62 -----------------------------------------------------------------------------
66 '_' { ITunderscore } -- Haskell keywords
71 'default' { ITdefault }
72 'deriving' { ITderiving }
82 'instance' { ITinstance }
85 'newtype' { ITnewtype }
87 'qualified' { ITqualified }
91 '_scc_' { ITscc } -- ToDo: remove
93 'forall' { ITforall } -- GHC extension keywords
94 'foreign' { ITforeign }
97 'dynamic' { ITdynamic }
100 'stdcall' { ITstdcallconv }
101 'ccall' { ITccallconv }
102 '_ccall_' { ITccall (False, False, False) }
103 '_ccall_GC_' { ITccall (False, False, True) }
104 '_casm_' { ITccall (False, True, False) }
105 '_casm_GC_' { ITccall (False, True, True) }
107 '{-# SPECIALISE' { ITspecialise_prag }
108 '{-# SOURCE' { ITsource_prag }
109 '{-# INLINE' { ITinline_prag }
110 '{-# NOINLINE' { ITnoinline_prag }
111 '{-# RULES' { ITrules_prag }
112 '{-# SCC' { ITscc_prag }
113 '{-# DEPRECATED' { ITdeprecated_prag }
114 '#-}' { ITclose_prag }
117 '__interface' { ITinterface } -- interface keywords
118 '__export' { IT__export }
119 '__instimport' { ITinstimport }
120 '__forall' { IT__forall }
121 '__letrec' { ITletrec }
122 '__coerce' { ITcoerce }
123 '__depends' { ITdepends }
124 '__inline' { ITinline }
125 '__DEFAULT' { ITdefaultbranch }
127 '__integer' { ITinteger_lit }
128 '__float' { ITfloat_lit }
129 '__rational' { ITrational_lit }
130 '__addr' { ITaddr_lit }
131 '__label' { ITlabel_lit }
132 '__litlit' { ITlit_lit }
133 '__string' { ITstring_lit }
134 '__ccall' { ITccall $$ }
136 '__sccC' { ITsccAllCafs }
139 '__P' { ITspecialise }
141 '__U' { ITunfold $$ }
142 '__S' { ITstrict $$ }
143 '__M' { ITcprinfo $$ }
146 '..' { ITdotdot } -- reserved symbols
160 '{' { ITocurly } -- special symbols
164 vccurly { ITvccurly } -- virtual close curly (from layout)
175 VARID { ITvarid $$ } -- identifiers
177 VARSYM { ITvarsym $$ }
178 CONSYM { ITconsym $$ }
179 QVARID { ITqvarid $$ }
180 QCONID { ITqconid $$ }
181 QVARSYM { ITqvarsym $$ }
182 QCONSYM { ITqconsym $$ }
184 IPVARID { ITipvarid $$ } -- GHC extension
187 STRING { ITstring $$ }
188 INTEGER { ITinteger $$ }
189 RATIONAL { ITrational $$ }
191 PRIMCHAR { ITprimchar $$ }
192 PRIMSTRING { ITprimstring $$ }
193 PRIMINTEGER { ITprimint $$ }
194 PRIMFLOAT { ITprimfloat $$ }
195 PRIMDOUBLE { ITprimdouble $$ }
196 CLITLIT { ITlitlit $$ }
198 %monad { P } { thenP } { returnP }
199 %lexer { lexer } { ITeof }
200 %name parseModule module
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 (mkModuleNameFS $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 $1))) }
337 | srcloc 'newtype' ctype '=' newconstr deriving
338 {% checkDataHeader $3 `thenP` \(cs,c,ts) ->
339 returnP (RdrHsDecl (TyClD
340 (mkTyData NewType cs c ts [$5] 1 $6 $1))) }
342 | srcloc 'class' ctype fds where
343 {% checkDataHeader $3 `thenP` \(cs,c,ts) ->
345 (binds,sigs) = cvMonoBindsAndSigs cvClassOpSig (groupBindings $5)
347 returnP (RdrHsDecl (TyClD
348 (mkClassDecl cs c ts $4 sigs (Just binds) $1))) }
350 | srcloc 'instance' inst_type where
352 = cvMonoBindsAndSigs cvInstDeclSig
354 in RdrHsDecl (InstD (InstDecl $3 binds sigs Nothing $1)) }
356 | srcloc 'default' '(' types0 ')'
357 { RdrHsDecl (DefD (DefaultDecl $4 $1)) }
359 | srcloc 'foreign' 'import' callconv ext_name
360 unsafe_flag varid_no_unsafe '::' sigtype
