create users/datagrok (#7653)

* users/datagrok: add shared functions

* users/datagrok: improve base-layer selection feature

* users/datagrok: add README.md

1 files changed, 63 insertions, 0 deletions

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+# datagrok's QMK user-space code
+
+## cdeq "comma dot exclamation question"
+
+This is a hack to place `question mark` on `shift-comma` and `exclamation mark` on `shift-period`.
+
+When using an operating system configured for a US/qwerty layout this replaces the angle brackets `<` `>` with `?` `!`. This helps on small keyboards to keep symbols for prose co-located in one layer, and symbols for programming in another.
+
+It's a "hack" because the "proper" way to accomplish this would be to edit the operating system's keymap.
+
+### setup
+
+in your `keymap.c`:
+
+    #include "feature_cdeq.h"
+
+    bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+        return process_record_cdeq(keycode, record);
+    }
+    
+in your `rules.mk`,
+
+    SRC += feature_cdeq.c
+
+### examples
+
+- atreus:datagrok
+- bm43a:datagrok
+- mitosis:datagrok
+
+## base layer selector
+
+Defines a keycode `KF_LAYO` to rotate between available default layers.
+
+`Shift`+`KF_LAYO` makes the currently selected one persistent across reboots.
+
+This is useful if you'd like your keyboard to support and toggle between QWERTY, Dvorak, Colemak, Workman, and other layouts while keeping a common arrangement of modifier and function keys.
+
+Since toggling layouts seems like something one does infrequently, I wanted to be able to operate this feature with a single key, instead of one for each layer like planck:default or bootmagic.
+
+### setup
+
+in your `keymap.c`:
+
+    #define KF_LAYO SAFE_RANGE
+    #include "feature_default_layers_selector.h"
+    const uint8_t highest_base_layer = 4;
+
+    bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+      return \
+        process_record_save_default_layer(keycode, record) && \
+        process_record_select_default_layer(keycode, record);
+    }
+    
+in your `rules.mk`,
+
+    SRC += feature_default_layers_selector.c
+
+### examples
+
+- atreus:datagrok
+- bm43a:datagrok
+- mitosis:datagrok