clox

NOTE: We use git submodules, so make sure to clone this repo with git clone --recursive

This is my C99 implementation of Robert Nystrom's Crafting Interpreters single-pass compiler and bytecode virtual machine for the Lox programming language.

Sample Lox script

var t0 = clock();

{
	print "Hello, World!";    // => "Hello, World!"
	print ("a" + "a") + "aa"; // => "aaaa"
	print 123 == "123";       // => false
}

fun empower(operation, base) {
	fun power(x, n) {
		var y = base;
		while (n > 0) {
			y = operation(y, x);
			n = n - 1;
		}
		return y;
	}
	return power;
}
fun add(a, b) { return a + b; }
fun printfn(x) { print x; }

{
	print add(4, 3);             // => 7

	var times = empower(add, 0);
	print times(4, 3);           // => 12

	var pow = empower(times, 1);
	print pow(4, 3);             // => 64
}

{
	print add("Hello, ", "World!"); // => "Hello, World!"
	var repeat = empower(add, "");
	print repeat("a", 4);           // => "aaaa"
}

class A {
	init() {
		error("K.O."); // should never run
	}
}
class B < A {
	init() {
		print "OK";
	}
	foo(x) {
		print this;
	}
}

{
	var obj = B(); // => "OK"
	obj.foo(nil);  // => B instance
	setField(obj, "foo", printfn);
	obj.foo("ok"); // => "ok"
}

print clock() - t0;

Notes

Please note that the code here - just like in most Lox implementations - is somewhat lacking in internal algorithmic documentation and relies on the book for that purpose.

In this version there are no global variables and function-like preprocessor macros are limited to the file where they are defined (macros in headers were substituted by inline functions).

Licensing

Since this is what Bob chose with respect to the book's code, the Lox implementation uses the MIT License.

Meanwhile, the generic data structures used throughout the codebase were implemented in a separate submodule "Unsafe Generic Library" (UGLy), which has its own license.