361 { RdrHsDecl (ForD (ForeignDecl $7 (FoImport $6) $9 (mkExtName $5 $7) $4 $1)) }
363 | srcloc 'foreign' 'export' callconv ext_name varid '::' sigtype
364 { RdrHsDecl (ForD (ForeignDecl $6 FoExport $8 (mkExtName $5 $6) $4 $1)) }
366 | srcloc 'foreign' 'label' ext_name varid '::' sigtype
367 { RdrHsDecl (ForD (ForeignDecl $5 FoLabel $7 (mkExtName $4 $5)
368 defaultCallConv $1)) }
370 | '{-# DEPRECATED' deprecations '#-}' { $2 }
371 | '{-# RULES' rules '#-}' { $2 }
374 decls :: { [RdrBinding] }
375 : decls ';' decl { $3 : $1 }
380 decl :: { RdrBinding }
383 | '{-# INLINE' srcloc opt_phase qvar '#-}' { RdrSig (InlineSig $4 $3 $2) }
384 | '{-# NOINLINE' srcloc opt_phase qvar '#-}' { RdrSig (NoInlineSig $4 $3 $2) }
385 | '{-# SPECIALISE' srcloc qvar '::' sigtypes '#-}'
386 { foldr1 RdrAndBindings
387 (map (\t -> RdrSig (SpecSig $3 t $2)) $5) }
388 | '{-# SPECIALISE' srcloc 'instance' inst_type '#-}'
389 { RdrSig (SpecInstSig $4 $2) }
391 opt_phase :: { Maybe Int }
392 : INTEGER { Just (fromInteger $1) }
393 | {- empty -} { Nothing }
395 wherebinds :: { RdrNameHsBinds }
396 : where { cvBinds cvValSig (groupBindings $1) }
398 where :: { [RdrBinding] }
399 : 'where' decllist { $2 }
402 declbinds :: { RdrNameHsBinds }
403 : decllist { cvBinds cvValSig (groupBindings $1) }
405 decllist :: { [RdrBinding] }
406 : '{' decls '}' { $2 }
407 | layout_on decls close { $2 }
409 fixdecl :: { RdrBinding }
410 : srcloc infix prec ops { foldr1 RdrAndBindings
411 [ RdrSig (FixSig (FixitySig n
415 -----------------------------------------------------------------------------
416 -- Transformation Rules
418 rules :: { RdrBinding }
419 : rules ';' rule { $1 `RdrAndBindings` $3 }
422 | {- empty -} { RdrNullBind }
424 rule :: { RdrBinding }
425 : STRING rule_forall fexp '=' srcloc exp
426 { RdrHsDecl (RuleD (HsRule $1 [] $2 $3 $6 $5)) }
428 rule_forall :: { [RdrNameRuleBndr] }
429 : 'forall' rule_var_list '.' { $2 }
432 rule_var_list :: { [RdrNameRuleBndr] }
434 | rule_var rule_var_list { $1 : $2 }
436 rule_var :: { RdrNameRuleBndr }
437 : varid { RuleBndr $1 }
438 | '(' varid '::' ctype ')' { RuleBndrSig $2 $4 }
440 -----------------------------------------------------------------------------
443 deprecations :: { RdrBinding }
444 : deprecations ';' deprecation { $1 `RdrAndBindings` $3 }
445 | deprecations ';' { $1 }
447 | {- empty -} { RdrNullBind }
449 -- SUP: TEMPORARY HACK, not checking for `module Foo'
450 deprecation :: { RdrBinding }
451 : srcloc depreclist STRING
452 { foldr RdrAndBindings RdrNullBind
453 [ RdrHsDecl (DeprecD (Deprecation n $3 $1)) | n <- $2 ] }
455 -----------------------------------------------------------------------------
456 -- Foreign import/export
459 : 'stdcall' { stdCallConv }
460 | 'ccall' { cCallConv }
461 | {- empty -} { defaultCallConv }
463 unsafe_flag :: { Bool }
465 | {- empty -} { False }
467 ext_name :: { Maybe ExtName }
468 : 'dynamic' { Just Dynamic }
469 | STRING { Just (ExtName $1 Nothing) }
470 | STRING STRING { Just (ExtName $2 (Just $1)) }
471 | {- empty -} { Nothing }
474 -----------------------------------------------------------------------------
477 opt_sig :: { Maybe RdrNameHsType }
478 : {- empty -} { Nothing }
479 | '::' sigtype { Just $2 }
481 opt_asig :: { Maybe RdrNameHsType }
