Macro scylla::impl_from_cql_value_from_method

macro_rules! impl_from_cql_value_from_method {
    ($T:ty, $convert_func:ident) => { ... };
}

This macro implements FromCqlVal given a type and method of CqlValue that returns this type.

It can be useful in client code in case you have an extension trait for CqlValue and you would like to convert one of its methods into a FromCqlVal impl. The conversion method must return an Option<T>. None values will be converted to CqlValue::BadCqlType.

Example

struct MyBytes(Vec<u8>);

trait CqlValueExt {
    fn into_my_bytes(self) -> Option<MyBytes>;
}

impl CqlValueExt for CqlValue {
    fn into_my_bytes(self) -> Option<MyBytes> {
        Some(MyBytes(self.into_blob()?))
    }
}

impl_from_cql_value_from_method!(MyBytes, into_my_bytes);