Lua dissector, loop vs table, what is supported?

edit

I've got a dissector with a loop that looks something like

 while i < payload_length do
    local tag_type=payload(i,1):uint()

    --Device Type
    if tag_type == 1 then
        tags_tree:add(hdhomerun_proto.fields.tag_device_type, payload(i+2,tag_length))   

    --Device ID
    elseif tag_type == 2 then
        tags_tree:add(hdhomerun_proto.fields.tag_device_id, payload(i+2,tag_length))

...

local hdhr_tag_types = {
[0x01] = ProtoField.new(...
[0x02] = ProtoField.new(...
[0x03] = ProtoField.new(...
}

and then have tags_tree:add(hdhr_tag_types[tag_type]) or something similar (where tags_tree is a subtree)

When I tried something like that it seemed like having a ProtoField in a table isn't supported.

For reference, the protocol I'm looking at is in https://github.com/Silicondust/libhdh...

What's supported? Is a loop with an if else statement for all 13 tags really the best way to make this work?