Update to the Userspace documentation (#4005)

* Overhaul to Userspace Documentation

* Formatting issues

* Additionaly formatting fixes

* Add Readme info

* Additionaly Readme info

* Formatting fixes

docs/feature_userspace.md

@@ -5,15 +5,12 @@ If you use more than one keyboard with a similar keymap, you might see the benef
 * `/users/<name>/` (added to the path automatically)
   * `readme.md` (optional, recommended)
   * `rules.mk` (included automatically)
+  * `config.h` (included automatically)
   * `<name>.h` (optional)
   * `<name>.c` (optional)
-  * `config.h` (optional)
+  * `cool_rgb_stuff.c` (optional)
+  * `cool_rgb_stuff.h` (optional)
 
-`<name>.c` will need to be added to the SRC in `rules.mk` like this:
-
-    SRC += <name>.c
-
-Additional files may be added in the same way - it's recommended you have one named `<name>`.c/.h though.
 
 All this only happens when you build a keymap named `<name>`, like this:
 
@@ -25,80 +22,177 @@ For example,
 
 Will include the `/users/jack/` folder in the path, along with `/users/jack/rules.mk`.  
 
+!> This `name` can be [overridden](#override-default-userspace), if needed.  
+
+## `Rules.mk`
+
+The `rules.mk` is one of the two files that gets processed automatically.  This is how you add additional source files (such as  `<name>.c`) will be added when compiling.
+
+It's highly recommended that you use `<name>.c` as the default source file to be added. And to add it, you need to add it the SRC in `rules.mk` like this:
+
+    SRC += <name>.c
+
+Additional files may be added in the same way - it's recommended you have one named `<name>`.c/.h to start off with, though. 
+
+The `/users/<name>/rules.mk` file will be included in the build _after_ the `rules.mk` from your keymap. This allows you to have features in your userspace `rules.mk` that depend on individual QMK features that may or may not be available on a specific keyboard. 
+
+For example, if you have RGB control features shared between all your keyboards that support RGB lighting, you can add support for that if the RGBLIGHT feature is enabled:
+```make
+ifeq ($(strip $(RGBLIGHT_ENABLE)), yes)
+  # Include my fancy rgb functions source here
+  SRC += cool_rgb_stuff.c
+endif
+```
+
+Alternatively, you can `define RGB_ENABLE` in your keymap's `rules.mk` and then check for the variable in your userspace's `rules.mk` like this:
+```make
+ifdef RGB_ENABLE
+  # Include my fancy rgb functions source here
+  SRC += cool_rgb_stuff.c
+endif
+```
+
+### Override default userspace
+
+By default the userspace used will be the same as the keymap name. In some situations this isn't desirable. For instance, if you use the [layout](feature_layouts.md) feature you can't use the same name for different keymaps (e.g. ANSI and ISO). You can name your layouts `mylayout-ansi` and `mylayout-iso` and add the following line to your layout's `rules.mk`:
+
+```
+USER_NAME := mylayout
+```
+
+This is also useful if you have multiple different keyboards with different features physically present on the board (such as one with RGB Lights, and one with Audio, or different number of LEDs, or connected to a different PIN on the controller).
+
+## Configuration Options (`config.h`)
+
 Additionally, `config.h` here will be processed like the same file in your keymap folder.  This is handled separately from the `<name>.h` file.
 
 The reason for this, is that `<name>.h` won't be added in time to add settings (such as `#define TAPPING_TERM 100`), and including the `<name.h>` file in any `config.h` files will result in compile issues.
 
-So you should use the `config.h` for QMK settings, and the `<name>.h` file for user or keymap specific settings.
+!>You should use the `config.h` for [configuration options](config_options.md), and the `<name>.h` file for user or keymap specific settings (such as the enum for layer or keycodes)
 
-`/users/<name>/rules.mk` will be included in the build _after_ the `rules.mk` from your keymap. This allows you to have features in your userspace `rules.mk` that depend on individual QMK features that may or may not be available on a specific keyboard. For example, if you have RGB control features shared between all your keyboards that support RGB lighting, you can `define RGB_ENABLE` in your keymap `rules.mk` and then check for the variable in your userspace `rules.mk` like this:
-```make
-ifdef RGB_ENABLE
-    # Include my fancy rgb functions source here
-endif
-```
-Because of this, any time you turn on QMK features in your `users/<name>/rules.mk`, you should conditionally enable them only if the flag isn't already defined, like this:
-```make
-ifndef TAP_DANCE_ENABLE
-    TAP_DANCE_ENABLE = yes
-endif
-```
-This will ensure that you can explicitly turn off features for an individual keymap.
 
