There are two special shot ``numbers''. ``LAST'' accesses the current value of the system wide logical variable TFTR_SHOT, which is updated when data for a new shot is ready. When TFTR is shut down it is the last shot of the previous run. ``NEXT'' causes CUPLOT\ to wait for the next shot to occur; when TFTR_SHOT is updated CUPLOT wakes up and uses the new value:
DE NB-BP-SL ;
A shot number of ``.-n'' uses the previous SH value minus n when n 20; ``.+n'' uses the previous SH shot plus n:
DE M-ETOT ;
SH LAST !most recent shot
SH .-1 !one before that
SH .+2 !two after that
The default value for the SH shot number is one more than the previous value, thus ``SH .+1'' is equivalent to ``SH ,''.