string symbols

[Andrea Sardinha Taschetto <andreast@xxxxxx>]

Dear all ferret user,
 
I need to read 5 files and make climatological plots. I'd like to do it using 
string symbols, so I wrote the following script:
yes? define symbol var1=sst
yes? define symbol var2=slp
yes? define symbol var3=prec
...
then I want to read this files,
yes? use data_($var1).cdf
yes? use data_($var2).cdf
yes? use data_($var3).cdf
...
My question is: 
Is there any way to use recursive definitions and string symbols together? 
Does anyone know how could I read and contour my data using something like:
yes? REPEAT/l=1:5 (use data_($var`l`).cdf, contour ($var`l`)[l=1:12@ave])
Thanks,
Andrea.