Copyright	(c) 2015 Matthew Leon <ml@matthewleon.com>
License	BSD3
Maintainer	creichert07@gmail.com
Stability	experimental
Portability	portable
Safe Haskell	None
Language	Haskell2010
Extensions	GeneralizedNewtypeDeriving

Data.BEncode.Reader

Contents

Description

Reader monad and combinators for BEncoded data.

This is intended to replace the older Data.BEncode.Parser module.

Usage example:

>>> :set -XOverloadedStrings >>> let bd = (BDict $ Map.fromList [("baz", BInt 1), ("foo", BString "bar")]) >>> :{ let bReader = do baz <- dict "baz" bint foo <- dict "foo" bstring shouldBeNothing <- optional $ dict "optionalKey" bint return (foo, baz, shouldBeNothing) in runBReader bReader bd :} Right ("bar",1,Nothing)

Synopsis

dataBReader a
runBReader :: BReader a -> BEncode -> Either String a
bint :: BReader Integer
bbytestring :: BReader ByteString
bstring :: BReader String
optional :: Alternative f => f a -> f (Maybe a)
list :: BReader a -> BReader [a]
dict :: String -> BReader a -> BReader a

Reader Monad

dataBReader a Source #

Reader monad for extracting data from a BEncoded structure.

Instances

Monad BReaderSource #
Instance details Defined in Data.BEncode.Reader Methods (>>=) :: BReader a -> (a -> BReader b) -> BReader b # (>>) :: BReader a -> BReader b -> BReader b # return :: a -> BReader a # fail :: String -> BReader a #
Functor BReaderSource #
Instance details Defined in Data.BEncode.Reader Methods fmap :: (a -> b) -> BReader a -> BReader b # (<$) :: a -> BReader b -> BReader a #
Applicative BReaderSource #
Instance details Defined in Data.BEncode.Reader Methods pure :: a -> BReader a # (<>) :: BReader (a -> b) -> BReader a -> BReader b # liftA2 :: (a -> b -> c) -> BReader a -> BReader b -> BReader c # (>) :: BReader a -> BReader b -> BReader b # (<*) :: BReader a -> BReader b -> BReader a #
Alternative BReaderSource #
Instance details Defined in Data.BEncode.Reader Methods empty :: BReader a # (<\|>) :: BReader a -> BReader a -> BReader a # some :: BReader a -> BReader [a] # many :: BReader a -> BReader [a] #
MonadPlus BReaderSource #
Instance details Defined in Data.BEncode.Reader Methods mzero :: BReader a # mplus :: BReader a -> BReader a -> BReader a #

runBReader :: BReader a -> BEncode -> Either String a Source #

Run a BReader. See usage examples elsewhere in this file.

Combinators

bint :: BReader Integer Source #

>>> runBReader bint (BInt 42) Right 42

bbytestring :: BReader ByteString Source #

Usage same as bstring, below. (sadly, doctests for this cause errors on GHC 7.4)

bstring :: BReader String Source #

>>> runBReader bstring (BString "foo") Right "foo"

optional :: Alternative f => f a -> f (Maybe a) #

One or none.

list :: BReader a -> BReader [a] Source #

Read a list of BEncoded data

>>> runBReader (list bint) (BList [BInt 1, BInt 2]) Right [1,2]

>>> runBReader (list bint) (BList []) Right []

>>> let bs = (BList [BList [BString "foo", BString "bar"], BList []]) >>> runBReader (list $ list bstring) bs Right [["foo","bar"],[]]

dict :: String -> BReader a -> BReader a Source #

Read the values of a BDict corresponding to a string key

>>> let bd = (BDict $ Map.fromList [("bar", BInt 2), ("foo", BInt 1)]) >>> runBReader (dict "foo" bint) bd Right 1

>>> :{ let bs = (BList [BDict $ Map.fromList [("baz", BInt 2), ("foo", BString "bar")], BDict $ Map.singleton "foo" (BString "bam")]) in runBReader (list $ dict "foo" bstring) bs :} Right ["bar","bam"]

>>> :{ let bd = (BDict $ Map.singleton "foo" (BList [ BString "foo", BString "bar" ])) in runBReader (dict "foo" $ list $ bstring) bd :} Right ["foo","bar"]