The help file is incomplete, there is a support for /write (and maybe others commands with the same situation) where the parameter of a switch can be space seperated as it does not interfere with the general parsing scheme.
The same way, for example, all of the token number parameters can be space seperated
$gettok(a b c, 2 - 3,32)
$gettok(a b c,2- 3,32)
$gettok(a b c,2 -3,32)
if ($1 isnum 50 - 96) echo -a ok etc