How to move a variable value with G-code

import linuxcnc
s = linuxcnc.stat()
c = linuxcnc.command()

def ok_for_mdi():
s.poll()
return not s.estop and s.enabled and (s.homed.count(1) == s.joints) and (s.interp_state == linuxcnc.INTERP_IDLE)


x = 1.23
y = 2.34
if ok_for_mdi():
   c.mode(linuxcnc.MODE_MDI)
   c.wait_complete() # wait until mode switch executed
   c.mdi("G0 X%s Y%s " % (x, y))

import hal
self.hal = hal.component("vision")
self.hal.newpin("enable", hal.HAL_BIT, hal.HAL_IN)
self.hal.newpin("done", hal.HAL_BIT, hal.HAL_OUT)
self.hal.newpin("input_value", hal.HAL_FLOAT, hal.HAL_IN)
self.hal.newpin("output_value", hal.HAL_FLOAT, hal.HAL_OUT)
self.hal.ready()

net camera-enable <= motion.digital-out-00 => vision.enable
net camera-done <= vision.done => motion.digital-in-00
net camera-val-in <= motion.analog-out-00 => vision.input-value
net camera-val-out <= vision.output-value => motion.analog-in-00

m66 p0 l3 q2    ; wait for vision.done to go HIGH with 2 seconds timeout
o100 if [#5399 le 0]    ; timeout occured
    #1000 = 0
    (DEBUG, vision: timeout)
o100 else
    m66 e0 l0    ; read vision.output-value which is stored in #5399
    #1000 = [#5399]
o100 endif