Select Word: Revise to avoid possible edge cases.

Motivated by #26,
this commit makes a few tweaks to avoid what look like bugs in certain
edge case situations. Thanks to @windhausen for reporting this:

* On initial press, always clear the non-Shift mods.
* Change uses of `register_code()` on mod keys to `register_mods()`.
* Change uses of `SEND_STRING` to `tap_code()` calls, since the former
  is not supported on non-Latin layouts.
* Mac, don't use the Ctrl+A / Crtl+E , since KC_A and KC_E might be
  remapped to other meanings if the OS is set to a non-US QWERTY layout.
  Instead use GUI+Left / GUI+Right.
* Streamline to eliminate sending a unnecessary keyboard reports around
  setting and clearing mods.

features/select_word.c

@@ -1,4 +1,4 @@
-// Copyright 2021-2022 Google LLC
+// Copyright 2021-2023 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -38,32 +38,40 @@ bool process_select_word(uint16_t keycode, keyrecord_t* record,
   if (keycode == sel_keycode && record->event.pressed) {  // On key press.
     const uint8_t mods = get_mods();
 #ifndef NO_ACTION_ONESHOT
-    const uint8_t all_mods = mods | get_oneshot_mods();
+    const bool shifted = (mods | get_oneshot_mods()) & MOD_MASK_SHIFT;
+    clear_oneshot_mods();
 #else
-    const uint8_t all_mods = mods;
+    const bool shifted = mods & MOD_MASK_SHIFT;
 #endif  // NO_ACTION_ONESHOT
-    if ((all_mods & MOD_MASK_SHIFT) == 0) {  // Select word.
+
+    if (!shifted) {  // Select word.
 #ifdef MAC_HOTKEYS
-      register_code(KC_LALT);
+      set_mods(MOD_BIT(KC_LALT));
 #else
-      register_code(KC_LCTL);
+      set_mods(MOD_BIT(KC_LCTL));
 #endif  // MAC_HOTKEYS
       if (state == STATE_NONE) {
-        SEND_STRING(SS_TAP(X_RGHT) SS_TAP(X_LEFT));
+        send_keyboard_report();
+        tap_code(KC_RGHT);
+        tap_code(KC_LEFT);
       }
-      register_code(KC_LSFT);
+      register_mods(MOD_BIT(KC_LSFT));
       register_code(KC_RGHT);
       state = STATE_WORD;
     } else {  // Select line.
       if (state == STATE_NONE) {
-        clear_mods();
-#ifndef NO_ACTION_ONESHOT
-        clear_oneshot_mods();
-#endif  // NO_ACTION_ONESHOT
 #ifdef MAC_HOTKEYS
-        SEND_STRING(SS_LCTL("a" SS_LSFT("e")));
+        set_mods(MOD_BIT(KC_LGUI));
+        send_keyboard_report();
+        tap_code(KC_LEFT);
+        register_mods(MOD_BIT(KC_LSFT));
+        tap_code(KC_RGHT);
 #else
-        SEND_STRING(SS_TAP(X_HOME) SS_LSFT(SS_TAP(X_END)));
+        clear_mods();
+        send_keyboard_report();
+        tap_code(KC_HOME);
+        register_mods(MOD_BIT(KC_LSFT));
+        tap_code(KC_END);
 #endif  // MAC_HOTKEYS
         set_mods(mods);
         state = STATE_FIRST_LINE;
@@ -79,11 +87,10 @@ bool process_select_word(uint16_t keycode, keyrecord_t* record,
   switch (state) {
     case STATE_WORD:
       unregister_code(KC_RGHT);
-      unregister_code(KC_LSFT);
 #ifdef MAC_HOTKEYS
-      unregister_code(KC_LALT);
+      unregister_mods(MOD_BIT(KC_LSFT) | MOD_BIT(KC_LALT));
 #else
-      unregister_code(KC_LCTL);
+      unregister_mods(MOD_BIT(KC_LSFT) | MOD_BIT(KC_LCTL));
 #endif  // MAC_HOTKEYS
       state = STATE_SELECTED;
       break;
@@ -103,7 +110,7 @@ bool process_select_word(uint16_t keycode, keyrecord_t* record,
         state = STATE_NONE;
         return false;
       }
-      // Fallthrough.
+      // Fallthrough intended.
     default:
       state = STATE_NONE;
   }