diff options
| -rw-r--r-- | ghc/compiler/parser/Parser.y | 27 | ||||
| -rw-r--r-- | ghc/compiler/rename/RnExpr.lhs | 12 |
2 files changed, 27 insertions, 12 deletions
diff --git a/ghc/compiler/parser/Parser.y b/ghc/compiler/parser/Parser.y index 066bc1c150..0a44b9420d 100644 --- a/ghc/compiler/parser/Parser.y +++ b/ghc/compiler/parser/Parser.y @@ -1,6 +1,10 @@ {- ----------------------------------------------------------------------------- -$Id: Parser.y,v 1.12 1999/07/27 07:31:18 simonpj Exp $ +<<<<<<< Parser.y +$Id: Parser.y,v 1.13 1999/07/27 09:25:49 simonmar Exp $ +======= +$Id: Parser.y,v 1.13 1999/07/27 09:25:49 simonmar Exp $ +>>>>>>> 1.10 Haskell grammar. @@ -759,20 +763,21 @@ gdpat :: { RdrNameGRHS } -- Statement sequences stmtlist :: { [RdrNameStmt] } - : '{' stmts '}' { $2 } - | layout_on_for_do stmts close { $2 } + : '{' stmts '}' { reverse $2 } + | layout_on_for_do stmts close { reverse $2 } + +-- Stmt list should really end in an expression, but it's not +-- convenient to enforce this here, so we throw out erroneous +-- statement sequences in the renamer instead. --- Stmt list must end in an expression --- thought the H98 report doesn't currently say so in the syntax stmts :: { [RdrNameStmt] } - : stmts1 srcloc exp { reverse (ExprStmt $3 $2 : $1) } + : ';' stmts1 { $2 } + | stmts1 { $1 } --- A list of zero or more stmts, ending in semicolon --- Returned in *reverse* order stmts1 :: { [RdrNameStmt] } - : stmts1 stmt ';' { $2 : $1 } - | stmts1 ';' { $1 } - | { [] } + : stmts1 ';' stmt { $3 : $1 } + | stmts1 ';' { $1 } + | stmt { [$1] } stmt :: { RdrNameStmt } : srcloc infixexp '<-' exp {% checkPattern $2 `thenP` \p -> diff --git a/ghc/compiler/rename/RnExpr.lhs b/ghc/compiler/rename/RnExpr.lhs index ad4a408590..b9621e79fc 100644 --- a/ghc/compiler/rename/RnExpr.lhs +++ b/ghc/compiler/rename/RnExpr.lhs @@ -365,10 +365,16 @@ rnExpr (HsLet binds expr) rnExpr expr `thenRn` \ (expr',fvExpr) -> returnRn (HsLet binds' expr', fvExpr) -rnExpr (HsDo do_or_lc stmts src_loc) +rnExpr e@(HsDo do_or_lc stmts src_loc) = pushSrcLocRn src_loc $ lookupImplicitOccRn monadClass_RDR `thenRn` \ monad -> rnStmts rnExpr stmts `thenRn` \ (stmts', fvs) -> + -- check the statement list ends in an expression + case last stmts' of { + ExprStmt _ _ -> returnRn () ; + ReturnStmt _ -> returnRn () ; -- for list comprehensions + _ -> addErrRn (doStmtListErr e) + } `thenRn_` returnRn (HsDo do_or_lc stmts' src_loc, fvs `addOneFV` monad) rnExpr (ExplicitList exps) @@ -865,4 +871,8 @@ pp_op (op, fix) = hcat [quotes (ppr op), space, parens (ppr fix)] patSynErr e = sep [ptext SLIT("Pattern syntax in expression context:"), nest 4 (ppr e)] + +doStmtListErr e + = sep [ptext SLIT("`do' statements must end in expression:"), + nest 4 (ppr e)] \end{code} |