Data.TypedEncoding.Common.Class.Superset

Documentation

>>> :set -XOverloadedStrings -XMultiParamTypeClasses -XDataKinds -XTypeApplications
>>> import           Data.TypedEncoding
>>> import           Data.TypedEncoding.Instances.Restriction.UTF8 ()
>>> import           Data.TypedEncoding.Instances.Restriction.ASCII ()
>>> import           Data.Text as T

type family IsSuperset (y :: Symbol) (x :: Symbol) :: Bool where ...

Replaces previous Superset typeclass.

Subsets are useful for restriction encodings like r-UFT8 but should not be used for other encodings as this would be dangerous. For example, considering "enc-" encoding as a superset of "r-" encoding would permit converting encoded binary "Enc '["enc-"] c ByteString to "Enc '["r-ASCII"] c ByteString and then to "Enc '["r-ASCII"] c Text, which could result in runtime errors.

The requirement is that that the decoding in the superset can replace the decoding from injected subset.

IsSuperset bigger smaller reads as bigger is a superset of smaller

Since: 0.2.2.0

Equations

IsSuperset "r-ASCII" "r-ASCII" = True

IsSuperset "r-UTF8" "r-ASCII" = True

IsSuperset "r-UTF8" "r-UTF8" = True

IsSuperset y x = IsSupersetOpen y (TakeUntil x ":") (ToList x)

type family IsSupersetOpen (y :: Symbol) (x :: Symbol) (xs :: [Symbol]) :: Bool

Since: 0.2.2.0

Instances

type IsSupersetOpen "r-ASCII" "r-ban" xs

Defined in Data.TypedEncoding.Instances.Restriction.BoundedAlphaNums

type IsSupersetOpen "r-ASCII" "r-ban" xs = True

injectInto :: forall y x xs c str. IsSuperset y x ~ True => Enc (x ': xs) c str -> Enc (y ': xs) c str

>>> let Right tstAscii = encodeFAll . toEncoding () $ "Hello World" :: Either EncodeEx (Enc '["r-ASCII"] () T.Text)
>>> displ (injectInto @ "r-UTF8" tstAscii)
"Enc '[r-UTF8] () (Text Hello World)"

Since: 0.2.2.0

class EncodingSuperset (enc :: Symbol) where

IsSuperset is not intended for "enc-" encodings. This class is.

It allows to specify constraints that say, for example, that Base 64 encodes into a subset of ASCII.

Since: 0.3.0.0

Minimal complete definition

Nothing

Associated Types

type EncSuperset enc :: Symbol

Methods

implEncInto :: forall xs c str. Enc (enc ': xs) c str -> Enc (EncSuperset enc ': (enc ': xs)) c str

Warning: Using this method at the call site may not be backward compatible between minor version upgrades, use _encodesInto instead.

Instances

EncodingSuperset "enc-B64"

This is not precise, actually Base 64 uses a subset of ASCII and that would require a new definition "r-B64".

This instance likely to be changed / corrected in the future if "r-B64" is defined.

>>> let tstB64 = encodeAll . toEncoding () $ "Hello World" :: Enc '["enc-B64"] () B.ByteString
>>> displ (_encodesInto @"r-ASCII" $ tstB64)
"Enc '[r-ASCII,enc-B64] () (ByteString SGVsbG8gV29ybGQ=)"

>>> displ (_encodesInto @"r-UTF8" $ tstB64)
"Enc '[r-UTF8,enc-B64] () (ByteString SGVsbG8gV29ybGQ=)"

Since: 0.3.0.0

Defined in Data.TypedEncoding.Instances.Enc.Base64

Associated Types

type EncSuperset "enc-B64" :: Symbol

Methods

implEncInto :: Enc ("enc-B64" ': xs) c str -> Enc (EncSuperset "enc-B64" ': ("enc-B64" ': xs)) c str

_encodesInto :: forall y enc xs c str r. (IsSuperset y r ~ True, EncodingSuperset enc, r ~ EncSuperset enc) => Enc (enc ': xs) c str -> Enc (y ': (enc ': xs)) c str