I have a couple of questions about my first use of Parsec, which is trying to read morse code symbols from a string. I have a map of symbols: import qualified Data.Map as M morsemap = M.fromList [('A', ".-") ... , ('Z', "--..")] a string to parse, like test = "...---..-....-" and a Parser to read a single morse letter: morse1 :: GenParser Char st String morseletter = try $ M.fold ((<|>) . string) (string "") morsemap which I am hoping would be equivalent to try (string ".-") <|> (string "-.") ...etc <|> string "" but I don't know what the base of the fold should be (string "" is wrong I suppose) - what is the unit of <|>? Is there a readymade combinator for this? It fails anyway: *Main> run morse1 test parse error at (line 1, column 1): unexpected "." expecting ".-" I suppose this is because the strings I'm looking for overlap but I thought the use of try..<|> would avoid this error...? Thanks, -- View this message in context: http://www.nabble.com/Parsec-beginners-problem-tf3657821.html#a10219707 Sent from the Haskell - Haskell-Cafe mailing list archive at Nabble.com.