Made a userspace that allows you to use your keyboard as an order of operations based calculator (#2864)

* Made DZ60 layout with calculator

* Cleaned up and commented, preparing to fix bug with negative in front of open parenthesis as first character

* Fixed bug where negative sign infront of parenthesis as first character was parsed incorrectly

* Made a better solution for the bug from the previous commit

* Modularized and added a userfile so that this code can be used on various keyboards, found in doogle999

* Removed commented code from keymap

* Made the layer that is used for calculations a define so that it can be changed per keyboard

* Made the readme

* Made the readme in the correct place

* Revert "Made the readme in the correct place"

This reverts commit 7f8b59ed9e59c77401a48be3a7ac1e8fd8e84e32.

* Manually synced with qmk upstream

* Stopped repeat, made keys print character that they are defined as rather than what the keyboard wants them to do

* Added support for numpad, might make all keycodes custom so that there is no need to change doogle999.c if you want to change the keycode that is associated with a function, also made numpad automatically activating an option

* Fixed some bugs with backspacing, updated the readme

* Fixed some bugs with numlock turning on at the wrong times when a shift key was down

* Made the return to layer work automatically instead of just forcing it to layer 0

* fixes and style changes, 20% decreased binary size

* Fixed some bugs with double printing and compilation errors on my side

* Fixed bug with exceeding the buffer size

* Removed changes that added const-ness

* Made changes so that backspace does not repeat to remove backspace bugs, still some bugs with recalculating without having typed anything

* Fixed obo error with calc main loop

* Made includes more accurate in keymap for dz60

* Moved flags to user makefile

1 files changed, 41 insertions, 0 deletions

diff --git a/users/doogle999/readme.md b/users/doogle999/readme.md
new file mode 100644
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+++ b/users/doogle999/readme.md
@@ -0,0 +1,41 @@
+Copyright 2018 <name> <email> @doogle999
+
+Overview
+========
+
+This folder is just for some calculator code for my keyboards.
+
+Making Your Keyboard Into A Calculator
+--------------------------------------
+
+If you'd like to make your keyboard into a calculator, you can do it with this userspace (hopefully!)
+
+You can make a keymap for your keyboard of choice named doogle999 and then you can make it regularly.
+
+You should make one layer that is just the functionality for your calculator, so it just has the keys you need (numbers, symbols, some letters for functions). It should also have END_CALC and CALC somewhere. END_CALC gets you out of calculator mode, and CALC evaluates the calculation.
+
+On one of your other keymaps you should make a key that is TO(layer of calculator). This is how you will activate the calculator. You should also define the layer your calculator is on with the define CALC_LAYER in doogle999.h (this means that for all your keyboards, your calculator layer has to be the same layer).
+
+You can change what characters coorespond to what operators and functions and you can add more functions in doogle999.h and doogle999.c, you can also change which characters are sued for which keys. However, as of now standard keys should be used for operations. By that I mean if you want your multiplication sign to be an x, you should change the CALC_CHAR_MUL to an x but you should keep your multiplication keycode on the keymap either as KC_8 (shifted) or KC_KP_ASTERISK. This might be changed in the future so there are custom keycodes so this is less of a pain and more intuitive.
+
+You can look at my dz60 keymap doogle999 for an example.
+
+Issues
+------
+Unfortunately the chip onboard my dz60 only does single precision floating point numbers, but I have everything set up as double so if your chip supports doubles it should work for you.
+
+This Was Here When I Made The ReadMe
+------------------------------------
+
+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.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.
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