new lua dissector error

edit

Check the Wireshark Wiki Examples dissector.lua and fpm.lua for field definition examples.
Also the Contrib Lua Plugins especially ones from @cmaynard like the Guacamole Dissector.

From the WSDG: 11.3.5.10. proto.fields:

11.3.5.10. proto.fields Mode: Retrieve or assign.

The ProtoField's Lua table of this dissector.

Here is a slight rewrite that creates the fields without error:

local globals = {}
globals.ENUM_DESCRIPTION={[0]="STOP", [1]="START"}

local demo_p = Proto("DEMO", "DEMO1")

local f = {
    a = ProtoField.new("zz", "demo.k.zz", ftypes.BYTES),
    b = ProtoField.uint8("demo.ZZ", "AA", base.dec, globals.ENUM_DESCRIPTION, 0x80)
}

demo_p.fields = f

View -> Internals -> Supported Protocols

Note to self: It can be confusing that (from WSDG)

11.3.7.1. ProtoField.new(name, abbr, type, [valuestring], [base], [mask], [description])

and

11.3.7.3. ProtoField.uint8(abbr, [name], [base], [valuestring], [mask], [description])

swap the abbr and name Argument positions.