482 : {- empty -} { Nothing }
483 | '::' atype { Just $2 }
485 sigtypes :: { [RdrNameHsType] }
487 | sigtypes ',' sigtype { $3 : $1 }
489 sigtype :: { RdrNameHsType }
490 : ctype { (mkHsForAllTy Nothing [] $1) }
492 sig_vars :: { [RdrName] }
493 : sig_vars ',' var { $3 : $1 }
496 -----------------------------------------------------------------------------
499 -- A ctype is a for-all type
500 ctype :: { RdrNameHsType }
501 : 'forall' tyvars '.' ctype { mkHsForAllTy (Just $2) [] $4 }
502 | context type { mkHsForAllTy Nothing $1 $2 }
503 -- A type of form (context => type) is an *implicit* HsForAllTy
506 type :: { RdrNameHsType }
507 : gentype '->' type { HsFunTy $1 $3 }
508 | ipvar '::' type { mkHsIParamTy $1 $3 }
511 gentype :: { RdrNameHsType }
514 | atype tyconop atype { HsOpTy $1 $2 $3 }
516 btype :: { RdrNameHsType }
517 : btype atype { (HsAppTy $1 $2) }
520 atype :: { RdrNameHsType }
521 : gtycon { HsTyVar $1 }
522 | tyvar { HsTyVar $1 }
523 | '(' type ',' types ')' { HsTupleTy (mkHsTupCon tcName Boxed ($2:$4)) ($2 : reverse $4) }
524 | '(#' types '#)' { HsTupleTy (mkHsTupCon tcName Unboxed $2) (reverse $2) }
525 | '[' type ']' { HsListTy $2 }
526 | '(' ctype ')' { $2 }
528 | INTEGER { HsNumTy $1 }
530 -- An inst_type is what occurs in the head of an instance decl
531 -- e.g. (Foo a, Gaz b) => Wibble a b
532 -- It's kept as a single type, with a MonoDictTy at the right
533 -- hand corner, for convenience.
534 inst_type :: { RdrNameHsType }
535 : ctype {% checkInstType $1 }
537 types0 :: { [RdrNameHsType] }
538 : types { reverse $1 }
541 types :: { [RdrNameHsType] }
543 | types ',' type { $3 : $1 }
545 simpletype :: { (RdrName, [RdrNameHsTyVar]) }
546 : tycon tyvars { ($1, reverse $2) }
548 tyvars :: { [RdrNameHsTyVar] }
549 : tyvars tyvar { UserTyVar $2 : $1 }
552 fds :: { [([RdrName], [RdrName])] }
554 | '|' fds1 { reverse $2 }
556 fds1 :: { [([RdrName], [RdrName])] }
557 : fds1 ',' fd { $3 : $1 }
560 fd :: { ([RdrName], [RdrName]) }
561 : varids0 '->' varids0 { (reverse $1, reverse $3) }
563 varids0 :: { [RdrName] }
565 | varids0 tyvar { $2 : $1 }
567 -----------------------------------------------------------------------------
568 -- Datatype declarations
570 newconstr :: { RdrNameConDecl }
571 : srcloc conid atype { mkConDecl $2 [] [] (VanillaCon [Unbanged $3]) $1 }
572 | srcloc conid '{' var '::' type '}'
573 { mkConDecl $2 [] [] (RecCon [([$4], Unbanged $6)]) $1 }
575 constrs :: { [RdrNameConDecl] }
576 : constrs '|' constr { $3 : $1 }
579 constr :: { RdrNameConDecl }
580 : srcloc forall context constr_stuff
581 { mkConDecl (fst $4) $2 $3 (snd $4) $1 }
582 | srcloc forall constr_stuff
583 { mkConDecl (fst $3) $2 [] (snd $3) $1 }
585 forall :: { [RdrNameHsTyVar] }
586 : 'forall' tyvars '.' { $2 }
589 context :: { RdrNameContext }
590 : btype '=>' {% checkContext $1 }
592 constr_stuff :: { (RdrName, RdrNameConDetails) }
593 : btype {% mkVanillaCon $1 [] }
594 | btype '!' atype satypes {% mkVanillaCon $1 (Banged $3 : $4) }
595 | gtycon '{' fielddecls '}' {% mkRecCon $1 $3 }
596 | sbtype conop sbtype { ($2, InfixCon $1 $3) }
598 satypes :: { [RdrNameBangType] }
599 : atype satypes { Unbanged $1 : $2 }
600 | '!' atype satypes { Banged $2 : $3 }
603 sbtype :: { RdrNameBangType }
604 : btype { Unbanged $1 }
