Workman QMK layout

config.h

#define TAPPING_TOGGLE 5
#define ONESHOT_TAP_TOGGLE 1
#define PREVENT_STUCK_MODIFIERS

keymap.c

// this is the style you want to emulate.
// This is the canonical layout file for the Quantum project. If you want to add another keyboard,

#include QMK_KEYBOARD_H

// Each layer gets a name for readability, which is then used in the keymap matrix below.
// The underscores don't mean anything - you can have a layer called STUFF or any other name.
// Layer names don't all need to be of the same length, obviously, and you can also skip them
// entirely and just use numbers.
#define _QW 0
#define _RS 1
#define _LW 2

#define GUI_HLD GUI_T(KC_NO)
#define OSM_SFT OSM(MOD_LSFT)

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
  [_QW] = LAYOUT( /* Workman */
    KC_Q,    KC_W,    KC_D,    KC_R,    KC_Y,                      KC_J,    KC_U,    KC_F,    KC_P,    KC_SCLN ,
    KC_A,    KC_S,    KC_H,    KC_T,    KC_G,                      KC_M,    KC_N,    KC_E,    KC_O,    KC_I    ,
    KC_Z,    KC_X,    KC_C,    KC_V,    KC_B,                      KC_K,    KC_L,    KC_COMM, KC_DOT,  KC_SLSH ,
    KC_ESC, KC_TAB, GUI_HLD,  OSM_SFT, KC_BSPC,  KC_LALT, KC_LCTL, KC_SPC,  TT(_RS), TT(_LW), KC_QUOT, KC_ENT
  ),

  /*
   *  !       @     up     {    }        ||     pgup    7     8     9    *
   *  #     left   down  right  $        ||     pgdn    4     5     6    +
   *  [       ]      (     )    &        ||       `     1     2     3    \
   * lower  insert super shift bksp ctrl || alt space   fn    .     0    =
   */
  [_RS] = LAYOUT( /* [> RAISE <] */
    KC_EXLM, KC_AT,   KC_LCBR, KC_RCBR, KC_PIPE,                   KC_MINS, KC_7,    KC_8,    KC_9, KC_ASTR ,
    KC_HASH, KC_DLR,  KC_LPRN, KC_RPRN, KC_GRV,                    KC_UNDS, KC_4,    KC_5,    KC_6, KC_PLUS ,
    KC_PERC, KC_CIRC, KC_LBRC, KC_RBRC, KC_TILD,                   KC_AMPR, KC_1,    KC_2,    KC_3, KC_BSLS ,
    KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_DELT, KC_TRNS, KC_TRNS, KC_INS,  KC_TRNS, KC_TRNS, KC_0, KC_EQL ),
  /*
   * insert home   up  end   pgup       ||      up     F7    F8    F9   F10
   *  del   left  down right pgdn       ||     down    F4    F5    F6   F11
   *       volup             reset      ||             F1    F2    F3   F12
   *       voldn  super shift bksp ctrl || alt space   L0  prtsc scroll pause
   */
  [_LW] = LAYOUT( /* [> LOWER <] */
    KC_INS,  KC_HOME, KC_UP,   KC_END,  KC_PGUP,                   KC_UP,   KC_F7,   KC_F8,   KC_F9,   KC_F10 ,
    KC_DELT, KC_LEFT, KC_DOWN, KC_RGHT, KC_DOWN,                   KC_DOWN, KC_F4,   KC_F5,   KC_F6,   KC_F11 ,
    KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS,                   KC_TRNS, KC_F1,   KC_F2,   KC_F3,   KC_F12 ,
    KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, KC_TRNS, RESET  )
};

const uint16_t PROGMEM fn_actions[] = {

};

const macro_t *action_get_macro(keyrecord_t *record, uint8_t id, uint8_t opt) {
  // MACRODOWN only works in this function
  switch(id) {
    case 0:
      if (record->event.pressed) {
        register_code(KC_RSFT);
      } else {
        unregister_code(KC_RSFT);
      }
    break;
  }
  return MACRO_NONE;
};

I made some changes for my copy which I based on this gist:
https://github.com/kensanata/qmk_firmware/tree/master/keyboards/atreus/keymaps/workman
There's also a blog post but the interesting part is at the end, skip practically everything:
https://alexschroeder.ch/wiki/2018-08-22_Workman_on_the_Atreus

I just came back to this to find that my pgdwn is messed up, and found your blogpost saying exactly that. Note that the other changes I made to workman are to make dutch nicer to type.