Does array in REGO support the operation like append and extend

[lemonshir]

I'd like to know if operation like append and extend is supported by array. If yes, could you point me to any doc link? If not, what's the best practice to achieve this in the current REGO? Can it be added in REGO natively in the future?

[anderseknert]

Hi @lemonshir!

Rego variables and values are immutable, so there's no way to modify them directly. Like most languages with immutable values and vars, you can however use functions that return new values or collections to achieve the same outcome. For your example of appending to an array, you can use the array.concat built-in:

a := [1, 2, 3]
b := [4, 5, 6]
c := array.concat(a, b)

# c == [1, 2, 3, 4, 5, 6]