Tired of writing complementary parseJSON/toJSON, peek/poke or Binary get/put functions?
codec provides easy bidirectional serialization of plain Haskell records in any Applicative context.
All you need to do is provide a de/serializer for every record field in any order you like,
and you get a de/serializer for the whole structure. The type system ensures that you provide
every record exactly once. It also includes a library for general record construction in an Applicative context,
of which creating codecs is just one application.
JSON! (full example)
data User = User
{ username :: Text
, userEmail :: Text
, userLanguages :: [ Text ]
, userReferrer :: Maybe User
} deriving Show
genFields ''User
userCodec :: JSONCodec User
userCodec = obj "user object" $
User
$>> f_username >-< "user"
>>> f_userEmail >-< "email"
>>> f_userLanguages >-< "languages"
>>> f_userReferrer >-< opt "referrer"
instance FromJSON User where
parseJSON = parseVal userCodec
instance ToJSON User where
toJSON = produceVal userCodec
Bit fields! (full example)
ipv4Codec :: BinaryCodec IPv4
ipv4Codec = toBytes $
IPv4
$>> f_version >-< word8 4
>>> f_ihl >-< word8 4
>>> f_dscp >-< word8 6
>>> f_ecn >-< word8 2
>>> f_totalLength >-< word16be 16
>>> f_identification >-< word16be 16
>>> f_flags >-< word8 3
>>> f_fragmentOffset >-< word16be 13
>>> f_timeToLive >-< word8 8
>>> f_protocol >-< word8 8
>>> f_headerChecksum >-< word16be 16
>>> f_sourceIP >-< word32be 32
>>> f_destIP >-< word32be 32
instance Binary IPv4 where
get = parse ipv4Codec
put = produce ipv4Codec
Storable! (full example)
timeSpecCodec :: ForeignCodec TimeSpec
timeSpecCodec =
TimeSpec
$>> f_seconds >-< field (#offset struct timespec, tv_sec) cInt
>>> f_nanoseconds >-< field (#offset struct timespec, tv_nsec) cInt
instance Storable TimeSpec where
peek = peekWith timeSpecCodec
poke = pokeWith timeSpecCodec
...
All of these examples use the same types and logic for constructing Codecs, and it's very easy to create Codecs for any parsing/serialization library.