[Keymap] Neo2 for ErgoDox on MacOS US QWERTY / ABC Extended keymap (#5862)

This is a Neo2 inspired layout that is meant to be fully usable on
MacOS when used with the default US QWERTY/ABC Extended keymap.

Neo2 layers 1-4 have been almost fully implemented in hardware.
Layers 5 and 6 (greek and mathematical symbols) have been left
out for now as most of them aren't available on the default
keymaps.

Layer toggling for layer 3 on the right hand side utilizes a
tap-toggle approach that is a combination of MO & LT macros.
This is required to allow sending Y when tapped, @ when tapped
while the SHIFT modifier is active and support momentarily
toggling the layer while the key is held.

1 files changed, 219 insertions, 0 deletions

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+# Neo 2 for ErgoDox on QWERTY
+
+# Description
+
+The Neo layout is an optimized German keyboard layout developed by the 
+Neo Users Group, supporting many Latin-based alphabets. The positions 
+of the letters are not only optimized for German letter frequency, 
+but also for typical groups of two or three letters.  English is 
+considered a primary target as well. 
+
+The design tries to enforce the alternating usage of both hands to 
+increase typing speed  and incorporates ideas from de-ergo and other 
+ergonomic layouts. High frequency keys are placed in the home row. 
+The current layout Neo 2.0 has unique features making it suited for 
+many target groups such as programmers, mathematicians, scientists or 
+LaTeX authors.
+
+Neo is grouped into six layers, each dedicated to a special purpose.
+
+# Layers
+
+At the core this is a Neo 2.0 layout adjusted for the Ergodox Infinity. 
+The keymap is laid out expecting a macOs using the US QWERTY or ABC 
+Extended layout. 
+
+[Layer 1](#layer-1) Lowercase, upppercase and typographical  characters
+
+[Layer 2](#layer-2) Special characters for programming
+
+[Layer 3](#layer-3) WASD-like movement keys and number block
+
+[Layer 4](#layer-4) Greek characters
+
+[Layer 5](#layer-5) Mathematical symbols and Greek uppercase characters
+
+[Layer 6](#layer-6) Ergodox Infinity US QWERTY layout
+
+[Layer 7](#layer-7) Function keys
+
+## Legend
+
+ * Keys marked with `----` are dead keys.
+ * Blank keys are transparent and fall through to lower levels.
+
+## Layer 1
+
+This layer implements NEO layers 1 and 2.
+
+```
+,--------------------------------------------------.           ,--------------------------------------------------.
+|  ----  |  1/° |  2/§ |  3/  |  4/» |  5/« |  ESC |           | US_1 |  6/$ |  7/€ |  8/„ |  9/“ |  0/” |  -/—   |
+|--------+------+------+------+------+-------------|           |------+------+------+------+------+------+--------|
+|  TAB   |   X  |   V  |   L  |   C  |   W  | LCTL |           | RCTL |   K  |   H  |   G  |   F  |   Q  |   ß    |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|  NEO_3 |   U  |   I  |   A  |   E  |   O  |------|           |------|   S  |   N  |   R  |   T  |   D  |   Y    |
+|--------+------+------+------+------+------| LALT |           | RALT |------+------+------+------+------+--------|
+| LSHIFT |   Ü  |   Ö  |   Ä  |   P  |   Z  |      |           |      |   B  |   M  |  ,/– |  ./• |   J  | RSHIFT |
+`--------+------+------+------+------+-------------'           `-------------+------+------+------+------+--------'
+  | ---- | ---- | LCTL | LALT | LGUI |                                       | RGUI | Left | Down |  Up  | Right|
+  `----------------------------------'                                       `----------------------------------'
+                                       ,-------------.       ,-------------.
+                                       | FKEYS| Home |       | PgUp | FKEYS|
+                                ,------|------|------|       |------+------+------.
+                                | Back-|      | End  |       | PgDn |      |      |
+                                | space|Delete|------|       |------| Enter|Space |
+                                |      |      | NEO_4|       | NEO_4|      |      |
+                                `--------------------'       `--------------------'
+```
+
+## Layer 2
+
+This layer implements NEO layer 3.
+
+
+```
+,--------------------------------------------------.           ,--------------------------------------------------.
+|  ----  | ---- | ---- | ---- |   ›  |   ‹  |      |           |      |   ¢ 	|   ¥  |   ‚  |   ‘  |   ’  |  ----  |
+|--------+------+------+------+------+-------------|           |------+------+------+------+------+------+--------|
+|  ----  |   …  |   _  |   [  |   ]  |   ^  |      |           |      |   !  |   <  |   >  |   =  |   &  |  ----  |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|        |   \  |   /  |   {  |   }  |   *  |------|           |------|   ?  |   (  |   )  |   -  |   :  |   @    |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|        |   #  |   $  |   |  |   ~  |   `  |      |           |      |   +  |   %  |   "  |   '  |   ;  |        |
