Macro setup_tracked_struct 

macro_rules! setup_tracked_struct {
    (
        // Attributes on the function.
        attrs: [$(#[$attr:meta]),*],

        // Visibility of the struct.
        vis: $vis:vis,

        // Name of the struct.
        Struct: $Struct:ident,

        // Name of the `'db` lifetime that the user gave.
        db_lt: $db_lt:lifetime,

        // Name user gave for `new`.
        new_fn: $new_fn:ident,

        // Field names.
        field_ids: [$($field_id:ident),*],

        // Tracked field names.
        tracked_ids: [$($tracked_id:ident),*],

        // Visibility and names of tracked fields.
        tracked_getters: [$($tracked_getter_vis:vis $tracked_getter_id:ident),*],

        // Visibility and names of untracked fields.
        untracked_getters: [$($untracked_getter_vis:vis $untracked_getter_id:ident),*],

        // Field types, may reference `db_lt`.
        field_tys: [$($field_ty:ty),*],

        // Tracked field types.
        tracked_tys: [$($tracked_ty:ty),*],

        // Untracked field types.
        untracked_tys: [$($untracked_ty:ty),*],

        // Indices for each field from 0..N -- must be unsuffixed (e.g., `0`, `1`).
        field_indices: [$($field_index:tt),*],

        // Absolute indices of any tracked fields, relative to all other fields of this struct.
        absolute_tracked_indices: [$($absolute_tracked_index:tt),*],

        // Indices of any tracked fields, relative to only tracked fields on this struct.
        relative_tracked_indices: [$($relative_tracked_index:tt),*],

        // Absolute indices of any untracked fields.
        absolute_untracked_indices: [$($absolute_untracked_index:tt),*],

        // Tracked field types.
        tracked_maybe_updates: [$($tracked_maybe_update:tt),*],

        // Untracked field types.
        untracked_maybe_updates: [$($untracked_maybe_update:tt),*],

        // A set of "field options" for each tracked field.
        //
        // Each field option is a tuple `(return_mode, maybe_default)` where:
        //
        // * `return_mode` is an identifier as specified in `salsa_macros::options::Option::returns`
        // * `maybe_default` is either the identifier `default` or `required`
        //
        // These are used to drive conditional logic for each field via recursive macro invocation
        // (see e.g. @return_mode below).
        tracked_options: [$($tracked_option:tt),*],

        // A set of "field options" for each untracked field.
        // (see docs for `tracked_options`).
        untracked_options: [$($untracked_option:tt),*],

        // Attrs for each field.
        tracked_field_attrs: [$([$(#[$tracked_field_attr:meta]),*]),*],
        untracked_field_attrs: [$([$(#[$untracked_field_attr:meta]),*]),*],

        // Number of tracked fields.
        num_tracked_fields: $N:literal,

        // If true, generate a debug impl.
        generate_debug_impl: $generate_debug_impl:tt,

        // The function used to implement `C::heap_size`.
        heap_size_fn: $($heap_size_fn:path)?,

        // If `true`, `serialize_fn` and `deserialize_fn` have been provided.
        persist: $persist:tt,

        // The path to the `serialize` function for the value's fields.
        serialize_fn: $($serialize_fn:path)?,

        // The path to the `serialize` function for the value's fields.
        deserialize_fn: $($deserialize_fn:path)?,

        // Annoyingly macro-rules hygiene does not extend to items defined in the macro.
        // We have the procedural macro generate names for those items that are
        // not used elsewhere in the user's code.
        unused_names: [
            $zalsa:ident,
            $zalsa_struct:ident,
            $Configuration:ident,
            $CACHE:ident,
            $Db:ident,
            $Revision:ident,
        ]
    ) => { ... };
}

Macro for setting up a function that must intern its arguments.