GitHub - lslvr/1wm: The smallest, actually usable window manager.

#include <X11/Xlib.h>
#include <stdlib.h>

#define stk(s)    XKeysymToKeycode(d, XStringToKeysym(s))
#define on(_, x)  if (e.type == _) { x; }
#define map(k, x) if (e.xkey.keycode == stk(k)) { x; }
#define grab(...) const char *l[] = { __VA_ARGS__, 0 }; \
                    for (int i = 0; l[i]; i++) XGrabKey(d, stk(l[i]), Mod4Mask, r, 1, 1, 1);

int main() {
  Display *d = XOpenDisplay(0); Window r = DefaultRootWindow(d); XEvent e;
  XSelectInput(d, r, SubstructureRedirectMask);
  grab("n", "q", "e");

  while (!XNextEvent (d, &e)) {
    on(ConfigureRequest, XMoveResizeWindow(d, e.xconfigure.window, 0, 0, e.xconfigure.width, e.xconfigure.height));
          on(MapRequest, XMapWindow(d, e.xmaprequest.window);
                         XSetInputFocus(d, e.xmaprequest.window, 2, 0));
            on(KeyPress, map("n", XCirculateSubwindowsUp(d, r); XSetInputFocus(d, e.xkey.window, 2, 0))
                         map("q", XKillClient(d, e.xkey.subwindow))
                         map("e", system("dmenu_run &")));
  }
}