[project @ 2001-05-08 10:58:48 by simonmar]

[ghc-hetmet.git] / ghc / compiler / parser / Parser.y

diff --git a/ghc/compiler/parser/Parser.y b/ghc/compiler/parser/Parser.y
index 52d81e7..8894a00 100644 (file)
--- a/ghc/compiler/parser/Parser.y
+++ b/ghc/compiler/parser/Parser.y
@@ -1,6 +1,6 @@
 {-
 -----------------------------------------------------------------------------
-$Id: Parser.y,v 1.54 2001/02/20 15:36:55 simonpj Exp $
+$Id: Parser.y,v 1.60 2001/05/07 14:38:15 simonmar Exp $
 
 Haskell grammar.
 
@@ -9,7 +9,7 @@ Author(s): Simon Marlow, Sven Panne 1997, 1998, 1999
 -}
 
 {
-module Parser ( parseModule, parseExpr ) where
+module Parser ( parseModule, parseStmt ) where
 
 import HsSyn
 import HsTypes         ( mkHsTupCon )
@@ -200,7 +200,7 @@ Conflicts: 14 shift/reduce
 %monad { P } { thenP } { returnP }
 %lexer { lexer } { ITeof }
 %name parseModule module
-%name parseExpr   exp
+%name parseStmt   maybe_stmt
 %tokentype { Token }
 %%
 
@@ -328,7 +328,11 @@ topdecls :: { [RdrBinding] }
        | topdecl                       { [$1] }
 
 topdecl :: { RdrBinding }
-       : srcloc 'type' simpletype '=' sigtype  
+       : srcloc 'type' simpletype '=' ctype    
+               -- Note ctype, not sigtype.
+               -- 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
                { RdrHsDecl (TyClD (TySynonym (fst $3) (snd $3) $5 $1)) }
 
        | srcloc 'data' ctype '=' constrs deriving
@@ -382,8 +386,8 @@ decls       :: { [RdrBinding] }
 decl   :: { RdrBinding }
        : fixdecl                       { $1 }
        | valdef                        { $1 }
-       | '{-# INLINE'   srcloc opt_phase qvar '#-}'    { RdrSig (InlineSig $4 $3 $2) }
-       | '{-# NOINLINE' srcloc opt_phase qvar '#-}'    { RdrSig (NoInlineSig $4 $3 $2) }
+       | '{-# INLINE'   srcloc opt_phase qvar '#-}'     { RdrSig (InlineSig $4 $3 $2) }
+       | '{-# NOINLINE' srcloc opt_phase qvar '#-}'     { RdrSig (NoInlineSig $4 $3 $2) }
        | '{-# SPECIALISE' srcloc qvar '::' sigtypes '#-}'
                { foldr1 RdrAndBindings 
                    (map (\t -> RdrSig (SpecSig $3 t $2)) $5) }
@@ -424,7 +428,7 @@ rules       :: { RdrBinding }
        |  {- empty -}                          { RdrNullBind }
 
 rule   :: { RdrBinding }
-       : STRING rule_forall fexp '=' srcloc exp
+       : STRING rule_forall infixexp '=' srcloc exp
             { RdrHsDecl (RuleD (HsRule $1 [] $2 $3 $6 $5)) }
 
 rule_forall :: { [RdrNameRuleBndr] }
@@ -684,16 +688,16 @@ infixexp :: { RdrNameHsExpr }
                                                (panic "fixity") $3 )}
 
 exp10 :: { RdrNameHsExpr }
-       : '\\' aexp aexps opt_asig '->' srcloc exp      
-                       {% checkPatterns ($2 : reverse $3) `thenP` \ ps -> 
-                          returnP (HsLam (Match [] ps $4 
-                                           (GRHSs (unguardedRHS $7 $6) 
+       : '\\' srcloc aexp aexps opt_asig '->' srcloc exp       
+                       {% checkPatterns $2 ($3 : reverse $4) `thenP` \ ps -> 
+                          returnP (HsLam (Match [] ps $5 
+                                           (GRHSs (unguardedRHS $8 $7) 
                                                   EmptyBinds Nothing))) }
        | 'let' declbinds 'in' exp              { HsLet $2 $4 }
        | 'if' srcloc exp 'then' exp 'else' exp { HsIf $3 $5 $7 $2 }
        | 'case' srcloc exp 'of' altslist       { HsCase $3 $5 $2 }
        | '-' fexp                              { mkHsNegApp $2 }
-       | srcloc 'do' stmtlist                  { HsDo DoStmt $3 $1 }
+       | srcloc 'do' stmtlist                  { HsDo DoExpr $3 $1 }
 
        | '_ccall_'    ccallid aexps0           { HsCCall $2 $3 False False cbot }
        | '_ccall_GC_' ccallid aexps0           { HsCCall $2 $3 True  False cbot }
@@ -773,7 +777,7 @@ list :: { RdrNameHsExpr }
                                                 body  qss = [ParStmt (map reverse qss)] }
                                           in
                                           returnP ( HsDo ListComp
-                                                          (reverse (ReturnStmt $1 : body $3))
+                                                          (reverse (ExprStmt $1 $2 : body $3))
                                                           $2
                                                  )
                                        }
@@ -790,14 +794,8 @@ pquals :: { [[RdrNameStmt]] }
        | '|' quals                     { [$2] }
 
 quals :: { [RdrNameStmt] }
-       : quals ',' qual                { $3 : $1 }
-       | qual                          { [$1] }
-
-qual  :: { RdrNameStmt }
-       : srcloc infixexp '<-' exp      {% checkPattern $2 `thenP` \p ->
-                                          returnP (BindStmt p $4 $1) }
-       | srcloc exp                    { GuardStmt $2 $1 }
-       | srcloc 'let' declbinds        { LetStmt $3 }
+       : quals ',' stmt                { $3 : $1 }
+       | stmt                          { [$1] }
 
 -----------------------------------------------------------------------------
 -- Case alternatives
@@ -816,10 +814,10 @@ alts1     :: { [RdrNameMatch] }
        | alt                           { [$1] }
 
 alt    :: { RdrNameMatch }
-       : infixexp opt_sig ralt wherebinds
-                                       {% (checkPattern $1 `thenP` \p ->
-                                          returnP (Match [] [p] $2
-                                                    (GRHSs $3 $4 Nothing))  )}
+       : srcloc infixexp opt_sig ralt wherebinds
+                                       {% (checkPattern $1 $2 `thenP` \p ->
+                                          returnP (Match [] [p] $3
+                                                    (GRHSs $4 $5 Nothing))  )}
 
 ralt :: { [RdrNameGRHS] }
        : '->' srcloc exp               { [GRHS [ExprStmt $3 $2] $2] }
@@ -852,8 +850,14 @@ stmts1 :: { [RdrNameStmt] }
        | stmts1 ';'                    { $1 }
        | stmt                          { [$1] }
 
+-- for typing stmts at the GHCi prompt, where the input may consist of
+-- just comments.
+maybe_stmt :: { Maybe RdrNameStmt }
+       : stmt                          { Just $1 }
+       | {- nothing -}                 { Nothing }
+
 stmt  :: { RdrNameStmt }
-       : srcloc infixexp '<-' exp      {% checkPattern $2 `thenP` \p ->
+       : srcloc infixexp '<-' exp      {% checkPattern $1 $2 `thenP` \p ->
                                           returnP (BindStmt p $4 $1) }
        | srcloc exp                    { ExprStmt $2 $1 }
        | srcloc 'let' declbinds        { LetStmt $3 }