Quick overview

Comments

# Single-line comment

Variables

Example	Description
let x = Something(), let x: Int	Immutable value declaration
let x = 42, let x = 'Hello!'	Constant value declaration (case of primitive type assignment)
x = 42, x: Int, x: Int = 42	Variable declaration

Functions

(Function body can be omitted if it is not needed)

Function definition
fn greet	No return value, no parameters
fn greet (name: Str)	No return value
fn greet (name: Str, surname: Str)	No return value, multiple parameters
fn get-response -> Str	With return value, no parameters
fn response (input: Str) -> Str	With return value and parameter
fn makemap[T] (g: T, seq: List[T])	Generic function
Lambda (anonymous) function
fn (arg1: Int, arg2: Int)	With multiple parameters
cube = fn (x: int): x ** 3	With single named input argument x

Loops

# while is only loop directly baked in language
while condition
    do-something()

# all examples below use macros magic
do
    something()
while condition

x times
    do-something()

for x in 0..10
    Console.write-line(x)

for i = 0; i <= 10; i++
    Console.write-line(i)

'match' construction

Simple comparison:

digitAsWord = x match
    1: "one"
    2: "two"
    3: "three"
    # ...
    9: "nine"
    _: raise ArgumentOutOfRangeError

Pattern-matching:

alert = notification match
    Email(email, title, _):     f"Email from {email} with title: {title}"
    SMS(number, message):       f"SMS from {number}! Message: {message}"
    VoiceRecording(name, link): f"Voice Recording from {name}! Click to hear it: {link}"

Visual explanation for syntax nodes