diegocstn / lox

Another implementation of Lox programming language

Lox

Another implementation of Lox programming language from the awesome book craftinginterpreters by Bob Nystrom.

Lox is a dynamically typed programming language, its syntax is a member of the C family.

Data types

• boolean true; false;
• numbers 19 // integer 3.1415 // decimal
• strings "hello"
• nil

Expressions

Arithmetic

• a + b
• a - b
• a * b
• a / b
• - negateMe

Comparison and equality

• a < b
• a <= b
• a > b
• a >= b
• a == b
• 123 == 123 // true
• "123" == 123 // false

Logical operator

• and
• or
• !

Statements

• print "hakuna matata"
• { print "a block of statements"; print "hakuna matata btw"; }

Variables

• var name = "Clark";
• var lastname; // nil

Control Flow

if (somVariable == 5) {
  print "it's five!";
} else {
  print "it's not five.";
}

var a = 0;
while (a < 5) {
  print a;
  a = a + 1;
}

for (var i=0; i < 5; i = i +1) {
  print i;
}

Functions

fun makeBreakfastFor(name) {
  print "Breakfast for " + name; 
} // it returns nil

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

// functions are first-class in Lox
fun doSomeMath(a, b, op) {
  return op(a, b);
}
doSomeMath(sumPlease, 5, 6);

Lox also supports closures, local functions and block scope.

Classes

class Breakfast {
  init(name) {
    this.name = name;
  }
  cook() {
    print "Enjoy your breakfast " + this.name;
  }
}

class Brunch < Breakfast {
  init(name, drink) {
    super.init(name);
    this.drink = drink;
  }
}

var johnBr = Breakfast("John");
johnBr.cook(); // "Enjoy your breakfast John"