confused about setting parameters/variables in dhcpd.conf and "set" keyword

[btb at bitrate.net]

On Mar 28, 2013, at 01.01, Glenn Satchell <glenn.satchell at uniq.com.au> wrote:

> The values get stored in the leases file in the lease for that client.
> 
> You'll need to stop dhcpd, edit dhcpd.leases to remove the line in every
> occurrence of the lease, then restart dhcpd.

ah, i see.  thanks.

regarding my other question about the "set" keyword - is this documented somewhere and i'm just missing it?  is it altogether a different mechanism than what is discussed in "SETTING PARAMETER VALUES USING EXPRESSIONS" section of man 5 dhcpd.conf?

thanks
-ben