#ascii chars
:local ascii1 ("0123456789")
:local ascii2 ("abcdefghijklmnopqrstuvwxyz")
:local ascii3 ("-")
:local ascii ($ascii1 . $ascii2 . $ascii3)

#ascii values
:local val1 "30,31,32,33,34,35,36,37,38,39,"
:local val2 "61,62,63,64,65,66,67,68,69,6a,6b,6c,6d,6e,6f,70,71,72,73,74,75,76,77,78,79,7a,"
:local val3 "2d"
:local val [:toarray ($val1 . $val2 . $val3)]

#hex chars
:local hex "0123456789ABCDEF"

:local hn  [/system identity get name]
:local hnld [:len $hn]

:global hout ""
:global tmp ""
:local cnt 0

:for pc from 0 to ($hnld-1) do={
    :local chr [:pick $hn $pc]

    :if ($chr != "." ) do={
        :local pa [:find $ascii $chr]
        :local hv [:pick $val $pa]
        :set tmp ( $tmp . $hv )
        :set cnt ($cnt + 1)
    } else {
        :local hnlh [:pick $hex $cnt]
        :set hout ( $hout . "0" . $hnlh . $tmp)
        :set cnt 0
        :set tmp ""
    }
}

:local hnlh [:pick $hex $cnt]
:set hout ( $hout . "0" . $hnlh . $tmp)

:local out ( "0x01" . $hout . "00")
:log info "$hn -> $out"
/ipv6 dhcp-client option set 0 value=$out code=39 name=option39

/ipv6 dhcp-client option
add code=39 name=option-39 value="0x0108'test-mkt'0x03'lan'0x00"

#hex chars
:local hex "0123456789ABCDEF"
...
:local hnlh [:pick $hex $cnt]
hnlh = length in hex

:global fqdn2encdns do={
    :local charsString ""
    :for x from=0 to=15 step=1 do={ :for y from=0 to=15 step=1 do={
        :local tmpHex "$[:pick "0123456789ABCDEF" $x ($x+1)]$[:pick "0123456789ABCDEF" $y ($y+1)]"
        :set $charsString "$charsString$[[:parse "(\"\\$tmpHex\")"]]"
    } }

    :local chr2lcase do={
        :local chrValue [:find $2 $1 -1]
        :if (($chrValue > 64) and ($chrValue < 91)) do={
            :return [:pick $2 ($chrValue + 32) ($chrValue + 33)]
        } else={
            :return $1
        }
    }

    :local numbyte2hex do={
        :local input [:tonum $1]
        :local hexchars "0123456789ABCDEF"
        :local convert [:pick $hexchars (($input >> 4) & 0xF)]
        :set convert ($convert.[:pick $hexchars ($input & 0xF)])
        :return $convert
    }

    :local input "$1"
    :local fqdn ""
    :local encdns "0x01''"
    :if ($input~"^(([a-zA-Z0-9][a-zA-Z0-9-]{0,61}){0,1}[a-zA-Z]\\.){1,9}[a-zA-Z][a-zA-Z0-9-]{0,28}[a-zA-Z]\$") do={
         :for y from=0 to=([:len $input]-1) step=1 do={
             :set fqdn "$fqdn$[$chr2lcase [:pick $input $y] $charsString]"
         }
         :local workstr $fqdn
         :local dotidx  0
         :while ([:typeof [:find $workstr "." -1]] != "nil") do={
             :set dotidx [:find $workstr "." -1]
             :set encdns "$"encdns"0x$[$numbyte2hex $dotidx]'$[:pick $workstr 0 $dotidx]'"
             :set workstr [:pick $workstr ($dotidx + 1) [:len $workstr]]
         }
         :return "$"encdns"0x$[$numbyte2hex [:len $workstr]]'$workstr'0x00"
    } else={
        :return ""
    }
}

:put [$fqdn2encdns www.thisismydomainname.net]     
0x01''0x03'www'0x12'thisismydomainname'0x03'net'0x00

/ipv6 dhcp-client option
set [find where code=39] value=[$fqdn2encdns www.thisismydomainname.net]