-## Readme
+## Readme (`readme.md`)
 
 Please include authorship (your name, github username, email), and optionally [a license that's GPL compatible](https://www.gnu.org/licenses/license-list.html#GPLCompatibleLicenses).
 
-## `Config.h`
+You can use this as a template: 
+```
+Copyright <year> <name> <email> @<github_username>
 
-If you do add a `config,h` file, you want to make sure that it only gets processed once.  So you may want to start off with something like this:
+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 2 of the License, or
+(at your option) any later version.
 
-```c
+This program is distributed in the hope that it will be useful,
-#ifndef USERSPACE_CONFIG_H
+but WITHOUT ANY WARRANTY; without even the implied warranty of
-#define USERSPACE_CONFIG_H
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
 
-// Put normal config.h settings here:
+You should have received a copy of the GNU General Public License
-
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
-#endif // !USERSPACE_CONFIG_H
 ```
 
-You can use any option hre that you could use in your keymap's `config.h` file. You can find a list of vales [here](config_options.md).
+You'd want to replace the year, name, email and github username with your info. 
 
-## Example
+Additionally, this is a good place to document your code, if you wish to share it with others. 
 
-For a brief example, checkout `/users/_example/` , or for a more detailed examples check out [`template.h`](https://github.com/qmk/qmk_firmware/blob/master/users/drashna/template.h) and [`template.c`](https://github.com/qmk/qmk_firmware/blob/master/users/drashna/template.c) in `/users/drashna/` .
+# Examples
 
-### Consolidated Macros
+For a brief example, checkout [`/users/_example/`](https://github.com/qmk/qmk_firmware/tree/master/users/drashna).  
+For a more complicaed example, checkout [`/users/drashna/`](https://github.com/qmk/qmk_firmware/tree/master/users/drashna)'s userspace.
 
-If you wanted to consolidate macros and other functions into your userspace for all of your keymaps, you can do that.  The issue is that you then cannot call any function defined in your userspace, or it gets complicated.  To better handle this, you can call the functions here and create new functions to use in individual keymaps.
+
+## Customized Functions
+
+QMK has a bunch of [functions](custom_quantum_functions.md) that have [`_quantum`, `_kb`, and `_user` versions](custom_quantum_functions.md#a-word-on-core-vs-keyboards-vs-keymap) that you can use.  You will pretty much always want to use the user version of these functions.  But the problem is that if you use them in your userspace, then you don't have a version that you can use in your keymap. 
+
+However, you can actually add support for keymap version, so that you can use it in both your userspace and your keymap! 
+
+
+For instance, lets looks at the `layer_state_set_user` function.  Lets enable the [Tri Layer State](ref_functions.md#olkb-tri-layers) functionalitly to all of our boards, and then still have your `keymap.c` still able to use this functionality. 
+
+In your `<name.c>` file, you'd want to add this: 
+```c
+__attribute__ ((weak))
+uint32_t layer_state_set_keymap (uint32_t state) {
+  return state;
+}
+
+uint32_t layer_state_set_user (uint32_t state) {
+  state = update_tri_layer_state(state, 2, 3, 5);
+  return layer_state_set_keymap (state);
+}
+```
+The `__attribute__ ((weak))` part tells the compiler that this is a placce holder function that can then be replaced by a version in your `keymap.c`.  That way, you don't need to add it to your `keymap.c`, but if you do, you won't get any conflicts because the function is the same name. 
+
+The `_keymap` part here doesn't matter, it just needs to be something other than `_quantum`, `_kb`, or `_user`, since those are already in use. So you could use `layer_state_set_mine`, `layer_state_set_fn`, or anything else.
+
