How to make ferret handle a variable number of arguments?

[Chi Ding <chi@xxxxxxxxx>]

Dear LAS users
        I'm building a LAS site for mooring data where the user can 
select a variable number of sensors ( up to 10 )
and draw the plots for each sensor in one picture.
        I implemented my own perl function in custom.pl to process the 
request from users. Thanks to the
help of Joe Mclean, now I'm able to extract the parameters in my perl 
code and pass them to my ferret script.
But I  have another problem , how to make ferret process a variable 
number of arguments? This is essential to
me since the user can select different number of sensors.
        I'm gonna try it in this way before I find a better solution. 
As the maximum number of sensors is 10, so I can fix the number of 
sensors passed to ferret to be a constant number 10.  I will pass the 
selected sensor names and missing values for the rest  to the  ferret 
script. For examples, if the user selected " salinity" and 
"temperature", I will pass them and 8 missing values. Then the ferret 
script can check the arguments and plot accordingly.
        I'm wondering whether  it is  possible to pass the actual 
selected number of sensors plus the sensor names to  ferret, then the 
ferret script can check the first arguement, i.e. the actual selected 
number, and accordingly plot the sensors. For example, if the user 
selected " salinity" and "temperature", I will pass "2", "salinity" and 
"temperature" instead of 10 sensor names.
        I'm looking forward to any suggestion.
        Thanks a lot, Ding