[Keymap] Unicode and Pointing Device and Autocorect for drashna keymaps (#15415)

users/drashna/readme/handlers.md

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+# Custom Userspace Function handlers
+
+Specifically QMK works by using customized handlers for everything. This allows for multiple levels of customization. 
+
+`matrix_scan` calls `matrix_scan_quantum`, which calls `matrix_scan_kb`, which calls `matrix_scan_user`. 
+`process_record` calls a bunch of stuff, but eventually calls `process_record_kb` which calls `process_record_user`
+The same goes for `matrix_init`, `layer_state_set`, `led_set`, and a few other functions.  
+
+All (most) `_user` functions are handled here, in the userspace instead.  To allow keyboard specific configuration, I've created `_keymap` functions that can be called by the keymap.c files instead.
+
+This allows for keyboard specific configuration while maintaining the ability to customize the board.
+
+My [Ergodox EZ Keymap](https://github.com/qmk/qmk_firmware/blob/master/layouts/community/ergodox/drashna/keymap.c) is a good example of this, as it uses the LEDs as modifier indicators.
+
+But for a list: 
+
+```c
+__attribute__ ((weak))
+void matrix_init_keymap(void) {}
+
+void matrix_init_user(void) {
+  matrix_init_keymap();
+}
+
+__attribute__((weak))
+void keyboard_post_init_keymap(void){ }
+
+void keyboard_post_init_user(void){
+    keyboard_post_init_keymap();
+}
+
+__attribute__ ((weak))
+void matrix_scan_keymap(void) {}
+
+void matrix_scan_user(void) {
+  matrix_scan_keymap();
+}
+
+
+__attribute__ ((weak))
+bool process_record_keymap(uint16_t keycode, keyrecord_t *record) {
+  return true;
+}
+
+bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+  return process_record_keymap(keycode, record);
+}
+
+
+__attribute__ ((weak))
+layer_state_t layer_state_set_keymap (layer_state_t state) {
+  return state;
+}
+
+layer_state_t layer_state_set_user (layer_state_t state) {
+  return layer_state_set_keymap (state);
+}
+
+
+__attribute__ ((weak))
+void led_set_keymap(uint8_t usb_led) {}
+
+void led_set_user(uint8_t usb_led) {
+   led_set_keymap(usb_led);
+}
+
+
+__attribute__ ((weak))
+void suspend_power_down_keymap(void) {}
+
+void suspend_power_down_user(void) {
+    suspend_power_down_keymap();
+}
+
+
+__attribute__ ((weak))
+void suspend_wakeup_init_keymap(void) {}
+
+void suspend_wakeup_init_user(void) {
+  suspend_wakeup_init_keymap();
+}
+
+
+__attribute__ ((weak))
+void shutdown_keymap(void) {}
+
+void shutdown_user (void) {
+  shutdown_keymap();
+}
+
+__attribute__ ((weak))
+void eeconfig_init_keymap(void) {}
+
+void eeconfig_init_user(void) {
+  eeconfig_init_keymap();
+}
+```