[Haskell-cafe] Re: [Parsec] No identEnd in ParsecToken?
bortzmeyer at nic.fr
Tue Sep 5 16:41:13 EDT 2006
On Tue, Sep 05, 2006 at 04:17:41PM +0200,
Stephane Bortzmeyer <bortzmeyer at nic.fr> wrote
a message of 25 lines which said:
> I'm trying to use Parsec for a language which have identifiers where
> the '-' character is allowed only inside identifiers, not at the
> start or the end.
[My grammar was underspecified, I also want to disallow two
Many thanks to Malcolm Wallace, Chris Kuklewicz and Udo Stenzel for
their help and ideas. It seems there is no solution for ParsecToken
(so I have to drop it). Among the two solutions which work for me
(Malcolm Wallace's and Udo Stenzel's), I choosed the one by Udo
because it is the one I understand the best.
Here is my final version (rewritten in my style, errors are mine and
not Udo's), thanks again:
import Text.ParserCombinators.Parsec hiding (spaces)
spaces = many1 (char ' ')
inner_minus = do
identifier = do
start <- letter
rest <- many (alphaNum <|> try inner_minus)
identifiers = do
result <- identifier `sepBy` spaces
main = do
parseTest identifiers "foo bar"
parseTest identifiers "foo-bar baz go-to"
parseTest identifiers "a b3 c56 e56-y7 gag-3456"
parseTest identifiers "1llegal"
parseTest identifiers "illegal- more"
parseTest identifiers "ill--egal more"
parseTest identifiers "illegal -more"
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