+You can see a list of this and other common functions in [`template.c`](https://github.com/qmk/qmk_firmware/blob/master/users/drashna/template.c) in [`users/drashna`](https://github.com/qmk/qmk_firmware/tree/master/users/drashna).
+
+## Custom Features
+
+Since the Userspace feature can support a staggering number of boards, you may have boards that you want to enable certain functionality for, but not for others. And you can actually create "features" that you can enable or disable in your own userspace.  
+
+For instance, if you wanted to have a bunch of macros available, but only on certain boards (to save space), you could "hide" them being a `#ifdef MACROS_ENABLED`, and then enable it per board.  To do this, add this to your rules.mk
+```make
+ifeq ($(strip $(MACROS_ENABLED)), yes)
+    OPT_DEFS += -DMACROS_ENABLED
+endif
+```
+The `OPT_DEFS` setting causee `MACROS_ENABLED` to be defined for your keyboards (note the `-D` in front of the name), and you could use `#ifdef MACROS_ENABLED` to check the status in your c/h files, and handle that code based on that. 
+
+Then you add `MACROS_ENABLED = yes` to the `rules.mk` for you keymap to enable this feature and the code in your userspace.
+
+And in your `process_record_user` function, you'd do something like this: 
+```c
+bool process_record_user(uint16_t keycode, keyrecord_t *record) {
+  switch (keycode) {
+#ifdef MACROS_ENABLED
+  case MACRO1:
+    if (!record->event.pressed) {
+      SEND_STRING("This is macro 1!");
+    }
+    break;
+  case MACRO2:
+    if (!record->event.pressed) {
+      SEND_STRING("This is macro 2!");
+    }
+    break;
+#endif
+  }
+  return true;
+}
+```
+
+
+## Consolidated Macros
+
+If you wanted to consolidate macros and other functions into your userspace for all of your keymaps, you can do that.  This builds upon the [Customized Functions](#customized-functions) example above. This lets you maintain a bunch of macros that are shared between the different keyboards, and allow for keyboard specific macros, too. 
 
 First, you'd want to go through all of your `keymap.c` files and replace `process_record_user` with `process_record_keymap` instead.   This way, you can still use keyboard specific codes on those boards, and use your custom "global" keycodes as well.   You'll also want to replace `SAFE_RANGE` with `NEW_SAFE_RANGE` so that you wont have any overlapping keycodes
 
 Then add `#include <name.h>` to all of your keymap.c files.  This allows you to use these new keycodes without having to redefine them in each keymap.
 
 Once you've done that, you'll want to set the keycode definitions that you need to the `<name>.h`  file. For instance:
-```
+```c
-#ifndef USERSPACE
+#pragma once
-#define USERSPACE
 
 #include "quantum.h"
+#include "action.h"
+#include "version.h"
 
 // Define all of
 enum custom_keycodes {
   KC_MAKE = SAFE_RANGE,
   NEW_SAFE_RANGE  //use "NEW_SAFE_RANGE" for keymap specific codes
 };
-
-#endif
 ```
 
 Now you want to create the `<name>.c` file, and add this content to it:
 
-```
+```c
 #include "<name>.h"
-#include "quantum.h"
-#include "action.h"
-#include "version.h"
 
 __attribute__ ((weak))
 bool process_record_keymap(uint16_t keycode, keyrecord_t *record) {
@@ -130,10 +224,4 @@ This will add a new `KC_MAKE`  keycode that can be used in any of your keymaps.
 
 Additionally, this should flash the newly compiled firmware automatically, using the correct utility, based on the bootloader settings (or default to just generating the HEX file). However, it should be noted that this may not work on all systems. AVRDUDE doesn't work on WSL, namely (and will dump the HEX in the ".build" folder instead).
 
-## Override default userspace
 
-By default the userspace used will be the same as the keymap name. In some situations this isn't desirable. For instance, if you use the [layout](feature_layouts.md) feature you can't use the same name for different keymaps (e.g. ANSI and ISO). You can name your layouts `mylayout-ansi` and `mylayout-iso` and add the following line to your layout's `rules.mk`:
-
-```
-USER_NAME := mylayout
-```