605 | '!' atype { Banged $2 }
607 fielddecls :: { [([RdrName],RdrNameBangType)] }
608 : fielddecl ',' fielddecls { $1 : $3 }
611 fielddecl :: { ([RdrName],RdrNameBangType) }
612 : sig_vars '::' stype { (reverse $1, $3) }
614 stype :: { RdrNameBangType }
615 : ctype { Unbanged $1 }
616 | '!' atype { Banged $2 }
618 deriving :: { Maybe [RdrName] }
619 : {- empty -} { Nothing }
620 | 'deriving' qtycls { Just [$2] }
621 | 'deriving' '(' ')' { Just [] }
622 | 'deriving' '(' dclasses ')' { Just (reverse $3) }
624 dclasses :: { [RdrName] }
625 : dclasses ',' qtycls { $3 : $1 }
628 -----------------------------------------------------------------------------
631 {- There's an awkward overlap with a type signature. Consider
632 f :: Int -> Int = ...rhs...
633 Then we can't tell whether it's a type signature or a value
634 definition with a result signature until we see the '='.
635 So we have to inline enough to postpone reductions until we know.
639 ATTENTION: Dirty Hackery Ahead! If the second alternative of vars is var
640 instead of qvar, we get another shift/reduce-conflict. Consider the
643 { (^^) :: Int->Int ; } Type signature; only var allowed
645 { (^^) :: Int->Int = ... ; } Value defn with result signature;
646 qvar allowed (because of instance decls)
648 We can't tell whether to reduce var to qvar until after we've read the signatures.
651 valdef :: { RdrBinding }
652 : infixexp srcloc opt_sig rhs {% (checkValDef $1 $3 $4 $2) }
653 | infixexp srcloc '::' sigtype {% (checkValSig $1 $4 $2) }
654 | var ',' sig_vars srcloc '::' sigtype { foldr1 RdrAndBindings
655 [ RdrSig (Sig n $6 $4) | n <- $1:$3 ]
659 rhs :: { RdrNameGRHSs }
660 : '=' srcloc exp wherebinds { (GRHSs (unguardedRHS $3 $2)
662 | gdrhs wherebinds { GRHSs (reverse $1) $2 Nothing }
664 gdrhs :: { [RdrNameGRHS] }
665 : gdrhs gdrh { $2 : $1 }
668 gdrh :: { RdrNameGRHS }
669 : '|' srcloc quals '=' exp { GRHS (reverse (ExprStmt $5 $2 : $3)) $2 }
671 -----------------------------------------------------------------------------
674 exp :: { RdrNameHsExpr }
675 : infixexp '::' sigtype { (ExprWithTySig $1 $3) }
676 | infixexp 'with' dbinding { HsWith $1 $3 }
679 infixexp :: { RdrNameHsExpr }
681 | infixexp qop exp10 { (OpApp $1 (HsVar $2)
682 (panic "fixity") $3 )}
684 exp10 :: { RdrNameHsExpr }
685 : '\\' aexp aexps opt_asig '->' srcloc exp
686 {% checkPatterns ($2 : reverse $3) `thenP` \ ps ->
687 returnP (HsLam (Match [] ps $4
688 (GRHSs (unguardedRHS $7 $6)
689 EmptyBinds Nothing))) }
690 | 'let' declbinds 'in' exp { HsLet $2 $4 }
691 | 'if' srcloc exp 'then' exp 'else' exp { HsIf $3 $5 $7 $2 }
692 | 'case' srcloc exp 'of' altslist { HsCase $3 $5 $2 }
693 | '-' fexp { mkHsNegApp $2 }
694 | srcloc 'do' stmtlist { HsDo DoStmt $3 $1 }
696 | '_ccall_' ccallid aexps0 { HsCCall $2 $3 False False cbot }
697 | '_ccall_GC_' ccallid aexps0 { HsCCall $2 $3 True False cbot }
698 | '_casm_' CLITLIT aexps0 { HsCCall $2 $3 False True cbot }
699 | '_casm_GC_' CLITLIT aexps0 { HsCCall $2 $3 True True cbot }
701 | scc_annot exp { if opt_SccProfilingOn
707 scc_annot :: { FAST_STRING }
708 : '_scc_' STRING { $2 }
709 | '{-# SCC' STRING '#-}' { $2 }
711 ccallid :: { FAST_STRING }
715 fexp :: { RdrNameHsExpr }
716 : fexp aexp { (HsApp $1 $2) }
719 aexps0 :: { [RdrNameHsExpr] }
