This declutters the main `xso` namespace. In addition, if (when) we
introduce more complex generic implementations, we might want to have
tests for these, and those can then live there, too, without making the
main `lib.rs` file gigantic (or moving the tests too far away from the
tested code).
This text codec was previously implemented only for Option<String>, this
extends it to all types implementing those two traits, such as numbers
or JIDs.
These more closely mirror how enums work currently with the macros.
Non-exhaustive enums may be useful though and kind of were the natural
thing to implement.
We can do this because we know that `x < y` cannot create a
`TextCodec<T>` for any `T`. This is because `<` is guaranteed to return
a boolean value, and we simply don't implement `TextCodec<T>` on bool.
This allows stateful or configurable codecs without having to express
all configuration in the type name itself. For example, we could have a
Base64 type with configurable Base64 engines without having to duplicate
the Base64 type itself.
(Note that the different engines in the Base64 crate are values, not
types.)
In 1265f4b, we introduced a change which may cause a conflict of type
names when deriving the traits on two different types. While a
workaround existed (use `mod`s to isolate the implementation), that is
ugly.
This commit allows overriding the choice of type names.
This introduces support for `Cow<'_, [u8]>` (which is not needed
currently, but still good to have) and generalizes the `Option<T>`
implementation so that it doesn't have to be copied for every other type
supported to be Base64'd (we may add support for `bytes::Bytes` at some
point, for instance).
Now it's not limited to a single feature gate per type (or even just
feature gates: it should now also be possible to add constraints
based on OS, for example) anymore.
This codec converts from a colon-separated case-insensitive hexadecimal
string into a Vec of bytes, and back to a lowercase colon-separated
hexadecimal string. Each byte must be separated by exactly one colon.
