Data.TypedEncoding.Instances.Support.Helpers

Various helper functions. There are mostly for for creating ToEncString and FromEncString instances

Documentation

>>> :set -XTypeApplications
>>> import qualified Data.Text as T
>>> import           Data.Word

Composite encodings from Foldable Functor types

foldEnc :: forall (xs2 :: [Symbol]) (xs1 :: [Symbol]) f c s1 s2. (Foldable f, Functor f) => c -> (s1 -> s2 -> s2) -> s2 -> f (Enc xs1 c s1) -> Enc xs2 c s2

allows to fold payload in Enc to create another Enc, assumes homogeneous input encodings. This yields not a type safe code, better implementation code should use fixed size dependently typed Vect n or some HList like foldable.

Since: 0.2.0.0

foldCheckedEnc :: forall (xs2 :: [Symbol]) f c s1 s2. (Foldable f, Functor f) => c -> ([EncAnn] -> s1 -> s2 -> s2) -> s2 -> f (CheckedEnc c s1) -> Enc xs2 c s2

Similar to foldEnc, works with untyped CheckedEnc

Since: 0.2.0.0

Composite encoding: Recreate and Encode helpers

splitPayload :: forall (xs2 :: [Symbol]) (xs1 :: [Symbol]) c s1 s2. (s1 -> [s2]) -> Enc xs1 c s1 -> [Enc xs2 c s2]

Splits composite payload into homogeneous chunks

Since: 0.2.0.0

splitCheckedPayload :: forall c s1 s2. ([EncAnn] -> s1 -> [([EncAnn], s2)]) -> CheckedEnc c s1 -> [CheckedEnc c s2]

Untyped version of splitPayload

(renamed from splitCheckedPayload in previous versions) @since 0.5.0.0

Utility combinators

verifyWithRead :: forall a str. (IsStringR str, Read a, Show a) => String -> str -> Either String str

sometimes show . read is not identity, eg. Word8:

>>> read "256" :: Word8
0

>>> verifyWithRead @Word8 "Word8-decimal" (T.pack "256")
Left "Payload does not satisfy format Word8-decimal: 256"

>>> verifyWithRead @Word8 "Word8-decimal" (T.pack "123")
Right "123"

Since: 0.2.0.0

verifyDynEnc

Arguments

:: (KnownSymbol s, Show err1, Show err2)

=> Proxy s

proxy defining encoding annotation

-> (Proxy s -> Either err1 dec)

finds encoding marker dec for given annotation or fails

-> (dec -> str -> Either err2 a)

decoder based on dec marker

-> str

input

-> Either EncodeEx str

Convenience function for checking if str decodes without error using dec encoding markers and decoders that can pick decoder based on that marker

Since: 0.3.0.0