Data.TypedEncoding.Instances.Support.Helpers

Support for mostly creating instances ToEncString and FromEncString conversions

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.

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

Similar to foldEnc, assumes that destination payload has IsString instance and uses "" as base case.

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

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

Similar to foldEncStr, works with untyped CheckedEnc

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 homogenious chunks

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

Untyped version of splitPayload

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"

verifyDynEnc

Arguments

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

=> Proxy s

proxy defining encoding annotation

-> (Proxy s -> Either err1 enc)

finds encoding marker enc for given annotation or fails

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

decoder based on enc marker

-> str

input

-> Either EncodeEx str

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