Philippa Cowderoy
On Fri, 16 May 2008, Achim Schneider wrote:
My problem is that realTopLevel = expr, and that I get into an infinite recursion, never "closing" enough parens, never hitting eof.
Have you run into the left-recursion trap, by any chance?
This doesn't work:
expr = do expr; ...
expr = do {e <- parens expr; return $ Nest e} <|> lambda <|> _let <|> try app <|> atom There's at least one token before any recursion, so I guess not. After all, it terminates. It's my state that does not succeed in directing the parser not to mess up, so I'm reimplementing the thing as a two-pass but stateless parser now. Definitely the easier and clearer thing to do: I can have an end of line token that carries the number of trailing spaces, so I got perfect indent information without any pain involved, at all, and don't have to make parsers fail based on state. -- (c) this sig last receiving data processing entity. Inspect headers for past copyright information. All rights reserved. Unauthorised copying, hiring, renting, public performance and/or broadcasting of this signature prohibited.