Re: checked attribute for a checkbox input

>
>I use a snippet like
>(NET.HTML.GENERATOR:HTML
>          ((:input :type "Checkbox"
>                   :name id
>                   :value aValue
>                   :if* (my-lisp-function aValue) :checked "CHECKED"
>                   )
>           (:princ aValue)
>           :newline
>           )
>          )

Is this (and anything else like it) documented somewhere?

A quick perusal of the Allegroserve tutorial and manual don't
reveal anything obviously relevant to this.