@verb #12:"set_brief" this none this rxdo #55
@program #12:"set_brief" this none this
"set_brief(value)"
"set_brief(value, anything)"
"If <anything> is given, add value to the current value; otherwise, just set the value."
if (!($perm_utils:controls(caller_perms(), this) || this == caller))
  return E_PERM
else
  if (length(args) == 1)
    this.brief = args[1]
  else
    this.brief = this.brief + args[1]
  endif
endif
.