[Haskell-cafe] Optional EOF in Parsec.

I'm writing a parser with Parsec. In the input language, elements of a sequence are separated by commas: [1, 2, 3] However, instead of a comma, you can also use an EOL: [1, 2 3] Anywhere else, EOL is considered ignorable whitespace. So it's not as simple as just making EOL a token and looking for (comma | eol). I've implemented this functionality in a hand-written parser (basically a hack that keeps track of whether the last read token was preceded by an EOL, without making EOL itself a token). Does anybody have ideas about how to do this with Parsec?