[Keymap] Add paulomp90 lily58 keymap (#20327)

Co-authored-by: Drashna Jaelre <drashna@live.com>

keyboards/lily58/keymaps/paulomp90/features/custom_shift_keys.c

@@ -0,0 +1,67 @@
+/* Copyright 2023 Paulo Pereira
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "custom_shift_keys.h"
+
+bool process_custom_shift_keys(uint16_t keycode, keyrecord_t *record) {
+  static uint16_t registered_keycode = KC_NO;
+
+  // If a custom shift key is registered, then this event is either
+  // releasing it or manipulating another key at the same time. Either way,
+  // we release the currently registered key.
+  if (registered_keycode != KC_NO) {
+    unregister_code16(registered_keycode);
+    registered_keycode = KC_NO;
+  }
+
+  if (record->event.pressed) {  // Press event.
+    const uint8_t mods = get_mods();
+#ifndef NO_ACTION_ONESHOT
+    if ((mods | get_weak_mods() | get_oneshot_mods()) & MOD_MASK_SHIFT) {
+#else
+    if ((mods | get_weak_mods()) & MOD_MASK_SHIFT) {  // Shift is held.
+#endif  // NO_ACTION_ONESHOT
+      // Continue default handling if this is a tap-hold key being held.
+      if ((IS_QK_MOD_TAP(keycode) || IS_QK_LAYER_TAP(keycode)) &&
+          record->tap.count == 0) {
+        return true;
+      }
+
+      // Search for a custom shift key whose keycode is `keycode`.
+      for (int i = 0; i < NUM_CUSTOM_SHIFT_KEYS; ++i) {
+        if (keycode == custom_shift_keys[i].keycode) {
+          registered_keycode = custom_shift_keys[i].shifted_keycode;
+          if (IS_QK_MODS(registered_keycode) &&  // Should key be shifted?
+              (QK_MODS_GET_MODS(registered_keycode) & MOD_LSFT) != 0) {
+            register_code16(registered_keycode);  // If so, press directly.
+          } else {
+            // If not, cancel shift mods, press the key, and restore mods.
+            del_weak_mods(MOD_MASK_SHIFT);
+#ifndef NO_ACTION_ONESHOT
+            del_oneshot_mods(MOD_MASK_SHIFT);
+#endif  // NO_ACTION_ONESHOT
+            unregister_mods(MOD_MASK_SHIFT);
+            register_code16(registered_keycode);
+            set_mods(mods);
+          }
+          return false;
+        }
+      }
+    }
+  }
+
+  return true;  // Continue with default handling.
+}

keyboards/lily58/keymaps/paulomp90/features/custom_shift_keys.h

@@ -0,0 +1,29 @@
+/* Copyright 2023 Paulo Pereira
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#pragma once
+#include QMK_KEYBOARD_H
+
+typedef struct {
+  uint16_t keycode;
+  uint16_t shifted_keycode;
+} custom_shift_key_t;
+
+extern const custom_shift_key_t custom_shift_keys[];
+extern uint8_t NUM_CUSTOM_SHIFT_KEYS;
+
+bool process_custom_shift_keys(uint16_t keycode, keyrecord_t *record);