o<change> sub
;(debug, in change tool_in_spindle=#<tool_in_spindle> current_pocket=#<current_pocket>)
;(debug, selected_tool=#<selected_tool> selected_pocket=#<selected_pocket>)

;otherwise after the M6 this information is gone!
#<tool> = #<selected_tool>
#<pocket> = #<selected_pocket>

o100  if [#<tool_in_spindle>=<#selected_tool>]
o100      o<change> endsub [1]
o100 endif

; we must execute this only in the milltask interpreter
; or preview will break, so test for '#<_task>' which is 1 for 
; the milltask interpreter and 0 in the UI's
O200 if [#<_task> EQ 0]
        (debug, Task ist Null)
O200     return [999]
O200 endif

;first go up
G53 G0 Z[#<_ini[CHANGE_POSITION]Z>]
; then move to change position
G53 G0 X[#<_ini[CHANGE_POSITION]X>] Y[#<_ini[CHANGE_POSITION]Y>]

; cancel tool offset
G49

; using the code being remapped here means 'use builtin behaviour'
M6

O300 if [#<_hal[gmoccapy.toolmeasurement]> EQ 0]
O300 return [3] ; indicate no tool measurement 
O300 endif

G53 G0 X[#<_ini[TOOLSENSOR]X>] Y[#<_ini[TOOLSENSOR]Y>]
G53 G0 Z[#<_ini[TOOLSENSOR]Z>]

O400 if [#<_hal[gmoccapy.searchvel]> LE 0]
O400 return [-1] ; indicate searchvel <= 0 
O400 endif

O500 if [#<_hal[gmoccapy.probevel]> LE 0]
O500 return [-2] ; indicate probevel <= 0 
O500 endif

F #<_hal[gmoccapy.searchvel]>
G91
G38.2 Z #<_ini[TOOLSENSOR]MAXPROBE>
;G0 Z2
G0 Z0.5
; This is commented out only for sim.
F #<_hal[gmoccapy.probevel]>
;G38.2 Z-4
G38.2 Z-0.75

O600 if [#5070 EQ 0]
G90
O600 return [-3] ; indicate probe contact failure to epilog
O600 endif

G90
G53 G0 Z[#<_ini[CHANGE_POSITION]Z>]

#<touch_result> = #5063
#<probeheight> = #<_hal[gmoccapy.probeheight]> 
#<blockheight> = #<_hal[gmoccapy.blockheight]>

;(DEBUG, #<touch_result>  #<probeheight>  #<blockheight>)

G10 L1 P#<tool> Z[#<touch_result> - #<_hal[gmoccapy.probeheight]> + #<_hal[gmoccapy.blockheight]>]
G43

G0 G54 Y0.0 X0.0


;G10 L2 P0 Z[#<touch_result> - #<_hal[gmoccapy.probeheight]> + #<_hal[gmoccapy.blockheight]>]
;G10 L2 P1 Z[#<touch_result> - #<_hal[gmoccapy.probeheight]>]
;G54 G0 Y0.0 X0.0


; signal success be returning a value > 0:
o<change> endsub [1]