[project @ 2001-05-09 13:05:07 by simonpj]

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

diff --git a/ghc/compiler/parser/Parser.y b/ghc/compiler/parser/Parser.y
index b584fe8..ca4fafb 100644 (file)
--- a/ghc/compiler/parser/Parser.y
+++ b/ghc/compiler/parser/Parser.y
@@ -1,6 +1,6 @@
 {-
 -----------------------------------------------------------------------------
-$Id: Parser.y,v 1.62 2001/05/08 16:25:30 simonpj Exp $
+$Id: Parser.y,v 1.63 2001/05/09 13:05:07 simonpj Exp $
 
 Haskell grammar.
 
@@ -697,7 +697,8 @@ exp10 :: { RdrNameHsExpr }
        | '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 DoExpr $3 $1 }
+       | srcloc 'do' stmtlist                  {% checkDo $3  `thenP` \ stmts ->
+                                                  returnP (HsDo DoExpr stmts $1) }
 
        | '_ccall_'    ccallid aexps0           { HsCCall $2 $3 False False cbot }
        | '_ccall_GC_' ccallid aexps0           { HsCCall $2 $3 True  False cbot }
@@ -837,13 +838,22 @@ stmtlist :: { [RdrNameStmt] }
        : '{'                   stmts '}'       { $2 }
        |     layout_on_for_do  stmts close     { $2 }
 
+--     do { ;; s ; s ; ; s ;; }
+-- The last Stmt should be a ResultStmt, but that's hard to enforce
+-- here, because we need too much lookahead if we see do { e ; }
+-- So we use ExprStmts throughout, and switch the last one over
+-- in ParseUtils.checkDo instead
 stmts :: { [RdrNameStmt] }
+       : stmt stmts_help               { $1 : $2 }
+       | ';' stmts                     { $2 }
+       | {- empty -}                   { [] }
+
+stmts_help :: { [RdrNameStmt] }
        : ';' stmts                     { $2 }
-       | stmt ';' stmts                { $1 : $3 }
-       | srcloc exp                    { [ResultStmt $2 $1] }
+       | {- empty -}                   { [] }
 
--- for typing stmts at the GHCi prompt, where the input may consist of
--- just comments.
+-- For typing stmts at the GHCi prompt, where 
+-- the input may consist of just comments.
 maybe_stmt :: { Maybe RdrNameStmt }
        : stmt                          { Just $1 }
        | {- nothing -}                 { Nothing }