robjsliwa/rlox

rlox language

Rlox

Rlox is simple language designed purely to learn how build interpreters.

Rlox is a clone of lox langauge from https://craftinginterpreters.com/ book. Lox was written in Java and C and Rlox is a clone written in Rust just for fun.

NOTE - This is work in progress. Branch tree-walk contains tree walking interpreter.

Running REPL

Currently REPL it is very basic but you can execute all of the commands from it. To run REPL just cargo run

Running Rlox code from file

cargo run -- -i path/filename.rl

Run tests

cargo t

Some example code

Compute Fibonacci

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

for (var i = 0; i < 20; i = i + 1) {
  print fib(i);
}

Closures

var a = "global";
{
  fun showA() {
    print a;
  }

  showA();
  var a = "block";
  showA();
}

fun test() {
  print a;
  a=a+"!";
  return a;
}

print test();

Classes and Inheritance

class Doughnut {
  cook() {
    return "Fry until golden brown.";
  }

  cookAnother() {
    return "Fry until golden.";
  }
}

class BostonCream < Doughnut {
  cookAnother() {
    var orig = super.cookAnother();
    return orig + " Then pipe full of custard and coat with chocolate.";
  }
}

var first = BostonCream().cook();
print first;

var second = BostonCream().cookAnother();
print second;