+`--------+------+------+------+------+-------------'           `-------------+------+------+------+------+--------'
+  |      |      |      |      |      |                                       |      |      |      |      |      |
+  `----------------------------------'                                       `----------------------------------'
+                                       ,-------------.       ,-------------.
+                                       |      |      |       |      |      |
+                                ,------|------|------|       |------+------+------.
+                                |      |      |      |       |      |      |      |
+                                |      |      |------|       |------|      |      |
+                                |      |      |      |       |      |      |      |
+                                `--------------------'       `--------------------'
+```
+
+## Layer 3
+
+This layer implements NEO layer 4.
+
+```
+,--------------------------------------------------.           ,--------------------------------------------------.
+|  ----  |   ª  |   º  | ---- |   ·  |   £  |      |           |      | ---- | Tab  |   /  |   *  |   -  |  ----  |
+|--------+------+------+------+------+-------------|           |------+------+------+------+------+------+--------|
+|  ----  | PgUp |   ⌫  |  Up  |   ⌦  | PgDn |      |           |      |   ¡  |   7  |   8  |   9  |   +  |   –    |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|        | Home | Left | Down | Right| End  |------|           |------|   ¿  |   4  |   5  |   6  |   ,  |   .    |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|        | Esc  | Tab  | Ins  |Return| ---- |      |           |      |   :  |   1  |   2  |   3  |   ;  |        |
+`--------+------+------+------+------+-------------'           `-------------+------+------+------+------+--------'
+  |      |      |      |      |      |                                       |      |   0  |      |      |      |
+  `----------------------------------'                                       `----------------------------------'
+                                       ,-------------.       ,-------------.
+                                       |      |      |       |      |      |
+                                ,------|------|------|       |------+------+------.
+                                |      |      |      |       |      |      |      |
+                                |      |      |------|       |------|      |      |
+                                |      |      |      |       |      |      |      |
+                                `--------------------'       `--------------------'
+```
+
+## Layer 4
+
+This layer is currently empty/reserved for NEO layer 5.
+
+```
+,--------------------------------------------------.           ,--------------------------------------------------.
+|  ----  | ---- | ---- | ---- | ---- | ---- |      |           |      | ---- | ---- | ---- | ---- | ---- |  ----  |
+|--------+------+------+------+------+-------------|           |------+------+------+------+------+------+--------|
+|  ----  | ---- | ---- | ---- | ---- | ---- |      |           |      | ---- | ---- | ---- | ---- | ---- |  ----  |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|        | ---- |  ----| ---- | ---- | ---- |------|           |------| ---- | ---- | ---- | ---- | ---- |  ----  |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|        | ---- |  ----| ---- | ---- | ---- |      |           |      | ---- | ---- | ---- | ---- | ---- |        |
+`--------+------+------+------+------+-------------'           `-------------+------+------+------+------+--------'
+  |      |      |      |      |      |                                       |      |      |      |      |      |
+  `----------------------------------'                                       `----------------------------------'
+                                       ,-------------.       ,-------------.
+                                       |      |      |       |      |      |
+                                ,------|------|------|       |------+------+------.
+                                |      |      |      |       |      |      |      |
+                                |      |      |------|       |------|      |      |
+                                |      |      |      |       |      |      |      |
+                                `--------------------'       `--------------------'
+```
+
+## Layer 5
+
+This layer is currently empty/reserved for NEO layer 6.
+
+```
+,--------------------------------------------------.           ,--------------------------------------------------.
+|  ----  | ---- | ---- | ---- | ---- | ---- |      |           |      | ---- | ---- | ---- | ---- | ---- |  ----  |
+|--------+------+------+------+------+-------------|           |------+------+------+------+------+------+--------|