720 : aexps { (reverse $1) }
722 aexps :: { [RdrNameHsExpr] }
723 : aexps aexp { $2 : $1 }
726 aexp :: { RdrNameHsExpr }
727 : var_or_con '{|' gentype '|}' { (HsApp $1 (HsType $3)) }
728 | aexp '{' fbinds '}' {% (mkRecConstrOrUpdate $1
732 var_or_con :: { RdrNameHsExpr }
736 aexp1 :: { RdrNameHsExpr }
737 : ipvar { HsIPVar $1 }
739 | literal { HsLit $1 }
740 | INTEGER { HsOverLit (HsIntegral $1 fromInteger_RDR) }
741 | RATIONAL { HsOverLit (HsFractional $1 fromRational_RDR) }
742 | '(' exp ')' { HsPar $2 }
743 | '(' exp ',' texps ')' { ExplicitTuple ($2 : reverse $4) Boxed}
744 | '(#' texps '#)' { ExplicitTuple (reverse $2) Unboxed }
745 | '[' list ']' { $2 }
746 | '(' infixexp qop ')' { (SectionL $2 (HsVar $3)) }
747 | '(' qopm infixexp ')' { (SectionR $2 $3) }
748 | qvar '@' aexp { EAsPat $1 $3 }
750 | '~' aexp1 { ELazyPat $2 }
752 texps :: { [RdrNameHsExpr] }
753 : texps ',' exp { $3 : $1 }
757 -----------------------------------------------------------------------------
760 -- The rules below are little bit contorted to keep lexps left-recursive while
761 -- avoiding another shift/reduce-conflict.
763 list :: { RdrNameHsExpr }
764 : exp { ExplicitList [$1] }
765 | lexps { ExplicitList (reverse $1) }
766 | exp '..' { ArithSeqIn (From $1) }
767 | exp ',' exp '..' { ArithSeqIn (FromThen $1 $3) }
768 | exp '..' exp { ArithSeqIn (FromTo $1 $3) }
769 | exp ',' exp '..' exp { ArithSeqIn (FromThenTo $1 $3 $5) }
770 | exp srcloc pquals {% let { body [qs] = qs;
771 body qss = [ParStmt (map reverse qss)] }
773 returnP ( HsDo ListComp
774 (reverse (ReturnStmt $1 : body $3))
779 lexps :: { [RdrNameHsExpr] }
780 : lexps ',' exp { $3 : $1 }
781 | exp ',' exp { [$3,$1] }
783 -----------------------------------------------------------------------------
784 -- List Comprehensions
786 pquals :: { [[RdrNameStmt]] }
787 : pquals '|' quals { $3 : $1 }
790 quals :: { [RdrNameStmt] }
791 : quals ',' qual { $3 : $1 }
794 qual :: { RdrNameStmt }
795 : srcloc infixexp '<-' exp {% checkPattern $2 `thenP` \p ->
796 returnP (BindStmt p $4 $1) }
797 | srcloc exp { GuardStmt $2 $1 }
798 | srcloc 'let' declbinds { LetStmt $3 }
800 -----------------------------------------------------------------------------
803 altslist :: { [RdrNameMatch] }
804 : '{' alts '}' { reverse $2 }
805 | layout_on alts close { reverse $2 }
807 alts :: { [RdrNameMatch] }
811 alts1 :: { [RdrNameMatch] }
812 : alts1 ';' alt { $3 : $1 }
816 alt :: { RdrNameMatch }
817 : infixexp opt_sig ralt wherebinds
818 {% (checkPattern $1 `thenP` \p ->
819 returnP (Match [] [p] $2
820 (GRHSs $3 $4 Nothing)) )}
822 ralt :: { [RdrNameGRHS] }
823 : '->' srcloc exp { [GRHS [ExprStmt $3 $2] $2] }
824 | gdpats { (reverse $1) }
826 gdpats :: { [RdrNameGRHS] }
827 : gdpats gdpat { $2 : $1 }
830 gdpat :: { RdrNameGRHS }
831 : srcloc '|' quals '->' exp { GRHS (reverse (ExprStmt $5 $1:$3)) $1}
833 -----------------------------------------------------------------------------
834 -- Statement sequences
836 stmtlist :: { [RdrNameStmt] }
837 : '{' stmts '}' { reverse $2 }
838 | layout_on_for_do stmts close { reverse $2 }
840 -- Stmt list should really end in an expression, but it's not
841 -- convenient to enforce this here, so we throw out erroneous
842 -- statement sequences in the renamer instead.
