Macro gatt_services 

macro_rules! gatt_services {
    (@uuid_ptr $uuid:expr) => { ... };
    (@chr $uuid:expr, $($flag:ident)|+ ) => { ... };
    (@primary primary) => { ... };
    (@primary secondary) => { ... };
    (@unit $_t:expr) => { ... };
    (
        $vis:vis $NAME:ident {
            $(
                $kind:ident ( $svc_uuid:expr ) {
                    $( chr ( $chr_uuid:expr, $($flag:ident)|+ ) ; )*
                }
            )+
        }
    ) => { ... };
}

Define a static (compile-time, heap-free) GATT service table.

Expands to a static NAME holding the null-terminated NimBLE ble_gatt_svc_def tree (services, characteristics, UUIDs), all in flash. Pass &NAME to new_with_services. Reads and writes are serviced the same way as the runtime table — through the single gatts_subscribe hook, keyed by the value handle reported in the Register events (so learn handles there, exactly as the runtime example does).

Each UUID slot is any const BleUuid expression — declare your UUIDs as const FOO: BleUuid = BleUuid::uuid128(..) (or uuid16) and name them. Characteristic flags are any |-separated BleGattCharFlag variants (Read, Write, Notify, Indicate). Services are primary(..) or secondary(..).

The NAME and the body live inside the one macro group (a macro invocation is a single token tree), so it reads gatt_services!(NAME { .. }); — use !{ .. } to drop the trailing ;.

use esp_idf_svc::ble::BleUuid;
use esp_idf_svc::gatt_services;

const SVC: BleUuid = BleUuid::uuid128(0xad91b201_73474047_9e173bed_82d75f9d);
const RECV: BleUuid = BleUuid::uuid128(0xb6fccb50_87be44f3_ae22f854_85ea42c4);
const HR: BleUuid = BleUuid::uuid16(0x2A37);

gatt_services!(SERVICES {
    primary(SVC) {
        chr(RECV, Write);
        chr(HR, Notify | Indicate);
    }
});
// ... let driver = BleDriver::new_with_services(modem, &SERVICES)?;