Kiwi Language

Kiwi is a clean, expressive, and modern programming language with a .kiwi file extension. Designed to be readable and fun to write — not a clone of anything.

Install the Interpreter

pip install kiwi-lang

Then run any .kiwi file:

kiwi hello.kiwi
kiwi              # opens the REPL

What makes Kiwi different

Syntax

// Variables — let is immutable, mut is mutable
let name = "Kiwi"
mut score = 0

// String interpolation
show $"Hello from {name}!"

// Functions
fn factorial(n) {
    if n <= 1 { give 1 }
    give n * factorial(n - 1)
}

show factorial(10)   // 3628800

// Arrow shorthand
fn double(x) => x * 2
fn greet(n)  => $"Hey, {n}!"

// unless — cleaner than if not
unless score > 0 {
    show "No points yet."
}

// repeat
repeat 3 times {
    show "Kiwi!"
}

// each
let fruits = ["apple", "mango", "kiwi"]
each fruit in fruits {
    show $"  {fruit}"
}

// forever loop
mut i = 0
forever {
    i += 1
    if i >= 5 { break }
}

// Pipe operator |>
fn square(x) => x * x
fn big(x)    => x > 20

let nums = [1, 2, 3, 4, 5, 6, 7, 8]
let result = nums
    |> fn(l) => l.map(square)
    |> fn(l) => l.filter(big)

show result   // [25, 36, 49, 64]

// Null coalescing ?
mut username = null
show username ? "Guest"    // Guest

username = "melih"
show username ? "Guest"    // melih

// give — return alternative
fn clamp(val, lo, hi) {
    if val < lo { give lo }
    if val > hi { give hi }
    give val
}

// Match
let day = 3
match day {
    1 => show "Monday"
    2 => show "Tuesday"
    3 => show "Wednesday"
    _ => show "Other"
}

// List methods
nums.push(9)
nums.sort()
let squares = nums.map(fn(x) => x * x)
let evens   = nums.filter(fn(x) => x % 2 == 0)

show squares
show evens

// Math
show 2 ** 10        // 1024
show sqrt(144)      // 12
show abs(-7)        // 7
show round(3.14159, 2)  // 3.14

Built-in Functions

show · input · len · int · float · str · bool · type range · abs · max · min · round · floor · ceil · sqrt random · randint · sleep · exit

Language Basics

• Immutable by default — use let. Use mut to allow reassignment.
• No semicolons — newlines end statements.
• Curly braces {} for all blocks.
• First-class functions — pass them, store them, pipe them.
• give is return. Both work.
• show is print. Both work.

File Extension

.kiwi — this extension provides full syntax highlighting and file icons for VS Code.

Links

• GitHub
• PyPI

Created by Melih Yazar