844 stmts :: { [RdrNameStmt] }
848 stmts1 :: { [RdrNameStmt] }
849 : stmts1 ';' stmt { $3 : $1 }
853 stmt :: { RdrNameStmt }
854 : srcloc infixexp '<-' exp {% checkPattern $2 `thenP` \p ->
855 returnP (BindStmt p $4 $1) }
856 | srcloc exp { ExprStmt $2 $1 }
857 | srcloc 'let' declbinds { LetStmt $3 }
859 -----------------------------------------------------------------------------
860 -- Record Field Update/Construction
862 fbinds :: { RdrNameHsRecordBinds }
863 : fbinds ',' fbind { $3 : $1 }
868 fbind :: { (RdrName, RdrNameHsExpr, Bool) }
869 : qvar '=' exp { ($1,$3,False) }
871 -----------------------------------------------------------------------------
872 -- Implicit Parameter Bindings
874 dbinding :: { [(RdrName, RdrNameHsExpr)] }
875 : '{' dbinds '}' { $2 }
876 | layout_on dbinds close { $2 }
878 dbinds :: { [(RdrName, RdrNameHsExpr)] }
879 : dbinds ';' dbind { $3 : $1 }
884 dbind :: { (RdrName, RdrNameHsExpr) }
885 dbind : ipvar '=' exp { ($1, $3) }
887 -----------------------------------------------------------------------------
888 -- Variables, Constructors and Operators.
890 depreclist :: { [RdrName] }
891 depreclist : deprec_var { [$1] }
892 | deprec_var ',' depreclist { $1 : $3 }
894 deprec_var :: { RdrName }
895 deprec_var : var { $1 }
898 gtycon :: { RdrName }
900 | '(' qtyconop ')' { $2 }
901 | '(' ')' { unitTyCon_RDR }
902 | '(' '->' ')' { funTyCon_RDR }
903 | '[' ']' { listTyCon_RDR }
904 | '(' commas ')' { tupleTyCon_RDR $2 }
907 : '(' ')' { unitCon_RDR }
908 | '[' ']' { nilCon_RDR }
909 | '(' commas ')' { tupleCon_RDR $2 }
914 | '(' varsym ')' { $2 }
918 | '(' varsym ')' { $2 }
919 | '(' qvarsym1 ')' { $2 }
920 -- We've inlined qvarsym here so that the decision about
921 -- whether it's a qvar or a var can be postponed until
922 -- *after* we see the close paren.
