I've also used Parsec for separated lexer + parser and currently have something like this to invoke them: testParse inputString = do case (parse myLexer "" inputString) of Left err -> fail ("lexical error: " ++ err) Right tokens -> case (parse myParser "" tokens) of Left err -> fail ("parse error: " ++ err) Right result -> return result ... or was this the "manual startup" that you were referring to? The above seems clunky to me, so I'd also welcome suggestions for piping the lexer output into the parser. What do you mean by "makes position calculations very complex"? Are you talking about reporting the position of lexical or parse errors? (If so, Parsec supports this quite well.) Alistair.
-----Original Message----- From: John Goerzen [mailto:jgoerzen@complete.org] Sent: 19 November 2004 14:28 To: haskell-cafe@haskell.org Subject: [Haskell-cafe] Parsec question
Hi,
I'm porting a parser over from an OCamllex/Ocamlyacc version and I'm using Parsec for both the tokenizer and the resulting token stream parser.
I have both of them working fine, but now my question is: how do I combine them? I can't quite figure out how to say "take the output from this GenParser Char () Tok and use it as the input for this GenParser Tok () ParserOutput".
Well, I have figured out an ugly way involving manually starting up both parsers, but it makes position calculations very complex. I suspect I'm missing something.
Ideas?
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