[Haskell-cafe] Re: Parsec : Problems with operator precedence (solution)

Erik de Castro Lopo schrieb:

Erik de Castro Lopo wrote:

...

binaryOp :: String -> (SourcePos -> a -> a -> a) -> E.Assoc -> E.Operator Char st a binaryOp name con assoc = E.Infix (reservedOp name >> getPosition >>= return . con) assoc

Replacing reservedOp above with:

reservedOpNf :: String -> CharParser st () reservedOpNf name = try (reservedOp name >> notFollowedBy (oneOf "|&="))

fixed the problem.

Hi Erik, There is an easy, better solution, modifying the lexer:

lexer = makeTokenParser $ emptyDef { L.reservedOpNames = words "&& || & | ^" } reservedOp = P.reservedOp lexer identifier = P.identifier lexer ...

I'd try to avoid 'try', if possible. benedikt