;Super-free. Performs a recursive free on anything passed in.
;1. If it is a pointer or array of pointers, str_free is called on *s.
;   The pointer is then freed
;2. If it is a structure or array of structures, str_free is called on
;   each field of each element of the structure
;3. If it is an object, call obj_destroy. The object needs to have a
;   cleanup method to free its own pointers.
pro str_free,s
  case size(s,/type) of
    8: begin ;Structure
      for i=0LL,n_elements(s)-1 do begin
        for j=0,n_tags(s[i])-1 do begin
          str_free,s[i].(j)
        end
      end
    end
    10: begin ;Pointer
      for i=0LL,n_elements(s)-1 do begin
        if ptr_valid(s[i]) then begin
          str_free,*(s[i])
        end
      end
      ptr_free,s
    end
    11: begin ;Object reference
      obj_destroy,s
    end
    else: begin
      ;Don't have to do anything
      return
    end
  end
end