How to count varargs[untyped] inside of template?

[r3d9u11]

Hi. I have a template with vararg[untyped] parameters, can I get count of 
parameters and realize branching like a: 
    
    
    template tmpl*(args: varargs[untyped]): untyped =
      when args.len > 0: # here is compilation will be excepted
        #...
      else:
        #...
    

Thanks.