use constant'ed constants are really subs that just return the same thing each time... there's no un-nasty way to interpolate them. TheDamian's perl best practices recommends using Readonly for constants for this reason.

Also  $input =~ /@{[ NAME ]}/ ... but if you do that, the maintenence programmer after you will hunt you down with a hatchet and do unspeakable things to you.

Enjoy ^_^