Starting example

with either removed

recreateFAll is the way to recover encoding in a safe way

>>> let payload = getPayload exAsciiT
>>> let newPayload = payload <> " some extra stuff"
>>> recreateFAll . toEncoding () $ newPayload :: Either RecreateEx (Enc '["r-ASCII"] () T.Text)
Right (MkEnc Proxy () "HELLO some extra stuff")

Alternatively, UncheckedEnc type can be used in recreation, see Overview

The issue with recreateFAll is that it may be expensive.

This apprach uses Unsafe to perform (in general risky) operation on the internal payload.

>>> exAsciiTE
Right (MkEnc Proxy () "HELLO")
>>> exAsciiTE >>= pure . Unsafe.withUnsafe (fmap T.toLower)
Right (MkEnc Proxy () "hello")

Example uses of toLower within encoded data this operation is safe for ASCII restriction but Enc '["r-ASCII"] () T.Text does not expose it We use Functor instance of Unsafe wrapper type to accomplish this

Similar example uses applicative instance of Unsafe

>>> let Right hELLO = exAsciiTE
>>> let Right hello = toLowerAscii
>>> displ $ Unsafe.runUnsafe ((<>) <$> Unsafe.Unsafe hELLO <*> Unsafe.Unsafe hello)
"MkEnc '[r-ASCII] () (Text HELLOhello)"