anchor.diff:    genByte = s: n: toString (hexByteToInt (
       substring n 2 (mkMAC s)
     ));
  -
  -  netPrefix = "10.${genByte cfg.name 0}.";
   
     instanceOpts = { name, config, lib, ... }: {
       imports = [
  
positive.code:         gid="$(id -g)"
          pwd="$(pwd)"
          starttime="$(now)"
  
          function log() {
            printf "%05d %s\n" $(($(now) - $starttime)) "$1"
  
negative.code:       <name>net-@testid@</name>
        <bridge name="virbr-@testid@" stp="off"/>
        <domain name="${cfg.domain}" localOnly="yes"/>
        <ip address="10.@subnet@.0.1" netmask="255.255.0.0">
          <dhcp>
            <range start="10.@subnet@.0.2" end="10.@subnet@.255.254" />
            ${concatStrings (mapAttrsToList (name: i: ''
              <host mac="${i.mac}" name="${name}" ip="${i.ip}"/>
            '') cfg.instances)}
  