!distribute item ,, into randp,click1,click2
parm1=!trim $parm1
parm2=!trim $parm2
parm2=$[$parm2]

!if $parm1=$empty or $parm2=$empty
 error=empty_data
 !exit
!endif
!if $parm1 notwordof point line circle
 error=bad_object
 !exit
!endif
!if NaN isin $parm2
 error=bad_data
 !exit
!endif
!if $parm2<1 or $parm2>$($(parm1)cnt)
 error=out_range
 !exit
!endif

!if $step<$stepcnt
 !read proc/triminci
!endif
h=!char $parm2 of $(hide$parm1)
!if $h=+
 h=-
!else
 h=+
!endif
hide$parm1=!replace char number $parm2 by $h in $(hide$parm1)
steplist=!line 1 to $step of $steplist
steplist=!append line hide,$parm1,$parm2 to $steplist
!advance step

