using env in proxy.conf as the realm name

[Andrei Katsuk]

Hello,
I tried to define realms in proxy.conf in following way:

realm $ENV{DOMAIN_NAME} {
}

realm $ENV{NETBIOS_NAME} {
}

but FreeRADIUS shows error during the start :
etc/raddb/proxy.conf[7]: Parse error after "DOMAIN_NAME": unexpected token "}"

Does FreeRADIUS support environmental variables ?

Thanks,
Andrei