Macro fix_rs::define_enum_field_type

macro_rules! define_enum_field_type {
    (FIELD $enum_name:ident {
        $( $variant:ident => $value:expr, )+
    } $other_variant:tt,
    FIELD_TYPE [REQUIRED_AND_NOT_REQUIRED,BYTES] $required_field_type:ident $not_required_field_type:ident ) => { ... };
    (FIELD $enum_name:ident {
        $( $variant:ident => $value:expr, )+
    } $other_variant:tt => WITH_MINIMUM $minimum_value:expr,
    FIELD_TYPE [$required_sym:tt] $field_type:ident ) => { ... };
    (FIELD $enum_name:ident {
        $( $variant:ident => $value:expr, )+
    },
    FIELD_TYPE [REQUIRED_AND_NOT_REQUIRED,$must_be_sym:tt] $required_field_type:ident $not_required_field_type:ident ) => { ... };
    (FIELD $enum_name:ident {
        $( $variant:ident => $value:expr, )+
    },
    FIELD_TYPE [$required_sym:tt,$must_be_sym:tt] $field_type:ident ) => { ... };
}