From: Ramakrishnan Muthukrishnan Date: Wed, 4 Feb 2015 11:30:23 +0000 (+0530) Subject: Add Strings, instance of the Show typeclass. X-Git-Url: https://git.rkrishnan.org/?a=commitdiff_plain;h=5b3b775acfb4d8b6e7f66395ef64b9edc61102f0;p=functorrent.git Add Strings, instance of the Show typeclass. --- diff --git a/src/Bencode.hs b/src/Bencode.hs index 0da372b..e1f6dd3 100644 --- a/src/Bencode.hs +++ b/src/Bencode.hs @@ -8,8 +8,6 @@ import Text.ParserCombinators.Parsec import Control.Applicative ((<*)) import Data.Functor - - data BVal = Bint Integer | Bstr BC.ByteString @@ -17,6 +15,11 @@ data BVal = | Bdict (M.Map BVal BVal) deriving (Ord, Eq) +instance Show BVal where + show (Bint i) = show i + show (Bstr s) = "\"" ++ BC.unpack s ++ "\"" + show (Blist xs) = show xs + show (Bdict m) = show (M.toList m) -- $setup -- >>> import Data.Either @@ -66,9 +69,21 @@ bencInt = do _ <- spaces parseNumber '-' (d'':_) | d'' == '0' = unexpected "numbers cannot be left-padded with zeros" parseNumber d'' ds'' = return (d'':ds'') -bencParser :: ParsecBS.Parser BVal -bencParser = Bstr <$> bencStr <|> - Bint <$> bencInt +-- | parse lists +-- +-- >>> parse bencList "Blist" (BC.pack "le") +-- Right [] +-- >>> parse bencList "Blist" (BC.pack "l4:spam4:eggse") +-- Right ["spam","eggs"] + +bencList :: ParsecBS.Parser [BVal] +bencList = do _ <- spaces + between (char 'l') (char 'e') (many bencVal) + +bencVal :: ParsecBS.Parser BVal +bencVal = Bstr <$> bencStr <|> + Bint <$> bencInt <|> + Blist <$> bencList decode :: BC.ByteString -> Either ParseError BVal -decode = parse bencParser "BVal" +decode = parse bencVal "BVal"