qmk_firmware/keyboards/roadkit/keymaps/default/keymap.c

#include "roadkit.h"
#include "action_layer.h"
#include "eeconfig.h"

extern keymap_config_t keymap_config;

// Each layer gets a name for readability, which is then used in the keymap matrix below.
// The underscores don't mean anything - you can have a layer called STUFF or any other name.
// Layer names don't all need to be of the same length, obviously, and you can also skip them
// entirely and just use numbers.

#define _NP 0

// Macro name shortcuts
#define NUMPAD M(_NP)

// Fillers to make layering more clear
#define _______ KC_TRNS
#define XXXXXXX KC_NO


const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
  [_NP] = /* Numpad */
    KEYMAP(KC_KP_7, KC_KP_8,   KC_KP_9, KC_KP_PLUS,  \
           KC_KP_4, KC_KP_5,   KC_KP_6,              \
           KC_KP_1, KC_KP_2,   KC_KP_3, KC_KP_ENTER, \
           KC_KP_0,            KC_KP_DOT),
};

const uint16_t PROGMEM fn_actions[] = {

};

void persistant_default_layer_set(uint16_t default_layer) {
  eeconfig_update_default_layer(default_layer);
  default_layer_set(default_layer);
}

const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt)
{
      switch(id) {
        case _NP:
          if (record->event.pressed) {
            persistant_default_layer_set(1UL<<_NP);
          }
          break;
      }
    return MACRO_NONE;
};