A simple program that prints a greeting.

// Try some CoreLox code...
print "Hello, Lox!";

Basic output of an arithmetic expression.

print 3 * 4;

Demonstrates arithmetic operations in CoreLox.

// Simple arithmetic
print 10 + 2 * (3 - 1) % 2;  // 10

Declaring and reassigning variables.

var breakfast = "beignets";
print breakfast;
var beverage = "cafe au lait";
breakfast = "beignets with " + beverage;

print breakfast;

Demonstrates conditional branching.

var a = 3;
if (a == 3) {
    print a;
    a = 2;
}

if a == 3 then {
    print a;
    a = 1;
}
elif (a == 2) {
    print a;
    a = 5;
} else {
    print a;
    a = 4;
}

if a == 4 then print "yeah";
elif a == 5 then print "also yeah";

Basic for-loop iteration.

for(var a = 3; a > 0; a = a - 1) {
    print a;
}

A while-loop decrementing a variable.

var a = 3;
while(a > 0) {
    print a;
    a = a - 1;
}

Declaring and calling a function.

fun areWeHavingItYet() {
  print "Yes we are!";
}

print areWeHavingItYet;
areWeHavingItYet();

A function that returns a value.

fun sum(a, b) {
    return a + b;
}

print sum(3, 2); // 5

Demonstrates closures capturing variables.

var x = "global";
fun outer() {
  var x = "outer";
  fun inner() {
    print x;
  }
  inner();
}
outer();

Defines a class and creates an instance.

class Pair {}

var pair = Pair();
pair.first = 1;
pair.second = 2;
print pair.first + pair.second; // 3

Demonstrates class inheritance.

class Doughnut {
  cook() {
    print "Dunk in the fryer.";
  }
}

class Cruller < Doughnut {
  finish() {
    print "Glaze with icing.";
  }
}

var c = Cruller();
c.cook();
c.finish();

Calling methods on an object.

class Scone {
  topping(first, second) {
    print "scone with " + first + " and " + second;
  }
}

var scone = Scone();
scone.topping("berries", "cream");

Capturing a variable from an outer function.

fun outer() {
  var x = "outside";
  fun inner() {
    print x;
  }
  inner();
}
outer();

Demonstrating lexical scoping.

fun some() {
    var a = 3;
    print a;
}

some();

Using `break` in loops.

for(var a = 8; a > 0; a = a - 1) {
    if a == 5 then break;
    print a;
}

Demonstrates a switch-case structure.

var x = 3;

switch (x) {
    case 1: print "One";
    case 2: print "Two";
    case 3: print "Three";
    default: print "Default";
}

Closures capturing loop variables.

var globalOne;
var globalTwo;

fun main() {
  for (var a = 1; a <= 2; a = a + 1) {
    fun closure() {
      print a;
    }
    if (globalOne == nil) {
      globalOne = closure;
    } else {
      globalTwo = closure;
    }
  }
}

main();
globalOne();
globalTwo();

Example that causes a recursive stack overflow.

fun a() { b(); }
fun b() { c(); }
fun c() {
  c("too", "many");
}

a();

A recursive Fibonacci function with timing.

fun fib(n) {
  if (n < 2) return n;
  return fib(n - 2) + fib(n - 1);
}

var start = clock();
print fib(35);
print clock() - start;

One of the benchmarks used during development. Warning: slow! Might take a few seconds to run.

class Zoo {
  init() {
    this.aardvark = 1;
    this.baboon   = 1;
    this.cat      = 1;
    this.donkey   = 1;
    this.elephant = 1;
    this.fox      = 1;
  }
  ant()    { return this.aardvark; }
  banana() { return this.baboon; }
  tuna()   { return this.cat; }
  hay()    { return this.donkey; }
  grass()  { return this.elephant; }
  mouse()  { return this.fox; }
}

var zoo = Zoo();
var sum = 0;
var start = clock();
var time = clock() - start;
var batch = 0;

while(time < 10) {
    while (sum < 10000) {
        sum = sum + zoo.ant()
                    + zoo.banana()
                    + zoo.tuna()
                    + zoo.hay()
                    + zoo.grass()
                    + zoo.mouse();
    }
    sum = 0;
    batch = batch + 1;
    time = clock() - start;
}

print batch;