#!/usr/bin/env rc

current=`{basename $%}
currentx=`{9 grep -n '^'$current'([ 	]|$)' index | sed 's/:.*//'}
pagex=`{echo $currentx - 1 | hoc}
page=`{sed -n $pagex^p index | awk '{print $1}'}

if(~ $#page 0) {
	echo no such page
	exit 0
}

Slide $page