Macro validated_newtype::validated_newtype

macro_rules! validated_newtype {
    (
        $( #[$attr:meta] )*
        $parent:ty => $vis:vis $type:ident
        $(
            if $predicate:expr;
            else $error:expr => $error_type:ty
        )?
    ) => { ... };
    (
        $( #[$attr:meta] )*
        $parent:ty => $vis:vis $type:ident
        if $predicate:expr;
        error $message:literal
    ) => { ... };
}

Macro to create deserializable newtype with predicate validation. See crate docs for examples.