Cannot get to initialize empty list in CameLIGO

Question

I'm trying to write a smart contract in CameLIGO that looks like this

parameters "Hello world"

storage [{ text = "Blob"; voters = ["tz1TKc3zQBMv7Rez77sX4JNdqMvG33LQrURk"]}]

with the following code

type voters = address list option

type item = {
   text : string;
   voters : voters
}

type items_storage = item list

let add_item (new_text, items_storage : string * items_storage) : items_storage =
let new_item : item = {
    text = new_text;
    voters = (* Cannot get to initialize to an empty list *)
}
in
new_item :: items_storage 

let main (p, s : string * items_storage) : operation list * items_storage =
(([] : operation list), add_item(p, s))

I don't know how to initialize an empty list.

Answer 1

If you want the voters to be optional then you need to initialize it with either the Some or None value constructors:

voters = Some ([] : address list)

or

voters = (None : address list option)