qmk_firmware_custom/keyboards/acr60/keymaps/default/keymap.c

#include QMK_KEYBOARD_H

#define MODS_CTRL_MASK  (MOD_BIT(KC_LSHIFT)|MOD_BIT(KC_RSHIFT))

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {

/*
 * Default keymap with standard 60% layout. Split space possible but entirely optional with this layout, as this
 * layout covers all three split space keys as space keycodes. This also has alt right next to the space bar
 * on both sides (Windows keyboard layout), no right-side system/GUI key, and momentary layer switching on
 * the right modifiers into the 3rd (macro) and 2nd (function/sfx) layers, respectively. This also has the grave
 * accent key set up on the 2nd layer, although on the first layer it includes grave key (tilde) when shift is held down,
 * via the function actions code at the bottom.
 */
	LAYOUT(
		F(0), KC_1, KC_2, KC_3, KC_4, KC_5, KC_6, KC_7, KC_8, KC_9, KC_0, KC_MINS, KC_EQL, KC_NO, KC_BSPC,
		KC_TAB, KC_Q, KC_W, KC_E, KC_R, KC_T, KC_Y, KC_U, KC_I, KC_O, KC_P, KC_LBRC, KC_RBRC, KC_BSLS,
		KC_CAPS, KC_A, KC_S, KC_D, KC_F, KC_G, KC_H, KC_J, KC_K, KC_L, KC_SCLN, KC_QUOT, KC_ENT,
		KC_LSFT, KC_NO, KC_Z, KC_X, KC_C, KC_V, KC_B, KC_N, KC_M, KC_COMM, KC_DOT, KC_SLSH, KC_RSFT, KC_NO,
		KC_LCTL, KC_LGUI, KC_LALT, KC_SPC, KC_SPC, KC_SPC, KC_RALT, MO(2), KC_NO, MO(1), KC_RCTL),

	LAYOUT(
		KC_GRV, KC_F1, KC_F2, KC_F3, KC_F4, KC_F5, KC_F6, KC_F7, KC_F8, KC_F9, KC_F10, KC_F11, KC_F12, KC_TRNS, KC_DEL,
		KC_TRNS, RGB_TOG, RGB_MOD, RGB_HUI, RGB_HUD, RGB_SAI, RGB_SAD, RGB_VAI, RGB_VAD, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, RESET,
		KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS,
		KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, BL_DEC, BL_TOGG, BL_INC, BL_STEP, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS,
		KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS),

	LAYOUT(
		KC_TRNS, M(1), M(2), M(3), M(4), M(5), M(6), M(7), M(8), M(9), M(10), M(11), M(12), KC_TRNS, KC_TRNS,
		KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS,
		KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS,
		KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS,
		KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS),
};

enum function_id {
    SHIFT_ESC,
};

const uint16_t PROGMEM fn_actions[] = {
  [0]  = ACTION_FUNCTION(SHIFT_ESC),
};

void action_function(keyrecord_t *record, uint8_t id, uint8_t opt) {
  static uint8_t shift_esc_shift_mask;
  switch (id) {
    case SHIFT_ESC:
      shift_esc_shift_mask = get_mods()&MODS_CTRL_MASK;
      if (record->event.pressed) {
        if (shift_esc_shift_mask) {
          add_key(KC_GRV);
          send_keyboard_report();
        } else {
          add_key(KC_ESC);
          send_keyboard_report();
        }
      } else {
        if (shift_esc_shift_mask) {
          del_key(KC_GRV);
          send_keyboard_report();
        } else {
          del_key(KC_ESC);
          send_keyboard_report();
        }
      }
      break;
  }
}