Functions

A function is a block of code that can be called any time multiple times. These functions can also take parameters to change their outcome and can return values when called too.

Define a function using the fn keyword followed by its name, parenthesese, and a block. (Optional parameters can go inside the parenthesese).

fn my_function() {
    print("foo")
    print("bar")
}

Call a function to run it by writing its name, followed by parenthese and any arguments it takes.

my_function()

Example

Here’s a simple add() function that takes 2 numbers and prints their added output:

fn add(a, b) {
    print(a + b)
}

add(1, 3)
add(6, 7)
add(12, 51)

Returning Values

Use the return keyword (or out) to stop a function and optionally return a value.

fn times_five(num) {
    return num * 5
}

print(times_five(6))  # prints 30

Lambda Functions

Functions are actually first class objects that can be manipulated and passed around. This allows you to write functions without names and just as an object.

Use fn followed by parenthese + arguments (no function name) and a block.

let x = fn() {
    print("yes")
}

# Or make it inline

let x = fn() => print("yes")

You can call x() to run the function or pass it to a separate function. This can be useful for creating callbacks and assigning functions to certain things at runtime.

Example

If there was a button object like the one below, we can make a function that prints clicked! as a callback. (And also make it a one liner arrow function)

button.on_click(
    fn() => print("clicked!")
)