Macro filter_field_set 

macro_rules! filter_field_set {
    ($selector:expr, { 
        $(
            $($field_part:tt).+ => $($output:expr);+
        ),* $(,)?
    }) => { ... };
}

Create a BTreeSet of enabled field paths that match specified patterns.

This macro checks which fields are enabled and formats them according to the provided patterns. It supports multiple outputs per field using the ; separator for cases where one field should map to multiple output values. Field paths use dot notation for nested access.

Examples

let mut selector = user.serialize_fields();
selector.enable_dot_hierarchy("id");
selector.enable_dot_hierarchy("name");
selector.enable_dot_hierarchy("profile.bio");

// Single output per field
let field_set = filter_field_set!(selector, {
    id => format!("user_id"),
    name => format!("user_name"),
    profile.bio => format!("profile_bio"),
    profile.avatar => format!("profile_avatar")
});

// Multiple outputs per field using ; separator
let multi_field_set = filter_field_set!(selector, {
    id => "user_id".to_string() ; "id".to_string() ; "primary_key".to_string(),
    name => "user_name".to_string() ; "username".to_string(),
    profile.bio => "bio".to_string() ; "biography".to_string() ; "profile_bio".to_string(),
});

// Only enabled fields are included (all outputs for that field)
assert!(multi_field_set.contains("user_id"));
assert!(multi_field_set.contains("id"));
assert!(multi_field_set.contains("primary_key"));
assert!(multi_field_set.contains("bio"));
assert!(multi_field_set.contains("biography"));
assert!(multi_field_set.contains("profile_bio"));