Collection Types

LichenScript provides three primary collection types, known as tuples, arrays and maps.


In LichenScript, a tuple is a value that contains a fixed number of elements, each with its own type. Tuples are immutable.

Tuples are especially handy for returning multiple values from a method.

A tuple with two elements can be created as follows:

const tuple = ("one", 1);

This creates a tuple containing a string element and an i32 element.

Pattern matching on tuples

A tuple can also be taken apart using pattern matching:

match tuple {
case (name, num) => print("name: ", name, " num: ", num)

Here name’s inferred type is string and num's inferred type is i32.


const arr = [3, 2, 1, 4, 5];

Get the length of an array


Push elements to array

const a = [1,2,3,4,5,6,7,8];
let i = 0;
while i < 100 {
i += 1;

Slice an array

arr.slice(2, 3)

Resize array

Resize the array with a default value.

a.resize(10, 0);


Maps are collections of key-value associations.

let a = #{
"name": "Vincent Chan"

A map with type Map<string, string> will return.

Get a value from the map

let test = a.get("name");
match test {
case Some(name) => print("found: ", name)
case None => print("not found")