macro_rules! named_unit_variant {
($variant:ident) => {
pub mod $variant {
pub fn serialize<S>(serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
serializer.serialize_str(stringify!($variant))
}
pub fn deserialize<'de, D>(deserializer: D) -> Result<(), D::Error>
where
D: serde::Deserializer<'de>,
{
struct V;
impl<'de> serde::de::Visitor<'de> for V {
type Value = ();
fn expecting(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
f.write_str(concat!("\"", stringify!($variant), "\""))
}
fn visit_str<E: serde::de::Error>(self, value: &str) -> Result<Self::Value, E> {
if value == stringify!($variant) {
Ok(())
} else {
Err(E::invalid_value(serde::de::Unexpected::Str(value), &self))
}
}
}
deserializer.deserialize_str(V)
}
}
};
}
named_unit_variant!(top);
named_unit_variant!(auto);