what does prepending a "+" to an argument to vip do?

[polifemo]

reading through the file @bin/vip, I found this line:

((pre? "+" S)

inside this function

(bye
   (if
      (vip~vi
         (make
            (while (opt)
               (let S @
                  (cond
->>                  ((pre? "+" S)
                        (link
                           (cons
                              (cond
                                 ((= "+" S) T)
                                 ((format S) @)
                                 (T (cdr (chop S))) )
                              (opt) ) ) )
                     ((pre? "-" S) (load S))
                     (T (link S)) ) ) ) ) )
      0
      1 ) )

I think it means "do something special when the argument starts with "+".
But I don't know what that is.

I've tried running `vip +hello`, and it opens a temporary file in the
picolisp tmp folder (~/.pil/tmp) but if that's all it did, why bother
adding the name stuff?

thanks for your help.