+|  ----  | ---- | ---- | ---- | ---- | ---- |      |           |      | ---- | ---- | ---- | ---- | ---- |  ----  |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|        | ---- |  ----| ---- | ---- | ---- |------|           |------| ---- | ---- | ---- | ---- | ---- |  ----  |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|        | ---- |  ----| ---- | ---- | ---- |      |           |      | ---- | ---- | ---- | ---- | ---- |        |
+`--------+------+------+------+------+-------------'           `-------------+------+------+------+------+--------'
+  |      |      |      |      |      |                                       |      |      |      |      |      |
+  `----------------------------------'                                       `----------------------------------'
+                                       ,-------------.       ,-------------.
+                                       |      |      |       |      |      |
+                                ,------|------|------|       |------+------+------.
+                                |      |      |      |       |      |      |      |
+                                |      |      |------|       |------|      |      |
+                                |      |      |      |       |      |      |      |
+                                `--------------------'       `--------------------'
+```
+
+## Layer 6
+
+A bare bones implementation of the default Ergodox Infinity layout.
+
+```
+,--------------------------------------------------.           ,--------------------------------------------------.
+|   =    |   1  |   2  |   3  |   4  |   5  | ESC  |           | NEO_1|   6  |   7  |   8  |   9  |   0  |    -   |
+|--------+------+------+------+------+-------------|           |------+------+------+------+------+------+--------|
+|   \    |   Q  |   W  |   E  |   R  |   T  | ---- |           |   [  |   Y  |   U  |   I  |   O  |   P  |    ]   |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|  TAB   |   A  |   S  |   D  |   F  |   G  |------|           |------|   H  |   J  |   K  |   L  |   ;  |    '   |
+|--------+------+------+------+------+------| ---- |           | ---- |------+------+------+------+------+--------|
+| LSHIFT |   Z  |   X  |   V  |   B  |   M  |      |           |      |   N  |   M  |   ,  |   .  |   /  | RSHIFT |
+`--------+------+------+------+------+-------------'           `-------------+------+------+------+------+--------'
+  | LGUI |   `  | ---- | ---- | FKEYS|                                       | Left | Down |  Up  | Right| RGUI |
+  `----------------------------------'                                       `----------------------------------'
+                                       ,-------------.       ,-------------.
+                                       | LCTRL| LALT |       | RALT | RCTRL|
+                                ,------|------|------|       |------+------+------.
+                                |      |      | HOME |       | PGUP |      |      |
+                                | BKSP | DEL  |------|       |------| ENTR | SPCE |
+                                |      |      | END  |       | PGDN |      |      |
+                                `--------------------'       `--------------------'
+```
+
+## Layer 7
+
+This layer implements function and multimedia keys.
+
+```
+,--------------------------------------------------.           ,--------------------------------------------------.
+|  Prev  |  F1  |  F2  |  F3  |  F4  |  F5  |  F11 |           |  F12 |  F6  |  F7  |  F8  |  F9  |  F10 |  VolUp |
+|--------+------+------+------+------+-------------|           |------+------+------+------+------+------+--------|
+|  Play  |      |      |      |      |      |      |           |      |      |      |      |      |      |  VolDn |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|  Next  |      |      |      |      |      |------|           |------|      |      |      |      |      |  Mute  |
+|--------+------+------+------+------+------|      |           |      |------+------+------+------+------+--------|
+|        |      |      |      |      |      |      |           |      |      |      |      |      |      |        |
+`--------+------+------+------+------+-------------'           `-------------+------+------+------+------+--------'
+  |      |      |      |      |      |                                       |      |      |      |      |      |
+  `----------------------------------'                                       `----------------------------------'
+                                       ,-------------.       ,-------------.
+                                       |      |      |       |      |      |
+                                ,------|------|------|       |------+------+------.
+                                |      |      |      |       |      |      |      |
+                                |      |      |------|       |------|      |      |
+                                |      |      |      |       |      |      |      |
+                                `--------------------'       `--------------------'
+```