925 : IPVARID { (mkUnqual ipName (tailFS $1)) }
929 | '(' qconsym ')' { $2 }
933 | '`' varid '`' { $2 }
935 qvarop :: { RdrName }
937 | '`' qvarid '`' { $2 }
939 qvaropm :: { RdrName }
940 : qvarsym_no_minus { $1 }
941 | '`' qvarid '`' { $2 }
945 | '`' conid '`' { $2 }
947 qconop :: { RdrName }
949 | '`' qconid '`' { $2 }
951 -----------------------------------------------------------------------------
954 op :: { RdrName } -- used in infix decls
958 qop :: { RdrName {-HsExpr-} } -- used in sections
962 qopm :: { RdrNameHsExpr } -- used in sections
963 : qvaropm { HsVar $1 }
964 | qconop { HsVar $1 }
966 -----------------------------------------------------------------------------
969 qvarid :: { RdrName }
971 | QVARID { mkQual varName $1 }
974 : varid_no_unsafe { $1 }
975 | 'unsafe' { mkUnqual varName SLIT("unsafe") }
977 varid_no_unsafe :: { RdrName }
978 : VARID { mkUnqual varName $1 }
979 | special_id { mkUnqual varName $1 }
980 | 'forall' { mkUnqual varName SLIT("forall") }
983 : VARID { mkUnqual tvName $1 }
984 | special_id { mkUnqual tvName $1 }
985 | 'unsafe' { mkUnqual tvName SLIT("unsafe") }
987 -- These special_ids are treated as keywords in various places,
988 -- but as ordinary ids elsewhere. A special_id collects all thsee
989 -- except 'unsafe' and 'forall' whose treatment differs depending on context
990 special_id :: { UserFS }
992 : 'as' { SLIT("as") }
993 | 'qualified' { SLIT("qualified") }
994 | 'hiding' { SLIT("hiding") }
995 | 'export' { SLIT("export") }
996 | 'label' { SLIT("label") }
997 | 'dynamic' { SLIT("dynamic") }
998 | 'stdcall' { SLIT("stdcall") }
999 | 'ccall' { SLIT("ccall") }
1001 -----------------------------------------------------------------------------
1004 qconid :: { RdrName }
1006 | QCONID { mkQual dataName $1 }
1008 conid :: { RdrName }
1009 : CONID { mkUnqual dataName $1 }
1011 -----------------------------------------------------------------------------
1014 qconsym :: { RdrName }
1016 | QCONSYM { mkQual dataName $1 }
1018 consym :: { RdrName }
1019 : CONSYM { mkUnqual dataName $1 }
1021 -----------------------------------------------------------------------------
1024 qvarsym :: { RdrName }
1028 qvarsym_no_minus :: { RdrName }
1029 : varsym_no_minus { $1 }
1032 qvarsym1 :: { RdrName }
1033 qvarsym1 : QVARSYM { mkQual varName $1 }
1035 varsym :: { RdrName }
1036 : varsym_no_minus { $1 }
1037 | '-' { mkUnqual varName SLIT("-") }
1039 varsym_no_minus :: { RdrName } -- varsym not including '-'
1040 : VARSYM { mkUnqual varName $1 }
1041 | special_sym { mkUnqual varName $1 }
1044 -- See comments with special_id
1045 special_sym :: { UserFS }
1046 special_sym : '!' { SLIT("!") }
1049 -----------------------------------------------------------------------------
1052 literal :: { HsLit }
1053 : CHAR { HsChar $1 }
1054 | STRING { HsString $1 }
1055 | PRIMINTEGER { HsIntPrim $1 }
1056 | PRIMCHAR { HsCharPrim $1 }
1057 | PRIMSTRING { HsStringPrim $1 }
1058 | PRIMFLOAT { HsFloatPrim $1 }
1059 | PRIMDOUBLE { HsDoublePrim $1 }
1060 | CLITLIT { HsLitLit $1 (error "Parser.y: CLITLIT") }
1062 srcloc :: { SrcLoc } : {% getSrcLocP }
1064 -----------------------------------------------------------------------------
1068 : vccurly { () } -- context popped in lexer.
1069 | error {% popContext }
1071 layout_on :: { () } : {% layoutOn True{-strict-} }
1072 layout_on_for_do :: { () } : {% layoutOn False }
1074 -----------------------------------------------------------------------------
1075 -- Miscellaneous (mostly renamings)
1077 modid :: { ModuleName }
1078 : CONID { mkModuleNameFS $1 }
1080 tycon :: { RdrName }
1081 : CONID { mkUnqual tcClsName $1 }
1083 tyconop :: { RdrName }
1084 : CONSYM { mkUnqual tcClsName $1 }
1086 qtycon :: { RdrName }
1088 | QCONID { mkQual tcClsName $1 }
1090 qtyconop :: { RdrName }
1092 | QCONSYM { mkQual tcClsName $1 }
1094 qtycls :: { RdrName }
1098 : commas ',' { $1 + 1 }
1101 -----------------------------------------------------------------------------
1105 happyError buf PState{ loc = loc } = PFailed (srcParseErr buf loc)