left hand keyboard toggle

I am designing code for a keyboard to be only used with left hand for a stroke patient in autohotkey. I need to use the space bar as a toggle button. So, when space bar is pushed it changes the output of the next key pushed. At the moment I can only find code for when it is pressed with another key. Please see below: ;QWERTY half-keyboard emulator SetKeyDelay, 50 mirror_1 = 0 mirror_2 = 9 mirror_3 = 8 mirror_4 = 7 mirror_5 = 6 mirror_q = p mirror_w = o mirror_e = i mirror_r = u mirror_t = y mirror_a = `; mirror_s = l mirror_d = k mirror_f = j mirror_g = h mirror_z = / mirror_x = . mirror_c = ,

Question by Amy on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.